Retinopatia deficiente de taurina em uma gata / Taurine deficiency retinopathy in a cat

Background: Taurine is an essential amino acid for cats and its deficiency causes an ocular disorder called taurine deficiency retinopathy. The retinal lesion is definitive and can be classified into five progression stages. In an advanced stage, it leads to blindness that in most cases is irreversible. This disease is considered rare as taurine is currently supplemented in commercial cat food. The objective of this report is to describe the ophthalmic changes in a cat with advanced taurine deficiency retinopathy, a rare but current disease that is important for differential diagnosis of blindness in cats. Case: We report the case of an adult mixed-breed cat (weighing 3.4 kg), that was attended by the Ophthalmology Service of the College of Veterinary Medicine and Animal Science (UNESP - Botucatu), which was treated due to complaints of poor visual acuity for about 1 year. The animal, which was previously a stray animal, had been adopted for 2 years and provided premium cat food ad libitum. Ophthalmic examination showed bilateral mydriasis, with negative menace, direct pupillary, and consensual light reflexes. No change was observed in the ocular appendages, cornea, anterior chamber, lens, and vitreous humor. The eyes were normotensive and fluorescein test negative. Direct and indirect fundoscopy revealed an area of ellipsoidal hyperreflexia with darkened margins laterally to the optic nerve disk in the tapetal region and intense retinal vascular attenuation in both eyes, with a diagnosis of taurine deficiency retinopathy. Complete blood count and biochemical analysis parameters were within the normal range, including the leukocyte count. The guardian was instructed to continue feeding the cat balanced cat food and received information on the proper care and management of a blind animal. Discussion: Although taurine deficient retinopathy is currently underdiagnosed due to the supplementation of this amino acid in commercial cat food, animals that are not properly fed, such as those receiving dog food or homemade food, may be deficient in this amino acid. Taurine deficiency and in this case, the consequent taurine deficiency retinopathy, was diagnosed by visualizing the lesion characteristic of this amino acid deficit since no other retinal change presents this aspect in cats. Therefore, this lesion is considered pathognomonic of this deficiency. Hyperreflective retinal lesions with darkened margins indicate the slow chronic progression in the already stabilized lesions. The animal in this report presented pigmented lesion margins, indicating the chronicity of these retinal changes. Moreover, lesion signs are visible on fundoscopy only after a period of 2-11 months of nutritional amino acid deficiency, and complete retinal atrophy usually occurs after at least nine months of taurine deficiency. Thus, complete blindness associated with advanced retinal changes reinforced the suspicion that the animal had taurine deficiency for a prolonged period of time prior to its adoption. Its guardian was instructed to provide balanced commercial cat food, because although retinal lesions are irreversible, cardiac changes resulting from taurine deficiency are reversed with dietary supplementation. In addition, taurine deficiency affects other organs and systems, such as the central nervous, immune, and reproductive systems. In conclusion, although taurine deficiency retinopathy is currently rare, this condition should be considered one of the possible differential diagnoses for blindness in feline patients.

Assessing ultrasonographic optic nerve sheath diameter in animal model with anesthesia regimens

Purpose: To determine the normal optical nerve sheath (ONS) diameter ultrasonography (ONSUS) and evaluate the possible effects of drugs on ONS diameter during anesthetic induction in healthy pigs. Methods: Healthy piglets were divided into three groups: a control group, that received xylazine and ketamine (X/K); other that received xylazine, ketamine and propofol (X/K/P); and a third group that received xylazine, ketamine, and thiopental (X/K/T). The sheath diameter was assessed by ultrasonography calculating the average of three measurements of each eye from the left and right sides. Results: 118 animals were anesthetized (49 X/K 33 X/K/P and 39 X/K/T). Mean ONS sizes on both sides in each group were 0.394 ± 0.048 (X/K), 0.407 ± 0.029 (X/K/P) and 0.378 ± 0.042 cm (X/K/T) (medians of 0.400, 0.405 and 0.389, respectively). The ONS diameter varied from 0.287-0.512 cm (mean of 0.302 ± 0.039 cm). For group X/K, the mean diameter was 0.394 ± 0.048 cm. Significant differences in ONS sizes between the groups P and T (X/K/P > X/K/T, p = 0.003) were found. No statistically significant differences were detected when other groups were compared (X/K = X/K/P, p = 0.302; X/K = X/K/T, p = 0.294). Conclusions: Sedation with thiopental lead to significative ONS diameter reduction in comparison with propofol. ONSUS may be useful to evaluate responses to thiopental administration.

Rare primary choroidal melanoma in a dog, with optic nerve infiltration / Raro melanoma primário de coroide em cão, com infiltração no nervo óptico

Intraocular melanocytic neoplasms are common in dogs. However, the choroidal location of these neoplasms and their infiltration into the optic nerve are unusual. This paper reports a case of primary choroidal melanoma in a 12-year-old male Dachshund. On the first examination, the animal presented left eye blepharospasm, protrusion of the nictitating membrane, conjunctival hyperemia, moderate congestion, hyphema, and intraocular hypertension. Opacity hindered the performance of fundoscopy in the affected eye. The ocular ultrasound examination revealed a cupuliform mass in the choroid. Due to suspected intraocular neoplasia, an exenteration was performed. Histopathological examination revealed primary choroidal melanoma with scleral and optic nerve invasion.(AU)

Neoplasias melanocíticas intraoculares são comuns em cães, contudo, a localização destas neoplasias na coroide e a infiltração delas no nervo óptico são pouco frequentes. O presente trabalho relata um caso de melanoma de coroide primário em um cão da raça Dachshund, com 12 anos de idade. O animal ao primeiro exame apresentou blefaropasmo no olho esquerdo, protrusão da terceira pálpebra, hiperemia conjuntival, congestão moderada, hifema e pressão intraocular elevada. Opacidade de meios transparentes impediu a realização de fundoscopia no olho acometido. O exame ultrassonográfico ocular revelou massa cupuliforme na coroide. Em razão da suspeita de neoplasia intraocular foi realizada exenteração. No exame histopatológico foi diagnosticado melanoma primário em coroide com invasão escleral e do nervo óptico.(AU)

Criptococoma retrobulbar mimetizando tumor em labrador retriever / Retrobulbar cryptococcoma mimicking tumor in a Labrador Retriever

