text: Ocular Photoscreening as a Screening Tool to Detect Amblyogenic Factors
  Amblyopia is a disorder of visual development, manifested as decreased visual acuity in one eye. It affects more than 2% of the population, and is the leading cause of monocular vision loss in children and adults. However, if detected before eight to ten years of age, it can be effectively treated by occlusion of the sound eye. A variety of organizations have recommended routine vision screening throughout childhood. The following organizations have recommended routine vision screenings throughout childhood:
  American Academy of Pediatrics (AAP), U.S. Preventive Services Task Force, American Academy of Ophthalmology (AAO), American Optometric Association (AOA), American Association for Pediatric Ophthalmology and Strabismus (AAPOS).
  Detection of amblyopia itself requires assessment of visual acuity, which is difficult in preverbal children. Ocular photoscreening has been investigated as an alternative screening method, not to detect amblyopia itself, but instead to detect risk factors for amblyopia, which include strabismus, high refractive errors, anisometropia, and media opacities.
  Ocular photoscreening is based on the principle of photorefraction in which the refractive state of the eye is assessed via the pattern of light reflected through the pupil. The images can then be analyzed based on the position of the corneal light reflex as well as the overall reflection of light from the fundus, which provides information on the child's fixation pattern and the presence or absence of strabismus. Patients are photographed in a darkened room while looking at the camera. The photographs can be sent to a central laboratory for analysis, either by ophthalmologists or specifically trained personnel. Results are typically graded as pass, fail, or repeat photoscreening.
  NOTE: Ocular photoscreening can be performed in several settings. For example, photoscreening can be performed in public health setting or as part of school screening programs. In addition, photoscreening may be performed by ophthalmologists as an adjunct to an ophthalmologic exam. This policy only addresses the use of photoscreening in the setting of the primary care physician's office, where it is performed as an adjunct or alternative to the standard visual exam. It is anticipated that the results of photoscreening would be used by the primary care physician to determine whether the patient required referral to a pediatric ophthalmologist for further evaluation.
  Blue Cross and Blue Shield of Montana (BCBSMT) considers ocular photoscreening experimental, investigational and unproven as a screening tool to detect amblyogenic factors.
  As noted in the Description, this policy only addresses ocular photoscreening when performed in the primary care physician's office, either as an adjunct or alternative to standard visual assessment. Aside from assessment of visual acuity using Snellen charts, letters, or other techniques, primary care physicians typically assess fixation and following movements and perform the red reflex test. Specifically, the red reflex test can detect visual opacities in the visual axis and abnormalities of the back of the eye, such as retinoblastoma or retinal detachment. When the red reflex is assessed simultaneously, potentially amblyopic conditions, such as asymmetric refractive errors and strabismus, can also be identified. The test is performed in a darkened room, with the direct ophthalmoscope focused on each pupil individually and then both eyes simultaneously. The family and clinical history may also identify a child at higher risk of amblyopia. For example, high-risk children include those with a family history of strabismus, amblyopia, high refractive errors, or childhood eye disorders. Children born prematurely, or those with neurologic and developmental conditions, are also at higher risk.
  It is assumed that the results of photoscreening would be used to prompt referral to an ophthalmologist for further evaluation. Therefore, assessment of photoscreening in this setting requires population-based studies to determine whether the results of photoscreening result in a higher referral rate to ophthalmologists, with an associated improvement in sensitivity and specificity for detection of amblyogenic factors that lead to earlier diagnosis and treatment with a decrease in vision-impairing amblyopia. To date, these studies have not been performed.
  The majority of the published studies have focused on the technical feasibility of ocular photoscreening, setting diagnostic parameters for interpretation of the photographs and its use in public health settings. For example, Tong and colleagues from the Wilmer Eye Institute published a series of three studies of the MTI PhotoScreener. The first study of 100 children was designed to determine whether or not healthcare professionals or lay volunteers could interpret and grade photoscreening photographs. A total of 18 volunteers including both pediatric ophthalmologists and lay personnel interpreted the photoscreening results, which included 26 children with normal ophthalmologic exams and 74 with abnormalities. Results from the graders varied, with sensitivities ranging from 37–88% and specificity from 40–80%. No single grader achieved both sensitivity and specificity greater than 70%. The authors concluded that these results reflected either inconsistent photographic interpretation skills or deficient grading criteria.
