Utility analysis of disability caused by amblyopia and/or strabismus in a population-based, historic cohort

The cost-effectiveness of different visual acuity screening strategies in three European countries: A microsimulation study

Childhood vision screening programmes in Europe differ by age, frequency and location at which the child is screened, and by the professional who performs the test. The aim of this study is to compare the cost-effectiveness for three countries with different health care structures.

We developed a microsimulation model of amblyopia. The natural history parameters were calibrated to a Dutch observational study. Sensitivity, specificity, attendance, lost to follow-up and costs in the three countries were based on the EUSCREEN Survey. Quality adjusted life-years (QALYs) were calculated using assumed utility loss for unilateral persistent amblyopia (1%) and bilateral visual impairment (8%). We calculated the cost-effectiveness of screening (with 3.5% annual discount) by visual acuity measurement at age 5 years or 4 and 5 years in the Netherlands by nurses in child healthcare centres, in England and Wales by orthoptists in schools and in Romania by urban kindergarten nurses. We compared screening at various ages and with various frequencies.

Assuming an amblyopia prevalence of 36 per 1,000 children, the model predicted that 7.2 cases of persistent amblyopia were prevented in the Netherlands, 6.6 in England and Wales and 4.5 in Romania. The cost-effectiveness was €24,159, €19,981 and €23,589, per QALY gained respectively, compared with no screening. Costs/QALY was influenced most by assumed utility loss of unilateral persistent amblyopia. For all three countries, screening at age 5, or age 4 and 5 years were optimal.

Despite differences in health care structure, vision screening by visual acuity measurement seemed cost-effective in all three countries.

Quality of life during occlusion therapy for amblyopia from the perspective of the children and from that of their parents, as proxy

BACKGROUND

Parents pity their amblyopic child when they think that they suffer from occlusion therapy. We measured health-related quality of life during occlusion therapy.

METHODS

We developed the Amblyopia Parents and Children Occlusion Questionnaire (APCOQ). It was designed by a focus group of patients, orthoptists and ophthalmologists and consisted of twelve items concerning skin contact of patch, activities, contact with other children, emotions and awareness of necessity to patch. Parents filled out the Proxy Version shortly before the Child Version was obtained from their child. Child Version item scores were compared with Proxy Version item scores and related to the child's age, visual acuity, refraction, angle of strabismus, and cause of amblyopia.

RESULTS

63 children were recruited by orthoptists, and their parents agreed to participate. Three children were excluded: one child with Down-syndrome, one child with cerebral palsy, and one child who had been treated by occlusion therapy. Included were 60 children (mean age 4.57 ± 1.34 SD) and 56 parents. Children had occluded 128 ± 45 SD days at interview. Prior to occlusion, 54 children had worn glasses. Cronbach's α was 0.74 for the Child Version and 0.76 for the Proxy Version. Children judged their quality of life better than their parents did, especially pertaining to skin contact and activities like games and watching TV. Notably, 13 children with initial visual acuity ≥ 0.6 logMAR in the amblyopic eye experienced little trouble with games during occlusion. Quality of life in eight children with strabismus of five years and older correlated negatively (Spearman rank mean rho = -0.43) with angle of strabismus. Children with amblyopia due to both refractive error and strabismus (n = 14) had, relatively, lowest quality of life, also according to their parents, as proxy. Several children did not know why they wore a patch, contrary to what their parents thought.

CONCLUSIONS

Children's quality of life during occlusion therapy is affected less than their parents think, especially regarding skin contact, playing games and watching TV during occlusion. Quality of life correlates negatively with the angle of strabismus in children five years and older. Children do not know why they wear a patch, contrary to what their parents think. Notably, children with low visual acuity in the amblyopic eye, had little difficulty playing games.

Costs and effects of conventional vision screening and photoscreening in the Dutch preventive child health care system

Background

Little is known about costs and effects of vision screening strategies to detect amblyopia. Aim of this study was to compare costs and effects of conventional (optotype) vision screening, photoscreening or a combination in children aged 3–6 years.

