Pupil size, white-to-white corneal diameter, and anterior chamber depth in patients with myopia

To evaluate anatomical parameters in a population of patients with myopia.

Nine hundred sixty-four myopic eyes (-3.00 to -20.00 diopters [D] spherical equivalent refraction) were evaluated to measure mesopic and photopic pupil size with an infrared pupillometer; anterior chamber depth and white-to-white corneal diameter were obtained with Orbscan II (Bausch & Lomb). Correlation analysis was performed to evaluate the relationships among anatomical parameters of the anterior segment of the eye.

Average change in pupil size between mesopic and photopic conditions shows a uniform gap of 1.5 mm in patients aged 18 to 62 years with a slight insignificant trend to decrease with age. Photopic and mesopic pupil size were highly correlated (r=0.694, P<.001) and the difference between both measures was positively correlated with mesopic pupil size (r=0.207, P<.001) and inversely correlated with photopic pupil size (r=0.561, P<.001). Anterior chamber depth and white-to-white corneal diameter were positively correlated (r=0.389, P<.001). White-to-white corneal diameter and anterior chamber depth were not correlated with age (r=-0.096, P<.001) or anterior chamber depth (r=-0.183, P<.001-0.183) as a function of age.

Average difference between photopic and mesopic pupil size remained constant across the range of ages included in this cohort. A positive correlation was noted between anterior segment dimensions, and anterior chamber depth decreased with age.