Children with amblyopia read slower than their peers during binocular viewing. Ocular motor dysfunction typical of amblyopia may cause slow reading. It is unclear whether this is due to fixation instability or increased forward saccades. We examined whether removing the requirement of inter-word saccades helps children with amblyopia read at a similar rate as controls using a rapid serial visual presentation (RSVP) task. We also assessed whether reading rate was related to fixation instability. Children with amblyopia (n = 32) and control (n = 30) children ages 8-12 years silently read sentences presented in RSVP (single word presentation at screen center) during binocular viewing. Exposure time per sentence changed with a 2 - down 1 - up staircase to obtain reading speed thresholds (log words/minute [WPM]). Eye movements were tracked to determine fellow eye (FE) and amblyopic eye (AE) fixation stability during RSVP reading. Children with amblyopia read slower than controls (2.75 ± 0.47 log WPM vs 3.06 ± 0.40 log WPM), and had increased AE fixation instability (0.21 ± 0.39 log deg2 vs - 0.20 ± 0.18 log deg2) and increased FE fixation instability (-0.03 ± 0.34 log deg2 vs - 0.20 ± 0.15 log deg2) during RSVP reading. Reading rate in amblyopic children with good FE stability (n = 11) did not differ from controls and was faster than those with poor FE stability (n = 21). Children with poor FE stability read slower than controls. Removing the need for inter-word saccades (i.e., RSVP reading) did not help children with amblyopia read at control speeds. Our data support FE fixation instability as a source of slow reading in amblyopia.

Background We developed and tested a dichoptic treatment designed for younger children that can be viewed freely and involves a dichoptic manipulation of a popular animation series that enables contrast-rebalancing without disrupting fusion. Our aim was to assess whether this novel amblyopia treatment is superior to patching in children aged 3-5 years. Methods A total of 34 children with amblyopia were randomly assigned to contrast-rebalanced dichoptic cartoons (4 hours/week) or patching (14 hours/week) for 2 weeks. Children in the cartoon group continued watching cartoons for an additional 2 weeks. Designed to target the youngest and most treatable children, the dichoptic cartoons presented the entire scene to the amblyopic eye at 100% contrast, while the fellow eye view was presented at reduced contrast with the main character omitted. Best-corrected visual acuity (BCVA), stereoacuity, suppression, and manual dexterity were measured at each visit. Results After 2 weeks, improvement in amblyopic eye BCVA was greater for dichoptic treatment than for patching, with a mean improvement of 0.11 ± 0.08 versus 0.06 ± 0.09 logMAR, respectively (P = 0.04). Stereoacuity, suppression, and manual dexterity did not improve significantly more in the dichoptic group than the patching group at 2 weeks. After 4 weeks of dichoptic cartoon treatment, mean visual acuity improvement in the dichoptic group was 0.16 logMAR (95% CI, 0.10-0.21). Conclusions In our study cohort, a contrast-rebalanced dichoptic cartoon was more effective than patching in treating childhood amblyopia after 2 weeks. Dichoptic cartoons that rebalance contrast to overcome suppression provide an additional treatment option for amblyopia in young children.

SIGNIFICANCE:Amblyopic children read 25% slower than their peers during binocular silent reading.PURPOSE:We compared binocular reading to fellow eye reading to determine whether slow reading in amblyopic children is due to binocular inhibition; that is, the amblyopic eye is interfering during binocular reading.METHODS:In a cross-sectional study, 38 children with amblyopia and 36 age-similar control children who completed grades 1 to 6 were enrolled. Children silently read grade-appropriate paragraphs during binocular reading and fellow eye reading while wearing ReadAlyzer eye-tracking goggles (Compevo AB, Stockholm, Sweden). Reading rate, number of forward saccades, number of regressive saccades, and fixation duration were analyzed between groups and between viewing conditions. We also examined whether sensory factors (amblyopia severity, stereoacuity, suppression) were related to slow reading.RESULTS:For amblyopic children, binocular reading versus fellow eye reading did not differ for reading rate (176 ± 60 vs. 173 ± 53 words per minute, P = .69), number of forward saccades (104 ± 35 vs. 97 ± 33 saccades/100 words, P = .18), number of regressive saccades (21 ± 15 vs. 22 ± 13 saccades/100 words, P = .75), or fixation duration (0.31 ± 0.06 vs. 0.32 ± 0.07 seconds, P = .44). As expected, amblyopic children had a slower reading rate and more forward saccades than control children during binocular reading and fellow eye reading. Slow reading was not related to any sensory factors.CONCLUSIONS:Binocular reading did not differ from fellow eye reading in amblyopic children. Thus, binocular inhibition is unlikely to play a role in slow binocular reading and is instead a fellow eye deficit that emerges from a disruption in binocular visual experience during development.

