Glaucoma Screening Program Research Articles

Diagnostic Ability and Repeatability of a New Supra-Threshold Glaucoma Screening Program in Standard Automated Perimetry.

PurposeWe assess the diagnostic ability and repeatability of a new suprathreshold glaucoma screening test (GST) comprising 28 test points and a 1-of-3 sampling strategy at 95% of the normal limit for standard automated perimetry (SAP) in early to advanced glaucoma.MethodsThis prospective cross-sectional study included 96 eyes of patients with early, moderate, or advanced glaucoma and 37 eyes of normal controls. Participants were evaluated by the G-Dynamic threshold test once and the GST twice, in random order, using the Octopus 600 perimeter. The diagnostic ability of GST was assessed by comparison with the G-Dynamic threshold obtained by receiver operating characteristic analysis. Repeatability was assessed by κ statistics for agreement on glaucoma diagnosis and each test point.ResultsAlthough the G-Dynamic test exhibited significantly higher areas under the curve (AUC) than the GST1st (P = 0.009) in early glaucoma, there were no significant differences in any other AUCs between the two methods. The κ values for repeatability of glaucoma diagnosis and each test point were 0.747 to 1.0 and 0.537 to 1.0, respectively. The duration of the GST in the control and early glaucoma groups was less than a minute, while that in the moderate and advanced glaucoma groups was within 1.5 minutes.ConclusionThe diagnostic ability of the new suprathreshold GST for early to advanced glaucoma was high, with moderate to strong repeatability and short test duration.Translational RelevanceThere currently are no prominent suprathreshold screening strategies using SAP. The GST would be an effective clinical method for glaucoma screening.

Cost-effectiveness and cost utility of community screening for glaucoma in urban India

ObjectivesPopulation-based screening for glaucoma has been demonstrated to be cost-effective if targeted at high-risk groups such as older adults and those with a family history of glaucoma, and through use of a technician for conducting initial assessment rather than a medical specialist. This study attempts to investigate the cost-effectiveness of a hypothetical community screening and subsequent treatment programme for glaucoma in comparison with current practice (i.e. with no screening programme but with some opportunistic case finding) in the urban areas of India. Study designA hypothetical screening programme for both primary open-angle glaucoma and angle-closure disease was built for a population aged between 40 and 69 years in the urban areas of India. MethodsScreening and treatment costs were obtained from an administrator of a tertiary eye hospital in India. The probabilities for the screening pathway were derived from published literature and expert opinion. The glaucoma prevalence rates for urban areas were adapted from the Chennai Glaucoma Study findings. A decision-analytical model using TreeAge Pro 2015 was built to model events, costs and treatment pathways. One-way sensitivity analyses were conducted. ResultsThe introduction of a community screening programme for glaucoma is likely to be cost-effective, the estimated incremental cost-effectiveness ratio (ICER) values being ▪10,668.68 when compared with no screening programme and would treat an additional 4443 cases and prevent 1790 person-years of blindness over a 10-year period in the urban areas of India. Sensitivity analyses revealed that glaucoma prevalence rates across various age groups, screening uptake rate, follow-up compliance after screening, treatment costs and utility values of health states associated with medical and surgical treatment of glaucoma had an impact on the ICER values of the screening programme. ConclusionsIn comparison with current practice (i.e. without a screening programme but with some opportunistic case finding), the introduction of a community screening programme for glaucoma for the 40–69 years age group is likely to be relatively cost-effective if implemented in the urban areas of India.

Cost and detection rate of glaucoma screening with imaging devices in a primary care center.

