Diabetic eye disease in the west of Scotland

Ghafour, Issam M. Abdul (1983) Diabetic eye disease in the west of Scotland. PhD thesis, University of Glasgow.

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Abstract

This thesis reports the results of an investigation into some aspects of diabetic eye disease. The first three chapters give an account of the present state of knowledge of diabetes mellitus and diabetic retinopathy. In chapter 4 the multifactorial aetiology of diabetic retinopathy is discussed. In relation to this a study of the possible role of blood and plasma viscosity in the pathogenesis of diabetic retinopathy is reported. It was found that in diabetes blood and plasma viscosities are increased. Diabetics with proliferative retinopathy were found to have higher blood viscosity, at both high and low shear rates, than diabetics with background or no retinopathy. Diabetics with serious forms of retinopathy had higher fibrinogen levels than controls. Chapter 5 reports results of a study carried out in general practice to determine the prevalence of diagnosed diabetes in the West of Scotland. In Chapter 6 results of an investigation into the most practical means for the screening and detection of diabetic retinopathy are reported. This work was carried out in collaboration with ophthalmologists, opticians, physicians, and technicians from the Tennent Institute of Ophthalmology and Glasgow Royal Infirmary. Ophthalmoscopy was found to be a reliable tool for the purpose of screening for diabetic retinopathy. Ophthalmologists and trained and interested physicians were equally efficient in this respect. Other investigations such as fluorescein angiography, tests of colour vision, contrast sensitivity to grating patterns, and measurement of visual fields were time consuming, costly and needed highly specialised instruments which might not necessarily be available in centres concerned with early detection of serious diabetic retinopathy. Diabetic subjects had lower contrast sensitivity to grating patterns, compared to normal subjects, as measured by the Arden grating test. Contrast sensitivity was inversly proportional to the degree and severity of retinopathy. The severity of diabetic retinopathy also affected colour discrimination. The most seriously affected were those with exudative retinopathy. The study also confirmed that measurements of visual acuity are not a good indication of the severity of retinopathy. On the basis of results of the above study funduscopic examination of 400 consecutive diabetics attending a large hospital diabetic clinic, Glasgow Royal Infirmary, was performed (Chapter 7). This work was carried out to determine the prevalence of diabetic retinopathy in this population of diabetic individuals. A similar study was carried out on diabetics attending general practice (chapter 8). Identified diabetics were asked to attend for a full physical, including an eye examination. 35 per cent of patients were found to have ophthalmoscopically recognisable diabetic retinopathy. The onset of blindness was earlier in diabetic males than females. Diabetics were found to be registered as visually handicapped at an earlier age than the non-diabetic blind individuals (Chapter 9). In Chapter 10 an account is given of the indications, techniques, and advantages of photocoagulation in the treatment of diabetic retinopathy. Visual results of major studies carried out in this respect are summarised. A study of the short-term effects of laser therapy and exposure to high intensity light from ophthalmic instruments was carried out on patients attending the Tennent Institute (Chapter 11). Normal volunteers and diabetic patients were exposed to the tungsten light of a slit-lamp microscope. Also diabetics who received laser treatment for proliferative diabetic retinopathy were studied. Visual acuity on Snellen's Chart, colour vision as determined by the Farnsworth-Munse1l 100-Hue test, and contrast sensitivity measured by Arden grating test were all determined before, 20 minutes, and 24 hours after exposure. These visual functions were not found to be significantly affected by laser therapy or exposure to ophthalmic instruments during photocoagulation or a slit-lamp examination although the majority of normal and diabetic patients showed a temporary drop in visual acuity 20 minutes after light exposure, in all cases returning to within 1 line of Snellen's Chart. In the final chapter (12) various conclusions from the proceeding chapters are discussed and some recommendations are made with regard to the desirability and design of screening programmes for the early detection of diabetic retinopathy.

Item Type: Thesis (PhD)
Qualification Level: Doctoral
Additional Information: Adviser: W S Foulds
Keywords: Epidemiology, Ophthalmology
Date of Award: 1983
Depositing User: Enlighten Team
Unique ID: glathesis:1983-73738
Copyright: Copyright of this thesis is held by the author.
Date Deposited: 14 Jun 2019 08:56
Last Modified: 14 Jun 2019 08:56
URI: https://theses.gla.ac.uk/id/eprint/73738

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