Anterior chamber depth in Mongolians: variation with age, sex, and method of measurement

To document anterior chamber depth in a Mongolian population and quantify the variation in this parameter attributable to age, sex, and method of measurement.

Depth of the anterior chamber was measured by optical pachymetry in 1,242 subjects aged 10 to 87 years. Figures for "true" anterior chamber depth were calculated by subtracting central corneal thickness from the distance between the anterior corneal epithelium and anterior lens capsule. A-mode ultrasound was also used to measure the distance from anterior corneal epithelium to anterior lens capsule in 94% (942) of subjects aged 40 years and older. These ultrasound data were compared with measurements of the same distance obtained by optical pachymetry.

Mean anterior chamber depth in women was more shallow than in men of all ages (ANOVA, P < .0001), although this difference varied according to age. Mean anterior chamber depth decreased with age and was most accurately represented by a cubic function of age. This change was maximal between the ages of 30 and 60 years and equaled 0.15 mm per decade in men and 0.21 mm per decade in women. Mean depth of the anterior chamber measured by ultrasound was significantly less than the equivalent optical measurement (difference of 0.14 mm in right eyes, P < .001).

Mean anterior chamber depth in Mongolians decreases with age and is more shallow in women than in men. Ultrasound and optical methods of anterior chamber depth measurement yield significantly different results and are therefore not directly comparable.