Abstract
Purpose: :
Choroidal effusion has been hypothesized as a possible mechanism that can precipitate an acute attack of angle closure (AAC) in subjects at risk. A recent study on the water drinking test (WDT) reported changes in choroidal thickness induced by osmotic alterations in eyes with primary open angle glaucoma. The purpose of our study was to evaluate alterations in intraocular pressure (IOP), serum osmolality and choroidal thickness during the WDT in unaffected fellow eyes of subjects who have had a previous attack of AAC.
Methods: :
All participants underwent standardized eye exam including gonioscopy. At baseline, measurements of IOP, estimation of serum osmolality, and, macular imaging for choroidal thickness were captured using spectral domain optical coherence tomography. The subjects then underwent the WDT, after which serial measurements of IOP were taken at 15, 30 and 60 minutes. Repeat estimation of serum osmolality and macular imaging were performed at 30 and 60 minutes.
Results: :
Eleven eyes of 11 patients were studied. Mean age of the participants was 62.5+/-8.1 years. There were 4 males and 7 females. All eyes were fellow eyes of AAC. Baseline IOP was 13.3+/-2.9 mmHg, osmolality was 279.5+/-8.3 mmol/kg and choroidal thickness was 229.3+/-19.7 microns. At 15 minutes, the IOP (mmHg) was significantly higher compared to baseline (16.6+/-3.7, p=0.005), but at 30 and 60 minutes there was no significant difference (15.5+/-3.3, p=0.07 and 13.9+/-3.7, p=0.54 respectively). There was no significant difference in serum osmolality (mmol/kg) at 30 (276.4+/-6.8, p=0.17) and 60 minutes (276.4+/-6.9, p=0.37). Choroidal thickness (microns) was similar at 30 (229.1+/-21.2, p=0.87) and 60 minutes (229.6+/-19.6, p=0.55) compared to baseline.
Conclusions: :
In fellow eyes of subjects with AAC, a significant rise in IOP was demonstrated at 15 minutes after the WDT, but no difference was shown at 30 or 60 minutes. There were no detectable changes in serum osmolality or choroidal thickness.
Clinical Trial: :
Centralised Institutional Review Board, 2010/723/A
Keywords: intraocular pressure • choroid