Normal corneal thickness measurements in pigmented rabbits using spectral-domain anterior segment optical coherence tomography.

OBJECTIVE

To document the thickness of the central cornea in pigmented rabbits using spectral-domain anterior segment optical coherence tomography (AS-OCT).

ANIMALS STUDIED

Seventeen pigmented rabbits (6 male, 11 female, both eyes) were involved in this study.

PROCEDURES

Thirty-four eyes from healthy pigmented rabbits underwent a complete ophthalmologic examination, including AS-OCT. Eight radial scans, 6 mm in length and centered on the cornea, were obtained using the AS-OCT. Corneal thickness was automatically calculated using pachymetry software. Measurements were displayed as the mean and standard deviation for each of the 17 regions defined by the software. The regions were the center (1 mm radius, area a), the inner ring (2.5 mm radius, area b), the outer ring (3 mm radius, area c), and the eight radial scan lines in eight directions (Superior (1), SN (2), Nasal (3), IN (4), Inferior (5), IT (6), Temporal (7), ST (8)) with an angle of 45° between each consecutive scan line (a, b 1-8, c 1-8).

RESULTS

There was no statistically significance difference in corneal thickness between gender, eye, and the eight directions (P = 0.804, P > 0.05, P > 0.05). There was a statistical difference between the thickness in areas a, b, and c (P < 0.05). The corneal thickness increased gradually from the center to the periphery of the 6 mm measured. The center corneal thickness was 387 ± 19.8 μm for OD and 384 ± 20.2 μm for OS. The corneal thicknesses of the thinnest point of the right eyes (OD) and the left eyes (OS) were 376 ± 20.2 and 370 ± 16.8 μm, respectively. There was positive correlation between the thinnest point and area a in both the right eyes (r = 0.892, P < 0.001) and the left eyes (r = 0.832, P < 0.001).

CONCLUSIONS

This is the first documentation of the rabbit corneal thickness in vivo using the spectral-domain AS-OCT. Pigmented rabbit corneas were almost 150 μm thinner than human corneal values. Gender and eye were not associated with any statistical differences in central corneal thickness in this study.