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• Author's reply: Vision screening in children by Plusoptix Vision Screener
  Anthony J Vivian
  Published on: 22 March 2016
• Vision screening in children by Plusoptix Vision ScreenerTM compared with gold standard orthoptic as
  Robert W Arnold
  Published on: 22 March 2016

• Published on: 22 March 2016

  Author's reply: Vision screening in children by Plusoptix Vision Screener

  • Anthony J Vivian, Paediatric Ophthalmologist
  • Other Contributors:
    • Annegret Dahlmann

  Dear Editor,

  We thank Dr Arnolds and Ms Matta for their letter regarding our article Vision screening in children by Plusoptix Vision ScreenerTM compared with gold standard orthoptic assessment Dahlmann-Noor et al. (19 November 2008). We agree that a child vision screening tool that could be used effectively with minimal input from healthcare personnel would be desirable. This, together with the National Screenin...

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  Dear Editor,

  We thank Dr Arnolds and Ms Matta for their letter regarding our article Vision screening in children by Plusoptix Vision ScreenerTM compared with gold standard orthoptic assessment Dahlmann-Noor et al. (19 November 2008). We agree that a child vision screening tool that could be used effectively with minimal input from healthcare personnel would be desirable. This, together with the National Screening Committee ( UK) directive that all children should undergo vision screening between the age of 4-5 years stimulated our interest in the Plusoptix Vision Screener.

  Contrary to their interpretation of Table 3 in our article, the Plusoptix is not able to detect most refractive errors. This study was a vision screening investigation, with a study population of mostly emmetropic children. When the prevalence of refractive errors is low, the Plusoptix may appear to perform well. However, it fails to identify children with significant hypermetropia even when it causes a reduction in visual acuity, probably because of device-induced fixation myopia.

  Whilst the present study investigated the performance of the Plusoptix as a vision screening tool, its refractive performance is subject of a different study we conducted (Plusoptix Vision ScreenerTM: The accuracy and repeatability of refractive measurements using a new autorefractor. Dahlmann-Noor AH, Comyn O, Kostakis V, Misra A, Gupta N, Heath J, Brown J, Iron A, McGill S, Vrotsou K, Vivian AJ. Br J Ophthalmol. 2008 Nov 10. [Epub ahead of print]). This article is currently available online and will appear in print soon. In this second study, all subjects underwent cycloplegic refraction allowing for a meaningful assessment of the refractive performance of the Plusoptix. Many of Dr Arnold and Ms Matta’s points occurred to us as well, and are addressed by this second study. The idea that changing the cut-off criteria could improve sensitivity is sensible but when we did re-analyse data with different cutoff values (as explained in the discussion) this resulted in a lowering of specificity with very modest improvement of sensitivity as would be expected if the under-estimation of hypermetropia is caused by accommodation by the child on the machine at 1 metre.

  Whereas the prevalence of amblyopia in most populations is between 2- 4%, the combined prevalence of amblyopia. strabismus and significant refractive errors reducing visual acuity is considerably greater. We report an orthoptic referral rate of 12.5% in our study with only two false positives in this group. The limitation of an orthoptist-only screening program is that refraction is not part of the screening, hence the desire to find a sensitive and specific refraction tool.

  In our view, the Plusopix Vision Screener has many plus points, but until the problem with fixation-induced myopia is overcome, its lack of sensitivity limits its use as a stand-alone child vision screening device.

  Again, we wish to thank Dr Arnolds and Ms Matta for their interest and hope that the answers we have provided clarify the concerns they have raised.

  AJ Vivian and A. H. Dahlmann-Noor

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  Conflict of Interest:
  None declared.

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• Published on: 22 March 2016

  Vision screening in children by Plusoptix Vision ScreenerTM compared with gold standard orthoptic as

  • Robert W Arnold, Pediatric Ophthalmologist
  • Other Contributors:
    • Noelle Matta, certified orthoptist

  American pediatricians, armed with a new reimbursement code for photoscreening young children (99174), are very interested in the validity of potential instruments.  As such, we were interested in the recent report that compared Plusoptix photoscreener to orthoptic exam in early primary school children, reporting 100% specificity but relatively low sensitivity: “the sensitivity of the PVS to detect amblyopia-associated f...

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  American pediatricians, armed with a new reimbursement code for photoscreening young children (99174), are very interested in the validity of potential instruments.  As such, we were interested in the recent report that compared Plusoptix photoscreener to orthoptic exam in early primary school children, reporting 100% specificity but relatively low sensitivity: “the sensitivity of the PVS to detect amblyopia-associated factors is 44%, with 95% CI from 28 to 62%. Even a sensitivity of 62% would be less than desirable for a standalone screening test”[1]  We are concerned the methodology and terminology for “sensitivity” differs from what many pediatricians might expect. From Table 3, it appears the PlusOptix was able to detect most refractive errors but underestimated cycloplegic hyperopia and strabismus.  We ask that the authors report their results by using pre-defined pediatric ophthalmology risk levels (ref 10) and clarify the limited number of their subject who actually completed the cycloplegic examination which others consider the gold standard[2]. Plusoptix allows users to pre-define age-based referral cut offs for various  amblyopia risk factors.  We wonder why the authors chose their PlusOptix cutoffs that differed from an attempt to calibrate the instrument in reference 21?[3] Furthermore we wonder if changing the cutoff for hyperopia may increase the accuracy of the device. It may be worthwhile to re-analyze this original cohort to see if the sensitivity would improve. It would also be worth noting how the gold standard orthoptic vision screening compares to a dilated cyclopleged examination by a pediatric ophthalmologist, as comparing the Plusoptix to a comprehensive ophthalmology examination may change the reliability. Orthoptists are ideally trained to provide an accurate pediatric vision screening on children, however in certain countries, such as the United States of America, with a population of approximately 305 million people and only approximately 300 orthoptists more efficient methods of pediatric vision screenings must be discovered and refined. In recent population studies the prevalence of childhood amblyopia, primarily comprised of refractive error and manifest esotropia,  is about 2.5%[4].  If an acceptable screening technique has false positive rate less than 1/3, then the ideal referral rate should be about 4%, much closer to the PlusOptix compared to 12.5% for orthoptic screening.  The author’s “gold standard” orthoptic screening has merit, but probably has low predictive value for amblyopia screening.

  Robert W. Arnold, MD
  Noelle Matta CO, CRC, COT, Orthoptist
  Members of the Vision Screening Committee of AAPOS  

  References

  1. Dahlmann-Noor A, Vrotsou K, Kostakis V, et al. Vision screening in Children by Plusoptix Vision Screener compared with gold standard orthoptic assessment. Br J Ophthalmol 2008;92:e-pub.
  2. Donahue S, Arnold R, Ruben JB. Preschool vision screening: What should we be detecting and how should we report it?  Uniform guidelines for reporting results from studies of preschool vision screening. J AAPOS 2003;7:314-6.
  3. Clausen MM, Arnold RW. Pediatric Eye/Vision Screening: Referral Criteria for the PediaVision PlusOptix S04 Photoscreener Compared to Visual Acuity & Digital Photoscreening: “Kindergarten Computer Photoscreening”. Binoc Vis and Strabismus Quart 2007;22:83-9.
  4. MEPEDS. Prevalence of amblyopia and strabismus in African American and Hispanic children ages 6 to 72 months the multi-ethnic pediatric eye disease study. Ophthalmology 2008;115:1229-36 e1.

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  Conflict of Interest:
  None declared.

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