Validation of the vision quality of life-time survey: comparison with the convergence insufficiency symptom survey.

CLINICAL RELEVANCE: Assessing the duration patients can sustain visual tasks before symptom onset provides clinically relevant insight into functional vision and visual discomfort, supporting diagnosis, monitoring, and management of binocular and accommodative disorders.

BACKGROUND

The Vision Quality of Life with Time (VisQuaL-T) questionnaire quantifies how long individuals can perform visual tasks before symptom onset, providing a measure of vision-related quality of life. Although validated in English, it had not been evaluated in Hebrew. This study aimed to translate and validate the VisQuaL-T in Hebrew, assess its test-retest reliability, and examine its concurrent validity relative to the Convergence Insufficiency Symptom Survey (CISS).

METHODS

Fifty healthy participants (mean age 23.2 ± 6.2 years; 62% female; range 12-34) with best-corrected Snellen visual acuity ≤6/6 (0.0 LogMAR) and stereopsis ≤250 arcseconds were recruited. Participants completed the Hebrew VisQuaL-T (10 items) twice, 14 days apart, and the CISS (15 items) once. Translation followed a forward-backward protocol. Non-parametric analyses were applied due to non-normally distributed data. Reliability was assessed using the Wilcoxon Signed-Rank Test, Bland-Altman analysis, and Spearman correlation. Internal consistency was evaluated using Cronbach's alpha and convergent validity with the CISS using Spearman's rho.

RESULTS

Mean VisQuaL-T scores at the two administrations were 2.48 ± 0.50 and 2.39 ± 0.56 (p = 0.10). Agreement between administrations was high, with strong test-retest reliability (Rs = 0.80, p < 0.001), except for item 6. Scores did not differ significantly from English normative data (p = 0.65). Internal consistency was high for all questionnaires (Cronbach's α = 0.80-0.85). A moderate negative correlation was observed between VisQuaL-T and CISS scores (Rs = -0.42, p < 0.001). No significant associations were found with age or gender.

CONCLUSIONS

The Hebrew VisQuaL-T demonstrates strong reliability, internal consistency, and concurrent validity, supporting its use as a clinical and research instrument for assessing vision-related quality of life in Hebrew-speaking populations.