Economic and Environmental Impact of Single-use Plastics at a Large Ophthalmology Outpatient Service.

PRéCIS:: The use of disposable tonometer prisms and gonioscopy lenses at a large ophthalmology outpatient service incurs significant financial and environmental waste that may not be justified given the limited data surrounding arguments for their use. PURPOSE: To quantify the economic and environmental burden of single-use plastics from an ophthalmology outpatient service at a large tertiary hospital and describe the relative value and evidence for the safety of disposable versus nondisposable tonometer prisms and gonioscopy lenses. METHODS: The total number of single-use applanation tonometer prisms and gonioscopy lenses used per year at Boston Medical Center (BMC) was estimated, and the average dollars spent and plastic waste generated in kilograms per year were then determined. These values were compared with the total spending and waste that would be produced if the clinic were to use nondisposable tonometer prisms and gonioscopy lenses exclusively. RESULTS: Single-use tonometer prisms cost an average of $70,282 per year and produce ~100.8 kg of plastic waste per year at BMC. Single-use gonioscopy lenses cost ~$9,040 per year and produce 8.8 kg of plastic waste per year at BMC. An excess of $65,185 and 109.6 kg of plastic waste could be avoided each year by only using nondisposable tonometer prisms and gonioscopy lenses at the BMC ophthalmology outpatient service. CONCLUSIONS: Single-use plastics in ophthalmology outpatient services generate significant environmental waste and financial cost compared with nondisposable instruments. This cost may outweigh the benefits of these instruments given the limited data surrounding arguments for their use.

Rebound tonometry with re-sterilised tips versus Goldmann applanation tonometry in children. / Tonometría de rebote con puntas nuevas y reesterilizadas versus tonometría de aplanación Goldmann en niños.

BACKGROUND: The Goldmann applanation tonometer (TAG) is the gold standard for the measurement of intraocular pressure (IOP). In paediatric patients this measurement is challenging. The rebound tonometer (TRB) is an easy to use instrument. In the National Ophthalmology Unit (UNO) the tips of the TRB are re-sterilised (TRB RE). OBJECTIVE: To evaluate the correlation between TRB with new and re-sterilised tips compared to TAG. MATERIALS AND METHODS: A cross-sectional study was conducted on 25 healthy patients between 8 and 12 years of age, chosen at random, and seen in the UNO outpatients department during 2019. IOPs were measured with TRB using re-sterilized tips and then with a new tip, and finally with TAG. RESULTS: There was a correlation between IOP measured with TAG and IOP measured with TRB (P=.0011). No correlation was found between TAG and TRB RE, or TRB with TRB RE. CONCLUSIONS: The TRB can be used in paediatric patients, taking into account that IOP usually overestimates with respect to TAG.

Monitoring ocular hypertension, how much and how often? A cost-effectiveness perspective.

OBJECTIVE: To assess the efficiency of alternative monitoring services for people with ocular hypertension (OHT), a glaucoma risk factor. DESIGN: Discrete event simulation model comparing five alternative care pathways: treatment at OHT diagnosis with minimal monitoring; biennial monitoring (primary and secondary care) with treatment if baseline predicted 5-year glaucoma risk is ≥6%; monitoring and treatment aligned to National Institute for Health and Care Excellence (NICE) glaucoma guidance (conservative and intensive). SETTING: UK health services perspective. PARTICIPANTS: Simulated cohort of 10 000 adults with OHT (mean intraocular pressure (IOP) 24.9 mm Hg (SD 2.4). MAIN OUTCOME MEASURES: Costs, glaucoma detected, quality-adjusted life years (QALYs). RESULTS: Treating at diagnosis was the least costly and least effective in avoiding glaucoma and progression. Intensive monitoring following NICE guidance was the most costly and effective. However, considering a wider cost-utility perspective, biennial monitoring was less costly and provided more QALYs than NICE pathways, but was unlikely to be cost-effective compared with treating at diagnosis (£86 717 per additional QALY gained). The findings were robust to risk thresholds for initiating monitoring but were sensitive to treatment threshold, National Health Service costs and treatment adherence. CONCLUSIONS: For confirmed OHT, glaucoma monitoring more frequently than every 2 years is unlikely to be efficient. Primary treatment and minimal monitoring (assessing treatment responsiveness (IOP)) could be considered; however, further data to refine glaucoma risk prediction models and value patient preferences for treatment are needed. Consideration to innovative and affordable service redesign focused on treatment responsiveness rather than more glaucoma testing is recommended.

