Eye Changes After Cataract Surgery Associated With Diabetic Retinopathy

Greater increases in retinal superficial capillary plexus vascular density (SCP-VD), macular thickness (MT), and choroidal thickness (CT) occurred in patients with early diabetic retinopathy (DR) without preoperative diabetic macular edema (DME) compared with controls when they underwent uncomplicated phacoemulsification surgery for cataracts, according to a study published in Frontiers in Medicine.

Individuals with diabetes have been known to be 5 times more likely to develop cataracts,which can lead to blindness, compared with those without diabetes. Cataract surgery can be a risk factor for postoperative macular edema and secondary progression, however. This study aimed to assess the effect of cataract surgery on the macular microvasculature as well as MT and CT in patients with DR vs controls.

Female eye with long eyelashes close-up | Image credit: Vladimir Voronin - stock.adobe.com

All patients included in this study had ophthalmologic examinations before participating in the study. This exam included best-corrected visual acuity (BCVA), intraocular pressure (IOP), and axial length (AL). For patients who had surgery in both eyes, the eye that was first operated on was used in the study. Patients were recruited from October 2020 to October 2022 from the Ophthalmology Department of Ruijin Hospital in Shanghai, China. Patients were included if they were 40 years or older, had a spherical diopter of less than –6 D, had an axial length of less than 26 mm, and had no history of intraocular surgery, DME and DR treatment, or glaucoma.

An optical coherence tomography (OCT) B-scan was done for all patients. Values for MT, CT, and SCP-VD were all provided automatically. All patients had phacoemulsification procedure with no complications.

There were 44 eyes from 44 participants who were included in the study, of which 22 were control eyes; the nonproliferative DR (NPDR) group had 13 men and 9 women, whereas the control group had 12 men and 10 women. Differences in age, sex, BCVA, IOP, and AL were not significant. In the NPDR group, 3 patients who had mild NPDR and 19 had moderate NPDR. All participants had an improvement in BCVA after surgery.

The DR group had no significant difference in foveal SCP-VD after operation but instead had an increase parafoveal SCP-VD at 1 and 3 months after the surgery compared with baseline, which was not found in the control group (mean [SD] fovea difference at 3 months, –0.17 [1.68%] vs 0.09 [2.3%]; mean [SD]parafovea difference at 3 months, 2.05 [1.35%] vs 0.77 [1.82%]). There was no significant difference in SCP-VD at any other time point.

The MT for patients in the DR group increased in all subfields at all 3 visits after surgery at 1 week, 1 month, and 3 months compared with the baseline. MT, measured in μm, had a significant change by the third month post operation compared with baseline in the fovea (34.86 [17.68] vs 17.23 [13.15]), the parafovea (22.55 [13.95] vs 11.69 [12.87]), and the perifovea (20.38 [16.81] vs 6.75 [6.21]).

CT increased at 1 week, 1 month, and 3 months after operation in the DR group for the fovea and 1 month and 3 months forthe parafovea. The changes in CT in μm were greater for the DR group at 3 months after surgery for the fovea (16.63 [13.38] vs 6.93 [15.29]) and the parafovea (15.34 [14.71] vs 6.51 [13.54]).

There were some limitations to this study. The sample size was small, although participants had varying degrees of retinopathy, ethnicity, and sex. The long-term effects on retina vessels could not be evaluated with the shorter follow-up period. The authors noted that a longer follow-up period would allow for assessment of the duration during which MT and CT would continue to increase as well as how that would affect the progression of DR.

The researchers concluded that uncomplicated phacoemulsification appeared to increase MT, SCP-VD, and CT for patients who had not had a prior surgery for DME and had mild or moderate NPDR compared with controls.

“However, the short-term postoperative visual prognosis of cataract patients with mild to moderate NPDR without preoperative DME is the same as that of healthy patients in this study,” the authors wrote.

Reference

Yao H, Yang Z, Cheng Y, Shen X. Macular changes following cataract surgery in eyes with early diabetic retinopathy: an OCT and OCT angiography study. Front Med. Published online November 14, 2023. doi:10.3389/fmed.2023.1290599