title: Randomised controlled trial of treatment of unilateral visual impairment detected at preschool vision screening.
abstract: OBJECTIVE
  To test the efficacy of treatment for unilateral visual loss detected by preschool vision screening and the extent to which effectiveness varies with initial severity.
  
  
  METHODS
  Randomised controlled trial of full treatment with glasses and patching, if required, compared with glasses only or no treatment. Masked assessment of best corrected acuity after one year of follow up.
  
  
  METHODS
  Eight UK eye departments.
  
  
  METHODS
  177 children aged 3-5 years with mild to moderate unilateral impairment of acuity (6/9 to 6/36) detected by screening.
  
  
  RESULTS
  Children in the full and glasses treatment groups had incrementally better visual acuity at follow up than children who received no treatment, but the mean treatment effect between full and no treatment was equivalent to only one line on a Snellen chart (0.11 log units; 95% confidence interval 0.050 to 0.171; P < 0.0001). The effects of treatment depended on initial acuity: full treatment showed a substantial effect in the moderate acuity group (6/36 to 6/18 at recruitment) and no significant effect in the mild acuity group (6/9 to 6/12 at recruitment) (P = 0.006 for linear regression interaction term). For 64 children with moderate acuity loss the treatment effect was 0.20 log units, equivalent to one to two lines on a Snellen chart. When all children had received treatment, six months after the end of the trial, there was no significant difference in acuity between the groups.
  
  
  CONCLUSIONS
  Treatment is worth while in children with the poorest acuity, but in children with mild (6/9 to 6/12) unilateral acuity loss there was little benefit. Delay in treatment until the age of 5 did not seem to influence effectiveness.
authors.affiliation: Department of Ophthalmology, School of Neurobiology, Neurology and Psychiatry, University of Newcastle upon Tyne, Newcastle NE2 4HH. M.P.Clarke@ncl.ac.uk
authors.forename: M P
authors.initials: MP
authors.lastname: Clarke
authors.forename: C M
authors.initials: CM
authors.lastname: Wright
authors.forename: S
authors.initials: S
authors.lastname: Hrisos
authors.forename: J D
authors.initials: JD
authors.lastname: Anderson
authors.forename: J
authors.initials: J
authors.lastname: Henderson
authors.forename: S R
authors.initials: SR
authors.lastname: Richardson
mesh_terms: D000550:Amblyopia / Q000175:diagnosis / Q000503:physiopathology / Q000628:therapy*; D001458:Bandages; D002675:Child, Preschool; D005139:Eyeglasses; D005500:Follow-Up Studies; D006801:Humans; D010349:Patient Compliance; D016037:Single-Blind Method; D016896:Treatment Outcome; D015351:Vision Screening; D014792:Visual Acuity / Q000502:physiology