PurposeTo analyze the cost and detection rate of a screening program for detecting glaucoma with imaging devices.Materials and methodsIn this cross-sectional study, a glaucoma screening program was applied in a population-based sample randomly selected from a population of 23,527. Screening targeted the population at risk of glaucoma. Examinations included optic disk tomography (Heidelberg retina tomograph [HRT]), nerve fiber analysis, and tonometry. Subjects who met at least 2 of 3 endpoints (HRT outside normal limits, nerve fiber index ≥30, or tonometry ≥21 mmHg) were referred for glaucoma consultation. The currently established (“conventional”) detection method was evaluated by recording data from primary care and ophthalmic consultations in the same population. The direct costs of screening and conventional detection were calculated by adding the unit costs generated during the diagnostic process. The detection rate of new glaucoma cases was assessed.ResultsThe screening program evaluated 414 subjects; 32 cases were referred for glaucoma consultation, 7 had glaucoma, and 10 had probable glaucoma. The current detection method assessed 677 glaucoma suspects in the population, of whom 29 were diagnosed with glaucoma or probable glaucoma. Glaucoma screening and the conventional detection method had detection rates of 4.1% and 3.1%, respectively, and the cost per case detected was 1,410 and 1,435€, respectively. The cost of screening 1 million inhabitants would be 5.1 million euros and would allow the detection of 4,715 new cases.ConclusionThe proposed screening method directed at population at risk allows a detection rate of 4.1% and a cost of 1,410 per case detected.

Causes of visual impairment and blindness in children at Instituto Benjamin Constant Blind School, Rio de Janeiro

Abstract Objective: To determine the main causes of visual impairment and blindness in children enrolled at Instituto Benjamin Constant blind school (IBC) in 2013, to aid in planning for the prevention and management of avoidable causes of blindness. Methods: Study design: cross-sectional observational study. Data was collected from medical records of students attending IBC in 2013. Causes of blindness were classified according to WHO/PBL examination record. Data were analyzed for those children aged less than 16 years using Stata 9 program. Results: Among 355 students attending IBC in 2013, 253 (73%) were included in this study. Of these children, 190 (75%) were blind and 63 (25%) visually impaired. The major anatomical site of visual loss was retina (42%), followed by lesions of the globe (22%), optic nerve lesions (13.8%), central nervous system (8.8%) and cataract/pseudophakia/aphakia (8.8%). The etiology was unknown in 41.9% and neonatal factors accounted for 30,9% of cases. Forty-eight percent of cases were potentially avoidable. Retinopathy of prematurity (ROP) was the main cause of blindness and with microphthalmia, optic nerve atrophy, cataract and glaucoma accounted for more than 50% of cases. Conclusion: Provision and improvement of ROP, cataract and glaucoma screening and treatment and programs could prevent avoidable visual impairment and blindness.

Cambridge community Optometry Glaucoma Scheme

With a higher life expectancy, there is an increased demand for hospital glaucoma services in the United Kingdom. The Cambridge community Optometry Glaucoma Scheme (COGS) was initiated in 2010, where new referrals for suspected glaucoma are evaluated by community optometrists with a special interest in glaucoma, with virtual electronic review and validation by a consultant ophthalmologist with special interest in glaucoma. 1733 patients were evaluated by this scheme between 2010 and 2013. Clinical assessment is performed by the optometrist at a remote site. Goldmann applanation tonometry, pachymetry, monoscopic colour optic disc photographs and automated Humphrey visual field testing are performed. A clinical decision is made as to whether a patient has glaucoma or is a suspect, and referred on or discharged as a false positive referral. The clinical findings, optic disc photographs and visual field test results are transmitted electronically for virtual review by a consultant ophthalmologist. The number of false positive referrals from initial referral into the scheme. Of the patients, 46.6% were discharged at assessment and a further 5.7% were discharged following virtual review. Of the patients initially discharged, 2.8% were recalled following virtual review. Following assessment at the hospital, a further 10.5% were discharged after a single visit. The COGS community-based glaucoma screening programme is a safe and effective way of evaluating glaucoma referrals in the community and reducing false-positive referrals for glaucoma into the hospital system.

Cost-effectiveness in the Treatment of Glaucoma

The cost-effectiveness of treating different types of glaucoma and ‘pre-glaucoma status’—namely ocular hypertension, primary angle closure suspect, and primary angle closure—were investigated by numerous studies. Overtreatment could lead to undesirable opportunity cost and unnecessary exposure to adverse effects for the patients; under-treating moderate to advance glaucoma could lead to preventable blindness. Despite being a leading cause of blindness, the need for a comprehensive glaucoma screening program and early intervention of pre-glaucoma status is questionable. Numerous reports have investigated the cost-effectiveness of treating ocular hypertension, primary open angle glaucoma, and normal tension glaucoma. The cost-effectiveness of different treatment modalities and their application at different stages of glaucoma were also discussed. To date, there is no cost-effectiveness analysis for the treatment of primary angle closure glaucoma. Some early reports also suggested that prophylactic treatment for primary angle closure and primary angle closure suspect might not be the most effective modalities.

