Efecto de la lente fáquica ACR-128 sobre la tensión ocular y el endotelio corneal en las altas miopías / Effect of the ACR-128 phakic lens on ocular tension and the corneal endothelium in high myopia

RESUMEN Objetivo: Describir los efectos sobre la tensión ocular y el endotelio corneal con el implante de la lente fáquica ACR-128 para la corrección de la alta miopía. Métodos: Se realizó un estudio descriptivo, observacional, longitudinal y prospectivo en 60 ojos de 32 pacientes con miopía corregida con lente fáquica ACR-128. Se determinaron las complicaciones trans y posoperatorias, la presión intraocular, la densidad de las células endoteliales, el coeficiente de variabilidad y la hexagonalidad, así como la posición de la lente. El análisis estadístico se realizó con la Prueba T para datos pareados, con una significación del 95 por ciento. Resultados: La edad media fue de 27,41 ± 5,91 años y el 68,75 por ciento correspondió al sexo femenino. El equivalente esférico preoperatorio promedio fue de -11,54 ± 3,20 dioptrías. Resultó sin complicaciones transoperatorias el 100 por ciento; las posoperatorias inmediatas fueron de 93,33 por ciento y las mediatas y tardías del 95,00 por ciento. No hubo diferencias significativas entre el pre y el posoperatorio en la tensión ocular (p=0,2570); la densidad endotelial fue p= 0,0928; el coeficiente de variación p= 0,889 y la hexagonalidad (p= 0,0957). Conclusiones: El implante de la lente fáquica ACR-128 para la corrección de las altas miopías es un procedimiento seguro, al ofrecer escasas complicaciones y mínimos efectos en la tensión ocular y en el endotelio corneal(AU)

ABSTRACT Objective: Describe the effects of ACR-128 phakic lens implantation for high myopia correction on ocular tension and the corneal endothelium. Methods: An observational descriptive longitudinal prospective study was conducted of 60 eyes of 32 patients with myopia corrected with the ACR-128 phakic lens. Determination was made of intra- and postoperative complications, intraocular pressure, endothelial cell density, variability and hexagonality quotient, and lens position. Statistical analysis was based on the paired T-test with a significance level of 95 percent. Results: Mean age was 27.41 ± 5.91 years and 68.75 percent of the patients were female. Mean preoperative spherical equivalent was -11.54 ± 3.20 diopters. Complications were none in the intraoperative period, 93.33 percent in the immediate postoperative period and 95.00 percent mid- or long-term. No significant differences were found between the pre- and postoperative periods concerning ocular tension (p= 0.2570). Endothelial cell density was p= 0.0928, the variability quotient p= 0.889 and hexagonality p= 0.0957. Conclusions: ACR-128 phakic lens implantation for correction of high myopia is a safe procedure causing few complications and minimal effects on ocular tension and the corneal endothelium(AU)

Síndrome de Chandler / Chandler's syndrome

El síndrome de Chandler es una de las variaciones clínicas del síndrome iridocorneoendotelial, donde el denominador común es una alteración del endotelio corneal cuyo diagnóstico es, en ocasiones, muy difícil de realizar por la complejidad y la variabilidad de sus signos y síntomas. Se presenta una paciente de 67 años con disminución importante de la visión del ojo izquierdo. A la exploración existía un edema corneal severo, una midriasis pupilar, una corectopia leve hacia el sector temporal con tracción iridiana hacia el ángulo y sinequias anteriores angulares en el lado de la corectopia. La realización de un recuento endotelial demostró alteraciones cuali y cuantitativas del endotelio en el ojo izquierdo. Se concluyó que la microscopia especular es fundamental para el diagnóstico y la evaluación en casos sospechosos de síndrome de Chandler(AU)

Chandler's syndrome is a clinical variant of the iridocorneal endothelial syndrome in which the common aspect is the altered corneal endothelium that is sometimes very difficult to be diagnosed on account of the complexity and variability of signs and symptoms. This article was aimed at showing the effectiveness of specular microscopy for diagnosis. Here is a 67 years-old female patient who had significant reduction of vision in her left eye. On examination, there were observed severe corneal edema, pupillary mydriasis, mild corectopia towards the temporal sector with angled iridal traction and anterior angle synechias on the corectopia side. The endothelial counting revealed qualitative and quantitative alterations in the left eye. It was concluded that the specular microscopy is the key to diagnosis and assessment of suspected Chandler's syndrome cases(AU)

Absence of phenotype-genotype correlation of patients expressing mutations in the SLC4A11 gene.

