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

PURPOSE: To analyze the cost and detection rate of a screening program for detecting glaucoma with imaging devices. MATERIALS AND METHODS: In 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. RESULTS: The 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. CONCLUSION: The proposed screening method directed at population at risk allows a detection rate of 4.1% and a cost of 1,410 per case detected.

Diagnostic accuracy of imaging devices in glaucoma: A meta-analysis.

Imaging devices such as the Heidelberg retinal tomograph-3 (HRT3), scanning laser polarimetry (GDx), and optical coherence tomography (OCT) play an important role in glaucoma diagnosis. A systematic search for evidence-based data was performed for prospective studies evaluating the diagnostic accuracy of HRT3, GDx, and OCT. The diagnostic odds ratio (DOR) was calculated. To compare the accuracy among instruments and parameters, a meta-analysis considering the hierarchical summary receiver-operating characteristic model was performed. The risk of bias was assessed using quality assessment of diagnostic accuracy studies, version 2. Studies in the context of screening programs were used for qualitative analysis. Eighty-six articles were included. The DOR values were 29.5 for OCT, 18.6 for GDx, and 13.9 for HRT. The heterogeneity analysis demonstrated statistically a significant influence of degree of damage and ethnicity. Studies analyzing patients with earlier glaucoma showed poorer results. The risk of bias was high for patient selection. Screening studies showed lower sensitivity values and similar specificity values when compared with those included in the meta-analysis. The classification capabilities of GDx, HRT, and OCT were high and similar across the 3 instruments. The highest estimated DOR was obtained with OCT. Diagnostic accuracy could be overestimated in studies including prediagnosed groups of subjects.

Utility of a Virtual Trier Social Stress Test: Initial Findings and Benchmarking Comparisons.

OBJECTIVE: The Trier Social Stress Test (TSST) is one of the most widely used laboratory-based acute psychosocial stressors. However, there may be advantages to conducting the TSST through the virtual world, including reducing the cost and burden (i.e., no need for colocation between the evaluators and participants). The virtual TSST might also increase the standardization between studies and provide the capacity to bring psychology experiments to more settings (e.g., the home, the magnetic resonance imaging scanner). METHODS: Fifty undergraduate students participated in the TSST conducted through an online virtual reality program, using a computer screen and microphone/earphone headset. RESULTS: The present study found that the virtual TSST produced a significant acute stress response, measured both through cortisol (F(1,128) = 31.91, p < .001) and subjective report (F(1,148) = 72.86, p < .001). In addition, this method differentially produced a dampened cortisol response (F(1,126) = 4.41, p < .04) in those who had experienced recent loss (e.g., bereavement, romantic breakup, homesickness), similar to prior research. CONCLUSIONS: Virtual reality-based administration of the TSST and other mental challenge protocols increases the possibilities of many standard psychological experiments relevant to biobehavioral research.

Comparison of retinal nerve fiber layer thickness values using Stratus Optical Coherence Tomography and Heidelberg Retina Tomograph-III.

PURPOSE: To evaluate the usefulness of retinal nerve fiber layer (RNFL) thickness measurements using the Heidelberg Retina Tomograph-III (HRT-III) in normal, ocular hypertensive, and glaucomatous eyes and compare the thickness measurements using HRT-III and Stratus Optical Coherence Tomography-3 (OCT-3). METHODS: Sixty-nine normal eyes, 60 eyes ocular hypertensive, and 111 glaucomatous were included. All participants underwent visual field, HRT-III, and OCT-3 examinations on the same day. Patients were classified into 3 groups according to intraocular pressure and visual field damage. The sensitivity/specificity of RNFL thickness measurements and RNFL thickness classifications using HRT-III and OCT-3 were calculated. The sensitivity/specificity of the height variation contour (HVC) from the HRT-III were calculated. The receiver operating characteristic curves (ROC) and areas under the ROC were plotted. Agreement was calculated using Bland-Altman method and the kappa coefficient. RESULTS: The RNFL thickness sensitivity/specificity were 32.4%/87%, for the HRT-III and 72.97%/81.15% for the OCT-3 in relation to the glaucoma diagnosis (least specific criteria). The RNFL thickness sensitivities/specificities were lower in early glaucoma. The areas under the ROC for RNFL measurements were 0.72 using HRT-III, 0.86 with OCT-3 (P=0.001), and 0.54 for the HVC. The RNFL classification kappa coefficient was 0.36. Bland-Altman analysis confirmed that the RNFL measurements were not interchangeable. CONCLUSIONS: The sensitivity of RNFL damage detection using HRT-III was lower compared with OCT-3, especially in early glaucoma. RNFL thickness agreement between HRT-III and OCT-3 was only fair. HVC was not useful for glaucoma detection.