***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: OBJECTIVE To compare the ability of pediatric residents to differentiate an asymmetric from a symmetric red reflex in patients with anisometropia and microstrabismus using the Brückner reflex and the Medical Technology Innovations ( MTI ) photoscreener . METHODS A prospect i ve , masked , case-control study was performed . Twelve pediatric residents evaluated 10 study patients and 6 control subjects in a masked manner in 2 separate sessions , using the Brückner reflex or the MTI photoscreener , evaluating for asymmetric ( abnormal ) or symmetric ( normal ) red reflexes between the 2 eyes . Each study patient had asymmetric red reflexes and the amblyogenic risk factor of anisometropia or microstrabismus . Each control subject had symmetric red reflexes . RESULTS The pediatric residents had a mean correct score of 82 % ( 69%-100 % ) using the MTI photoscreener versus a mean correct score of 65 % ( 44%-81 % ) using the Brückner reflex ( McNemar test : alpha < 0.01 ) . The sensitivity of the MTI photoscreener evaluation was 89 % in comparison to 61 % for the Brückner reflex . The specificities for the MTI photoscreener versus the Brückner reflex were similar at 69 % and 71 % , respectively . CONCLUSIONS Pediatric residents were better at detecting asymmetric red reflexes in patients with anisometropia and microstrabismus when evaluating MTI photoscreener photographs than when evaluating the red reflexes by the Brückner reflex . The MTI photoscreener may be a more sensitive method than the Brückner reflex to screen for the common amblyogenic risk factors of anisometropia and microstrabismus by easier detection of red reflex asymmetry PURPOSE To evaluate the diagnostic accuracy of the plusoptiX S04 digital photoscreener in a school screening program . METHODS Between 2006 and 2007 , 1343 information pamphlets/consent forms were sent to all junior kindergarten students in a local school district . Assistants from a local public health unit photographed 307 children . Of these , 271 children received an independent ophthalmic examination by a physician . Photographic results were compared with the those of the ophthalmic examination .  Amblyopia risk factors were defined as anisometropia > 1 D ( sphere or cylinder ) , astigmatism > 1.25 D , myopia > 3 D , hyperopia > 3.5 D , any manifest strabismus , and any media opacity . RESULTS Photographic and examination results agreed in 94 % of cases . Sensitivity in detecting amblyopia risk factors was 83 % ; specificity was 95 % . The positive and negative predictive values were 73 % and 97 % , respectively . The untestable/unusable rate was 1 % . CONCLUSIONS These results compare favorably with a previously reported ( but no longer available ) digital photoscreening camera and are superior to results obtained with other off-axis photoscreening devices that require human interpretation . On the basis of these results , in a real-world screening program , the camera would falsely refer 4 % of those screened and would fail to correctly refer 2 % . The accuracy of the plusoptiX S04 camera in detecting amblyopia risk factors appears sufficiently high to consider its further deployment in a widespread school screening program Aim To evaluate the efficacy of the three-dimensional ( 3D ) Strabismus Photo Analyzer for estimating binocular alignment using photographs . Methods Thirty-two subjects with exotropia , 30 subjects with esotropia and 38 orthotropic subjects were included . Two independent ophthalmologists examined the angle of deviation using the Krimsky test and prism and alternate cover test ( PCT ) . Full-face photographs were obtained using an 8.2-megapixel digital single-lens reflex camera , and the images were analysed using the 3D Strabismus Photo Analyzer . The images were adjusted for age-dependent ophthalmic biometry and angle κ . The main outcome measures were inter-observer variability , test‐retest reliability and correlation between the angles of deviation measured by different methods . Results The 95 % limit of agreement of inter-observer variability was ±3.5 ° ( 6.1 prism dioptres ( PD ) ) , ±3.1 ° ( 5.4 PD ) and ±1.5 ° ( 2.6 PD ) for the Krimsky test , PCT and the 3D Strabismus Photo Analyzer , respectively . The test‐retest reliability was ±2.8 ° ( 4.9 PD ) for the 3D Strabismus Photo Analyzer versus the Krimsky test . The results of the Krimsky test and 3D Strabismus