A systematic review and cost-effectiveness analysis of tonometer disinfection methods.

OBJECTIVE: The Goldmann applanation tonometer presents the problem of being one of the most widely used pieces of equipment in the ophthalmic clinic and a known risk factor for the transmission of epidemic keratoconjunctivitis (EKC). The purpose of this review is to assess the effectiveness of 3 methods of disinfection: alcohol swabs, immersion in peroxide, and the use of disposable prisms. An economic evaluation is undertaken to assess the cost-effectiveness of the 3 alternatives. In doing so, we contribute an evidence-based overview of the issue at an opportune time, because several jurisdictions are developing protocols regarding tonometer tip disinfection. DESIGN: Systematic review and cost-effectiveness analysis. METHODS: A comprehensive literature review was undertaken with a librarian, comprising searches of 6 electronic databases and hand searches of the grey literature. A 3-level screening process was undertaken by 2 reviewers according to prespecified inclusion and exclusion criteria. Values from included papers were used to inform a cost-effectiveness analysis undertaken using a decision tree model implemented in TreeAge. The analysis was undertaken from the hospital perspective and included all equipment and labour costs. RESULTS: Synthesis of in vitro data indicates that all 3 methods are plausible methods of disinfection with a 64% reduction in log growth of EKC when peroxide is used compared with alcohol swabs. The incremental cost-effective ratios from the cost-effectiveness analysis were $12,000/case averted using peroxide and $61,000/case averted with Tonosafe as compared with alcohol. CONCLUSIONS: Assuming clinical infection rates match in vitro disinfection data, the cost of bleach is high and the cost of Tonosafe is unacceptably high to reduce 1 potential case of adenoviral keratoconjunctivitis.

Reliability of tonosafe disposable tonometer prisms: clinical implications from the Veterans Affairs Boston Healthcare System Quality Assurance Study.

PURPOSE: Given the Veterans Affairs Boston Healthcare System's recent introduction of single-use Tonosafe disposable tonometer prisms as an alternative to Goldmann applanation tonometers (GATs), this study had two aims: to conduct a large-scale quality assurance trial to assess the reliability of intraocular pressure (IOP) measurements of the Tonosafe disposable tonometer compared with GAT, particularly at extremes of pressure; to evaluate the suitability of Tonosafe disposable tonometer prisms as an acceptable substitute for GATs and for clinic-wide implementation in an academic tertiary referral setting. METHODS: Ophthalmology resident physicians measured the IOPs of patients in general and specialty eye clinics with the Tonosafe disposable tonometer and GAT. Tonosafe test-retest reliability data were also collected. A retrospective review of patient charts and data analysis were performed to determine the reliability of measurements. RESULTS: The IOPs of 652 eyes (326 patients) were measured with both GAT and Tonosafe, with a range of 3-34 mm Hg. Linear regression analysis showed R=0.93, slope=0.91, both of which supported the proposed hypothesis, and the y-intercept=-1.05 was significantly different from the hypothesized value. The Tonosafe test-retest repeatability (40 eyes of 40 patients), r=0.977, was very high, which was further supported by linear regression slope=0.993, y-intercept=0.118, and a Tonosafe repeatability coefficient of 2.06, similar to GAT repeatability. CONCLUSIONS: The IOP measurements by Tonosafe disposable prisms correlated closely with Goldmann measurements, with similar repeated measurement variability to GAT. This suggests that the Tonosafe is an acceptable substitute for GAT to measure IOP in ophthalmology clinic settings.

Screening for open angle glaucoma: systematic review of cost-effectiveness studies.

PURPOSE: To systematically review current evidence on the cost-effectiveness of screening strategies for open angle glaucoma (OAG). MATERIALS AND METHODS: Studies that reported both costs and outcomes of alternative screening strategies for OAG were identified by a highly sensitive search of electronic databases (eg, MEDLINE, EMBASE, NHS EED, HTA Database), last search December 2005. Data on costs regarding cases and years of visual impairment prevented, cases of blindness prevented, and cases of OAG detected were extracted. Incremental cost-effectiveness ratios were calculated using data provided in the included studies. RESULTS: Four studies met the inclusion criteria. The latest of these was published in 1997. The screening tests and treatments reported in these studies are now not considered to be best practice. Furthermore, data were not reported in sufficient detail to reinterpret the results of the studies in terms of a common outcome measure. Finally, these studies suffered from methodologic weaknesses that further limit their usefulness for decision making. CONCLUSIONS: Currently, there is insufficient economic evidence on which to base recommendations regarding screening for OAG. New technologies, potentially suitable as screening devices, and new treatments are available. Further research, both in terms of economic models and conduct of clinical trials with concurrent economic evaluation, may help inform policy makers regarding cost-effectiveness and acceptability of screening for OAG.

