Cataract surgery doubles risk of retinopathy in patients with diabetes, study finds
August 17, 2009
According to the results of a recent Australian study, patients with diabetes who are at risk of diabetic retinopathy (DR) experience a two-fold increase in the risk of developing DR or experiencing a progression of their retinopathy within one year of phacoemulsification ("phaco") cataract surgery.
But the news is not all bad: Phaco cataract surgery causes less progression of DR than older cataract surgery techniques.
Cataract surgery and diabetic retinopathy: Study design and methods
Subjects in the study were diabetic patients age 65 and older who had cataract surgery at an eye clinic in Sydney, Australia between 2004 and 2006.
Assessment of diabetic retinopathy was performed via digital retinal photography prior to cataract surgery and at one, six and 12 months after surgery.
Odds ratios — a measure of the strength of association between two things — were calculated for DR development and/or progression in eyes having cataract surgery compared with eyes not undergoing surgery. Odds ratios were adjusted for age, sex, diabetes duration and preoperative blood glucose levels.
Cataract surgery was performed using a modern phacoemulsification procedure, where the cataractous lens is broken into small pieces with an ultrasound probe and these pieces are removed from the eye with a surgical vacuum tube. A foldable intraocular lens (IOL) is then inserted into the eye through the same small incision used to remove the cataract.
Cataract surgery and diabetic retinopathy: Study results
Analysis of the study data revealed:
- During the 12-month post-operative period, among eyes without pre-existing diabetic retinopathy, 28.2 percent of eyes undergoing cataract surgery developed diabetic retinopathy, compared with 13.8 percent of eyes that did not undergo the procedure (adjusted odds ratio: 2.65).
- In a paired-eye comparison (comparing the two eyes of the same patient, with one eye undergoing cataract surgery and the other eye not undergoing the procedure), in eyes at risk of DR progression, 35.6 percent of eyes that had surgery exhibited progression of diabetic retinopathy, compared with 20 percent of fellow eyes that did not undergo the procedure (adjusted odds ratio: 2.21).
Cataract surgery and diabetic retinopathy: Conclusions
Based on the results of the study, the researchers concluded that diabetic patients undergoing phacoemulsification cataract surgery appear to have a doubling of the risk of developing diabetic retinopathy or experiencing a progression of DR within one year of surgery.
These results, however, suggest phacoemulsification cataract surgery poses less risk of diabetic retinopathy progression than older cataract surgery techniques (intracapsular cataract surgery and extracapsular cataract surgery, the researchers said.