Abstract
Abstract: :
Purpose:To evaluate the detection of longitudinal retinal nerve fiber layer (RNFL) changes with Optical Coherence Tomograph (OCT). Methods:406 eyes qualified for this study, each having no less than 3 consecutive reliable visual field (VF) tests and 3 consecutive OCT scans during the same time period. Clinical ophthalmic examination was done at the time of testing. The interval between examinations was at least six months. 200 eyes were chosen randomly for further analysis. For each of the 100 OCT measuring points the individual measurement was subtracted from the age adjusted normative value and the mean difference and the standard deviation (SD) of the difference were calculated. This method is similar to the calculation of the mean deviation (MD) and pattern standard deviation (PSD) in VF test. The slope of the change along the consecutive sessions for both the mean difference (OCT MD) and the SD (OCT PSD) was defined by using linear regression. Four sub-groups were defined based on their slope of change; each includes 20 eyes as follows: 1. Stable OCT MD, 2. Steepest slope of the OCT MD, 3. Stable OCT PSD, 4. Steepest slope of the OCT PSD. For each eye the slope of change in the VF’s MD and the PSD was determined. The mean±SD of the slope of change was compared between the groups. Results: Conclusion:A higher rate of VF deterioration was found in eyes with high rate of RNFL thinning, utilizing the OCT MD analysis, compared to eyes with low rate of thickness changes. OCT PSD method was found to perform poorly. These findings give an indication of the usefulness of the OCT MD method for longitudinal assessment, however further evaluation is warranted.
Keywords: 432 imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • 431 imaging/image analysis: non-clinical