PURPOSE: The purposes of this study were to describe the clinical characteristics of corneal patients with mutations in the SLC4A11 gene and to determine if these characteristics could be correlated with specific genetic mutations. METHODS: A retrospective case series review was conducted. Baseline demographic data, including gender, age at diagnosis of congenital hereditary endothelial dystrophy, family history, and pedigree information, were obtained. Information from clinical examination, including intraocular pressure, ultrasonic pachymetry, best spectacle-corrected visual acuity, axial length, and slit-lamp biomicroscopic evaluation, including corneal diameter and fundus examination, were also documented from the notes. History of corneal surgery was also recorded. Hearing loss was assessed by audiometry. Genetic analysis was performed by polymerase chain reaction amplification and sequencing. RESULTS: Seven patients were identified. Four of the seven had associated hearing loss; all of the patients had undergone or were awaiting penetrating keratoplasty to one or both eyes. No correlation could be reached between the ocular phenotype and the gene mutation in this small sample. Individuals with the same mutation had different degrees of hearing loss within their respective families. CONCLUSIONS: Corneal endothelial cells are more vulnerable to defects in the functional activity of SLC4A11 than cells of the striae vascularis of the inner ear. Both congenital hereditary endothelial dystrophy 2 and Harboyan syndrome have similar ocular phenotypes, ie, diffuse bilateral corneal edema present at birth or within the neonatal period; hence, audiometry must be performed to differentiate the two conditions.

Immunohistochemical characterization of cytokeratins in the abnormal corneal endothelium of posterior polymorphous corneal dystrophy patients.

Posterior polymorphous corneal dystrophy (PPCD) is a hereditary bilateral disorder affecting Descemet's membrane and the endothelium. The aim of the present study was to determine the spectrum of cytokeratin (CK) expression in cells on the posterior surface of the cornea in PPCD patients. Ten corneal buttons and one specimen of the trabecular meshwork (TM) from PPCD patients who underwent graft or glaucoma surgery were used, as well as six corneal buttons and two TM specimens obtained from healthy donors as controls. Cryosections were fixed and indirect immunofluorescent staining was performed using antibodies directed against a wide spectrum of cytokeratins (CKs). The number of positive cells and the intensity of the staining were assessed using fluorescent microscopy. All 10 PPCD corneal specimens had areas of endothelium displaying typical endothelial morphology as well as areas consisting of layers two to six cells thick with both flat endothelial-like cells and polygonal cells with round nuclei and a large cytoplasm. Both of these morphologically distinct cell types showed strong immunostaining for CK7, CK19, CK8 and CK18, while weaker positive signals were observed for CK1, CK3/12, CK4, CK5/6, CK10, CK10/13, CK14, CK16 and CK17. PPCD endothelium was completely negative for CK2e, CK9, CK15, and CK20. Focal positivity was detected in PPCD TM for CK4, CK7 and CK19. CK8 and CK18 were the only CKs expressed in control endothelium. PPCD and control epithelium displayed similar staining patterns. The distinct positivity for CK3/12, CK4, CK5/6, CK10/13, CK14, CK16 and CK17 was observed in aberrant PPCD endothelium for the first time. We demonstrate that the abnormal endothelium of PPCD patients expresses a mixture of CKs, with CK7 and CK19 predominating. In terms of CK composition, the aberrant PPCD endothelium shares features of both simple and squamous stratified epithelium with a proliferative capacity. The wide spectrum of CK expression is most probably not indicative of the transformation of endothelial cells to a distinct epithelial phenotype, but more likely reflects the modified differentiation of metaplastic epithelium.

Perinatal ablation of the mouse lens causes multiple anterior chamber defects.

PURPOSE: The purpose of this study was to reassess the role of the lens as an "embryonic organizer" of ocular tissues. METHODS: We ablated the lens in mice by lens-specific expression of an attenuated version of diphtheria toxin A subunit(Tox176) driven by a modified crystallin promoter. Alterations in the differentiation programs of ocular tissues were examined by hematoxylin and eosin staining, in situ hybridization, and immunohistochemistry. RESULTS: Transgenic mice in the family OVE1757 exhibited severe microphakia. Apoptotic lens fibers were seen by embryonic day 15 (E15) and the lenses were completely ablated by post natal day 8. Multiple defects were seen in the anterior chamber. Corneal endothelial cells did not differentiate properly. The mesenchymal cells that would normally give rise to the endothelial layer were found to express N-cadherin, but they failed to form tight junctions and undergo a mesenchymal-to-epithelial transition. Although early specification of the presumptive ciliary body and iris was detected, subsequent differentiation of the iris was blocked. No dramatic changes were seen in the development of the retina. CONCLUSIONS: These results support the hypothesis that an intact lens is essential for proper differentiation of both the corneal endothelium and the iris and that the lens "organizes" the development of tissues in the anterior chamber.

VSX1 (RINX) mutation with craniofacial anomalies, empty sella, corneal endothelial changes, and abnormal retinal and auditory bipolar cells.