Photo Analyzer showed a strong positive correlation . Conclusions The 3D Strabismus Photo Analyzer is a simple and reliable tool for measuring ocular deviation . It has excellent agreement with the Krimsky test and substantially improved reproducibility The primate visual cortex , including that of man , receives separate input from each eye and these interact in binocular cortical neurones . This organization is known to be vulnerable to disruption in early life1 . To underst and the development of human visual cortex , and to detect and assess disorders of binocular function at the earliest possible age , a robust method is needed for detecting binocular interactions in the infant 's visual system . We have done this by recording cortical visual evoked responses ( VERs ) to the onset and offset of binocular correlation in a large-screen dynamic r and om dot display . We report here that , in general , the human infant has a functional binocular visual cortex by 3 months of age , with some individuals showing cortical binocularity at an earlier age A Cochrane review of literature from 1966 to 2004 on screening for correctable visual acuity defects in school-aged children and adolescents found “ no robust trials available that allow the benefits of school vision screening to be measured . The disadvantage of attending school with a visual acuity deficit also needs to be quantified . The impact of a screening program will depend on the geographical , and the socio-economic setting in which it is conducted ” [ 2 ] . However , major refractive errors can occur in 5 % to 7 % of preschoolers [3][4 ] ; individual r and omized , longitudinal studies report that early screening has been associated with a decrease in the prevalence of amblyopia and improved acuity by 60 % [ 5 ] . Screening before three years of age is associated with a 70 % lower prevalence of amblyopia after treatment [4][6 ] . The single and most effective test for amblyopia is the determination of visual acuity by noninvasive testing . A Cochrane review on screening specifically for amblyopia ( 1966 to 2005 ) concluded that “ the lack of data from r and omized controlled trials makes it difficult to analyze the impact of screening programs on the prevalence of amblyopia . The absence of such evidence can not be taken to mean that vision screening is not beneficial ; simply that this intervention has not yet been tested in robust studies ” [ 7 ] . Adverse effects on educational and social development , as well as limitations to career choice are obvious consequences of poor visual acuity . Uncorrected amblyopia is a significant risk factor for total blindness , in the case of injury or disease , in the better functioning eye . The American Academy of Ophthalmology and the American Academy of Pediatrics [ 6 ] recommend visual assessment from birth and at all routine health supervisory visits . The child ’s anatomy and function should be checked at regular infant and well-child visits , and visual acuity should be assessed at the preschool stage as well as when there is a complaint . Infants with a known risk ( retinopathy of prematurity , Down ’s syndrome , etc ) or significant family history ( congenital glaucoma , strabismus ) should be referred for further evaluation [ 6 ] PURPOSE To compare 11  preschool vision screening tests  administered by licensed eye care professionals ( LEPs ; optometrists and pediatric ophthalmologists ) . DESIGN Multicenter , cross-sectional study . PARTICIPANTS A sample ( N = 2588 ) of 3- to 5-year-old children enrolled in Head Start was selected to over-represent children with vision problems . METHODS Certified LEPs administered 11 commonly used or commercially available screening tests . Results from a st and ardized comprehensive eye examination were used to classify children with respect to 4 targeted conditions : amblyopia , strabismus , significant refractive error , and unexplained reduced visual acuity ( VA ) . MAIN OUTCOME MEASURES Sensitivity for detecting children with > or = 1 targeted conditions at selected levels of specificity was the primary outcome measure . Sensitivity also was calculated for detecting conditions grouped into 3 levels of importance . RESULTS At 90 % specificity , sensitivities of noncycloplegic retinoscopy ( NCR )  ( 64 % ) , the  Retinomax Autorefractor  ( 63 % ) ,  SureSight Vision Screener ( 63 % ) , and Lea Symbols test ( 61 % ) were similar . Sensitivities