Population and High-Risk Group Screening for Glaucoma: The Los Angeles Latino Eye Study

To evaluate the ability of various screening tests, both individually and in combination, to detect glaucoma in the general Latino population and high-risk subgroups. The Los Angeles Latino Eye Study is a population-based study of eye disease in Latinos 40 years of age and older. Participants (n = 6082) underwent Humphrey visual field testing (HVF), frequency doubling technology (FDT) perimetry, measurement of intraocular pressure (IOP) and central corneal thickness (CCT), and independent assessment of optic nerve vertical cup disc (C/D) ratio. Screening parameters were evaluated for three definitions of glaucoma based on optic disc, visual field, and a combination of both. Analyses were also conducted for high-risk subgroups (family history of glaucoma, diabetes mellitus, and age ≥65 years). Sensitivity, specificity, and receiver operating characteristic curves were calculated for those continuous parameters independently associated with glaucoma. Classification and regression tree (CART) analysis was used to develop a multivariate algorithm for glaucoma screening. Preset cutoffs for screening parameters yielded a generally poor balance of sensitivity and specificity (sensitivity/specificity for IOP ≥21 mm Hg and C/D ≥0.8 was 0.24/0.97 and 0.60/0.98, respectively). Assessment of high-risk subgroups did not improve the sensitivity/specificity of individual screening parameters. A CART analysis using multiple screening parameters-C/D, HVF, and IOP-substantially improved the balance of sensitivity and specificity (sensitivity/specificity 0.92/0.92). No single screening parameter is useful for glaucoma screening. However, a combination of vertical C/D ratio, HVF, and IOP provides the best balance of sensitivity/specificity and is likely to provide the highest yield in glaucoma screening programs.

THE ADDITIONAL YIELD OF A PERIODIC SCREENING PROGRAMME FOR OPEN-ANGLE GLAUCOMA: A POPULATION-BASED COMPARISON OF INCIDENT GLAUCOMA CASES DETECTED IN REGULAR OPHTHALMIC CARE WITH CASES DETECTED DURING SCREENING

THE ADDITIONAL YIELD OF A PERIODIC SCREENING PROGRAMME FOR OPEN-ANGLE GLAUCOMA: A POPULATION-BASED COMPARISON OF INCIDENT GLAUCOMA CASES DETECTED IN REGULAR OPHTHALMIC CARE WITH CASES DETECTED DURING SCREENING

Knowledge about glaucoma and barriers to follow-up care in a community glaucoma screening program

Objective: To assess perceived barriers to glaucoma follow-up care, including the lack of glaucoma knowledge and the lack of health care access, among participants in a community glaucoma screening program. Design: Community survey. Participants: Two hundred forty-three consecutive participants in a series of free glaucoma screenings between November 2002 and August 2003. Methods: The survey consisted of 20 questions designed to elicit knowledge of glaucoma and perception of potential barriers to follow-up care. Our aim was to find correlations between patient demographics and knowledge of glaucoma as well as perceived potential barriers to follow-up care. The data were analyzed using SPSS, v. 10.1. Results: The average age of the respondents was 70 years, and females predominated (66%). About half of the respondents knew of an eye doctor in their neighborhood, and 60% had had an eye examination in the past year. Two hundred twenty-two (91%) indicated they could get to an eye doctor if the screening examination indicated they needed a follow-up examination. Two hundred twenty (90.5%) had medical insurance. One hundred seventy-eight (73%) of the participants had heard of glaucoma; 71 (29%) identified an accurate definition of glaucoma. The level of education and the language spoken at home were correlated with both glaucoma awareness ( p < 0.001; p < 0.001) and knowledge of an accurate definition of glaucoma ( p < 0.001; p < 0.025). Conclusions: In this population, a lack of adequate education about glaucoma may be more significantly associated with poor follow-up rates than a lack of access to care in those identified as glaucoma suspects.