PURPOSE: To present a previously unreported African American family with 1 variation and 1 mutation of the homeobox transcription factor gene, VSX1 (RINX), and to describe the clinical features of family members. DESIGN: Family genotype and clinical studies. PARTICIPANTS: A 3-generation family with 7 available family members. METHODS: Blood was drawn from all available family members, and the VSX1 (RINX) gene was sequenced. Craniofacial abnormalities, central nervous system defects, anterior segment features, and retinal and auditory function were assessed. MAIN OUTCOME MEASURES: Main outcome measures included identification and molecular characterization of 1 variation and 1 mutation in VSX1 (RINX) of 4 affected family members (3 adults and 1 child). Craniofacial features were documented. Central neuroimaging was performed. Ophthalmologic findings were described. Retinal and auditory functions were quantified. RESULTS: Two changes in VSX1 (RINX) were identified: a variation (R131S) not in a critical region and in few controls, and a mutation (A256S) in the critical CVC-domain and not in any controls. Both were present on 1 chromosome at 20p11.2 and were segregated with the 4 affected patients. Clinical features demonstrated extremely variable expressivity. Craniofacial features, including wide interpupillary distance and unusual pinnae, occurred in the 4 affected patients. Neuroimaging demonstrated that the propositus had an empty sella turcica, a posterior fossa cyst, an anterior encephalocele, hypertelorism, and severe hydrocephalus; her mother had a partially empty sella turcica, a small pituitary gland without any subarachnoid extension of fluid, and hypertelorism; and her older sister had hypertelorism but otherwise normal neuroimaging results. Anterior segment anomalies of the corneal endothelium were a constant finding in all affected family members. Electrophysiologic examination provided evidence for abnormal cone bipolar cells (visual evoked response and electroretinogram) in the adult affected patients and for abnormal auditory bipolar cells (audiogram and audio-evoked brainstem response) in the propositus. CONCLUSIONS: The new mutation in the VSX1 (RINX) gene described in this report results in abnormal craniofacial features, absence of the roof of the sella turcica, and anomalous development of the corneal endothelium. This mutation also impacts on the maintenance of cone bipolar cells of the visual system and of bipolar cells of the auditory system.

Cornea with Peters' anomaly: perturbed differentiation of corneal cells and abnormal extracellular matrix in the corneal stroma.

PURPOSE: We examined histopathologically the anterior ocular segment including the cornea and lens of an eye which had been enucleated in a patient with Peters' anomaly because of untreatable corneal perforation. Special effort was made to differentiate the corneal stromal and endothelial cells, and the stromal extracellular matrix. METHODS: Light microscopy, with hematoxylin and eosin staining, and transmission electron microscopy were employed. RESULTS: Corneal endothelial cells and Descemet's membrane were not detected in the central cornea, where there were immature cells with a fibroblastic configuration. The inner surface of the peripheral cornea was covered with cells containing pigment granules in the cytoplasm. Cell density in the central corneal stroma was relatively high. The diameter of the stromal collagen fibrils was not uniform. A mature collagen fibril-free area was also seen in the central corneal stroma. CONCLUSIONS: Differentiation of neural crest-derived cells in corneal stroma and endothelium might have been perturbed in the cornea of this patient with Peters' anomaly, inducing the defect in the corneal endothelium and the qualitative and quantitative abnormalities of the extracellular matrix.

Formation of corneal endothelium is essential for anterior segment development - a transgenic mouse model of anterior segment dysgenesis.

The anterior segment of the vertebrate eye is constructed by proper spatial development of cells derived from the surface ectoderm, which become corneal epithelium and lens, neuroectoderm (posterior iris and ciliary body) and cranial neural crest (corneal stroma, corneal endothelium and anterior iris). Although coordinated interactions between these different cell types are presumed to be essential for proper spatial positioning and differentiation, the requisite intercellular signals remain undefined. We have generated transgenic mice that express either transforming growth factor (alpha) (TGF(alpha)) or epidermal growth factor (EGF) in the ocular lens using the mouse (alpha)A-crystallin promoter. Expression of either growth factor alters the normal developmental fate of the innermost corneal mesenchymal cells so that these cells often fail to differentiate into corneal endothelial cells. Both sets of transgenic mice subsequently manifest multiple anterior segment defects, including attachment of the iris and lens to the cornea, a reduction in the thickness of the corneal epithelium, corneal opacity, and modest disorganization in the corneal stroma. Our data suggest that formation of a corneal endothelium during early ocular morphogenesis is required to prevent attachment of the lens and iris to the corneal stroma, therefore permitting the normal formation of the anterior segment.

