Incidence of central involving macular oedema after cataract surgery in diabetic retinopathy patients – A prospective study

Abstract

Aim: To study the incidence of central macular oedema at 4, 8 and 12 weeks following cataract surgery in diabetic retinopathy eyes. Materials and Methods: A prospective observational study was conducted over a period of 3 months to investigate the presence of centrally involved macular oedema following cataract surgery in diabetic retinopathy patients. Preoperative OCT scans were performed and patients without centrally involved macular oedema were enrolled. Subfield thickness (central, outer and inner) was measured preoperatively and at 4, 8 and 12 weeks postoperatively. The correlation between diabetic macular oedema (DME) and HbA1c, as well as random blood sugar (RBS) levels at the time of surgery, was analysed. Best-corrected visual acuity (BCVA) was assessed preoperatively and postoperatively, and fundus examinations were conducted each visit to evaluate diabetic retinopathy progression. Results: This study included 80 eyes from 44 patients. Postoperatively, central subfield thickness (CSF) increased significantly at first (14.7 μm), second (26.7 μm) and third (30.3 μm) compared to baseline. Inner subfield thickness (ISF) also increased at first (13.3 μm), second (20.6 μm) and third (24.3 μm) months, while the outer subfield thickness (OSF) showed progression from 6.7 μm to 16.6 μm from the first to third month. A statistically significant shift in DME was observed three months post-cataract surgery. There was a significant association between HbA1c levels and the development of DME, but no correlation with RBS levels. BCVA improved remarkably from preoperative mean log MAR of 0.75 to a mean log MAR of 0.1 at 3 months postoperatively. About 30% had mild non-proliferative diabetic retinopathy (NPDR) preoperatively, and in that group, 60% progressed to moderate NPDR. The status of moderate and severe NPDR remained the same postoperatively at 3 months. Of all patients who progressed to moderate NPDR, 3 cases developed non-central macular oedema, and three cases developed both central and non-central macular oedema postoperatively at 3 months. All eyes with severe NPDR resulted in DME, except for one (9.1%) eye. Conclusion: Preoperatively, 57.5% had no macular oedema, while 42.5% had non-central macular oedema. Postoperatively, 4.4% had central oedema, and 10.9% had both central and non-central oedema among those who initially had no macular oedema. Additionally, 38.2% developed oedema in both central and non-central regions among patients initially presenting with non-central macular oedema. There was also a significant statistical difference with longer duration of diabetes mellitus, severity of diabetic retinopathy and elevated HbA1c values with the development of diabetic macular oedema postoperatively. However, larger sample sizes and longer-term follow-up are essential for assessing retinopathy progression and the incidence of DME.

Keywords

• central macular oedema
• central subfield thickness
• diabetic retinopathy