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Justin Rome, Shani Reich, Elliott Brodbaker, Pearl S Rosenbaum, Jonathan Levine, Nathaniel Nataneli; Effect of Pan Retinal Photocoagulation on Anterior Chamber Depth and Volume: A Model for Evaluation of Choroidal Microeffusion. Invest. Ophthalmol. Vis. Sci. 2014;55(13):3896.
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© ARVO (1962-2015); The Authors (2016-present)
A rare, visually-threatening complication of Pan Retinal Photocoagulation (PRP) is choroidal effusion. The purpose of this study is to identify subtle changes in anterior chamber depth (ACD) or chamber volume (CV) following PRP, which may represent a subclinical choroidal effusion. The study further attempts to determine if the degree of change of ACD and CV correlates with total PRP energy.
Subjects with type 2 diabetes with retinopathy undergoing PRP were dilated in both eyes with tropicamide 1% and phenylephrine 2.5%. After 45min, a Pentacam scan (Oculus, Germany) was performed on each eye and repeated 30 minutes after unilateral PRP. Untreated fellow eyes were used as controls. A Volk quadraspheric lens was used for all patients.
Eleven eyes of 10 patients underwent PRP (1 patient had PRP in both eyes with a 1-week interval between sessions). PRP was performed using a 532nm laser with 200μm spot size, 280-440 MW, 0.03-0.04 sec, and number of spots ranging 1122-3532. There was no significant change in ACD after PRP (mean=2.95±0.56mm before; mean=2.94±0.57mm after, p=0.23), nor in the control eyes (mean=2.91±0.60mm before; mean=2.91±0.58mm after, p=0.38). CV decreased significantly after PRP by 5.3%, (mean=163.45±29.07mm3 before; mean=154.82±34.17mm3 after, p=0.05), but did not change significantly in controls (mean=157.82±.77mm3 before; mean=158.55±31.77 mm3 after, p=0.38). Eyes with 3000 or more spots (6 of the 11 eyes), showed no significant change in ACD after PRP (mean=2.82±0.54mm before; mean=2.80±0.56mm after, p=0.21), nor in the controls (mean=2.76±0.59mm before; mean=2.76±0.55mm after, p=0.44). The CV in this subgroup decreased after PRP by 8.44%, which trended towards statistical significance (mean=163.83±34.61mm3 before; mean=150.00±41.12mm3 after, p=0.08), while there was no significant change in CV in the control eyes, (mean=157.17±34.66mm3 before; mean=160.50±37.74mm after, p=0.19).
This study detected a statistically significant decrease in CV in eyes undergoing PRP for diabetic retinopathy, which may represent a choroidal microeffusion. Eyes undergoing heavy PRP had an even greater reduction of CV, which trended toward statistical significance. This study is currently recruiting more patients to increase its power.
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