MTI Photoscreener Research Articles

Practical Community Photoscreening in Very Young Children

Recent US Preventive Services Task Force recommendations on vision screening reported insufficient data to recommend vision screening in children <3 years of age. The Iowa photoscreening program, KidSight, has screened children from 6 months of age and older since 2000. We report our experience with vision screening in these children and compare the results of the photoscreens in children younger than 3 years with those of children of preschool age and older. A retrospective review of results from the Iowa KidSight database using the MTI PhotoScreener containing results of children screened between May 1, 2000, and April 30, 2011. During the 11 years of the study, 210 695 photoscreens on children were performed at 13 750 sites. In the <3-year age group, the unreadable rate was 13.0%, the referral rate was 3.3%, and the overall positive-predictive value was 86.6%. In the 3- to 6-year-old children, the unreadable rate was 4.1%, the referral rate was 4.7%, and the overall positive-predictive value was 89.4%. No statistically significant difference was found in screening children from 1 to 3 years old compared with screening children >3 years old. These results confirm that early screening, before amblyopia is more pronounced, can reliably detect amblyogenic risk factors in children younger than 3 years of age, and we recommend initiation of photoscreening in children aged 1 year and older.

Comparison of the iScreen and the MTI photoscreeners for the detection of amblyopia risk factors in children

The iScreen and Medical Technology and Innovations, Inc, (MTI) photoscreeners objectively screen for amblyopia risk factors in children. The MTI photoscreener has been extensively validated as a device that objectively screens for amblyopia risk factors in children, but limited availability of the instant film it uses may soon render it obsolete. More recently the iScreen photoscreener has been introduced. This device captures images digitally and transmits them electronically to be interpreted. We compared the newer iScreen's ability to detect amblyopia risk factors in children with the established MTI photoscreener. The medical records of consecutive subjects screened by both the iScreen and MTI photoscreeners on the same day were retrospectively reviewed. The iScreen images were analyzed by the device's central interpretation center; MTI images were analyzed by an expert masked examiner using the delta crescent method. Referrals by both instruments were compared to the results of cycloplegic examination as per the American Association for Pediatric Ophthalmology and Strabismus 2003 referral criteria. A total of 169 children were included in the study. Of these, 107 (63%) were found to have amblyopia risk factors. The iScreen was found to have an accuracy rate of 81%, sensitivity of 87%, and specificity of 76%. The MTI was found to have an accuracy rate of 81%, sensitivity of 81%, and specificity of 81%. The iScreen and MTI performed similarly in detecting amblyopia risk factors when compared to a comprehensive pediatric ophthalmology examination.

Nine-year Results of a Volunteer Lay Network Photoscreening Program of 147 809 Children Using a PhotoScreener in Iowa

To present the largest cohort of preschool children screened by the MTI PhotoScreener over a 9-year period from a single, statewide vision screening effort. Cross-sectional study. We included 147,809 children screened between May 1, 2000, and April 30, 2009 by a photoscreening program. Retrospective review of results from the Iowa photoscreening program using the MTI PhotoScreener. The photographs were taken by volunteers from local Lions clubs and sent to the University of Iowa for interpretation. Children who failed the photoscreening were referred to local eye care professionals, who preformed a comprehensive eye evaluation and forwarded the results to the Iowa KidSight program. Number of screenings, referral rate, positive predictive value (PPV), follow-up rate, and associated costs per year are described. Over the 9 years of the continuously operating program, 147,809 children underwent photoscreens to detect amblyopic risk factors at 9746 sites. Because of abnormal photoscreen results, 6247 children (4.2%) were referred. Of the children, 24.3% were evaluated by local ophthalmologists and 76.7% were seen by local optometrists. Between 2000 and 2009, the follow-up rate ranged from a low of 36.1% to a high of 89.5%, with an overall program follow-up rate after the addition of the follow-up coordinator of 81.3%. The overall PPV of the MTI PhotoScreener was 94.2%. Taking into account overall operating budget including salaries and associated costs, the cost of screening 1 child has been reduced to $US9 per child. The addition of a part-time follow-up coordinator to the photoscreening program produced 89.5% follow-up rate when screening 147,809 children for amblyopia risk factors over a 9-year period.