Comparing Optic Nerve-head-size Measurements by the Heidelberg Retina Tomograph With Fundus Photography Performed With a Novel Focusing Technique

To compare disc areas as measured with the Heidelberg Retina Tomograph (HRT) to those obtained with a fundus camera. A nonrandomized comparative trial. Forty-six patients (88 eyes) who were participating in a glaucoma-screening study. Disc areas from fundus photographs taken with a Nidek nonmydriatic camera were measured in pixels (Adobe photoshop 7.0). A magnification factor was determined, using a previously described technique that uses the position of the focusing slide on the camera to account for the spherical refractive error. The resulting calculated disc areas were then compared with the disc areas as measured with the HRT. Disc area. The limits of agreement between the 2 techniques were 0.49 and -0.51 mm2, indicating that the range of differences between these imaging techniques was approximately 1 mm2. Using a Bland-Altman plot, the distribution of residuals indicated that the 2 techniques do not differ in a systematic way. Disc area measurements can be reasonably determined from digital fundus photography if corrected for focusing slide position when compared with HRT. This may have useful applications for both clinical glaucoma patient care and population-based glaucoma-screening programs.

The additional yield of a periodic screening programme for open-angle glaucoma: a population-based comparison of incident glaucoma cases detected in regular ophthalmic care with cases detected during screening

Aim:To study the additional yield of a periodic screening programme for open-angle glaucoma (OAG) by comparing, in a population-based setting, incident OAG (iOAG) cases detected in regular ophthalmic care with...

Vergleich der mittleren zentralen Hornhautdicke bei Patienten eines Glaukomvorsorgeprogramms und ambulanten Glaukompatienten

The aim of this study was to compare central corneal thickness (CCT) and intraocular pressure in patients participating in a glaucoma screening programme and patients who were examined in the glaucoma unit. 406 patients of a glaucoma screening programme (Salzburg-Moorfields collaborative glaucoma study) were included in this study. In addition a group of 406 patients who were admitted to the glaucoma clinic for a detailed glaucoma examination was included (outpatient clinic group). In all participants central corneal thickness (CCT) was measured and possible relations of CCT within the study groups were statistically analysed. In the population screening group the mean central corneal thickness in normal subjects was 536+/-4.3 microm, in patients with ocular hypertension (OHT) 552+/-5.7 microm, patients suffering from a normal tension glaucoma (NTG) showed a mean CCT of 534+/-14.2 microm and those with primary open angle glaucoma (POAG) had a value of 521+/-17.9 microm. In the 'outpatient clinic group' the OHT subgroup had a mean CCT of 553+/-6.8 microm, the NTG subgroup of 529+/-26.5 microm and the one with POAG had a mean of 527+/-19.8 microm. In addition, CCT was measured in all glaucoma patients whose "partner" eye was healthy (544+/-5 microm) and included in this study as part of the normal subgroup. In both groups (screening group and outpatient group), CCT was significantly higher in OHT patients than in normals. In contrast, no statistically significant difference between normals and NTG or POAG patients was detected. Intraocular pressure was significantly lower in the screening groups than in the other ones. Our data confirm the previously published results concerning OHT and healthy subjects. In this study no significant difference between NTG or POAG subjects and normal eyes was detected. The lower IOP in the screening population can be explained by the fact that patients contacting the screening program are self selected whereas patients of the glaucoma unit are admitted by practising ophthalmologists and are, therefore, rather advanced cases or carrying special risk factors.

