The ability of short-wavelength automated perimetry to predict conversion to glaucoma.

PURPOSE: Short-wavelength automated perimetry (SWAP) has been claimed to predict conversion to glaucoma 3 to 4 years before standard automated perimetry (SAP) defects occur. This study compared the moment of glaucomatous conversion between SWAP and SAP. DESIGN: Prospective, longitudinal follow-up study. PARTICIPANTS: Four hundred sixteen subjects with ocular hypertension (intraocular pressure >/=22 and

The prevalence of glaucomatous defects with short-wavelength automated perimetry in patients with elevated intraocular pressures.

PURPOSE: To determine the prevalence of abnormal short-wavelength automated perimetry (SWAP) visual fields in subjects with elevated intraocular pressures (IOP) for 7 existing definitions of mild glaucomatous loss, and to explore the agreement between them. PATIENTS AND METHODS: Seven hundred and forty-four eyes of 379 subjects with an IOP > or = 22 and < or = 32 mm Hg and normal visual fields with standard automated perimetry (SAP) were tested with SWAP on 3 separate occasions, of which the second and third visual field were used for analysis. The appearance of the optic disc was not an eligibility criterion. We determined the number of visual fields classified as abnormal on 2 successive occasions by 7 existing definitions. In addition, we explored the agreement between the various definitions. RESULTS: The proportion of eyes with a glaucomatous visual field with SWAP ranged between 0% and 9.9%, depending on the criterion used to define abnormality. A pairwise comparison of the various definitions showed that several definitions classified different eyes as having an abnormal field. CONCLUSIONS: We found a large variation in the proportion of visual fields with SWAP classified as abnormal by the various definitions. More importantly, various definitions identified different individuals to have an abnormal field with SWAP. Therefore, the diagnostic accuracy and clinical significance of all definitions must be determined before SWAP is used in routine clinical care.

Long-term outcome in high-risk corneal transplantation and the influence of HLA-A and HLA-B matching.

PURPOSE: To evaluate long-term follow-up of high-risk corneal transplants allocated after matching for broad HLA-A and HLA-B antigens and to establish whether matching for HLA-A and -B antigen "splits" would result in a reduced risk of immunologic graft failure. METHODS: A total of 303 high risk corneal transplants was included. Class I antigen-matched donor corneas were obtained using broad HLA-A and -B antigen data and accepting 0 or 1 mismatch at each locus. Analysis of HLA antigens was performed also on the split typing level. The influence on immunologic graft failure for an increasing number of matched class I antigens based on split typing was analyzed with Kaplan-Meier statistics and Cox regression. Graft survival and indication for transplantation were investigated. RESULTS: Rejection was the cause of 34% of all graft failures. A significantly higher immune failure free graft survival was found in a group with 0 or 1 HLA-A and -B mismatch based on split typing (log-rank test, P = 0.002). A beneficial effect of matching for split antigens was shown with multivariate analysis (odds ratio, 0.41). CONCLUSIONS: One third of graft failures in our high-risk population was caused by irreversible graft rejection. Allocation of donor corneas based on a 0 or 1 split antigen mismatch at both HLA-A and -B loci could contribute to a higher immune failure free graft survival and could result in a higher overall graft survival.

Sensitivity and specificity of the GDx: clinical judgment of standard printouts versus the number.

PURPOSE: The Number is a standard parameter of the GDx that reportedly distinguishes normal and glaucomatous eyes. The authors evaluated the sensitivity and specificity of the Number and examined whether expert clinical judgment of GDx printouts leads to a better separation. MATERIALS AND METHODS: Two experienced observers judged 800 GDx scans on 400 randomly presented printouts from 200 glaucoma patients and 200 age-matched normal subjects. The diagnosis was based on the symmetry analysis printout and was per patient rather than per eye. The observers assessed sensitivity for all glaucoma patients together, and separately for mild, moderate, and severe glaucoma. Their specificity was determined in the group of normal subjects. The same procedure was performed for the Number, at various critical values. RESULTS: Both observers discriminated better than the Number. At a critical value of 23, the specificity of the Number was 81.5%, which matched the lowest specificity of the 2 observers: 82.5% and 92.0% for observers 1 and 2, respectively. At these specificities, the sensitivity of the 2 observers and of the Number were 92.0%, 89.5%, and 85.5%, respectively. The sensitivity increased with the severity of glaucoma. The Kappa values for intraobserver agreement were 0.80 and 1.0. CONCLUSIONS: The Number yielded acceptable sensitivity and specificity values at a critical value of 23 in this test population. However, the clinical judgments of the printouts by both expert observers resulted in a better separation between normal and glaucomatous eyes, particularly in the group with mild glaucoma.

Sensitivity and specificity of new GDx parameters.

PURPOSE: The GDx is a scanning laser polarimeter that assesses peripapillary nerve fiber layer thickness. In addition to the 14 existing outcome parameters, four new parameters have been described recently: the Ellipse Standard Deviation (ESD), the Normalized Superior Area (NSA), the Normalized Inferior Area (NIA) and the Discriminant Analysis (DA). The aim of this study was to investigate the sensitivity and specificity of these four new parameters. METHODS: Only one randomly selected eye of 263 healthy volunteers and 241 glaucoma patients was considered. The healthy group was randomly divided into a reference set (n = 132) to calculate the tenth percentile of the normal distribution and a test set (n = 131) to calculate the specificity against these newly established cut-off points. Sensitivity was calculated for all glaucoma patients (n = 241) and again for three separate subgroups: early glaucoma (n = 90), moderate glaucoma (n = 93), and advanced glaucoma (n = 58). RESULTS: When the tenth percentile of the normal distribution was used as a cut-off point, the sensitivity and specificity pairs of the new parameters were 61.8% and 87.6%, 61.8% and 89.1%, 50.2% and 92.2% and 72.6% and 95.3% for the ESD, NSA, NIA, and the DA, respectively. The Area under the ROC curve was 0.86, 0.86, 0.87, and 0.90, respectively. Among the existing parameters, the Number discriminated best (sensitivity and specificity: 76.8% and 89.1%, respectively; area under the ROC curve: 0.90). When compared with The Number, the DA was equally good, whereas the other three new parameters performed statistically significantly worse. In general, the area under the ROC curve increased from early to moderate to advanced glaucoma. CONCLUSIONS: The new GDx parameters discriminated well between normal subjects and glaucoma patients. None of the new parameters discriminated better than The Number.

