Changes in binocular function in anisometropic nonstrabismic children with optical correction and occlusion therapy

Evaluation of the clinical effect of 4D digital strabismus and amblyopia visual function correction system combined with traditional comprehensive treatment methods on anisometropic amblyopia

PURPOSE

The objective of this study was to evaluate the clinical efficacy of a 4D digital strabismus and amblyopia visual function correction system (4D-DSAAVFCS) in combination with conventional modalities compared with conventional modalities alone in children with anisometropic amblyopia.

METHODS

This nonrandomized controlled study collected data on best-corrected visual acuity (BCVA), simultaneous vision, fusion vision, near stereoscopic vision, the amplitude of P100 wave (graphic evoked visual potentials), and the latency of P100 wave from both eyes at the beginning of the treatment and one year later. The Mann‒Whitney U test was used to compare BCVA contrasts in different subgroups, and the independent samples t test was used to compare the amplitude and latency of P100 wave contrasts in different subgroups. The basic cure rate, simultaneous vision recovery rate, fusion vision recovery rate, and near stereoscopic vision recovery rate contrasts in different subgroups were compared via the chi-square test.

RESULTS

This study included 393 children (217 boys and 176 girls) aged 3 to 12 years with anisometropic amblyopia who were treated at the Aier Eye Hospital of Wuhan University from January 2020 to December 2022. The children were divided into two groups, the 4D group (263 cases) and the traditional group (130 cases), on the basis of the treatment modality. The children in the traditional group received treatment through the conventional method of occlusion and regular training. Meanwhile, the children in the 4D group received treatment through the traditional method and the 4D-DSAAVFCS. The 4D group was divided into two age groups: 3 ~ 6 years (161 cases) and 6 ~ 12 years (102 cases). The basic cure rate of the 4D group was significantly better than that of the traditional group (χ2 = 4.318, P < 0.05). There were no statistically significant differences in the BCVA, the latency of P100 wave, or the amplitude of P100 wave between the 4D group and the traditional group before treatment (U=-0.117, t=-0.05, all P > 0.05 ). After one year of treatment, a statistically significant difference was observed between the 4D group and the conventional group in terms of BCVA, the latency of P100 wave, and the amplitude of P100 wave (U=-1.243, t=-0.853, t=-1.546, all P < 0.05). These results suggest that the therapeutic effect was greater in the 4D group than in the conventional group. The recovery rates of simultaneous vision, convergent fusion, divergent fusion, and near stereoscopic vision were significantly greater in the 4D group than in the conventional group (χ2 = 4.344, 4.726, 5.123, and 2.036, respectively; all P < 0.05). Additionally, the basic cure rate of children aged 3 ~ 6 years in the 4D group was significantly greater than that of children aged 6 ~ 12 years (χ2 = 2.365, P < 0.05). In this study, BCVA was significantly lower in the 3 ~ 6-year-old group than in the 6 ~ 12-year-old group (U = -1.267, P < 0.05). Similarly, the amplitude of P100 wave was also significantly greater in the 3 ~ 6-year-old group than in the 6 ~ 12-year-old group (t = -1877, P < 0.05). The latency of P100 wave was lower in the 3 ~ 6-year-old group than in the 6 ~ 12-year-old group (t=-0.998, P < 0.05). Additionally, the recovery rate of near stereoscopic vision was significantly greater in the 3 ~ 6-year-old group than in the 6 ~ 12-year-old group (χ2 = 4.534, P < 0.05).

CONCLUSION

The combination of the traditional method with the 4D-DSAAVFCS was more effective than the traditional method alone in treating amblyopic children. This approach was particularly helpful in improving the visual acuity of the children and restoring their optic nerve conduction function, simultaneous vision, fusion vision, and near stereoscopic vision. The combination of the traditional method and the 4D-DSAAVFCS is more effective for younger children.

The Association Between Improvement of Stereoacuity and Suppression in the Treatment of Anisometropic Amblyopia

Purpose

To investigate the association between stereoacuity and suppression during occlusion therapy for patients with anisometropic amblyopia.

Design

Retrospective study.

Patients and Methods

This study included 19 patients with hyperopic anisometropic amblyopia who underwent occlusion therapy. The mean age of the patients was 5.5 ± 1.4 years. The participants were evaluated for improvement in stereoacuity and suppression before beginning occlusion therapy, when the highest amblyopic visual acuity (VA) was achieved, during tapering, at the end of occlusion therapy, and at the final visit. Stereoacuity was evaluated using the TNO test or JACO stereo test. The presence of suppression was evaluated using circle No. 1 of the Stereo Fly Test or JACO results as the optotype.

