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Ocular dryness symptoms occurred commonly after PRK and LASIK. Symptoms suggestive of mild recurrent erosions included sharp pains, the sensation of the eyelid sticking to the eyeball, and soreness of the eyelid to touch, a previously unrecognized symptom of this condition. These symptoms occurred commonly after excimer laser procedures but were significantly more common, more severe, and more prolonged after PRK. The presence of these symptoms had a significant effect on patient satisfaction.

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The 100-microm PTK ablation resulted in significantly more corneal scarring than the 15-microm PTK ablation. Even though there was no immunohistochemical difference in the pattern of TGFbeta and bFGF expression after deep and shallow ablations, there was an association between the expression of the growth factors and corneal scarring after excimer laser keratectomy.

A method is developed for quantifying the strength of the moiré effects known as Glass patterns. Unpaired randomly placed dots are added to the pattern while the discriminability d' of the degraded pattern is determined in a yes-no test. For a given discriminability the number of pairs required increases in direct proportion to the number of random dots. A model is developed based on the ideal discrimination of an excess of oriented pairs. Results conforming to Weber's law are predicted; the dependence of d' on the amount of noise and the number of point pairs is also predicted. A numerical constant derived from the model provides a measure of the strength of the moiré effect of a chosen pattern. Note that, for this task, statistical considerations predict Weber's law, not the square-root law, as a limit, and this result holds whenever second-order structure is detected in the image.