Methods: A cross-sectional study was conducted involving 114 Malay patients with POAG seen at the eye clinic of Hospital Universiti Sains Malaysia. Patients aged between 40 and 80 years who were diagnosed with other types of glaucoma, previous glaucoma filtering surgery or other surgeries except uncomplicated cataract surgery and pterygium surgery were excluded. A total of 101 patients who were followed up for dry eyes, age-related cataracts or post cataracts extraction surgery were recruited as control subjects. Those with family history of glaucoma or glaucoma suspect were excluded. Microvascular endothelial function was assessed using laser Doppler fluximetry and the process of iontophoresis. Iontophoresis with acetylcholine (ACh) and sodium nitroprusside (SNP) was used to measure microvascular endothelium-dependent and endothelium-independent vasodilatations, respectively.
Results: In general, POAG patients demonstrated lower ACh% and AChmax values compared with controls. There was significant difference in microvascular endothelial function [ACh%: mean, 95% confidence interval = 503.1 (378.0, 628.3), and AChmax: mean, 95% confidence interval = 36.8 (30.2, 43.5)] between primary open angle glaucoma cases (p
METHODS: Diurnal variation of intraocular pressure was measured in 202 eyes of suspected open-angle glaucoma patients and 100 control eyes, at 4-hourly intervals for 24 hours (phasing). Based on the phasing results, optic disc changes and visual field defects, the patients were diagnosed as primary open angle glaucoma (POAG), normal tension glaucoma (NTG), ocular hypertension (OHT), or physiologic cup (PC), or still remained as glaucoma suspects due to inconclusive diagnosis. The last group (glaucoma suspects) was then followed up 6-monthly for their eventual outcome.
RESULTS: The highest percentage of suspected glaucoma patients had peak (maximum) readings in the mid-morning (10-11 A.M.) and trough (minimum) readings after midnight (2-3 A.M.); the highest percentage of control group had peak readings in the late evening (6-7 P.M.) and trough readings after midnight (2-3 A.M.). The mean amplitude of variance was 6 mm Hg in suspected glaucoma group and 4 mm Hg in the control group. After 'phasing', 18.8% of the suspected glaucoma patients were diagnosed as POAG, 16.8% as NTG, 5% as OHT, and 28.7% as physiologic cup; 30.9% remained as glaucoma suspects. After 4 years follow-up, 70% of the glaucoma suspects still remained as glaucoma suspects, 6.7% developed NTG and another 6.7% POAG; 16.6% were normal.
CONCLUSIONS: Serial measurement of IOP ( phasing) in a 24-hour period is still needed, in order not to miss the peak and the trough IOP readings in suspected open-angle glaucoma patients, which helps in better management of glaucoma. Among 30.9% of patients who remained as glaucoma suspects after the initial phasing, 13.4% developed NTG/POAG over a period of 4 years.
METHODS: 1H-MRS utilising the Single-Voxel Spectroscopy (SVS) technique was performed using a 3.0Tesla MRI on 45 optic radiations (15 from healthy subjects, 15 from mild glaucoma patients, and 15 from severe glaucoma patients). A standardised Volume of Interest (VOI) of 20 × 20 × 20 mm was placed in the region of optic radiation. Mild and severe glaucoma patients were categorised based on the Hodapp-Parrish-Anderson (HPA) classification. Mean and multiple group comparisons for metabolite concentration and metabolite concentration ratio between glaucoma grades and healthy subjects were obtained using one-way ANOVA.
RESULTS: The metabolite concentration and metabolite concentration ratio between the optic radiations of glaucoma patients and healthy subjects did not demonstrate any significant difference (p > 0.05).
CONCLUSION: Our findings show no significant alteration of metabolite concentration associated with neurodegeneration that could be measured by single-voxel 1H-MRS in optic radiation among glaucoma patients.
KEY POINTS: • Glaucoma disease has a neurodegenerative component. • Metabolite changes have been observed in the neurodegenerative process in the brain. • Using SVS, no metabolite changes in optic radiation were attributed to glaucoma.
OBJECTIVE: To determine whether retinal nerve fiber layer (RNFL) measurement can be used to detect glaucoma in uveitic eyes with elevated intraocular pressure (IOP).
