Visual Functioning in Adults with Idiopathic Infantile Nystagmus Syndrome (IINS)
Aditi Das, FRCOphth; Ana Quartilho MSc; Kelly Mackenzie MSc; Catey Bunce PhD; Gary Rubin PhD;
Gillian G. Adams, FRCOphth; Annegret Dahlmann-Noor, PhD, FRCOphth; Maria Theodorou, PhD, FRCOphth
Paediatric Ophthalmology and Strabismus, Moorfields Eye Hospital
Introduction: Idiopathic Infantile Nystagmus syndrome is associated with visual impairment, strabismus and anomalous head postures. Recent publications demonstrate the negative impact of IINS on quality of life (QoL). Our study examines visual functioning of adults with IINS using the National Eye Institute Visual Function Questionairre-25 (NEI-VFQ-25).
Methods: 38 patients were recruited into the study, which formed part of a randomised control trial examining the effects of contact lenses on IINS. Participants underwent detailed clinical examination and investigations including eye movement recordings. Patients were requested to complete the self-administered NEI-VFQ-25 at baseline.
Results: 35/38 (92%) participants completed the NEI-VFQ-25. Mean age was 35.1 years (range 16-64). Median overall NEI-VFQ score was 69, and interquartile range (IQR) was 56-76. IINS patients had specifically low scores in the categories of mental health (median 50, IQR 25-63), role limitations and dependency (median 50, IQR 25-75 and median 58, IQR 50-75 respectively). 26/35 (74%) participants did not drive, either due to sub-normal vision or lack of confidence.
Discussion: IINS can considerably impact QoL, without necessarily causing markedly reduced visual acuity. Our patients reported lowest VFQ-25 scores in the domains of mental health, wellbeing and visual functioning in driving. The VFQ-25 provides more insight into the effect of IINS on QoL than objective measures including high contrast Snellen or LogMAR visual acuity.
Conclusion: IINS can negatively impact QoL. Existing clinical methods may underestimate the true effect of IINS on everyday life and should be used in conjunction with quality of life surveys including the NEI-VFQ-25.
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