of the Power Refractor II ( 54 % ) and HOTV VA test ( 54 % ) were similar to each other . Sensitivities of the R and om Dot E stereoacuity ( 42 % ) and Stereo Smile II ( 44 % ) tests were similar to each other and lower ( P<0.0001 ) than the sensitivities of NCR , the 2 autorefractors , and the Lea Symbols test . The cover-uncover test had very low sensitivity ( 16 % ) but very high specificity ( 98 % ) . Sensitivity for conditions considered the most important to detect was 80 % to 90 % for the 2 autorefractors and NCR . Central interpretations for the MTI and iScreen photoscreeners each yielded 94 % specificity and 37 % sensitivity . At 94 % specificity , the sensitivities were significantly better for NCR , the 2 autorefractors , and the Lea Symbols VA test than for the 2 photoscreeners for detecting > or = 1 targeted conditions and for detecting the most important conditions . CONCLUSIONS Screening tests administered by LEPs vary widely in performance . With 90 % specificity , the best tests detected only two thirds of children having > or = 1 targeted conditions , but nearly 90 % of children with the most important conditions . The 2 tests that use static photorefractive technology were less accurate than 3 tests that assess refractive error in other ways . These results have important implication s for screening preschool-aged children Stereoscopic depth perception was tested in human infants by a new method based on attracting the infant 's attention through movement of a stereoscopic contour formed from a dynamic r and om-element stereogram . The results reveal that stereopsis emerges at 3 1/2 to 6 months of age , an outcome consistent with evidence for rapid postnatal development of the visual system PURPOSE To assess the accuracy of the Lang II stereotest in screening for strabismus , amblyopia , and anisometropia in 6-year-old children . DESIGN Cross-sectional population -based study . METHODS The Sydney Myopia Study examined 1765 6-year-old children ( 78.9 % of eligible ) who were identified by r and om cluster sampling of 34 schools in Sydney , Australia . Sensitivity and specificity of the Lang II stereotest was determined by best stereoacuity .  Cycloplegic autorefraction , assessment of visual acuity , and ocular motility were conducted . RESULTS Test sensitivity ranged from 21.4 % for anisometropia ( > or = 1.0 diopter ) to 31.3 % for amblyopia . The detection rate for new cases of amblyopia ranged from 20 % to 40 % ; the detection rate for new cases of strabismus was 30 % . Specificity was > 98 % in all three conditions . Children with false-negative results included newly diagnosed cases of strabismus ( 14 of 25 children ) or amblyopia ( 5 of 12 children ) . CONCLUSION The Lang II stereotest , when used alone , has very limited value as a screening test of binocular dysfunction Purpose To determine the efficacy of distance stereotesting as a screening device . Methods Distance stereoacuity using the global R and om Dot and contour Circle test of the Mentor BVAT II-SG computerized testing system was measured for 216 patients , ages 6 to 18 years , before the clinical examination . Patients were classified into pass/fail groups in the areas of refractive error change ( REC ) , ocular deviation ( DEV ) , visual acuity ( VA ) , and all three together ( EXAM ) . Legitimate cutoff scores were obtained when patients were classified as ‘ pass ’ as follows : REC if the change was 0.50 D or less in sphere or cylinder relative to the habitual correction or to emmetropia if no habitual correction ; DEV if there was no heterophoria or strabismus at distance ( criteria of heterophoria of < 6 prism diopters and heterophorias of any magnitude were also tested ) ; VA if the acuity at distance was better than or equal to 20/25 in the poorer eye and better than or equal to 20/20 in the better eye ; EXAM if they were pass in REC , DEV , and VA . Optimal pass/fail cutoff values for the stereopsis measurements were determined by finding the maximum & khgr;2 value from contingency tables constructed using pass/fail levels for the screening test at each of the observed levels . Results The pass rates for REC , DEV , VA , and EXAM were 45 % , 72 % , 42 % , and 24 % , respectively . Patients passed the B 
    Output:
    
There is very limited data in the literature to ascertain the accuracy of tests for detecting strabismus in the community as performed by non-expert screeners .