Abstract
Purpose: CVI, the commonest cause of visual loss in children in the developed world with prevalence rising worldwide; manifests with variable VA loss and diverse HVFDs such as difficulty with motion perception and visual environmental clutter. Visual behaviorisms suggestive of HVFDs even in CVI children with good VA, are oberved by parents and teachers with adverse effects on daily activities at school and home. Good VA in CVI children often precludes further investigation for HVFDs. We investigated HVFDs in children with CVI and good VA through structured history-taking with HVF Question Inventory (HVFQI) and develop an abbreviated QI for rapid screening.
Methods: Parents of 33 children with CVI (7.0 +/- 2.7 yrs.) with good VA (>/=0.2 LogMar) and 111 typical children (8.7+/-2.8 yrs.) participated. CVI diagnosis was based on integrated assessment of history, eye and neurologic examination and brain imaging. Parents responded to the 51 questions choosing from a 5-point Likert scale: Never, Rarely, Sometimes, Often, Always. ‘Not Applicable’ (NA) option was available. Initial analysis tested the ability of HVFQI to differentiate between CVI and typicals by calculating average score for each question adjusted for NA responses. Next, the questions that offered best discriminability as a screening tool were determined by scoring across a series of binary divisions along the Likert scale followed by area- under-curve (AUC) analysis for each question and each binary-scoring method.
Results: Children with CVI scored significantly higher than typical children in overall scores and in all binary scoring methods (p-values < 0.001). Three binary-scoring methods gave us the highest AUC values (>0.87) and revealed 11 questions that contributed most to an affirmative result for presence of HVFD. These related to problems with clutter, lower visual field, motion perception and multi-tasking and termed HVFQI-Top11.