Postoperative Visual Acuity Outcomes After Phacoemulsification in Patients With Type 2 Diabetes Mellitus: A Systematic Review

Cataract surgery is commonly performed in people with type 2 diabetes mellitus (T2DM), but concerns persist regarding postoperative visual recovery even before the onset of diabetic retinopathy. Understanding outcomes in this population is essential for evidence-based counselling and perioperative management. Our objective in this systematic review was to evaluate postoperative visual acuity outcomes following phacoemulsification in adults with T2DM without diabetic retinopathy or diabetic macular oedema, compared with non-diabetic individuals. A systematic search of Web of Science, Scopus, and PubMed was conducted in May 2025, from database inception. Eligible studies included English-language prospective comparative studies reporting postoperative visual acuity outcomes following phacoemulsification in T2DM patients without pre-existing proliferative diabetic retinopathy or macular disease, compared with non-diabetic controls. Study selection, data extraction, and risk-of-bias assessment using the Newcastle-Ottawa Scale were performed independently and in duplicate. Of 121 records screened, 11 full texts were assessed, and two studies met the inclusion criteria. The two included prospective comparative cohort studies involved 137 eyes in patients with T2DM and 137 eyes in non-diabetic controls. Both studies demonstrated substantial postoperative improvement in best-corrected visual acuity in both groups. Subclinical postoperative corneal and macular changes were more frequent in diabetics in one study, without a meaningful impact on functional vision over the reported follow-up. Risk of bias was moderate in both studies due to residual confounding and short-term follow-up. In conclusion, patients with T2DM without retinopathy experience excellent post-operative visual outcomes after phacoemulsification, comparable to those of non-diabetic individuals. Vigilant perioperative monitoring remains warranted due to increased susceptibility to transient corneal and retinal changes. High-quality studies with longer follow-up and appropriate adjustment for diabetic severity are required to refine prognostic accuracy and confirm long-term outcome equivalence.