Biomedical subjects
Publications and source records attributed to Chad F Baker.
CASE REPORT: Sympathetic ophthalmia typically presents as bilateral granulomatous panuveitis that occurs after penetrating ocular injury. We describe a case of bilateral exudative retinal detachments in a patient with Turner syndrome and sympathetic ophthalmia. COMMENTS: To our knowledge, this is the first report of sympathetic ophthalmia in Turner syndrome.
CASE REPORT: We examined a unique case of stroke in a 29-year-old woman. Magnetic resonance imaging revealed isolated bilateral acute infarctions of the lateral geniculate bodies (LGB). Visual field testing demonstrated incongruous but homonymous bilateral visual field loss in a bow-tie configuration. COMMENTS: Isolated bilateral damage to the LGB is a rare event. Literature review has revealed only 4 previous incidents of bilateral damage to both LGB. We present a literature review and a case of bilateral LGB infarction producing visual field defects suggestive of bilateral lateral choroidal artery involvement in an individual with classic migraine.
BACKGROUND: Canada's vast size and remote rural communities represent a significant hurdle for successful monitoring and evaluation of diabetic retinopathy. Teleophthalmology may provide a solution to overcome this problem. We investigated the application of Joint Photographic Experts Group (PEG) compression to digital retinal images to determine whether JPEG compression could reduce file sizes while maintaining sufficient quality and detail to accurately diagnose diabetic retinopathy. METHODS: All 20 patients with type 2 diabetes mellitus assessed at a 1-day teleophthalmology clinic in northern Alberta were enrolled in the study. Following pupil dilation, seven 30 degrees fields of each fundus were digitally photographed at a resolution of 2008 x 3040 pixels and saved in uncompressed tagged image file format (TIFF). The files were compressed approximately 55x and 113x their original size using JPEG compression. A reviewer in Edmonton randomly viewed all original TIFF images along with the compressed JPEG images in a masked fashion for image quality and for specific diabetic retinal pathology in accordance with Early Treatment Diabetic Retinopathy Study standards. The level of diabetic retinopathy and recommendations for clinical follow-up were also recorded. Exact agreement and weighted kappa statistics, a measure of reproducibility, were calculated. RESULTS: Exact agreement between the compressed JPEG images and the TIFF images was high (75% to 100%) for all measured variables at both compression levels. Reproducibility was good to excellent at both compression levels for the identification of diabetic retinal abnormalities (K = 0.45-1), diagnosis of level of retinopathy (kappa = 0.73-1) and recommended follow-up (kappa = 0.64-1). INTERPRETATION: The application of JPEG compression at ratios of 55:1 and 113:1 did not significantly interfere with the identification of specific diabetic retinal pathology, diagnosis of level of retinopathy or recommended follow-up. These results indicate that JPEG compression at ratios as high as 113:1 has the potential to reduce storage requirements without interfering with the accurate and reproducible teleophthalmologic diagnosis of diabetic retinopathy. This pilot project demonstrates the potential for JPEG compression within a digital teleophthalmology viewing system.