Introducing the shape of globe as a predisposing factor for glaucoma

Glaucoma is a common blinding disease worldwide with a number of risk factors such as intraocular pressure, myopia, gender, race and hyperopia. Here we introduce eyeball's shape as a predisposing factor for glaucoma. If the eyeball is a sphere, the stress distribution is homogenous. We assume the eyeball as a non sphere. Then, the distribution of stress will not be homogenous. Different individuals have different eyeball's shapes and different patterns of stress distribution in their eyes. So based on the eyeball's shape deviation from a sphere they will have different risks for glaucoma. The eyeball is routinely considered as a sphere, but some evidences show that the globe is not a sphere. Two empirical observations are consistent with the hypothesis. The first is that ethnicity and sex are established risk factors for glaucoma. On the other hand there are several morphological differences in the body structure among individuals. According to these anatomical differences, eye's shape is different among different races and between two sexes. Secondly, there are some conditions such as myopia and hyperopia in them the shape of the globe has been changed. These conditions are risk factors for glaucoma too. Glaucoma screening program for early detection of high risk individuals is very important. Current diagnostic procedures of glaucoma do not take the shape of eyeball into account. We suggest using eyeball's shape for early glaucoma detection. There are three other factors in addition to eyeball's shape, including thickness of the globe's wall, intraocular pressure, and inner radius that should be measured together for each individual and stress load should be calculated in different points of the globe. Then eyes with more stress load in site of injury are more prone for glaucoma. More accurate measurements of the factors which are contributing in stress value for each case, lead us toward better glaucoma screening.

Cost effectiveness and cost utility of an organized screening programme for glaucoma

Cost effectiveness and cost utility of an organized screening programme for glaucoma

Cost effectiveness and cost utility of an organized screening programme for glaucoma

To assess the cost effectiveness and cost utility of an organized screening programme for glaucoma. The previous cost-effectiveness studies of screening show inconsistent results, and the cost utility of screening has not been assessed. An organized screening programme was simulated using Markov modelling in a population aged 50-79 years at 5 year intervals. The programme ended when the subjects reached the age of 80 years. The comparator was opportunistic case finding. The main outcome measures were cases and years of severe visual disability avoided, quality-adjusted life years (QALYs) gained and direct healthcare and non-healthcare costs. The incremental cost of 1 year of avoided visual disability by screening was euro32 602. The cost of one QALY gained by screening was euro9023 with a discount rate of 5%. During the average 20 year time horizon considered, the cumulative incremental costs of screening in a population of 1 million people would be euro30 million, producing 3360 incremental QALYs and 930 years of avoided visual disability for 701 persons. The results were sensitive to the estimates of several parameters, especially screening cost and specificity of screening tests (96-99% specificity required). An organized screening programme could be a cost-effective strategy especially in older age groups, in which screening is clearly more likely to be acceptable to decision makers at any level in terms of their willingness to pay for a QALY. Modelling includes some uncertainty especially concerning the specificity of diagnostic tests and screening cost.

Über den Zusammenhang zwischen Lebensalter und Prävalenz sowie Inzidenz des primären Offenwinkelglaukoms in der „Salzburg-Moorfields-Collaborative-Glaucoma”-Studie

It is the aim of this study to describe both the relationship between age and prevalence as well as age and 5-year incidence of primary open angle glaucoma (POAG) for a homogeneous population cohort. The result of the regression model for the prevalence are compared with the models of Tuck-Crick and Quigley-Vitale. In addition, estimations for the number of 5-year incidence cases of POAG are provided for individuals at the age of 40-80 years in Austria for the years in 2001-2006, 2010-2015, 2020-2025 and 2030-2035. The "Salzburg Moorfields Collaborative Glaucoma Study" (SMCGS) is embedded in a government-supported glaucoma blindness prevention programme in Salzburg county, Austria, which is designed for a screening and follow-up period of at least 10 years. Each subject receives a complete ophthalmological examination. In total, the findings of 853 subjects are analysed and evaluated applying the guidelines of the European glaucoma society. The results of the regression analysis for the prevalences are in good agreement with the models of Tuck-Crick and Quigley-Vitale. The best correlation was found for individuals between 40 and 80 years of age. The 5-year incidences increase is statistically significant (p < 0.001) with increasing age: the 5-year incidences of individuals at the age of 40, 50, 60, 70 and 80 years are 0.07 % (95 % confidence interval: 0.005 - 0.9 %), 0.2 % (0.04 - 1.2 %), 0.7 % (0.3 - 1.9 %), 2.3 % (1 - 5.2 %) and 6.9 % (1.7 - 24.0 %), respectively. The age-dependent prevalences in this glaucoma screening program are in good agreement with the regression models of Tuck-Crick and Quigley-Vitale, especially in the age range of 40 - 80 years. The model for the 5-year incidences describes the tight relationship between age and 5-year risk for POAG. We estimate the number of new POAG cases in Austria in 2001-2006, 2010-2015, 2020-2025 and 2030-2035 at the age between 40 and 80 years to reach 49 100, 52 100, 62 000 and 69 600 patients, respectively.

