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P-12 Contrast-modulated crowded acuity and interocular differences in amblyopic children
  1. Louisa A Haine1,
  2. Monika A Formankiewicz1,
  3. Sarah JH Lalor1,
  4. Akash S Chima1,
  5. Sarah J Waugh1,2
  1. 1Anglia Ruskin University, Cambridge, UK
  2. 2University of Huddersfield, Huddersfield, UK

Abstract

Introduction Amblyopia is a neurodevelopmental disorder characterised by deficits in visual acuity (VA). Amblyopes with strabismus are more sensitive to visual crowding so it is important to use crowded VA tests to enhance interocular differences (IOD), such as the ‘Enhanced Cambridge Crowding Test’ (ECC). Research in adults has indicated that crowding magnitude is increased when contrast-modulated noise (CM) stimuli are used compared to luminance-generated stimuli. CM stimuli may therefore be advantageous to use to detect amblyopia in children.

Aims This study aimed to establish whether an ECC test presented with CM optotypes (CM-ECC) offers greater sensitivity for paediatric amblyopia detection than the Sonksen logMAR Test (SLT), a standard hospital test.

Methods Monocular VA thresholds were examined in groups of children: a control group (n=24) and amblyopic groups (n=43; n=22 anisometropic amblyopes, n=21 strabismic/mixed amblyopes), aged 3–11 years. VA thresholds for both ‘crowded’ and isolated luminance (L) and CM optotypes were obtained from self-paced, interleaved, two-down, one-up staircases combined with a four-alternative, forced-choice (4AFC) paradigm. VA was also obtained according to SLT instructions.

Results While the CM-ECC yielded significantly larger (logMAR) acuities (P<.001), neither crowding magnitudes (P=.635) nor IODs (P=.306) were different from those obtained with SLT.

Conclusion As a paediatric visual screening tool, the CM-ECC provides no additional diagnostic benefit over the SLT.

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