Comparative study between pointwise and ranked threshold distribution analyses of change in serial fields for short-wavelength automated perimetry.

PURPOSE: To assess the validity of ranked threshold distribution (RTD) analysis for longitudinal evaluation of short-wavelength automated perimetry (SWAP). METHODS: Eighty-five patients with glaucoma and with three or more SWAP results were examined. An additional 20 patients with glaucoma and 3 stable standard automated visual fields and 3 stable SWAP fields were assessed to calculate variability. An RTD curve was created. For RTD analysis and pointwise analysis, values that decreased more than the SWAP variability were considered to have worsened. Using pointwise analysis, four groups were defined: no change (without any 2 contiguous points decreasing in threshold); focal change (at least 2 contiguous points with decreased thresholds in either hemifield); diffuse change (more than 50% of the entire 52 locations with significant decrease in thresholds); and focal and diffuse change (less than 50%, but crossing both hemifields). RESULTS: Using pointwise analysis, 32 (37.6%) patients did not change; 23 (27.1%) patients had focal worsening; 8 (9.4%) patients had diffuse worsening; and 22 (25.9%) patients had focal and diffuse worsening. Significant differences were found among the groups in the number of deteriorating locations (P < 0.0001, analysis of variance). The ranges of deteriorating locations identified by RTD analysis for focal change and diffuse change did not overlap. A significant correlation was found between the numbers of locations with decreased threshold by both analyzes (r2 = 0.83, P < 0.0001). CONCLUSION: For evaluation of possible SWAP progression, RTD analysis is closely related with pointwise analysis and is useful for visualizing a diffuse component of change in the field.

Optic disk topography after medical treatment to reduce intraocular pressure.

PURPOSE: We examined changes in optic disk topography using confocal scanning laser ophthalmoscopy after reducing intraocular pressure with administration of latanoprost. METHODS: Twenty-nine patients with glaucoma or ocular hypertension were imaged using the Heidelberg Retina Tomograph before and after the administration of latanoprost to decrease intraocular pressure. Average time between pretreatment and posttreatment imaging was 2.7 +/- 1.8 weeks. Heidelberg Retina Tomograph software-measured parameters were mean height of contour, cup area, cup volume, mean cup depth, maximum cup depth, cup shape, rim area, rim volume, cup-to-disk ratio, and retinal nerve fiber thickness. RESULTS: Average intraocular pressure decreased significantly (mean +/- SD) by 7.2 +/- 5.4 mm Hg (25 +/- 16% decrease). No statistically significant changes in measured topographic parameters were found. When data from patients with decreases in intraocular pressure of 7 mm Hg or greater were analyzed separately (mean intraocular pressure decrease = 10.79 +/- 4.32 mm Hg, 36 +/- 8% decrease), cup area (P =.005), cup volume (P =. 002), and cup-to-disk ratio (P =.005) decreased significantly, and rim area (P =.005) increased significantly. Linear regression analysis of the data from all subjects showed that a change in intraocular pressure after latanoprost administration accounted for 12% or more of the variance in two measured topographic parameters (mean cup depth and cup shape). CONCLUSIONS: These results suggest that, in some patients, moderate decreases in intraocular pressure may affect disk topography, as measured by Heidelberg Retina Tomograph. Intraocular pressure should be considered when analyzing consecutive confocal scanning laser ophthalmoscopy images for glaucomatous progression.

Short-wavelength automated perimetry and standard perimetry in the detection of progressive optic disc cupping.

OBJECTIVE: To compare progression in short-wavelength automated perimetry (SWAP) and white-on-white (standard) perimetry in eyes with progressive glaucomatous changes of the optic disc detected by serial stereophotographs. METHODS: Forty-seven glaucoma patients with at least 2 disc stereophotographs more than 2 years apart, along with standard perimetry and SWAP examinations within 6 months of each disc photo of the same eye, were included in the study. The mean follow-up time was 4.1 years (range, 2.0-8.9 years). Baseline and follow-up stereophotographs were then graded and compared for the presence of progression. Progression in standard perimetry and SWAP, using the Advanced Glaucoma Intervention Study scoring system and a clinical scoring system, was compared between eyes with progressive change on stereophotographs and those without. RESULTS: Twenty-two of 47 eyes showed progressive change by stereophotographs. There was a statistically significant difference in the mean change in Advanced Glaucoma Intervention Study scores for both standard perimetry (P<.004) and SWAP (P<.001) between the progressed and nonprogressed groups. The sensitivity, specificity, and area under the receiver operator characteristic curve were higher using SWAP than standard perimetry when evaluated by either algorithm. This was statistically significant only in the area under the receiver operator characteristic curve for the Advanced Glaucoma Intervention Study scoring system (P =.04). CONCLUSIONS: Short-wavelength automated perimetry identified more patients than standard perimetry as having progressive glaucomatous changes of the optic disc. Compared with standard perimetry, SWAP may improve the detection of progressive glaucoma. Arch Ophthalmol. 2000;118:1231-1236

Parapapillary atrophy in patients with focal visual field loss.