Application of MTI photoscreener in amblyopia of infants

目的 以新的筛查标准探讨眼瞬息图像筛查仪(MTI)摄影筛查技术应用于1～2岁儿童弱视危险因素筛查中的可行性.方法 对1～2岁儿童MTI摄影验光结果 与阿托品眼膏散瞳后人工检影结果 进行比较.结果 MTI摄影验光技术对弱视危险因素筛查敏感性为92.16％,特异性为65％;对MTI摄影筛查阳性的儿童的屈光状态及斜视进行分析,筛查敏感性最高的为近视,最低的为斜视;特异性最高的为屈光参差,最低的为散光.结论 MTI摄影筛查技术作为摄影验光法在幼儿弱视危险因素筛查中具有较高的敏感性,亦可用于流行病学调查。

Comparison of the MTI Photoscreener and the Welch-Allyn SureSight ™ autorefractor in a tertiary care center

The MTI photoscreener (MTI) and the Welch-Allyn SureSight autorefractor are commonly used for preschool vision screening. We compared both of these methods on 100 consecutive patients in a prospective, randomized, masked, clinical trial conducted at a tertiary care center. One hundred patients between 1 and 6 years of age were included in the study. All participants underwent a comprehensive eye examination with cycloplegic refraction. Examination failure analysis was done on the SureSight data using the manufacturer's referral criteria, the Vision in Preschoolers study (VIP) 90% specificity criteria, the VIP 94% specificity criteria, and the referral criteria proposed by Rowatt and colleagues. Data were successfully obtained on 76% of children using the SureSight and 96% with the MTI. The sensitivity and specificity of the SureSight to detect clinically significant amblyogenic factors using the manufacturer's criteria was 96.6 and 38.1%, using the VIP 90% criteria was 79.3 and 64.3%, using the VIP 94% criteria was 67.2 and 69.0%, and using criteria proposed by Rowatt and colleagues was 62.1 and 73.8%. The sensitivity and specificity of the MTI photoscreener was 94.8 and 88.1%, respectively. Using the manufacturer's referral criteria, the SureSight had a sensitivity equal to the MTI photoscreener; however, the specificity was low and over-referrals were anticipated. As specificity levels were increased, a substantial number of children with amblyogenic risk factors were not appropriately identified within our study population..

Photo Screening Around the World: Lions Club International Foundation Experience

Purpose: To describe the use of photoscreening for preschool vision screening in several diverse locations throughout the world. Methods: The MTI photo screener was used to screen pre-verbal children; photographs were interpreted using standard criteria. Results: The Tennessee vision screening program remains successful, screening over 200,000 children during the past 8 years. Similar programs modeled across the United States have screened an additional 500,000 children. A pilot demonstration project in Hong Kong, Beijing, and Brazil screened over 5000 additional children with good success and appropriately low referral rates. Conclusion: Photoscreening can be an appropriate technique for widespread vision screening of preschool children throughout the world.

Does Assessing Eye Alignment along with Refractive Error or Visual Acuity Increase Sensitivity for Detection of Strabismus in Preschool Vision Screening?

