Effects of age on ocular anterior segment dimensions measured by optical coherence tomography

Older subjects tend to have smaller ocular anterior segment. The present study aimed to measure anterior segment dimensions with optical coherence tomography (OCT) and quantitatively assess the effect of age and other factors.

Anterior segment OCT images were obtained in normal subjects residing in the greater Los Angeles area. Four line scans were acquired at the 90°, 45°, 0° and 135° meridians of each eye. Computer calipers acquired anterior segment dimensions of corneal diameter, anterior chamber width, corneal vault and anterior chamber depth on OCT images. Measurements from 4 meridians were averaged. Axial length and corneal power were measured by partial coherence interferometry. Univariate and multivariate analyses were performed to assess correlations.

Sixty-six eyes of 33 normal subjects (aged 22 - 65 years, 19 Asians, 14 Caucasians) were enrolled. For every 1 year of age, corneal diameter was 0.033 mm narrower (P < 0.01), anterior chamber width was 0.031 mm narrower (P < 0.01), corneal vault was 0.016 mm lower (P < 0.01), and anterior chamber depth was 0.025 mm lower (P < 0.01). Asian eyes had smaller corneal diameter (P = 0.035) and anterior chamber width (P = 0.015) compared with those of Caucasian eyes. Body height showed positive correlation with corneal diameter (0.039 mm per centimeter of height, P < 0.01) and corneal vault (0.024 mm per centimetre of height, P < 0.01). Gender did not have an independent effect on anterior segment dimensions.

Anterior segment dimensions were smaller in older subjects. Age-related changes may affect the tolerability of long-term implants such as phakic intraocular lens.