METHODS: A prospective study was carried out on 32 healthy subjects (control group) and 60 diabetic patients. The diabetic patients were divided into 2 groups. Group 1 comprised of 30 patients without diabetic retinopathy (DR) and group 2 had 30 patients with mild non-proliferative DR. A full-threshold microperimetry of the central 10° of retina (the macula) was performed on all subjects, utilizing 32 points with the MP-1. The relationship between light sensitivity and HbA1c value was calculated using linear regression analysis.
RESULTS: Total mean sensitivity at 10° for group 1 without DR, group 2 with mild NPDR and control group were 18.67±0.83, 17.98±1.42 and 19.45±0.34 (dB), respectively. There was a significant difference in total mean retinal sensitivity at 10° between the 3 groups (F(2,89)=18.14, p=0.001). A simple linear regression was calculated to predict HbA1c based on retinal sensitivity. A significant regression equation was found (F(1,90)=107.61, p=0.0001, with an R2 of 0.545). The linear regression analysis revealed that there was a 0.64dB decline in mean retinal sensitivity within the central 10° diameter with an increase of 1mmHg of HbA1c.
CONCLUSION: Retinal sensitivity at the central 10° of the macula is affected by changes in HbA1c values.
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.
DESIGN: A combined cross-sectional and prospective study on PAC and PACG.
METHODS: A total of 35 eyes were included in the study for each group of normal control, PAC, and PACG patients from eye clinics in Kota Bharu, state of Kelantan, Malaysia, from January 2007 to November 2009. The PAC and PACG patients were divided into thin and thick CCT groups. They were followed up for 12 to 18 months for visual field progression assessment with their mean Advanced Glaucoma Intervention Study (AGIS) score.
RESULTS: The CCT was 516.8 ± 26.0 µm for PAC and 509.7 ± 27.4 µm for PACG. Both were significantly thinner compared with the control group with CCT of 540 ± 27.8 µm (P < 0.001). There was a statistically significant increase in the mean AGIS score after 12.9 ± 1.7 months of follow-up in the thin CCT group for PACG (P = 0.002). However, no significant increase in the mean AGIS score was found for the thick CCT group in PACG and for both thin and thick CCT in PAC.
CONCLUSIONS: The PAC and PACG had statistically significant thinner CCT compared with the controls. Thin CCT was associated with visual field progression based on the mean AGIS score in PACG.
PURPOSE: The purpose of this study was to investigate the clinical characteristics, including 24-hour ocular perfusion pressure and risk of progression in patients with baseline central VF defect, as compared with those with peripheral VF defect in NTG.
DESIGN: This was a prospective, longitudinal study.
METHODS: A total of 65 NTG patients who completed 5 years of follow-up were included in this study. All the enrolled patients underwent baseline 24-hour intraocular pressure and blood pressure monitoring via 2-hourly measurements in their habitual position and had ≥5 reliable VF tests during the 5-year follow-up. Patients were assigned to two groups on the basis of VF defect locations at baseline, the central 10 degrees, and the peripheral 10- to 24-degree area. Modified Anderson criteria were used to assess global VF progression over 5 years. Kaplan-Meier analyses were used to compare the elapsed time of confirmed VF progression in the two groups. Hazard ratios for the association between clinical risk factors and VF progression were obtained by using Cox proportional hazards models.
RESULTS: There were no significant differences between the patients with baseline central and peripheral VF defects in terms of demography, clinical, ocular and systemic hemodynamic factors. Eyes with baseline defects involving the central fields progressed faster (difference: βcentral=-0.78 dB/y, 95% confidence interval=-0.22 to -1.33, P=0.007) and have 3.56 times higher hazard of progressing (95% confidence interval=1.17-10.82, P=0.025) than those with only peripheral defects.
CONCLUSION: NTG patients with baseline central VF involvement are at increased risk of progression compared with those with peripheral VF defect.