Distrofia macular oculta / Occult macular dystrophy

Resumo Apresentamos um caso de distrofia macular oculta bilateral, em paciente de 70 anos com queixa de baixa acuidade visual progressiva, sem achados fundoscópicos ou angiográficos justificáveis. Foram realizados exames de imagem do sistema nervoso central que afastaram lesões expansivas e testes eletrofisiológicos que sugeriram diagnóstico.

Abstract We report a case of bilateral occult macular dystrophy in a 70-year-old woman with progressive low visual acuity, without justifiable fundoscopic or angiographic findings. Imaging tests were done to excluding expansive lesions and electrophysiological tests that suggested the diagnosis.

Electroretinography in eight species of neotropical deer / Eletrorretinografia em oito espécies de cervídeos neotropicais

The aim of this study was to establish normal baseline ERG values of 23 anesthetized deer belonging to 8 neotropical species (Mazama americana, Mazama nemorivaga, Mazama gouazoubira, Mazama nana, Mazama bororo, Ozotocerus bezoarticus, Odocoileus virginianus and Blastocerus dichotomus). Only right eyes were studied. Chemical restraint was performed using xylazine associated with ketamine, IM, for M. americana, M. gouazoubira, M. nemorivaga, M. nana, M. bororo, O. bezoarticus and O. virginianus. A combination of tiletamine/zolazepam diluted in xylazine 2% was used for B. dichotomus individuals. After 20min of dark adaptation, electroretinograms were obtained using a handheld electroretinography (ERG) machine using the QuickRetCheck Protocol at three different light intensities: 0.01cd.s/m2, 3cd.s/m2, and 10cd.s/m2. After light adaptation, photopic phase was recorded. A-wave amplitude recorded during pattern mixed rod/cone response in M. americana was significantly lower when compared to B. dichotomus. No other differences were observed between the species studied. ERG in Neotropical deer is applicable using a portable ERG system and did not show differences among species in relation to the retinal response at different light intensities. Therefore, the lifestyle of the species is more dictated by the selection pressure of the environment than by physiological factors.(AU)

Objetivou-se estabelecer valores de referência para eletrorretinografia (ERG) de 23 cervídeos anestesiados, de oito espécies neotropicais (Mazama americana, Mazama nemorivaga, Mazama gouazoubira, Mazama nana, Mazama bororo, Ozotocerus bezoarticus, Odocoileus virginianus e Blastocerus dichotomus). Somente os olhos direitos foram estudados. A contenção química foi realizada com cetamina/xilazina, IM, nas seguintes espécies: M. americana, M. gouazoubira, M. nemorivaga, M. nana, M. bororo, O. bezoarticus e O. virginianus. Para o B. dichotomus, foi utilizada a associação de tiletamina/zolazepam e xilazina. Após 20 minutos de adaptação ao escuro, os eletrorretinogramas foram obtidos com aparelho portátil de ERG, utilizando-se o protocolo "QuickRet Check", em três intensidades de luz: 0.01cd.s/m2, 3cd.s/m2 e 10cd.s/m2. Após adaptação à luz, realizou-se a fase fotóptica. Os valores para amplitude da onda A durante a resposta padrão mista de cones/bastonetes em M. americana foram significativamente menores quando comparados aos do B. dichotomus. Não foram observadas outras diferenças entre as espécies. A realização de ERG em cervídeos neotropicais é aplicável utilizando-se aparelho portátil e não demonstrou diferenças quanto à resposta retiniana a diferentes intensidades de luz. Dessa forma, o estilo de vida das espécies é ditado mais pela pressão de seleção do ambiente do que por fatores fisiológicos.(AU)

Benign familial fleck retina: multimodal imaging including optical coherence tomography angiography / Benign familial fleck retina: estudo multimodal incluindo OCT angiography

ABSTRACT This report presents multimodal imaging of a 27-year-old woman diagnosed with benign familial fleck retina (OMIM 228980), an uncommon disorder. Fundus photographs revealed retinal flecks that affected her post-equatorial retina but spared the macular area. Fundus autofluorescence and infrared imaging demonstrated a symmetrical pattern of yellow-white fleck lesions that affected both eyes. Her full-field electroretinogram and electrooculogram were normal. An optical coherence tomography B-scan was performed for both eyes, revealing increased thickness of the retinal pigmented epithelium leading to multiple small pigmented epithelium detachments. The outer retina remained intact in both eyes. Spectral-domain optical coherence tomography angiography with split-spectrum amplitude decorrelation algorithm and 3 × 3 mm structural en face optical coherence tomography did not show macular lesions. Benign familial fleck retina belongs to a heterogenous group of so-called flecked retina syndromes, and should be considered in patients with yellowish-white retinal lesions without involvement of the macula.