DESIGN, SETTING, AND PARTICIPANTS: Comparative case series of RNFL measurement using optical coherence tomography performed from May 1, 2010, through October 31, 2012, at a tertiary referral center. We assigned 536 eyes with uveitis (309 patients) in the following groups: normal contralateral eyes with unilateral uveitis (n = 72), normotensive uveitis (Uv-N) (n = 143), raised IOP and normal optic disc and/or visual field (Uv-H) (n = 233), and raised IOP and glaucomatous disc and/or visual field (Uv-G) (n = 88).
EXPOSURES: Eyes with uveitis and elevated IOP (>21 mm Hg) on at least 2 occasions.
MAIN OUTCOMES AND MEASURES: Comparison of RNFL values between groups of eyes and correlation with clinical data; risk factors for raised IOP, glaucoma, and RNFL thinning.
RESULTS: Mean (SD) global RNFL was thicker in Uv-N (106.4 [21.4] µm) compared with control (96.0 [9.0] µm; P glaucoma and RNFL defect.
CONCLUSIONS AND RELEVANCE: Screening for glaucomatous RNFL changes in uveitis must be performed during quiescent periods. Thinning of the inferior quadrant suggests that glaucomatous damage, more than uveitic ocular hypertension, is in fact occurring. Measurement of RNFL may detect signs of damage before disc or visual field changes and therefore identifies a subgroup that should receive more aggressive treatment.
METHOD: A meta-analysis was conducted to determine the potential impact of isometric exercise on IOP and OPP. The literature on the relationship between isometric resistance exercise and IOP was systematically searched according to the "Cochrane Handbook" in the databases of Pubmed, Web of Science, EBSCO, and Scopus through December 31, 2020. The search terms used were "exercise," "train," "isometric," "intraocular pressure," and "ocular perfusion pressure," and the mean differences of the data were analyzed using the Stata 16.0 software, with a 95% confidence interval.
RESULTS: A total of 13 studies, which included 268 adult participants consisting of 162 men and 106 women, were selected. All the exercise programs that were included were isometric resistance exercises of the lower limbs with intervention times of 1min, 2min, or 6min. The increase in IOP after intervention was as follows: I2=87.1%, P=0.001 using random-effects model combined statistics, SMD=1.03 (0.48, 1.59), and the increase in OPP was as follows: I2=94.5%, P=0.001 using random-effects model combined statistics, SMD=2.94 (1.65, 4.22), with both results showing high heterogeneity.
CONCLUSION: As isometric exercise may cause an increase in IOP and OPP, therefore, people with glaucoma and related high risk should perform isometric exercise with caution.
METHODS: We measured psychophysical contrast thresholds in one eye of 16 control subjects and 19 patients aged 67.8 ± 5.65 and 71.9 ± 7.15, respectively, (mean ± SD). Patients ranged in disease severity from suspects to severe glaucoma. We used the 17-region FDT-perimeter C20-threshold program and a custom 9-region test (R9) with similar visual field coverage. The R9 stimuli scaled their spatial frequencies with eccentricity and were modulated at lower temporal frequencies than C20 and thus did not display a clear spatial frequency-doubling (FD) appearance. Based on the overlapping areas of the stimuli, we transformed the C20 results to 9 measures for direct comparison with R9. We also compared mfVEP-based and psychophysical contrast thresholds in 26 younger (26.6 ± 7.3 y, mean ± SD) and 20 older normal control subjects (66.5 ± 7.3 y) control subjects using the R9 stimuli.
RESULTS: The best intraclass correlations between R9/C20 thresholds were for the central and outer regions: 0.82 ± 0.05 (mean ± SD, p ≤ 0.0001). The areas under receiver operator characteristic plots for C20 and R9 were as high as 0.99 ± 0.012 (mean ± SE). Canonical correlation analysis (CCA) showed significant correlation (r = 0.638, p = 0.029) with 1 dimension of the C20 and R9 data, suggesting that the lower and higher temporal frequency tests probed the same neural mechanism(s). Low signal quality made the contrast-threshold mfVEPs non-viable. The resulting mfVEP thresholds were limited by noise to artificially high contrasts, which unlike the psychophysical versions, were not correlated with age.
CONCLUSION: The lower temporal frequency R9 stimuli had similar diagnostic power to the FDT-C20 stimuli. CCA indicated the both stimuli drove similar neural mechanisms, possibly suggesting no advantage of FD stimuli for mfVEPs. Given that the contrast-threshold mfVEPs were non-viable, we used the present and published results to make recommendations for future mfVEP tests.