Abstract
Purpose: :
Relevance of central corneal thickness (CCT) in applanation tonometry is widely acknowledged. Anterior Uveitis is often a recurrent and/or chronic condition, necessitating long term usage of topical steroids treatment. Major constitituent of corneal stroma which forms the bulk of corneal thickness is collagen. Corticosteroids alter collagen metabolism, and hence it is logical to have influence on corneal thickness and indirectly on applanation tonometry.
Methods: :
CCT as measured with Pachmate DGH 55 of 28 patients with recurrent/chronic unilateral anterior uveitis treated with corticosteroid drops(1% Prednisolone or 0.1% Dexamethasone or 0.1% Betamethasone) was compared with other unaffected and untreated eye. Mean patient age was 48± 16.5 years.Sex distribution was 18 males and 10 females. Mean duration of administration of topical steroids was 233 ± 106 weeks.
Results: :
Mean CCT of eyes treated with long term steroid drops were 528± 38µ as compared to 542±27µ in normal eyes. This was statistically significant (p=0.002) by students t test.CCT of eyes treated for less than 3 years(538± 26µ) were lesser thinner(524± 22µ) than those treated for more duration(p=0.006).There was no statistically significant difference in CCT between those eyes treated with above three types of steroids.
Conclusions: :
Above study suggests that long term use of topical corticosteroid alters the central corneal thickness. Measurement of intra ocular pressure in such eyes by applanation tonometry thus can be erroneous
Keywords: uveitis-clinical/animal model • intraocular pressure • drug toxicity/drug effects