RESUMO O objetivo do presente relato é demonstrar um estudo multimodal de um paciente com diagnóstico de Benign Familial Fleck Retina (BFFR) (OMIM 228980), uma alteração retinana muito rara. Retinografia colorida demonstrou "flecks" na retina posterior ao equador, poupando mácula. Tanto autofluorescência quando imagem "infrared," nota-se padrão simétrico de lesões amareladas em ambos os olhos. Eletrorretinograma padrão de campo total e EOG não evidenciaram alterações. SD OCT B-scan demostrou pequenos e múltiplos descolamentos do epitélio pigmentado (EPR), com retina externa intacta em ambos os olhos. Angiografia por OCT com "split-spectrum amplitude decorrelation algorithm" e "structural" "en face" OCT 3 x 3 mm não apontaram anormalidades na mácula. BFFR pertence ao heterogêneo grupo chamado "flecked retina syndromes," devendo ser considerada em pacientes com flecks retinianos poupando mácula.

Retinal function in patients with the neuronal ceroid lipofuscinosis phenotype / Estudo da função retiniana em pacientes com o fenótipo da lipofuscinose ceróide neuronal

ABSTRACT Purpose: To analyze the clinical features, visual acuity, and full-field electroretinogram (ERG) findings of 15 patients with the neuronal ceroid lipofuscinosis (NCL) phenotype and to establish the role of ERG testing in NCL diagnosis. Methods: The medical records of five patients with infantile NCL, five with Jansky-Bielschowsky disease, and five with juvenile NCL who underwent full-field ERG testing were retrospectively analyzed. Results: Progressive vision loss was the initial symptom in 66.7% of patients and was isolated or associated with ataxia, epilepsy, and neurodevelopmental involution. Epilepsy was present in 93.3% of patients, of whom 86.6% presented with neurodevelopmental involution. Fundus findings ranged from normal to pigmentary/atrophic abnormalities. Cone-rod, rod-cone, and both types of dysfunction were observed in six, one, and eight patients, respectively. Conclusion: In our study, all patients with the NCL phenotype had abnormal ERG findings, and the majority exhibited both cone-rod and rod-cone dysfunction. We conclude that ERG is a valuable tool for the characterization of visual dysfunction in patients with the NCL phenotype and is useful for diagnosis.

RESUMO Objetivo: Analisar o quadro clínico, a acuidade visual e o eletrorretinograma de campo total (ERG) de 15 pacientes com o fenótipo da lipofuscinose ceróide neuronal (LCN), estabelecendo o papel do eletrorretinograma no seu diagnóstico. Métodos: Eletrorretinograma foi realizado em 5 pacientes com lipofuscinose ceróide neuronal infantil, 5 com doença de Jansky-Bielschowsky e 5 com lipofuscinose ceróide neuronal juvenil sendo feita uma análise retrospectiva dos registros médicos. Resultados: A perda progressiva da acuidade visual foi o sintoma inicial em 66,7%; isolada ou associada à ataxia, epilepsia e involução do desenvolvimento neuropsico motor. Epilepsia foi o sintoma inicial em 93,3% e 86,6% apresentaram involução do desenvolvimento neuropsicomotor. Achados fundoscópicos variaram de normal a alterações pigmentares/atróficas. Disfunção de cone-bastonete foi constatada em 6 pacientes, bastonete-cone em 1 e em 8 pacientes observou-se disfunção proporcional de ambos os sistemas. Conclusão: O eletrorretinograma foi alterado em todos os pacientes, e o achado mais frequente foi o comprometimento de cones e bastonetes. O eletrorretinograma constitui, portanto, uma ferramenta valiosa para caracterizar a disfunção visual em pacientes com o fenótipo da lipofuscinose ceróide neuronal, contribuindo para seu diagnóstico.

Structure-functional correlation using adaptive optics, OCT, and microperimetry in a case of occult macular dystrophy / Correlação de estrutura e função da retina utilizando óptica adaptativa, OCT e microperimetria em um caso de distrofia macular oculta

ABSTRACT We report retinal functional and structural changes of a 40-year-old man diagnosed with occult macular dystrophy. Comprehensive ophthalmological evaluation was performed, followed by spectral-domain optical coherence tomography (SD-OC - Heidelberg) and image acquisition using an adaptive optics (AO) camera (RTX1, Imagine Eyes) for photoreceptor density analysis. Functional tests included full-field ERG (ERG) and multifocal electroretinography (mfERG) (Diagnosys, LLC) and microperimetry with scanning laser ophthalmoscope (SLO) fixation controlled (MAIA, CenterVUE). OCT revealed a line of discontinuity corresponding to cone outer-segment photoreceptors associated with a loss of cone density, highlighted by a dark blue spot on the AO co ne-density map on the fovea in both eyes. Loss of central sensitivity was revealed using microperimetry; ERG was within the normal range, although the mfERG showed a reduced central response amplitude.