Preschool vision screenings often include refractive error or visual acuity (VA) testing to detect amblyopia, as well as alignment testing to detect strabismus. The purpose of this study was to determine the effect of combining screening for eye alignment with screening for refractive error or reduced VA on sensitivity for detection of strabismus, with specificity set at 90% and 94%. Over 3 years, 4040 preschool children were screened in the Vision in Preschoolers (VIP) Study, with different screening tests administered each year. Examinations were performed to identify children with strabismus. The best screening tests for detecting children with any targeted condition were noncycloplegic retinoscopy (NCR), Retinomax autorefractor (Right Manufacturing, Virginia Beach, VA), SureSight Vision Screener (Welch-Allyn, Inc., Skaneateles, NY), and Lea Symbols (Precision Vision, LaSalle, IL and Good-Lite Co., Elgin, IL) and HOTV optotypes VA tests. Analyses were conducted with these tests of refractive error or VA paired with the best tests for detecting strabismus (unilateral cover testing, Random Dot "E" [RDE] and Stereo Smile Test II [Stereo Optical, Inc., Chicago, IL]; and MTI PhotoScreener [PhotoScreener, Inc., Palm Beach, FL]). The change in sensitivity that resulted from combining a test of eye alignment with a test of refractive error or VA was determined with specificity set at 90% and 94%. Among the 4040 children, 157 were identified as having strabismus. For screening tests conducted by eye care professionals, the addition of a unilateral cover test to a test of refraction generally resulted in a statistically significant increase (range, 15%-25%) in detection of strabismus. For screening tests administered by trained lay screeners, the addition of Stereo Smile II to SureSight resulted in a statistically significant increase (21%) in sensitivity for detection of strabismus. The most efficient and low-cost ways to achieve a statistically significant increase in sensitivity for detection of strabismus were by combining the unilateral cover test with the autorefractor (Retinomax) administered by eye care professionals and by combining Stereo Smile II with SureSight administered by trained lay screeners. The decision of whether to include a test of alignment should be based on the screening program's goals (e.g., targeted visual conditions) and resources.

Comparison of the MTI Photoscreener and the Welch-Allyn SureSight™ Autorefractor in a tertiary care center

The MTI Photoscreener (MTI) is commonly used for vision screening. This method is expensive and difficult due to cost and ongoing issues with camera and film availability. The Vision in Preschoolers study (VIP) demonstrated the usefulness of an alternative screening device, the SureSight™ Autorefractor (SSA). We compare both of these methods on 100 consecutive patients in a prospective, randomized, blinded, clinical trial. Methods: One hundred consecutive patients between 1 and 6 years of age were included in the study.

Effectiveness of the Lea Symbols and Random Dot E in a large preschool vision screening program

Introduction: In 2001 the Maternal Child Health Bureau/National Eye Institute Vision Screening (MCHB/NEI) Task Force developed interim recommendations for preschool vision screening. This study sought to define the positive-predictive value of these recommendations in a statewide vision screening program using the Lea Symbols (LS) and Random Dot E (RDE). Methods: With IRB approval, the Vision Initiative for Children (VIC) developed a vision screening training program incorporating the MCHB/NEI recommendations to certify, equip, and support community preschool vision screeners. Acuity testing was conducted with the LS at a critical line of 20/40 for 3-year-olds and 20/30 for 4-year-olds. RDE stereoacuity was done at 40 cm (630 arcsec). Results: Since 2001 the VIC Program has certified 978 lay screeners. 15,267 screening results have been reported on children 36 to 59 months of age. 2841 children failed the vision screen and were referred to a local optometrist or ophthalmologist for examination. 345 examination results were received and reviewed. 55 children (16%) had amblyopia. An additional 176 children (51%) had a significant amblyogenic condition or refractive error sufficient for glasses. The overall positive-predictive value (PPV) was 67%. Discussion: The PPV for screening tests used by trained lay screeners in this study compares favorably to the PPV of 31% for the Welch-Allen SureSight autorefractor and is similar or low compared with the PPV of 66 to 92% for the MTI Photoscreener. Conclusions: Traditional screening with the LS and the RDE achieves a PPV of 67% when used by certified lay screeners and remains a reasonable, inexpensive method for use in large screening programs. Adjusting the passing criteria for one or both of these tests may enhance the PPV, but at the risk of increasing the false-negative value.

