Optic nerve head changes in early glaucoma: a comparison between stereophotography and Heidelberg retina tomography.

OBJECTIVE: To evaluate and compare the diagnostic accuracy of the Heidelberg retina tomograph (HRT) version 3 with that of glaucoma specialists using stereophotography in discriminating between normal eyes and patients with early glaucomatous visual field loss. METHODS: A total of 105 eyes of 105 individuals were prospectively and consecutively recruited. The sample comprised 51 normal and 54 early glaucomatous eyes, as defined by intraocular pressure and standard automated perimetry results, regardless of optic disc appearance. Receiver operating characteristic (ROC) curves were plotted for the HRT3 parameters and a linear discriminant function (LDF) developed in our hospital. Best sensitivity-specificity pairs were compared between the HRT3 parameters, with the highest areas under the ROC curve (AUCs) and evaluation of optic disc stereophotographs. Agreement between methods for measuring vertical cup-to-disc ratio was evaluated with the Bland-Altman plot. RESULTS: The average visual field mean deviation was -2.90 dB. The HRT3 parameters with the largest AUCs were our LDF (0.900), rim volume (0.883), and vertical cup/disk ratio (0.880), with no significant differences between these parameters. Sensitivity-specificity pairs were 79.6-100% (clinical evaluation), 83.3-86.3% (our LDF), 64.8-96.1% (final glaucoma probability score), and 68.5-90.2% (global Moorfields regression analysis). CONCLUSIONS: The diagnostic accuracy for differentiating normal eyes from those with early visual field defects was similar between clinical evaluation of the optic disc and evaluation with the HRT3. The use of our LDF increased the sensitivity-specificity balance with respect to the HRT-provided parameters. The diagnostic accuracy of the HRT classifications was comparable to that of an experienced glaucoma specialist.

Diagnostic ability of a linear discriminant function for optic nerve head parameters measured with optical coherence tomography for perimetric glaucoma.

BACKGROUND/AIMS: To calculate and validate a linear discriminant function (LDF) for optical coherence tomography (OCT) to improve the diagnostic ability of isolated optic nerve head (ONH) parameters to discriminate between healthy individuals and glaucoma patients. METHODS: Two independent samples (teaching and validating sets) were prospectively selected. The teaching set (54 normal eyes and 73 glaucoma patients) was used to calculate the LDF. The validating set (70 healthy individuals and 67 glaucoma patients) was used to test the performance of the LDF in an independent population. Receiver operating characteristic (ROC) curves were plotted and compared with the ONH parameters measured using OCT. RESULTS: The optimized function was: LDF=8.204+(2.59xdisc area)-(9.25xhorizontal rim width). The largest areas under the ROC curve were 0.923 and 0.898 for our LDF and the vertical rim area in the validating population respectively. There were no significant differences between the areas. At 95% fixed specificity, the LDF (71.64%) and the vertical rim area (65.67%) yielded the highest sensitivity values. CONCLUSIONS: All ONH parameters obtained with OCT, except disc area, had a good ability to differentiate between healthy and glaucoma individuals. As judged by the area under the ROC curve, the LDF performed better than any single parameter, although statistics did not prove it better than vertical cup/disc ratio or vertical rim area with the number of subjects we studied.

Scanning laser polarimetry: logistic regression analysis for perimetric glaucoma diagnosis.

PURPOSE: To calculate and validate a linear discriminant function (LDF) for scanning laser polarimetry (SLP) with variable corneal compensation (GDx-VCC) to increase the diagnostic accuracy when using isolated retinal nerve fibre layer (RNFL) parameters to discriminate between healthy and glaucomatous eyes with visual field loss. METHODS: We prospectively selected two independent samples (teaching and validating sets). The teaching set, comprising 71 consecutive healthy subjects and 73 patients with open-angle glaucoma, was used to calculate the LDF. The validating set, comprising 72 consecutive normal eyes and 76 glaucoma patients, was used to test the performance of the LDF in an independent population. Receiver operating characteristic (ROC) curves were plotted for the validating set to evaluate the diagnostic accuracy of the LDF and the SLP parameters. RESULTS: The obtained function was LDF=-12.20+(0.15 x nasal average)-(23.85 x normalized inferior area)+(1.18 x maximum modulation). The areas under the ROC curve were 0.901 and 0.893 for our LDF and 0.893 and 0.877 for the nerve fibre indicator (NFI) in the teaching and validating populations, respectively. There were no significant differences between these values (P=0.743 in the teaching set, and P=0.458 in the validating set). NFI was the SLP-provided parameter with the best sensitivity-specificity balance. Sensitivities were 57.89% for the LDF and 48.68% for NFI at 95% fixed specificity. CONCLUSIONS: The LDF and NFI were the most accurate SLP parameters for diagnosing glaucoma. The LDF yielded the highest sensitivity at 95% fixed specificity to discriminate between normal and glaucoma subjects.

[Retinal toxicity following chloroquine therapy]. / Toxicidad retiniana secundaria a tratamiento con cloroquina.

CASE REPORT: Two cases of bilateral ocular toxicity following chloroquine therapy in two women with systemic lupus erythematosus are presented. DISCUSSION: Retinal toxicity due to chloroquine is an uncommon iatrogenic disease. It is dose-dependent. New cases are still being described despite the application of ophthalmic screening techniques.