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The aim of the present study was to investigate the regenerative ability of the central corneal epithelium in an in vivo situation, as previous studies have been contradictory regarding the proliferative potential of these cells. Paracentral ringshaped defects were made in rat corneal epithelium, using filter paper soaked in n-heptanol. Cell counts, labelling indices and mitotic rates were measured in sections from the corneal and the adjacent conjunctival epithelium 12 and 28 h after the injury. The cell counts indicated that also central corneal epithelial cells migrate in the early phase of wound healing. No proliferative response was seen in the central corneal epithelium after 12 h. At 28 h both the peripheral and central corneal cells showed an enhanced labelling index, while the mitotic rate only was increased in the periphery. Different cell cycle times and different levels of differentiation of the cell population across the cornea may explain the delayed proliferative response in the central cornea.

Central corneal epithelial defects with diameter 3.5 mm were made with n-heptanol in the right eyes of rats. Erosions of the same size were made by mechanical scraping in the left eyes of the same animals. All the erosions were covered by epithelium after one day. After one day the mitotic rate and the labelling index were higher in the n-heptanol treated corneas compared to the mechanically abraded ones. Both methods produced similar mitotic rates and labelling indexes after 3 and 12 days. The results from wound healing studies using n-heptanol or mechanical scraping are therefore not entirely comparable because of the different regenerative responses after one day. However, the n-heptanol method is easier to perform and to standardize, and is therefore preferable.

PURPOSE The present study was to investigate, using cell kinetic methods, whether previous excimer laser treatment affected healing of later corneal epithelial erosions. METHODS The right eyes of rats underwent central excimer corneal stromal-epithelial ablations (ArF 193 nm, 228 pulses, diameter 3,5 mm, 17,3 mJ per pulse, depth about one third of corneal thickness) and were allowed to heal for 15 weeks. Then central circular epithelial abrasions (diameter 3 mm), using N-Heptanol and mechanical debridement, were made on both corneas. The rats were killed 1,2,4 and 6 days after the last treatment. The central stromal thickness, the epithelial cell density, the labelling index (LI) and the mitotic rate (MR) of the peripheral, the midperipheral and the central areas of the corneal epithelium were calculated for each timepoint. RESULTS The central stromal thickness increased equally in the two groups the first day after making the erosion, normalising in both groups during the following days. The corneal epithelium was restored at the same rate in both groups. The cell number per microscopic visual field, the LI and the MR were very similar for the two groups at all timepoints. CONCLUSION Previous excimer laser treatment does not seem to interfere with healing of later epithelial erosions, when studied with cell kinetic methods.

In the present transmission electron microscopic study, regenerating rat corneal epithelium is examined at three different time points after chemical abrasion. Four days after the initial injury classical signs of regeneration are observed. At day 6 regeneration is less pronounced and epithelial differentiation dominates the morphological picture. Many basal cells are swollen and single electron-dense basal cells have a shrunken morphology (dark cells). Intercellular cytoplasmic sacs are common and some appear to be phagocytosed. At day 8 there are no signs of regeneration and neither dark cells nor swollen cytoplasmic sacs are seen. No signs of intraepithelial inflammation are seen at any time. "Odland"-like granules, which possibly play a role in epithelial desquamation, occur suprabasally in large numbers at all time points. We believe the simultaneous presence of dark cells and phagocytosis at day 6, without signs of inflammation, indicates ongoing apoptosis. Intraepithelial cell loss might explain the discrepancy between an increased proliferation rate and the absence of hyperplasia which has been reported at this time point.

PURPOSE Study the efficacy and safety of a combined procedure for coexisting cataract and open angle glaucoma. METHODS Forty eyes of 33 patients with cataract and coexisting open angle glaucoma underwent phacoemulsification and trabeculectomy with Crozafon-De Laage punch. Data was recorded from the patients' hospital files and from a questionnaire answered by the patients' regular ophthalmologist. RESULTS After a mean follow-up time of 20.6 months (SD 4.9, range 12-31) the mean reduction in number of anti glaucoma drugs was 1.2 (SD 1.2) from 2.6 (SD 0.71) before operation to 1.4 (SD 1.12) at last visit (p