Lions Clubs International Foundation Core Four Photoscreening: Results From 17 Programs and 400,000 Preschool Children

Photoscreening programs for preschool vision screening have been promoted by Lions Clubs International Foundation (LCIF) via their 17 Core Four grant project awards since 1999. Results from 15 Core Four grant programs in the United States and one in Taiwan are presented here. Photoscreening was modeled after the Tennessee program and instituted statewide in each area. Programs were given latitude with respect to screening instrument and referral criteria, but a partnering academic institution and medical director were expected. Preschool children were screened by volunteers; referred children were examined by community optometrists and ophthalmologists who returned results to each program's coordinating center. Outcome data included number of children screened, referral rate, follow-up rate, and positive predictive value, which was generally determined using AAPOS-defined vision screening criteria. All but one program used the MTI photoscreener (it chose not to participate); photoscreening referral criteria were standard for 13 programs. Through December 2004, more than 400,000 preschool children had been screened. The referral rate for programs using the MTI photoscreener averaged 5.2% (range, 3.7-12.6%). The predictive value of a positive photoscreen was 80%. Overall, 54% of referred children received follow-up examinations. Follow-up rate was the largest variable: 4 programs, screening nearly 250,000 children, had follow-up rates 70% or greater; 10 programs had follow-up data from fewer than 40% of referred children. Volunteer-led photoscreening programs can be instituted in other locations, including overseas, with high levels of effectiveness. Limitations include the possibility of poor success and variable attention to follow-up.

Sensitivity of Screening Tests for Detecting Vision In Preschoolers-targeted Vision Disorders When Specificity Is 94%

To compare the sensitivity of 11 preschool vision screening tests administered by licensed eye care professionals for the detection of the 4 Vision in Preschoolers (VIP)-targeted vision disorders when specificity is 94%. This study consisted of a sample (n = 2588) of 3- to 5-year-old children enrolled in Head Start programs, 57% of whom had failed an initial Head Start vision screening. Screening results from 11 tests were compared with results from a standardized comprehensive eye examination that was used to classify children with respect to the four VIP-targeted vision disorders: amblyopia, strabismus, significant refractive error, and unexplained reduced visual acuity (VA). With overall specificity set to 94%, we calculated the sensitivity for the detection of each targeted vision disorder. With the overall specificity set to 94%, the most accurate tests for detection of amblyopia were noncycloplegic retinoscopy (NCR) (88% sensitivity), the SureSight Vision Screener (80%), and the Retinomax Autorefractor (78%). For detection of strabismus, the most accurate tests were the MTI Photoscreener (65%), the cover-uncover test (60%), the Stereo Smile II stereoacuity test (58%), the SureSight Vision Screener (54%), and the Retinomax Autorefractor (54% in year 1, 53% in year 2). The most accurate tests for detection of significant refractive error were NCR (74%), the Retinomax Autorefractor (66%), the SureSight Vision Screener (63%), and the Lea Symbols VA test (58%). For detection of reduced VA, the most accurate tests were the Lea Symbols Distance VA test (48%), the Retinomax Autorefractor (39%), and NCR (38%). Similar to the previously reported results at 90% specificity, the screening tests vary widely in sensitivity with specificity set at 94%. The rankings of the sensitivities for detection of the 4 VIP-targeted vision disorders are similar to those with specificity set to 90%.

Sensitivity of photoscreening to detect high-magnitude amblyogenic factors

Purpose: To determine the sensitivity of a unique pupil-size based set of referral criteria of the MTI PhotoScreener(Medical Technology and Innovations, Inc, Cedar Falls, Iowa) to detect high magnitude refractive error. Methods: The photoscreening photographs of 949 preschool children previously analyzedwere reevaluated with the new referral criteria. The original photographs had been obtained from pediatricians' offices and public health and Women, Infants, and Children's (WIC) clinics. The results of this analysis were compared with the gold standard clinical examination and cycloplegic refraction. Sensitivities were calculated for amblyogenic factors based on the magnitude of the refractive error. Results: For 26 patients with anisometropia, the sensitivity to detect anisometropia increased from 46% for +1.25 or greater spherical interocular difference to 100% for +2.50 spherical intraocular difference. For 36 patients with hypermetropia in at least 1 meridian ranging from +3.75 to +7.50 D, sensitivity increased from 53% to detect +3.75 D or greater to 70% for +5.00 D or greater. The sensitivity to detect hypermetropia of +5.75 D or greater was 100%. These criteria detected 82% of patients with astigmatism greater than or equal to +3.00 D, and 100% of patients with astigmatism greater than +3.50 D. Conclusion: It is crucial that screening programs avoid overreferrals caused by high false-positive screening rates. The sensitivity of our new criteria increases with higher magnitude refractive error; patients with moderate and severe amblyogenic factors are almost never missed. While the sensitivity to detect lower magnitude refractive error is poor, the amblyogenic impact of such errors remains to be determined. (J AAPOS 2002;6:86-91)

