The cost and yield of photoscreening: impact of photoscreening on overall pediatric ophthalmic costs

Cost-effectiveness of screening for amblyopia among kindergarten children in China

Objective

Current cost-effectiveness analyses of amblyopia screening are mainly from western countries. It remains unclear whether it is cost-effective to implement a preschool amblyopia screening programme in China. Our study aimed to evaluate the cost-effectiveness of a hypothetical kindergarten-based amblyopia screening versus non-screening among 3-year-old children.

Methods

We developed a decision tree combined with a Markov model to compare the cost and effectiveness of screening versus non-screening for 3-year-old children from a third-party payment perspective. The primary outcomes were quality-adjusted life years (QALYs) and the incremental cost-effectiveness ratio (ICER). Costs were obtained from expert opinions in different regions of China. Transition probabilities and health utilities were mainly based on published literature and open sources. Sensitivity analyses were performed to assess the impact of parameters' uncertainty on results.

Results

Base-case analysis demonstrated that the ICER of screening versus non-screening was $17,466/QALY, well below the WTP threshold ($38,223/QALY) for China. One-way sensitivity analysis showed that the prevalence of amblyopia, the transition probability per year from untreated amblyopia to healthy, and the discount rate were the top three factors. The likelihood of cost-effectiveness of screening compared with non-screening was 92.56%, according to probabilistic sensitivity analysis. Scenario analysis also indicated that ICER was lower than the WTP threshold even if the time horizon was shortened or the screening was delayed to the age of 4 or 5.

Conclusions

Amblyopia screening could be considered a cost-effective strategy compared to non-screening for 3-year-old children in China. Screening for children at the age of 4 or 5 may even yield better results.

A population-level post-screening treatment cost framework to help inform vision screening choices for children under the age of seven

PURPOSE/BACKGROUND

Visual acuity (VA) screening in children primarily detects low VA and amblyopia between 3 and 6 years of age. Photoscreening is a low-cost, lower-expertise alternative which can be carried out on younger children and looks instead for refractive amblyopia risk factors so that early glasses may prevent or mitigate the conditions. The long-term benefits and costs of providing many children with glasses in an attempt to avoid development of amblyopia for some of them needs clarification. This paper presents a framework for modeling potential post-referral costs of different screening models once referred children reach specialist services.

METHODS

The EUSCREEN Screening Cost-Effectiveness Model was used together with published literature to estimate referral rates and case mix of referrals from different screening modalities (photoscreening and VA screening at 2, 3-4 years and 4-5 years). UK 2019-20 published National Health Service (NHS) costings were used across all scenarios to model the comparative post-referral costs to the point of discharge from specialist services. Potential costs were compared between a) orthoptist, b) state funded ophthalmologist and c) private ophthalmologist care.

RESULTS

Earlier VA screening and photoscreening yield higher numbers of referrals because of lower sensitivity and specificity for disease, and a different case mix, compared to later VA screening. Photoscreening referrals are a mixture of reduced VA caused by amblyopia and refractive error, and children with amblyopia risk factors, most of which are treated with glasses. Costs relate mainly to the secondary care providers and the number of visits per child. Treatment by an ophthalmologist of a referral at 2 years of age can be more than x10 more expensive than an orthoptist service receiving referrals at 5 years, but outcomes can still be good from referrals aged 5.

CONCLUSIONS

All children should be screened for amblyopia and low vision before the age of 6. Very early detection of amblyopia refractive risk factors may prevent or mitigate amblyopia for some affected children, but population-level outcomes from a single high-quality VA screening at 4-5 years can also be very good. Total patient-journey costs incurred by earlier detection and treatment are much higher than if screening is carried out later because younger children need more professional input before discharge, so early screening is less cost-effective in the long term. Population coverage, local healthcare models, local case-mix, public health awareness, training, data monitoring and audit are critical factors to consider when planning, evaluating, or changing any screening programme.

Economic evaluations of vision screening to detect amblyopia and refractive errors in children: a systematic review

OBJECTIVE

To synthesize and appraise economic evaluations of vision screening to detect vision impairment in children.

