Nayak, Devaki (2018) Structure and function of the visual pathway in demyelinating optic neuropathy. Doctoral thesis, Keele University.

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Introduction: Multiple sclerosis is a disabling disease with impact on the social, financial and occupational life of an individual. Diagnosis of Multiple sclerosis even with the McDonald criteria, sometimes can take many years, by which time the patient has already accumulated significant disability. Hence the need for early diagnosis and prompt treatment for a better prognosis highlighted in different MS studies. Visual dysfunction in patients with Multiple sclerosis is a common finding. Asymptomatic visual loss has been highlighted in various studies. In the United Kingdom, studies have focused on genetics, environmental factors, assessment of neurological state (EDSS, MSFC) along with MRI of the brain and spinal cord. There is no single study in the UK that has looked at the visual pathway in Multiple sclerosis and correlated with the neurological outcomes.

Aim: Correlation of structure and function of visual pathway in Multiple Sclerosis

Methodology: We recruited 55 (110 eyes) patients with relapsing remitting MS and 25 controls (50 eyes) into this project with specific inclusion and exclusion criteria. Power calculations were done based on the parameters used for the study. Coefficient of reliability and variability was tested prior to the study in a subset of control patients. Logistic regression model with odds ratio was used to assess the ability of each test to differentiate disease from control. Subgroup analysis was done for the optic neuritis group and the group receiving disease-modifying therapy. Function of the visual pathway was assessed using Sloan contrast charts along with HRR colour chart and HVF indices. Structure of the visual pathway was mainly assessed using different protocols from Optical Coherence Tomography. Ethical approval was obtained through the North Midlands IRAS and Keele University.

Results: The structure of the visual pathway correlates significantly with function of vision. This in turn correlates with neurological function. Visual tests are more sensitive than neurological testing by EDSS and hence can be used in diagnosis and to determine prognosis in RRMS. GCIP index, EDI OCT and posterior pole protocols on OCT have revealed useful and valuable information that can be translated into clinical use to manage patients with MS.

Conclusion: Sloan contrast charts and HRR colour testing are sensitive measures of disease progression. Visual field test indices on the Humphrey’s field test closely relate to RNFL thickness on posterior pole OCT. GCIP and EDI-OCT show different clinico-pathological staging in MS. Visual parameters have synergistic power in evaluating the disease process in MS. Visual testing for structure and function is a valuable addition to the routine assessment of MS patients. Visual assessment helps in detection of the spectrum of disease in MS with specifics to the range of manifestations and severities of illness. Multiple sclerosis like many other diseases exhibit the iceberg phenomenon. The iceberg phenomenon describes a situation in which a large percentage of a problem is subclinical or otherwise hidden from view. Thus, only the "tip of the iceberg" is apparent to the clinician. Visual assessments help in uncovering disease below the sea level by early detection and subsequent better disease control. Visual studies in MS using the parameters in this study must be considered for routine use in our day to day practice in diagnosis and managing patients more effectively.

Item Type: Thesis (Doctoral)
Subjects: R Medicine > RE Ophthalmology
Divisions: Faculty of Medicine and Health Sciences > School of Medicine
Depositing User: Lisa Bailey
Date Deposited: 20 Jul 2018 14:37
Last Modified: 20 Jul 2018 14:37

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