PURPOSE: To examine parapapillary atrophy in normal subjects and patients with primary open-angle glaucoma with focal visual field loss. METHODS: Twenty-nine patients with repeatable early focal visual field loss according to standard automated perimetry (Humphrey program 24-2) and 29 matched (age and disk area) normal subjects were included. Parapapillary atrophy area and optic disk topography were evaluated with a confocal scanning laser ophthalmoscope. The difference in parapapillary atrophy area between normal subjects and patients with glaucoma was examined. Optic disk topography was evaluated by means of the rim-disk area ratio in 36 10-degree sectors and classified into diffuse and focal patterns of neuroretinal rim thinning. In patients with a focal pattern, the locations of rim thinning and parapapillary beta zone atrophy were compared. RESULTS: Beta zone atrophy was detected more frequently in patients with glaucoma (45% [13/29]) than in normal subjects (7% [2/29]), and it was located both superiorly and inferiorly in 92% (12/13) of the glaucoma patients. Alpha zone atrophy was significantly larger in patients with glaucoma than normal subjects (P = .009) but not more frequent (97% [28/29] in both groups). Sixty-one percent (8/13) of glaucoma patients with beta atrophy had diffuse thinning and 31% (4/13) had focal thinning. Eight percent (1/13) did not have neuroretinal rim thinning. In the four patients with both focal rim thinning and beta zone atrophy, the location of rim thinning corresponded to the location of the beta zone atrophy (100% [4/4]). CONCLUSIONS: In patients with early focal glaucomatous visual field loss, the presence and location of parapapillary beta zone atrophy and neuroretinal rim thinning are in good correspondence. Observation of localized parapapillary beta zone atrophy in clinical practice should direct one to more closely examine the optic disk in this region, as it may reveal localized rim thinning in a disk previously considered to be normal. Moreover, diffuse structural change in an eye with only focal functional change, as determined by standard automated perimetry, is consistent with the possibility that structural damage may be more widespread than functional damage in these patients.

Relationship between parapapillary atrophy and visual field abnormality in primary open-angle glaucoma.

PURPOSE: To investigate the relationship of parapapillary atrophy measured by confocal scanning laser ophthalmoscopy to visual field sensitivity measured with standard automated perimetry and short-wavelength automated perimetry in patients with primary open-angle glaucoma. METHODS: Forty-seven eyes of 47 primary open-angle glaucoma patients with increased intraocular pressure (> or = 22 mm Hg) were enrolled. Optic nerve head topography and parapapillary atrophy (beta and alpha zones) were assessed by confocal scanning laser ophthalmoscopy. Mean deviation and corrected pattern SD were assessed with standard automated perimetry and short-wavelength automated perimetry. RESULTS: Beta and alpha zones were found in 23 (49%) and 47 (100%) eyes with primary open-angle glaucoma, respectively. The area of beta zone showed significant correlations with MD of standard automated perimetry, corrected pattern SD of standard automated perimetry, and corrected pattern SD of short-wavelength automated perimetry (Spearman r = -0.366, P = .012; r = 0.327, P = .025; and r = 0.436, P = .002, respectively). The area of alpha zone showed a significant correlation with mean deviation of standard automated perimetry (r = -0.378, P = .009). Mean MD of standard automated perimetry, mean corrected pattern SD of standard automated perimetry, and mean corrected pattern SD of short-wavelength automated perimetry were significantly worse in eyes with beta zone than in eyes without beta zone. CONCLUSIONS: Parapapillary atrophy measured by confocal scanning laser ophthalmoscopy, especially beta zone, is associated with glaucomatous visual field loss demonstrated by standard automated perimetry and short-wavelength automated perimetry.

Patterns of optic disk damage in patients with early focal visual field loss.

PURPOSE: To study the patterns of structural damage of the optic disk in patients with early focal visual field loss using a confocal scanning laser ophthalmoscope. METHODS: Thirty-nine subjects with repeatable early focal visual field loss were included. The Heidelberg Retina Tomograph (Heidelberg Engineering, Heidelberg, Germany) was used to obtain topographic optic disk measurements. For analysis of structural damage, the topographic measurements were divided into 36 10-degree sectors. Sector analysis was performed using sector rim area to sector disk area ratio. Patients were assigned to one of three groups based on the measurement of the optic disk damage: (1) diffuse disk damage; (2) focal disk damage; or (3) no detectable disk damage. RESULTS: Approximately half of the patients with early focal glaucomatous visual field loss showed diffuse optic disk damage, one quarter to one third had focal damage, and one sixth had no detectable damage. Optic disk area was smallest in the no-detectable-damage group (1.71 + 0.19 mm2), followed by the focal-damage group (2.06 + 0.54 mm2), and was largest in the diffuse damage group (2.29 + 0.48 mm2; P = .22). CONCLUSION: In patients with early focal glaucomatous visual field loss, observable optic disk damage can be diffuse, focal, or undetectable. The Heidelberg Retina Tomograph may be capable of detecting different patterns of diffuse or focal structural damage.

Nerve fiber layer measurements with scanning laser polarimetry in ocular hypertension.

OBJECTIVE: To measure and compare scanning laser polarimeter measurements of the nerve fiber layer in normal subjects and in patients with ocular hypertension (OHT). METHODS: Scanning laser polarimetry was performed in 39 normal subjects and 39 age-matched patients with OHT. One eye of each patient was randomly selected for the study. For each eye, a mean retardation map was calculated from 3 separate scans of 65536 individual retinal locations (256 x 256 pixels). Retardation measurements within a 10-pixel-wide band located concentrically with the disc margin at 1.7-disc diameters were evaluated. RESULTS: Mean (+/-SD) retardation (in degrees) was significantly higher (P = .03) in normal subjects (10.4 +/- 1.5 degrees) than in patients with OHT (9.7 +/- 1.0 degrees). In the inferior retina, mean +/-SD retardation was higher (P = .03) in normal subjects (10.8 +/- 1.7 degrees) than in patients with OHT (10.1 +/- 1.0 degrees). In the superior retina, mean +/-SD retardation also was higher in normal subjects (9.8 +/- 1.6 degrees) than in patients with OHT (9.3 +/- 1.2 degrees), although the difference was not statistically significant (P = .19). Retardation measurements for 3 of eight 45 degrees sectors around the disc were significantly higher in normal subjects than in patients with OHT. CONCLUSION: Retardation measurements with the scanning laser polarimeter were significantly lower in patients with OHT than in normal subjects.