With a prevalence of 2–5%, amblyopia is the most common vision deficit in children in the UK and the second most common cause of functional low vision in children in low-income countries. Pubmed, Cochrane library and clinical trial registries (clinicaltrials.gov, ISRCTN, UKCRN portfolio database). Screening and treatment at the age of 4–5 years are cost efficient and clinically effective. Optical treatment (glasses) alone can improve visual acuity, with residual amblyopia treated by part-time occlusion or pharmacological blurring of the better-seeing eye. Treatment after the end of the conventional ‘critical period’ can improve vision, but in strabismic amblyopia carries a low risk of double vision. It is not clear whether earlier vision screening would be cost efficient and associated with better outcomes. Optimization of treatment by individualized patching regimes or early start of occlusion, and novel binocular treatment approaches may enhance adherence to treatment, provide better outcomes and shorten treatment duration. Binocular treatments for amblyopia. Impact of amblyopia on education and quality of life; optimal screening timing and tests; optimal administration of conventional treatments; development of child-friendly, effective and safe binocular treatments.

Purpose: Amblyopia is a common developmental visual impairment characterized by a substantial difference in acuity between the two eyes. Current monocular treatments, which promote use of the affected eye by occluding or blurring the fellow eye, improve acuity, but are hindered by poor compliance. Recently developed binocular treatments can produce rapid gains in visual function, thought to be as a result of reduced interocular suppression. We set out to develop an effective home-based binocular treatment system for amblyopia that would engage high levels of compliance but that would also allow us to assess the role of suppression in children's response to binocular treatment. Methods: Balanced binocular viewing therapy (BBV) involves daily viewing of dichoptic movies (with “visibility” matched across the two eyes) and gameplay (to monitor compliance and suppression). Twenty-two children (3–11 years) with anisometropic (n = 7; group 1) and strabismic or combined mechanism amblyopia (group 2; n = 6 and 9, respectively) completed the study. Groups 1 and 2 were treated for a maximum of 8 or 24 weeks, respectively. Results: The treatment elicited high levels of compliance (on average, 89.4% ± 24.2% of daily dose in 68.23% ± 12.2% of days on treatment) and led to a mean improvement in acuity of 0.27 logMAR (SD 0.22) for the amblyopic eye. Importantly, acuity gains were not correlated with a reduction in suppression. Conclusions: BBV is a binocular treatment for amblyopia that can be self-administered at home (with remote monitoring), producing rapid and substantial benefits that cannot be solely mediated by a reduction in interocular suppression.

Background/Aim: The COMPlog clinical visual acuity measuring system is being developed for both routine and research use. This study aimed to validate its performance in amblyopic children and both normal and diseased adults against the gold standard ETDRS chart and the E-ETDRS computerised acuity measurement algorithm. Method: Timed test and retest fully interpolated five letters per line logMAR visual acuity measurements were taken for 70 adults and 59 amblyopic children using the ETDRS chart and the COMPlog visual acuity measurement system. 39 of the adults also underwent computerised acuity testing using the E-ETDRS testing algorithm. The tested adults included normals as well as subjects with a range of ocular diseases. The methods of Bland and Altman were employed with test–retest variability (TRV) expressed as 95% confidence limits for agreement. Results: No significant bias was observed between the gold standard ETDRS acuity measurements and those taken with either COMPlog or E-ETDRS. TRVs of ±0.12 logMAR and ±0.10 logMAR were respectively found for COMPlog measurements in the amblyopic children and adult groups compared with ±0.12 logMAR for the ETDRS chart in both groups. The TRV of the E-ETDRS system was slightly greater at ±0.16 logMAR. Median testing times for COMPlog and ETDRS were 95 and 85 s and 66 and 56 s respectively in the paediatric and adult groups and 120 s for the E-ETDRS measurements on adults. Discussion: COMPlog measurements agree well with and are similarly reliable to the gold standard ETDRS chart with comparable test times. E-ETDRS algorithm measurements took approximately twice as long.

Purpose. During development, the presence of strabismus and anisometropia frequently leads to amblyopia, a visual disorder characterized by interocular acuity differences. Although additional deficits in contrast sensitivity, crowding (the impaired recognition of closely spaced objects), and stereoacuity are common, the relationship between these abilities is unclear. Methods. We measured the covariation between these four abilities in children 4 to 9 years of age (n = 72) with strabismus, anisometropia, or mixed strabismus/anisometropia, and unaffected controls. Children reported the orientation of a target (a modified “Pac-Man,” similar to Landolt-C stimuli) using four “ghosts” as references. Using a modified staircase procedure we measured threshold size (acuity), contrast detection, foveal crowding (the minimum separation between target and ghost-flankers supporting accurate identification), and stereoacuity (with random-dot stereogram ghosts). Results. Group averages revealed significant interocular differences (IODs) in acuity for all three clinical groups (0.2–0.3 log minutes), and significant crowding IODs for the strabismic and mixed groups (0.6 and 0.4°, respectively). Nonetheless, crowding IODs were correlated with acuity IODs in all four groups (r values between 0.43 and 0.59 and P < 0.05; P = 0.07 in the mixed group). Similarly, the occurrence of stereo-blindness (most common in strabismic and mixed groups) was associated with a significant increase in IODs for both acuity and crowding (each P < 0.05). No correlations were found with contrast detection. Conclusions. Our results demonstrate an association between IODs in acuity and crowding and, furthermore, between these IODs and the presence of stereo-vision. We suggest that the deficits derived from strabismus and anisometropia lay along a continuum with abilities observed during normal development.