The effects of hyperopic and astigmatic ametropia on stereoacuity by Titmus stereo test

A comparative study of stereopsis in term and preterm children with and without retinopathy of prematurity

PURPOSE

To evaluate stereopsis in term-born, preterm, and preterm children with and without retinopathy of prematurity (ROP) and its treatment.

METHODS

The cross-sectional study included 322 children between 3 and 11 years of age born term or preterm, with or without ROP, and with or without treatment for ROP. The ROP treatments were laser therapy, intravitreal injection (IVI) of anti-vascular endothelial growth factor, or their combination. Stereoacuity was measured using the Titmus Stereo Test, and the results among various age groups were analyzed.

RESULTS

Stereopsis was found to improve with increasing age at testing (P < 0.001) across the entire study population. The term group exhibited significantly better stereoacuity than the preterm group (P < 0.001). At 3-5 years and 6-8 years, the preterm children without ROP exhibited significantly better stereoacuity than did those with ROP (P < 0.001 and P = 0.02, respectively); however, at 9-11 years, both groups exhibited similar stereoacuity (P = 0.34). The stereoacuity in the children with untreated ROP was similar to that of the children with treated ROP in all age groups (P > 0.05). No significant differences in stereopsis were identified between children with ROP treated with laser versus with IVI (P > 0.05). From multivariate analysis, younger age at testing (P = 0.001) and younger gestational age (P < 0.001) were associated with poorer stereopsis.

CONCLUSIONS

Stereopsis development gradually improved with age in all groups. The children born preterm exhibited poorer stereoacuity than those born term. Children with ROP treated with laser photocoagulation versus IVI may exhibit similar levels of stereoacuity. Younger age at testing and gestational age were independent risk factors for poorer stereoacuity.

Long-term surgical outcomes of basic-type exotropia in patients with hyperopia

BACKGROUND

To investigate the surgical outcomes of basic-type exotropia in patients with hyperopia.

METHODS

The medical records of patients who underwent surgery for basic-type exotropia and had been followed up for ≥ 2 years were retrospectively recruited. Patients with myopia and spherical equivalent (SE) < -1.0 diopters (D) were excluded. The patients were classified according to the SE: group H had a SE ≥  + 1.0 D, and group E had -1.0 ≤ SE <  + 1.0 D. The surgical success rate and sensory outcome were compared. Surgical success was defined as exodeviation ≤ 10 prism diopters (PD) and esodeviation ≤ 5 PD at 6 m fixation. Stereoacuity was measured using the Titmus Preschool Stereoacuity Test.

RESULTS

Seventy-five patients (24 males and 51 females, mean age 5.1 ± 2.6 years, range 2.7-14.8) were included. The SE ranged from -0.9 to 4.4 and 21 patients were classified into group H and 54 into group E. The success rates were higher in group H than in group E during the entire follow-up period, but the differences were significant only at the final examination. At the final follow-up, 11 of the 21 (52.4%) patients in group H and 15 of the 54 (27.7%) in group E maintained successful alignment, whereas 10 (47.6%) and 38 (70.4%) patients exhibited recurrence. Overcorrection was exhibited in one (1.9%) patient in group E. Sensory results were comparable between the groups. The follow-up period did not differ between the two groups. The survival analysis showed no difference in the surgical results between the two groups.

CONCLUSIONS

Surgery for basic-type intermittent exotropia resulted in superior outcomes in patients with hyperopia compared to those with emmetropia.

A longitudinal study of local stereoacuity and associated factors in schoolchildren: The Shahroud Schoolchildren Eye Cohort Study

CLINICAL RELEVANCE

Impaired stereoacuity is seen in some children without amblyopia, strabismus, and clinically significant refractive errors. Therefore, there are probably other factors affecting stereoacuity.

BACKGROUND

The aim of this work was to investigate the longitudinal changes of local stereoacuity and associated factors in schoolchildren.

METHODS

The present report is a part of the Shahroud Schoolchildren Eye Cohort Study. The target population was children aged 6 to 12 years in Shahroud, Iran. The second phase of the study was conducted in 2018 by re-inviting all participants in the first phase (2015). After an initial interview, study participants underwent optometric examination and ocular biometry. Stereoacuity was evaluated using Stereo Fly Test. Exclusion criteria were functional amblyopia, strabismus, significant refractive errors, probable ocular pathology/organic amblyopia in either of the two study phases, a history of intraocular surgery or ocular trauma, and incomplete data.

