Cataract Surgery Increases Macular, Choroidal Thickness in Patients with Diabetic Retinopathy

In patients with early diabetic retinopathy without diabetic macular edema (DME), uncomplicated phacoemulsification resulted in greater increases in retinal superficial capillary plexus vascular density (SCP-VD), macular thickness (MT), and choroidal thickness (CT) when compared with controls, according to a study published in Frontiers in Medicine.¹

Patients with diabetes mellitus are 5 times more likely to develop cataracts, a leading cause of blindness globally, compared to those without diabetes. Phacoemulsification is a common, safe, and effective surgery for the treatment of cataract. However, previous research reported the surgery was a risk factor for macular edema and secondary progression in this patient population.²

“It has also been suggested that these complications may not be a direct effect of surgery but rather a natural course of disease progression; therefore, it is clinically meaningful to determine the possible impact of cataract surgery on the occurrence of DME and/or the progression of diabetic retinopathy,” wrote a group of investigators from the Department of Ophthalmology at Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, China.

The prospective study enrolled 22 patients with cataract and mild to moderate nonproliferative diabetic retinopathy (NPDR; 13 males and 9 females) and 22 controls (12 males and 10 females) to assess changes in macular status and CT post-surgery. SCP-VD, MT, and CT were measured prior to surgery and postoperatively using optical coherence tomography (OCT). Patients received complete ophthalmologic examinations, including best-corrected visual acuity (BCVA), slit-lamp examination, intraocular pressure (IOP), axial length (AL), and dilated fundal examinations.

The IOP at 1 week, 1 month, and 3 months postoperatively was lower compared with baseline measurements in both cohorts. Additionally, BCVA increased in both groups at 3 months post-surgery (P = .615).

In the diabetic retinopathy cohort, patients saw significant increases in parafoveal SCP-VD between 1 week and 1 month post-surgery (P <.001). The SCP-VD at months 1 and 3 postoperatively demonstrated changes in parafovea were significantly greater in patients with diabetic retinopathy when compared with the control group. The controls saw no significant differences in SCP-VD between any time points postoperatively. There were no significant differences in foveal SCP-VD at baseline, 1 week, 1 month, and 3 months post-surgery in the diabetic retinopathy cohort.

Significant increases in MT and CT were observed in the fovea and perifovea at all postoperative visits in patients with diabetic retinopathy. Changes in parafoveal MT were significantly greater in patients than controls at all post-surgery visits. Additionally, changes in MT and CT in the fovea were significantly greater in the diabetic retinopathy cohort than controls at months 1 and 3 postoperative.

Investigators noted the small sample size as a limitation, although patients were homogeneous regarding ethnicity, sex, and retinopathy, which reduced certain confounding effects. The short follow-up period further limited the findings; therefore, longer-term follow-up is needed to assess the duration of the increases in MT and CT after phacoemulsification as well as the progression of diabetic retinopathy severity and incidence of DME.

An ANCOVA test did not show a link between variations in SCP-VD and cumulative dissipated energy (CDE) in either group. After adjusting for CDE, the parafoveal SCP-VD increased significantly at months 1 and 3 in patients with diabetic retinopathy.

“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,” investigators concluded.

References

1. ^{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 (Lausanne). 2023;10:1290599. Published 2023 Nov 14. doi:10.3389/fmed.2023.1290599}
2. ^{Menchini, U, Cappelli, S, and Virgili, G. Cataract surgery and diabetic retinopathy. Semin Ophthalmol. (2003) 18:103–8. doi: 10.1076/soph.18.3.103.29805}