Abstract
This study investigated the predicted risk factors for the development of normal-tension glaucoma (NTG) in NTG suspects. A total of 684 eyes of 379 NTG suspects who were followed-up for at least 5 years were included in the study. NTG suspects were those having (1) intraocular pressure within normal range, (2) suspicious optic disc (neuroretinal rim thinning) or enlarged cup-to-disc ratio (≥ 0.6), but without definite localized retinal nerve fiber layer (RNFL) defects on red-free disc/fundus photographs, and (3) normal visual field (VF). Demographic, systemic, and ocular characteristics were determined at the time of the first visit via detailed history-taking and examination of past medical records. Various ocular parameters were assess using spectral-domain optical coherence tomography and Heidelberg retinal tomography. Conversion to NTG was defined either by the presence of a new localized RNFL defect at the superotemporal or inferotemporal region on disc/fundus red-free photographs, or presence of a glaucomatous VF defect on pattern standard deviation plots on two consecutive tests. Hazard ratios were calculated with the Cox proportional hazard model. In total, 86 (12.6%) of the 684 NTG suspects converted to NTG during the follow-up period of 69.39 ± 7.77 months. Significant (P < 0.05, Cox regression) risk factors included medication for systemic hypertension, longer axial length, worse baseline VF parameters, thinner baseline peripapillary RNFL, greater disc torsion, and lamina cribrosa (LC) thickness < 180.5 μm (using a cut-off value obtained by regression analysis). Significant (P < 0.05, Cox regression) risk factors in the non-myopic NTG suspects included medication for systemic hypertension and a LC thinner than the cut-off value. Significant (P < 0.05, Cox regression) risk factors in the myopic NTG suspects included greater disc torsion. The results indicated that 12.6% of NTG suspects converted to NTG during the 5–6-year follow-up period. NTG suspects taking medication for systemic hypertension, disc torsion of the optic disc in the inferotemporal direction, and thinner LC of the optic nerve head at baseline were at greater risk of NTG conversion. Related baseline risk factors were different between myopic and non-myopic NTG suspects.
Highlights
This study investigated the predicted risk factors for the development of normal-tension glaucoma (NTG) in NTG suspects
The optic nerve head (ONH) measurements showed excellent reproducibility, with intraclass correlation coefficients (ICC) for ONH measurements of 0.985 for prelaminar thickness, 0.974 for lamina cribrosa (LC) depth-BMO (Bruch’s membrane opening), 0.982 for LC depth-peripapillary sclera (PPS), and 0.952 for LC thickness
Subjects with eyes that converted to NTG were significantly older (P = 0.019), had a higher frequency of family history of glaucoma (P = 0.027), were more likely to be taking medication for systemic hypertension (P < 0.001), and had eyes with a longer axial length (P = 0.031) than those who did not convert to NTG
Summary
This study investigated the predicted risk factors for the development of normal-tension glaucoma (NTG) in NTG suspects. Glaucoma suspects are defined as individuals with clinical findings or risk factors that may increase the likelihood of developing glaucoma, including high intraocular pressure (IOP), suspicious appearance of the optic disc or the retinal nerve fiber layer (RNFL), and occludable or narrow angles in the anterior chamber. The rate of developing glaucomatous visual field (VF) damage in individuals with suspicious optic disc or RNFL, but with normal VF and IOP within the normal range (mostly classified as normotensive preperimetric glaucoma), was reported to range from 13% to 57.7% after a 3–5-year follow-up period[4,5,6,7,8] This suggests wide variation in the likelihood of developing glaucoma according to the possessed risk factors. Analysis was performed to find out risk factors for NTG development in NTG suspect according to the presence of myopia
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
