In normal subjects, the contribution of the anterior cornea to the overall ocular aberration remains reasonably stable over the normal interblink interval (approximately 4 seconds) but rises to levels which could perceptibly degrade retinal image quality under circumstances where the interblink interval is increased to exceed 10 seconds, as may occur during the use of visual display screens or when performing difficult tasks.

A significant induction of corneal HOAs still exists with the latest generation Schwind excimer laser. Linear regression analysis will help predict postoperative asphericity obtained when using LASIK for the correction of high myopia.

The 2-step technique improved the accuracy of excimer laser correction of post-PKP astigmatism.

Lipid peroxides are thought to be formed by free radicals and have been implicated in the pathogenesis of diabetes complications. A convenient and sensitive method for estimation of lipid peroxide concentration is the quantitative estimation of their metabolic end-product malondialdehyde (MDA) expressed in mmol/L using the thiobarbituric acid test (TBA-test). We have measured the serum concentrations of MDA in 60 well controlled type I diabetic patients (28 without retinopathy and 32 with retinopathy) and 13 age-matched healthy subjects. Patients with retinopathy showed significantly increased MDA level (2.65+/-1.00) compared to diabetics without retinopathy (1.80+/-0.81) and healthy controls (1.47+/-0.45). The serum levels of MDA correlated best with glycosylated haemoglobin (r=0.28), serum triglyceride concentration (r=0.29) and serum cholesterol concentration. (r=0.47). Increased lipid peroxides suggesting increased free radical activity is associated with retinopathy and this may have pathogenetic implications.

In this study the incidence of Demodex in patients with blepharitis was very high, when compared with normal subjects, showing a clear association between blepharitis and Demodex infestation. Treatment with mercury oxide ointment was satisfactory in controlling the infection, despite difficulty in its application and occasional toxicity.