To study correlation of HbA1c and macular thickness changes in diabetic patients after phacoemulsification and small incision cataract surgery (SICS)

Abstract

To study the relationship between HbA1c and macular thickness using Optical coherence tomography (OCT) in phacoemulsification and SICS. Retrospective study where 100 eyes of type 2 Diabetes mellitus patients with mild to moderate Non-Proliferative Diabetic Retinopathy (NPDR) were included. 50 PATIENTS underwent uncomplicated phacoemulsification surgery AND REST 50 FOR SICS and were divided into 3 groups based on HbA1c levels – Group 1: <6.5%, Group 2: 6.5%–8% and group 3: >8%. Nine macular subfields as defined by Early Treatment of Diabetic Retinopathy study (ETDRS) were measured using OCT. The HbA1c level of each patient was measured and compared with the macular thickness as well as visual acuity. The macular thickness was found to be significantly higher postoperatively in SICS group (251.54 ± 22.69 μm) than the PHACO group (230.44 ± 26.47 μm) on post-operative day 7 and it further increased to (267.46 ± 43.44 μm) in SICS group as compared to phaco group (244.50 ± 37.30 μm)on postoperative 1 month in group C. CMT was highest if HbA1C levels were more than 8% as compared to other two groups on all post-operative day.No significant difference was found in BCVA between both the groups on 1 month and 3 months post-operatively. This study shows that cataract surgery increases the macular thickness and these increases are significantly higher in the SICS than in PHACO eyes on the POD 7, 1 month and 3 months after surgery, especially if HbA1c levels are more than 6.5%, which resolves to near normal levels in phaco group by POD 3 months. This indicates that phacoemulsification is more preferable surgery then SICS in adults with regard to postoperative increase in macular thickness. Also good control of HbA1c levels significantly decreases post-operative visual problems.