An International Study of Emotional Response to Bilateral Vision Loss Using a Novel Graphical Online Assessment Tool

Psychometric Validity of the Visual Function Index in Leber Hereditary Optic Neuropathy

Purpose

The purpose of this study was to determine the psychometric validity of the Visual Function Index (VF-14) for use by patients with Leber hereditary optic neuropathy (LHON).

Methods

Rasch analysis was conducted in two stages using data for 196 individuals (74.5% male) carrying one of the three primary LHON mutations and affected by vision loss. In stage 1, scale unidimensionality, scale-to-sample targeting, response category threshold ordering, item fit statistics, local dependency, and reliability were assessed. In stage 2, iterative post-hoc revisions of the VF-14 structure (VF-14R) were applied and psychometrically re-evaluated.

Results

Issues identified with the VF-14 included disordered response thresholds (12/14 items), local dependency (10/91 pairwise dependencies), and evidence of multidimensionality. However, the distribution of person estimates and item thresholds were fairly well matched, only one item showed misfit to the Rasch model, and there was good reliability (Person Separation Index 0.84). Rasch-informed VF-14 revisions included removing both driving items and the misfitting sports item, rescoring response options across all items by merging two response categories, and accounting for the dependency between two reading items. The VF-14R demonstrated improved psychometric validity.

Conclusions

Clinicians and researchers using the VF-14 with LHON patients should be aware of its limitations. Compared to the original version, the proposed Rasch-based structure of the VF-14R appears to offer improved psychometric performance and interpretation of vision-related activity limitation.

Translational Relevance

The original version of the VF-14 exhibits several limitations that undermines its psychometric validity as a patient-reported outcome measure for patients with LHON.

Solutions to a Radical Problem: Overview of Current and Future Treatment Strategies in Leber's Hereditary Opic Neuropathy

Leber's Hereditary Optic Neuropathy (LHON) is the most common primary mitochondrial DNA disorder. It is characterized by bilateral severe central subacute vision loss due to specific loss of Retinal Ganglion Cells and their axons. Historically, treatment options have been quite limited, but ongoing clinical trials show promise, with significant advances being made in the testing of free radical scavengers and gene therapy. In this review, we summarize management strategies and rational of treatment based on current insights from molecular research. This includes preventative recommendations for unaffected genetic carriers, current medical and supportive treatments for those affected, and emerging evidence for future potential therapeutics.

The Impact of Leber Hereditary Optic Neuropathy on the Quality of Life of Patients and Their Relatives: A Qualitative Study

BACKGROUND

Leber hereditary optic neuropathy (LHON) is an inherited mitochondrial disease characterized by severe bilateral vision loss and chronic visual impairment. The objective of this study was to comprehensively explore the impact of LHON on the lives of patients and their relatives at the time of diagnosis and now.

METHODS

Qualitative study design with 8 focus group interviews conducted in France, Germany, the United Kingdom, and the United States, involving 17 individuals with m.11778G>A mutation and their relatives. Separate focus groups for patients and their relatives were facilitated by a moderator in French, German, or English. Qualitative analysis of interviews using a pre-defined analytical framework.

RESULTS

Participants reported feeling devastated by the diagnosis of LHON after a lengthy and worrisome diagnostic journey. Patients were frustrated by the loss of autonomy, which also affected their relatives. Participants described challenges across several domains: physical capabilities, emotional well-being, interpersonal relationships, work and studies, finances, and recreational activities. Access to disability allowances, vision aids, and funded or subsided idebenone varied by country, resulting in unequal financial impact. Patients are hopeful for therapy that would restore autonomy and improve their ability to enjoy a fulfilling life, while alleviating the demands placed on their relatives.

CONCLUSIONS

The impact of LHON extends beyond vision-related activity limitations. Addressing the psychosocial impact of LHON and helping patients and their relatives adapt and cope with vision loss are vital. As part of this, an accurate and timely diagnosis is important to enable early intervention. Further investigation of specific unmet needs is required.