The Projected Increase in Glaucoma Due to the Aging Population in Austria from 2001 to 2031: Results Based on Data of the Salzburg-Moorfields Collaborative Glaucoma Study

The aim of this study is to present the projected increase in definite primary open angle glaucoma (POAG) and related diseases in Austria from 2001 to 2031. The present work is based on two data sources: population projections in Austria and detection rates of the Salzburg-Moorfields Collaborative Glaucoma Study for Austrians in the age groups 40-54 years, 55-69 years, and 70 years and above. The estimates of this glaucoma screening program are based on a total of 3419 subjects. Sensitivity analyses were applied to test the effects of higher and lower sets of prevalence assumptions on the extent of the probable projections. The number of Austrians with definite POAG, early POAG, POAG suspects, and ocular hypertension (OHT) is expected to increase until 2031 by 0.5%, 43.1%, and 65.6% in the three age groups specified above, respectively. The overall number of Austrians with POAG at the age of 40 or older is estimated to increase from 67,600 in 2001 to 96,400 in 2031. This corresponds to an increase of 42% from 2001 to 2031 (lower scenario: 37%, upper scenario: 47%). Similar increases are expected for individuals with early POAG, POAG suspects, and OHT. These projections provide an objective basis to estimate the resources that may be needed by health authorities and care providers such as ophthalmologists in the future and should help to design glaucoma blindness prevention programs or screening studies in Austria. The predicted continuous increase of Europe's older population will prove to become a challenge for public health professionals not only for diagnosis and monitoring, but also for the treatment of glaucoma.

Screening for glaucoma in Canada: a systematic review of the literature

Background: To provide a recommendation on screening for glaucoma in Canada based on a review of recent evidence available in the literature. Methods: A systematic literature review was performed to identify publications from MEDLINE, EMBASE, HealthSTAR, and Cochrane databases from 1990 to 2005. Relevant articles were categorized as economic studies, epidemiologic and intervention studies, or policy papers. Web sites and publications from provincial, state, national, and international health authorities were reviewed for policy recommendations and guidelines. Results: We identified 39 articles (34 epidemiology and intervention, and 5 economic studies) for the review. From the economic studies, 2 were simple cost analyses and 3 were full economic evaluations (cost-effectiveness). Gaps were observed from these economic studies, where incremental cost-effectiveness analyses of modelled screening programmes were not observed. A large number of alternatives (i.e., screening techniques) and diverse outcome measures were found in the 34 epidemiology and intervention studies. This shows that evidence on the effectiveness of glaucoma screening programmes is available to be used in future modelled analyses. Neutral recommendation made by the Canadian Task Force on Periodic Health Examination regarding glaucoma screening in Canada could be related to the lack of reliable data and models used in past cost-effectiveness analyses. Interpretation: A need exists to reevaluate the cost-effectiveness of a screening programme for glaucoma in Canada with updated efficacy and cost data.Health and monetary benefits could be improved compared with current practice and decision-makers would have the best available data when reevaluating the policy on screening for glaucoma.

Resource use and Costs for a Glaucoma Screening Program in Austria: An 8-Year Review.: A Cost-Consequence Analysis Based on the Salzburg-Moorfields Collaborative Glaucoma Study

