Aim To evaluate the long-term perimetric fluctuation (LF) in patients with different stages of glaucoma according to the Glaucoma Staging System 2 (GSS2).
Methods This multicentre retrospective study included 161 eyes of 161 stable glaucoma patients undergoing four visual-field tests (Humphrey SITA-Standard program over the central 24° or 30°) over a 2-year period. For each patient, the stage of the disease was classified according to GSS2. LF was then calculated as the mean of the standard deviations of point-to-point threshold sensitivities in the four repetitions. LF in GSS2 stages was compared using the t test.
Results LF progressively increased from stage 0 to stage 4, and then decreased at stage 5. Stage 4 had a peak of 3.19±0.94 dB, with statistically significant differences compared with all the other stages. The lowest LF (1.65±0.60 dB) was found for normal subjects, whereas similar data were found for borderline patients and those at stages 1 and 5 (2.09±0.58, 2.13±0.57 and 2.22±0.89 dB, respectively; p>0.13). Visual fields with generalised defects had a lower LF (1.90±0.81) than those with mixed (2.84±0.87, p=0.0003) and localised (2.63±0.72, p=0.004) defects.
Conclusions In this study, the authors showed that the lower the visual-field defect, the lower was LF, except at stage 5 of GSS2. As test–retest changes exceeding LF could represent a sign of progression, the authors suggest that clinicians using this classification system calculate LF, in order to better differentiate true progression from variability.
- Primary open-angle glaucoma (POAG)
- visual field
- long-term fluctuation
- long-term variability
- glaucoma staging system
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Preliminary results were presented at ARVO, Fort Lauderdale, USA, May 2007.
Competing interests None.
Patient consent Obtained.
Ethics approval Ethics approval was provided by the San Paolo Hospital.
Provenance and peer review Not commissioned; externally peer reviewed.