Study designs of evaluations included in the review
Prospective controlled trials of treatments (with or without randomisation), for any of the target conditions were eligible for inclusion in the review.
Controlled trials, observational studies and audits of screening programmes for any of the target conditions were eligible for inclusion in the review.
Specific interventions included in the review
Studies evaluating treatment and screening for 3 target conditions: amblyopia, refractive errors, and squints which are not cosmetically obvious, were eligible for inclusion in the review.
Treatment interventions used in included studies were: CAM vision stimulator; conventional orthoptic treatment; levodopa or carbidopa; prism adaptation; occlusion; surgery or placebo.
Screening tests used in included studies were: appearance of eyes; head posture; cover test; ocular movements; convergence; 20D base out prism; stereotest (randot circles, Frisby, Lang, TNO, or Wirt Fly and pictures of animals); visual acuity (Sheridan-Gardiner opotypes, Snellen, letter matching, Kaye pictures, or Marquez-Bostrom's hooks). Rerrefal criteria (i.e. positive screening test thresholds) used in included studies were: visual acuity (6/9 or less either eye, 6/12 or less either eye, 5/6 or less either eye, less than 6/6 either eye, greater than one line difference between eyes); eso/exophoria greater than 10D or 8D base out/in near/distance; abnormal response to prism; inward/outward deviation on cover test; manifest strabismus; nystagmus; heterotropia; abnormality of ocular muscle balance; convergence insufficiency 8cm or worse; abnormal appearance of eyes; facial asymmetry; abnormal head posture; ptosis; poor fusion or binocular vision; negative response to stereotest.
Reference standard test against which the new test was compared
No inclusion criteria were specified with respect to any reference standard test.
Participants included in the review
Studies of children aged 3 to 7 years treated for any of the target Conditions, and screening studies of children aged 3 to 4 years were eligible for inclusion in the review. Studies that focused on children with both severe disabilities and visual defects were excluded.
Outcomes assessed in the review
Studies using the following outcome measures were eligible for inclusion in the review:
Treatment: visual outcomes, visual complications associated with surgery, spectacle use, disability, patient perceived outcomes, and other side-effects.
Screening: uptake rates, referral rates, diagnostic yield, positive and negative predictive values (PPV and NPV, respectively), sensitivity, specificity, costs, visual outcomes, and patient perceived health outcomes. Outcome measures relating to diagnostic accuracy were calculated (in all primary studies identified) using retrospective analysis of hospital case records to determine the final diagnosis.
How were decisions on the relevance of primary studies made?
The authors do not state how the papers were selected for review, or how many of the reviewers performed the selection.