  A subsequent study was published in 2000, which included 392 preverbal children who were referred to an ophthalmologist for examination; 103 had normal examination findings, while the remaining 284 children had conditions of interest for pediatric screening. In this study, the photographs were graded by a representative of the manufacturer, MTI PhotoScreener™, and the results compared with the results of the ophthalmologic exam. The overall sensitivity was 65% and the specificity 87%. The results were further analyzed according to the abnormality present, i.e., external examination abnormality (e.g., ptosis), media opacity, strabismus, and refractive error. The sensitivity for refractive error was low (33%), while the sensitivity for strabismus was 55%. The authors conclude that while photoscreening with the MTI system is promising, further research on grading criteria, particularly to detect refractive errors, is needed. The third study by the Wilmer Eye Institute investigated a new grading system for hyperopia, based on the conclusions from the previous study that the criteria for hyperopia indicating a failing grade were too low and would result in an undesirably high referral rate. This study re-examined the 392 photographs from the previous study and developed new grading criteria that resulted in a sensitivity and specificity of 100% and 88%, respectively.
  Simons and colleagues studied the MTI PhotoScreener™ in 100 children, aged four months to twelve years, who were recruited either from a pediatric ophthalmologic referral practice or a day care center, or who were suspected to have developmental delay or a behavior disorder. All 100 photographs were independently graded by six observers, including four pediatric ophthalmologists, a nurse, and a research coordinator, and compared to the results of a complete ophthalmologic examination. For detecting any abnormal results, the sensitivity ranged from 80–91% and the specificity ranged from 20–67%. This study included verbal children, who presumably could participate in visual acuity tests.
  It should be noted that all of the above studies recruited patients from a pediatric ophthalmology practice or other settings such that the studied population had a high incidence of patients with pathologic conditions. While these populations are useful to determine the initial sensitivity of photoscreening, this population does not duplicate the general population of children presenting to the primary care physicians' office. Presumably, the patients in the above studies were referred to a pediatric ophthalmologist due to a clinical abnormality noted in the physical exam or a history that placed them at high risk. To determine the utility of photoscreening in the primary care physician's office, the sensitivity and specificity of the photoscreening should be compared to the sensitivity and specificity of clinical diagnosis in this setting.
  Ocular photoscreening has also been investigated in a public health care setting, where presumably the photoscreening is the only type of vision screening that is available to participants. For example, Donahue and colleagues reported on the results of a public health screening program that evaluated 15,000 preschool children in Tennessee. This program used volunteers from local Lions Clubs to take the photographs, and all photographs were interpreted at a central reading station by professional photo readers. The positive predictive value ranged from 84% when a diagnosis of strabismus was suggested by the photoscreen to 41% for astigmatism. While this public health setting is not applicable to this policy, it is anticipated that ocular photoscreening may be predominantly used in this setting.
  In 2002, the American Academy of Pediatrics (AAP) published a commentary on photoscreening. This document noted the following:
  Photoscreening does not represent a single technique or piece of equipment. Different optical systems can be used for photoscreening. Interpretation of screened images may be performed in the physician's office, office in a reading center, or with an automated system. Each photoscreening system may have its own advantages and disadvantages, and it appears that results published in the literature for one system are not necessarily valid for others. It is difficult to compare efficacies of various vision-screening methods, such as stereoacuity testing, autorefraction, red reflex testing and cover testing, and then determine if photoscreening has better positive and negative predictive values. This is attributable in part to a lack of uniformity in pass-fail criteria for significant refractive errors. Photoscreening needs to be studied more extensively. The AAP favors additional research of photoscreening devices and other vision-screening methods in large, controlled studies to elucidate validity of results, efficacy, and cost effectiveness to identify amblyogenic factors in different age groups as well as subgroups of children.
