Clinical Predictors of the Region of First Structural Progression in Early Normal-tension Glaucoma

Purpose: This study aimed to compare the clinical characteristics of patients who showed structural progression in the peripapillaryretinal nerve fiber layer (RNFL) first against those who showed progression in the macular ganglion cell-inner plexiformlayer (GCIPL) first and to investigate clinical parameters that help determine whether a patient exhibits RNFL or GCIPLdamage first. Methods: A retrospective review of medical records of patients diagnosed with early-stage normal-tension glaucoma wasperformed. All eyes underwent intraocular pressure measurement with Goldmann applanation tonometer, standard automatedperimetry, and Cirrus optical coherence tomography at 6-month intervals. Structural progression was determinedusing the Guided Progression Analysis software. Blood pressure was measured at each visit. Results: Forty-one eyes of 41 patients (mean age, 52.6 ± 16.7 years) were included in the study. In 21 eyes, structural progressionwas first detected in the RNFL at 54.2 ± 14.8 months, while structural progression was first observed at the macularGCIPL at 40.5 ± 11.0 months in 20 eyes. The mean intraocular pressure following treatment was 13.1 ± 1.8 mmHg for theRNFL progression first group and 13.4 ± 1.8 mmHg for the GCIPL progression first group (p = 0.514). The GCIPL progressionfirst group was older (p = 0.008) and had thinner RNFL at baseline (p = 0.001). The logistic regression analyses indicated thatboth age and follow-up duration until first progression predicted the region of structural progression (odds ratio, 1.051; 95%confidence interval, 1.001-1.105; p = 0.046 for age; odds ratio, 0.912; 95% confidence interval, 0.840-0.991; p = 0.029 fortime until progression). Conclusions: Age of glaucoma patients and time until progression are associated with the region of the first structural progressionin normal-tension glaucoma. Further studies exploring the association between glaucomatous progression and thelocation of damage are needed.