Screening for Amblyogenic Factors with Use of a Volunteer Lay Network and the MTI PhotoScreener

Screening for Amblyogenic Factors with Use of a Volunteer Lay Network and the MTI PhotoScreener

Screening for Amblyogenic Factors with Use of a Volunteer Lay Network and the MTI Photoscreener

Weissman, Barry A. OD, PhDEditor(s): Sharma, Sanjay MD, MSC(epid); Brown, Melissa M. MD,MN,MBA; Brown, Gary C. MD,MBA Author Information

Screening for amblyogenic factors using a volunteer lay network and the MTI PhotoScreener : Initial results from 15,000 preschool children in a statewide effort

Purpose To describe the results from a statewide preschool vision screening program using the MTI PhotoScreener (Medical Technology and Innovations, Inc., Cedar Falls, IA). Design Cross-sectional study. Participants A total of 15,059 children aged 6 to 47 months enrolled in childcare and preschool settings throughout the state of Tennessee. Methods Volunteers from local Lions Clubs took photoscreening photographs of children in a statewide effort. Photographs were interpreted at the Vanderbilt Ophthalmic Photography Reading Center using predetermined criteria. Children who failed the screening were referred to community ophthalmologists or optometrists who performed a comprehensive evaluation and forwarded the results to the authors. Main outcome measures Referral rate, unreadable rate, and predictive value positive (PVP). Results During the 2 years of the screening program, 15,059 children were screened in 850 screenings. The screening referred 1013 children (6.7%), and 704 photographs (4.7%) were unreadable. Children who failed the screening had a significant abnormality (strabismus, anisometropia, high hypermetropia, high astigmatism, or high myopia) in 320 of the 531 cases where adequate follow-up results were reported. The PVP ranged from 84% when a diagnosis of strabismus was suggested by the photoscreen reading to 41% for astigmatism. Despite intense attention to follow-up, many children who failed the screening never received a formal eye examination. Conclusions The MTI PhotoScreener can be used by volunteers to screen preschool children and can have a high PVP in organized settings, provided that meticulous attention is paid to photograph interpretation and quality control. The PVP of the MTI PhotoScreener depends on the diagnosis suggested when the photograph is read. Significant obstacles exist in obtaining care for those who fail screening.

Screening for amblyopia in preverbal children with photoscreening photographs : Ii. sensitivity and specificity of the mti photoscreener

Objective To determine the sensitivity and specificity of vision screening using the Medical Technology and Innovations (MTI), Inc., PhotoScreener. Design Cross-sectional study. Participants and testing Three hundred ninety-two children less than 4 years of age received a complete ophthalmologic examination and were photographed using the MTI PhotoScreener. One hundred three children had normal examinations, and the remaining 284 children had conditions of interest for pediatric screening: ptosis, media opacity, refractive error, or strabismus. Five children were excluded. Main outcome measures The grading of the photographs by the manufacturer’s representative was compared with the results of the ophthalmologic examinations. Sensitivity and specificity of vision screening were determined. Results The analysis of all informative photographs resulted in a sensitivity of 65% and a specificity of 87%. The sensitivity of detection for children with some forms of strabismus was high, up to 95% for esotropia of 10Δ or more. Sensitivities for the detection of ptosis, media opacity, and refractive error were poor in patients where strabismus was not also present. Conclusions The MTI PhotoScreener may play a role in preverbal vision screening; identification of two of three children with amblyopiogenic factors before age 4 would be an exciting advance in public health. However, improvement in the ability to identify children with media opacity and refractive error is necessary. Improvements may be possible with modifications of the examination failure and photograph grading criteria.