Methods

Population-based, cross-sectional study in preventive child health care in The Hague. Children aged 3 years (3y), 3 years and 9 months (3y9m) or 5–6 years (5/6y) received the conventional chart vision screening and a test with a photoscreener (Plusoptix S12C). Costs were based on test duration and additional costs for devices and diagnostic work-up.

Results

Two thousand, one hundred and forty-four children were included. The estimated costs per child screened were €17.44, €20.37 and €6.90 for conventional vision screening at 3y, 3y9m and 5/6y, respectively. For photoscreening, these estimates were €6.61, €7.52 and €9.40 and for photoscreening followed by vision screening if the result was unclear (combination) €9.32 (3y) and €9.33 (3y9m). The number of children detected with amblyopia by age were 9, 14 and 5 (conventional screening), 6, 13 and 3 (photoscreening) and 10 (3y) and 15 (3y9m) (combination), respectively. The estimated costs per child diagnosed with amblyopia were €1500, €1050 and €860 for conventional vision screening, €860, €420 and €1940 for photoscreening and €730 (3y) and €450 (3y9m) for the combination.

Conclusions

Combining photoscreening with vision screening seems promising to detect amblyopia in children aged 3y/3y9m, whereas conventional screening seems preferable at 5/6y. As the number of study children with amblyopia is small, further research on the effects of these screening alternatives in detecting children with amblyopia is recommended.

Microvascular Decompression Versus Stereotactic Radiosurgery for Trigeminal Neuralgia: A Decision Analysis

INTRODUCTION

 Both microvascular decompression (MVD) and stereotactic radiosurgery (SRS) have been demonstrated to be effective in treating medically refractory trigeminal neuralgia. However, there is controversy over which one offers more durable pain relief and the patient selection for each treatment. We used a decision analysis model to calculate the health-related quality of life (QOL) for each treatment.

METHODS

 We searched PubMed and the Cochrane Database of Systematic Reviews for relevant articles on MVD or SRS for trigeminal neuralgia published between 2000 and 2015. Using data from these studies, we modeled pain relief and complication outcomes and assigned QOL values. A sensitivity analysis using a Monte Carlo simulation determined which procedure led to the greatest QOL.

RESULTS

MVD produced a significantly higher QOL than SRS at a seven-year follow-up. Additionally, MVD patients had a significantly higher rate of complete pain relief and a significantly lower rate of complications and recurrence.

CONCLUSIONS

With a decision-analytic model, we calculated that MVD provides more favorable outcomes than SRS for the treatment of trigeminal neuralgia.

Patient-reported utilities in bilateral visual impairment from amblyopia and age-related macular degeneration

BACKGROUND

Utility of visual impairment caused by amblyopia is important for the cost-effectiveness of screening for amblyopia (lazy eye, prevalence 3-3.5 %). We previously measured decrease of utility in 35-year-old persons with unilateral persistent amblyopia. The current observational case-control study aimed to measure loss of utility in patients with amblyopia with recent decrease of vision in their better eye. As these patients are rare, the sample was supplemented by patients with bilateral age-related macular degeneration with similar decrease of vision.

METHODS

From our out-patient department, two groups of patients with recent deterioration to bilateral visual acuity less than Snellen 0.5 (bilateral visual impairment, BVI) were recruited, with either persistent amblyopia and age-related macular degeneration (AMB + AMD), or with bilateral age-related macular degeneration (BAMD). To measure utility, the time trade-off method and the standard gamble method were applied through interviews. Correlations were sought between utility values and visual acuity, age and Visual Function Questionnaire-25 scores.

RESULTS

Seventeen AMB + AMD patients (mean age 72.9 years), and 63 BAMD patients (mean age 79.6 years) were included in the study. Among AMB + AMD, 80 % were willing to trade lifetime in exchange for cure. The overall mean time trade-off utility was 0.925. Among BAMD, 75 % were willing to trade, utility was 0.917. Among AMB + AMD, 38 % accepted risk of death in exchange for cure, overall mean standard gamble utility was 0.999. Among BAMD, 49 % accepted risk of death, utility was 0.998. Utility was not related to visual acuity but it was to age (p = 0.02).

