Fluorophotometry was carried out in nine cases of unilateral non-traumatic rhegmatogenous retinal detachment successfully treated by a combination of local buckling and an encircling procedure with a silicone band. After topical instillation of fluorescein the change in its concentration in the anterior chamber was followed, from which the loss rate of the dye from the anterior chamber (k0) and the cornea-aqueous transfer coefficient (kc.ca) were estimated. The thickness of the cornea and the anterior chamber volume were also measured, and the aqueous flow rate and the corneal endothelial permeability were calculated in individual eyes. The examinations performed 4-18 months after operation showed that the aqueous flow rate in the operated eye fell to 85 (SD 12)% of that in the fellow control eye (p less than 0.005). In the operated eye the anterior chamber volume also fell significantly, and the corneal endothelial permeability may have decreased. Ocular hypotension after the detachment surgery with encirclement was attributable to a decrease in the aqueous flow rate.