RESUMO Relatamos exames de função e estrutura retiniana de paciente masculino, de 40 anos, com diagnóstico clínico de Distrofia Macular Oculta (DMO). Avaliação oftalmológica completa foi seguida por tomografia de Coerência Óptica (SD-OCT - Heidelberg) e exame com câmara de fundo de olho com tecnologia "Adaptive Optics" (AO - RTX1, Imagine Eyes) para análise da densidade de fotorreceptores. Os exames funcionais incluíram: Eletroretinografia de campo total (ERG) e multifocal (mfERG) (Diagnosys - LLC) e microperimetria com controle de fixação (MAIA - CenterVUE). Os exames revelam descontinuidade da camada de fotorreceptores na região central da fóvea em ambos os olhos pelo SD-OCT em associação com perda de densidade no mosaico cones, representado por mancha azulada no mapa do AO. Os exames de função apresentam diminuição da acuidade visual (20/80; 20/50), redução de sensibilidade central na microperimetria. Como esperado, o ERG está dentro da normalidade, mas há redução da amplitude das respostas centrais do mfERG em ambos os olhos.

Full-field electroretinogram recorded with skin electrodes in normal adults / Eletrorretinograma de campo total registrado com eletrodos de pele em adultos normais

ABSTRACT Purpose: Alternative recording methods have been tested to allow the electroretinogram (ERG) recording in uncooperative patients and/or patients with palpebral alterations, including recordings with skin electrodes. The purpose of this study was to compare ERG recorded with skin electrodes and well-established microfiber electrodes and to determine normative values of ERG parameters for recording with skin electrodes. Methods: Fifty healthy volunteers (17-26 years; mean 20.63 ± 2.01 years) participated in the study. A gold disk skin electrode was placed on the lower orbital rim of a randomly chosen eye. On the contralateral eye, a microfiber electrode was positioned in the lower conjunctival sac. Gold disc electrodes were positioned at the ipsilateral outer canthus of both eyes acting as reference electrodes for the creation of a potential difference. Two ground electrodes were placed on the lobe of each ear. ERGs were recorded according to the International Society of Clinical Electrophysiology Visual (ISCEV) protocol using the VERIS 5.1.9 system for data acquisition and analysis. Results: Both types of electrodes showed similar wave response morphologies. The implicit time of responses between the two electrodes was comparable. On peak-to-peak amplitude, skin electrode recordings showed an amplitude reduction of 61.4% for rod responses, 61.5% for maximal responses, 46.2% for oscillatory potentials, 57.4% for cone responses, and 54.4% for 30Hz-flicker responses, when compared with microfiber electrode recordings. Based on these findings, normative values for peak-to-peak amplitude and implicit time to be used as a reference for ERGs recorded with skin electrodes were determined. Conclusions: ERGs recorded with skin electrodes presented lower peak-to-peak amplitude compared with microfiber electrodes. However, using appropriate normative values, skin electrodes may be useful for specific target populations such as uncooperative infants and/or patients with ocular surface alterations.

RESUMO Objetivo: O eletrorretinograma de campo total (ERG) em pacientes não colaborativos e/ou com alterações palpebrais pode ser registrado com diferentes métodos de captação de respostas, dentre eles os eletrodos de pele. O objetivo deste estudo foi comparar o eletroretinograma obtido com eletrodos de pele e eletrodos de microfibra, determinando valores normativos para os parâmetros registrados com eletrodos de pele. Métodos: Cinquenta voluntários saudáveis (17-26 anos; média 20,63 ± 2,01) participaram deste estudo. Um eletrodo de cúpula de ouro foi aderido à pele na margem orbital inferior de um dos olhos escolhido ao acaso. No olho contralateral, um eletrodo de microfibra foi posicionado no saco conjuntival inferior. Eletrodos de cúpula de ouro foram posicionados na região lateral de cada olho para a formação da diferença de potencial com o eletrodo ativo. Dois eletrodos terra foram posicionados no lobo de cada orelha. O eletrorretinograma foi registrado de acordo com o protocolo da ISCEV (Sociedade Internacional de Eletrofisiologia Visual), com o sistema VERIS 5.1.9 para aquisição e análise dos registros. Resultados: Os dois tipos de eletrodos apresentaram morfologias de onda similares. O tempo implícito das respostas foi comparável entre os dois tipos de eletrodo. Os registros feitos com eletrodo de pele quando comparados aos registros com eletrodos de microfibra mostraram reduções na amplitude das ondas, de 61,4% para resposta de bastonetes, 61,5% para resposta máxima, 46,2% para potenciais oscilatórios, 57,4% para resposta de cones, e 54,4% para flicker 30Hz. Baseado nestes resultados, foram determinados valores normativos para amplitude e tempo de implícito para ERGs obtidos com eletrodos de pele. Conclusões: ERGs registrados com eletrodos de pele apresentam respostas com amplitudes menores quando comparados aos registrados com eletrodos de microfibra. No entanto, usando valores normativos apropriados, os eletrodos de pele podem ser uma alternativa útil para populações especificas como pacientes não colaborativos e/ou com alterações palpebrais.

Is there a relationship between outer retinal destruction and choroidal changes in cone dystrophy? / Existe uma relação entre a destruição da retina externa e alterações da coroide em distrofia de cones?

