Use this URL to cite or link to this record in EThOS: https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.796716
Title: Clinical and experimental studies on normal and dry eyes
Author: Refaat, Refaat F.
Awarding Body: University of Glasgow
Current Institution: University of Glasgow
Date of Award: 1992
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Abstract:
The clinical manifestations of dry eye are a common complaint which accounts for about 10% of patients attending a general ophthalmic clinic. Dry eyes are commonly caused by a deficiency in one or more of the constituents ot the tear film, an irregularity of the ocular surface or a defect in the lid margin. The treatment of dry eye has been directed generally to the relief of symptoms as there is no permanent cure in the majority of cases, The tear film is a complex trilaminar structure. It plays an important function as an extra layer situated between the lid and the ocular surface, The formation of the tear film within a very short period of time, from three different types of glands situated at different parts of the eyelid and the ocular surface, is one of the most fascinating observations in ophthalmology. However the present knowledge of the different aspects that influence the tear film is incomplete. This thesis includes clinical trials and laboratory research using "Millipore filter paper" which has the advantage of removing one or maybe two layers of the conjunctiva under local anaesthesia. The conjunctival cells were examined under light and electron microscopy. Vitamin A as Retinol acetate eye ointment was used on patients with Sjogren's syndrome who have also dry eye symptoms. The aim of this trial was to assess the effect of retinol acetate on the conjunctival epithelium. The thesis is divided into two parts. The first half includes a general reviews of the tear film and vitamin A. The first chapter is a brief historical account of our knowledge of the anatomy and physiology of the lacrimal glands and the tear film from ancient times to the present day. It also gives a brief historical account of the clinical manifestations of dry eyes and the different modalities of treatment. In the second chapter, a brief anatomical description of the conjuntiva, the goblet cells, the main and accessory lacrimal glands and the meibomian glands, which all contribute to the formation of the trilaminar structure of the tear film with an analysis of the normal composition of the tear film. There is a section on the clinical manifestations and diagnostic tests of dry eye with an emphasis on Sjogren Syndrome. The last part of this chapter deals with the present day management of dry eyes and the new drugs that hopefuly will give a longer relief of symptoms in the near future. Vitamin A was used topically for the treatment of dry eyes with Sjogren syndrome patients. For this reason a brief history of Vitamin A was included in chapter three. In chapter four a brief review of the structures and properties of vitamin A. This includes a very brief description of the types of vitamin A and its effects on the body. Vitamin A is an essential nutritional substance and therefore its deficiency or excess is harmful. These effects Include night blindness and degenerative changes on the conjunctiva and the cornea. Impression cytology is a new technique which assess the conjunctival epithelial cells under light microscopy. It is a quick non-invasive test with wide applications, "Millipore filter paper" is used to remove one or two layers of the conjunctiva at one time. Chapter five is a description of a clinical and a laboratory trial to choose the better filter paper surface with the maximum number of cells and the minimum amount of mucus. It showed that the dull surface of the filter paper gives a better yield of cells than the smooth surface, Chapter six is a double blind clinical trial of the effect of topical retinol acetate on patients with Sjogren syndrome. The results of the trial showed a reduction of foreign body sensation and photophobia in two third of cases but it has no significant improvement on the burning and itchy sensation. There was no significant improvement on the tear meniscus or Break-up time. Chapter seven includes an attempt to culture a first line cell culture using "Millipore filter paper". Then the cell cultures were tested with therapeutic and toxic doses of vitamin A. The result showed that the cell culture continue to multiply with the therapeutic doses but showed minimal growth with the toxic doses. Scanning Electron microscopy was used to examine the deeper layers of the conjunctiva by using "Millipore filter paper". This is a new technique which has not been used before and has wide clinical applications. Also the superficial conjunctival epithelial layer was examined from patients with Sjogren syndrome. It showed cuboidal and columnar shaped epithelial cells.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (D.Sc.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.796716  DOI: Not available
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