Adherence improvement in Dutch glaucoma patients: a randomized controlled trial.

PURPOSE: To study the effect of patient education and the TravAlert(®) -Eyot(®) drop guider on intraocular pressure (IOP) and adherence in patients with primary open angle glaucoma (POAG) or ocular hypertension (OHT) monitored with the TravAlert(®) dosing aid. METHODS: Multicentre, randomized, controlled clinical trial among 18 Dutch hospitals. Patients were randomized to one of the four study arms: (1) use of the dosing aid, (2) use of the dosing aid with the drop guider, (3) use of the dosing aid together with patient education or (4) use of the dosing aid and drop guider together with patient education. IOP was recorded at baseline and after 3 and 6 months. Data on adherence generated by the dosing aid were collected and studied at the end of the study. RESULTS: Mean IOP dropped from 20.3 ± 5.7 mmHg at baseline to 16.3 ± 4.0 mmHg (right eye) after 6 months and from 20.2 ± 5.9 mmHg to 16.4 ± 4.1 mmHg (left eye). The mean adherence rate was 0.91 ± 0.1. IOP and adherence rate were not statistically different between the study arms. Patients with 'drug holidays' had a significantly higher mean IOP after 6 months. Patients who used the drop guider were less adherent. A lower adherence level was also associated with new patients with glaucoma and patients with a lower level of knowledge on glaucoma. CONCLUSION: Patient education is especially useful for new patients with glaucoma. The use of a drop guider does not improve adherence. Especially patients with 'drug holidays' are at risk for developing uncontrolled IOP levels.

Motion artifacts in scanning laser polarimetry.

PURPOSE: The GDx (Laser Diagnostic Technologies, San Diego, CA) is a scanning laser polarimeter that measures retardation to assess retinal nerve fiber layer thickness in vivo. Eye movements during image acquisition may result in motion artifacts in the GDx image. The aims of this study were to investigate the effect of motion artifacts on the retardation values and to illustrate how motion artifacts can be identified. DESIGN: Observational case series. PARTICIPANTS: Thirty-two normal subjects and 28 glaucoma patients participated. METHODS: We imaged all 60 subjects with the GDx. Images with identified motion artifacts were compared with images without motion artifacts from the same eye and the same session. In 25 cases, the artifact was identified in the superior segment only, and the effect on the superior maximum parameter was calculated. In 26 cases, the artifact was observed in the inferior segment only, and the effect on the inferior maximum parameter was calculated. In nine cases, the artifact was observed superiorly and inferiorly, and the effect on both parameters was calculated. In all 60 cases, the effect on The Number (a summary parameter) was calculated. We also analyzed the groups of glaucoma patients and normal subjects separately. MAIN OUTCOME MEASURES: Superior maximum parameter, inferior maximum parameter, The Number parameters. RESULTS: In general, the identified motion artifacts led to an increase in retardation, reflected by an increase in the superior maximum and inferior maximum parameter by 5.9 micro m and 3.4 micro m, respectively (P < 0.001). The Number decreased by 3.4 with motion artifacts (P = 0.001). The variability of this effect was large. In one case, the motion artifact increased retardation by as much as 28.6 micro m. The effect of motion artifacts was greater in glaucoma patients than in normal subjects. CONCLUSIONS: The identified motion artifacts generally increase retardation values. This increase, however, is highly variable. Therefore, images with such motion artifacts should be viewed with caution or excluded from analysis.

Visualization of localized retinal nerve fiber layer defects with the GDx with individualized and with fixed compensation of anterior segment birefringence.

PURPOSE: To compare the visualization of localized retinal nerve fiber layer (RNFL) defects in GDx images with fixed and with individualized compensation of anterior segment birefringence (FC and IC, respectively) with their visualization in red-free fundus photographs. DESIGN: Observational case series. PARTICIPANTS: Eight eyes of six glaucoma patients with localized, wedge-shaped RNFL defects in red-free fundus photographs with matching visual field defects. METHODS: We imaged all eyes with a GDx equipped with a variable corneal compensator (VCC). The VCC replaced the standard fixed compensator and could be set to compensate for birefringence of up to 120 nm at any axis. Individual anterior segment birefringence was estimated from a macular retardation profile that resulted from the interaction between birefringence of the anterior segment and that of Henle's fiber layer. Measurements of RNFL retardation were made with the GDx with FC (60 nm of retardation with a slow axis of 15 degrees nasally downward) and with IC. Maps of retardation measurements with FC and IC were superimposed on red-free fundus photographs. MAIN OUTCOME MEASURES: Visualization of localized RNFL defects. RESULTS: Localized RNFL defects were visible in GDx retardation maps obtained with IC. The defects closely matched those observed in red-free fundus photographs. With FC, however, the GDx retardation images did not correlate well with red-free fundus photography. CONCLUSIONS: An individualized anterior segment compensation in the GDx improves the visualization of localized glaucomatous loss.