METHODS

Literature searches were conducted on seven electronic databases, grey literature, and websites of agencies conducting health technology assessments. Studies were included if they (1) were full, comparative economic evaluations that used cost-utility, cost-benefit, cost-effectiveness, cost-consequence, or cost-analysis methods; (2) described screening services designed to detect amblyopia, strabismus, or uncorrected refractive errors in children under 6 years of age; and (3) published after 1994. High-quality studies were synthesized descriptively. Currencies were reported in 2019 Canadian dollars. Quality was assessed with the Pediatric Quality Appraisal Questionnaire (PQAQ).

RESULTS

Vision screening services were conducted by paid staff, volunteers, or health care professionals in schools or clinics. Thirteen studies were published from five countries: China (n = 1), United States (n = 4), United Kingdom (n = 1), Canada (n = 1), and Germany (n = 6). Analytical techniques included cost-utility/cost-effectiveness combination (n = 2), cost-effectiveness analysis (n = 7), cost-utility analysis (n = 1), cost-benefit analysis (n = 1), cost-consequence analysis (n = 1), and cost analysis (n = 1). Incremental cost-effectiveness ratios ranged from C$1,056 to C$151,274 per additional case detected/prevented and from C$9,429 to C$30,254,703 per additional QALY gained, depending on the type of screening service and comparator. Six studies were determined to be of high quality.

CONCLUSION

Vision screening to detect amblyopia for young children may be cost-effective compared with no screening if amblyopia reduced quality of life. Studies varied significantly in the type of screening services and comparators used. Methodological limitations were common. Future studies would be aided immensely by prospective studies on the impact of amblyopia on the health-related quality of life of young children and guidelines on the effective conduct of vision screening.

The positive predictive value of photoscreening devices for amblyogenic conditions

PURPOSE

To determine the positive predictive value (PPV) of four photoscreening devices in detecting amblyogenic risk factors (ARFs).

METHODS

This is a retrospective cohort study of 1,200 failed vision screenings (FVS) referred to a pediatric eye care practice from general pediatric practices over a 5-year period. Comprehensive eye examinations and cycloplegic refractions were performed. Examination findings and FVS parameters were collected through chart review after completion of visits. Inclusion criteria were age 1-8 years, eye examination within 3 months of initial FVS, and availability of FVS and visit documentation.

RESULTS

A total of 689 patients met inclusion criteria and were included in final analysis. The PPVs were 64.3% (95% CI, 62.73-65.81) for iScreen (n = 455), 26.8% (95% CI, 26.32-27.25) for Spot (n = 113), 18.9% (95% CI, 17.95-19.92) for Plusoptix (n = 38), and 18.5% (95% CI, 17.86-19.19) for GoCheck Kids (n = 55). For comparison, patients referred for failed Titmus tests were also analyzed. The PPV for Titmus testing was 39.3% (95% CI, 36.65-41.99; n = 28).

CONCLUSIONS

The only screening device with a PPV >50% was the iScreen. PPV is a useful metric, because it enables referring providers to guide patients on a post-screening plan and to choose devices that minimize over-referral. Device PPV in the general pediatric population can be markedly different from device PPV in already existing pediatric eye care populations due to inherently different prevalence of ARFs. The iScreen also detected conditions such as cataracts, anisocoria, eyelid abnormalities, esotropia, exotropia, hypertropia, and amblyogenic astigmatism.

Scope and costs of autorefraction and photoscreening for childhood amblyopia-a systematic narrative review in relation to the EUSCREEN project data

Background

Amblyopia screening can target reduced visual acuity (VA), its refractive risk factors, or both. VA testing is imprecise under 4 years of age, so automated risk-factor photoscreening appears an attractive option. This review considers photoscreening used in community services, focusing on costs, cost-effectiveness and scope of use, compared with EUSCREEN project Country Reports describing how photo- and automated screening is used internationally.

Methods

A systematic narrative review was carried out of all English language photoscreening literature to September 10th 2018, using publicly available search terms. Where costs were considered, a CASP economic evaluation checklist was used to assess data quality.

Results

Of 370 abstracts reviewed, 55 reported large-scale community photoscreening projects. Five addressed cost-effectiveness specifically, without original data. Photoscreening was a stand-alone, single, test event in 71% of projects. In contrast, 25 of 45 EUSCREEN Country Reports showed that if adopted, photoscreening often supplements other tests in established programmes and is rarely used as a stand-alone test. Reported costs varied widely and evidence of cost-effectiveness was sparse in the literature, or in international practice. Only eight (13%) papers compared the diagnostic accuracy or cost-effectiveness of photoscreening and VA testing, and when they did, cost-effectiveness of photoscreening compared unfavourably.

