OBJECTIVE: To correlate glycemic control, as expressed by HbA1c levels, to the change in macular thickness in diabetic patients who undergo phacoemulsification.

METHODS: This was a prospective cohort study done at the Cataract and Medical Retina Clinics of the University of the Philippines Department of Ophthalmology and Visual Sciences (UP-DOVS), Sentro Oftalmologico Jose Rizal (SOJR) of the Philippine General Hospital, University of the Philippines - Manila. Participants included 15 diabetic patients with mature cataracts that warranted lens extraction surgery via phacoemulsification by a senior resident of the UP-DOVS. Participants were screened using pre-determined inclusion and exclusion criteria. Pre-operative best corrected visual acuity (BCVA) was obtained for both eyes using the Early Treatment Diabetic Retinopathy Study (ETDRS) chart. Pre-operative central macular thickness (CMT) was measured using the Cirrus Ocular Coherence Tomography (OCT) machine. Patients then underwent monocular phacoemulsification by their respective surgeons and instilled antibiotic and steroid drops as instructed. One month after surgery, BCVA and post-operative CMTwere measured. Blood was extracted and sent for determination of glycosylated hemoglobin (HbA1c) levels. Ttest was done to compare the mean CMT and BCVA at baseline and at 1 month after phacoemulsification in the study and control eyes. T-test was also used to compare the mean change in CMT in the study and control eyes. Simple correlation between HbA1c and CMT, as well as CMT and BCVA, was done using Pearson's R.

RESULTS: Neither mean baseline nor mean post-operative CMT between study and control eyes were statistically different  and p=0.1562). There was a statistically significant greater mean CMT in the study eye group (p=0.004). There was a mean change in CMT of 16.7 ± 18.5 ?m, and 1.8 ± 8.8 ?m in the group of control eyes (p=0.011). Mean HbA1c was 8.19%. No positive correlation was established between HbA1c and mean CMT in both study eyes (r=-0.312) and control eyes (r=-0.289). No correlation was established between BCVA and CMT (r=0.426).

CONCLUSION: In diabetics, eyes that undergo phacoemulsification gain a significant change in CMT but this may not necessarily result in macular edema and may not parallel the severity of diabetic retinopathy. We were not able to demonstrate correlation between CMT and HbA1c levels or CMT and BCVA.