Effects of new biomimetic regenerating agents on corneal wound healing in an experimental model of post-surgical corneal ulcers.

OBJECTIVE: The purpose of this study is to assess the effectiveness of the topical application of cacicol regenerating agent (RGTA) in an experimental model of corneal ulcer after photorefractive keratectomy (PRK) in mice. METHODS: Mice were subjected to PRK surgery with a 2.0mm ablation zone on the central cornea and 45mm of depth on a VISX Star S2 excimer laser. Corneas were treated topically with cacicol drops 1hour and 48hours after injury. Control groups received balanced salt solution (BSS) in the same dosage. Clinical and histopathological events were evaluated at 1, 2, 3 and 7 days after surgery. Sections obtained through the central region of the corneas were used to analyze the histopathological events of injured and healed corneas. αSMA (myofibroblast transformation), E cadherin (assembly of epithelial cells) and neuronal class III ß-tubulin (innervation) were performed. RESULTS: Corneas treated topically with cacicol for 7 days showed a greater degree of transparency compared to controls. cacicol treated corneas showed improved epithelial cytoarchitecture. Analysis of αSMA profiles in the stroma showed that cacicol reduced or delayed the presence of myofibroblasts in the stroma compared to BSS (P<0.001). Finally, a putative neuroregenerative effect of cacicol was found in corneas subjected to an experimental PRK lesion. In some cases some interindividual variability could be observed due to the design of the experimental model. This is a limitation to consider, despite the statistical significance of the data. CONCLUSIONS: In a model of laser induced surgical lesions in the cornea, topical application of an RGTA (i.e. cacicol) could be involved in avoiding myofibroblast scarring formation and promoting nerve regeneration.

[Laser ray tracing to measure optical aberrations in eyes with contact lenses]. / Aberraciones ópticas en ojos con lentes de contacto medidas con el sistema de trazado de rayos.

PURPOSE: To evaluate the impact of disposable soft contact lenses upon visual performance by comparing the optical aberrations of myopic eyes with and without the use of contact lenses. METHOD: The optical aberrations of a set of 18 eyes were measured by a laser ray tracing system, an objective measurement method, enabling comparison of the findings of the naked eye, the eye plus a test lens, and the eye plus a disposable contact lens. RESULTS: There was a large variability among subjects, but the general tendency was that test lenses did not modify aberrations, whereas contact lenses tended to increase the ocular aberrations for large pupils by an average of 40%. There was a lower increase for smaller pupils. CONCLUSION: This study predicts there will be no significant adverse effects on the quality of vision from the use of disposable contact lenses worn under daylight conditions, but a small decline in night vision.

[Refractive surprise after LASIK]. / Sorpresa refractiva tras LASIK.

CASE REPORT: A female patient underwent laser in situ keratomileusis (LASIK) in both eyes. The final degree of astigmatism in her left eye was double the preoperative value due to an error in data management. Complex surgery to both eyes was necessary to resolve the mistake. DISCUSSION: Complications in refractive surgery can occur, however errors in data management must be minimized by double-checking. Solutions to resolve the errors made can be difficult and the entire staff must share responsibility to avoid these undesirable outcomes.

HLA typing in patients with ocular manifestations of Stevens-Johnson syndrome.

BACKGROUND: Stevens-Johnson syndrome (SJS) is an acute, self-limited, inflammatory disorder of the skin and mucous membranes. With ocular involvement, SJS has been associated with the class I human leukocyte antigen (HLA)-Bw44. This study examined HLA class II associations in patients with SJS with ocular involvement to help identify possible molecular genetic mechanisms underlying disease susceptibility/resistance. METHODS: Twenty-three white patients with ocular complications secondary to SJS had HLA class II typing performed using polymerase chain reaction-based molecular techniques. Genotype frequency was compared with results obtained from 175 control subjects. RESULTS: HLA-DQB1*0601 was present in four (17%) patients with SJS and in five (3%) control subjects (P < 0.05; relative risk = 7.2). There was no association with HLA-DQB1*0301, which previously has been been strongly associated with recurrent erythema multiforme. None of the class II antigens tested appeared to offer a protective effect against the development of disease. CONCLUSION: HLA-DQB1*0601 was found in a significantly disproportionate number of white patients with SJS and ocular complications. The presence of this allele may confer an increased risk for the development of SJS with ocular complications and provides further evidence for an underlying immunogenetic susceptibility to the development of this disease.