To investigate the clinical manifestation and the structural optic disc changes according to the development of reproducible visual field defects in a group of preperimetric patients converting to early glaucoma.

Standard automated perimetry (Humphrey Field Analyzer) was performed every six months in 294 preperimetric patients. Each subject was classified as either converter or non-converter according to glaucomatous visual field changes, and the clinical manifestations were analyzed retrospectively. Sequential optic disc images were obtained using the TopSS scanning laser ophthalmoscope (TopSS^TM) and optic disc parameters were measured to determine if any change had occurred.

A total of 44 eyes from 44 subjects (14.9%) in 294 patients subsequently developed early glaucomatous field loss (converters). The progression rate of visual field defect is 0.43dB/year. In respect to age, sex, refractive error, and diabetes mellitus, no significant differences were observed. Elevated IOP, hypertension, and family history of glaucoma were detected more frequently in the converter group than in the non-converter group. Among TopSS parameters, cup-to-disc ratio, effective area, volume above, maximum slope, and neuroretinal rim area showed statistically significant change. Changes of the neuroretinal rim were prominent in superior and inferior sectors.

Among TopSS parameters, cup-to-disc ratio, effective area, volume above, and neuroretinal rim are useful in detecting the progression of glaucoma. Furthermore, neuroretinal rim changes in each sector may provide clinically relevant information in detecting and monitoring the progression of glaucoma.