Effects produced by different types of laser in cornea of Guinea pigs: Identification of a laser capable of producing superficial lesions without leaving scars.

PURPOSE: Climatic droplets keratopathy (CDK) is closely associated with superficial corneal erosions and lack of protective mechanisms against the harmful effects of ultraviolet radiation (UVR) during a prolonged period of time. One of the difficulties in studying the pathogenic mechanisms involved in this human disease is the lack of an experimental animal model. In this paper, a study is conducted on the effects of 4 types of lasers at various powers and time conditions on the normal guinea pig corneas in order to select only one laser condition that reversibly injures the epithelium and superficial stroma, without leaving scarring. METHODS: Damage was induced in the cornea of Guinea pigs using different powers and exposure times of 4 types of laser: argon, CO2, diode and Nd-Yag, and any injuries were evaluated by biomicroscopy (BM) and optical microscopy. Corneas from other normal animals were exposed to argon laser (350 mW, 0.3s, 50 µm of diameter), and the induced alterations were studied at different times using BM, optical coherence tomography (OCT) and transmission electron microscopy (TEM). RESULTS: Only argon laser at 350 mW, 0.3s, 50 µm of diameter produced epithelium and superficial stroma lesions. Some leukomas were observed by BM, and they disappeared by day 15. Corneal thickness measured by OCT decreased in the eyes treated with argon laser during the first week. Using TEM, different ultra structural alterations in corneal epithelium and stroma were observed during the early days, which disappeared by day 15. CONCLUSIONS: It was possible to develop reproducible corneal epithelium and anterior stroma injuries using Argon laser at 350 mW, 0.3s, 50 µm of diameter. In vivo and in vitro studies showed that injured corneas with these laser conditions did not leave irreversible microscopic or ultra structural alterations. This protocol of corneal erosion combined with exposure to UVR and partial deficiency of ascorbate in the diets of the animals for an extended period of time has been used in order to try to develop an experimental model of CDK.

On the Cornea of Healthy Merino Sheep: A Detailed Ex Vivo Confocal, Histological and Ultrastructural Study.

Our study performed qualitative and quantitative studies on the corneal ultrastructure of healthy female Merino sheep of ages 4 months and 6 years old from the Argentinean Pampa. The corneas were evaluated using ex vivo laser-scanning confocal microscopy, light microscopy and transmission electron microscopy. Those studies allowed us to obtain detailed images of the corneal layers as well as quantitative data of the cellular and sub-basal nerve densities in the cornea from sheep of different ages. The density of the corneal cells was significantly different in the anterior versus the posterior epithelium and stroma. Moreover, the density of the epithelial, stromal cells and endothelial cells, as well as the sub-basal nerve density were significantly lower in adult than in young animals. Our work provided a wide-ranging description of the corneal ultrastructure of healthy female Merino sheep, which adds to the current knowledge about the ophthalmological aspects of this species and undoubtedly benefits veterinarians.

Clinical signs and symptoms are not enough for the correct diagnosis of allergic conjunctivitis.

BACKGROUND: Allergic Conjunctivitis (AC) has a high incidence in the general population and sometimes it is difficult to make a correct diagnosis, distinguish among the different subtypes of AC, and therefore, to indicate the suitable therapy. OBJECTIVE: To determine the best way to carry out an appropriate diagnosis of AC. METHODS: Thirty-one patients with clinical manifestations of AC and eleven controls were studied by measuring allergic and immunologic parameters. Only those patients confirmed as having AC were treated with ketotifen fumarate and further evaluated. RESULTS: According to allergic and immunological parameters, patients were divided into two groups. Group I patients had positive prick test toward at least one allergen, 60% exhibited high levels of tear-IgE, and only 36% conjunctival eosinophils. By contrast, patients from Group II had negative prick tests and laboratory findings similar to the control group. In group I there was a good correlation between levels of tear-IgE and eosinophils (r = 0.55; p = 0.009); key symptoms and signs and prick test (r = 0.52; p = 0.015), and prick test and eosinophils (r = 0.50 p = 0.022). The cardinal signs and symptoms scores dropped significantly in Group I as a consequence of the treatment (p < 0.0001). CONCLUSION: In order to have a reliable AC diagnosis, allergen-skin prick test, IgE in tears, and conjunctival eosinophils must be studied. Serum IgE is less important.

[Retinal detachment caused by small tears in the equatorial region of the retina]. / Décollements rétiniens par petits trous de la région équatoriale.

