gms | German Medical Science

Dry-Eye syndrome (DES) covers a wide range of disturbances related to the ocular surface which are treated symptomatically only. Changes in corneal thickness and optical density, however, have not been investigated in this context in detail before.

For this purpose 103 patients with varying periods of dry eyes have been enroled in the study and their corneas have been documented with Scheimpflug photography. Subsequent densitometric evaluation was performed in 5 individual layers, the epithelium (1), Bowman's layer (2), stroma (3), Descemet's membrane (4) and the endothelium (5). Density data recorded were compared to age-matched normal cases. In addition, several dry-eye medications have been tested in their effect on corneal thickness and density.

DES patients showed a significant decrease in thickness of the cornea as compared to the normal controls which showed an age-related increase. Optical density of corneal layers 1, 2 and 4 were significantly lower than in normal controls. Diabetic patients with DES showed a tendency towards higher density values especially in layer 5. Among the drye-eye medications tested those formulated on the basis of hydroxy-polymethyl-cellulose (HPMC) demonstrated a trend to reverse DES effects on corneal optical density.

Our data demonstrate that DES patients do no longer have the age-related increase in corneal thickness and together with the reduced density of the 2 thickened basement membranes present in the eye, this could point at disturbances of cellular proliferation in the cornea in DES. Diabetic patients with DES showed an opposite trend. Only HPMC based dry-eye medication (Artelac^®, Sic-Ophthal^®, Lacrisic^®) demonstrated a measurable effect, the other medications tested (Lacophthal^®, Oculotect^®,Protagent^®, Vidirakt^®, Vidisept^®, Lacrimal^®, Liquifilm^®, Siccaprotect^®, Vidisic^® Augengel, Visc-Ophthal^®, Thilo-Tears^®) showed no detectable effect on the parameters investigated.