[Measurement of the subretinal fluid volume using B-scan ultrasonography. Report 2. Measurement of the decrease rate...

I have previously reported the use of video-ultrasonography and an image computerized system to measure the volume of subretinal fluid (SRF). This measurement system was now used for 19 eyes with rhegmatogenous retinal detachment during absolute rest in bed for 24 hours and double patching. The mean age was 55 years (range, 18-69 years). The retinal detachment involved two quadrants or less of the retina in all eyes. The decrease rate of SRF was 0.051 +/- 0.033 microliter/mm2/hour (mean +/- standard deviation); 0.074 +/- 0.033 microliter/mm2/hour in 9 eyes in which the duration of retinal detachment was 14 days or less and 0.030 +/- 0.009 microliter/mm2/hour in 4 eyes in which the duration was 15 days or more. The rate was 0.032 +/- 0.009 microliter/mm2/hour in 3 eyes with atrophic holes. Three eyes with macular holes, which had retinal detachment underlying extensive staphyloma showed a rate of 0.028 +/- 0.022 microliter/mm2/hour. Though absolute rest in bed and double patching cannot completely block a transfer of fluid from vitreous to subretinal space via retinal break, the decrease rate of SRF appears to reflect the absorption of SRF across the retinal pigment epithelium.