Improving event-based progression analysis in glaucomatous visual fields.

Glaucoma is a progressive optic neuropathy with characteristic changes to the optic nerve head and the visual field (VF). Detecting progression of VF damage with Standard Automated Perimetry (SAP) is of paramount importance for clinical care. One common approach to detecting progression is to compare each new VF test to a baseline SAP test (event analysis). This comparison is made difficult by the test-retest variability of SAP, which increases with the level of VF damage, and the limited range of measurement, meaning that damage cannot be assessed below a certain level. We performed a prospective international multi-centre data collection of SAP data on 90 eyes from 90 people with glaucoma and different levels of VF damage over a short period of time (6 tests in 60 days). Data were collected using a fundus tracked perimeter (Compass, CenterVue). We used these data (minus the first test) to develop an improved event analysis that accounts for both the change in variability with damage and the lower bound on the measurement imposed by SAP. Using simulations, we show that our approach is more sensitive compared to previously developed methods, especially in the case of advanced glaucoma, while retaining similar specificity.

Progression of visual field in patients with primary open-angle glaucoma - ProgF study 1.

PURPOSE: To evaluate the visual field rate of progression of patients with treated ocular hypertension (OHT) and primary open-angle glaucoma (POAG) in clinical practice, using the mean deviation (MD) and the visual field index (VFI). METHODS: Non-interventional cohort study. From a large multicentre database representative of the French population, 441 eyes of 228 patients with treated OHT or POAG followed up at least 6 years with Humphrey 24.2 Sita-Standard visual field examination at least twice a year were identified. From initial data, eyes were classified in five groups: 121 with OHT, 188 with early glaucoma (MD greater than -6 dB), 45 with moderate glaucoma (MD -6 to -12 dB), 41 with advanced glaucoma (MD -12 to -18 dB) and 46 with severe glaucoma (MD less than -18 dB). Rate of progression during the follow-up period was calculated using the trend analysis of the Guided Progression Analysis software. RESULTS: The mean duration of follow-up was 8.4 ± 2.7 years and the mean number of visual field, 18.4 ± 3.5. In eyes with OHT, rate of progression was -0.09 dB/year (-0.17%VFI/year). In eyes with POAG, rate of progression was -0.32 dB/year (-0.83%VFI/year) in eyes with early glaucoma, -0.52 dB/year (-1.81%VFI/year) in moderate glaucoma, -0.54 dB/year (-2.35%VFI/year) in advanced glaucoma and -0.45 dB/year (-1.97%VFI/year) in severe glaucoma. In eyes with POAG, a significant progression (p < 0.05) was detected in 159 of 320 eyes (49.7%) with trend analysis and 117 of 320 eyes (36.6%, likely progression) or 183 of 320 eyes (57.2%, possible and likely progression) with event analysis. CONCLUSIONS: Primary open-angle glaucoma is a progressive disease in the majority of patients despite cautioned treatment and follow-up. The rate of progression varies greatly among subjects.

Reproducibility of macular ganglion cell-inner plexiform layer thickness measurement with cirrus HD-OCT in normal, hypertensive and glaucomatous eyes.

AIM: To evaluate the intraobserver and interobserver reproducibility of macular retinal ganglion cell-inner plexiform layer (GC-IPL) thickness measurement by automated detection on Optical Coherence Tomography (OCT) images in normal, hypertensive (ocular hypertensive (OHT)) and glaucomatous eyes. METHODS: A total of 138 eyes were enrolled in three groups: 69 normal, 35 OHT and 34 primary open-angle glaucoma eyes. All patients underwent a complete ocular examination, 24-2 automated perimetry, biometry and pachymetry. Macular imaging was performed in each eye using the Cirrus HD-OCT 4000 with software V.6.0. (Carl Zeiss Meditec, Dublin, California, USA) three times on the same day by each of two observers, and the GC analysis (GCA) algorithm provided parameters expressed as average, minimum and six sectoral GC-IPL thicknesses. Reproducibility was assessed by intraclass correlation coefficient (ICC), coefficient of variation (CV) and test-retest variability (TRTV) calculated as 1.96 times the SD. RESULTS: Mean GC-IPL thickness was 82.27 ± 7.37 µm, 76.84 ± 7.01 µm and 66.16 ± 11.16 µm in normal, OHT and glaucoma groups, respectively. GC-IPL thickness was significantly lower in glaucomatous eyes than in normal and OHT eyes (p<0.0001 for all parameters). In all groups, ICC ranged from 96.4 to 99.9% and 92.5 to 99.8%, CV ranged from 0.41 to 2.24% and 0.55 to 1.67%, and TRTV ranged from 0.61 to 2.64 µm and 0.83 to 2.22 µm for intraobserver and interobserver reproducibility, respectively. CONCLUSIONS: To the best of our knowledge, this is the first study of GCA algorithm reproducibility in normal, OHT and glaucomatous eyes. The reproducibility of GC-IPL thickness measurements using the Cirrus HD-OCT GCA algorithm was found to be highly satisfactory. GC-IPL thickness may be a promising new OCT parameter for analysis of ganglion cell damage in glaucoma.