Quantifying the Effects of Macular Pucker Vitrectomy Surgery on Macular Structure and Function

Abstract

Purpose: : To study the effects of macular pucker surgery by comparing pre- and post-operative macular structure, evaluated by combined Optical Coherence Tomography-Scanning Laser Ophthalmoscopy (OCT-SLO), and macular function, assessed by 3-D computer-automated threshold Amsler grid (3D-CTAG) testing.

Methods: : 10 subjects with macular pucker were tested pre- and post-operatively at 0-2, 2-6, and 6-12 weeks and compared to 27 normal controls. OCT-SLO indices of macular structure were: Central Foveal Thickness, Central Circle Thickness, Central Circle Volume, Total Average Thickness, and Total Macular Volume. 3D-CTAG indices were: Visual Field Area, Lost Area Grade (LAG) = (scotoma area at highest contrast level/scotoma area at lowest contrast level) x scotoma depth [%], Horizontal Slope, and Total Slope. Vitrectomy with membrane peeling was performed (JS) with 25 gauge instruments and sutureless technique.

Results: : All preoperative OCT-SLO indices and 3D-CTAG LAG and slopes were significantly elevated compared to controls (P<0.0001 for each parameter). An increase in visual acuity was noted at post-op weeks 2-6 (43.8%; p=0.02) and weeks 6-12 (61.1%; p=0.008). At post-op weeks 2-6, LAG, horizontal slope, and total slope improved by 49.4% (p=0.02), 47.7% (p=0.03), and 49.1% (p=0.04), respectively. By post-op weeks 6-12, none of these indices were different from the normal controls (p=0.1 for each parameter). OCT-SLO detected a decrease in central foveal thickness, central circle thickness, and central circle volume at post-op weeks 2-6 by 27% (p=0.03), 22.5% (p=0.04), and 22.8% (p=0.04), respectively.

Conclusions: : OCT-SLO detected improvements in central macular structure within 2-6 weeks after macular pucker surgery. There were corresponding improvements in central macular function as evaluated by concurrent 3D-CTAG. This new method of evaluating macular function may thus be useful in assessing pre-operative status and improvement following macular pucker surgery or other forms of therapy.

Keywords: macula/fovea • imaging/image analysis: clinical • vitreoretinal surgery