Patología de córnea. Estafiloma corneal / Corneal pathology. Anterior staphyloma

Los estafilomas son ectasias corneales caracterizados por un gran alargamiento del segmento anterior. Generalmente dicha lesión corneal se encuentra con metaplasia queratinizada. Este proceso es originado por anomalías en el desarrollo del segmento anterior, se sugiere una falla en la migración de tejido mesenquimático. El pronóstico para la función visual es malo el tratamiento sólo mejora la cuestión estética

Efecto de la aplicación tópica de la Mitomicina C sobre el endotelio corneal de conejos albinos / Effect of external application of the Mitomicina C on the corneal endothelium of albino rabbits

Se desea investigar el efecto de la Mitomicina C en los tejidos subconjuntivales. Se utilizaron endotelio corneal de conejos albinos divididos en dos grupos. El grupo A reveló que la mitomicina C en gotas al 0,04 por ciento por 5 días BID, genera una alteración estadísticamente significativa en la hexagonalidad celular, densidad y en la morfología celular. En el grupo B, sometido a concentraciones de 0,04 por ciento intraoperatorio, con lavado después de tres minutos, se observaron cambios en la hexagonalidad celular estadísticamente significativos

Síndrome de Chandler. Presentación de un caso clínico / Chandler's syndrome. Case report

El síndrome iridocorneal endotelial incluye la atrofia esencial del iris, el nevo del iris o síndrome de Cogan-Reese y el síndrome de Chandler. Esta patología se caracteriza por anormalidades en la córnea, ángulo de la cámara anterior e iris. En síndrome de Chandler existe una membrana que crece hacia el ángulo produciendo alteraciones en el iris y glaucoma secundario entre otras. El pronóstico de esta enfermedad es incierto aun con tratamiento quirúrgico. Presentamos el caso clínico de una paciente con este síndrome y su evolución a 4 meses después del tratamiento

Efeitos do uso tópico da mitomicina C no epitélio corneano de coelhas: análise histopatológica pela morfometria / Effects of topical mitomicyn eye drops on corneal epithelium in the rabbit: a histhopathogical morphometric study

Este estudo foi realizado com o objetivo de avaliar a influência do uso tópico da mitomicina C, a 0,4 mgml, 0,2 mgml e 0,8 mgml, no epitélio corneano, com investigaçäo feita em uma populaçäo de coelhas. A mitomicina C e a água destilada (controle) foram instiladas duas vezes ao dia, por 4 dias, em olhos com superfície córneo-conjuntival íntegra e em olhos com defeito epitelial corneano central, com diâmetro de 7,75 mm. O epitélio corneano, de ambos os olhos, foi avaliado com exame histopatológico, complementado por análise morfométrica. A análise realizada pelo método do point couting, sob microscopia de luz, avaliou nas regiöes límbica, intermediária e central do epitélio corneano, a área do epitélio/ o número de núcleos/ a relaçäo núcleo-citoplasma e a área da célula epitelial. Nos olhos com superfície ocular íntegra, ocorreram variaçöes dos parâmetros morfométricos avaliados, notadamente na regiäo límbica. Nos olhos com defeito epitelial, as alteraçöes morfométricas mostraram variaçöes caracterizadas por alteraçäo da área epitelial (aumento no limbo e diminuiçäo nas regiöes intermediária e central), hipertrofia da célula epitelial, reduçäo da relaçäo núcleo-citoplasma e diminuiçäo do número de núcleos

Congenital hereditary endothelial dystrophy associated with glaucoma.

BACKGROUND: Three children, ranging in age from 2 to 6 months, had diffuse and homogeneously opaque corneas, clinically consistent with congenital hereditary endothelial dystrophy. Bilateral elevated intraocular pressure (IOP) was a feature in all three children. METHODS: Initially, all patients underwent glaucoma surgery to reduce IOP. Subsequently, a penetrating keratoplasty was performed in one eye of each patient to clear the visual axis. The excised corneal button was examined by light microscopy and by transmission and scanning electron microscopy. RESULTS: Postoperatively, all patients maintained clear corneal grafts. Results of histopathologic examination showed an absence of the endothelial cell layer in all patients. The presence of a variably thick collagenous layer posterior to the anterior banded zone of Descemet's membrane and the absence of endothelial cells were noted on transmission electron microscopy. Scanning electron microscopy confirmed absent, or scanty, and abnormal endothelial cells. CONCLUSION: The authors describe three patients with a clear association between congenital glaucoma and congenital hereditary endothelial dystrophy. This combination should be suspected where persistent and total corneal opacification fails to resolve after normalization of IOP.

Peters' anomaly: an unusual case.

The authors report on a case of congenital bilateral protruding corneal opacities. Clinical and histological examination was consistent with a diagnosis of Peters' anomaly with a defect in the endothelium and Descemet's membrane but without abnormalities of iris and lens. Corneal grafting was performed on both eyes. During a follow-up period of one year the corneas have remained clear. However, surgical intervention for glaucoma has been necessary.