Frequência da microftalmia associada à catarata congênita, sua frequência etiológica e o resultado visual pós-cirúrgico / Frequency and ethiological frequency of congenital cataract associated with microphthalmia and postoperative visual results

Resumo Objetivo: Determinar a frequência da microftalmia associada à catarata congênita e sua frequência etiológica. Comparar o resultado visual após a cirurgia da catarata congênita em olhos microftálmicos, com o resultado visual obtido em olhos não microftálmicos. Método: Estudo retrospectivo de 76 pacientes portadores de microftalmia e catarata congênita, selecionados após análise de 1050 prontuários dos pacientes atendidos no ambulatório de catarata congênita da UNIFESP. A microftalmia foi determinada pela ecobiometria ultrassonica. Exames oculares e complementares foram feitos para esclarecer a causa etiológica. O resultado visual pós- operatório do Grupo I (com microftalmia) foi confrontado com o resultado visual obtido no Grupo II (sem microftalmia). Resultados: O diâmetro ântero-posterior dos olhos microftálmicos variou de 13 à 21 mm. A frequência etiológica da catarata congênita associada aos olhos microftálmicos foi assim distribuída: doenças infecciosas (55,3%); seguidos de idiopáticas (26,3%), colobomas (7,9%), hereditárias (6,6%), persistência do vítreo primário hiperplásico (2,6%) e associada à síndrome de Lenz (1,3%) .A frequência da microftalmia foi de 7,23 %. 68,3% de olhos afácicos microftálmicos atingiram visão melhor e ou igual à 20/200. Conclusão: A frequência da microftalmia associada à catarata congênita foi de 7,23%. A maior frequência etiológica ocorreu nas doenças infecciosas (55,3%), Embora os olhos microftálmicos tenham tendência para piores resultados visuais quando comparados aos não microftálmicos, nesta pesquisa os olhos microftálmicos afácicos que atingiram visão melhor ou igual a 20/200 foram de 68,3%.

Abstract Objective: To determine the frequency of microphthalmia associated with congenital cataract and its etiological frequency. Compare the result of visual acuity in aphakic microphthalmus eyes, with the visual acuity result obtained in non microphthalmus eyes. Methods: Retrospective study of 76 patients with microphthalmia and congenital cataract, selected after analysis of 1050 medical records of patients seen in congenital cataract clinic of UNIFESP. All patients underwent complete ophthalmologic examination and microphthalmia determined by ultrasound biometry. Investigations were made to clarify the etiological cause. The postoperative visual outcome of Group I (with microphthalmia) was faced with the visual results obtained in Group II (control group without microphthalmia). Results: The anteroposterior diameter of microphthalmus eyes ranged from 13 to 21 mm. The etiological frequency of microphthalmia and congenital cataract was distributed as follows: infectious diseases (55.3%), idiopathic (26.3%), colobomas (7.9%), hereditary (6.6%), persistent hyperplastic vitreous (2.6%) and linked to the Lenz's syndrome (1.3%). The visual acuity in aphakic eyes that reached better view and or equal to 20/200 was 68.3%. Conclusion: The frequency of microphthalmia associated with congenital cataract was 7.23%. The etiological occurred more frequently in infectious disease (55.3%). The aphakics eyes with microphthalmia tend to have worse visual acuity results than the eyes without microphthalmia. If we consider the visual results same and above 20/200 as successful in this search, aphakic eyes with microphthalmia that hit these indices are 68.3%.

Evaluation of laminin expression during mouse lens development

Among the components of the extracellular matrix [ECM] and basement membrane [BM], laminitis heterotrimeric glycoprotein [laminin] and collagen type IV are the most important. In a previous study we have examined the role of collagen type IV in the developing lens capsule. The present study aims to determine the appearance and distribution of laminin in the BM and ECM of lenses during visual system morphogenesis. Pregnant Balb/C mice were randomly selected and maintained under normal conditions. The presence of a vaginal plug was assumed as day zero of pregnancy. From embryonic days 11 to 20, pregnant animals were sacrificed and their fetuses were collected for histotechnical prossessing. Our data revealed that laminin appeared during the early stage of gestation [day 12] in the BM of the anterior epithelial lens cells. The amount of laminin gradually increased in the ECM and posterioir lens capsule epithelial cells until days 14-18. After this period, a strongly positive laminin reaction was not observed in any part of the lens structure. These findings establish the importance of the laminin molecule in the developing optic cup [OC] and lens differentiation. It could be assumed that any changes in the presence of laminin during the critical period of eye development may result in visual system defects such as cataracts or congenital eye abnormalities

Growth of the human lens in the Indian adult population: Preliminary observations.

Context: The eye lens grows throughout life by the addition of new cells inside the surrounding capsule. How this growth affects the properties of the lens is essential for understanding disorders such as cataract and presbyopia. Aims: To examine growth of the human lens in the Indian population and compare this with the growth in Western populations by measuring in vitro dimensions together with wet and dry weights. Settings and Design: The study was conducted at the research wing of a tertiary eye care center in South India and the study design was prospective. Materials and Methods: Lenses were removed from eye bank eyes and their dimensions measured with a digital caliper. They were then carefully blotted dry and weighed before being placed in 5% buffered formalin. After 1 week fixation, the lenses were dried at 80 °C until constant weight was achieved. The constant weight was noted as the dry weight of the lens. Statistical Analysis Used: Lens parameters were analyzed as a function of age using linear and logarithmic regression methods. Results: Data were obtained for 251 lenses, aged 16–93 years, within a median postmortem time of 22 h. Both wet and dry weights increased linearly at 1.24 and 0.44 mg/year, respectively, throughout adult life. The dimensions also increased continuously throughout this time. Conclusions: Over the age range examined, lens growth in the Indian population is very similar to that in Western populations.

Trans-differentiation of iris pigmented epithelial cells of Euphlyctis cyanophlyctis tadpoles into lens in vitro.

Meshed pigmented iris epithelium along with neural retina of tadpoles of the frog Euphlyctis cyanophlyctis were found to undergo dedifferentiation and subsequently transdifferentiate into lens in culture medium. During lag period, depigmentation (dedifferentiation) occurred in many cells. When culture became confluent 3-4 weeks after seeding tiny lens like structures differentiated from foci of cultured pigmented iris epithelium cells. The percentage of lens formation was higher in vitamin A treated cases. The culture system appears to be a suitable for investigating the changes occurred during trans-differentiation of pigmented epithelial cells into lens.

Effect of Emblica officinalis (Gaertn) on lens regeneration in the frog, Rana cyanophlyctis (Schneider).

Emblica officinalis (Amla) accelerated cell proliferation and dedifferentiation of pigmented epithelial cells of dorsal iris and consequently induced lens regeneration in R. cyanophlyctis. Further it enhanced the percentage of lens regeneration not only in young tadpoles but also is adult frogs. Lens regeneration ability declined with the age of animals in both control as well as treated groups.