The Incidence of Cystoid Macular Odema in Diabetic and Non-Diabetic Patients After Uneventful Phacoemulsification Cataract Surgery

Purpose: To study the Comparison of difference from baseline in central macular thickness and appearance of intra-retinal cystoid spaces between diabetic and non-diabetic patients undergoing uncomplicated phacoemulsification. Study design: A Prospective observational non-interventional comparative study. Methods: In this study 64 eyes were assessed by optical coherence tomography preoperatively and postoperatively day 1, week 1, week 4 and 12 week after uncomplicated phacoemulsification with endocapsular foldable intraocular lens (IOL) implantation under peribulbar anesthesia. The study included 32 eyes of non-diabetic patients (Group 1) and 32 eyes of diabetic patients (Group 2). The preoperative and post operative changes in central macular(sub-field) thickness (CMT), macular cube volume thickness (MCV), average macular cube thickness (AMT) and development of cystoid macular edema on OCT of each group were noted and compared. Results: In group 1(non –diabetics) the preoperative mean central macular (sub-field) thickness (CMT) was 249.38 ± 19.64 µm and group 2 (non-diabetics) it was 257.66 ± 23.65 µm respectively. Post operatively central macular (sub-field) thickness [CMT] at 1 week in diabetic patients was significantly higher than in non-diabetic patients. The percent change in central macular thickness at 1 week in group 1 (non –diabetics) and group 2 (diabetic)was 6% with mean 264.53± 30.29 and 13 % with mean 295.81± 80.53. The differences between each group were statistically significant at 1week. the preoperative mean macular cube thickness (MCV) in group 1 was 9.44. ± 0.38 mm3 and group 2 it was 9.67± 0.55 mm3. In our study the macular cube volume [CV] in group 1 and group 2, was 1.6% with mean 9.60±0.44 mm3 and 3% mean 9.94±0.81 mm3, the difference between two groups was statistically significant. In group 1 the preoperative mean average macular cube volume (AMT) was 267.94 ±12.70 and in group 2 it was 274.34±13.92. The difference between two groups was not statistically significant up to 12 weeks. In group 1 mean BCVA preoperatively was 0.40 ±0.16 and in group 2 it was 0.43± 0.14. In our study percentage change in the BCVA between group 1 and group 2 (estimated using LOGMAR visual acuity chart) at 1week and 4 week was statistically significant. However, this difference was no longer statistically significant at 12 weeks. At 1 week and 4 weeks % change in BCVA in group 1 was 91% with mean 0.03 ±0.09 and 93.98% with mean 0.02±0.10 and in group 2 it was 77.37% with mean 0.11±0.17 and 91.26% with mean 0.10±0.15 respectively. Conclusion: Diabetic patients are a challenge to the ophthalmologists as they are more likely to develop macular edema after cataract surgery than non-diabetic patients. It is the most important cause for uneventful visual outcome after surgery. Early detection of macular edema helps in prevention and treatment. Pre-operative OCT testing provides a baseline for post-operative comparison. This strategy helps the clinician in early detection of increase in macular thickness and cystoid macular edema. This study has demonstrated change in central macular thickness, change in macular cube thickness, change in average macular cube thickness, and appearance of cystoid macular edema in both non –diabetic and diabetic patients. The incidence of substantial increase in macular thickness was associated with impaired visual acuity. This study has demonstrated that the increase in the macular thickness and macular edema is more prominent in diabetic eyes than non-diabetic eye at 1 week after surgery. The patients having more increased of central macular thickness and presence cystoid macular edema may need more aggressive treatment than other patient for example intravitreal steroids. OCT is noninvasive and has good reproducibility and thus helps in monitoring the anatomical changes of the retina in the postoperative period. Owing to its high sensitivity, OCT is suitable to demonstrate the postoperative subtle changes of the macular thickness and subclinical macular edema