Abstract
Abstract: :
Purpose: To correlate the subjective perimetry findings of the PHP with the retinal images obtained with the OCT Ophthalmoscope. Background: AMD is the leading cause of blindness in developed countries. PHP is a newly available tool to screen for evidence of progressive AMD. PHP utilizes hyperacuity to monitor distortion . When the retinal pigment epithelium (RPE) and photoreceptors are elevated due to drusen or a choroidal neovascular membrane (CNV), there will be a shift in the perceived object location. This produces a hyperacuity defect. An artificial distortion is presented for comparison with the elevated area to obtain a quantitative measurement of the retinal elevation.This is called preferential looking analysis. The higher distortion will be the one noticed by the brain. Goldstein et al at on an unpublished study looked at 182 eyes with CNV and intermediate AMD with PHP. They found that the sensitivity to detect hyperacuity defects caused by CNV was 80.2% and the specificity was 87.7%. Retinal imaging has recently been revolutionized by Podoleanu et al. with the development of the Optical Coherence Tomography (OCT) Ophthalmoscopy. This instrument provides multiple corresponding views of the retina simultaneously and the capacity to evaluate the layers of the retina in the coronal plane. Methods: Thirteen eyes with the diagnosis of AMD (10 with exudative, 2 with non–exudative including and one with Basal Lenticular Drusen) where examined. Visual acuity with correction ranged from 20/40 to 20/160. PHP test was performed without dilation followed by OCT Ophthalmoscopy. Hyperacuity defects were correlated with the obtained images. Results: All the eyes with CNV had a positive test for hyperacuity defects. The same eyes showed elevation of the RPE by the membrane. Some eyes had a sensory detachment around the membrane without changes in the PHP. Of the eyes with non–exudative AMD one out of three had a positive test for hyperacuity defects. This eye had coalescing drusens. Conclusion: The hyperacuity defects that are noted by the PHP are produced from elevation of the RPE/photoreceptor layer as previously proposed. The elevated areas noted with the OCT Ophthalmoscopy corresponds with the defects noted on the PHP. Drusen can produce hyperacuity defects when they produce a significant elevation of the RPE/photoreceptor layer. Sensory retinal elevation alone does not produce hyperacuity defects. More extensive studies are in the future to further correlate anatomic changes with hyperacuity defects.
Keywords: imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound)