Delphi methodology for symptomatology associated with visual dysfunctions

Evaluation and application of a Chinese version symptom questionnaire for visual dysfunctions (CSQVD) in school-age children

Objective

To develop and evaluate a Chinese version of the Symptom Questionnaire for Visual Dysfunctions (CSQVD) to quantify visual dysfunction symptoms in school-age children with various eye diseases, and to explore the relationship between ophthalmological disorders and visual dysfunction symptoms.

Methods

Following standard scale adaptation procedures, the Symptom Questionnaire for Visual Dysfunctions (SQVD) was translated into Chinese (CSQVD). We employed random sampling to survey 198 outpatients aged 7-18 to assess the psychometric properties of the CSQVD. Using the reliable and validated questionnaire, we evaluated the determinants of visual dysfunction symptoms among 406 school-age patients at an eye center. The CSQVD scores were correlated with demographic and clinical variables, including gender, age, eye position, refractive power, and best-corrected visual acuity. Univariate analysis identified potential risk factors, followed by binary logistic regression and multiple linear regression analysis on factors with a P-value <0.05.

Results

The CSQVD scale's critical ratio (CR) values ranged from 6.028 to 10.604. The Cronbach's Alpha coefficient was 0.779, and Spearman-Brown split-half reliability was also 0.779. The I-CVI varied from 0.83 to 1.000, the S-CVI/Ave was 0.857, and the KMO value was 0.821. Multifactorial regression analysis indicated that high myopia (OR ​= ​5.744, 95% CI [1.632, 20.218], P ​= ​0.006) and amblyopia (OR ​= ​9.302, 95% CI [1.878, 46.058], P ​= ​0.006) were significant predictors of CSQVD symptoms. Multiple linear regression analysis showed that BCVA of amblyopic eyes (B ​= ​-5.052, 95% CI [-7.779, 2.325], P ​= ​0.000) and SE power (B ​= ​-0.234, 95% CI [-0.375, 0.205], P ​= ​0.001) significantly affected the CSQVD scale scores.

Conclusions

The Chinese version of the SQVD scale (CSQVD) demonstrates good feasibility, discriminatory power, validity, and reliability in assessing Chinese school-aged children. Furthermore, those who have severe myopia and amblyopia reported more visual dysfunction symptoms.

Assessing the role of visual dysfunctions in the association between visual symptomatology and the use of digital devices

PURPOSE

To evaluate the association between visual symptoms and use of digital devices considering the presence of visual dysfunctions.

METHODS

An optometric examination was conducted in a clinical sample of 346 patients to diagnose any type of visual anomaly. Visual symptoms were collected using the validated SQVD questionnaire. A threshold of 6 hours per day was used to quantify the effects of digital device usage and patients were divided into two groups: under and above of 35 years old. A multivariate logistic regression was employed to investigate the association between digital device use and symptoms, with visual dysfunctions considered as a confounding variable. Crude and the adjusted odds ratio (OR) were calculated for each variable.

RESULTS

57.02 % of the subjects reported visual symptoms, and 65.02% exhibited some form of visual dysfunction. For patients under 35 years old, an association was found between having visual symptoms and digital device use (OR = 2.10, p = 0.01). However, after adjusting for visual dysfunctions, this association disappeared (OR = 1.44, p = 0.27) and the association was instead between symptoms and refractive dysfunction (OR = 6.52, p < 0.001), accommodative (OR = 10.47, p < 0.001), binocular (OR = 6.68, p < 0.001) and accommodative plus binocular dysfunctions (OR = 46.84, p < 0.001). Among patients over 35 years old, no association was found between symptoms and the use of digital devices (OR = 1.27, p = 0.49) but there was an association between symptoms and refractive dysfunction (OR = 3.54, p = 0.001).

CONCLUSIONS

Visual symptoms are not dependent on the duration of digital device use but rather on the presence of any type of visual dysfunction: refractive, accommodative and/or binocular one, which should be diagnosed.

Validation of the Symptom Questionnaire for Visual Dysfunctions (SQVD): A Questionnaire to Evaluate Symptoms of any Type of Visual Dysfunctions

Purpose

To assess psychometric properties of the Symptom Questionnaire for Visual Dysfunctions (SQVD) questionnaire, including accuracy, validity, and reliability, in a clinical sample of patients having any type of visual dysfunction.

Methods

A clinical sample of 306 patients self-administered the SQVD. Rasch analysis was performed to analyze the functionality of the response categories, fit statistics, differential item functioning (DIF), person and item reliability, targeting, local dependency, unidimensionality, and transformation table. Accuracy was assessed by means of receiver operating characteristic (ROC) curves, using symptoms reported in each patient's clinical record as the gold standard for classifying patients with and without symptoms. The concurrent validity, known group validity, and test–retest reliability (repeatability, using the intraclass correlation coefficient [ICC]) were also examined.

Results

SQVD showed orderly category responses. The 14 items fit the Rasch model without significant DIF for gender, presbyopia, and dysfunctions. Person and item reliabilities were 0.81 and 0.85, respectively. Targeting was –1.49 logits. Yen's Q3 statistic showed no local dependency. SQVD was unidimensional (first contrast of the residual = 1.852 eigenvalue with a variance explained by measures of 52.23%). The area under the ROC curve was 0.836 (95% confidence interval [CI], 0.792–0.879) with a cutoff of ≥6 showing good accuracy (sensitivity = 0.759; specificity = 0.783). SQVD showed good concurrent and known group validity and high repeatability (ICC, 0.857; 95% CI, 0.710–0.933) when administered twice 1 week apart.

Conclusions

SQVD has shown good psychometric properties. It can be considered an accurate, valid, and reliable questionnaire to detect visual symptoms related to any type of refractive, accommodative, and binocular dysfunction.

Translational Relevance

SQVD may be used for diagnostic purposes, as it can accurately detect symptoms related to any sort of visual dysfunction. It may also be useful to monitor the treatment outcomes of these conditions.

Rasch analysis for development and reduction of Symptom Questionnaire for Visual Dysfunctions (SQVD)

To develop the Symptom Questionnaire for Visual Dysfunctions (SQVD) and to perform a psychometric analysis using Rasch method to obtain an instrument which allows to detect the presence and frequency of visual symptoms related to any visual dysfunction. A pilot version of 33 items was carried out on a sample of 125 patients from an optometric clinic. Rasch model (using Andrich Rating Scale Model) was applied to investigate the category probability curves and Andrich thresholds, infit and outfit mean square, local dependency using Yen's Q3 statistic, Differential item functioning (DIF) for gender and presbyopia, person and item reliability, unidimensionality, targeting and ordinal to interval conversion table. Category probability curves suggested to collapse a response category. Rasch analysis reduced the questionnaire from 33 to 14 items. The final SQVD showed that 14 items fit to the model without local dependency and no significant DIF for gender and presbyopia. Person reliability was satisfactory (0.81). The first contrast of the residual was 1.908 eigenvalue, showing unidimensionality and targeting was - 1.59 logits. In general, the SQVD is a well-structured tool which shows that data adequately fit the Rasch model, with adequate psychometric properties, making it a reliable and valid instrument to measure visual symptoms.