F.L. Ferris

Ocular Side Effects Associated with Peribulbar Injections of Triamcinolone Acetonide for Diabetic Macular Edema

Purpose: To evaluate long-term effects of anterior and posterior peribulbar injections of triamcinolone acetonide on intraocular pressure (IOP) elevation and cataract development. Methods: This study reports on IOP and cataract progression through 2 years in 96 eyes with diabetic macular edema randomized to focal/grid photocoagulation, 20 mg triamcinolone acetonide anterior injection, anterior injection followed by laser, 40 mg triamcinolone acetonide posterior injection, or posterior injection followed by laser. Results: Intraocular pressure increased from baseline by ≥10 mmHg at ≥1 visit through 2 years in 2 eyes (8%) in the laser group, 11 eyes (31%) in the anterior groups, and 6 eyes (17%) in the posterior groups. Among phakic eyes at baseline, 0, 5 (17%), and 1 (3%) in the 3 groups, respectively, underwent cataract surgery before the 2-year visit. Conclusion: Based on this small randomized trial, it appears that over 2 years, anterior peribulbar triamcinolone acetonide injections are associated with an increased incidence of IOP elevation and an increased risk of cataract development compared with laser or posterior peribulbar injections. The association of posterior injections with IOP elevation is less certain. Although the study involved eyes with diabetic macular edema, the results should be relevant to other conditions treated with peribulbar corticosteroids.

Image Scaling Difference Between a Confocal Scanning Laser Ophthalmoscope and a Flash Fundus Camera.

BACKGROUND AND OBJECTIVE To evaluate scaling and measurement differences between flash and scanning laser fundus images. PATIENTS AND METHODS The authors analyzed fundus autofluorescence images of patients with geographic atrophy secondary to age-related macular degeneration imaged with both 30º confocal scanning laser ophthalmoscope (cSLO) and 50º flash fundus camera (FFC). Multiple vessel-crossing points served as landmarks. RESULTS The mean (±SD; range) scaling factor between cSLO and FFC images (by GRADOR) for the horizontal dimension was 1.217 (±0.0487; 1.0474-1.272) versus 1.138 (±0.0311; 1.0841-1.193) for the vertical dimension. The mean percentage difference between horizontal and vertical scaling factors was 7.48 (±2.29; 2.30-10.70). Refractive error (focus) and aperture size (or field of view of the image) were positively correlated and aspect ratio was negatively correlated with landmark pair measurements. CONCLUSION Inherent image-scaling differences between fundus autofluorescence imaging systems are not restricted to simple pixel-to-millimeter calibration variances, but appear to vary depending on measurement orientation. Differences should be considered when comparing measurements obtained using different imaging systems, particularly for clinical trials.

Optical Coherence Tomography Minimum Intensity as an Objective Measure for the Detection of Hydroxychloroquine Toxicity

Purpose As optical coherence tomography (OCT) minimum intensity (MI) analysis provides a quantitative assessment of changes in the outer nuclear layer (ONL), we evaluated the ability of OCT-MI analysis to detect hydroxychloroquine toxicity. Methods Fifty-seven predominantly female participants (91.2% female; mean age, 55.7 ± 10.4 years; mean time on hydroxychloroquine, 15.0 ± 7.5 years) were enrolled in a case-control study and categorized into affected (i.e., with toxicity, n = 19) and unaffected (n = 38) groups using objective multifocal electroretinographic (mfERG) criteria. Spectral-domain OCT scans of the macula were analyzed and OCT-MI values quantitated for each subfield of the Early Treatment Diabetic Retinopathy Study (ETDRS) grid. A two-sample U-test and a cross-validation approach were used to assess the sensitivity and specificity of toxicity detection according to OCT-MI criteria. Results The medians of the OCT-MI values in all nine of the ETDRS subfields were significantly elevated in the affected group relative to the unaffected group (P < 0.005 for all comparisons), with the largest difference found for the inner inferior subfield (P < 0.0001). The receiver operating characteristic analysis of median MI values of the inner inferior subfields showed high sensitivity and high specificity in the detection of toxicity with area under the curve = 0.99. Conclusions Retinal changes secondary to hydroxychloroquine toxicity result in increased OCT reflectivity in the ONL that can be detected and quantitated using OCT-MI analysis. Analysis of OCT-MI values demonstrates high sensitivity and specificity for detecting the presence of hydroxychloroquine toxicity in this cohort and may contribute additionally to current screening practices.