Discussion

Evidence that photoscreening reduces amblyopia or strabismus prevalence or improves overall outcomes is weak, as is evidence of cost-effectiveness, compared to later VA screening. Currently, the most cost-effective option seems to be a later, expert VA screening with the opportunity for a re-test before referral.

Successes and shortfalls of community Plusoptix photoscreening: results from the iSee study in Southwestern Ontario

OBJECTIVE

The purpose of this work is to provide the final results from a community-wide photoscreening program in Southwestern Ontario for children aged 18 to 72 months, and to estimate the prevalence of amblyogenic risk factors in this population.

STUDY DESIGN

Prospective, multisite photoscreening program.

PARTICIPANTS

5959 children aged 18-72 months were recruited and screened in Southwestern Ontario at 210 locations over a period of 3 years and 4 months.

METHODS

Ophthalmic screening examinations were performed with the Plusoptix S12 photoscreener. The threshold for the referral criteria used was the manufacturer's criteria on receiver operating characteristics 4.

RESULTS

The screening was negative in 5386 children (90.4%), positive in 403 (6.8%), and unreadable in 170 (2.9%); 42% of all screened children were ≤36 months old. The estimated amblyogenic risk factor prevalence of anisometropia was 4.0%, astigmatism was 3.1%, hyperopia was 1.1%, myopia was 0.4%, and strabismus was 0.4%. Of the 403 referred children, 99 (24.5%) completed a formal eye examination based on the responses returned to the study site.

CONCLUSIONS

This is the first Canadian study that provides data on amblyogenic risk factors based on a volunteer-led photoscreening program. Photoscreening is an effective screening tool, particularly for pre-school-aged children; however, the lack of mandatory follow-up to ensure that children receive proper treatment based on cycloplegic refraction reduces the efficacy of screening.

Critical Assessment of an Ocular Photoscreener

PURPOSE

To determine the accuracy of the PlusoptiX A12 photoscreener (PlusoptiX, Inc., Atlanta, GA) in detecting amblyopia or ambylogenic risk factors in pediatric patients in Nebraska.

METHODS

Using the PlusoptiX A12 photoscreener, data were collected from pediatric patients seen at a single pediatric ophthalmology practice. Each patient was screened using the device and also received a comprehensive ophthalmic examination. The results of the PlusoptiX A12 photoscreener were compared to the gold standard, comprehensive ophthalmic examination findings. The assessment of amblyopia or amblyogenic risk factors in the patients was based on the updated American Association for Pediatric Ophthalmology and Strabismus (AAPOS) referral criteria guidelines.

RESULTS

Data were collected from 219 consecutive pediatric patients (438 eyes) during the 3-month study period. Among the patients, 87 (40%) children were determined to have amblyopia or ambylogenic risk factors after the comprehensive pediatric ophthalmology examination based on the AAPOS guidelines. The PlusoptiX A12 photoscreener was found to have a sensitivity of 93.02%, specificity of 84.96%, false-positive rate of 9.13%, false-negative rate of 2.74%, positive predictive value of 80.00%, and negative predictive value of 94.96%.

CONCLUSIONS

The PlusoptiX A12 photoscreener is viable and comparable to various commercially available devices in the detection of refractive amblyogenic risk factors based on the Nebraska pediatric patient population. Future studies may show increased sensitivity by combining the use of the PlusoptiX A12 photoscreener with an alternate cover test. [J Pediatr Ophthalmol Strabismus. 2018;55(3):194-199.].

Cost and quality of life of overlooked eye care needs of children

Background

The objective of this research was to conduct a systematic review and cost analysis to summarize, from the Ministry of Health perspective, the costs families might incur because of their child’s prescription for refractive errors and amblyopia correction.

Methods

Databases including MEDLINE, Embase, BIOSIS, CINAHL, HEED, ISI Web of Science, and the Cochrane Library as well as the gray literature were searched. Systematic review was conducted using EPPI-Reviewer 4. Percentage difference in cost of glasses and patches per patient per various diagnoses were computed. The cost of glasses and patches was projected over a 5-year time horizon. Cost-utility analysis was performed.