ABSTRACT Purpose: The aim of the present study was to use enhanced depth imaging optical coherence tomography (EDI-OCT) to investigate choroidal changes in patients with cone dystrophy (CD) and to correlate these findings with clinical and electroretinography (ERG) findings. Methods: This case-control study included 40 eyes of 20 patients with CD and 40 eyes of 40 age- and refraction-matched healthy individuals. Choroidal thickness (CT) measurements were obtained under the foveal center and at 500 and 1,500 μm from the nasal and temporal regions to the center of the fovea, respectively. EDI-OCT and ERG data were analyzed, and the correlations of CT with the best-corrected visual acuity (BCVA) and the central foveal thickness (CFT) were evaluated. Results: The mean subfoveal CTs in the CD and control groups were 240.70 ± 70.78 and 356.18 ± 48.55 μm, respectively. The subfoveal CT was significantly thinner in patients with CD than in the controls (p<0.001). The patients with CD also had significantly thinner choroids than the controls at each measurement location relative to the fovea (p<0.001). The subfoveal CT in the CD group correlated with CFT (p=0.012), but no significant correlation was found between the subfoveal CT and BCVA or photopic ERG responses. Conclusions: The present study demonstrated a significant thinning of the choroid in patients with CD. EDI-OCT is a useful technique for describing the choroidal changes occurring in CD. Future studies investigating the association between choroidal changes and outer retinal destruction or the disease stage may provide a better understanding of the pathophysiology of CD.

RESUMO Objetivo: O objetivo deste estudo foi a utilização de imagens de tomografia de coerência óptica com profundidade aprimorada (EDI-OCT) para investigar alterações da coroide em pacientes com distrofia de cones (CD) e correlacionar esses achados com os achados clínicos e de eletrorretinografia (ERG). Métodos: Este estudo de caso-controle incluiu 40 olhos de 20 pacientes com CD e 40 olhos de 40 indivíduos saudáveis com idades e refração pareados. As medidas da espessura da coroide (CT) foram obtidas sob o centro foveal e a 500 μm e 1.500 μm de distância do centro da fóvea, nas regiões nasais e temporais. Dados de EDI-OCT e ERG foram analisados e as correlações do CT com a acuidade visual melhor corrigida (BCVA) e da espessura foveal central (CFT) foram realizadas. Resultados: As CTs subfoveais médias nos grupos CD e controle foram 240,70 ± 70,78 μm e 356,18 ± 48,55 μm, respectivamente. A CT subfoveal foi significativamente mais fina em pacientes com CD do que nos controles (p<0,001). Os com CD pacientes apresentaram também coroides significativamente mais finas do que os controles, em cada local de medição em relação à fóvea (p<0,001). A CT subfoveal no grupo CD se correlacionou com o CFT (p=0,012), mas nenhuma correlação significativa foi encontrada entre a CT subfoveal e a acuidade visual ou respostas fotópicas da ERG. Conclusões: O presente estudo demonstrou um afinamento significativo da coroide em pacientes com CD. A EDI-OCT é uma técnica útil para descrever as mudanças que ocorrem na coroide de pacientes com CD. Futuros estudos investigando a associação entre as alterações da coroide e a destruição da retina externa ou estágio da doença irão proporcionar uma melhor compreensão da fisiopatologia da CD.

The role of pattern-reversal electroretinography in the diagnosis of glaucoma / Importância do eletroretinograma de padrão reverso no diagnóstico do glaucoma

Pattern electroretinography is used to assess the function of the inner retinal layers, particularly the retinal ganglion cell layer, using a reversing checkerboard or grating pattern that maintains a constant overall mean luminance over time. A normal transient response comprises a positive component of the wave (P50) followed by a longer negative component of the wave (N95). Glaucomatous optic neuropathy causes progressive loss of retinal ganglion cells, potentially detectable as abnormalities on examination, particularly in the N95 component. Therefore, pattern electroretinography may be useful in the diagnosis and evaluation of glaucoma. The present article is an updated review of published data regarding the use of pattern electroretinography for the detection of glaucoma-induced retinal changes.

O eletroretinograma de padrão reverso é utilizado para avaliar a função das camadas internas da retina, particularmente a camada de células ganglionares retinianas, utilizando um estímulo em xadrez ou barras alternantes, mantendo constante o nível de contraste total. A resposta transiente normal é constituída por uma onda positiva (P50) seguida de uma onda maior negativa (N95). A neuropatia óptica glaucomatosa causa perda progressiva das células ganglionares da retina, detectável como anormalidades no exame, especialmente na onda N95. Por isso, o eletroretinograma de padrão reverso pode ser útil no diagnóstico e seguimento de pacientes glaucomatosos. Este artigo é uma revisão atualizada dos dados publicados a respeito da capacidade do eletroretinograma de padrão reverso em detectar alterações retinianas induzidas pelo glaucoma.

