Abstract
Purpose: :
To assess the usefulness of Optical Coherence Tomography (OCT) in identifying and tracking optic nerve swelling and non–glaucomatous optic atrophy. OCT provides a high resolution two–dimensional cross–sectional image of retinal tissue and the optic nerve. Its usefulness in measuring the retinal nerve fiber layer (RNFL) has already been well established in the diagnosis and management of glaucoma. Our study seeks to investigate whether it may aid in the diagnosis and monitoring of neuro–ophthalmologic optic nerve diagnoses.
Methods: :
A retrospective chart review was conducted on all Neuro–ophthalmology patients who received OCT imaging (Stratus version 4.0) between January 6, 2004 and June 31, 2005. The charts of patients with either optic nerve head swelling or non–glaucomatous optic atrophy were then reviewed, and the clinical impression and fundus photographs were compared with results of OCT scans. In the optic atrophy subgroup, a total of 206 OCT scans of 94 patients were reviewed. The disc swelling subgroup consisted of 72 OCT scans of 27 patients. Each scan was graded based on how well the OCT was able to document RNFL atrophy or swelling, in comparison with the normative database, and whether the location of the abnormality correlated with the clinical exam.
Results: :
In comparison with the normative database, OCT results correlated with the clinical impression of optic atrophy, showing RNFL atrophy in 87% of eyes [95% CI: 82–92%]. OCT correlated with the clinical impression of disc swelling, showing RNFL thickening in 90% of eyes [95% CI: 64–86%]. These percentages represent the respective sensitivity of the test in detecting atrophy or swelling when compared with the current gold standard: the clinical exam. In addition, a subset of fifteen patients with disc swelling had more than one OCT. The OCT seemed to be a useful objective tool in monitoring the edema in this sub–group.
Conclusions: :
OCT appears to be a useful tool for detecting and monitoring retinal nerve fiber layer atrophy and swelling in most cases.
Keywords: neuro-ophthalmology: optic nerve • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • nerve fiber layer