Background: Cryptococcosis is a systemic mycotic disease caused by encapsulated yeasts C. neoformans and C. gattii. Cryptococcus neoformans is predominantly found in soils and feces of pigeons and psittacids. Infection occurs mainly through the respiratory tract, through the inspiration of fungal propagules (basidiospores and/or desiccated yeast cells). The main lesions observed are in the nasal cavity and lungs, but in dogs, the central nervous system and eyes are widely affected. Despite some previously mentioned reports, the retrobulbar form has not been described in the literature. Therefore, the purpose of this report is to describe a case of retrobulbar cryptococcoma mimetizing a tumor in a young bitch. Case: A 2-year-old female Labrador Retriever, was admitted to one Veterinary Hospital with exophthalmia on the left eye for 15 days and other signs included negative retropulsion, mydriasis, and abscence of menace and pupillary reflexes. Ocular ultrasound imaging revealed a hyperecotic and heterogeneous retrobulbar mass in the mid-dorsal region compressing the optic nerve. Computed tomography of the skull showed the presence of proliferation of neoplastic tissue in a locally invasive retrobulbar region promoting moderate rostrolateral displacement of the left ocular bulb, discrete osthelysis in maxillary bone, palatine, medial wall of the orbital bone and frontal bone, with destruction of cribiform plate adjacent to the dorsal region of the orbital wall and presence of mild contrast uptake in the region of the left olfactory bulb lobe, characterizing a picture compatible with neoplasia with malignancy and locally invasive characteristics. Exenteration and excision of part of the frontal bone were performed and histopathological examination revealed granulation with the presence of fibroblasts and numerous typical blastoconidia of Cryptococcus neoformans. The patient was treated with Itraconazole [10 mg/kg, v.o, SID, for 90 days] and one year after diagnosis, X-ray was performed to control the lesion and radiographic aspects were within normal limits. Discussion: Cryptococcus sp. is an environmental fungus that has the potential to be pathogenic to humans and animals. Fungus present as a basidiospores in pigeon droppings. The patient described had a history of contact with free-living pigeons, making it a risk factor for the occurrence of cryptococcosis, being the possible cause of the infection. In dogs, the disease is mainly described in immunosuppressed animals, which was not the case of the patient, who presented clinical and laboratory results within the normal range and without a previous history of use of immunosuppressants. The alterations described in the computed tomography, such as destruction of the cribriform plate adjacent to the dorsal region of the left orbital wall and the presence of slight contrast uptake in the left olfactory bulb lobe region, are compatible with the main entry point for propagules of Cryptococcus sp. In the present case, no periocular and ocular alterations were observed as described in the literature, and the lesion was restricted to the retrobulbar space. Ultrasonography and computed tomography revealed a neoformation mimicking a malignant neoplasm and the diagnosis of cryptococcoma was revealed by histopathology. Based on the present case, cytology through aspiration of retrobulbal neoformations is imperative as a diagnostic method, especially in endemic areas for fungal diseases that can mimic ocular neoplasms.

Accidental closantel poisoning in sheep in the State of Rio Grande do Sul - Brazil

Background: Verminosis is one of the major health problems in sheep flocks, and is one of the main causes of death insheep worldwide. Closantel is an antiparasitic drug commonly used in sheep; however, its safety margin is narrow, andthis drug may induce intoxication in animals submitted to high doses. Lesions occur mainly in the eyes, and are characterized by edema and compression of the optic nerve, retinopathy, and severe degeneration of ganglia cells. Clinical signsare pupil dilation, which often lead to permanent blindness. This work aims to report an outbreak of sheep mortality dueto closantel intoxication, associated with inadequate anthelmintic administration practices.Case: An on-site visit was conducted to a sheep farm, located in the municipality of Osório, Rio Grande do Sul (RS)- Brazil, in which high mortality was reported. The flock consisted of approximately 300 Texel sheep, managed in anextensive grazing system. Lambs and adult animals were affected. According to the information provided by the farmowner, many animals presented clinical signs of haemonchosis, and a closantel dose of 20 mg / lamb was administeredin all sheep, regardless of body weight. Lambs weighted on average 13 kg. After closantel administration, several sheeppresented neurologic signs and died. At the clinical examination, sheep presented pallor of ocular mucous membranes,as well as submandibular edema. Also, 20 lambs showed signs of blindness, disorientation and bumping into objects, aswell as hypothermia and lack of response to the menace reflex. Three 30 to 45-day-old male lambs that died spontaneously were submitted for necropsy. Grossly, only mild ascites was noted. Histopathological examination of the retinashowed degeneration and fragmentation of photoreceptor layer as well as depletion of the inner nuclear layer, associatedwith pyknosis and karyorrhexis. There was also a reduction in the number of ganglia cells in the ganglion cell layer andatrophy...

Accidental closantel poisoning in sheep in the State of Rio Grande do Sul - Brazil

Background: Verminosis is one of the major health problems in sheep flocks, and is one of the main causes of death insheep worldwide. Closantel is an antiparasitic drug commonly used in sheep; however, its safety margin is narrow, andthis drug may induce intoxication in animals submitted to high doses. Lesions occur mainly in the eyes, and are characterized by edema and compression of the optic nerve, retinopathy, and severe degeneration of ganglia cells. Clinical signsare pupil dilation, which often lead to permanent blindness. This work aims to report an outbreak of sheep mortality dueto closantel intoxication, associated with inadequate anthelmintic administration practices.Case: An on-site visit was conducted to a sheep farm, located in the municipality of Osório, Rio Grande do Sul (RS)- Brazil, in which high mortality was reported. The flock consisted of approximately 300 Texel sheep, managed in anextensive grazing system. Lambs and adult animals were affected. According to the information provided by the farmowner, many animals presented clinical signs of haemonchosis, and a closantel dose of 20 mg / lamb was administeredin all sheep, regardless of body weight. Lambs weighted on average 13 kg. After closantel administration, several sheeppresented neurologic signs and died. At the clinical examination, sheep presented pallor of ocular mucous membranes,as well as submandibular edema. Also, 20 lambs showed signs of blindness, disorientation and bumping into objects, aswell as hypothermia and lack of response to the menace reflex. Three 30 to 45-day-old male lambs that died spontaneously were submitted for necropsy. Grossly, only mild ascites was noted. Histopathological examination of the retinashowed degeneration and fragmentation of photoreceptor layer as well as depletion of the inner nuclear layer, associatedwith pyknosis and karyorrhexis. There was also a reduction in the number of ganglia cells in the ganglion cell layer andatrophy...(AU)

B-Mode and Doppler ocular ultrasound evaluation in healthy and positive dogs for visceral canine leishmaniasis

