Caucasians may be less predisposed to developing glaucoma due to slower aqueous flow and faster uveoscleral outflow rates compared with their Asian (particularly Chinese) counterparts, a study in the British Journal of Ophthalmology reports.

A team of Chinese and US researchers compared data from two independent studies with identical designs. Cohorts included young adults between the ages of 20 and 30 (32 Chinese and 39 Caucasians) and adults older than 50 (37 Chinese and 46 Caucasians). Investigators evaluated the parameters of aqueous humor dynamics and ocular biometrics and compared the groups.

They found key differences in young adult Caucasians compared with similarly aged Chinese patients, including thinner central corneas (−29.27µm), lower intraocular pressure (−2.33mm Hg), larger anterior chamber volume (28.78µL) and faster uveoscleral outflow rate (0.82µL/min). The study also noted differences in older adult Caucasians compared with similarly aged Chinese participants, including a slower aqueous flow rate (−0.28µL/min,), lower IOP (−1.97mm Hg) and larger anterior chamber volume (33.15µL). Looking at race only, Caucasians had slower aqueous flow rate (−0.22µL/min), thinner corneas (−0.52µm), lower IOP (−2.11mm Hg,), higher anterior chamber volume (30.39µL) and faster uveoscleral outflow rate (0.63 µL/min).

Differences in aqueous humor dynamics and biometrics between Caucasian and Chinese adults include larger anterior chamber volume, which may contribute to the wider angles reported in Caucasians, researchers noted. Additionally, slower aqueous flow rates coupled with faster uveoscleral outflow rates may factor into Caucasians’ lower IOP and overall risk of glaucoma, the investigators concluded.

Fan S, Guo T, Chen B, et al. Differences in ocular biometrics and aqueous humour dynamics between Chinese and Caucasian adults. Br. J Opthalmol. March 19, 2109. [Epub ahead of print].