Abstract
Purpose::
To determine preoperative indicators of postoperative diabetic macular edema, at 6 months, in patients undergoing phacoemulsification and intraocular lens implantation.
Methods::
Patients with diabetes mellitus (DM; type II insulin dependent and non insulin dependent) and controls (age-matched patients without diabetes mellitus) undergoing cataract extraction were consented to have serum and aqueous samples of vascular endothelial growth factor (VEGF) and serum levels of insulin-like growth factor-1 (IGF-1) taken at the time of cataract surgery. All patients had full ophthalmologic examinations, visual acuity testing using the ETDRS chart (VA); and ocular coherence tomography (OCT) measurements of foveal thickness (FT), central macular thickness (CMT), and macular volume (MV). VEGF and IGF-1 levels were determined using enzyme linked immunosorbent assay (ELISA). Outcomes determined postoperatively (one month and 6 months) include VA, CMT, FT, and MV. A linear discriminant analysis was performed to predict postoperative CMT at 1 month and 6 months and FT at 1 month and 6 months using preoperative predictors.
Results::
One month results have been reported previously. 39 patients (n=20 DM; 19 control) had been enrolled and completed 6 month followup. The median postoperative FT at 6 months (197 micrometers) was used to create two groups: normal postoperative FT (less than or equal to 197 micrometers) and high postoperative FT (greater than 197 micrometers). The linear discriminant model correctly predicted 86% of patients as to postoperative FT when a reduced set was used (preoperative CMT and serum IGF-1).
Conclusions::
We previously reported on the value of a reduced set of variables (presence of diabetes, preoperative CMT, and serum VEGF) in predicting increased postoperative CMT at 1 month. Data at 6 months show similar predictive value in predicting increased FT at 6 months, using a different set of variables (preoperative CMT and serum IGF-1). Aqueous VEGF appeared to play no predictive role at 1 month or 6 months. While an informed decision rule using a reduced set of variables achieved a high prediction rate of patients with macular edema, biologic variability in growth factor expression may limit the value of these tests as predictors. However, preoperative CMT was predictive of postoperative macular edema at both time points supporting the importance of treating macular edema prior to cataract surgery.
Keywords: edema • macula/fovea • diabetic retinopathy