Background: The use of ultrasound examination in the evaluation of ophthalmopathies has been gaining more and more space within the ophthalmologic clinical routine. The hemodynamic study of ocular vascularization may anticipate future changes, aiding in the adequate establishment of therapeutic conduits. The objective of this study was to evaluate the structures of the ocular bulb and to perform the hemodynamic evaluation of the flow of the external ophthalmic artery of dogs with canine visceral leishmaniasis (CVL) correlating with healthy animals. Materials, Methods & Results: For this purpose, 100 animals were used, of these 70 positive for CVL and 30 healthy animals, submitted to B-mode and Doppler ultrasound examination. Two-dimensional evaluation included identification of ocular changes and biometry of the following segments: axial length (M1), anterior chamber depth (M2), lens thickness (M3), lens length (M4), glass chamber depth (M5), optical disc length (M6) and optic nerve length (M7). The Doppler velocimetric evaluation included the identification and hemodynamic evaluation of the external ophthalmic artery, being measured: systolic peak velocity (SPV), final diastolic velocity (FDV), resistivity index (RI) and pulsatility index (PI). Ophthalmopathies were frequent in animals with leishmaniasis in both right (91.42%) and left (29.14%) eyes, with identification of capsular cataract, lens dislocation, retinal detachment and lens rupture. No significant statistical difference (P > 0.05) was observed when comparing the biometric values between the right and left eyes of the animals with CVL, as well as for the measurements between healthy and CVL animals. Hemodynamic indexes of the flow of the external ophthalmic artery presented narrow limits for the right and left eyes of the positive animals, not statistically...

Metacercariae of Austrodiplostomum spp. (Digenea: Diplostomidae) infecting the eyes and brains of fish in Brazilian Amazon / Metacercaria de Austrodiplostomum spp. (Digenea: Diplostomidae) infectando olhos e cérebros de peixes na Amazônia Brasileira

The aim of this paper was to report the occurrence of Austrodiplostomum spp. in the eyes and brain of Acaronia nassa, Caquetaia spectabilis, Satanoperca acuticeps, Curimatella sp. and Crenicichla marmorata in a lake of the Amazon River system in the state of Pará (Brazil). Of 49 fish examined, 10.2% were parasitized by Austrodiplostomum spp. metacercariae, and A. nassa was the host with higher number of metacercariae. In five examined fish species, a total of 51 metacercariae were collected, with 45 found in the eyes and 6 in the cranial vault. In the eyes, the metacercariae were free and active in the vitreous humor, but no opacification was observed. In the brain, the metacercariae were also free and active, and located mainly below the encephalon, on the cranial floor, at the height of the ophthalmic lobes and near the optic nerve. In laboratory observations, however, the infected fish did not exhibit any behavioral disorders, and this may be related to the low level of parasitism. This was the first report of this digenean for C. spectabilis, S. acuticeps, Curimatella sp., C. marmorata and A. nassa.(AU)

O objetivo deste trabalho foi relatar a ocorrência de Austrodiplostomum spp. nos olhos e cérebros de Acaronia nassa, Caquetaia spectabilis, Satanoperca acuticeps, Curimatella sp. e Crenicichla marmorata em um lago do rio Amazonas no estado do Pará (Brasil). Dos 49 peixes examinados, 10,2% foram parasitados por metacercárias de Austrodiplostomum spp., A. nassa sendo o hospedeiro com maior número de metacercárias. Em cinco espécies de peixes examinadas, foram coletadas 51 metacercárias, sendo 45 encontradas nos olhos e 6 na caixa craniana. Nos olhos, as metacercárias estavam livres e ativas no humor vítreo, mas nenhuma opacificação foi observada. No cérebro, as metacercárias também eram livres e ativas, localizadas principalmente abaixo do encéfalo, no assoalho do crânio, na altura dos lobos oftálmicos e próximo ao nervo óptico. Em observações laboratoriais, no entanto, o peixe infectado não apresentou distúrbios comportamentais, o que pode estar relacionado ao baixo nível de parasitismo. Este foi o primeiro relato de Austrodiplostomum spp. em C. spectabilis, S. acuticeps, Curimatella sp., C. marmorata e A. nassa.(AU)

Metacercariae of Austrodiplostomum spp. (Digenea: Diplostomidae) infecting the eyes and brains of fish in Brazilian Amazon / Metacercaria de Austrodiplostomum spp. (Digenea: Diplostomidae) infectando olhos e cérebros de peixes na Amazônia Brasileira

The aim of this paper was to report the occurrence of Austrodiplostomum spp. in the eyes and brain of Acaronia nassa, Caquetaia spectabilis, Satanoperca acuticeps, Curimatella sp. and Crenicichla marmorata in a lake of the Amazon River system in the state of Pará (Brazil). Of 49 fish examined, 10.2% were parasitized by Austrodiplostomum spp. metacercariae, and A. nassa was the host with higher number of metacercariae. In five examined fish species, a total of 51 metacercariae were collected, with 45 found in the eyes and 6 in the cranial vault. In the eyes, the metacercariae were free and active in the vitreous humor, but no opacification was observed. In the brain, the metacercariae were also free and active, and located mainly below the encephalon, on the cranial floor, at the height of the ophthalmic lobes and near the optic nerve. In laboratory observations, however, the infected fish did not exhibit any behavioral disorders, and this may be related to the low level of parasitism. This was the first report of this digenean for C. spectabilis, S. acuticeps, Curimatella sp., C. marmorata and A. nassa.(AU)

O objetivo deste trabalho foi relatar a ocorrência de Austrodiplostomum spp. nos olhos e cérebros de Acaronia nassa, Caquetaia spectabilis, Satanoperca acuticeps, Curimatella sp. e Crenicichla marmorata em um lago do rio Amazonas no estado do Pará (Brasil). Dos 49 peixes examinados, 10,2% foram parasitados por metacercárias de Austrodiplostomum spp., A. nassa sendo o hospedeiro com maior número de metacercárias. Em cinco espécies de peixes examinadas, foram coletadas 51 metacercárias, sendo 45 encontradas nos olhos e 6 na caixa craniana. Nos olhos, as metacercárias estavam livres e ativas no humor vítreo, mas nenhuma opacificação foi observada. No cérebro, as metacercárias também eram livres e ativas, localizadas principalmente abaixo do encéfalo, no assoalho do crânio, na altura dos lobos oftálmicos e próximo ao nervo óptico. Em observações laboratoriais, no entanto, o peixe infectado não apresentou distúrbios comportamentais, o que pode estar relacionado ao baixo nível de parasitismo. Este foi o primeiro relato de Austrodiplostomum spp. em C. spectabilis, S. acuticeps, Curimatella sp., C. marmorata e A. nassa.(AU)

