Fluorescein Filling Defects and Quantitative Morphologic Analysis ofthe Optic Nerve Head in Glaucoma

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Abstract
Objectives To evaluate absolute filling defects of the optic nerve head in normaltension glaucoma (NTG) and primary open-angle glaucoma (POAG) and to comparethe filling defects with topographic analysis of the optic disc. Methods Twenty-five patients with NTG, 25 patients with POAG, and 25 age-matchedcontrols were included. Fluorescein angiograms were performed by means ofa scanning laser ophthalmoscope. The extent of absolute filling defects ofthe optic nerve head was assessed using digital image analysis of early-phaseangiograms. Topographic measurements of the optic disc were acquired usingthe Heidelberg Retina Tomograph II. Results Absolute filling defects were significantly larger (P = .001) and were seen more often (P<.001)in patients with NTG (n = 18) and POAG (n = 19) compared with controls (n= 3). Rim area (P = .006), rim volume (P = .007), cup-disc area ratio (P = .008),linear cup-disc ratio (P = .005), maximum cup depth(P = .002), cup shape measure (P = .03), and nerve fiber layer thickness (P =.008) and cross-sectional area (P = .006) were significantlydifferent between patients with glaucoma and controls. Absolute filling defectswere significantly correlated with cup area (r =0.31; P = .007), rim area (r =−0.38; P<.001), rim volume (r = −0.35; P = .002), cup-disc arearatio (r = 0.49; P<.001),linear cup-disc ratio (r = 0.48; P<.001), cup shape measure (r = 0.27; P = .02), and nerve fiber layer thickness (r = −0.33; P = .004) and cross-sectionalarea (r = −0.30; P =.009). Conclusions Fluorescein filling defects of the optic disc are present in NTG andPOAG. The extent of these filling defects is correlated with the morphologicdisc damage.