Detection of retinal glial cell activation in glaucoma by time domain optical coherence tomography.

BACKGROUND: Activated retinal astrocytes and Müller cells (ARAM) have been found in glaucoma patients. This study investigated whether presumed ARAM can be detected by optical coherence tomography (OCT), and assessed their relationship to the retinal nerve fiber layer (RNFL) thickness. PATIENTS AND METHODS: Single-center observational study involving 35 age-matched healthy controls and 19 patients with primary open-angle glaucoma (POAG) between 45 - 82 years of age. Presumed ARAM was defined as patchy, discrete glittering but transparent changes of the macula. The retina was documented by red-free photography to assess distribution of ARAM, and compared to the RNFL thickness measured around the fovea by OCT. A linear mixed effects model was used to detect a difference between eyes with ARAM versus eyes without ARAM. RESULTS: ARAM was not found in healthy subjects. The mean RNFL around the fovea was not significantly thicker in healthy controls (34.01 SD ± 22.24) than in POAG patients with ARAM (30.86 microns SD ± 15.09; p = 0.36) or without ARAM (33.19 microns SD ± 19.87; p = 0.46). Furthermore, the median RNFL thickness was similar to the control group (29 microns) but slightly thinner in POAG patients (each 27 microns with ARAM and without ARAM). In a subgroup analysis of POAG patients with ARAM, the within subject standard deviation of RNFL was significantly lower in areas with ARAM (SD 10.12) than in areas without ARAM (SD 17.30) (p < 0.001). CONCLUSIONS: Although the mean and median RNFL thickness was comparable between the groups, the variability of the RNFL thickness was significantly lower in areas with ARAM than in areas without ARAM suggesting that ARAM may mask RNFL loss in POAG patients.

Clinical evaluation of a novel population-based regression analysis for detecting glaucomatous visual field progression.

BACKGROUND: The distinction of real progression from test variability in visual field (VF) series may be based on clinical judgment, on trend analysis based on follow-up of test parameters over time, or on identification of a significant change related to the mean of baseline exams (event analysis). The aim of this study was to compare a new population-based method (Octopus field analysis, OFA) with classic regression analyses and clinical judgment for detecting glaucomatous VF changes. PATIENTS AND METHODS: 240 VF series of 240 patients with at least 9 consecutive examinations available were included into this study. They were independently classified by two experienced investigators. The results of such a classification served as a reference for comparison for the following statistical tests: (a) t-test global, (b) r-test global, (c) regression analysis of 10 VF clusters and (d) point-wise linear regression analysis. RESULTS: 32.5 % of the VF series were classified as progressive by the investigators. The sensitivity and specificity were 89.7 % and 92.0 % for r-test, and 73.1 % and 93.8 % for the t-test, respectively. In the point-wise linear regression analysis, the specificity was comparable (89.5 % versus 92 %), but the sensitivity was clearly lower than in the r-test (22.4 % versus 89.7 %) at a significance level of p = 0.01. A regression analysis for the 10 VF clusters showed a markedly higher sensitivity for the r-test (37.7 %) than the t-test (14.1 %) at a similar specificity (88.3 % versus 93.8 %) for a significant trend (p = 0.005). In regard to the cluster distribution, the paracentral clusters and the superior nasal hemifield progressed most frequently. CONCLUSIONS: The population-based regression analysis seems to be superior to the trend analysis in detecting VF progression in glaucoma, and may eliminate the drawbacks of the event analysis. Further, it may assist the clinician in the evaluation of VF series and may allow better visualization of the correlation between function and structure owing to VF clusters.

Quality of diurnal intraocular pressure control in primary open-angle patients treated with latanoprost compared with surgically treated glaucoma patients: a prospective trial.

PURPOSE: To compare the intraocular pressure (IOP) diurnal fluctuations of glaucoma patients treated with latanoprost 0.005% once a day with patients with controlled IOP after deep sclerectomy or trabeculectomy. METHODS: The trial included 60 prospectively recruited subjects with primary open-angle glaucoma. The medical group consisted of 20 patients with controlled IOP (<18 mm Hg) under latanoprost 0.005% monotherapy and with no history of previous intraocular surgery or argon laser trabeculoplasty; the surgical groups included 20 patients after trabeculectomy, and 20 patients after deep sclerectomy with collagen implant (DSCI). The patients in the surgical groups had a controlled IOP without any ocular hypotensive medications. All patients underwent a diurnal tension curve (08:00-17:00/three-hour intervals), followed by a water-drinking test (WDT) with the last IOP measurement taken at 21:00 hours. The between-group differences were tested for significance by means of analysis of variance (ANOVA). RESULTS: Baseline IOP was significantly different between the trabeculectomy group (10.1 mm Hg (3.4 SD)), the DSCI group (13.9 mm Hg (2.8)) and the latanoprost group (15.5 mm Hg (2.0); p = 0.005). The average IOP during the diurnal tension curve (10.1, 13.7, and 15.7 mm Hg, respectively, for the trabeculectomy, DSCI, and latanoprost groups) differed significantly between groups (ANOVA; p<0.0001), but the variation was comparable in the three groups (ANOVA; p = 0.13). After the WDT, elevation of IOP was significantly greater among patients treated with latanoprost (p = 0.003). CONCLUSION: Trabeculectomy patients had a statistically significant lower average IOP in the diurnal tension curve compared with the other two groups. No wider variation in diurnal IOP with latanoprost compared with the surgical procedures was found. The IOP increase during the WDT was most marked in patients under latanoprost therapy.