Abstract
Purpose: :
To evaluate a questionnaire determining subjective symptoms and quality of vision in refractive surgery patients with regard to reliability and validity.
Methods: :
40 ametropic subjects and 40 patients 1 month after uneventful LASIK completed the questionnaire at two consecutive days. The values were marked on a visual analog scale from 0 ("perfect"/"no symptom") - 100 ("extremely poor"/"maximal symptom intensity"). The questionnaire requested, for both eyes separately and for three different lighting conditions (photopic, high-mesopic and low-mesopic) the self rated quality of vision (SQV) and the intensity of the symptoms "glare", "halos", "starbursts", "blurred vision", "ghosting". The repeatability of the individual items was analyzed with Bland Altman analysis. The impact of individual symptoms on the SQV item was checked with the multiple regression analysis.
Results: :
The coefficient of repeatability (COR) of the group of the ametopics for the SQV item was 9.5 under photopic conditions (high-mesopic: 12.5, low-mesopic: 15.5). The average COR of the symptom scores was 13 8±5 (photopic), 14 1±6 (high-mesopic) and 15 4±5 (low-mesopic). On the contrary, in the LASIK group the COR values for both the SQV item (photopic: 24.2, high-mesopic: 15.5 and low-mesopic 13.5) and for the symptom scrores (photopic: 25 0±10, high-mesopic: 19 3±8 and low -mesopic 22 2±6) were higher. The symptom scores affected the SOQ of the ameotropics only moderately (adjusted R2 photopic: 0.68, high-mesopic: 0.38, low-mesopic 0.50) while the SOQ of the LASIK-group could largely be explained by the queried symptoms (adjusted R2 photopic: 0.85, high-mesopic: 0.91, low-mesopic 0.72).
Conclusions: :
The scores collected by the questionnaire could be obtained with a satisfactory repeatability. The Selection of the queried symptoms appears to be valid to describe the overall subjective quality of vision.
Keywords: refractive surgery: optical quality • quality of life