  In 2003, the AAP issued a policy statement on eye examination as performed by pediatricians, which included discussion of ocular photoscreening. This document noted that "photoscreening is not a substitute for accurate visual acuity measurement but can provide significant information about the presence of sight threatening conditions such as strabismus, refractive errors, media opacities (cataract) and retinal abnormalities (retinoblastoma). Photoscreening techniques are still evolving."
  In 2003, AAPOS published a position statement on photoscreening, which reads in part, "It is important to remember that photoscreening detects many problems that predispose the developing visual system to amblyopia, rather than providing a direct test of visual acuity and binocularity, and that, therefore these latter tests are preferable once a child can cooperate with such testing. For the preliterate child, however, photoscreening systems show significant potential. Current photoscreeners still suffer from relatively low sensitivity, high false positive referral rates, and relatively high usage costs. Advances in technology will eventually lead to the development of systems having higher sensitivities and positive predictive values. AAPOS encourages the development of such systems. We believe that further research may produce systems that have sufficient reliability to achieve widespread acceptance and usage, not only for children who do not receive primary medical care, but also in the primary care physician's office."
  A literature search performed for the period of 2004 through July 2007 did not identify any additional published literature that would prompt reconsideration of the policy statement, which remains unchanged. The published literature continues to focus on settings other than the primary care physician's office, i.e., a public health setting or an ophthalmology clinic. In 2005, a Cochrane review focused on the role of screening for amblyopia in general and noted that there have been no trials comparing the prevalence of amblyopia in screened vs. unscreened trials, therefore it is difficult to analyze the impact of screening programs on the prevalence of amblyopia. A single study was identified that examined the use of photoscreening in the primary care setting. Kemper and colleagues conducted a national survey of 377 pediatricians (55% response) to determine the rate of acuity screening in preschool children. It was reported that vision screening was conducted in 35%, 73%, and 66%, of three, four, and five-year olds, respectively. Few (8%) of the respondents reported using either autorefraction or photoscreening. Based on a retrospective review, Donahue reported that younger children with anisometropia had a lower prevalence of amblyopia than older children. This retrospective study, which should be considered preliminary, suggests that earlier detection of anisometropia might allow earlier intervention, and may prevent or retard development of amblyopia.
  The National Eye Institute is sponsoring a three-phase multicenter prospective clinical trial to evaluate screening tests for identifying preschool children in need of comprehensive eye examinations. The category of screening personnel and the specific screening tests will be determined in Phases I and II of the "Vision in Preschoolers (VIP) Study". Phase III will evaluate the performance (sensitivity and specificity) of the tests in identifying specific vision disorders in 6400 Head Start preschoolers.
  Procedural Codes: 99174
  Tong, P.Y., Enke-Miyazaki, E., et al. Screening for amblyogenic in preverbal children with photoscreening photographs. National Children's Eye Care Foundation Vision Screening Study Group. Ophthalmology (1998 May) 105(5):856-63.
  Ottar, W.L., Scott, W.E., et al. Photoscreening for amblyogenic factors. Journal of Pediatric Ophthalmology and Strabismus (1995 September-October) 32(5):289-95.
  Weinand, F., Graf M., et al. Sensitivity of the MTI PhotoScreener™ for amblyogenic factors in infancy and early childhood. Graefes Archive for Clinical and Experimental Ophthalmology. (1998 November) 236(11):801-5.
  Simons, B.D., Siatkowski, R.M., et al. Pediatric photoscreening for strabismus and refractive errors in a high-risk population. Ophthalmology (1999 June) 106(6):1073-80.
  Enzenauer, R.W., Freeman, H.L., et al. Photoscreening for amblyogenic factors by public health personnel: the Eyecor Camera System. Ophthalmic Epidemiology (2000 March) 7(1):1-12.