A rare retrobulbar and chiasmal meningioma in a dog / Meningioma raro retrobulbar e de quiasma óptico em cão

A 14-year-old female Dachshund was referred to a veterinary hospital with a history and signalment of head pressing, compulsive walking, and right circling. At ophthalmologic examination, a mature cataract and absence of photomotor reflex in the right eye were observed. The neurological exam revealed multifocal encephalic signs. At necropsy, a conical solid tan mass was observed involving the right optic nerve throughout its extension to the optic chiasm. Histopathological findings confirmed a retrobulbar papillary meningioma, considered rare and seldom included as differential diagnosis in patients with neurological signs.(AU)

Uma fêmea Dachshund de 14 anos de idade foi encaminhada para um hospital veterinário universitário com histórico e manifestação de head pressing, andar compulsivo e em círculos para o lado direito. No exame oftalmológico foi diagnosticado catarata matura bilateral e ausência de reflexo fotomotor pupilar no olho direito. O exame neurológico revelou sinais encefálicos multifocais. Na necropsia, uma massa sólida cônica, branco-amarelada, foi observada envolvendo o nervo óptico em toda a sua extensão até o quiasma óptico. O exame histopatológico confirmou diagnóstico de meningioma papilar retrobulbar, considerado raro e pouco incluído no diagnóstico diferencial de pacientes com sinais neurológicos.(AU)

Contrast-enhanced ocular ultrasonography in brachycephalic dogs

Background: Contrast Enchantment Ultrasonography (CEUS) allows for detection of vascular flows that are difficult to detect with traditional methods. There were no reports found in the literature of the use of CEUS to evaluate the vascular pattern of the eye of brachycephalic dogs. The objective of this paper is to describe ultrasound findings observed in the eyes of healthy brachycephalic dogs subjected to CEUS.Materials, Methods & Results: Thirty adult brachycephalic dogs were subjected to physical, laboratorial, and ophthalmic examination. The eye structures were evaluated using CEUS after intravenous administration of Sonovue®. Contrast enhancement was seen in 52 eyes with a homogeneous and centrifugal filling pattern. Structures adequately enhanced consisted of the optic nerve, the retina-choroid-sclera complex (RCSC), and the ciliary body. The optic nerve was hyperenhanced and the other structures were isoenhanced. The wash-in time, peak enhancement time, and wash-out time were similar for both right and left eyes. Mean values and standard deviation were calculated for contrast wash-in time, peak enhancement time, and wash-out time in the optic nerve, RCSC, and ciliary body.Discussion: Ultrasound is an important diagnostic resource for veterinary ophthalmology and provides relevant information for the detection of pathological conditions of the eyes of animals. The contrast-enhanced ultrasound allows evaluation of tissues at the capillary level (macro and microcirculation), complementing the vascular ultrasound scan. This study brings original information on contrast-enhanced ultrasound findings for evaluation of eyes in dogs, creating novel diagnostic possibilities for the use of this imaging technique in veterinary ophthalmology.[...]

Contrast-enhanced ocular ultrasonography in brachycephalic dogs

Background: Contrast Enchantment Ultrasonography (CEUS) allows for detection of vascular flows that are difficult to detect with traditional methods. There were no reports found in the literature of the use of CEUS to evaluate the vascular pattern of the eye of brachycephalic dogs. The objective of this paper is to describe ultrasound findings observed in the eyes of healthy brachycephalic dogs subjected to CEUS.Materials, Methods & Results: Thirty adult brachycephalic dogs were subjected to physical, laboratorial, and ophthalmic examination. The eye structures were evaluated using CEUS after intravenous administration of Sonovue®. Contrast enhancement was seen in 52 eyes with a homogeneous and centrifugal filling pattern. Structures adequately enhanced consisted of the optic nerve, the retina-choroid-sclera complex (RCSC), and the ciliary body. The optic nerve was hyperenhanced and the other structures were isoenhanced. The wash-in time, peak enhancement time, and wash-out time were similar for both right and left eyes. Mean values and standard deviation were calculated for contrast wash-in time, peak enhancement time, and wash-out time in the optic nerve, RCSC, and ciliary body.Discussion: Ultrasound is an important diagnostic resource for veterinary ophthalmology and provides relevant information for the detection of pathological conditions of the eyes of animals. The contrast-enhanced ultrasound allows evaluation of tissues at the capillary level (macro and microcirculation), complementing the vascular ultrasound scan. This study brings original information on contrast-enhanced ultrasound findings for evaluation of eyes in dogs, creating novel diagnostic possibilities for the use of this imaging technique in veterinary ophthalmology.[...](AU)

Acoustic radiation force impulse elastography of the eyes of brachycephalic dogs / Elastografia acoustic radiation force impulse dos olhos de cães braquicefálicos

Eyes from brachycephalic dogs were studied by acoustic radiation force impulse (ARFI) elastography to establish quantitative and qualitative reference values related to the shape and rigidity of some ocular structures. Eighty-four eyes from 42 adult brachycephalic dogs were included in this study. Animals were subjected to physical, laboratory, and ophthalmic examinations. Following confirmation of good health, the dogs were subjected to ultrasonography and ARFI elastography, emphasizing the optic nerve, ciliary body, and lens. On qualitative elastography, homogeneous characteristics were observed on the ciliary body and optic nerve. Aqueous and vitreous humors were visualized as mosaic-like images. Quantitative elastography showed the mean optic nerve shear wave velocity (SWV) was 1.01±0.27m/s, temporal ciliary body was 0.91±0.24m/s, and nasal ciliary body was 0.91±0.3m/s. The SWV of the lens values were out of range, this value was not detectable by this software. Elastography has proved to be a non-invasive procedure and feasible in dogs. The establishmentof the parameters of degree of rigidity of ocular structures will serve as a baseline for animals with eye disorders. Results may be extrapolated to primary research on the applicability of ARFI in the evaluation of ocular bulb in humans.(AU)

