Investigating quality of life in inherited optic neuropathies: Evaluating patient experiences and outcome measures

Inherited optic neuropathies (IONs) are a group of rare eye diseases characterised by bilateral and progressive degeneration of the optic nerve due to mitochondrial dysfunction. The two most common IONs encountered in clinical practice are autosomal dominant optic atrophy (DOA) and Leber hereditary optic neuropathy (LHON). In both conditions, visual failure typically begins in the first three decades of life, with poor long-term visual prognosis. The overall aim of this study was to investigate the impact of vision loss on the quality of life (QoL) of people with IONs and evaluate the patient-reported outcome measures (PROMs) used to capture their experiences. The hypothesis of this study was that pre-existing PROMs were inadequate for capturing the experiences of affected individuals, warranting the development of a disease-specific PROM for use in clinical trials and as part of routine healthcare. This study was composed of four key components, each addressing a different aspect of the research aim: 1. A systematic literature review established that current PROMs inadequately covered the experiences of individuals with IONs, particularly psychosocial aspects, and the psychometric performance of these PROMs was insufficiently reported. These findings confirmed the need for an ION-specific PROM. 2. The measurement properties of two PROMs, the Visual Function Index and the National Eye Institute Visual Function Questionnaire, were evaluated by Rasch analysis. Both instruments demonstrated poor psychometric performance, reinforcing the need for an ION-specific PROM. 3. Qualitative studies, including focus groups and semi-structured interviews, explored the experiences of people with IONs across different countries and stages of vision loss. Vision loss affected physical capabilities, psychological and emotional wellbeing, and social aspects of life. The impact of IONs on psychosocial and emotional wellbeing was identified as a key theme, alongside challenges related to adapting to visual impairment and maintaining independence. 4. An ION-specific PROM, the Cambridge Mitochondrial Visual Impairment – Inherited Optic Neuropathy Impact Questionnaire (mitoVISION-IQ), was developed for adults with vision loss due to DOA or LHON. Comprising three separate unidimensional scales measuring ‘Visual Functioning’, ‘Social Functioning’, and ‘Mental Wellbeing’, the mitoVISION-IQ demonstrated good psychometric properties and was found to have high value and low burden for respondents. In conclusion, the work in this thesis establishes the inadequacy of current PROMs for capturing the full impact of vision loss in people with IONs, and provides a conceptually relevant and psychometrically valid ION-specific measure.

Name dc:type.qualificationname

Doctor of Philosophy (PhD)

Level dc:type.qualificationlevel

Doctoral

Grantor dc:publisher.institution

University of Cambridge

Year dc:date.issued

2024

Author dc:creator

• Chen, Benson

Advisor dc:contributor.advisor

• Yu Wai Man, Patrick

• inherited optic neuropathy
• optic atrophy
• quality of life
• patient reported outcome measure
• Rasch analysis

Licence

• https://apollo8-f-pro.lib.cam.ac.uk/bitstreams/51768736-86c8-48fc-aab6-a56cbc4ebccf/download
• http://purl.org/NET/rdflicense/allrightsreserved

Language dc:language

eng

Author Identifier

0000-0001-8214-0186

OAI identifier oai:identifier

oai:www.repository.cam.ac.uk:1810/377915