Focal ischaemic normal pressure glaucoma versus high pressure glaucoma.

In a total group of 130 patients with Normal Pressure Glaucoma (NPG) twenty-six were classified as Focal Ischaemic NPG (FINPG). This subgroup has a typical defect at the disc with a comparable visual field defect in the corresponding half of the visual field. Visual field defects are more often seen in the upper than the lower half of the visual field. The defects in the upper half are on the average larger (stage 1.6) than those in the lower half (stage 0.9). Abnormalities of the chamber angle were observed in 12% of these patients, the same percentage as in the normal population. Hypertension and/or cardiovascular disorders were found significantly more frequently in FINPG patients (65.4%) than in a control group of High Pressure Glaucoma (HPG) patients (22.2%). Of the local vascular risk factors, papillary haemorrhages (46%) and choroidal sclerosis (30%) were seen significantly more frequently in FINPG than in HPG (11% and 0% respectively). The total amount of peripapillary atrophy (PPA) in FINPG and HPG is the same, but the distribution is clearly different: in FINPG there is more PPA on the side of the papillary defect. Wide veins were observed in a high percentage of cases in both groups. FINPGs were found to be more frequently progressive (38.5%) than had been thought at first. Recognition of subgroups in NPG, and of risk factors, has already made it possible to make a better prognosis in some types of NPG.