Estruturas oculares de cães braquicéfalos foram estudadas por elastografia acoustic radiation force impulse (ARFI) para estabelecer valores quantitativos e qualitativos de referência relacionados com a forma e a rigidez de algumas estruturas oculares. Foram avaliados 84 olhos de 42 cães braquicéfalos neste estudo. Os animais foram submetidos aos exames físico, laboratorial e aos exames oftalmológicos. Após a confirmação da sanidade dos pacientes, os cães foram submetidos à ultrassonografia e à elastografia ARFI, enfatizando-se o nervo óptico, o corpo ciliar e a lente. Para elastografia qualitativa, foram observadas características homogêneas no corpo ciliar e no nervo óptico. Os humores aquoso e vítreo foram visibilizados como imagens tipo mosaico. A elastografia quantitativa demonstrou velocidades de cisalhamento para nervo óptico de 1,01±0,27m/s, para corpo ciliar temporal de 0,91±0,24m/s e para corpo ciliar nasal de 0,91±0,3m/s. Valores dessas velocidades para lentes apresentaram-se fora do intervalo: X.XXm/s. A elastografia provou ser um procedimento não invasivo e viável para cães. Estabelecidos os parâmetros do grau de rigidez das estruturas oculares, futuramente tais dados servirão como padrão para avaliação de animais com os distúrbios oculares. Os resultados podem ser extrapolados para a pesquisa primária sobre a aplicabilidade da ARFI na avaliação do bulbo ocular em seres humanos.(AU)

Acoustic radiation force impulse elastography of the eyes of brachycephalic dogs / Elastografia acoustic radiation force impulse dos olhos de cães braquicefálicos

Eyes from brachycephalic dogs were studied by acoustic radiation force impulse (ARFI) elastography to establish quantitative and qualitative reference values related to the shape and rigidity of some ocular structures. Eighty-four eyes from 42 adult brachycephalic dogs were included in this study. Animals were subjected to physical, laboratory, and ophthalmic examinations. Following confirmation of good health, the dogs were subjected to ultrasonography and ARFI elastography, emphasizing the optic nerve, ciliary body, and lens. On qualitative elastography, homogeneous characteristics were observed on the ciliary body and optic nerve. Aqueous and vitreous humors were visualized as mosaic-like images. Quantitative elastography showed the mean optic nerve shear wave velocity (SWV) was 1.01±0.27m/s, temporal ciliary body was 0.91±0.24m/s, and nasal ciliary body was 0.91±0.3m/s. The SWV of the lens values were out of range, this value was not detectable by this software. Elastography has proved to be a non-invasive procedure and feasible in dogs. The establishmentof the parameters of degree of rigidity of ocular structures will serve as a baseline for animals with eye disorders. Results may be extrapolated to primary research on the applicability of ARFI in the evaluation of ocular bulb in humans.(AU)

Estruturas oculares de cães braquicéfalos foram estudadas por elastografia acoustic radiation force impulse (ARFI) para estabelecer valores quantitativos e qualitativos de referência relacionados com a forma e a rigidez de algumas estruturas oculares. Foram avaliados 84 olhos de 42 cães braquicéfalos neste estudo. Os animais foram submetidos aos exames físico, laboratorial e aos exames oftalmológicos. Após a confirmação da sanidade dos pacientes, os cães foram submetidos à ultrassonografia e à elastografia ARFI, enfatizando-se o nervo óptico, o corpo ciliar e a lente. Para elastografia qualitativa, foram observadas características homogêneas no corpo ciliar e no nervo óptico. Os humores aquoso e vítreo foram visibilizados como imagens tipo mosaico. A elastografia quantitativa demonstrou velocidades de cisalhamento para nervo óptico de 1,01±0,27m/s, para corpo ciliar temporal de 0,91±0,24m/s e para corpo ciliar nasal de 0,91±0,3m/s. Valores dessas velocidades para lentes apresentaram-se fora do intervalo: X.XXm/s. A elastografia provou ser um procedimento não invasivo e viável para cães. Estabelecidos os parâmetros do grau de rigidez das estruturas oculares, futuramente tais dados servirão como padrão para avaliação de animais com os distúrbios oculares. Os resultados podem ser extrapolados para a pesquisa primária sobre a aplicabilidade da ARFI na avaliação do bulbo ocular em seres humanos.(AU)

Biometric, B-mode and color Doppler ultrasound assessment of eyes in healthy dogs / Avaliação biométrica, ultrassonográfica em modo-B e por Doppler colorido ocular de cães hígidos

B-scan ultrasonography is an important diagnostic tool that allows characterization of internal organ anatomy and, when complemented by Doppler ultrasound, allows vascular hemodynamic assessment, increasing the diagnostic accuracy. Thus, the aim of the present study was the B-scan ultrasound characterization and measurement of the eyeball segments and assessment of the external ophthalmic artery by color and pulsed Doppler. Sixty eyeballs were assessed from 30 dogs of different breeds using an 8.5MHz microconvex transductor. First, biometry was performed by B-scan of the following segments: axial length (M1), anterior chamber depth (M2), lens thickness (M3), lens length (M4), vitreous chamber depth (M5), optical disc length (M6) and optic nerve diameter (M7). Colored Doppler identified the external ophthalmic article and pulsed Doppler assessed its flow, and the following were measured: systolic peak velocity (VPS), final diastolic velocity (VDF), resistivity index (IR) and pulse index (IP). No statistical difference was observed for the biometric values of the eye segments between the right and left eyes (p>0.05). The vitreous chamber depth (M5) was shown to be the biometric variable with greatest bilateral symmetry, varying from 0.79 to 0.87cm and 0.78 to 0.86cm for the right and left eye, respectively. The ophthalmic artery was visualized over the optic nerve towards the eyeball, with flow stained red. There was no significant statistical difference between the Doppler velocimetric values for the ophthalmic artery between the right and left eye of the animals assessed (p>0.05). The mean resistivity index (RI) showed average values equal to 0.63±0.03, bilaterally. The mean base velocity was 17.50cm/s and 18.18cm/s at the systolic peak and 6.21cm/s and 6.68cm/s at the end of the diastole, for the right and left eyes respectively. The anatomic, biometric and hemodynamic characterization using the ultrasound B-scan and the...(AU)

