Central corneal thickness in a pediatric population using a noncontact specular microscope: a study of 405 cases

Aim: Central corneal thickness has become very important in the interpretation of intraocular pressure. The aim of this study was to correlate pachymetry values in a pediatric population with age, sex, and refraction. To our knowledge, the scientific literature has not reported such information. Patients and method: This prospective study was conducted from May 2005 to November 2006 and included 405 eyes (1186 eyes in boys and 219 eyes in girls) in children undergoing a general pediatric ophthalmologic visit. Patient age ranged from 3 to 16 years; three age groups were formed: 3-4 years, 5-9 years, 10-16 years. Objective refraction with cycloplegic was measured using a Nidek (R) ARK 700 A autorefractometer and three refraction groups were formed. Pachymetry measures were taken using the Topcon (R) SP 2000P specular microscopy. Exclusion criteria were a history of ocular surgery, lens wearers, and any disease that could alter the cornea. Results: The mean age was 8.21 +/- 3.55 years, the mean refraction was +1.24 +/- 4.02 D. The mean central pachymetry was 529 +/- 32 mu m: 534 +/- 31 mu m in the male group and 524 +/- 31 mu m in the female group, establishing a difference in pachymetry with no differences in refraction or age between the two groups. In the refraction groups, we found a significant difference in pachymetry between emmetropic (523 +/- 33 mu m) and hyperopic (533 +/- 31 mu m) groups and between hyperopic and myopic groups (520 +/- 32 mu m) (p =0.005). There was no difference between emmetropic and myopic groups (p =0.902), nor in pachymetry between age groups (p =0.086). Discussion: Except for differences found in refraction groups, the results reported herein were similar to those found with the ultrasonic method (the reference method), but they had been obtained under general anesthesia in most studies. Conclusion: Even though this is not the reference method of pachymetry measures, it seems more appropriate for children, because it is reliable, the measurements are taken quickly, they are noninvasive, and they do not cause the child undue stress (noncontact method).