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The pupil in glaucoma

Shwe Tin, A; (2016) The pupil in glaucoma. Doctoral thesis , UCL (University College London). Green open access

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Abstract

Glaucoma is the most common preventable cause of blind-registration in elderly Western populations. Case-finding is crucial for the prevention of blindness. There is no single test that can reliably diagnose glaucoma, especially early cases. The relative afferent pupillary detect (RAPD) is known to be sensitive in the detection of optic nerve pathology. The clinical swinging flash light test is well used for this purpose. However, the test requires skill and careful interpretation, and the sensitivity of the test is limited to ≥0.3 log units of relative pupillomotor deficit. Some of the newly-built commercially available pupillometers measure the pupil parameters with accuracy. These instruments have mainly been used in the area of refractive surgery. This thesis considers the applicability of the commercially available pupillometer P3000 to the diagnosis of glaucoma. In this thesis a pupillometer (P3000) was calibrated before the stimulus parameters were tested for their best suitability for the RAPD test. The stimulus and outcome parameters were optimised. The chosen stimulus configuration (0.4s-1.6s on-off combination) produced repeatable results. The eyes were dark adapted only for 30 seconds before each test sequence for practical use in clinics. The pupillographic RAPD was calculated from the pupil constriction amplitudes calibrated in response to 3 levels of light stimulus. Data was collected on normal and glaucomatous subjects. There was no significant diurnal variation in the RAPD noted for both cohorts and the immediate repeatability was high. The final test was used in a methods comparison study to detect glaucoma against the gold standard of clinical diagnosis. The area under the Receiver Operating Characteristic curve for the detection of all grades of unilateral or bilateral glaucoma was in the region of 0.81 for the cohort of 101 normal and 117 glaucoma patients. Pupillometry may be helpful as an adjunctive test in the detection of glaucoma.

Type: Thesis (Doctoral)
Title: The pupil in glaucoma
Open access status: An open access version is available from UCL Discovery
Language: English
Additional information: Third party copyright material has been removed from ethesis.
UCL classification: UCL
UCL > Provost and Vice Provost Offices
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Brain Sciences
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Brain Sciences > Institute of Ophthalmology
URI: https://discovery.ucl.ac.uk/id/eprint/1485805
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