O exame ultrassonográfico modo-B é uma importante ferramenta diagnóstica que permite caracterizar a anatomia interna dos órgãos e, complementada pelo exame modo Doppler, possibilita realizar a avaliação hemodinâmica vascular, aumentando a acurácia diagnóstica. Desta forma, este trabalho teve como objetivo a caracterização ultrassonográfica e mensuração dos segmentos do bulbo ocular modo-B, assim como a avaliação da artéria oftálmica externa pelo Doppler colorido e pulsado. Foram avaliados 60 bulbos oculares de 30 cães de diferentes raças utilizando transdutor microconvexo de 8,5MHz. Inicialmente foi realizada biometria por meio do exame em modo-B dos seguintes seguimentos: comprimento axial (M1), profundidade da câmara anterior (M2), espessura da lente (M3), comprimento da lente (M4), profundidade da câmara vítrea (M5), comprimento do disco óptico (M6) e diâmetro do nervo óptico (M7). A artéria oftálmica externa foi identificada pelo Doppler colorido e seu fluxo foi avaliado por meio do Doppler pulsado, sendo mensurados: velocidade do pico sistólico (VPS), velocidade diastólica final (VDF), índice de resistividade (IR) e índice de pulsatilidade (IP). Não foi verificada diferença estatística para os valores biométricos dos seguimentos oculares entre os olhos direito e esquerdo (p>0,05). A profundidade da câmera vítrea (M5), mostrou-se a variável biométrica com maior simetria bilateral, variando entre 0,79 a 0,87cm e 0,78 a 0,86cm para o olho direito e esquerdo, respectivamente. A artéria oftálmica foi visibilizada sobre o nervo óptico em direção ao bulbo ocular, com fluxo marcado em vermelho. Não houve diferença estatística significativa entre os valores Dopplervelocimétricos da artéria oftálmica entre do olho direito e esquerdo dos animais avaliados (p>0.05). O índice de resistividade (IR) médio evidenciou valores médios sendo igual a 0,63±0,03, bilateralmente. A velocidade basal média foi 17,50cm/s e 18,18cm/s no pico sistólico e 6,21cm/s e 6,68cm/s no...(AU)

Biometric, B-mode and color Doppler ultrasound assessment of eyes in healthy dogs / Avaliação biométrica, ultrassonográfica em modo-B e por Doppler colorido ocular de cães hígidos

B-scan ultrasonography is an important diagnostic tool that allows characterization of internal organ anatomy and, when complemented by Doppler ultrasound, allows vascular hemodynamic assessment, increasing the diagnostic accuracy. Thus, the aim of the present study was the B-scan ultrasound characterization and measurement of the eyeball segments and assessment of the external ophthalmic artery by color and pulsed Doppler. Sixty eyeballs were assessed from 30 dogs of different breeds using an 8.5MHz microconvex transductor. First, biometry was performed by B-scan of the following segments: axial length (M1), anterior chamber depth (M2), lens thickness (M3), lens length (M4), vitreous chamber depth (M5), optical disc length (M6) and optic nerve diameter (M7). Colored Doppler identified the external ophthalmic article and pulsed Doppler assessed its flow, and the following were measured: systolic peak velocity (VPS), final diastolic velocity (VDF), resistivity index (IR) and pulse index (IP). No statistical difference was observed for the biometric values of the eye segments between the right and left eyes (p>0.05). The vitreous chamber depth (M5) was shown to be the biometric variable with greatest bilateral symmetry, varying from 0.79 to 0.87cm and 0.78 to 0.86cm for the right and left eye, respectively. The ophthalmic artery was visualized over the optic nerve towards the eyeball, with flow stained red. There was no significant statistical difference between the Doppler velocimetric values for the ophthalmic artery between the right and left eye of the animals assessed (p>0.05). The mean resistivity index (RI) showed average values equal to 0.63±0.03, bilaterally. The mean base velocity was 17.50cm/s and 18.18cm/s at the systolic peak and 6.21cm/s and 6.68cm/s at the end of the diastole, for the right and left eyes respectively. The anatomic, biometric and hemodynamic characterization using the ultrasound B-scan and the Doppler modalities permitted the ultrasonographic and Doppler velocimetric assessment of the eyeball components in dogs of different breeds, and it can be used in ophthalmic clinical routine to identify eye pathologies.

O exame ultrassonográfico modo-B é uma importante ferramenta diagnóstica que permite caracterizar a anatomia interna dos órgãos e, complementada pelo exame modo Doppler, possibilita realizar a avaliação hemodinâmica vascular, aumentando a acurácia diagnóstica. Desta forma, este trabalho teve como objetivo a caracterização ultrassonográfica e mensuração dos segmentos do bulbo ocular modo-B, assim como a avaliação da artéria oftálmica externa pelo Doppler colorido e pulsado. Foram avaliados 60 bulbos oculares de 30 cães de diferentes raças utilizando transdutor microconvexo de 8,5MHz. Inicialmente foi realizada biometria por meio do exame em modo-B dos seguintes seguimentos: comprimento axial (M1), profundidade da câmara anterior (M2), espessura da lente (M3), comprimento da lente (M4), profundidade da câmara vítrea (M5), comprimento do disco óptico (M6) e diâmetro do nervo óptico (M7). A artéria oftálmica externa foi identificada pelo Doppler colorido e seu fluxo foi avaliado por meio do Doppler pulsado, sendo mensurados: velocidade do pico sistólico (VPS), velocidade diastólica final (VDF), índice de resistividade (IR) e índice de pulsatilidade (IP). Não foi verificada diferença estatística para os valores biométricos dos seguimentos oculares entre os olhos direito e esquerdo (p>0,05). A profundidade da câmera vítrea (M5), mostrou-se a variável biométrica com maior simetria bilateral, variando entre 0,79 a 0,87cm e 0,78 a 0,86cm para o olho direito e esquerdo, respectivamente. A artéria oftálmica foi visibilizada sobre o nervo óptico em direção ao bulbo ocular, com fluxo marcado em vermelho. Não houve diferença estatística significativa entre os valores Dopplervelocimétricos da artéria oftálmica entre do olho direito e esquerdo dos animais avaliados (p>0.05). O índice de resistividade (IR) médio evidenciou valores médios sendo igual a 0,63±0,03, bilateralmente. A velocidade basal média foi 17,50cm/s e 18,18cm/s no pico sistólico e 6,21cm/s e 6,68cm/s no final da diástole, para os olhos direito e esquerdo, respectivamente. A caracterização anatômica, biométrica e hemodinâmica utilizando o exame ultrassonográfico modo-B e as modalidades do Doppler permitiram a avaliação ultrassonográfica e Dopplervelocimétrica dos componentes do bulbo ocular nos cães de diferentes raças, podendo ser utilizados na rotina clínica oftalmológica para identificação de patologias oculares.

Identification of Neospora caninumin aborted bovine fetuses of southern Chile

The aim of this study was to identify Neospora caninum in histologic sections of brain and optic nerve of aborted bovine fetuses. Sections of these tissues from 296 aborted bovine fetuses from Southern Chile, submitted between 2000 and 2010, to the Instituto de Patología Animal of the Universidad Austral de Chile were analyzed. Forty-four (14.9%) fetuses had microscopic lesions compatible with bovine neosporosis, including gliosis, necrosis, intralesional protozoan cysts and neuritis of optic nerves. N. caninum was identified by immunohistochemistry in brain sections of 27 cases (9.1%) with compatible lesions. Positive immunostaining was also found in the optic nerves of 13 cases (4.4%) with neuritis. N. caninum DNA was identified by PCR in brain sections in 31 cases (10.5%). In total, 36 cases (12.2%) were positive by either technique. Phylogenetic analysis of the ITS1 gene sequence of N. caninum revealed a high degree of conservation among different isolates. This is the first report of N. caninum-associated optic neuritis in cattle and also the first report of confirmed bovine abortion associated with this parasite in Chile.

