Corneal Epithelial Thickness Profile in Healthy Portuguese Children by High-Definition Optical Coherence Tomography

Abstract

Introduction and Objective To evaluate corneal epithelial thickness (ET) and corneal thickness (CT) profiles in healthy eyes of Portuguese children and provide information to establish the first normative Caucasian database for these age group. Methods Sixty healthy eyes of 60 children aged between 8 and 18 were evaluated using the Cirrus high-definition optical coherence tomography device. The average ET and CT were assessed using Cirrus Review Software with predefined concentric corneal ring-shaped zones. Specific regions of ET (central, superior, inferior, temporal, nasal, superonasal, inferotemporal, superotemporal and inferonasal) were also assessed. The mean ET, the mean CT and the difference of ET in corresponding octants were compared by gender. Correlations between central epithelial thickness (CET), age and refractive error were evaluated. Results and Discussion The average ET was lower in the peripheric zones, whereas the average CT was higher. ET was thinner in the superior area than in the inferior (p<0.05). ET was thicker in boys than in girls (p<0.05), but CT did not differ. CET was not correlated with older age or refractive error. Conclusion Optical coherence tomography analysis of ET reveals that it is thinner in the periphery, where the CT is thicker. Unlike CT, ET seems to be influenced by gender. ET profile proved to be a useful tool in keratoconus diagnosis and subclinical keratoconus detection in adults. As epithelial changes occur early in the disease and keratoconus is more aggressive in pediatric population, a normative database of ET profile could contribute to enhance early recognition of the disease in this age group.

Corneal Epithelium Thickness Profile in Normal Adults

“…Mean epithelial thickness was signi cantly higher in male than female in all three zones (central, paracentral, and peripheral, p < 0.05, all). This is consistent with previous studies (4,5,17,28). It has been postulated that males have thicker CET than females because the total corneal thickness was reported to be thicker in males than in females (29,30).…”

“…Consistent with previous data (3,4,5,13,14,17,25,26), our ndings demonstrated that the corneal epithelium was nonuniform. The superior epithelium was thinner than the inferior one.…”

“…In keeping with previous studies (17,25,26,27), we found that the nasal epithelium was thicker than the temporal epithelium, with the highest difference reported in the peripheral area (2 ± 3 µm). It has been postulated that the nasal cornea is more protected from tarsus rubbing than the nasal cornea due to the outer canthus laying higher than the inner canthus (26).…”

“…ET and CT were acquired with the anterior segment spectral-domain Cirrus 5000 HD-OCT (Carl Zeiss Meditec, Germany). In line with the method described previously (17), the cornea lens attachment was used for the pachymetry map and HD cornea scans. The subjects were positioned on the headrest looking to the xation light and the image was centered on the pupil center.…”

Systematic detection of keratoconus in OCT: corneal and epithelial thickness maps

“…To the authors' knowledge, there are a few studies using this OCT device in healthy adults and children, and our current study is the first for KC detection. [26][27][28] However, it has been shown in studies conducted with different OCT devices that these parameters differ significantly in KC eyes compared with healthy ones. 10,11,[14][15][16]18,29 Pachymetric minimum and min-med indicates focal thinning in the cornea; pachymetric SN-IT detects asymmetric thinning; and epithelial SN-IT measures asymmetric thinning of the corneal epithelium.…”