Results

Of the 19 patients, 13 (68.4%) had suppression before occlusion, eight (42.1%) when the highest VA was achieved, five (26.3%) during tapering, and none at the final visit. Of the 13 patients with suppression before occlusion, 10 (76.9%) showed further improvement in stereoacuity when suppression disappeared, and nine had foveal stereopsis of 60 arcseconds. A significant association was confirmed between foveal stereopsis and suppression when the highest VA was achieved and during the tapering period (P<0.05, Fisher's exact test).

Conclusion

Suppression was observed even when the VA in amblyopic eyes reached the highest score. By gradually decreasing the duration of occlusion, suppression was eliminated, leading to the acquisition of foveal stereopsis.

Long-term visual and treatment outcomes of whole-population pre-school visual screening (PSVS) in children: a longitudinal, retrospective, population-based cohort study

BACKGROUND

This study reports the long-term visual and treatment outcomes in a whole-population, orthoptic-delivered pre-school visual screening (PSVS) programme in Scotland and further examines their associations with socioeconomic backgrounds and home circumstances.

METHODS

Retrospective case review was conducted on 430 children who failed PSVS. Outcome measures included best corrected visual acuity (BCVA), severity of amblyopia (mild, moderate and severe), binocular vision (BV) (normal, poor and none), ophthalmic diagnosis and treatment modalities. Parameters at discharge were compared to those at baseline and were measured against the Scottish index of multiple deprivation (SIMD) and Health plan indicator (HPI), which are indices of deprivation and status of home circumstances.

RESULTS

The proportion of children with amblyopia reduced from 92.3% (373/404) at baseline to 29.1% (106/364) at discharge (p < 0.001). Eighty percent (291/364) had good BV at discharge compared to 29.2% (118/404) at baseline (p < 0.001). Children from more socioeconomically deprived areas (OR 2.19, 95% CI 1.01-4.30, p = 0.003) or adverse family backgrounds (OR 3.94, 95% CI 1.99-7.74, p = 0.002) were more likely to attend poorly and/or become lost to follow-up. Children from worse home circumstances were five times more likely to have residual amblyopia (OR 5.37, 95% CI 3.29-10.07, p < 0.001) and three times more likely to have poor/no BV (OR 3.41, 95% CI 2.49-4.66, p < 0.001) than those from better home circumstances.

CONCLUSIONS

Orthoptic-delivered PSVS is successful at screening and managing amblyopia. Children from homes requiring social care input are less likely to attend and are more likely to have poorer visual outcomes.

The Role of Binocularity in Anisometropic Amblyopia

Anisometropic amblyopia is unilateral by definition and current treatment recommendations reflect that characteristic. However, recent research suggests a binocular component that deserves consideration. The aim of this review is to consider the levels of anisometropia deemed amblyogenic, and the cortical changes that occur in the presence of anisometropic amblyopia. Particular attention is given to cortical changes that impact the binocularity of these individuals. Knowledge of binocular deficits in anisometropic amblyopia has implications for current, accepted treatment regimens which are monocular in nature. Therefore, the integrity of binocular function in anisometropic amblyopia and its impact on the visual outcome will be evaluated. Given the rise in binocular treatments under clinical trial for amblyopia, this review also aims to evaluate the evidence of potentially enhanced benefits to anisometropic amblyopes from proposed new binocular therapies.

The Effects of Anisometropic Amblyopia on the FNS and TNO Stereotest Thresholds in Four- to Eight-Year-Olds

Purpose

To investigate the relationship between stereoacuity and factors associated with anisometropic amblyopia in children aged 4-8 years.

Methods

44 participants had their stereoacuity thresholds measured using the Frisby Near Stereotest (FNS) and the TNO Randot Stereotest (TNO). Participants were divided into anisometropic amblyopes and controls (normal uniocular visual acuity (VA) with or without glasses). FNS and TNO stereoacuity thresholds were compared based on different factors, which included interocular acuity difference (IAD), VA levels, and the degree of anisometropia.

Results

All 44 participants achieved better stereoacuity with the FNS compared to the TNO (p = 0.045). The control group performed significantly better on the FNS (p = 0.012) and the TNO (p = 0.009) when compared with anisometropic amblyopes. The only statistically significant correlation was found between stereoacuity - as measured with FNS - and IAD (p = 0.009). However, the TNO showed a correlation in the presence of poor VA, larger IADs and a high degree of anisometropia.

