Biometric evaluation of keratoconic eyes with slit lamp-adapted optical coherence tomography

To evaluate slit lamp-adapted optical coherence tomography for morphological imaging and morphometrical measurements in keratoconic eyes.

Using slit lamp-adapted optical coherence tomography, we examined 32 eyes of 20 consecutive patients with keratoconus and described morphological attributes of the cornea. Furthermore, in a subgroup of 19 eyes, we measured morphometrical values of the cornea and compared these values with those of an age-matched control group of 19 normal eyes.

Of the 32 keratoconic eyes, 23 eyes had marked corneal thinning of less than 450 μm, 18 eyes had central stromal scarring, and 3 eyes had intrastromal cysts from acute hydrops formation. Central corneal thickness was measured as 374 ± 106 μm in the group of 19 keratoconic eyes, compared with 503 ± 127 μm in the control group (P < 0.05); anterior chamber depth was 3.6 ± 0.4 mm versus 3.1 ± 0.4 mm (P < 0.05); anterior curvature mean radius was 7.2 ± 1.2 mm versus 8.6 ± 1.0 mm (P < 0.05); posterior radius was 5.5 ± 0.7 mm versus 6.8 ± 0.7 mm (P < 0.05).

This study provides further validation that anterior segment optical coherence tomography is a reliable method to assess important parameters for diagnosis and therapeutic outcome control of patients with keratoconus. This method may be particularly useful as a safe and well-defined preoperative diagnostic tool before keratoplasty or corneal cross-linking.