RESUMO
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.
Assuntos
Córnea/ultraestrutura , Ovinos/anatomia & histologia , Fatores Etários , Animais , Argentina , Lâmina Limitante Anterior/ultraestrutura , Córnea/inervação , Substância Própria/citologia , Substância Própria/inervação , Substância Própria/ultraestrutura , Lâmina Limitante Posterior/citologia , Lâmina Limitante Posterior/ultraestrutura , Células Endoteliais/ultraestrutura , Endotélio Corneano/citologia , Endotélio Corneano/ultraestrutura , Epitélio Corneano/ultraestrutura , Feminino , Processamento de Imagem Assistida por Computador , Microscopia Confocal/veterinária , Microscopia Eletrônica de Transmissão/veterináriaRESUMO
PURPOSE: To evaluate and compare the effect of hinge position and flap thickness on recovery rate of corneal sensation after (LASIK). DESIGN: Prospective, randomized clinical study. METHODS: Forty eyes of 40 patients underwent LASIK to correct myopia ranging from -1.00 to -2.50 diopters. Corneal sensitivity was measured preoperatively and each month after surgery until recovery to preoperative level. The nasal-hinged ACS microkeratome (NH) with depth plates of 130 and 160 microm and the superior-hinged Hansatome microkeratome (SH) with depth plates of 160 and 180 microm were used for corneal flap creation. The eyes were divided into four groups according to the hinge position and depth plate (DP): group 1, NH and 130 microm DP; group 2, NH and 160 microm DP; group 3, SH and 160 microm DP; group 4, SH and 180 microm DP. RESULTS: Corneal sensitivity returned to preoperative level after 3.7 (+/- 0.4), 4.4 (+/- 0.6), 5.4 (+/- 0.8), and 5.8 (+/- 0.9) months, respectively, in groups 1, 2, 3, and 4. Statistically significant differences were found between groups 1 and 2, but not between groups 3 and 4. Corneal sensitivity gradually returned to preoperative levels in all groups. Sensitivity of the hinge area was higher than other areas at every time point. CONCLUSIONS: The results suggest that after LASIK, hinge position and flap thickness seem to be important factors in the rate of return of corneal sensitivity. A thin flap with a nasally placed hinge is associated with the most rapid recovery of corneal sensitivity.