VA indicated sharpness or clarity of vision. BCVA assessed by early treatment diabetic retinopathy study chart using 4 meter (m), 1m distance, or if participant was able to count fingers, perceive hand motion or light. At 4m (>= 20 letters), VA score=number of letters correct plus 30 (credited for 30 letters at 1m); otherwise , VA score=number of letters read correctly at 1m plus number read at 4m (if any). If no letters were read correctly at 4m or 1m, VA score= 0, which were excluded from summary statistics calculation. BVCA score ranged: 0 (poor eyesight) to 78 (best eyesight).