CONCLUSION

Elderly patients with BVI, caused by persistent amblyopia and age-related macular degeneration (AMD) or by bilateral AMD, had an approximately 8 % loss of TTO utility. Notably, the 8 % loss in elderly with BVI differs little from the 3.7 % loss we found previously in 35-year-old persons with unilateral amblyopia with good vision in the other eye. The moderate impact of BVI in senescence could be explained by adaptation, comorbidity, avoidance of risk and a changed percept of cure.

Whole-population vision screening in children aged 4-5 years to detect amblyopia

Amblyopia is a neurodevelopmental disorder that affects at least 2% of most populations and can lead to permanently reduced vision if not detected and treated within a specific period in childhood. Whole-population screening of children younger than 5 years is applied in many countries. The substantial diversity in existing programmes reflects their heterogeneous implementation in the absence of the complete evidence base that is now a pre-requisite for instituting screening. The functional importance of amblyopia at an individual level is unclear as data are scarce, but in view of the high prevalence the population-level effect might be notable. Screening of all children aged 4-5 years (eg, at school entry) confers most benefit and addresses inequity in access to timely treatment. Screening at younger ages is associated with increased risk of false-positive results, and at older ages with poor outcomes for children with moderate to severe amblyopia. We suggest that the real-life adverse effects of amblyopia should be characterised and screening and diagnosis should be standardised.

Performance of the Spot vision screener for the detection of amblyopia risk factors in children

PURPOSE

To compare the accuracy of the Spot photoscreener (Pediavision Holdings LLC Lake Mary, FL) in detecting amblyopia risk factors in children to the 2003 and 2013 referral criteria of the American Association for Pediatric Ophthalmology and Strabismus (AAPOS).

METHODS

The medical records of children 1-6 years of age who underwent vision screening at a single clinic from February 2012 through May 2012 were retrospectively reviewed. Participants were screened with the Spot photoscreener on the same day as a pediatric ophthalmology examination. Visual acuity examination, ocular alignment testing, and cycloplegic refraction were performed that day or within the preceding 6 months for all included subjects by one pediatric ophthalmologist. Sensitivity and specificity of the Spot photoscreening results were compared to the 2003 and to the recently revised 2013 AAPOS referral criteria.

RESULTS

A total of 151 children were included. The Spot had a sensitivity of 80% and specificity of 74%. With the revised 2013 AAPOS referral criteria, the sensitivity was 87% and specificity was 74%.

CONCLUSIONS

The Spot is a fully portable, automated tool for the detection of amblyopia risk factors in children. In this study cohort it was found to reliably detect amblyopia risk in children when compared to the 2003 and 2013 AAPOS referral criteria.

Pediatric intracranial arachnoid cysts: comparative effectiveness of surgical treatment options

PURPOSE

A variety of surgical approaches for the treatment of pediatric intracranial arachnoid cysts exist. In an effort to identify the optimal surgical treatment for this disorder, we developed a decision analytic model to evaluate outcomes of four surgical approaches in children. These included open craniotomy for cyst excision, open craniotomy for cyst fenestration, endoscopic cyst fenestration, and cystoperitoneal shunting.

METHODS

Pooled data were used to create evidence tables, from which we calculated incidence, relative risks, and summary outcomes in quality-adjusted life years (QALYs) for the four surgical treatments. Our study incorporated data up to 5 years postsurgery.

RESULTS

We analyzed 1,324 cases from 36 case series. There were no significant differences in outcome among the four surgical strategies. The QALYs (maximum of 5) for surgical approaches resulted in a range from 4.79 (for open craniotomy and excision) to 4.92 (for endoscopic fenestration).

CONCLUSIONS

Overall quality of life is comparable between patients undergoing open craniotomy for cyst excision or fenestration, endoscopic fenestration, and cystoperitoneal shunting up to 5 years after surgery. While each approach offers unique advantages and disadvantages, an individualized treatment strategy should be employed in the setting of surgical outcome equipoise.

Development and validation of the 21-item children's vision for living scale (CVLS) by Rasch analysis

BACKGROUND

The aim was to develop and validate an instrument called the 'Children's Vision for Living Scale' (CVLS) for the assessment of vision-related quality of life in Saudi Arabian children with and without amblyopia.

