Comparison of Matrix with Humphrey Field Analyzer II with SITA.

PURPOSE: To study the performance of the Matrix perimeter compared with the Humphrey Field Analyzer II (HFA) with the Swedish Interactive Thresholding Algorithm over the range of contrast sensitivities each machine could estimate. METHODS: Fifty stable glaucoma subjects at various stages of disease and three normal subjects had visual fields testing done on five different days within 8 weeks with both perimeters. Intraclass correlation coefficient of mean deviation, pattern standard deviation, and the SD of repeat measurements were evaluated. The repeatability of the sensitivity estimates at individual locations and global indices was quantified, as well as their dependence on disease severity. The relationship between sensitivity determinations with the two instruments was explored (principal curve analysis). RESULTS: Mean deviation on the HFA ranged from -31 to +2.5 dB. The mean deviation and pattern standard deviation had intraclass correlation coefficients above 0.90 for both instruments. Over most of the useful range (above 20 dB on the HFA), a difference of 1 dB for the Matrix corresponded to a difference of 2 dB for the HFA. The SD of repeat measurements increased with disease severity with HFA, but not with Matrix, except that values of 12 or 34 dB were highly variable on repeat. Variability was reduced for both HFA and Matrix when duplicate sensitivity values were used. A single Matrix test provided only 15 possible sensitivity values, unevenly spaced, but the average of duplicate measurements provided more numerous sensitivity values. A learning effect was detected for Matrix. CONCLUSIONS: The decibel values reported by the two machines are not equivalent. Variability of sensitivity determinations is affected more by the sensitivity level with HFA than with Matrix. Duplicate measurements for baseline and follow-up evaluation could be important, especially for Matrix. Further information on learning effects is needed, as is commercially available progression software for Matrix.

Progression of patterns (POP): a machine classifier algorithm to identify glaucoma progression in visual fields.

PURPOSE: We evaluated Progression of Patterns (POP) for its ability to identify progression of glaucomatous visual field (VF) defects. METHODS: POP uses variational Bayesian independent component mixture model (VIM), a machine learning classifier (MLC) developed previously. VIM separated Swedish Interactive Thresholding Algorithm (SITA) VFs from a set of 2,085 normal and glaucomatous eyes into nine axes (VF patterns): seven glaucomatous. Stable glaucoma was simulated in a second set of 55 patient eyes with five VFs each, collected within four weeks. A third set of 628 eyes with 4,186 VFs (mean ± SD of 6.7 ± 1.7 VFs over 4.0 ± 1.4 years) was tested for progression. Tested eyes were placed into suspect and glaucoma categories at baseline, based on VFs and disk stereoscopic photographs; a subset of eyes had stereophotographic evidence of progressive glaucomatous optic neuropathy (PGON). Each sequence of fields was projected along seven VIM glaucoma axes. Linear regression (LR) slopes generated from projections onto each axis yielded a degree of confidence (DOC) that there was progression. At 95% specificity, progression cutoffs were established for POP, visual field index (VFI), and mean deviation (MD). Guided progression analysis (GPA) was also compared. RESULTS: POP identified a statistically similar number of eyes (P > 0.05) as progressing compared with VFI, MD, and GPA in suspects (3.8%, 2.7%, 5.6%, and 2.9%, respectively), and more eyes than GPA (P = 0.01) in glaucoma (16.0%, 15.3%, 12.0%, and 7.3%, respectively), and more eyes than GPA (P = 0.05) in PGON eyes (26.3%, 23.7%, 27.6%, and 14.5%, respectively). CONCLUSIONS: POP, with its display of DOC of progression and its identification of progressing VF defect pattern, adds to the information available to the clinician for detecting VF progression.

Estimating the rate of retinal ganglion cell loss in glaucoma.

PURPOSE: To present and evaluate a new method of estimating rates of retinal ganglion cell (RGC) loss in glaucoma by combining structural and functional measurements. DESIGN: Observational cohort study. METHODS: The study included 213 eyes of 213 glaucoma patients followed up for an average of 4.5 ± 0.8 years with standard automated perimetry visual fields and optical coherence tomography. A control group of 33 eyes of 33 glaucoma patients underwent repeated tests over a short period to test the specificity of the method. An additional group of 52 eyes from 52 healthy subjects followed up for an average of 4.0 ± 0.7 years was used to estimate age-related losses of RGCs. Estimates of RGC counts were obtained from standard automated perimetry and optical coherence tomography, and a weighted average was used to obtain a final estimate of the number of RGCs for each eye. The rate of RGC loss was calculated for each eye using linear regression. Progression was defined by a statistically significant slope faster than the age-expected loss of RGCs. RESULTS: From the 213 eyes, 47 (22.1%) showed rates of RGC loss that were faster than the age-expected decline. A larger proportion of glaucomatous eyes showed progression based on rates of RGC loss rather than based on isolated parameters from standard automated perimetry (8.5%) or optical coherence tomography (14.6%; P < .01), while maintaining similar specificities in the stable group. CONCLUSIONS: The rate of RGC loss estimated from combining structure and function performed better than either isolated structural or functional measures for detecting progressive glaucomatous damage.

Quantifying discordance between structure and function measurements in the clinical assessment of glaucoma.

