Aqueous protein concentration in rhegmatogenous retinal detachment.

Changes in aqueous protein concentration (APC) in rhegmatogenous retinal detachment (RD) were investigated. A 6-month prospective study was carried out in 40 unilateral RD patients who underwent scleral buckling procedures with cryotherapy, and a retrospective examination was performed in another 40 patients who had undergone successful retinal reattachment at least 2 years previously. Before the surgery, the APC in the RD eyes was more than twice as high as that in the contralateral control eyes. The surgery caused a further increase in APC, and the peak was observed at the 2nd postoperative week. The APC values decreased to a stable level 3 months postoperatively, but remained significantly higher than those of the control eyes. A statistical analysis revealed the following clinical factors to have a significant correlation with the increase in APC: 1) before surgery, age, extent of RD, balloon-shaped RD, presence of retinal tear rather than hole, and decreased preoperative intraocular pressure; 2) in the early postoperative period, age, size of retinal breaks, and number of cryoapplications; and 3) in the late postoperative period, age, extent of RD, and performance of scleral encircling procedure. These findings would suggest that different mechanisms are responsible for the increase in APC in each period, including 1) a reduction in the aqueous bulk flow; 2) disruption of the blood-retinal barrier caused by cryotherapy, or dispersion of subretinal protein into the vitreous cavity during the surgery; and 3) a decrease in aqueous flow rate following buckling procedures, and alteration of the blood-aqueous barrier function induced by changes in anterior uveal blood circulation.