METHODS

A 43-item child self-report questionnaire was initially developed based on interviews with children with amblyopia, their parents and eye-care professionals, and a literature review. Following a process that involved the removal of redundant items, 28 items remained and were piloted on children aged five to 12 years with and without amblyopia (n = 48 amblyopic, n = 53 non-amblyopic) living in Saudi Arabia. Rasch analysis was applied to determine whether the 28-item questionnaire fitted the Rasch model. Rasch analysis was used to assess the validity and reliability of the questionnaire. Principal components analysis (PCA) was used to check dimensionality. A 21-item questionnaire resulting from this process was administered in children with (n = 81) and without (n = 82) amblyopia in Saudi Arabia for further validation.

RESULTS

The final 21-item questionnaire had good validity and reliability as demonstrated by person separation of 2.02, person reliability of 0.80 (mean square and standard deviation: infit = 1.01 ± 0.39; outfit = 1.01 ± 0.40) and item reliability of 0.93 (item infit range = 1.33 to 0.78; item outfit range = 0.78 to 1.30). The mean difference between person and item scores of 0.33 ± 0.53 logits (scale range, 2 to -2) indicates that the items are well targeted to the populations. The PCA (dimensionality measures) shows the percentage of variance explained by measures equal to 26.4 per cent (modelled 26.9 per cent) and an eigenvalue of the first contrast of 2.5, which demonstrated good stability.

CONCLUSION

The 21-item CVLS is a valid uni-dimensional child self-report instrument for the assessment of the impact of amblyopia on vision-related quality of life in children with and without amblyopia living in Saudi Arabia.

Posterior chamber toric phakic IOL implantation for the management of pediatric anisometropic amblyopia

PURPOSE

To report the outcomes of toric posterior chamber phakic intraocular lens (PIOL) implantation in children for the treatment of amblyopia due to anisometropia with astigmatism.

METHODS

Six eyes of 6 amblyopic patients aged 5 to 15 years underwent toric PIOL (Visian Toric ICL; STAAR Surgical Company, Monrovia, CA) implantation for refractory anisometropic amblyopia. Preoperative and postoperative clinical evaluation included slit-lamp microscopy, visual acuity, anterior/posterior segment examination, and cycloplegic refraction.

RESULTS

After a mean follow-up of 23 months (range: 15 to 34 months), mean spherical equivalent cycloplegic refraction improved from -10.21 ± 4.62 diopters (D) (range -7.5 to -19.5 D) preoperatively to -0.42 ± 0.39 D (range: -0.625 to +0.125 D) postoperatively. Corrected distance visual acuity ranged from 20/40 to 20/200 preoperatively and 20/20 to 20/60 postoperatively. Five of the 6 eyes gained more than 3 lines of corrected distance visual acuity with a maximum gain of 8 lines in one eye. One eye showed an improvement of more than 2 lines (change in preoperative visual acuity of 20/100 to 20/60 postoperatively). No patients lost any lines of visual acuity. All eyes remained quiet. All PIOLs remained well centered throughout the follow-up period.

CONCLUSION

Toric PIOL implantation may be a viable therapeutic modality in children with clinically significant anisometropic ametropia and astigmatism with secondary amblyopia who have been refractory to medical treatment including spectacles or contact lenses. Longer follow-up visits with larger sample populations will evaluate more effectively the long-term efficacy and late-onset of complications.

The Bruckner test variant (BTV): a promising instrument in detecting vision disorders

BACKGROUND AND PURPOSE

In the Netherlands, children are screened for amblyopia based on the early detection of visual disorders (VOV) protocol by child health care physicians. The positive predictive value (PPV) of the Brückner test variant (BTV) as an alternative method was assessed.

PATIENTS AND METHODS

In this historical prospective analysis, the results of the VOV and BTV methods were compared. Results at the ages of 15 and 27 months of 414 children were compared against diagnosis by the ophthalmologist; follow-up was at 72 months.

RESULTS

Visual disorders were found in 12 of 15 children (14 had an abnormal BTV) who underwent ophthalmological examination. The PPV of the BTV was 86%; 12 of the 14 children with an abnormal BTV had a vision disorder in the preverbal phase.

CONCLUSION

The BTV is superior to the VOV method in the early detection of vision disorders and could be a cost-effective public health intervention.