Poor control of intermittent exotropia may be used as an indication for surgery. However, control fluctuates during the day and from day to day. The standardized triple office control score (mean of three scores on a 6-point ordinal scale) is representative of repeated assessments throughout the day, but lacks validation against an objective measure of eye movements. We report the agreement between the triple office control score measured by the referring eyecare professional and lab-measured vergence instability using an EyeLink video eye tracker. Near and distance triple office control scores were moderately correlated with vergence instability. Near, but not distance, triple office control score was moderately correlated with the percentage of time intermittent exotropia was manifest during EyeLink recording. Larger triple office control scores for intermittent exotropia provide a meaningful description of larger vergence instability, supporting its use in clinical decisions and as a measure in clinical trials.

Contrast-rebalanced dichoptic movies have been shown to be an effective binocular treatment for amblyopia in the laboratory. Yet, at-home therapy is a more practical approach. In a randomized clinical trial, we compared dichoptic movies, streamed at-home on a handheld 3D-enabled game console, versus patching as amblyopia treatment. Sixty-five amblyopic children (3–7 years; 20/32–125) were randomly assigned to one of two parallel arms, binocular treatment (3 movies/week) or patching (14 h/week). The primary outcome, change in best corrected visual acuity (BCVA) at the 2-week visit was completed by 28 and 30, respectively. After the primary outcome, both groups of children had the option to complete up to 6 weeks of binocular treatment. At the 2-week primary outcome visit, BCVA had improved in the movie (0.07 ± 0.02 logMAR; p < .001) and patching (0.06 ± 0.01 logMAR; p < 0.001) groups. There was no significant difference between groups (CI 95 %: − 0.02 to 0.04; p = .48). Visual acuity improved in both groups with binocular treatment up to 6 weeks (0.15 and 0.18 logMAR improvement, respectively). This novel, at-home, binocular movie treatment improved amblyopic eye BCVA after 2 weeks (similar to patching), with additional improvement up to 6 weeks. Repeated binocular visual experience with contrast-rebalanced binocular movies provides an additional treatment option for amblyopia. Clincaltrials.gov identifier: NCT03825107 (31/01/2019).

Coordination between eye and hand movements is essential for children interacting with their environment. We previously reported slow reaching in children aged 7-12 years with impaired binocularity, specifically in the final approach (ie, deceleration phase). It is unclear when this deficit emerges, so we investigated hand kinematics during visually-guided reaching in younger children with impaired binocularity.

Coordination between eye and hand movements is essential for children interacting with their environment. We previously reported slow reaching in children with strabismus, specifically in the final approach. Here, we investigate saccades during visually-guided reaching to determine the contribution of eye movements to deficits observed in children with strabismus.

