Comparison of Macular Choroidal Thickness in Treatment-Naive Normal-Tension Glaucoma and Ocular Hypertension Patients

Introduction:To evaluate foveal, temporal parafoveal, and nasal parafoveal choroidal thicknesses together with retinal nerve fiber layer (RNFL) parameters in treatment-naive patients with normal-tension glaucoma (NTG), and to compare these findings with those of patients with ocular hypertension (OHT).Methods: This retrospective cross-sectional study included one eye from each of 40 NTG patients and 66 OHT patients.In all participants, quadrant-and clock-hour-based RNFL measurements and foveal, temporal-parafoveal, and nasal-parafoveal choroidal thicknesses were assessed using optical coherence tomography.Results: No significant differences were observed between the groups regarding age, sex, axial length, or disc area.Mean RNFL thickness and quadrant-based and clock-hour RNFL values were significantly lower in the NTG group than in the OHT group at all locations except the 9 o'clock sector (p<0.05).While no significant intergroup differences were detected in foveal or nasal parafoveal choroidal thickness, temporal parafoveal choroidal thickness was greater in the OHT group than in the NTG group (p=0.047). Conclusion:Based on the present results, macular choroidal thickness by itself does not appear to provide sufficient discriminatory value in normal-tension glaucoma.Rather than relying solely on macular choroidal measurements, microvascular changes in the optic nerve head may represent a more relevant contributor to glaucomatous damage.Future investigations integrating functional vascular imaging modalities may clarify the mechanisms underlying the pathophysiology of normal-tension glaucoma.