RESULTS

The data of 4666 children were analysed for this report, of which 53.7% were male. The mean age of the studied participants in the second phase was 12.37 ± 1.71 years. The mean stereoacuity was 42.31 (95% CI: 42.05 - 42.57) seconds of arc in the first phase, which reduced to 51.72 (95% CI: 50.79-52.65) seconds of arc in the second phase (P < 0.001). The prevalence of poor stereoacuity was 0.17% (95% CI: 0.06-0.29) in the first phase, which increased to 3.94% (95% CI: 3.34-4.54) in the second phase (P < 0.001). According to the multiple linear regression, older age in the first study phase (β = 0.011, P < 0.001), urban residence (β = -0.019, P = 0.006), increased spherical anisometropia (0.038, P = 0.013), and increased axial length (β = 0.062, P = 0.003) were significantly associated with reduction of stereoacuity (in log scale) after three years.

CONCLUSION

In addition to the known risk factors of amblyopia, strabismus, and significant refractive errors, other factors are also associated with stereoacuity changes in children.

Stereopsis after corneal refractive surgeries: a systematic review and meta-analysis

PURPOSE

To systematically review the published manuscripts on stereopsis after corneal refractive surgery.

METHODS

The Web of Science, PubMed, Scopus, ProQuest, Clinical Key, Embase, and Cochrane Library were searched for relevant articles published until August 2020. The fixed- or random-effects models were used to estimate the Weighted mean difference (WMD) or Relative risk (RR) and 95% Confidence interval (CI) for postoperative stereopsis changes and incidence when applicable. Meta-regression was conducted for adjusting the effects of potential confounders.

RESULTS

Seven studies (1266 eyes) in adults and ten studies in pediatrics (259 eyes) were included. In adults, stereopsis improved significantly compared to the preoperative state (WMD = - 27.4, 95% CI = - 40.0, - 14.7; I² = 97.8%; P < 0.001). In pediatrics, proportion of patients with stereoacuity postoperatively was 2.18 times compared to preoperative evaluation. (RR = 2.18, 95% CI = 1.2, 3.9; I² = 68.6%, P < 0.001).

CONCLUSIONS

Stereopsis improves after corneal refractive surgery in adults and pediatrics.

Study on stereoacuity and associated factors in school children aged 7 to 14 years

Purpose:

The study aimed to estimate the prevalence of subnormal stereoacuity in school children and to assess the factors associated with it.

Methods:

In this prospective cross-sectional study, a total of 2,376 school children without amblyopia and manifest squint were screened by the titmus fly test, Snellen chart, tests for heterophoria, anterior segment examination, and fundoscopy. Children with a manifest squint, amblyopia (best-corrected visual acuity [BCVA] <6/18), and history of ocular trauma or surgery, and one-eyed children were excluded. Cycloplegic refraction was done in children with uncorrected or undercorrected refractive errors, and stereoacuity was assessed again with spectacle correction.

Results:

The prevalence of normal stereoacuity by titmus fly test was 93.18% with correction of refractive errors. Girls had slightly better stereopsis compared with boys. The subnormal stereoacuity was significantly associated with refractive error (P < 0.00001, significant at P < 0.05), unilateral refractive error (P < 0.00001, significant at P < 0.05), bilateral refractive error (P < 0.00001, significant at P < 0.05), anisometropia (P < 0.00001, significant at P < 0.05), ametropia (P < 0.00001, significant at P < 0.05), lower BCVA (P < 0.00001, significant at P < 0.05), hyperopia (P < 0.05, significant at P < 0.05), and heterophoria (P = 0.014, significant at P < 0.05). The subnormal stereoacuity was positively correlated with the magnitude of refractive error of the eyes.

Conclusion:

This study underlines the significant impact of identification and correction of refractive errors and squints in school children. The measurement of stereoacuity will be of immense importance and must be included in the screening programs for children.

Stereoacuity Among Patients with Refractive Error at University of Gondar, Northwest Ethiopia

PURPOSE

This study aimed to assess the level of stereopsis, proportion of poor stereopsis, and factors influencing stereopsis in adults with refractive error.

METHODS

This was a cross-sectional, descriptive study conducted on 153 adults with refractive error at Gondar University Hospital Tertiary Eye Care Center from April 08 to June 07, 2019. Structured questionnaires and ophthalmic instruments (Retinoscope, Worth Four Dot test and TNO Stereo plates) were used to collect the data. Data were entered and analyzed with Statistical Package for Social Sciences (SPSS) version 20. The result was summarized using summary statistics such as mean. Chi-squared test of association was applied between stereopsis and independent variables.