The aim of this study is to report costs, detection rates, and resources needed for detection of primary open angle glaucoma and related diseases in a glaucoma screening program in Salzburg, Austria, over a period of 8 years. The Salzburg-Moorfields Collaborative Glaucoma Study performed a complete ophthalmologic examination on a total of 4864 subjects within a study period of approximately 8 years (98 months). The total numbers reported are total number of subjects screened at the initial examination and follow-up examinations; total working hours and estimated working hours per visit for one ophthalmologist and two medical assistants; direct costs per visit; detection rates for subjects; and corresponding costs per true positive case diagnosed with definite primary open angle glaucoma (POAG), early POAG, POAG suspect, ocular hypertension (OHT), and glaucoma artefact. Within the screening period of 98 months, a total of 9427 examinations and second verification checks were performed: 5466 at the initial examination, 404 at the 1-year follow-up, 815 at the 2-year follow-up, 339 at the 3-year follow-up, 225 at the 4-year follow-up, 1059 at the 5-year follow-up, 996 at the 6-year follow-up, 118 at the 7-year follow-up, and 5 at the 8-year follow-up. The total amount of time spent for screening was 23,814 working hours. We estimate the costs per visit at EUR 123 for each initial examination, EUR 28 for each second confirmation check, and EUR 95 per follow-up examination. The following detection rates were observed: definite POAG: 1.7% (95% CI: 1.3-2.2%), early POAG: 2.9% (95% CI: 2.3-3.5%), POAG suspect: 8.5% (95% CI: 7.6-9.4%), OHT: 2.2% (95% CI: 1.7-2.7%), glaucoma artefact or other causes: 5.8% (95% CI: 5.1-6.6%), normal cases: 79% (95% CI: 78-80%). Direct costs per visit were considerably higher than those reported in the Netherlands or the United Kingdom. If a health care provider decides to perform a glaucoma screening within this setting, the costs for the detection of a new case are EUR 7250 for definite POAG, EUR 4250 for early POAG, EUR 1450 for POAG suspect, EUR 5600 for OHT, EUR 2100 for glaucoma artefact case, and EUR 156 for a normal case.

Validity of Screening for Glaucomatous Optic Nerve Damage Using Confocal Scanning Laser Ophthalmoscopy (Heidelberg Retina Tomograph II) in High-Risk Populations: A Pilot Study

To evaluate whether confocal scanning laser ophthalmoscopy (Heidelberg Retina Tomograph II [HRT II], Heidelberg Engineering, Heidelberg, Germany) is a valid tool for the detection of glaucomatous optic nerve damage. Observational, cross-sectional, nonconsecutive study in Montreal, Canada. Three hundred three nonconsecutive, high-risk persons were enrolled during a 6-month period. Participants underwent HRT II testing and a standard ophthalmologic examination, including gonioscopy, intraocular pressure measurement, and optic disc grading. Positive likelihood ratio (PLR) and negative likelihood ratio (NLR), sensitivities and specificities, positive predictive value (PPV) and negative predictive value (NPV), and kappa coefficients of agreement of Moorfields regression analysis (MRA), cup shape measure (CSM), height variation contour (HVC), and mean retinal nerve fiber layer thickness (MRNFL). Three hundred three participants were enrolled, and 291 were examined clinically; 21 (7.2%) were found to have glaucoma. Heidelberg Retina Tomograph II testing was performed successfully and was of acceptable quality in 531 of 601 eyes (88%). When MRA was compared with the clinically based diagnosis, the weighted kappa coefficient was kappa = 0.567 (95% confidence interval [CI], 0.42-0.71) for the right eye and kappa = 0.516 (95% CI, 0.37-0.66) for the left eye. Best kappa coefficient of agreement was seen when normals were grouped with suspects in both clinical and MRA diagnosis (kappa = 0.604; 95% CI, 0.409-0.799 in the right eye). Depending on the gold standard and test-positive definitions for glaucoma, specificity ranged from 87% to 97%, sensitivity from 25% to 100%, PPV from 28% to 68%, NPV from 84% to 100%, PLR from 5.0 to 19.2, and NLR from 1.3 to 6.2. When CSM, HVC, and MRNFLT were compared with clinical diagnosis, all outcome measures were found to have lower ranges: specificity from 46.9% to 83.7%, sensitivity from 36.5% to 76.9%, PPV from 6% to 36%, NPV from 80% to 99%, PLR from 0.8 to 4.0, NLR from 0.9 to 3.0. The results of this study suggest that a glaucoma screening program may be effective in detecting glaucoma when targeting high-risk populations. Heidelberg Retina Tomograph II testing may prove to be a useful tool in detecting glaucomatous optic nerve damage and could be used as part of a complete glaucoma screening protocol.