Vision screening for children: current trends, technology, and legislative issues

Current Challenges Supporting School-Aged Children with Vision Problems: A Rapid Review

Many children have undetected vision problems or insufficient visual information processing that may be a factor in lower academic outcomes. The aim of this paper is to contribute to a better understanding of the importance of vision screening for school-aged children, and to investigate the possibilities of how eye-tracking (ET) technologies can support this. While there are indications that these technologies can support vision screening, a broad understanding of how to apply them and by whom, and if it is possible to utilize them at schools, is lacking. We review interdisciplinary research on performing vision investigations, and discuss current challenges for technology support. The focus is on exploring the possibilities of ET technologies to better support screening and handling of vision disorders, especially by non-vision experts. The data orginate from a literature survey of peer-reviewed journals and conference articles complemented by secondary sources, following a rapid review methodology. We highlight current trends in supportive technologies for vision screening, and identify the involved stakeholders and the research studies that discuss how to develop more supportive ET technologies for vision screening and training by non-experts.

The effect of developmentally-at-risk status on the reliability of the iScreen® photorefractive device in young children

INTRODUCTION AND PURPOSE

We evaluated the impact of developmentally-at-risk status on the results of photorefractive screening with iScreen®.

PATIENTS AND METHODS

We sequentially recruited 169 children (aged 2-5 years) to participate in a blinded, prospective study of a photoscreening device. The principle investigator examined the children after photoscreening. Using established standards for amblyogenic factors, the principle investigator and photoscreen interpreters separately made a determination of "normal" or "needs referral" for each child. Sensitivity, specificity, positive predictive value, and negative predictive value for the photoscreening device were determined.

RESULTS

Overall, sensitivity was 85% with a positive predictive value of 98%, and specificity was 87% with a negative predictive value of 47%. Developmentally-at-risk status in 34 children (three refused imaging) did not reduce sensitivity (89%) or specificity (100%) when compared with 130 children (two refused imaging) who did not have developmentally-at-risk factors (sensitivity = 84% and specificity = 80%).

CONCLUSION

The efficacy of photorefractive screening in young children with developmentally-at-risk status is comparable to results found in normal children.

Validity of vision screening tests by teachers among school children in Mashhad, Iran

PURPOSE

To determine the sensitivity and specificity of vision screening in Iranian schools where teachers have provided screening services for over 10 years.

METHODS

In a cross-sectional study, using random cluster sampling, 1163 school children were selected from 14 clusters. Data of vision tests performed by teachers were derived from 847 student records and compared with data obtained by optometrists. Measurement of the uncorrected visual acuity was done using the E chart by both the teachers and the optometrists. Examinations performed by optometrists were regarded as gold standard in this study and the sensitivity and specificity of the examinations performed by teachers were evaluated against them. Uncorrected visual acuity worse than 20/25 in the better eye was considered as the cut-off point for students' visual impairment.

RESULTS

The sensitivity and specificity of the screening tests performed by the teachers were 37.5% and 92.0%, respectively. The positive and negative predictive values were 25.0% and 95.4%, respectively. There was no significant difference in the validity of the vision test between males and females (P = 0.093 for sensitivity and P = 0.052 for specificity).

CONCLUSION

Our findings showed that teachers missed a significant number of children with vision impairment and the examinations performed by teachers lacked the required sensitivity for case detection. The number of false negative results should be minimized through continued investment in accurate screening processes.

Computer-based real-time analysis in mobile ocular screening

Mobile ocular telemedicine is potentially an effective method to provide service in medically underserved areas and to screen large populations for abnormalities. Currently, digital images are acquired, stored, and transferred to readers for evaluation, after which the results are provided to the subjects. The transfer of large image files and the timeliness of the subsequent reading of images are significant factors for practical implementation of effective telemedicine screening. This work examines the feasibility of in situ real-time computer analysis of digital images to determine and classify the image results as normal and abnormal. This retrospective study used a photoscreening database of 360 patients ranging in ages from 6 months to 18 years. Computer analysis automatically classified the binocular photorefraction (PR) images, and these PR results were compared to those of the subjective clinical eye examinations provided. With an average processing time of approximately 15 seconds per examinee, the analysis found that the PR results can be categorized as: a positive group that requires referral (186 cases) with a predictive value of 98.9% (2 false-positives); a negative group (144 cases) with a predictive value of 89.6% (15 false-negatives); and an uncertain group (30 cases or 8.3%) that required resolution by readers. The real-time analysis code reduces by approximately 92% the manpower for image grading and electronic transmission at this stage of ocular evaluation. These results indicate the feasibility of this approach.