Purpose We recently found slow visually guided reaching in strabismic children, especially in the final approach. Here, we expand on those data by reporting saccade kinematics and temporal eye–hand coordination during visually guided reaching in children treated for strabismus compared with controls. Methods Thirty children diagnosed with esotropia, a form of strabismus, 7 to 12 years of age and 32 age-similar control children were enrolled. Eye movements and index finger movements were recorded. While viewing binocularly, children reached out and touched a small dot that appeared randomly in one of four locations along the horizontal meridian (±5° or ±10°). Saccade kinematic measures (latency, accuracy and precision, peak velocity, and frequency of corrective and reach-related saccades) and temporal eye–hand coordination measures (saccade-to-reach planning interval, saccade-to-reach peak velocity interval) were compared. Factors associated with impaired performance were also evaluated. Results During visually guided reaching, strabismic children had longer primary saccade latency (strabismic, 195 ± 29 ms vs. control; 175 ± 23 ms; P = 0.004), a 25% decrease in primary saccade precision (0.15 ± 0.06 vs. 0.12 ± 0.03; P = 0.007), a 45% decrease in the final saccade precision (0.16 ± 0.06 vs. 0.11 ± 0.03; P < 0.001), and more reach-related saccades (16 ± 13% of trials vs. 8 ± 6% of trials; P = 0.001) compared with a control group. No measurable stereoacuity was related to poor saccade kinematics. Conclusions Strabismus impacts saccade kinematics during visually guided reaching in children, with poor binocularity playing a role in performance. Coupled with previous data showing slow reaching in the final approach, the current saccade data suggest that children treated for strabismus have not yet adapted or formed an efficient compensatory strategy during visually guided reaching.

PURPOSE. Eye-hand coordination is essential for normal development and learning. Discordant binocular experience from childhood strabismus results in sensory and ocular motor impairments that can affect eye-hand coordination. We assessed reach kinematics during visually guided reaching in children treated for strabismus compared with controls. METHODS. Thirty-six children aged 7 to 12 years diagnosed with esotropia, a form of strabismus, and a group of 35 age-similar control children were enrolled. Reach movements during visually guided reaching were recorded using the LEAP Motion Controller. While viewing binocularly, children reached out and touched a small dot that appeared randomly in one of four locations (+/- 5 degrees or +/- 10 degrees). Kinematic measures were reach reaction time, total reach duration, peak velocity, acceleration duration, and deceleration duration. Touch accuracy and factors associated with impaired reach kinematics were evaluated. RESULTS. Strabismic children had longer total reach duration (545 +/- 60 ms vs. 504 +/- 43 ms; P = 0.002), had longer deceleration duration (343 +/- 54 ms vs. 312 +/- 45 ms; P = 0.010), and were less accurate (93% +/- 6% vs. 96% +/- 5%, P = 0.007) than controls. No differences were found for reach reaction time, peak velocity, or acceleration duration (all Ps >= 0.197). Binocular dysfunction was more related to slow reaching than amblyopic eye visual acuity. CONCLUSIONS. Strabismus affects visually guided reaching in children, with slower reaching in the final approach and reduced endpoint accuracy. Binocular dysfunction was predictive of slow reaching. Unlike strabismic adults who show longer acceleration duration, longer deceleration in the final approach in strabismic children indicates a difference in control that could be due to reduced ability to use visual feedback.

BACKGROUND Reading relies on ocular motor function, requiring sequential eye movements (forward and regressive saccades). Binocularly discordant input from a dense congenital or infantile cataract is associated with ocular motor dysfunction and may affect the development of reading ability. The purpose of this study was to assess silent, binocular reading in children treated for unilateral congenital or infantile cataract. METHODS Twenty school-age children (age range, 7-13 years) treated for unilateral congenital (n = 9) or infantile (n = 11) cataract and 49 age-similar control children silently read a grade-appropriate paragraph during binocular viewing. Reading rate (words/min) and the number of forward and regressive saccades (per 100 words) were recorded using the ReadAlyzer. RESULTS Reading rate in children treated for a unilateral cataract did not differ significantly from controls (174 +/- 59 words/min vs 195 +/- 54 words/min; P = 0.1). However, they did have significantly more forward saccades (101 +/- 33 saccades/100 words vs 87 +/- 21 saccades/100 words; P = 0.03) but not regressive saccades (21 +/- 14 saccades/100 words vs 16 +/- 8 saccades/100 words; P = 0.1) compared with controls. Reading rate was not related to cataract type (congenital vs infantile), visual acuity outcome (poor vs good), or sensory fusion (fail vs pass; all P >= 0.1). CONCLUSIONS Reading rate of children treated for a dense unilateral cataract did not differ from that of controls. Increased forward saccades during reading may be due to fixation instability associated with fusion maldevelopment nystagmus prevalent in children following cataract extraction.