Cost-effectiveness of early detection and treatment of ocular hypertension and primary open-angle glaucoma by the ophthalmologist.

PURPOSE: To determine the most cost-effective case-finding strategy for the ophthalmologist to detect and treat ocular hypertension (OH) and primary open-angle glaucoma (POAG) at an early stage to prevent blindness. DESIGN: A Markov cost-effectiveness simulation model. METHODS: Three case-finding strategies are analysed and compared. The simulated cohort consists of all initial patients of at least 40 years old visiting an ophthalmic practice. All patients undergo ophthalmoscopy, but tonometry is routinely performed to: (1) all initial patients, (2) high-risk patients only, or (3) no one. The population characteristics are based on data of 1000 initial patients. Transition probabilities are taken from the literature. The (direct) costs of diagnosis and treatment represent those for the Netherlands. The time-horizon of the model is 20 years. An annual discount rate of 4% is used. MAIN OUTCOME MEASURES: Costs, proportion of patients becoming blind, years of blindness. RESULTS: The costliest strategy (1) leads to least blindness. The incremental cost-effectiveness ratio, which shows extra costs per year of vision saved in comparison to the cheapest strategy (3), is lower for strategy (1) than for strategy (2). It amounts to euro1707, not including extra costs due to blindness (eg associated with the use of disability facilities). When such costs exceed euro1707 per patient per year, which is most likely, then strategy (1) becomes cost saving. CONCLUSION: It is most cost-effective to routinely perform tonometry to all initial ophthalmic patients to prevent blindness due to glaucoma.

Use of disposable prism tonometry in routine clinical practice.

AIM: To establish the reliability, efficacy, and safety of disposable prism tonometry and validate its routine use for screening as well as monitoring of glaucoma. METHODOLOGY: Intraocular pressure (IOP) of 400 eyes of 200 consecutive patients who attended the general ophthalmic clinic was checked with both the Goldmann applanation tonometer and a disposable tonometer prism by an experienced examiner after obtaining informed consent. The data were statistically analysed. RESULTS: The mean difference in the IOP between the two types of prisms was 0.1 mmHg (SD+/-1 mmHg). CONCLUSION: Disposable prism tonometry provides a reliable, effective, and safe alternative to Goldmann reusable prism tonometry for routine screening as well as monitoring of glaucoma with the advantages of eliminating the need for chemical disinfection and therefore eliminating the risk of crossinfection.

The cost-effectiveness of various modes of screening for primary open angle glaucoma.

Various modes of screening for glaucoma were defined in terms of different combinations of the three main tests (ophthalmoscopy (O), tonometry (T), and perimetry (P)), together with associated referral criteria. The number of referrals and true positives generated by each mode was estimated for a model population, which was distributed with respect to age, intraocular pressure (IOP), optic disc condition, visual field defects, family history of glaucoma, and myopic status, as indicated by epidemiological studies. The costs of primary examination, and also of the secondary examination of referrals, were estimated for each mode, thus enabling the total cost per true positive to be calculated (in Pound sterling at 1995 UK prices, subsequently converted to US dollars at Pound 1.00 = $1.55.) The modes using O and T routinely, with P either routinely or selectively on all glaucoma high-risk groups, were found to provide the best balance between sensitivity (> or = 80%) and cost per true positive. The latter was around $850 when the cost of ophthalmoscopy could be shared as part of a general eye examination. The calculations assumed a 0.6% prevalence of previously undetected glaucomas in the community: with higher prevalences, costs per true positive would be lower. Screening the 40-59 years age group was found to be about as economic as for older people, when life expectancy was taken into account. It was concluded that glaucoma screening of people over age 40 years could be justifiable, provided that it is worth more than about $850 to detect a new case. Whilst based on UK values, the analysis could be applied to different primary health care settings in other countries.

Cost effectiveness of screening for primary open angle glaucoma.