RESULTS

The level of stereopsis after correction of refractive error ranged from 1.89 to 2.65 log arc second. Before correction of refractive error, poor stereopsis was observed in 46.4% of the participants, while after correction, it dropped to 39.8% (CI: 95%: 31.1%-47.8%). Stereopsis after correction had a significant association with age, best visual acuity, type of refractive error, and fusional status at distance with a p value < 0.05.

CONCLUSION

Given refractive error corrected, the mean stereopsis in patients with refractive error was 2.42 log arc second. Proportion of poor stereopsis was noted in 39.8% of the participants corrected for refractive error. Age, best corrected visual acuity, type of refractive error, and fusional status had a significant association with stereopsis. Further studies on stereoacuity on a large scale are recommended.

Stereoacuity and refractive, accommodative and vergence anomalies of South African school children, aged 13–18 years

Aim: The aim of this study was to explore possible associations between stereoacuity and refractive, accommodative and vergence anomalies.Methods: The study design was cross-sectional and comprised data from 1056 high school children aged between 13 and 18 years; mean age and standard deviation were 15.89 ± 1.58 years. Using a multi-stage random cluster sampling, participants were selected from 13 high schools out of a sample frame of 60 schools in the municipality concerned. In the final sample, 403 (38%) were males and 653 (62%) females. Refractive errors, heterophoria, near point of convergence, fusional vergences and accommodative functions (amplitude, facility, response and relative) were evaluated. Stereoacuity was evaluated using the Randot stereotest and recorded in seconds of arc where reduced stereoacuity was defined as worse than 40 s arc.Results: Overall, the mean stereoacuities (in seconds of arc) of the children with anomalies were the following: those with refractive errors (52.6 ± 36.9), with accommodative anomalies (53.1 ± 34.1) and with vergence anomalies (48.29 ± 31.1). The mean stereoacuity of those with vergence anomalies was significantly better than that of those with either refractive errors or accommodative anomalies (p = 0.02). In the refractive error category, only anisometropia had significantly reduced mean stereoacuity compared to emmetropia (Mann–Whitney U: p = 0.01). The mean stereoacuity of cases of accommodative anomalies was significantly reduced compared to those without such anomalies (Mann–Whitney U: p = 0.01). Similarly, the mean stereoacuity of cases with vergence anomalies was significantly reduced compared to those without vergence anomalies (p = 0.02).Conclusion: Refractive errors, accommodative or vergence anomalies are more likely to have reduced mean stereoacuity than cases without such anomalies. Refractive errors or accommodative anomalies had significantly more reduced stereoacuity than vergence anomalies. These findings suggest that the Randot stereotest could be used to identify those with such anomalies, and this study extends knowledge regarding the possible use of stereoacuity as a useful tool to screen for binocular anomalies.

Stereoscopic visual acuity in types of ametropic amblyopia in children

PURPOSE

To evaluate the presence of stereopsis in children with ametropic amblyopia, including hyperopia, myopia, and astigmatism.

METHODS

A total of 205 children with the average age of 5.2 years were selected, including 65 cases of astigmatic amblyopia, 30 of myopic amblyopia, and 110 of hyperopic amblyopia. The near stereoacuity test (zero disparity stereoacuity, crossed disparity, and uncrossed disparity) and distance stereoacuity test by synoptophore with Yan's random-dot test in The Examination Chart of Stereoscopic Acuity were performed. Visual acuity was examined with the standard Snellen chart. Distance fusion was determined with the synoptophore. Correlations between amblyopia and stereopsis were performed with logistic procedure.

RESULTS

Differences between zero disparity stereoacuity of hyperopia, myopia, and astigmatism were statistically significant in children with mild and moderate amblyopia determined by the near stereoacuity test (P < .05). Individuals with hyperopia have better central stereopsis and macular stereopsis, whereas children with astigmatism have significantly decreased stereoacuity. No difference was identified between the three types in children with severe amblyopia (P > .05). Results of different degrees of amblyopia at distance and near were approximate. In amblyopic eyes, difference between hyperopia, myopia, and astigmatism, determined with synoptophore, was not significant (P > .05). The types and degrees of amblyopia were closely related with stereopsis (P < .001).

CONCLUSIONS

In mild and moderate amblyopic eyes, children with astigmatism had the worst stereoacuity. This group should pay more attention to visual stimulation training and stereopsis training.