BACKGROUND Most clinical trials of contrast-rebalanced binocular amblyopia treatment used a contrast increment protocol of 10% daily with successful play. Paired with a definition of success requiring only 15-30 min/day of gameplay, this increment protocol could allow children to reach 100% fellow eye contrast in 3-9 hours; however, this may not provide adequate therapeutic time with reduced fellow eye contrast. The purpose of this study was to compare the original protocol against three alternative contrast increment protocols designed to increase the number of treatment hours. METHODS In this prospective study, 63 amblyopic children (4-10 years; amblyopic eye visual acuity, 20/40-125) were randomly assigned one of four daily contrast increment protocols for 4 weeks, all starting with 20% fellow eye contrast: 10%, 5%, 0%, or 10% for first 4 weeks then reset to 20% and repeat 10% increment for the final 4 weeks. Children played contrast-rebalanced games for 1 hour/day, 5 days/week. Best-corrected visual acuity, stereoacuity, and suppression were assessed at baseline and every 2 weeks until the 8-week outcome visit. RESULTS At baseline, mean amblyopic eye best-corrected visual acuity was 0.47 +/- 0.14 logMAR (20/ 60), improving overall 0.14 +/- 0.08 logMAR (1.4 lines; P < 0.0001) at 8 weeks. All four protocols resulted in similar improvement in visual acuity (0.13-0.16 logMAR; all Ps\ 0.0002). Stereoacuity and suppression also improved (all Ps < 0.05). CONCLUSIONS None of the new protocols resulted in less improvement than the original 10% contrast increment protocol. Contrast-rebalanced binocular games yielded significant improvements in visual acuity, stereoacuity, and suppression with or without daily contrast increments.

PURPOSE. We examined inferior oblique muscles from subjects with over-elevation in adduction for characteristics that might shed light on the potential mechanisms for their abnormal eye position. METHODS. The inferior oblique muscles were obtained at the time of surgery in subjects diagnosed with either primary inferior oblique overaction or Apert syndrome. The muscles were frozen and processed for morphometric analysis of myofiber size, central nucleation, myosin heavy chain (MyHC) isoform expression, nerve density, and numbers of neuromuscular junctions per muscle section. RESULTS. The inferior oblique muscles from subjects with Apert Syndrome were smaller, and had a much more heterogeneous profile relative to myofiber cross-sectional area compared to controls. Increased central nucleation in the Apert syndrome muscles suggested on-going myofiber regeneration or reinnervation over time. Complex changes were seen in the MyHC isoform patterns that would predict slower and more sustained contractions than in the control muscles. Nerve fiber densities were significantly increased compared to controls for the muscles with primary inferior oblique overaction and Apert syndrome that had no prior surgery. The muscles from Apert syndrome subjects as well as those with primary inferior oblique overaction with no prior surgery had significantly elevated numbers of neuromuscular junctions relative to the whole muscle area. CONCLUSIONS. The muscles from both sets of subjects were significantly different from control muscles in a number of properties examined. These data support the view that despite similar manifestations of eye misalignment, the potential mechanism behind the strabismus in these subjects is significantly different.

