Purpose: Unfavorable environmental conditions (excessiveUV-B exposure, lack of vegetation/shade, dry and windy climate, lack of eye protection, genetic factors, ascorbic acid (AA) partial nutritional deficiency, and corneal particle bombardment) trigger corneal inflammatory processes that play an important role in the generation/perpetuation of climatic droplet keratopathy. The present study was carried out to develop an experimental model of corneal erosion using Argon laser and to investigate its effects in animals fed with optimal and suboptimal doses of AA.
Methods: Ten healthy female guinea pigs aged 5 to 8 months old were used and randomly divided in 2 groups of 5 animals each, according to the level of AA in their diet: a high level AA diet group (HAA), and a low level AA diet group (LAA). The left eye of each animal (n = 10) was treated with Argon laser delivered through a slit-lamp and focused on the central cornea, with 15 spots of 50 microns each and an intensity of 350 mmWatts, while the right eye was not treated (controls, n = 10). Corneal changes were clinically evaluated by means of slit-lamp biomicroscopy and spectral domain optical coherence tomography at the following times: immediately before treatment, 1 hour, 18 hours, 6 days, 8 days, 15 days, and 21 days after treatment. Thereafter, the animals were sacrificed and the superficial layers of the cornea were studied by means of transmission electron microscopy (TEM) at each time points. Results: Corneal thickness was reduced in laser treated eyes during the first week and opacities appeared in the treated areas by day 15. Ultrastructural corneal epithelium and stroma modifications studied with TEM were present by day 8 in both groups of animals, being the changes much less pronounced in the HAA group.
Conclusions: An animal model of corneal thermal erosion using Argon laser was developed. The in vivo studies showed that the injured corneas completely recovered by day 7 without visible abnormalities. Ultrastructural changes were noticeable in animals under LAA diet.