Alterações eletrofisiológicas na doença de Oguchi / Electrophysiological findings in Oguchi disease

Descrever as alterações eletrofuncionais em um caso raríssimo da Doença de Oguchi. Paciente do sexo feminino, italiana de 17 anos de idade se queixava de cegueira noturna. A resposta escotópica de bastonetes, do ERG era não registrável. A resposta escotópica ao estímulo branco forte demonstrava uma diminuição de amplitude da onda B. As respostas ao flicker de 30Hz e ao EOG eram dentro dos limites da normalidade. Era presente o fenômeno de Mizuo-Nakamura. Os exames eletrofuncionais são muito importantes no diagnóstico de certeza da doença de Oguchi. É nítida, no presente caso, a discordância entre EOG e ERG. Considerando a função dos bastonetes, as respostas normais do EOG contrastam com a ausência de respostas dos bastonetes em condições escotópicas no ERG. Mais estudos são necessários para entender o complexo mecanismo eletrofuncional dessa doença e melhor definir a origem dos componentes sensíveis à luz do EOG...

To describe the electrophysiological alterations in a very rare case of Oguchi's disease. A 17-year-old italian girl complaining of night blindness underwent complete ophthalmological exams, including electrophysiological tests. Rod responses were nondetectable in full-field electroretinogram (ERG). The photopic ERG funtions, including the 30 Hz flicker ERG response was normal, while the scotopic b-wave was diminished in amplitude. The electrooculography (EOG) ratios within the normal range were 208% in the right eye and 222% in the left eye. The Mizuo-Nakamura phenomenon was present. The electrophysiological tests are important tools in Oguchi's disease diagnosis. In the present case, it's clear the non correspondance between EOG and ERG. Considering the rod function, the normal EOG ratio contrast with non-detectable rod ERG responses. More studies are necessary to understand the compless electrofuntional mecanism of the disease helping to understand the origin of the light-sensitive component of the EOG...

Electroretinography in dogs using a fiber electrode prototype

We compared two electroretinography (ERG) electrodes in dogs using ERG standards of the International Society for Clinical Electrophysiology of Vision (ISCEV). Ten healthy Yorkshire terrier dogs (mean age, 2.80 ± 1.42 years; 6 females) weighing 5.20 ± 1.56 kg were evaluated using an ERG system for veterinary use. Dark- and light-adapted ERG responses were recorded using an ERG-Jet electrode and a fiber electrode prototype. The examinations were performed during 2 visits, 3 weeks apart. Both electrodes (ERG-Jet or fiber prototype) were used on each animal and the first eye to be recorded (OD × OS) was selected randomly. Three weeks later the examination was repeated on the same animal switching the type of electrode to be used that day and the first eye to be examined. The magnitude and waveform quality obtained with the two electrode types were similar for all ERG responses. ERG amplitudes and implicit times obtained from dogs using the fiber electrode prototype were comparable to those obtained with the ERG-Jet electrode for rod, maximal rod-cone summed, cone, and 30-Hz flicker responses. The fiber electrode prototype is a low-cost device, available as an alternative instrument for clinical veterinary ERG recording for retinal function assessment.

Electroretinography recordings using a light emitting diode active corneal electrode in healthy beagle dogs

Electroretinography (ERG) is a well-established diagnostic procedure for objectively evaluating retinal function. In this study, ERG in beagle dogs, which are a popular experimental animal, was performed to determine the normal range of ERG variables and assess differences between the left and right eyes. ERG findings including rod, combined rod-cone, single-flash cone, and 30-Hz flicker responses were recorded with an LED-electrode in 43 sedated beagle dogs. The subjects were divided into young ( or = 6 years old). Normal ERG ranges were obtained. Significant differences in b-wave amplitude along with b/a ratio of the combined rod-cone response were found between the young and adult animals as well as young and senile dogs. No significant differences were observed between the left and right eyes. ERG variables in beagle dogs differed by age due to age-related retinal changes. Thus, we propose that normal ERG ranges should be determined according to age in each clinic and laboratory using its own equipment because each institution usually has different systems or protocols for ERG testing.

Clinical Usefulness of Binocular Multifocal Electroretinography in Patients with Monocular Macular Disease

PURPOSE: To evaluate the clinical usefulness of binocular multifocal electroretinography (mfERG) by comparing results with conventional monocular mfERG in patients with monocular macular disease. METHODS: mfERG testing was conducted on 32 patients with monocular macular disease and 30 normal subjects. An initial mfERG was simultaneously recorded from both eyes with two recording electrodes under binocular stimulation. A second mfERG was subsequently recorded with conventional monocular stimulation. Amplitudes and implicit times of each ring response of the binocular and monocular recordings were compared. Ring ratios of the binocular and monocular recording were also compared. RESULTS: In the macular disease group, there were no statistical differences in amplitude or implicit time for each of the five concentric rings between the monocular and binocular recordings. However, with binocular simulation, the ring ratios (ring 1 / ring 4, ring 1 / ring 5) were significantly reduced in the affected eye. In the normal control group, there were no statistical differences in any parameters between the monocular and binocular recordings. CONCLUSIONS: Binocular mfERG could be a good alternative to the conventional monocular test. In addition, given that the test needs stable fixation of the affected eye during the binocular test, the reliability of the test results could be improved, especially for patients with monocular macular disease.

