This study investigated the variability of response associated with various perimetric techniques, with the aim of improving the clinical interpretation of automated static threshold perirnetry. Evaluation of a third generation of perimetric threshold algorithms (SITA) demonstrated a reduction in test duration by approximately 50% both in normal subjects and in glaucoma patients. SITA produced a slightly higher, but clinically insignificant, Mean Sensitivity than with the previous generations of algorithms. This was associated with a decreased between-subject variability in sensitivity and hence, lower confidence intervals for normality. In glaucoma, the SITA algorithms gave rise to more statistically significant visual field defects and a similar between-visit repeatability to the Full Threshold and FASTPAC algorithms. The higher estimated sensitivity observed with SITA compared to Full Threshold and FASTPAC were not attributed to a reduction in the fatigue effect. The investigation of a novel method of maintaining patient fixation, a roving fixation target which paused immediately prior lo the stimulus presentation, revealed a greater degree of fixational instability with the roving fixation target compared to the conventional static fixation target. Previous experience with traditional white-white perimetry did not eradicate the learning effect in short-wavelength automated perimetry (SWAP) in a group of ocular hypertensive patients. The learning effect was smaller in an experienced group of patients compared to a naive group of patients, but was still at a significant level to require that patients should undertake a series of at least three familiarisation tests with SWAP.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:285995 |
| Date | January 1998 |
| Creators | Pacey, Ian Edward |
| Publisher | Aston University |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://publications.aston.ac.uk/14648/ |
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