OBJECTIVE: To evaluate a new method of quantifying and visualizing discordance between structural and functional measurements in glaucomatous eyes by predicting the visual field (VF) from retinal nerve fiber layer thickness (RNFLT) using a bayesian radial basis function. METHODS: Five GDx VCC RNFLT scans and 5 Humphrey 24-2 Swedish Interactive Thresholding Algorithm VF tests were performed for 50 glaucomatous eyes from 50 patients. A best-available estimate (BAE) of the true VF was calculated as the pointwise median of these 5 replications. This BAE VF was compared with every RNFLT-predicted VF from the bayesian radial basis function and every measured VF. Predictability of VFs from RNFLT was established from previous data. A structure-function pattern discordance map and a structure-function discordance index (scores of 0-1) were established from the predictability limits for each structure-function measurement pair to quantify and visualize the discordance between the structure-predicted and measured VFs. RESULTS: The mean absolute difference between the structure-predicted and BAE VFs was 3.9 dB. The mean absolute difference between measured and BAE VFs was 2.6 dB. The mean (SD) structure-function discordance index score was 0.34 (0.11). Ninety-seven (39%) of the structure-predicted VFs showed significant discordance (structure-function discordance index score >0.3) from measured VFs. CONCLUSIONS: On average, the bayesian radial basis function predicts the BAE VF from RNFLT slightly less well than a measured VF from the 5 VFs composing the BAE VF. The pattern discordance map highlights locations with structure-function discordance, with the structure-function discordance index providing a summary index. These tools may help clinicians trust the mutually confirmatory structure-function measurements with good concordance or identify unreliable ones with poor concordance.

Reproducibility of peripapillary retinal nerve fiber thickness measurements with stratus OCT in glaucomatous eyes.

PURPOSE: To determine the reproducibility of Stratus OCT peripapillary retinal nerve fiber layer (RNFL) measurements in glaucomatous eyes. DESIGN: Experimental study. PARTICIPANTS: Fifty-one stable glaucoma patients with a range of severity. METHODS: Peripapillary RNFL thickness was measured using the Standard and Fast scan protocols of Stratus optical coherence tomography (OCT) 3 times on the same day to determine intrasession variability and on 5 different days within a 2-month period to determine intersession variability. The same instrument was used by the same operator for all scans. MAIN OUTCOME MEASURES: Intraclass correlation coefficient (ICC), coefficient of variation (COV), and test-retest variability. RESULTS: For mean RNFL thickness, the intrasession and intersession ICCs for the Standard and Fast scans were 0.98 and 0.96, respectively. The COV ranged from 3.8% to 5.2%. Test-retest variability was approximately 7 microm between sessions, most of which can be attributed to the approximate 5-microm variability within each session. For quadrants, the ICC was 0.9 or higher and the COV was under 10% except nasally. Test-retest variability for quadrant measurements ranged from 6 to 16 microm. For clock hours, test-retest variability approached 20 microm between sessions in some sectors. In general, the ICC was lower in the nasal region than elsewhere. Variability was greater the smaller the area over which RNFL thickness was determined. Intrasession variability was not a predictor of intersession variability in individual subjects (P Standard = 0.72, P Fast = 0.28). There was no relationship between variability and mean RNFL thickness (P Standard = 0.28, P Fast = 0.93). CONCLUSIONS: The reproducibility of Stratus OCT for RNFL thickness is sufficiently good to be useful clinically as a measure of glaucoma progression. When comparing 2 mean RNFL values on different days in the same eye, an 8-microm decrease in thickness might be accepted as within normal limits of test-retest variability with 95% tolerance. For quadrants and clock-hour sectors, variability is higher, and more detailed calculations are necessary.

Reproducibility of pattern electroretinogram in glaucoma patients with a range of severity of disease with the new glaucoma paradigm.

PURPOSE: To determine the reproducibility of the pattern electroretinogram with the new Pattern Electroretinogram for Glaucoma (PERGLA) recording paradigm in glaucoma patients with a range of severity. DESIGN: Experimental study. PARTICIPANTS: Fifty-three glaucoma patients were recruited for the study (mean age +/- standard deviation [SD], 69+/-11 years). Their mean deviation (MD) global indices on static automatic perimetry ranged from 2.16 to -31.36 decibels (mean MD, -9.05). INTERVENTION: All patients had pattern electroretinogram recordings done 5 times by the same operator, on 5 different days with the standardized PERGLA paradigm. MAIN OUTCOME MEASURES: Pattern electroretinogram amplitude (microvolts), phase (pi radians), response variability (coefficient of variation [CV] = SD/mean x 100) of amplitude and phase of 2 partial averages that build up the pattern electroretinogram waveform, interocular asymmetry in amplitude and phase (in terms of the CV generated by the pattern electroretinogram software), signal-to-noise (S/N) ratio, SDs, CV, and intraclass correlation coefficient (ICC). All analyses were done on one eye of each subject, except when interocular asymmetry was studied. RESULTS: The CVs of intrasession variabilities in amplitude and phase were 12.08% and 2.20%, respectively, and those of intersession variabilities were 20.82% and 4.17%. The pattern electroretinogram produced intersession ICCs in amplitude and phase of 0.791 and 0.765, respectively. These ICCs were significantly higher than the ICCs for pattern electroretinogram interocular asymmetry in amplitude and phase (0.659 [P<0.05] and 0.571 [P<0.05], respectively). On average, the pattern electroretinogram S/N ratio in glaucomatous patients was about 5:1. CONCLUSIONS: The reproducibility of PERGLA in glaucomatous patients is sufficiently good for it to be considered a useful complementary clinical tool. Being more reproducible, direct measures of amplitude and phase should be more useful in monitoring progression than interocular asymmetry comparisons.

Ophthalmological and biological features of the oculorespiratory syndrome after influenza vaccination.

We report the ophthalmological and laboratory findings of 6 patients who, after influenza vaccination, were affected by oculorespiratory syndrome (ORS), complaining of red eyes, photophobia, blurred vision, palpebral edema, ocular pain and itching, and conjunctival secretions. The conjunctivae were mildly hyperemic with few follicles, but the ophthalmological examination findings were otherwise normal. Patients had lymphopenia and decreased levels of the total hemolytic complement and the third and fourth component of the complement. We conclude that ORS causes conjunctivitis and seems to involve the complement.