The perceptual effects of crowding in amblyopic and developing vision
Research type
Research Study
Full title
The perceptual effects of crowding in amblyopic and developing vision
IRAS ID
170337
Contact name
John A Greenwood
Contact email
Sponsor organisation
University College London
Clinicaltrials.gov Identifier
Z6364106/2015/03/174, Data Protection Registration
Duration of Study in the UK
1 years, 0 months, 0 days
Research summary
Amblyopia ('lazy eye') is a developmental disorder affecting ~3% of the population, and the most common cause of childhood visual impairment. It is characterised by reduced vision in one eye that persists despite optical correction. When amblyopia is associated with strabismus (ocular misalignment), vision is further affected by crowding: objects that are otherwise visible in isolation become difficult to recognise in clutter. This interference has been reported to persist in amblyopic vision even after treatment. However, we understand very little about its underlying mechanism.
Crowding is also elevated in the central vision of normally developing children, up to at least 12 years of age. This has clear functional consequences, given the correlation between crowding and reading ability. The processes that cause this elevation, and its recession over time are unclear.
The goal of this project is to gain a better understanding of amblyopic and developmental crowding by examining the effect of these forms of crowding on the appearance of objects (e.g. letters). We will test two groups (n=30 each, 3-9 years of age): children with strabismic amblyopia and unaffected children. The experimental tests will be carried out in the Richard Desmond Children's Eye Centre, and involve children playing a specially designed videogame with a 'VacMan' character and distractor 'ghosts' for approximately 30 minutes.
This 12-month project (funded by the UCL Impact Award, the Moorfields Special Trustees and the Medical Research Council) will have several important outcomes. First, we will gain an insight to the mechanisms underlying amblyopic visual deficits. Second, we will determine whether amblyopic and developmental forms of crowding share the same mechanisms as crowding in the normal adult periphery. An increased understanding of the mechanisms underlying amblyopic crowding and their relation to processes in the unaffected visual system will allow a more principled approach to the treatment of this deficit.
REC name
East Midlands - Leicester Central Research Ethics Committee
REC reference
15/EM/0167
Date of REC Opinion
10 Apr 2015
REC opinion
Favourable Opinion