Impact of coronary artery bypass grafting surgery on the chorioretinal biomicroscopic characteristics

BACKGROUND: Most patients with cardiovascular disorders suffer from coronary artery diseases, which can be treated successfully using coronary artery bypass grafting (CABG). One of the unpleasant events following CABG is postoperative vision loss (POVL). Vulnerability of retinal vessels to hemodynamic changes, an expectable event following CABG, may contribute to the development of POVL, which might be associated with the changes in the choroidal and retinal structures. AIM: To investigate postoperative changes in chorioretinal and peripapillary nerve fiber layer (NFL) thickness, and progression of diabetic and hypertensive retinopathy after CABG. METHODS: In this prospective, cross-sectional study, 49 eyes in 25 candidates for CABG underwent both ophthalmic and cardiovascular examinations within 6 mo prior to and 9 mo after surgery. RESULTS: Among the study participants, 56% were male with a mean age of 62.84 years ± 10.49 years (range 33–80 years). Diabetes mellitus was observed in eight participants (32%). None of the patients suffered from postoperative anterior or posterior ischemic optic neuropathy, central retinal artery occlusion, and cortical blindness. The mean value of the preoperative best corrected visual acuity was 0.11 ± 0.10 logMAR (range, 0–0.4), which worsened to 0.15 ± 0.08 logMAR (range, 0–0.4) after CABG (P = 0.031). No significant difference was observed between the pre- and postsurgical choroidal (P = 0.853) and macular (P = 0.507) thickness, NFL thickness in the subfoveal (P > 0.999) and peripapillary areas (P = 0.659), as well as the severity of diabetic and hypertensive retinopathy. CONCLUSION: CABG may reduce visual acuity without affecting ocular structures. Postoperative vision reduction might be attributable to molecular or cellular variations, changes in visual pathway function, or central nervous system.