An Evaluation of Central Corneal Epithelial Thickness and Central Corneal Thickness Determined On Optic Coherence Tomography Before and After Applanation Tonometry

Abstract

Objective: To determine the changes in corneal epithelial thickness and central corneal thickness using optic coherence tomography taken after Goldmann applanation tonometry measurements. Material and Methods: The study included 25 patients who presented at our clinic for routine ophthalmological examination. Before taking tonometry measurements of the patients, epithelial corneal thickness and central corneal thickness values were determined using optic cohence tomography (OCT). The intraocular pressure (IOP) was measured with tonometry and then the corneal OCT measurements were repeated. All the OCT and tonometry measurements were taken by the same clinician. Results: Evaluation was made of 25 patients comprising 18 males and 7 females with a mean age of 36.6 years (range, 17-55 years). The mean epithelial corneal thickness was 52.58 microns before the applanation tonometry measurement, and 52.02 microns after the tonometry (p=0.059). Central corneal thickness was measured as mean 530.96 microns before tonometry and 529.88 microns after (p>0.05). No statistically significant difference was determined in the changes of both measurements. Following tonometry, a change was seen in corneal epithelial thickness, but not of a statistically significant level (p=0.059). Conclusion: The study results showed no statistically significant difference in the measurements of corneal epithelial thickness and central corneal thickness following applanation tonometry. Although not statistically significant, the difference seen in thickness indicates desquamation in the epithelial cells as a result of the procedure. This may cause complaints such as a reduction in visual acuity and the feeling of burning or pricking in the eye. If glasses are to be prescribed for patients, this should be taken into consideration and the examination should be made before the tonometry measurement. To the best of our knowledge, there has been no previous study in literature of central corneal epithelial thickness measured before and after tonometry, and therefore the results obtained in this study are the first on this subject.