Factors Affecting Aqueous Humor Outflow Facility in Patients with Uveitis

Objective: To determine the clinical variables that influence aqueous outflow facility (Co) and intraocular pressure (IOP) in uveitis. Uveitic glaucoma is potentially blinding and occurs in 17-46% of chronic uveitis patients. Uveitic activity causes fluctuating IOP due to decreased Co, increased uveoscleral outflow or decreased aqueous production. Specific Aim 1: To evaluate the risk factors for high IOP and low Co in uveitis Hypothesis: Decreased Co and increased IOP will occur with increasing anterior chamber (AC) flare, AC cells, degree of synechial angle closure, increased duration of disease, higher uveitis activity and increasing steroid use Specific Aim 2: To determine prospectively the effect of AC flare on Co and IOP in "quiescent" uveitis Hypothesis: AC flare even in the absence of AC cells will cause progressive decline in Co. Methods: In this proof of concept study, thirty consecutive patients with acute or chronic uveitis will be recruited from the uveitis clinic. Ten patients with "quiescent" uveitis (no AC cells) will be recruited for the prospective arm and followed every 2-3 months for 3 visits. Co will be measured using 2-minute pneumatonometer tonography. The effect of risk factors on IOP and Co in uveitis will be studied using generalized linear modelling techniques. These risk factors include AC flare (using the laser flare meter), AC cells, degree of angle closure (by gonioscopy), duration of disease, disease activity and corticosteroid use within the last year. In the prospective study, the patients will be divided into subgroups with low flare (\< 20ph/ms) and high flare (≥ 20 ph/msec) and the change in Co and IOP will be analyzed. Impact: This will be the first study to systematically analyze the risk factors for decrease in Co and increase in IOP in uveitis and to prospectively evaluate the effect of AC flare on Co. Proof that AC flare can damage the trabecular meshwork will corroborate previous experimental evidence and change the para