Screening for amblyogenic factors using a volunteer lay network and the MTI PhotoScreener

Screening for amblyogenic factors using a volunteer lay network and the MTI PhotoScreener

O uso do "photoscreening" no estudo de fatores ambliopigênicos na população infantil

Objetivo: Estudar a precisão do aparelho "MTI Photoscreener" na triagem de uma população infantil, identificando fatores ambliopigênicos como ametropias, anisometropias, estrabismos e cataratas congênitas e opacidades dos meios transparentes. Métodos: Durante o projeto "Veja Bem Brasil" os autores examinaram com uma máquina de "photoscreening" (MTI Photoscreener), 107 crianças, com idade variando entre 6 e 15 anos, comparando estes resultados com aqueles encontrados em posterior exame oftalmológico completo. Resultados: Ao final encontraram 31 (28,97%) crianças com alguma patologia oftalmológica e 76 (71,02%) dentro da normalidade. As análises estatísticas da precisão do aparelho revelaram os seguintes valores: sensibilidade 90,32%; especificidade, 96,05%; valores preditivos positivos e negativos de 90,32% e 96,05%, respectivamente. Conclusão: Os resultados acima citados demonstraram a confiabilidade do teste de "Photoscreening" na triagem de pacientes em idade escolar.

Astigmatism and Amblyopia among Native American Children (AANAC): design and methods

The overall goal of the AANAC study is to improve detection of astigmatism and prevention of amblyopia in populations with a high prevalence of astigmatism. To meet this goal, the study will evaluate four methods of screening for astigmatism in preschool children and will assess both the short-term and long-term benefits of early correction of astigmatism in improving acuity and preventing amblyopia. This paper presents an overview of the design and methodology of the AANAC study. Subjects are members of the Tohono O'Odham Nation, a Native American tribe with a high prevalence of astigmatism. Preschool-age children who attend Head Start are screened with four tools: the Marco Nidek KM-500 autokeratometer, the MTI photoscreener, the Nikon Retinomax K-Plus autorefractor, and the Lea Symbols acuity chart. Sensitivity and specificity for detection of significant astigmatism, as measured by a technique that uses both cycloplegic retinoscopy and cycloplegic autorefraction, is determined for each of the four screening tools. Presence of amblyopia is evaluated by measurement of best-corrected recognition acuity and acuity for orthogonal gratings. Spectacles are provided to all 3-year-old children with =2.00 diopters (D) of astigmatism and all 4- and 5-year-old children with =1.50 D of astigmatism. Persistence of amblyopia after glasses wearing is evaluated by follow-up measurement of best-corrected recognition acuity and acuity for orthogonal gratings, conducted 2-5 months after glasses are prescribed. Long-term effectiveness of early screening and glasses prescription is evaluated through measurement of recognition acuity in two groups of first-grade children: one group who participated in the Head Start program before the intensive vision screening program was initiated, and a second group who participated in the study's Head Start vision screening program.

Pediatric photoscreening for strabismus and refractive errors in a high-risk population

Objective To determine the accuracy of the MTI Photoscreener in detecting strabismus and refractive errors in children. Participants One hundred children underwent MTI photoscreening followed by complete ophthalmologic examination. Six observers graded the photographs for strabismus, according to the location of the corneal light reflexes, and for refractive error, according to the size and location of the light crescent. Results The sensitivity of the MTI Photoscreener in detecting any amblyogenic factor was 80% to 91%, with a specificity of 20% to 67%. The sensitivity and specificity for particular amblyogenic factors varied widely among observers. The ranges were as follows: strabismus, sensitivity = 23% to 50%, specificity = 76% to 96%; myopia, sensitivity = 89%, specificity = 48% to 76%; hyperopia, sensitivity = 20% to 80%, specificity = 88% to 96%; and astigmatism, sensitivity = 46% to 77%, specificity = 79% to 89%. Conclusions These results suggest caution in relying on photoscreening to detect strabismus and refractive errors in children.