Pharmacological treatment of infantile nystagmus and assessing the impact from the patient's perspective

• Main Author: McLean, Rebecca Jane
• Other Authors: Proudlock, Frank; Gottlob, Irene
• Published: University of Leicester 2015
• Subjects: 616.1
• Online Access: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.657563

Background : Nystagmus is an involuntary to and fro movement of the eyes that can be infantile or acquired and causes reduced vision. Little literature exists documenting how nystagmus affects quality of life and treatment options are largely empirical with very few randomised controlled trials. Methods : Semi-structured interviews of 21 participants were analysed using a constant comparison approach based upon grounded theory. A randomised, triple masked, controlled trial of gabapentin and memantine was performed on 66 participants with infantile nystagmus. Outcome measures were 25% improvement in visual acuity (primary outcome), 25% improvement in eye movement, absolute change in visual function and eye movement and descriptive analysis of nystagmus waveforms responding to treatment. Results : Analysis of participants’ accounts revealed six domains of living that were adversely affected by nystagmus: visual function, restriction of movement (both physical and social), standing out/not fitting in, feelings about the inner self, negativity with regards to the future and relationships. Cosmetic appearance of nystagmus was, for the first time, described as being problematic and additional to other categories was an overarching and universal distress arising from nystagmus affecting every aspect of everyday life. Gabapentin and memantine did not improve visual function as a 25% improvement or when assessing the absolute differences. In contrast null region nystagmus intensity and NAFX were significantly different for treatment as gabapentin reduced intensity and improved NAFX by 25%. For absolute differences in null region nystagmus intensity gabapentin was also significant. Pendular waveforms prevalently appeared in those participants responding to gabapentin. Baseline measurements were often a predictor for success of treatment. Both gabapentin and memantine were both reasonably well tolerated. Conclusion : Interviews revealed universally negative experiences of living with nystagmus that are previously unreported. Gabapentin, and not memantine, significantly reduces eye movement in infantile nystagmus but does not improve visual function.