Multifocal visual electrophysiology in visual function evaluation / 法医学杂志

Multifocal visual electrophysiology, consisting of multifocal electroretinography (mfERG) and multifocal visual evoked potential (mfVEP), can objectively evaluate retina function and retina-cortical conduction pathway status by stimulating many local retinal regions and obtaining each local response simultaneously. Having many advantages such as short testing time and high sensitivity, it has been widely used in clinical ophthalmology, especially in the diagnosis of retinal disease and glaucoma. It is a new objective technique in clinical forensic medicine involving visual function evaluation of ocular trauma in particular. This article summarizes the way of stimulation, the position of electrodes, the way of analysis, the visual function evaluation of mfERG and mfVEP, and discussed the value of multifocal visual electrophysiology in forensic medicine.

Multifocal electroretinogram in normal emmetropic subjects: Correlation with optical coherence tomography.

Aim of the Study: To establish the normative database for multifocal electroretinogram (mfERG) parameters in a normal emmetropic population. To correlate the data so obtained with the central macular thickness obtained using the optical coherence tomography (OCT) scan. Materials and Methods: mfERG data were obtained from 222 eyes of 111 emmetropic subjects. The amplitude (nv/deg2) and implicit times (ms) of the first-order kernel mfERG responses (N1, P1, and N2 waves) were obtained and grouped into five rings (Ring 1: Central 2°, Ring 2: 2–5°, Ring 3: 5–10°, Ring 4: 10–15°, Ring 5: >15°). The central macular thickness (CMT) was obtained using the macular thickness scan protocol of the OCT. Results: The mfERG data obtained were used to create a normative database. The amplitudes of the mfERG waves were maximum in the fovea and progressively decreased with increasing eccentricity (P = 0.0001). The latencies of the P1 and N2 waves were longest in the central ring and progressively shortened with eccentricity (P = 0.0001). No statistically significant correlations were observed between central ring 1 parameters and the CMT. Conclusion: This study establishes normative database for mfERG parameters in an emmetropic population. No statistically significant correlation was noted between CMT and mfERG parameters.

Visual acuity and retinal function in patients with Bardet-Biedl syndrome

OBJECTIVE: Bardet-Biedl syndrome is a genetic, multisystem disorder that causes severe visual impairment. This condition is characterized by retinal dystrophy, obesity, digit anomalies, renal disease, and hypogonadism. The purpose of this study was to analyze visual acuity and full-field electroretinogram findings in patients with the Bardet-Biedl syndrome phenotype. METHODS: The visual acuity of a group of 23 patients (15 males) with ages ranging from 6-36 years (mean = 15.8±6.4; median = 14.7) was assessed. Retinal function was evaluated by full-field electroretinography, and dark-adapted thresholds were assessed. RESULTS: Visual acuity in the better-seeing eye was 20/40 or better in 5 patients (21.7 percent), 20/50-20/150 in 13 (56.5 percent) patients, 20/200-20/400 in 2 (8.7 percent) patients and worse than 20/400 in one (4.3 percent) patient. The mean acuity in the better-seeing eye was 0.7±0.6 logMAR (20/100, Snellen equivalent). Scotopic rod and maximal responses were nondetectable in 21 (91.3 percent) patients, and cone responses were non-detectable in 15 (65.2 percent) patients. Elevated darkadapted visual thresholds were observed in all 19 patients who were able to be assessed, with 10 (52.6 percent) patients having thresholds greater than 30 dB. CONCLUSIONS: In a relatively young cohort of patients with Bardet-Biedl syndrome, only 21 percent had 20/40 or better vision. ERG scotopic responses were absent in the majority of cases, with cone responses being observed in less than half of cases. These findings showed the early deleterious effects in retinal function and visual acuity caused by this condition.

Principal components’ analysis of multifocal electroretinogram in retinitis pigmentosa.

Aims: To determine waveforms of multifocal electroretinogram (mfERG) in patients with retinitis pigmentosa (RP) contributing significantly to the overall retinal response by using principal components’ analysis. Settings and Design: Prospective, non-randomized, single-visit, observational, case-control study from a single tertiary ophthalmic center. Materials and Methods: Patients with various forms of RP underwent mfERG testing for a period of one year. The first-order kernel responses of RP cases were compared with concurrently recruited healthy controls. Statistical Analysis Used: Parametric data was analyzed using the unpaired t test for differences between the implicit time and amplitudes of cases and controls. Principal components’ analysis was done for each implicit time and amplitude in cases with RP using the Varimax rotation method. Results: From March 2006 to March 2007, 24 cases with typical RP (56%, 47 eyes) were included in the final analysis. Their mean age was 33.7 years (19-69 ± 15.5 years). Comparison of latencies and amplitudes among RP cases with log MAR acuity ≤ 0.18 and those > 0.18, revealed significant difference in the implicit time (P1) in Ring 2 only (P=0.028). Two components (predominently from Ring 1 and 2) each contributing 66.8% and 88.8% of the total variance in the data for latencies and amplitudes respectively, were seen. Conclusions: The first two rings of the mfERG contributed to the variance of waveforms in RP, irrespective of the visual acuity and poor visual field results.

