Purpose: To demonstrate differences in optic nerve head (ONH), retinal nerve fiber layer (RNFL), and macular thickness in patients with internal carotid artery (ICA) stenosis using spectral domain optical coherence tomography (SD-OCT).
Methods: A case-controlled study was conducted in 31 patients with a diagnosis of unilateral ICA stenosis (the percentage of stenosis was between 65 and 85%), and 53 age- and sex-matched healthy subjects (control group) from March 2016 to April 2018. The ONH parameters, RNFL, and macular thicknesses in the nine macular quadrants according to the Early Treatment Diabetic Retinopathy Study (ETDRS) were measured using SD-OCT.
Results: The average macular thickness and outer macular quadrants measurements were lower in the ICA stenosis group (P < 0.05). The thickness of the fovea and inner macular quadrants was similar in healthy and patient eyes. Similarly, the ONH and RNFL profiles based on SD-OCT parameters were similar between the groups. There was a negative weak correlation between mean macular and RNFL thicknesses and the duration and percentage of ICA stenosis.
Conclusion: The average macular thickness and measurements of outer macular quadrants in the ICA stenosis group were lower than in the control group. Macular changes may occur before symptomatic ocular ischemic syndrome (OIS). SD-OCT macular measurements may be beneficial in the early detection of OIS due to ICA stenosis.
Keywords: Internal carotid artery stenosis; Macula; Optical coherence tomography; RNFL.