Comparison of Central Corneal Thickness after the Instillation of Topical Anesthetics: Proparacaine versus Oxybuprocaine

Choi, Kyoung Sub; Nam, Sang Min; Lee, Hyung Keun; Kim, Eung Kweon; Seo, Kyoung Yul

Abstract

PURPOSE
To compare changes in human central corneal thickness after instillation of proparacaine with those after oxybuprocaine instillation, over a period of 10 minutes. METHODS: Eighteen healthy young participants were recruited. Baseline central corneal thicknesses were measured every 30 seconds for 10 minutes using a noncontact specular microscope. Changes in central corneal thickness were measured every 20 seconds for 10 minutes after the administration of one drop of 0.5% proparacaine into the right eye, and one drop of 0.4% oxybuprocaine into the left eye. RESULTS: Mean baseline central corneal thickness was 531 +/- 45 micrometer in the right eye and 531 +/- 42 micrometer in the left. The central corneal thickness after proparacaine instillation increased to 8.6 micrometer (4.5-12.6 micrometer, 95% CI) and then returned to baseline within 80 seconds. Central corneal thickness after oxybuprocaine instillation increased to 7.7 micrometer (3.6-11.2 micrometer, 95% CI) and then returned to baseline within 80 seconds. There was a second transient increase about 5 minute after proparacaine instillation but no additional transient increase after oxybuprocaine instillation. CONCLUSIONS: The severity of oxybuprocaine's effect on central corneal thickness is similar to that of proparacaine. Central corneal thickness instability may occur for 5 minutes after proparacaine administration. Therefore, changes in central corneal thickness after topical anesthetics instillation should be considered when measuring central corneal thickness.