Parapapillary atrophy in patients with focal visual field loss

To examine parapapillary atrophy in normal subjects and patients with primary open-angle glaucoma with focal visual field loss.

Twenty-nine patients with repeatable early focal visual field loss according to standard automated perimetry (Humphrey program 24-2) and 29 matched (age and disk area) normal subjects were included. Parapapillary atrophy area and optic disk topography were evaluated with a confocal scanning laser ophthalmoscope. The difference in parapapillary atrophy area between normal subjects and patients with glaucoma was examined. Optic disk topography was evaluated by means of the rim-disk area ratio in 36 10-degree sectors and classified into diffuse and focal patterns of neuroretinal rim thinning. In patients with a focal pattern, the locations of rim thinning and parapapillary beta zone atrophy were compared.

Beta zone atrophy was detected more frequently in patients with glaucoma (45% [13/29]) than in normal subjects (7% [2/29]), and it was located both superiorly and inferiorly in 92% (12/13) of the glaucoma patients. Alpha zone atrophy was significantly larger in patients with glaucoma than normal subjects (P = .009) but not more frequent (97% [28/29] in both groups). Sixty-one percent (8/13) of glaucoma patients with beta atrophy had diffuse thinning and 31% (4/13) had focal thinning. Eight percent (1/13) did not have neuroretinal rim thinning. In the four patients with both focal rim thinning and beta zone atrophy, the location of rim thinning corresponded to the location of the beta zone atrophy (100% [4/4]).

In patients with early focal glaucomatous visual field loss, the presence and location of parapapillary beta zone atrophy and neuroretinal rim thinning are in good correspondence. Observation of localized parapapillary beta zone atrophy in clinical practice should direct one to more closely examine the optic disk in this region, as it may reveal localized rim thinning in a disk previously considered to be normal. Moreover, diffuse structural change in an eye with only focal functional change, as determined by standard automated perimetry, is consistent with the possibility that structural damage may be more widespread than functional damage in these patients.