OBJECTIVES AND SETTING: To determine the cost effectiveness of screening for glaucoma. METHODS: Information on treatment efficacy, diagnostic methods, epidemiological characteristics of glaucoma, and costs were determined from the literature, from administrative databases, and from experts. Scenarios with different screening frequency, age, participation in screening, compliance with treatment, treatment efficacy, and diagnostic tests were examined. RESULTS: The initial scenario comprised three-yearly screening of subjects aged 40-79 by funduscopy and tonometry, followed by perimetry when abnormalities were discovered. The assumption of levels of participation in screening and of compliance with treatment of 75%, and treatment efficacy of 50% resulted in a cost of $C100,000 per year of blindness prevented. A scenario in which screening was restricted to subjects aged 65-79, with the same input variables, would prevent 81% of the cases of blindness prevented with scenario 1, at a cost of $C42,000 per year of blindness prevented. Screening with tonometry only as the initial diagnostic test in subjects aged 65-79 would result in a cost of $C36,000 per year of blindness prevented, but would only prevent 59% of the cases prevented with scenario 1. CONCLUSIONS: There is as yet no proof that treatment of glaucoma or of high intraocular pressure will arrest the progression of glaucoma to blindness. Even when treatment efficacy is assumed to be as high as 50%, however, the cost effectiveness of most glaucoma screening programmes considered would not be competitive.

The value of screening for glaucoma with tonometry.

This paper estimates the value of performing Schiotz tonometry to detect glaucoma in an asymptomatic patient. About 9% of adults over 40 will be found on a single Schiotz tonometry test to have elevated intraocular pressure (IOP). On work-up, about 1 out of 50 of these individuals with high IOP will be found to have glaucoma. Tonometry, however, will miss about half of all patients with glaucoma because they do not have elevated IOPs at the time of the test. Pilocarpine or epinephrine are the most commonly used drugs to treat the disease, but they are not always effective in lowering a patient's IOP or in stopping the progression of field defects. From the available evidence it does not appear that earlier diagnosis makes a substantial difference in the patient's outcome. If all individuals over 40 years of age in a city of 1,000,000 were screened, the total cost of finding and treating about 484 people with chronic simple glaucoma would be on the order of $4,944,866 or about $13,000 per patient potentially benefited. Screening with tonometry does not appear to be warranted.

Glaucoma screening. A cost-effectiveness analysis.

We designed an intricate model of the process of glaucoma screening, diagnosis, and treatment in order to evaluate the medical care costs of such efforts in relation to the benefits in terms of quality-adjusted years of vision saved, utilizing the economic principles of cost-effectiveness analysis. Although a relatively limited data base and numerous assumptions concerning the accuracy of diagnostic tests, the natural history of ocular hypertension and glaucoma, and the effectiveness of available treatment modalities, limit our ability to draw definitive conclusions concerning the cost-effectiveness of various glaucoma screening options, our analysis indicates that glaucoma screening is probably cost-effective when targeted at certain subgroups of the population. Our analysis suggests that changes in several aspects of existing screening policies may be appropriate if cost-effectiveness is to be used as one of the criteria for the efficient allocation of resources to and within screening programs. Specifically, combinations of screening tests and screening targeted at high risk populations such as blacks, diabetics, and relatives of glaucoma patients are probably more cost-effective than screening of the general population with a single test. In younger populations, the importance of detecting ocular hypertension argues for the use of tonometry. Ophthalmoscopy may be more cost-effective in older age groups in whom the higher prevalence of glaucoma outweighs the need for identifying ocular hypertensives. In the very elderly, automated perimetry becomes cost-effective since the detection of established field loss will have greater yield. In addition, it is evident that diversion of resources away from actual screening efforts and towards efforts aimed at improving follow-up and compliance would be an additional cost-effective strategy.

Cost and quality implications of changes in tonometry use by optometrists.

Tonometry, as a test for glaucoma, traditionally was performed routinely only on patients over age 40. In 1974 in the Helling v. Carey case the Supreme Court of Washington (state) held that an ophthalmologist was negligent in failing to administer a glaucoma test to a patient under age 40, and thus failing to diagnose primary open angle glaucoma. In a study performed at the Pennsylvania College of Optometry and the Optometric Center of Maryland an increase of utilization of tonometry on patients under the age of 40 was measured. Available literature indicates that this change occurred nationwide for optometrists in private practice. This change may result in an additional cost for eye care, without a strong indication of an improvement in quality of care.

Blindness prevention through control of ocular hypertension: an epidemiological assessment.

From a case-control study we have quantified the effect (relative risk) of presenting intraocular pressure on visual field loss in primary open angle glaucoma. We found this effect to be modified by both age and sex. Using these effect values we have estimated the potential for prevention of glaucomatous blindness in clinical and community settings. The clinical, public health, and research implications of these findings and estimates are discussed.