Aniseikonia: A Potential Barrier To Neural Plasticity

Aims: Aniseikonia represents a potential barrier to neuroplasticity, which may limit visual outcomes in children with anisometropic amblyopia. Full refractive correction is the initial treatment for amblyopia, which corrects image focus, but image size differences are often neglected. We aimed to identify the potential impact of aniseikonia by investigating current treatment outcomes in New Zealand children, measuring aniseikonia subjectively in amblyopia, and through incorporating aniseikonia correction at the time of initial treatment for anisometropic amblyopia in children. Methods: A retrospective chart review of children that failed preschool vision screening investigated causes of visual impairment and treatment outcomes of children seen in hospital eye services (HES). A cross-sectional study used clinical and psychophysical methods to quantify aniseikonia in isometropia, anisometropia and amblyopia. A prospective double-masked randomised clinical trial (Measuring aniseikonia & investigating neuroplasticity and image factors in amblyopia (MAGNIFY) study) compared the effectiveness of aniseikonia-correcting lenses to standard spectacle lenses for the treatment of anisometropic amblyopia. A novel, compact spectacle wear monitor was designed and tested to be used by children enrolled in the MAGNIFY study. Results: Children referred to HES following a failed B4 School vision screening test mostly commonly had reduced visual acuity due to refractive error, and anisometropia was the most common cause of amblyopia. Treatment disengagement was found to be higher-than-expected in Māori and Pacifica children highlighting potential health service-related inequalities. Subjective aniseikonia can successfully be measured in anisometropic amblyopia with greater amounts found compared to those with anisometropia alone. The ongoing MAGNIFY study found, at the mid-term analysis, that distance visual acuity of all amblyopic eyes improved by 4 lines and stereoacuity improved by 2 octaves after 15 weeks of spectacle wear. Optical treatment was well tolerated, and adherence was high. However, broken or damaged spectacles can disrupt treatment and be a burden for families. The SpecsOn monitor was found to measure spectacle wear accurately and reliably. Conclusion: Aniseikonia frequently occurs in anisometropia and clinical assessment of subjective aniseikonia in anisometropic amblyopia is possible. Optical treatment is a safe and acceptable treatment for anisometropia and amblyopia.

Name thesis:degree_name

PhD

Level thesis:degree_level

Doctoral

Discipline thesis:degree_discipline

Optometry and Vision Science

Grantor dc:publisher

ResearchSpace@Auckland

Year dc:date.issued

2022

Author dc:creator

• South, Jayshree

Advisors dc:contributor.advisor

• Black, Joanna
• Collins, Andrew
• Gao, Tina

Statement dc:rights

• Items in ResearchSpace are protected by copyright, with all rights reserved, unless otherwise indicated.

Licence dc:rights.uri

• https://researchspace.auckland.ac.nz/docs/uoa-docs/rights.htm

Handle dc:identifier.uri

https://hdl.handle.net/2292/62153

OAI identifier oai:identifier

oai:researchspace.auckland.ac.nz:2292/62153