Comparitive Study of Optical Coherence Tomographic Analysis of Macula in Preoperative And Postoperative Diabetic Patients Undergoing Small Incision Cataract Surgery.

Abstract

BACKGROUND Diabetic Macular Edema (DME) is the Micro vascular complication of diabetes which leads to loss of vision. The underlying pathogenesis is disruption of inner blood retinal barrier which leads to fluid and lipid accumulation in the central part of retina. Which is seen clinically as increase in thickness of macular area with hard exudate formation. Diabetic patients pose a great challenge when there is diabetic retinopathy along with cataract which causes severe visual morbidity. So the risk of developing vision loss also depends upon the grade of diabetic retinopathy (mild, moderate, severe) after cataract surgery. After surgical insult there is prostaglandin release and its association with preexisting diabetic retinopathy which might be the cause of macular edema after cataract surgery. The relative increase in thickness of macula which is difficult to detect clinically. OCT which a noninvasive modality particularly useful in measuring the macular thickness. Hence this study is undertaken to measure the macular thickness in diabetic patients who are undergoing cataract surgery using macular analysis protocols scans on Cirrus HD OCT. AIM AND OBJECTIVE OF THE STUDY To compare and analyze pre-operative and post-operative OCT changes in macula of diabetic patients undergoing cataract surgery. Methods: This was a hospital based prospective comparative study conducted from October 2018 to April 2020. Study participants are 65 diabetic patients undergoing cataract surgery. Each eye underwent fundus examination with indirect DocuSign Envelope ID: FD3981479E12BDB5--52035A25--44E29283--B8F1DD0--42E83D889482BDE1C418EB5 XV ophthalmoscopy with 20D lens before surgery. If any changes are seen fundus photography is taken. Optical coherence tomography testing was performed before surgery i.e. preoperatively and at postoperatively at day 1, 1 week, 4 weeks and at 12 weeks. Best-corrected visual acuity (BCVA) was recorded at each visit. Results: Out of 65 Patients, 59 patients (90.7%) completed the 3 months follow-up 59 patients (90.7%) completed the 3 months follow-up. mean age of the study population was 66.0 ±7.8years. 36 patients (61%) were males and 23 (39%) were males. Mean Age duration of DM is 4.8±2.9 yrs. No Diabetic retinopathy was in 26 patients.18 patients had Mild NPDR. 8 patients had Moderate NPDR. 4 patients had moderate NPDR with ME, Severe NPDR with macular edema in 1 patient and pre op macular edema is seen in 2 patients. By Postoperative 3 months 89.8% patients achieved a visual acuity of 6/6 – 6/12. The central subfield macular thickness increased in all patients irrespective of presence or absence of diabetic retinopathy of about 17.4±25.3μm and 29μm±38.8 at 1 month and 3 month follow up. Eyes with no diabetic retinopathy developed thickening of 15.2±μm and 21.2μm, the group with mild NPDR had increase in foveal thickness of 4.4±4μm and 8.4±4.4um, the group with moderate non proliferative diabetic retinopathy with macular edema had largest increase in foveal thickness of about 57.5±36.7um and 135±68.4μm at 4th & 12th week after surgery respectively. This increase in foveal thickness was correlated inversely with VA improvement in pre-op macular edema patients Conclusions: There was a statistically significant increase seen in CSMT after cataract surgery especially in patients with preoperatively diagnosed macular edema. Associated retinopathy also acts as a risk factor. But there was no statistically significant increase in mild and moderate NPDR preoperatively and also in postoperative period after uncomplicated small incision cataract surgery In patients with no DR Macular thickness changes are Subclinical. We implicate that influence of cataract surgery and the release of inflammatory mediators cause blood retinal barrier breakdown that could affect the thickness measurements.