Pattern-reversal electroretinograms for the diagnosis and management of disorders of the anterior visual pathway / Eletroretinograma de padrão reverso no diagnóstico e acompanhamento das afecções da via óptica anterior

The pattern electroretinogram is an electrophysiological test that assesses the function of inner retinal layers, particularly the ganglion cells layer of retina, using a reversing checkerboard or grating pattern that produces no change in average luminance over time. The normal pattern electroretinogram is composed of a proeminent positive component (P50) and a large later negative component (N95). Since structural damage that compromises the retinal ganglion cell layer can lead to pattern electroretinogram changes, particularly in the N95 amplitude, the test can be useful in the treatment of a number of anterior visual pathway diseases. In this article, we review the methods for recording pattern electroretinogram and its usefulness in the diagnosis and management of diseases including inflammatory, hereditary, ischemic and compressive lesions of the anterior visual pathway.

O eletroretinograma de padrão reverso é um teste eletrofisiológico que avalia a função das camadas internas da retina, especialmente a camada de células ganglionares, através de um estímulo em xadrez ou em barras que não apresenta variação na luminância do estímulo. É composto de um componente positivo (P50) e um componente negativo (N95) tardio. Uma vez que lesões estruturais às células ganglionares da reitna podem levar a alterações no eletroretinograma de padrão reverso, especialmente na amplitude da onda N95, o teste pode ser útil no tratamento de várias doenças da via óptica anterior. Neste artigo revisamos os métodos de obtenção do eletroretinograma de padrão reverso e a sua utilidade no diagnóstico e acompanhamento de doenças incluindo lesões inflamatórias, hereditárias, isquemicas e compressivas na via óptica anterior.

Multifocal Electroretinogram Findings after Intravitreal Bevacizumab Injection in Choroidal Neovascularization of Age-Related Macular Degeneration

PURPOSE: To evaluate the changes in multifocal electroretinogram (mfERG) and optical coherence tomography (OCT) after intravitreal bevacizumab injection in the treatment of age-related macular degeneration (AMD). METHODS: Twenty-one eyes with choroidal neovascularization secondary to AMD were studied before and after intravitreal bevacizumab injection for best corrected visual acuity (BCVA), OCT, and mfERG. RESULTS: The BCVA improved, while central macular thickness and total macular volume in OCT decreased after intravitreal bevacizumab injection (p = 0.03, 0.01, and 0.01, respectively). In mfERG, the amplitude of P1, and implicit time of P1 and N1 indicated a statistically significant improvement of retinal response after intravitreal bevacizumab injection. CONCLUSIONS: There is a potential role for mfERG in evaluating the effect on retinal function of intravitreal bevacizumab injection.

Comparison of full-field electroretinogram in diabetic and non diabetic dogs with cataracts / Estudo comparativo do eletrorretinograma de campo total em cães diabéticos e não diabéticos com catarata

Being the commonest ocular disorder, dense cataracts disable fundoscopic examination and the diagnosis of retinal disorders, which dogs may be predisposed. The aim of this study was to compare the electroretinographic responses recorded according to the International Society for Clinical Electrophysiology of Vision human protocol to evaluate retinal function of diabetic and non diabetic dogs, both presenting mature or hypermature cataracts. Full-field electroretinogram was recorded from 66 dogs, with ages varying from 6 to 15 years old allocated into two groups: (1) CG, non diabetic cataractous dogs, and (2) DG, diabetic cataractous dogs. Mean peak-to-peak amplitude (microvolts) and b-wave implicit time (milliseconds) were determined for each of the five standard full-field ERG responses (rod response, maximal response, oscillatory potentials, single-flash cone response and 30 Hz flicker). Comparing CG to DG, ERGs recorded from diabetic dogs presented lower amplitude and prolonged b-wave implicit time in all ERG responses. Prolonged b-wave implicit time was statistically significant (p< 0.05) at 30 Hz flicker (24.0 ms versus 22.4 ms). These data suggests full-field ERG is capable to record sensible alterations, such as flicker's implicit time, being useful to investigate retinal dysfunction in diabetic dogs.

Catarata madura e hipermadura, alteração frequentemente observada em cães, impossibilita a visibilização do fundo do olho e provável diagnóstico de degenerações retinianas. Objetivou-se comparar as respostas retiniana de cães diabéticos e não diabéticos, ambos portadores de catarata madura ou hipermadura, com auxílio do eletrorretinograma de campo total, utilizando o protocolo da International Society for Clinical Electrophysiology of Vision. Sessenta e seis cães, com idades variando entre 6 a 15 anos de idade foram divididos em dois grupos: (1) CG, cães não diabéticos com catarata madura ou hipermadura e (2) DG, cães diabéticos com catarata madura ou hipermadura. Mensurou-se amplitude pico a pico (microvolts) e tempo de culminação da onda-b (milisegundos) para as cinco respostas do ERG (resposta de bastonetes, máxima resposta, potencial oscilatório, resposta de cones e flicker a 30Hz). Avaliando-se as respostas obtidas com o exame, o grupo de cães diabéticos apresentou menor amplitude e maior tempo de culminação da onda-b em todas as respostas. O aumento do tempo de culminação da onda-b em DG foi estatisticamente significante (p<0.05) no flicker a 30 Hz (24.0ms versus 22.4ms). ERG de campo total é capaz de registrar alterações em respostas sensíveis como o tempo de culminação da onda-b do flicker, podendo ser útil para investigar retinopatias em cães diabéticos.