Capturing the experiences of patients with inherited optic neuropathies: a systematic review of patient-reported outcome measures (PROMs) and qualitative studies

PURPOSE

To identify and comprehensively evaluate studies capturing the experience of individuals affected by an inherited optic neuropathy (ION), focusing on patient-reported outcome measures (PROMs) and qualitative studies where the health status and quality of life (QoL) of these individuals have been explored.

METHODS

Systematic review of five databases using a search strategy combining four concepts: (1) ION; (2) QoL and health status; (3) PROMs; and (4) qualitative research. Studies assessing the impact of ION on any QoL domain using a PROM or qualitative methodology were included and appraised, using criteria based on the COSMIN checklist (for PROM studies) and the CASP checklist (for qualitative studies).

RESULTS

Of 1326 unique articles identified, six studies were included. Five PROMs were identified: Visual Function Index (VF-14); Hospital Anxiety and Depression Scale (HADS); a novel graphical online assessment tool (NGOAT) for reporting emotional response to vision loss; a new PROM informed by the DSM-V Criteria for Major Depressive Disorder; and an interpersonal and career 'impact rating' PROM. The psychometric performance of included PROMs were poorly described. Qualitative studies found that vision loss resulted in psychosocial losses including loss of social and communication skills and loss of independence and freedom. Factors that modified the response to vision loss were also identified.

CONCLUSION

The current PROMs used by individuals with ION have poor content coverage, primarily measuring activity limitation and emotional well-being, and insufficient reporting of psychometric performance. There is a need to develop a PROM for individuals ION to report their experiences of living with their condition.

Evaluation of Vision-Related Quality of Life in Chinese Patients With Leber Hereditary Optic Neuropathy and the G11778A Mutation

OBJECTIVE

To assess quality of life (QoL) measures in Chinese Leber hereditary optic neuropathy (LHON) patients with the G11778A mutation.

METHODS

Chinese LHON patients with the G11778A mutation were prospectively evaluated using the Visual Function Index (VF-14) at 6 months, 1 year, and 3 years after the involvement of the second eye. Patients who completed the VF-14 at all 3 follow-up time designations were included in the analysis.

RESULTS

Fifty-five patients met the inclusion criteria. The median age of patients when their vision was bilaterally affected was 16.3 years old (interquartile range: 13.9-18.3 years). In our patient cohort, 89.1% (n = 49) were male, and the ratio of males to females was 8.2:1. The median logMAR visual acuity was 2.0 (interquartile range: 1.0-2.6). The mean VF-14 scores of patients with LHON at 6-month, 1-year, and 3-year follow-ups were 18.0 ± 19.2 (range 0-85.4), 19.9 ± 20.0 (range 0-85.4), and 20.7 ± 20.2 (range 0-85.4), and the differences were statistically significant (P < 0.001). VF-14 score at 6 months was significantly correlated with visual acuity of the better eye (P < 0.001) but not with age of onset (P = 0.43). Overall, the QoL improvement was significantly correlated with age of onset (P = 0.006) but not with visual acuity of the better eye (P = 0.134). Several abilities were significantly improved at the 1-year follow-up compared with the 6-month follow-up, including seeing steps, curbs, or stairs (P < 0.01), doing handiwork (P < 0.05), playing sports (P < 0.05), cooking (P < 0.01), and watching television (P < 0.05). When these scores were further compared between 1- and 3-year follow-ups, only scores for cooking (P < 0.05) and watching television (P < 0.05) were higher at the 3-year follow-up than that at the 1-year follow-up. No changes were found during the follow-up for reading small print, reading a newspaper or book, or reading signs.

CONCLUSIONS

Our results indicate that although most of our Chinese LHON patients with the G11778A mutation had permanent central visual loss, visual-related quality of life improved over time, especially in younger patients.