Association of Corneal Thickness and Intraocular Pressure

I read with great interest the article by Nemesure et al¹ inthe February 2003 issue of the ARCHIVES. I commend the authors on their studyof race in regard to an association between central corneal thickness (CCT)and intraocular pressure (IOP). However, I would hesitate to accept the authors'conclusion that there is no association between CCT and IOP in the black populationof Barbados, West Indies.

Participants in the study were not excluded on the basis of historyof ocular incisional surgery, trauma, or corneal disease. This omission isa substantial one in the study methods because previous eye surgery or cornealdisease can substantially change corneal shape and thickness, thereby alteringCCT measurements. The study also made no mention of what type of pachymeterwas used for the CCT measurements or how often it was calibrated. Furthermore,examiners of CCT were not masked to participant IOP. Pachymetry measurementsare substantially altered by probe placement, which necessitates masking ofCCT examiners to eliminate potential observer bias.