Abstract
Abstract: :
Purpose: To evaluate absolute filling defects of the optic nerve head representing superficial capillary dropout in normal tension glaucoma (NTG), primary open–angle glaucoma (POAG), ocular hypertension (OHT) and healthy controls, and to correlate these filling defects to functional damage and clinical data. Methods: Forty patients with NTG (mean age 55 ±10 years), forty patients with POAG (mean age 55 ±11 years), forty patients with OHT (mean age 53 ±13 years), and forty age–matched healthy controls (mean age 54 ±11 years) were included in a prospective study. Video fluorescein angiograms were performed by means of a Scanning Laser Ophthalmoscope. The extent of absolute filling defects of the optic nerve head was assessed using digital image analysis of early phase of the angiograms (percentage of the disc area). Visual fields were obtained by automatic static perimetry (Humphrey Field Analyzer). Results: Absolute filling defects were significantly larger in patients with NTG (12.2 ±15.5%) and POAG (12.9 ±13.1%) compared to patients with OHT (1.2 ±3.6) and healthy controls (0.1 ±0.5%) (p<0.0001, ANOVA). The area under the Receiver Operating Characteristic (ROC) curve was 0.806 for NTG vs. healthy controls, and 0.812 for POAG vs. OHT. Absolute filling defects are significantly correlated to the global indices mean deviation (r=–0.63, p<0.0001), pattern standard deviation (r=0.61, p<0.0001), short term fluctuation (r=0.30, p=0.02) and corrected pattern standard deviation (r=0.62, p<0.0001) and significantly correlated to horizontal (r=0.50, p<0.0001) and vertical (r=0.53, p<0.0001) cup–to–disc–ratios. Conclusion: Fluorescein filling defects of the optic disc representing capillary dropout are present in NTG and POAG. The extent of these filling defects is correlated to visual field loss. Fluorescein angiography with quantitative analysis of filling defects may be a useful tool in the diagnosis and management of NTG and POAG.
Keywords: optic disc • imaging/image analysis: clinical • blood supply