Identification of Neospora caninumin aborted bovine fetuses of southern Chile

The aim of this study was to identify Neospora caninum in histologic sections of brain and optic nerve of aborted bovine fetuses. Sections of these tissues from 296 aborted bovine fetuses from Southern Chile, submitted between 2000 and 2010, to the Instituto de Patología Animal of the Universidad Austral de Chile were analyzed. Forty-four (14.9%) fetuses had microscopic lesions compatible with bovine neosporosis, including gliosis, necrosis, intralesional protozoan cysts and neuritis of optic nerves. N. caninum was identified by immunohistochemistry in brain sections of 27 cases (9.1%) with compatible lesions. Positive immunostaining was also found in the optic nerves of 13 cases (4.4%) with neuritis. N. caninum DNA was identified by PCR in brain sections in 31 cases (10.5%). In total, 36 cases (12.2%) were positive by either technique. Phylogenetic analysis of the ITS1 gene sequence of N. caninum revealed a high degree of conservation among different isolates. This is the first report of N. caninum-associated optic neuritis in cattle and also the first report of confirmed bovine abortion associated with this parasite in Chile.(AU)

Parâmetros eletrorretinográficos e avaliação histomorfométrica da retina de três espécies de morcegos insetívoros (Mammalia: Chiroptera)

As informações referentes ao sistema visual dos morcegos são limitadas, sobretudo, referente as espécies encontradas no Brasil. Assim, objetivou-se analisar e comparar a morfofisiologia da retina e sensibilidade espectral de três espécies de morcegos insetívoros Cynomops planirostris (Molossidae), Rhynchonycteris naso (Emballonuridae) e Myotis lavali (Vespertilionidae), provenientes da zona urbana de Recife PE, através de parâmetros eletrofisiológicos e histomorfométricos. Os morcegos foram capturados no campus da Universidade Federal Rural de Pernambuco, Dois Irmãos, Recife PE. O exame eletrorretinográfico de campo total verificou a resposta fotópica da retina de forma multifrequencial nos seguintes comprimentos de ondas (405 nm, 470 nm, 527 nm, 591 nm, 626 nm e 940 nm) de (3 fêmeas da espécie R. naso, 1 macho da espécie C. planirostris e 3 fêmeas e 1 macho da espécie M. lavali). Além disso, foi realizada a análise histomorfométrica da retina de 05 indivíduos adultos da espécie R. naso, 06 morcegos adultos da espécie C. planirostris e 05 espécimes adultos da espécie M. lavali. Os morcegos foram submetidos ao processo de eutanásia. Os olhos foram enucleados, processados seguindo técnica histológica de rotina, cortados e as lâminas histológicas produzidas foram coradas por Hematoxilina Eosina e analisadas em microscópio óptico. Portanto, foi mensurado a espessura total da retina (excluindo o epitélio pigmentar) e de cinco camadas retinianas: (FT) segmentos externos e internos dos fotorreceptores; (NE) camada nuclear externa; (NI) camada nuclear interna; (PI) camada plexiforme interna e (FN) camada de fibras nervosas. As mensurações histomorfométricas de cada parâmetro foram realizadas em oito áreas distintas da retina de cada animal. Portanto, quatro áreas de análise foram estabelecidas na região dorsal da retina: (0,2 mm); (0,4 mm); (0,6 mm) e (0,8 mm) depois do nervo óptico e quatro áreas na região ventral da retina: (0,2 mm); (0,4 mm); (0,6 mm) e (0,8 mm) depois do nervo óptico. Os resultados foram comparados entre as regiões ventral e dorsal da retina, entre as áreas central e periférica, e além disso os resultados de cada análise foram comparados entre as três espécies. Nos registros realizados nos exames fotópicos foi possível identificar a presença e o comportamento das ondas a e b para as três espécies morcegos. Os testes de ERG-ct multifrequencial mostraram que as três espécies de morcegos insetívoras apresentam respostas a todos os estímulos viii analisados em diferentes comprimentos de onda desde o ultravioleta (405 nm) ao vermelho (626 nm). Além disso, a espécie R. naso foi a única que apresentou resposta ao comprimento de onda infravermelho (940 nm). As 10 camadas da retina de organização celular foram identificadas nas três espécies de morcegos. Na primeira análise histomorfométrica, verificou-se que maiores médias dos parâmetros analisados foram encontrados na região ventral da retina das espécies C. planirostris e R. naso, enquanto a espécie M. lavali não apresentou diferenças significativas entre essas duas regiões da retina. As mensurações da área central apresentaram-se significativamente maiores em comparação com periférica da retina para as três espécies na maioria dos parâmetros. Quando comparado entre as três espécies, a espécie C. planirostris exibiu as maiores médias em comparação com as outras duas espécies, com exceção da camada de fibras nervosas que mostrou-se mais espessa na espécie R. naso e a camada nuclear externa, no qual foi verificado as maiores médias para a espécie M. lavali. Assim, esse trabalho amplia o conhecimento a respeito do processo evolutivo dos pigmentos visuais encontrados em morcegos, no qual sugerimos a presença e devido funcionamento das duas opsinas (S-) e (L-) em C. planirostris, R. naso e M. lavali, além de confirmar a percepção espectral do comprimento UV pelas três espécies insetívoras estudadas. Adicionalmente, a percepção do espectro infravermelho pela espécie R. naso abre uma nova discussão sobre a sensibilidade visual em morcegos, no qual futuras investigações devem ser realizadas para aprimorar os conhecimentos em relação a importância da manutenção dessa característica nessa espécie. Além disso, apesar da espécie C. planirostris mostrar as maiores médias dos parâmetros mensurados, estes valores estão diretamente relacionados apenas ao tamanho do bulbo ocular e consequentemente ao aporte corpóreo dos animais. Por outro lado, os dados hismorfométricos da retina sugerem que a espécie R. naso possua uma maior capacidade visual em comparação com as outras duas.