46 Phakic rhegmatogenous retinal detachments due solely to round atrophic holes in the equatorial region were observed in 42 patients. The clinical characteristics and the prognosis of the retinal detachments differ from those of retinal detachments associated with horse-show retinal tears. The 46 phakic retinal detachments due solely to round atrophic holes in the equatorial region account for 5.8% of all rhegmatogenous retinal detachments operated during the same period of time, 81% of the patients were under 40 years of age, 93.5% of the eyes were myopic. The round atrophic holes were located within foci of equatorial lattice degeneration in 97.8% of the eyes. The number of holes per eye varied from 1 to 16 with a mean number of 4.54. The location of the holes showed a significant prevalence for the lower temporal quadrant (83.3% of the eyes) and then the upper temporal quadrant (47.8% of the eyes). The retinal detachments had a slow progression and demarcation lines were present in 56.5% of the eyes. In spite of the long standing duration none of the detachments were associated with clinical evidence of proliferative vitreo retinopathy. Surgical prognosis was excellent. Retinal reattachment was achieved in all cases. Post operative visual acuity of 20/40 or better was achieved in 60% of the eyes. It is assumed that the absence of proliferative vitreo retinopathy in those retinal detachments is related to the absence of significant vitreous degeneration and posterior vitreous detachment.

[Slit-lamp laser photocoagulation with a quadraspheric contact lens for the treatment of retinopathy of prematurity]. / Photocoagulation au laser avec lampe à fente et verre de contact quadrasphérique dans la rétinopathie des prématurés.

PURPOSE: To present our experience of slit-lamp laser photocoagulation with a pediatric quadraspheric contact lens for the treatment of retinopathy of prematurity (ROP). MATERIAL AND METHODS: 8 eyes of 4 premature babies with threshold ROP were consecutively treated under general anesthesia by means of blue-green argon laser photocoagulation delivered through a table mounted slit-lamp and a wide field contact lens specially designed for infants. Three of the treated eyes had a zone I disease, 2 a posterior zone II disease and 3 a zone II disease. Mean follow-up was 13 months. RESULTS: Early complete regression of the neovascular proliferations and plus disease was observed in all the treated eyes (100%) without apparent sequela. In only one eye that had zone I disease a mild and small peripheral vitreous hemorrhage was observed. Neither cataract nor posterior synechia was observed. A discrete and transient badly hypothermia occurred only in one case. COMMENTS AND CONCLUSIONS: This study shows the efficacy and precision of slit-lamp argon laser photocoagulation through a quadraspheric contact lens in ROP, with a very low rate of complications, and with a magnificent and comfortable visualization of all the structures to be treated. Each retinal burn was easily and very precisely placed from the ridge to the ora serrata in 360 with only a slight to moderate tilting of the wide field lens and without the need of scleral depression.

Participación de componentes inmunológicos en la etiopatogenia de la queratopatía climática esferoidea / Involvement of immune components in the etiopathogenia of climatic droplet keratopathy

Objetivo. Investigar si componentes de la inmunidad innata están involucrados en la iniciación/perpetuación de las anormalidades estructurales observadas en la capa de Bowman y el estroma superficial de la córnea de pacientes con queratopatía climática esferoidea (QCE). Materiales y métodos. En el estudio participaron 8 pacientes con QCE y 12 individuos sanos del Departamento El Cuy, Provincia de Río Negro, y 10 individuos sanos de la ciudad de Córdoba. Todos ellos, luego de firmar el consentimiento informado, recibieron un examen oftalmológico completo y se recolectaron muestras de lágrima para estudiar las concentraciones de diferentes citocinas, niveles y formas de metaloproteinasas de matriz (MMPs), y el inhibidor natural de MMPs (TIMP-1). Se realizó microscopía confocal in vivo (MCF) en algunos pacientes y controles. Biopsias de córneas provenientes de pacientes que fueron tratados con queratoplastia penetrante también fueron estudiadas mediante inmunohistoquímica (IHQ). Resultados. Los resultados de MCF indicaron claramente una progresión en la cantidad de depósitos a nivel subepitelial, a medida que la enfermedad avanza. El daño progresivo de las fibras nerviosas sub basales y estromales en los estadios 2 y 3 se correlaciona con pérdida de la sensibilidad corneal. Además de estas alteraciones, observamos que el número de células dendríticas (CD) en el limbo corneal aumentó significativamente a medida que la QCE progresa. En lágrimas de pacientes con QCE se detectaron concentraciones significativamente superiores de citocinas proinflamatorias (IL1ß e IL-8) que en individuos controles (p<0,005). No se halló IL-2, IL-17, IL-4, IL-13 ni IL-10 en pacientes y ni controles. Las actividades de gelatinasas (MMP-9 y -2) fueron significativamente mayores en QCE que en los controles (p<0,001), mientras que los niveles de TIMP-1 fueron significativamente menores en los pacientes (p<0,05). La concentración de MMP-8 fue mayor en controles pero los niveles de esta colagenasa-2 fueron 30 veces superiores, tanto en QCE como controles, con respecto a los valores de los individuos de un centro urbano. Mediante IHC observamos reactividad para MMP-9 en la mayoría de las células epiteliales, solamente en córneas con QCE. Conclusión. Demostramos un rol protagónico del eje citocinas proinflamatorias - gela-tinasas en el desarrollo de la QCE. Los altos niveles de IL-1ß e IL-8 en lágrimas de pacientes facilitan la producción de MMP-8 y gelatinasas, y los efectos de las mismas se exacerban, ya que los pacientes tienen bajos niveles de sus inhibidores naturales (TIMP-1). La MMP-9, además de degradar componentes de la matriz extracelular, cataliza la activación postranscripcional de IL-1ß, potenciando el proceso inflamatorio. Estos resultados son los primeros en explicar mecanismos inmunológicos involucrados en la etiopatogénesis de la QCE y aportan nuevas alternativas para el desarrollo de terapias preventivas utilizando inhibidores de IL-1ß y/o gelatinasas(AU)