Estudo normativo do eletrorretinograma por padrões (PERG) em adultos / Pattern-reversal electroretinogram (PERG): a normative study in adults

Objetivo: Determinar valores para o eletrorretinograma por padrões (PERG) em voluntários adultos saudáveis seguindo o protocolo padrão recomendado pela International Society for Clinical Electrophysiology of Vision-ISCEV. Métodos: Os participantes foram 30 voluntários saudáveis (15 homens), com idade variando de 18 a 61 anos (média= 30,8 ± 8,7 anos, mediana= 29,6 anos). Os critérios de inclusão foram: acuidade visual 0,0 logMAR (20/20 Snellen) em cada olho separadamente, ausência de queixas visuais, ausência de opacidades de meio, ausência de história pregressa de doenças oculares ou neurológicas, história familiar negativa para doenças oculares e assinatura de termo de consentimento livre e esclarecido para participação em pesquisa. O PERG foi registrado em sala escura a 1 metro de distância de um monitor de alta resolução. Os estímulos foram padrões monocromáticos em forma de tabuleiro de xadrez subtendendo 60, 15 e 7,5 minutos de arco revertendo a 1,9 Hz. As respostas foram obtidas com variante de eletrodo descartável de filamento desenvolvido pela UNIFESP. Latência (milissegundos) para os componentes N35, P50 e N95 bem como a amplitude (microvolts) pico a pico para o N35-P50 e P50-N95 foram determinadas. Para estudo normativo apenas um olho escolhido ao acaso foi incluído. Os limites normais foram calculados pelo percentil 97,5 por cento para latência e 2,5 por cento para amplitude em cada tamanho de estímulo. Resultados: Valores normativos para latência de N35, P50 e N95 para os estímulos de 60', 15' e 7,5' foram respectivamente: N35 - 40,1; 39,9 e 41,3 ms; P50 - 60,5; 64,4 e 65,6 ms; N95 - 103,4; 104,6 e 104,6 ms. Para amplitude os valores normativos para os estímulos 60', 15' e 7,5' foram respectivamente: N35-P50 - 1,7; 1,6 e 0,9 µV; P50-N95 - 3,8; 2,8 e 1,5 µV. Não houve diferenças entre os sexos para os três estímulos empregados tanto para latência como para amplitude. Não encontramos correlação entre os parâmetros estudados...

Purpose: To determine normative values for pattern-reversal electroretinogram (PERG) in healthy adult volunteers according to the standard protocol recommended by the International Society for Clinical Electrophysiology of Vision-ISCEV. Methods: Participants were 30 healthy volunteers (15 males) with ages from 18 to 61 years (mean= 30.8 ± 8.7 yrs.; median= 29.5 yrs). Inclusion criteria were: visual acuity of 0.0 logMAR (20/20 Snellen) in each eye, absence of visual complaints, absence of media opacities, negative history for ocular or neurological diseases, negative family history for ocular and informed consent. PERG was recorded from each eye in a darkened room at 1 m from a high resolution display monitor. Stimuli were monochromatic checkerboards subtending 60, 15 e 7.5 minutes of visual angle reversing at 1.9 Hz. Responses were obtained from modified disposable fiber electrodes developed at UNIFESP. Latency (ms) for N35, P50 and N95 components as well as peak-to-peak amplitudes (µV) for N35-P50 and P50-N95 were determined. For normative values only one randomly chosen eye was included. Normal limits were calculated as 97.5 percent percentiles for latency and 2.5 percent percentile for amplitudes for each stimulus size. Results: Normal limits for N35, P50 and N95 latencies for 60', 15' and 7.5' stimuli were respectively: N35 - 40.1; 39.9 and 41.3 ms; P50 - 60.5; 64.4 and 65.6 ms and N95 - 103.4; 104.6 and 104.6 ms. For amplitude the normative values for N35-P50 and P50-N95 for 60', 15' and 7.5' were respectively: N35-P50 - 1.7; 1.6 and 0.9 µV; P50-N95 - 3.8; 2.8 and 1.5 µV. No gender differences were found either for latency or for amplitude in the three stimulus sizes. There was no correlation between PERG latency and amplitude with age, except for P50 amplitude for stimulus 15'(r=0.39; P=0.035). Conclusions: Normative values were determined for PERG parameters of amplitude and latency for three stimulus sizes. These parameters are...