Population screening is expensive, and few studies demonstrate the cost-effectiveness of targeted screening in high-risk groups such as those of African or Hispanic heritage or those with a family history of glaucoma. Vitreous traction on the RNFL can distort thickness measurements (blue arrows).
#Abnormal oct eye test portable#
4,5 Moreover, screening works best when OCT is combined with a clinical eye examination or with other strategies such as portable tonometry, fundus photography, and visual field testing. The diagnostic accuracy of OCT imaging is better with more advanced disease where visual field loss is present than with early glaucoma. Myopia, axial length, vitreous traction, and macular disease may also confound accurate scans and lead to a falsely classified diagnosis (Figure 1-3).Īlthough OHTS demonstrated that OCT can predict future visual field loss, other studies have shown that the sensitivity and specificity of this imaging technology depends on disease severity. Coexisting pathology may impede reliable measurement. Cataract, dry eye disease, and small pupils reduce signal strength and, therefore, scan quality. Although RNFL and macular thickness parameters can discriminate between healthy and glaucomatous eyes, 2,3 there are numerous sources of anomalous or inaccurate OCT scans. In glaucoma diagnosis and management, OCT supplements clinical optic nerve assessment with reproducible, quantitative measurements of the nerve head and peripapillary RNFL. The objective evaluation of the retinal nerve fiber layer (RNFL) is the fundamental appeal of OCT as a diagnostic ancillary device. These are anomalous optic nerves with absent cups and anomalous RNFL scans. The Ocular Hypertension Treatment Study (OHTS) showed that certain baseline optic nerve parameters measured by confocal scanning laser ophthalmoscopy predicted future visual field defects. OCT and visual field testing can detect both moderate and late disease, but only OCT can detect early disease, is easy for patients to use, is highly repeatable, and has a sufficiently low false-positive rate. It should be at least 85% sensitive and 95% to 98% specific to minimize false positives. Prevent Blindness America recommends that technology for screening be easy for a patient to use reliably, detect all moderate and advanced disease, and identify most early cases. There are mobile autorefractors, tonometers, fundus cameras, visual field methods, and now optical coherence tomography (OCT) devices. New technology may offer a solution as instruments become smaller and more portable. Its use for screening works best when the technology is combined with a clinical eye examination or with other strategies such as portable tonometry, fundus photography, and visual field testing.Optical coherence tomography is particularly effective at detecting early and preperimetric glaucoma in the office setting. The utility of optical coherence tomography for glaucoma screening remains in question.Many at-risk patients do not seek medical care until glaucoma is approaching the end stage.
0 kommentar(er)