Objective. To investigate whether components of innate immunity are involved in the initiation / perpetuation of the structural abnormalities observed in Bowman's layer and superficial stroma of the córnea of patients with Climatic droplet keratopathy (CDK). Materials and Methods. The study included 8 CDK patients and 12 healthy individuals from Department El Cuy, Province of Río Negro, and 10 healthy subjects from the city of Córdoba. All of them, after signing informed consent, received a thorough eye exam and tear samples were collected to study the concentrations of different cytokines, and levels and forms of matrix metalloproteinases (MMPs) and their natural inhibitor (TIMP-1). In vivo confocal microscopy (CFM) was performed in some patients and controls. Corneal biopsies from CDK patients treated with penetrating keratoplasty were also studied by immunohistochemistry (IHC). Results. CFM results clearly indicated a progression in the amount of deposits at corneal sub epithelial level as the disease progresses. The progressive damage in the nerve plexus in stages 2 and 3 correlated with a loss of corneal sensitivity. In addition to these alterations, we observed that the number of dendritic cells (DC) in the limbus increased significantly as the disease progresses.In tears of patients with CDK we detected significantly higher concentrations of pro-inflammatory cytokines (IL-1ß and IL-8) than in control subjects (p < 0.005). We found no IL-2, IL-17, IL-4, IL-13 and IL-10 in patients and controls. The activities of gelatinases (MMP-9 and -2) were significantly higher in CDK than in controls (p < 0.001), while TIMP-1 levels were significantly lower in patients (p < 0.05). The concentration of MMP-8 was higher in controls, but levels of this collagenase-2 were 30 times higher, both in CDK and controls, with respect to MMP-8 values of individuals inhabiting an urban area. By IHC we observed reactivity for MMP-9 in most epithelial cells only in CDK corneas. Conclussion. We demonstrated a key role of the axis pro-inflammatory cytokines ­ gelatinases in the development of CDK. High levels of IL-1ß and IL-8 in tears of patients facilitate the production of MMP-8 and gelatinases, and the effects of these molecules are exacerbated because patients have low levels of their natural inhibitors (TIMP-1). Since MMP-9 besides degrading extracellular matrix components, catalyzes the post translational activation of IL-1ß, the inflammatory process is fuelled. These results are the first to explain immunological mechanisms involved in the pathogenesis of the QCE and provide new alternatives for the development of preventive therapies using inhibitors of IL-1ß and / or gelatinases.(AU)

Hacia un mejor diagnóstico de conjuntivitis alérgica / Towards the best diagnosis of allergic conjunctivitis

Antecedentes: la conjuntivitis alérgica (CA) tiene una elevada incidencia en la población general y el diagnóstico es realizado por oftalmólogos a través de síntomas y signos oculares característicos. Objetivo: determinar la mejor manera de realizar un diagnóstico preciso de CA. Materiales y métodos: se estudiaron veintidós pacientes con síntomas de CA en el nivel clínico, alergológico e inmunológico antes y después del tratamiento con fumarato de ketoifeno 0,05 por ciento tópico. Resultados: el 83 por ciento de la población estudiada tenía antecedentes familiares de alergia y el 100 por ciento tuvo pruebas cutáneas positivas hacia diferentes alergenos. El 30 por ciento presentó niveles de IgA sérica elevados y el 60 por ciento en lágrimas. Todos los pacientes tuvieron niveles normales de IgA secretoria y lisozima A y valores no detectables de VCAM-1s. El estudio de las moléculas CD29 y HLA-DR sobre células epiteliales conjuntivales antes del tratamiento mostró un marcado incremento en el porcentaje de las mismas con respecto a valores normales. Encontramos correlación entre valores de IgE en lágrimas y eosinófilos (r=0,56; p=0,007); índice de síntomas y signos cardinales e índice de pruebas cutáneas (r=0,50; p=0,032); índice de pruebas cutáneas y eosinófilos conjuntivales (r=0,48; p=0,024); e índice de síntomas y signos cardinales y niveles de IgE sérica (r=0,45; p=0,018). El porcentaje de células CD29+ disminuyó significativamente como consecuencia del tratamiento (p=0,03) mientras que el porcentaje de células HLA-DR+ solo disminuyó en el 41 por ciento de pacientes. Conclusiones: en el diagnóstico de la CA son parámetros críticos los signos y síntomas cardinales, pruebas cutáneas, eosinófilos conjuntivales e IgE en lágrimas