Tomographic identification of neuroretinal rim loss in high-pressure, normal-pressure, and suspected glaucoma.

Abstract

To identify progressive rim loss and describe patterns of regional change in various clinical presentations of glaucoma by scanning laser tomography (SLT). A previously described analytical approach was used to identify progressive rim area loss in SLT disc images of eyes of people with ocular hypertension (OHT, n = 97), early POAG (OHT converters; n = 30), asymmetric normal-pressure glaucoma (NPG, established and suspected in contralateral eyes; n = 26), and normal control subjects (n = 32). Analysis was performed longitudinally in individual image series, and cross-sectionally within groups at different time points. Reproducibly reduced rim area was detected in 2 (6.2%) of 32 normal control subjects, 11 (11%) of 97 OHT subjects, 27 (90%) of 30 OHT converters, 16 (58%) of 26 of suspected NPG eyes, and 15 (54%) of 26 of established NPG eyes (mean MD = -6.5 dB). Of 5 (19%) of 26 of suspected NPG eyes that converted on visual field testing, rim loss was detected in 3 of 5. In all groups, rim loss was common in the disc poles, especially inferiorly. Patterns of rim loss were similar within high-pressure and normal-pressure groups, whether or not eyes had field defects in each. In high-pressure groups, rim loss was more common nasally than temporally. Normal-pressure groups, unlike high-pressure groups, frequently had rim loss temporally. Suspected NPG eyes had more rim loss temporally and their rim area tended to be less compared with OHT and OHT converters, despite the three groups having equivalent baseline fields. There were similarities and differences in the pattern of rim loss in SLT disc images of high- and normal-pressure presentations of glaucoma. Progressive rim loss was detected in eyes without visual field defects, eyes that progressed to develop field defects, and eyes with established and more severe glaucoma.