Conclusions

Stereoacuity thresholds are significantly affected by poor VA, large IAD and high degrees of spherical anisometropia when trying to distinguish the resolution of a target with the TNO yet the same factors do not appear to affect ability to distinguish the disparity of a target with the FNS. Controls also performed worse on the TNO.

Interocular Difference of Peripheral Refraction in Anisomyopic Eyes of Schoolchildren

Purpose

Refraction in the peripheral visual field is believed to play an important role in the development of myopia. The purpose of this study was to investigate the differences in peripheral refraction among anisomyopia, isomyopia, and isoemmetropia for schoolchildren.

Methods

Thirty-eight anisomyopic children were recruited and divided into two groups: (1) both eyes were myopic (anisomyopic group, AM group) and (2) one eye was myopic and the contralateral eye was emmetropic (emmetropic anisomyopic group, EAM group). As controls, 45 isomyopic and isoemmetropic children were also recruited with age and central spherical equivalent (SE) matched to those of the AM and EAM groups. The controls were divided into three groups: (1) intermediate myopia group (SE matched to the more myopic eye of AM group), (2) low myopia group (SE matched to the less myopic eye of AM group and the more myopic eye of EAM group), and (3) emmetropia group (SE matched to the less myopic eye of EAM group). Peripheral refraction at 7 points across the central ±30° on the horizontal visual field with a 10° interval was measured with an autorefractor. Axial length (AL), corneal curvature (CC), and anterior chamber depth (ACD) were also determined by using the Zeiss IOL-Master.

Results

The relative peripheral spherical equivalent [RPR(M)] and relative peripheral spherical value [RPR(S)] of the more myopic eye was shifted more hyperopically than the contralateral eye in both the AM and the EAM groups (both p<0.0001). The RPR(M, S) of the less myopic eyes in the AM and EAM groups showed a relatively flat trend across the visual field and were not significantly different from the emmetropia group. The RPR(M, S) of less myopic eyes in the AM group were shifted less hyperopically than in the isomyopic low myopia group and the more myopic eye of the EAM group [RPR(M), p = 0.007; RPR(S), p = 0.001], although the central SEs of the three groups were not significantly different from each other. However, RPR(M, S) of the more myopic eyes were not different from the corresponding isomyopic groups. There was also no significant difference in the relative peripheral astigmatism [RPR(J0, J45)] between the more and the less myopic eyes in either the AM or the EAM group.

Conclusion

Refraction of anisomyopia differs between the two eyes not only at the central visual field but also at the off-axis periphery. The relative peripheral refraction of the more myopic eye of anisomyopia was shifted hyperopically, as occurs in isomyopia with similar central subjective SE values. Less myopic eyes were much less hyperopically shifted in relative peripheral refraction than the corresponding isomyopic eyes, but are comparable to emmetropic eyes. This emmetropia-like relative peripheral refraction in less myopic eyes might be a factor responsible for slowing down the progression of myopia.

Treatment outcomes of myopic anisometropia with 1% atropine: a pilot study

PURPOSE

To investigate the safety and efficacy of the treatment of myopic anisometropia with 1% atropine.

METHODS

Twenty-two children with myopic anisometropia were prescribed 1% solution of atropine sulfate to the more myopic eye, one drop before sleep every 3 days. Children were visited every 3 to 4 months until the degree of anisometropia was no more than 0.5 diopters (D) ("Success") or unchanged after 9 months of treatment ("No effect"). The treatment effect was assessed by comparing the interocular imbalance in refraction and axial length before and after the treatment. A detailed questionnaire about subjective symptoms in each visit and an electroretinogram in the end were administered to evaluate the side effects of this treatment.

RESULTS

The subjects were followed for 7 to 16 months. Six subjects withdrew participation on their own accord, and three were excluded because of inconstant usage of drug. Of the 13 remaining subjects, the refraction of the treated eyes decreased by 0.63 ± 0.59 D (p = 0.007), whereas that of the untreated eyes increased by -0.72 ± 0.65 D (p < 0.001). A corresponding trend was also found in the change of the axial length. Accordingly, the level of anisometropia was reduced from 1.82 ± 0.73 D to 0.47 ± 0.65 D (p < 0.001) and 10 (76.9%) of the 13 subjects were designated a "Success." One percent atropine was well tolerated by the children, and no electroretinogram abnormality was detected.

CONCLUSIONS

The results from this pilot study indicate that monocular usage of a solution of 1% atropine sulfate is an effective treatment to reduce anisometropia, although with some tolerable side effects. Nevertheless, an attenuated benefit was observed after cessation of atropine treatment. Thus, participants should be informed of a possible rebound effect before the administration of atropine for myopic anisometropia.