The thesis evaluated, in three studies, the clinical potential of Critical Flicker Fusion perimetry (CFFP) undertaken using the Octopus 311 perimeter. The influence of the learning effect on the outcome of CFFP was evaluated, in each eye at each of five visits each separated by one week, for 28 normal individuals naïve to perimetry, 10 individuals with ocular hypertension (OHT) and 11 with open angle glaucoma (OAG) all of whom were experienced in Standard Automated perimetry (SAP). An improvement occurred in the height, rather than in the shape, of the visual field and was largest for those with OAG. The normal individuals reached optimum performance at the third visit and those with OHT or with OAG at the fourth or fifth visits. The influence of ocular media opacity was investigated in 22 individuals with age-related cataract who were naïve to both SAP and CFFP. All individuals underwent both CFFP and SAP in each eye at each of four visits each separated by one week. At the third and fourth visit, glare disability (GD) was measured with 100% and 10% contrast EDTRS LogMAR visual acuity charts in the presence, and absence, of three levels of glare using the Brightness Acuity Tester. The visual field for CFF improved in height, only. Little correlation was present between the various measures of GD and the visual field, largely due to the narrow range of cataract severity. The influence of optical defocus for both CFFP and SAP was investigated, in one designated eye at each of two visits, in 16 normal individuals all of whom had taken part in the first study. Sensitivity for SAP declined with increase in defocus whilst that for CFFP increased. The latter was attributed to the influence of the Granit-Harper Law arising from the increased size of the defocused stimulus.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:567411 |
| Date | January 2012 |
| Creators | Luraas, Knut |
| Publisher | Cardiff University |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://orca.cf.ac.uk/39684/ |
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