Results

In total, 302 records were retrieved from multiple databases and an additional 48 records were identified through gray literature search. From these, a total of 14 studies (10,388 subjects) were eligible for quantitative analysis. The cost of glasses increased significantly for congenital cataract patients to US$1,820, esotropia patients to US$840, myopes to US$411, amblyopes (mixed) to US$916, anisometropes to US$521, and patients with strabismus to US$728 over a 5-year period making them unaffordable for low-income families. Incremental cost of glasses of congenital cataract patients with delayed treatment was computed to be US$1,690 per health utility gained. Incremental cost of glasses for high refractive error was US$93 per health utility gained in non-compliant children. For amblyopia patients, incremental cost of glasses per quality-adjusted life years gained was US$3,638.

Conclusion

Cost of corrective lenses is associated with significant financial burden and thus other means of mitigating costs should be considered. Eyesight problems in children are perceived as low-priority health needs. Thus, educational interventions on substantial visual deficits of not wearing glasses should be offered to families and governmental health agencies.

Efficient referral thresholds in autorefraction-based preschool screening

PURPOSE

To determine economically efficient referral criteria for a preschool vision-screening program using autorefraction.

DESIGN

Retrospective economic evaluation of a screening protocol.

METHODS

Preschoolers in 2 cities received preschool-based Retinomax screening with a standard referral protocol and as-needed comprehensive eye examinations in 2012-2013. Positive predictive values and referral criteria that minimized cost per case detected were derived using data from San Francisco. These modeled referral criteria were then retrospectively tested for cost-effectiveness against other common criteria in Oakland with sensitivity analysis. Cases were defined by American Association for Pediatric Ophthalmology and Strabismus (AAPOS) criteria for amblyopia risk factors. The perspective was a third-party payer. Costs were obtained from a regional insurance provider.

RESULTS

In San Francisco, 3974 children were screened, 631 referred, and 412 examined. Forty-eight percent of referrals, 301 children, met more than 1 of the referral criteria. Positive predictive values ranged from 7% for myopia to 56% for astigmatism. In Oakland, 2359 children were screened and 269 were examined. When applying the modeled referral criteria derived from San Francisco to the population of Oakland, the cost per case detected was $258. When compared in Oakland, the original referral criteria and criteria based on Vision in Preschoolers study cost, respectively, $424 and $371 per additional case detected. The modeled referral criteria had a lower cost per case detected across sensitivity analysis.

CONCLUSIONS

More stringent referral criteria may reduce the cost per case detected in vision screening and allow more at-risk children to be detected with the same financial resources.

Plusoptix S08 sensitivity in detecting strabismus as amblyogenic risk factor

PURPOSE

To evaluate the sensitivity of photoscreener Plusoptix S08 in screening strabismus.

METHODS

Eighty-three consecutive patients were examined by a single expert to determine the type and amount of the deviation. Then photoscreening was done for all the patients via Plusoptix S08 photoscreener (Plusoptix GmbH, Nuremberg, Germany) on the same day, using the default software for referring the patients.

RESULTS

The age range was between 6 months and 40 years. The overall sensitivity of the device to detect strabismus is 70%; it was 25% for exophoria, 67% for esotropia, 73% for exotropia, and 89% in patients who had mixed strabismus. Regarding degree of deviation, sensitivity was 46% in deviations less than 30 prism diopters (PD) and rises while the degree of deviation increases.

CONCLUSIONS

Our research shows that Plusoptix should not be used solely in evaluating strabismus because its sensitivity decreases significantly specially in esotropic patients with less than 30 PD deviations.

The accuracy of the plusoptiX A08 photoscreener in detecting risk factors for amblyopia in central Iowa

PURPOSE

To evaluate the accuracy of the plusoptiX A08 photoscreener in detecting risk factors for amblyopia in children aged 0-5 years in central Iowa.

METHODS

The medical records of consecutive patients seen at 1 practice during a 2-month period were retrospectively reviewed. All patients were screened with the plusoptiX A08 photoscreener and received a comprehensive pediatric ophthalmology examination. Photoscreening results, according to our age-based criteria, were compared with the comprehensive examination findings. Patients were considered to have amblyopia or amblyogenic risk factors in the comprehensive examination based on the American Association for Pediatric Ophthalmology and Strabismus referral criteria guidelines.

