Aqueous humor dynamics in the aging human eye

• Published in: American journal of ophthalmology Vol. 127; no. 4; pp. 407 - 412
• Main Authors: Toris, Carol B, Yablonski, Michael E, Wang, Yun-Liang, Camras, Carl B
• Format: Journal Article
• Language: English
• Published: New York, NY Elsevier Inc 01.04.1999; Elsevier
• Subjects: Adult; Aged; Aging - physiology; Anterior Chamber - physiology; Aqueous Humor - metabolism; Biological and medical sciences; Eye and associated structures. Visual pathways and centers. Vision; Female; Fluorophotometry; Fundamental and applied biological sciences. Psychology; Humans; Intraocular Pressure; Male; Middle Aged; Sclera - blood supply; Sclera - physiology; Tonometry, Ocular; Uvea - physiology; Venous Pressure; Vertebrates: nervous system and sense organs; Human; Exploration; Aqueous humor; Eye; Visual system; Dynamics; Uvea; Volume; Young adult; Anterior chamber; Elderly; Age; Sclera; Intraocular pressure
• ISSN: 0002-9394; 1879-1891
• DOI: 10.1016/S0002-9394(98)00436-X

Purpose: Healthy subjects were recruited to identify normal, age-associated changes in intraocular pressure and aqueous humor dynamics. Methods: Normal healthy subjects from two age groups were enrolled in the study: (1) those from 20 to 30 years of age (n = 51) and (2) those 60 years of age and older (n = 53). Intraocular pressure was measured by pneumatonometry, tonographic outflow facility by pneumatonography, and episcleral venous pressure by venomanometry. Aqueous flow and outflow facility were determined by a fluorophotometric technique. Uveoscleral outflow and anterior chamber volume were calculated. Results from the older group were compared with those from the younger group by means of unpaired, two-tailed t tests. Results: Compared with the younger group, the older group showed significant differences as follows: smaller anterior chamber volume (160 ± 39 vs 247 ± 39 μl; mean ± SD; P < .00001), reduced aqueous flow (2.4 ± 0.6 vs 2.8 ± 0.8 μl/minute; P = .002), and reduced uveoscleral outflow (1.10 ± 0.81 vs 1.52 ± 0.81 μl/minute; P = .009). Conclusions: In the healthy aging eye, there is a reduction in the production of aqueous humor and a reduction in its drainage through the uveoscleral outflow pathway.