Background: Diabetes mellitus (DM) affects over 240 million people globally, with ocular complications like dry eye disease (DED) being particularly prevalent. DED impacts the quality of life significantly, affecting 52.8% of DM patients compared to 9.3% of healthy individuals. This study aims to evaluate and compare the severity and pattern of DED post-phacoemulsification cataract surgery among non-diabetic patients, diabetics without diabetic retinopathy, and diabetics with diabetic retinopathy and/or macular edema. Methods: this cross-sectional study done at Benha University Hospital, 45 patients were divided into three groups (15 each): non-diabetic, diabetic without retinopathy, and diabetic with retinopathy and or macular edema. Comprehensive ocular examinations, including Tear Film Break-Up Time (TBUT), Schirmer I test (SIT), Ocular Surface Disease Index (OSDI), Tear Meniscus Height (TMH), corneal staining, and corneal epithelial thickness by anteing OCT were conducted. Results: The mean age was 54.3 ± 6.6 years. Statistically significant differences were found across groups for TBUT (P = .003), SIT (P = .022), OSDI (P = .001), and TMH (P = .031). Specifically, diabetics with retinopathy exhibited the most severe DED, with OSDI scores averaging 45.6 ± 9.4 (P < .001). Corneal staining was significantly higher in diabetic patients (P = .004).Superior corneal epithelial thickness was significantly thinner in diabetic patients (P = .025). Conclusion: Post-phacoemulsification cataract surgery, DED incidence is significantly higher in diabetic patients, particularly those with retinopathy and/or macular edema. These findings underscore the need for vigilant monitoring and management of DED in diabetic patients undergoing cataract surgery.