BACKGROUND:Binocular amblyopia treatments promote visual acuity recovery and binocularity by rebalancing the signal strength of dichoptic images. Most require active participation by the amblyopic child to play a game or perform a repetitive visual task. The purpose of this study was to investigate a passive form of binocular treatment with contrast-rebalanced dichoptic movies. METHODS:A total of 27 amblyopic children, 4-10 years of age, wore polarized glasses to watch 6 contrast-rebalanced dichoptic movies on a passive 3D display during a 2-week period. Amblyopic eye contrast was 100%; fellow eye contrast was initially set to a lower level (20%-60%), which allowed the child to overcome suppression and use binocular vision. Fellow eye contrast was incremented by 10% for each subsequent movie. Best-corrected visual acuity, random dot stereoacuity, and interocular suppression were measured at baseline and at 2 weeks. RESULTS:Amblyopic eye best-corrected visual acuity improved from 0.57 ± 0.22 at baseline to 0.42 ± 0.23 logMAR (t26 = 8.09; P < 0.0001; 95% CI for improvement, 0.11-0.19 logMAR). Children aged 3-6 years had more improvement (0.21 ± 0.11 logMAR) than children aged 7-10 years (0.11 ± 0.06 logMAR; t25 = 3.05; P = 0.005). Children with severe amblyopia (≥0.7 logMAR) at baseline experienced greater improvement (0.24 ± 0.12 logMAR) than children with moderate amblyopia at baseline (0.12 ± 0.06 logMAR; t25 = 3.49; P = 0.002). CONCLUSIONS:In this cohort, passive viewing of contrast-rebalanced dichoptic movies effectively improved visual acuity in amblyopic subjects. The degree of improvement observed was similar to that previously reported for 2 weeks of binocular games treatment and with 3-4 months of occlusion therapy.

The surgical treatment of the adult with strabismus comprises a significant portion of the clinical and surgical volume of many pediatric ophthalmologists. This workshop is designed to educate attendees regarding surgical treatment of adults with strabismus.

PURPOSE To evaluate fine motor ability in children treated for unilateral congenital or infantile cataract. METHODS Twenty-three children 3-13 years of age who were treated for unilateral congenital or infantile cataract and 38 age-similar control children were enrolled. Children completed five fine motor skills tasks (unimanual dexterity, bimanual dexterity, drawing trail, aiming, catching) from the Movement Assessment Battery for Children-2. Raw scores were converted into standardized scores, with higher scores indicating better performance. RESULTS Compared with controls, children treated for unilateral cataract scored lower on drawing trail (P = 0.009), aiming (P = 0.009), and catching (P < 0.001) but not on unimanual (P = 0.77) or bimanual dexterity (P = 0.31). Poorer affected eye visual acuity was moderately related to poorer performance for unimanual dexterity (r = -0.47; P = 0.025), bimanual dexterity (r = -0.50; P = 0.014), and catching (r = -0.41; P = 0.051). Those with a poor visual outcome (>0.6 logMAR) had worse performance than those with a good visual outcome (<= 0.6 logMAR) for all tasks (all P values, 0.008-0.09) except aiming. Cataract type (congenital, 9; infantile, 14) and sensory fusion by Worth 4-Dot testing at 33 cm (pass, 10; fail, 13) had no effect on fine motor performance (all P values, 0.12-0.98). CONCLUSIONS In our study cohort, fine motor deficits were found in children treated for congenital or infantile unilateral cataract.

BACKGROUND Previous studies show slow reading in strabismic amblyopia. We recently identified amblyopia, not strabismus, as the key factor in slow reading in children. No studies have focused on reading in amblyopic children without strabismus. We examined reading in anisometropic children and evaluated whether slow reading was associated with ocular motor dysfunction in children with amblyopia. METHODS Anisometropic children (7-12 years) with or without amblyopia were compared to age similar normal controls. Children silently read a grade-appropriate paragraph during binocular viewing. Reading rate (words/min), number of forward and regressive saccades (per 100 words) and fixation duration were recorded with the ReadAlyzer. Binocular fixation instability was also evaluated (EyeLink 1000). RESULTS Amblyopic anisometropic children read more slowly (n = 25; mean with standard deviation, 149 +/- 42 words/min) than nonamblyopic anisometropic children (n = 15; 196 +/- 80 words/min; P = 0.024) and controls (n = 25; 191 +/- 65 words/min; P = 0.020). Nonamblyopic anisometropic children read at a comparable rate to controls (P = 0.81). Slow reading in amblyopic anisometropic children was correlated with increased forward saccades (r = -0.84, P < 0.001), increased regressive saccades (r = -0.85, P < 0.001), and fellow eye instability during binocular viewing (r = -0.52, P = 0.019). CONCLUSIONS Slow reading in school-age children with anisometropic amblyopia is related to increased frequency of saccades and fixation instability of the fellow eye. Further research should consider the effects of slower reading on academic performance.