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Validity of the +1.50 plus lens screening test as a predictor of uncorrected moderate hyperopia
Author(s) -
Hopkins Shelley,
Black Alex A,
White Sonia L,
Wood Joanne M
Publication year - 2019
Publication title -
ophthalmic and physiological optics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.147
H-Index - 66
eISSN - 1475-1313
pISSN - 0275-5408
DOI - 10.1111/opo.12617
Subject(s) - optometry , test (biology) , ophthalmology , refractive error , lens (geology) , medicine , psychology , eye disease , optics , physics , geology , paleontology
Purpose Screening for uncorrected hyperopia in school children is important given its association with poorer visual function and academic performance. However, standard distance visual acuity screening may not detect low to moderate hyperopia. The plus lens test is used to screen for hyperopia in many school screening protocols, but has not been well validated. The current study investigated the effectiveness of the plus lens test to identify hyperopia in school children. Methods Participants included Grade 2 school children. Monocular distance visual acuity (log MAR letter chart) was measured unaided, and then through a +1.50D lens, known as the plus lens test. Cycloplegic refraction was undertaken to classify moderate hyperopia (≥+2.00D). Sensitivity, specificity, positive predictive values ( PPV ) and negative predictive values ( NPV ) were calculated for commonly used cut‐offs for the plus lens test: 6/6, 6/9 and less than two lines difference between unaided acuity and acuity through the plus lens test. Results The sample included 59 children (mean age 7.2 ± 0.4 years). Fourteen (24%) children were classified as having uncorrected hyperopia. The sensitivity and specificity of the +1.50 plus lens test for identifying hyperopia were 0% and 98% respectively for a 6/6 cut‐off, 29% and 91% for 6/9 cut‐off, and 50% and 76% for a <2 line reduction between unaided acuity and acuity through the plus lens test. Receiver Operating Curve ( ROC ) analysis revealed area under curves of 0.69 based on acuity through the plus lens test, and 0.65 for a reduction in acuity through the plus lens test. Conclusions The plus lens test has low sensitivity for detecting uncorrected hyperopia using traditional cut‐offs of 6/9 or better. This raises questions about the role of the plus lens test in school screening batteries.