  Eibschitz-Tsimhoni, M., Friedman, T., et al. Early screening for amblyogenic risk factors lowers the prevalence and severity of amblyogenic. Journal of American Association for Pediatric Ophthalmology and Strabismus (AAPOS) (2000 August) 4(4):194-9. R.A.Kennedy, and D.E. Thomas. Evaluation of the iScreen digital screening system for amblyogenic factors. Canadian Journal of Ophthalmology (2000 August) 35(5):258-62.
  Tong, P.Y., Macke, J.P., et al. Screening for amblyogenic in preverbal children with photoscreening photographs. III. Improved grading criteria for hyperopia. Ophthalmology (2000 September) 107(9):1630-6.
  Donahue, S.P., Johnson, T.M., et al. 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 September) 107(9):1637-44; discussion 1645-6.
  J.W.Simon, and P. Kaw. Commonly missed diagnosis in the childhood eye examination. American Family Physician (2001 August 15) 64(4):623-8.
  J.W Simon, Kaw, P., et al. Vision screening performed by the pediatrician. Pediatric Annals (2001 April) 30(8):446-52.
  S.P.Donahue, and T.M. Johnson. Age-based refinement of referral criteria for photoscreening. Ophthalmology (2001 December) 108(12):2309-14; discussion 2314-5.
  M. Dostalek, and A. Benesova. Some recruitment aspects of population photoscreening of amblyogenic factors at children younger one year. Acta Medica (Hradec Kralove) (2002) 45(4):161-6.
  Grossniklaus, H. Sensitivity of photoscreening to detect high-magnitude amblyogenic factors. American Journal of Ophthalmology. (2002) 6:86-91.
  Donahue, S.P., Johnson, T.M., et al. Sensitivity of photoscreening to detect high-magnitude amblyogenic factors. Journal of American Association for Pediatric Ophthalmology Strabismus (2002 April) 6(2):86-91.
  T..Schimitzek, and W. Haase. Efficiency of a video-autorefractometer used as a screening device for amblyogenic factors. Graefes Archive for Clinical and Experimental Ophthalmology (2002 September) 240(9):710-6.
  S.P Donahue, and T.M. Johnson. Screening with photoscreening photographs. Ophthalmology (2004 March) 111(3):604-5.
  Savage, H.I., Lee, H.H., et al. Pediatric Amblyopia Risk Investigation Study (PARIS). American Journal of Ophthalmology (2005) 140(6):1007-13.
  Use of photoscreening for children's vision screening. Committee on Practice and Ambulatory Medicine and Section on Ophthalmology; American Academy of Pediatrics. Pediatrics (2002) 109(3):524-5. (accessible 2007 July 25) www.aappolicy.aappublications.org .
  Kemper, A.R., and S.J. Clark. Preschool vision screening in pediatric practices. Clinical Pediatrics (2006) 45(3):263-6.
  Donahue, S.P. Relationship between anisometropia, patient age, and the development of amblyopia. American Journal of Ophthalmology (2006) 142(1):132-40.
  Vision In Preschoolers Study (VIP Study). Accessible at www.clinicaltrials.gov (accessed June 19, 2007).
  Ocular Photoscreening in the Primary Care Physician's Office as a Screening Tool to Detect Amblyogenic Factors. Chicago, Illinois: Blue Cross Blue Shield Association Blue Web Medical Policy Reference Manual. (2007 August) Vision 9.03.12.
  June 2013 New 2013 BCBSMT medical policy. Ocular photoscreening is considered experimental, investigational and unproven as a screening tool to detect amblyogenic factors. BCBSMT Home ®Registered marks of the Blue Cross and Blue Shield Association, an association of independent Blue Cross and Blue Shield Plans. ®LIVE SMART. LIVE HEALTHY. is a registered mark of BCBSMT, an independent licensee of the Blue Cross and Blue Shield Association, serving the residents and businesses of Montana.