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Nurses, lay screeners achieved similar sensitivity in detecting vision problems in children
Additional outcomes of the Vision in Preschoolers Study found which screening tests work best in detecting childhood vision problems.
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Nurses and lay screeners achieved similar levels of sensitivity using several different methods when screening preschoolers for amblyopia, strabismus and refractive errors, according to outcomes from the Vision in Preschoolers Study.
Phase 2 data from the VIP study, released initially at the meeting of the Association for Research in Vision and Ophthalmology (ARVO) and published in the August issue of Investigative Ophthalmology & Visual Science, found that nurses and non-health care personnel achieved similar results for detecting children in need of a comprehensive eye examination, when screening parameters were set at 0.90 specificity.
“At 0.90 specificity, sensitivity for detection of the targeted conditions of greatest severity (eg, severe anisometropia, constant strabismus, hyperopia > 4.75 D, astigmatism > 2.25 D, myopia > 5.75 D) did not differ between nurse screeners and lay screeners,” according to the abstract for the ARVO presentation. Screening tools were used to detect the four major childhood vision problems — amblyopia, strabismus, significant refractive error and unexplained reduced visual acuity.
Additional analyses of the results of phase 1 of the VIP Study, also presented at ARVO, compared 11 screening tools for their sensitivity – their ability to identify “true positives” in children with visual disorders – when set at a high specificity rate of 94% to rule out false positives.
Echoing outcomes reported in phase 1 of VIP when specificity was set at 90%, study investigators found that the screening tests “vary widely” in sensitivity. However, they determined that four screening tools may be more successful than other screening methods in detecting vision problems and therefore may be more appropriate for screening programs.
Methods
Phase 1 of VIP evaluated and compared the efficacy of screening tools when used in a highly controlled environment by ophthalmologists and optometrists. In phase 2, investigators evaluated the effect of a subset of the tools in a less controlled environment in which nurses or lay people experienced in working with young children conducted the screenings.
All screeners underwent training and certification with the screening tests prior to screening the 1,452 children who participated in phase 2 of the study. Preschoolers age 3 to 5 years from five different Head Start programs underwent screening tests with either the Retinomax K-plus 2 autorefractor (Right Medical Products), the SureSight Vision Screener (Welch Allyn), crowded linear Lea Symbols at 3 m or crowded single Lea Symbols at 1.5 m (Good-Lite), and the Stereo Smile II test (Stereo Optical).
In phase 1 of the study, 2,588 preschoolers were screened with additional screening devices, including noncycloplegic retinoscopy, the MTI PhotoScreener (Medical Technologies), the iScreen Photoscreener (iScreen Inc.), Power Refractor II (Plusoptix), random dot E stereoacuity test (Stereo Optical) and the cover-uncover test.
Screening outcomes were compared to comprehensive eye examinations, which appropriately classified all study children with vision disorders.
Screener efficacy
Screening results were obtained for more than 98% of children in phase 2. Overall, detection of the study’s four targeted conditions did not differ between lay screeners and nurses.
When comparing the types of screening tools and their ability to detect the conditions, the study authors reported that sensitivities were “very similar” for lay screeners and nurse screeners when using the SureSight Vision Screener and Stereo Smile II test, but they “differed slightly” when using the Retinomax autorefractor and crowded linear Lea Symbols.
Investigators found that sensitivity was “significantly higher” for lay screeners when using the crowded single Lea Symbols at 1.5 m compared with nurse screeners who used the crowded linear Lea Symbols at 3 m.
Device efficacy
In phase 1 of the study, researchers determined which screening tools were most sensitive in detecting each of the targeted conditions when specificity was set at 94%. Results when the specificity was set at 90% were presented previously and showed that noncycloplegic retinoscopy, the Retinomax, SureSight and Lea Symbols visual acuity test had the highest sensitivity when the goal was to detect children with one or more of the targeted vision conditions.
Noncycloplegic retinoscopy was found to be most sensitive in detecting amblyopia (88%), followed by screening with the SureSight (80%) and the Retinomax (78%). The MTI PhotoScreener was found to detect strabismus most accurately (65%), followed by the cover-uncover test (60%), the Stereo Smile II test (58%), the SureSight (54%) and the Retinomax (53%).
“The most accurate tests for detecting significant refractive error were noncycloplegic retinoscopy [74%], the Retinomax [66%], the SureSight [63%] and Lea Symbols [48%],” the researchers reported.
Lea Symbols testing was the most accurate tool for detecting reduced visual acuity (48%) followed by the Retinomax (39%) and noncycloplegic retinoscopy (38%).
For Your Information:References:
- Paulette S. Schmidt, OD, MS, principal investigator of the VIP Study, can be reached at The Ohio State University College of Optometry, P.O. Box 183242, Columbus, OH 43218-2342; 614-292-3189; fax: 614-247-6907; e-mail: schmidt.13@osu.edu.
- Graham E. Quinn, MD, MSCE, a member of the VIP Study Group, can be reached at 1st Floor, Wood Center, The Children’s Hospital of Philadelphia, Philadelphia, PA 19104; 215-590-2791; fax: 267-426-5015; e-mail: quinn@email.chop.edu.
- Moore BD and Vision in Preschoolers (VIP) Study Group. Sensitivity of screening tests for detecting VIP-targeted vision disorders when specificity is 94%. Invest Ophthalmol Vis Sci. 2005;46:E-Abstract 2355.
- Schmidt PP, Dobson V and Vision in Preschoolers (VIP) Study Group. Vision in Preschoolers (VIP) Study: results of phase II. Invest Ophthalmol Vis Sci. 2005;46:E-Abstract 2354.
- Vision in Preschoolers Study Group. Comparison of preschool vision screening tests as administered by licensed eyecare professionals in the Vision in Preschoolers (VIP) Study. Ophthalmology. 2004;111(4):637-650.
- Vision in Preschoolers Study Group. Preschool vision screening tests administered by nurse screeners compared to lay screeners in the Vision in Preschoolers Study. Invest Ophthalmol Vis Sci. In press.
- Nicole Nader is an OSN Correspondent based in Philadelphia.