University of Edinburgh
 

Down's syndrome: vision, visual problems and visual assessment

Presented on 15 May 2008

J. Margaret Woodhouse, Cardiff University

Mohammad Al-Bagdady, Nathan Bromham, Mary Cregg,
Ping Ji, Ffion John, Julie-Anne Little, Julie McClelland,
Val Pakeman, Kathryn J. Saunders, Ruth Stewart

Accommodation

Accommodation - near focusing

near focusing

Prescribing for hypermetropia (long sight)

  • Most typical children have a small amount of long sight
  • Most children overcome long sight by active focusing

If accommodation is defective

  • Should we prescribe for smaller amounts of hypermetropia?

In our current study group, 76% of children with Down's syndrome have poor focusing for near targets.

  • Children have a focusing error even when they wear glasses for long or short sight.
  • Near tasks are blurred for most children.
  • It is not possible to predict which children have poor focusing
    - All children should be tested

Bifocal spectacle trial

Two groups (17 pairs of children; all of whom under-accommodate)
matched for:

  • age
  • cognitive ability
  • type of school
  • members of the cohort /new recruits
  • type of refractive error
  • current use of spectacles

Bifocal group – given specs with a +2.50D add (for use in school only) and had single vision specs for home.

Control group - had new 'single vision' specs for school use and kept their current specs at home.

Results

  • Excellent co-operation from all schools, teachers and classroom aides.
  • Positive response from children in both groups to new glasses, and compliance good.

results

  • FOUR children wore their bifocals at home as well as at school
    - in 3 cases parents requested this
    - in 1 case the child refused to remove the bifocals at the end of the school day!

Accommodation

At the outset there was no difference in the accommodation between the two groups.

accommodation

accommodation

Outcomes of trial

  • Children in the bifocal group accommodated more accurately
  • Teachers reported better concentration and writing skills in the children wearing bifocals

Stewart, RE, Woodhouse, JM & Trojanowska, LD (2005) Ophthalmic and Physiological Optics 25 (6), 514-522.

Prescribing guidelines

We use straight-topped D-28 bifocals, fitted with the segment top at, or just below, pupil centre. The fit is critical.

Bifocal wear

  • The children use their bifocals very successfully
  • We begin with bifocals for school use only
  • Most children choose to wear their bifocals full-time
  • Even (the few) children who are reluctant to wear ordinary specs will wear bifocals happily

bifocal use

Bifocal wear may be temporary

  • Out of 41 children prescribed bifocals so far 22 have improved their focusing over the top of the bifocal
  • 13 of these 22 (that is, 31% of all of the children) now accommodate accurately and have returned to ordinary glasses

Maximise vision by

  • Ensuring regular eye examinations
  • Examinations MUST include accommodation
  • Correcting defects with spectacles, including bifocals