RESULTS

A total of 290 children were examined during the study period. Of these, 190 (66%) patients were found to have amblyopia or amblyogenic risk factors during the pediatric ophthalmology examination on the basis of American Association for Pediatric Ophthalmology and Strabismus guidelines. The plusoptiX A08 offered an overall testability rate of 98%, sensitivity of 87%, specificity of 88%, positive predictive value of 93%, and negative predictive value of 78%. The sensitivity for detection of strabismus ≤20(Δ) was 52%.

CONCLUSIONS

The plusoptiX showed a high sensitivity for the detection of refractive amblyogenic risk factors and had a high successful testability rate in infants; however, it had low sensitivity for detecting strabismus ≤20(Δ). We postulate that sensitivity for detecting amblyogenic risk factors can be improved by combining the use of this instrument with a cover or stereo test.

The potential cost-effectiveness of amblyopia screening programs

PURPOSE

To estimate the incremental cost-effective-ness of amblyopia screening at preschool and kindergarten, the costs and benefits of three amblyopia screening scenarios were compared to no screening and to each other: (1) acuity/stereopsis (A/S) screening at kindergarten, (2) A/S screening at preschool and kindergarten, and (3) photoscreening at preschool and A/S screening at kindergarten.

METHODS

A probabilistic microsimulation model of amblyopia natural history and response to treatment with screening costs and outcomes estimated from two state programs was programmed. The probability was calculated that no screening and each of the three interventions were most cost-effective per incremental quality-adjusted life year (QALY) gained and case avoided.

RESULTS

Assuming a minimal 0.01 utility loss from monocular vision loss, no screening was most cost-effective with a willingness to pay (WTP) of less than $16,000 per QALY gained. A/S screening at kindergarten alone was most cost-effective at a WTP between $17,000 and $21,000. A/S screening at preschool and kindergarten was most cost-effective at a WTP between $22,000 and $75,000, and photoscreening at preschool and A/S screening at kindergarten was most cost-effective at a WTP greater than $75,000. Cost-effectiveness substantially improved when assuming a greater utility loss. All scenarios were cost-effective when assuming a WTP of $10,500 per case of amblyopia cured.

CONCLUSION

All three screening interventions evaluated are likely to be considered cost-effective relative to many other potential public health programs. The choice of screening option depends on budgetary resources and the value placed on monocular vision loss prevention by funding agencies.

Assessment of a modification of Brückner's test as a screening modality for anisometropia and strabismus

BACKGROUND

Current amblyopia screening methods are not cost effective.

AIM

To evaluate the diagnostic capability of a modified Brückner test (MBT) for amblyopiogenic risk factors.

MATERIALS AND METHODS

We applied the MBT using the streak retinoscope to identify anisometropia and strabismus by noting an inter-ocular difference in movement and glow, from children who failed 6/9 Snellen on community vision screening, followed by comprehensive eye examination. STATISITICS: Data were analyzed by 2 × 2 tables for diagnostic test parameters (95% CI).

RESULTS

From 7998 children vision-screened, 392 failed 6/9 VA and were referred. Since 34 failed to reach the centers, and 15 were excluded due to poor/ no glow, data from 343 was analyzed. The prevalence of anisometropia of 0.5D was 17%, of 1D was 11% and of strabismus 5%. For the MBT the accuracy was ≥ 90% (95%CI 89% to 97%) over the three outcomes. The sensitivity, specificity, NPV and +LR for anisometropia of 0.5D were: 0.57 (0.48, 0.64), 0.97 (0.95, 0.98), 0.92 (0.90, 0.93) and 18 (9.7, 35); for 1D: 0.74(0.60, 0.82), 0.95 (0.94, 0.97), 0.97 (0.95, 0.98) and 16 (9.3, 28); and for strabismus: 0.5 (0.32, 0.66), 0.98 (0.97, 0.98), 0.97 (0.96, 0.98) and 20 (9.1, 42).

CONCLUSION

Our data suggests that the MBT is highly accurate and useful for ruling in anisometropia and strabismus in children who fail 6/9 Snellen. The MBT needs further validation, both by different care givers and on differing populations. It offers an affordable, portable, and clinically useful tool to detect anisometropia and strabismus. We suggest that performing an MBT prior to uniocular retinosocpy should be a routine practice.

