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Screening for amblyopia in preverbal children: improved grading criteria for hyperopia

2001; Elsevier BV; Volume: 108; Issue: 10 Linguagem: Inglês

10.1016/s0161-6420(01)00709-6

1549-4713

Sean P. Donahue, Tammy Johnson, Lawrence M. Merin,

Retinopathy of Prematurity Studies

We were quite pleased to see the report from Tong et al (Ophthalmology 2000;107:1630–6) suggesting a new set of grading criteria for hypermetropia. This is of particular interest to us given our grading criteria for hypermetropia, which we established and reported in the companion article1Donahue S.P Johnson T.M Leonard-Martin T.C Screening for amblyogenic factors using a volunteer lay network and the MTI PhotoScreener. Initial results from 15,000 preschool children in a statewide effort.Ophthalmology. 2000; 107 (discussion 1645–6): 1637-1644Abstract Full Text Full Text PDF PubMed Scopus (78) Google Scholar to Tong. Tong’s article reports the sensitivity of referral guidelines for detecting hypermetropia greater than 3.5 diopters. In their report, the presence of a bright crescent at two meridians has a sensitivity of 100%, whereas the presence of a bright crescent at three meridians has sensitivity of 75%. However, the latter criteria is based on a very small sample.Theoretically, astigmatism and off-axis fixation (child not looking at the camera) can each produce a bright crescent in two meridians. We have found this to be a problem with our vision-screening program, because our predictive value positive for astigmatism (a bright crescent in two hyperopic meridians) is in the neighborhood of 40%. We believe the presence of a bright crescent in at least three meridians will be much more specific and equally sensitive. Requiring a crescent in three meridians eliminates the likelihood of astigmatism masking as hypermetropia. In addition, Miller et al (Miller JM, Surachatkumtonekul T, Schwiegerling J, Hall H. Detection of improper fixation in MTI Photoscreening Images. Presented at AAPOS meeting, Toronto, Canada, April 1999) have demonstrated that slightly off-axis fixation can produce crescents that seem similar to those seen in hypermetropia. The requirement for the presence of a bright crescent in three meridians would markedly decrease the false-positive referrals for off-axis fixation.We compliment Tong and his colleagues for recognizing these potential new grading criteria and are in the process of beginning an analysis of our data to compare the predictive value positive for a bright crescent in three meridians to our criteria. We were quite pleased to see the report from Tong et al (Ophthalmology 2000;107:1630–6) suggesting a new set of grading criteria for hypermetropia. This is of particular interest to us given our grading criteria for hypermetropia, which we established and reported in the companion article1Donahue S.P Johnson T.M Leonard-Martin T.C Screening for amblyogenic factors using a volunteer lay network and the MTI PhotoScreener. Initial results from 15,000 preschool children in a statewide effort.Ophthalmology. 2000; 107 (discussion 1645–6): 1637-1644Abstract Full Text Full Text PDF PubMed Scopus (78) Google Scholar to Tong. Tong’s article reports the sensitivity of referral guidelines for detecting hypermetropia greater than 3.5 diopters. In their report, the presence of a bright crescent at two meridians has a sensitivity of 100%, whereas the presence of a bright crescent at three meridians has sensitivity of 75%. However, the latter criteria is based on a very small sample. Theoretically, astigmatism and off-axis fixation (child not looking at the camera) can each produce a bright crescent in two meridians. We have found this to be a problem with our vision-screening program, because our predictive value positive for astigmatism (a bright crescent in two hyperopic meridians) is in the neighborhood of 40%. We believe the presence of a bright crescent in at least three meridians will be much more specific and equally sensitive. Requiring a crescent in three meridians eliminates the likelihood of astigmatism masking as hypermetropia. In addition, Miller et al (Miller JM, Surachatkumtonekul T, Schwiegerling J, Hall H. Detection of improper fixation in MTI Photoscreening Images. Presented at AAPOS meeting, Toronto, Canada, April 1999) have demonstrated that slightly off-axis fixation can produce crescents that seem similar to those seen in hypermetropia. The requirement for the presence of a bright crescent in three meridians would markedly decrease the false-positive referrals for off-axis fixation. We compliment Tong and his colleagues for recognizing these potential new grading criteria and are in the process of beginning an analysis of our data to compare the predictive value positive for a bright crescent in three meridians to our criteria.