TY - JOUR T1 - Aqueous humour dynamics and biometrics in the ageing Chinese eye JF - British Journal of Ophthalmology JO - Br J Ophthalmol SP - 1290 LP - 1296 DO - 10.1136/bjophthalmol-2016-309883 VL - 101 IS - 9 AU - Tao Guo AU - Sruthi Sampathkumar AU - Shan Fan AU - Nathan Morris AU - Fang Wang AU - Carol B Toris Y1 - 2017/09/01 UR - http://bjo.bmj.com/content/101/9/1290.abstract N2 - Aims This study evaluates ocular biometrics and aqueous humour dynamics (AHD) in healthy Chinese volunteers to determine how the various ocular parameters interact to maintain physiological intraocular pressure (IOP) at all ages.Methods Sixty-nine volunteers enrolled in this cross-sectional study and were categorised into young (20–30 years) and old (≥50 years) groups. Measurements included IOP, ocular biometrics and AHD. Data were analysed using mixed model with random sampling to account for both eyes from the same individual. Spearman’s rank correlation with bootstrap resampling was used to find associations between parameters.Results Compared with young subjects, old subjects had significantly (p<0.05) thinner corneas (CCT; 549.7±5.7 vs 530.6±5.3 µm; mean±SEM), shallower anterior chambers (3.14±0.05 vs 2.37±0.05 mm) and slower aqueous flow (Fa; 3.0±0.1 vs 2.7±0.1 µL/min). Uveoscleral outflow slowed (Fu; 1.0±0.2 vs 0.7±0.1) but not significantly. A positive linear association between IOP and episcleral venous pressure was found (young: R2=0.16; old: R2=0.08). Negative correlation between Fa and CCT (R2=0.06) and positive correlation between Fa and outflow facility (R2=0.08) was found in old participants.Conclusions In the healthy ageing Chinese eye, IOP remains unchanged, while Fa slows, which is counterbalanced by slowing of Fu. Aqueous humour exits the eye preferentially through the trabecular route at all ages. Ageing is also associated with shallowing of the anterior chamber and thinning of the cornea. A slower Fa with lower outflow facility supports existence of autoregulatory mechanisms. ER -