Overcoming barriers to pediatric visual acuity screening through education plus provision of materials

PURPOSE

The American Academy of Pediatrics (AAP) recommends that LEA and HOTV optotypes be used for vision screening and that adhesive tape be used to occlude one eye during testing. We have developed an educational program designed to improve the quality and efficiency of vision screening. The purpose of this study was to ascertain the effectiveness of this program.

METHODS

All 672 pediatric doctors and nurses in the state of Alaska were surveyed by mail to assess their screening protocol and the number of patients cared for annually. Respondents received educational material, including an instructional video, eye patches for visual acuity testing, and a critical line HOTV test box. Subjects were resurveyed 3 months later to determine whether the instructional intervention altered their established protocol.

RESULTS

Of the 672 practitioners contacted for the survey, 239 (35.6%) responded, representing 31,000 patients, or 62% of all preschool children in Alaska. Use of recommended optotypes was rare (Lea, 3%, HOTV, 7%) compared with the use of nonrecommended optotypes (including use of the E test by 40% of respondents). The postintervention survey was answered by 107 (16%) practitioners. Of these, 24 (23%) reported that they had begun using an adhesive patch for visual acuity testing, whereas 19 (18%) had begun using AAP-recommended testing optotypes.

CONCLUSIONS

In-office video education and provided adhesive eye patches increased the use of patches in primary care preschool vision screening. Mail delivery was less effective than anticipated.

Computer-based real-time analysis in mobile ocular screening

Mobile ocular telemedicine is potentially an effective method to provide service in medically underserved areas and to screen large populations for abnormalities. Currently, digital images are acquired, stored, and transferred to readers for evaluation, after which the results are provided to the subjects. The transfer of large image files and the timeliness of the subsequent reading of images are significant factors for practical implementation of effective telemedicine screening. This work examines the feasibility of in situ real-time computer analysis of digital images to determine and classify the image results as normal and abnormal. This retrospective study used a photoscreening database of 360 patients ranging in ages from 6 months to 18 years. Computer analysis automatically classified the binocular photorefraction (PR) images, and these PR results were compared to those of the subjective clinical eye examinations provided. With an average processing time of approximately 15 seconds per examinee, the analysis found that the PR results can be categorized as: a positive group that requires referral (186 cases) with a predictive value of 98.9% (2 false-positives); a negative group (144 cases) with a predictive value of 89.6% (15 false-negatives); and an uncertain group (30 cases or 8.3%) that required resolution by readers. The real-time analysis code reduces by approximately 92% the manpower for image grading and electronic transmission at this stage of ocular evaluation. These results indicate the feasibility of this approach.

Calibration of photoscreeners for single-subject, contact-induced hyperopic anisometropia

BACKGROUND

In 1999, the threshold anisometropic hyperopia for photoscreening toddlers and preschoolers was determined to be 1.50 D. We compared crescent size from induced anisometropic hyperopia using three commercially available photoscreeners and compared them with miniature digital video cameras, which have a flash-to-lens dimension similar to two of the three photoscreeners. Photoscreeners were compared with a remote autorefractor.

METHODS

Anisometropia was induced by placing several known minus contact lenses (-1.00, -1.50, and -2.00 D) in the nondominant eye of a visually healthy, orthophoric emmetrope older than 3 years. Photographs were taken in light and dim conditions with all three cameras with and without the contact lenses. Corneal diameter, pupil diameter, and crescent location were determined. A protocol for flash initiation, focus, and distance was determined for the digital cameras.

RESULTS

Under light and dim ambient light, no camera yielded a significant hyperopic crescent for emmetropia (no contact lens) or induced 1.0-D anisometropia. We propose a simple measure, "delta center crescent" distance from the center of the pupil to the edge of the crescent. Delta center crescent less than 1.5 mm identified most examples of threshold hyperopic anisometropia. The ideal distance for photoscreening using the digital cameras is approximately 1.6 m, whereas the commercially available photoscreeners focus at 1.0 m.

CONCLUSIONS

We have developed a protocol for photoscreening and its interpretation with a miniature digital video camera weighing 400 g and costing approximately dollar 1,000. Threshold anisometropic hyperopia can be determined from digital still or audio-labeled video flash images if the pupils are at least 4 mm.