Information about the visual system of bats is limited, especially regarding the species found in Brazil. Thus, this study aimed to analyze and compare the retinal morphophysiology and spectral sensitivity of three insectivorous bats of the species Cynomops planirostris (Molossidae), Rhynchonycteris naso (Emballonuridae) and Myotis lavali (Vespertilionidae) from the urban area of Recife - PE, by electrophysiological and histomorphometric parameters. Bats were captured at the Federal Rural University of Pernambuco, Dois Irmãos, Recife PE. Full-field electroretinographic evaluated the photopic response of the retina at different wavelengths (405 nm, 470 nm, 527 nm, 591 nm, 626 nm and 940 nm) of (3 females of the species R. naso, 1 male of the species C. planirostris and 3 fameles and 1 male of the species M. lavali). Furthermore, this study aimed to describe the microscopic structure of the retina in three species of insectivorous bats (06 adult bats of the species Cynomops planirostris), (05 adult individuals of the species Rhynchonycteris naso) and (05 adult specimens of the species Myotis lavali) using histomorphometric measurements. The bats were submitted to euthanasia. The eyes were enucleated, processed following routine histological technique, cut and then the histological slides produced were stained with Hematoxylin Eosin and analyzed under an optical microscope. Therefore, the total thickness of the retina (excluding the retinal pigment epithelium) and five retinal layers was measured: (FT) outer and inner segments of photoreceptors; (NE) outer nuclear layer; (NI) inner nuclear layer; (PI) inner plexiform layer and (FN) nerve fiber layer. The histomorphometric measurements of each parameter were conducted in eight distinct areas of the retina of each animal four areas of analysis were established in the dorsal region of the retina: (0.2 mm); (0.4 mm); (0.6 mm) and (0.8 mm) after the optic nerve and four areas in the ventral region of the retina: (0.2 mm); (0.4 mm); (0.6 mm) and (0.8 mm) after the optic nerve. The results of the measurements were compared between the ventral and dorsal regions of the retina, between the central and peripheral areas, and furthermore, the results of each analysis were compared between the three species. In the records carried out from photopic examinations, it was possible to identify the presence and behavior of waves a and b for the three bat species. Full-field electroretinography showed that the three bat species responded to all stimuli analyzed at different wavelengths from ultraviolet (405 nm) to red (626 nm). Furthermore, R. naso was the only species that x showed response to the infrared wavelength (940 nm). The 10 retinal layers of cell organization were identified in the three species bats. In the first histomorphometric analysis, it was found that the highest means of the parameters were found in the ventral region of the retina of the species C. planirostris and R. naso, while the species M. lavali did not show significant differences between these two regions of the retina. The measurements of the central area were significantly higher compared to the peripheral retina for the three species in most parameters. When compared between the three species, the species C. planirostris exhibited the highest means compared to the other two species, with the exception of the nerve fiber layer, which was thicker in the species R. naso, and the outer nuclear layer, in which the highest average was observed for the species M. lavali. Thus, this study expands the knowledge about the evolutionary process of visual pigments in bats, in which we suggest the presence and functioning of the two opsins (S-) and (L-) in C. planirostris, R. naso and M. lavali, in addition to confirming the spectral perception of UV wavelength by the three insectivorous species studied. Moreover, the perception of the infrared spectrum by the species R. naso opens a new discussion on visual sensitivity in bats, and future investigations must be carried out to improve knowledge regarding the importance of maintaining this characteristic in this species. Furthermore, despite the species C. planirostris showing the highest averages of the measured parameters, these values are directly related only to the size of the eye and consequently the size of their bodies. On the other hand, the retinal hismorphometric data suggest that the species R. naso show a greater visual capacity compared to the other two.

Glaucoma, apoptosis y sildenafil: comprensión de una enfermedad sin solución y un posible enfoque de tratamiento / Glaucoma, apoptose e sildenafil: compreensão de uma doença sem solução e uma possível abordagem de tratamento / Glaucoma, apoptosis and sildenafil: comprehension of a disease without solution and a possible approach of treatment

Millones de pacientes con glaucoma pierden la visión, por lo que es una necesidad para desarrollar terapias neuroprotectoras que pueden utilizarse en conjunción con medicamentos hipotensores, para prevenir la muerte de las células ganglionares de la retina (CGR). Los recientes avances en la comprensión de la fisiopatología de glaucoma es un factor clave en la patogénesis de la neuropatía glaucomatosa. Con base en los hallazgos en enfermedades similares, la hipótesis de que la mejora del flujo sanguíneo de la retina nervio óptico puede dar lugar a una protección significativa en CGR y prevenir la pérdida de visión en el glaucoma. Sildenafil, un fármaco vasodilatador que inhibe la PDE5, lo que aumenta los niveles de cGMP y la prolongación de sus efectos, y se ha demostrado que mejora la supervivencia de diversas lesiones degenerativas. Esta breve revisión resume los avances más importantes que tenían el conocimiento de esta enfermedad y su posible tratamiento.(AU)

Milhões de pacientes com glaucoma irão perder a visão, tornando-se uma necessidade desenvolver terapias neuroprotetoras que possam ser usadas, em conjunção com medicamentos hipotensores, para impedir a morte de células ganglionares da retina (CGR). Recentes avanços na compreensão da fisiopatologia do glaucoma são um fator chave na patogênese da neuropatia glaucomatosa. Com base nos achados em doenças semelhantes, a hipótese de que melhorando o fluxo sanguíneo do nervo óptico da retina possa resultar em uma proteção significativa nas CGR e prevenir a perda da visão no glaucoma. O sildenafil, uma droga vasodilatadora que inibe PDE5, aumentando assim os níveis de cGMP e prolongando seus efeitos, sendo que foi demonstrado melhorar a sobrevivência de várias lesões degenerativas. Esta breve revisão resume alguns dos avanços mais importantes que tiveram no entendimento sobre esta doença e um possível tratamento.(AU)

As millions of glaucoma patients lose sight, it has become accepted that there is a need to develop neuroprotective therapies that can be used, in conjunction with hypotensive drugs, to prevent retinal ganglion cell (RGC) death. Recent advances in the understanding of the pathophysiology of glaucoma is a key factor in the pathogenesis of glaucomatous neuropathy. Based on findings in similar diseases, hypothesize that improving retinal and optic nerve blood flow can result in significant RGC protection and prevent vision loss in glaucoma. Sildenafil, a vasodilative drug that inhibits PDE5, thereby increasing cGMP levels and prolonging NO effects, has been shown to improve survival in several injury. This short review briefly summarizes some of the most important advances that have taken in the understand about this disease and a possible treatment.(AU)