Interobserver and Intertest Agreement in Telemedicine Glaucoma Screening with Optic Disk Photos and Optical Coherence Tomography

Agreement between Five Experts and the Laguna ONhE Automatic Colourimetric Application Interpreting the Glaucomatous Aspect of the Optic Nerve

BACKGROUND

Optic nerve head (ONH) interpretation is a glaucoma screening method which may be influenced by criteria variability. Laguna ONhE software is a low-cost and non-invasive method of ONH analysis.

METHODS

We analysed the results of the Laguna ONhE application, interpreting 552 ONH images from the ACRIMA database, publicly available on the Internet, and compared them with the opinion of five experts. Diagnostic agreement was investigated using Cohen's kappa (κ) with 95% confidence.

RESULTS

The kappa concordance index obtained with Laguna ONhE and the majority of the experts' criterion (0.77) was significantly higher compared to that obtained with ACRIMA and the majority of the experts' criterion (0.61). In 44.7% of the cases there was absolute agreement among the 5 experts and the Laguna ONhE program. Removing borderline cases from the analysis yielded increased diagnostic agreement (0.81). The area under the receiver operating characteristic (AUROC) of the Laguna ONhE program (0.953, p < 0.001) was not significantly different than AUROC of the majority of the experts' criterion (0.925, p < 0.001), p = 0.052. Individually obtained expert's AUROCs were significantly lower (0.636 to 0.913; p < 0.01).

CONCLUSIONS

Laguna ONhE's agreement with the experts is high, particularly where the diagnosis may be more obvious by the appearance of the ONH.

Cost-Effectiveness of Screening for Open Angle Glaucoma Compared With Opportunistic Case Finding

PRCIS

The manuscript evaluates cost-effectiveness of glaucoma screening with imaging devices and telemedicine based on a screening campaign performed in Spain. The screening strategy implemented in our analysis was cost-effective compared with opportunistic case finding.

INTRODUCTION

Open angle glaucoma is an asymptomatic ocular disease that represents one of the first causes of blindness. Diagnosis is currently made by opportunistic case finding, usually by community optometrists or general ophthalmologists. The aim of this study was to assess the cost-effectiveness of a screening strategy based on optical coherence tomography and fundus photographs in glaucoma detection.

MATERIALS AND METHODS

A cost-effectiveness analysis was carried out to compare 2 alternative strategies: opportunistic finding versus screening. A Markov tree model was carried out with 10 health states according to disease progression. Quality-adjusted life years (QALYs) were used as a measure of effectiveness. We included short-term and long-term direct health costs and a discount rate of 3%. We performed a probabilistic sensitivity analysis and several 1-way sensitivity analyses.

RESULTS

The cohort in the screening program entailed an increase in 0.097 QALYs and additional costs of €1187 versus opportunistic finding, with an incremental cost-effectiveness ratio of about €12.214/QALY. The 1-way sensitivity analysis showed that inputs related to age and screening program (cost and detection rate) were those most strongly influencing the results of the analysis. Probabilistic sensitivity analyses showed that the model was robust to significant changes in the main variables of the analysis.

CONCLUSIONS

The screening strategy implemented in our analysis was cost-effective compared with opportunistic finding in patients with glaucoma in this Spanish setting.

Diagnostic Accuracy and Detection Rate of Glaucoma Screening with Optic Disk Photos, Optical Coherence Tomography Images, and Telemedicine

Purpose: The aim of this study was to evaluate the diagnostic accuracy of optical coherence tomography (OCT) and retinography in the detection of glaucoma through a telemedicine program. Methods: A population-based sample of 4113 persons was randomly selected. The screening examination included a fundus photograph and OCT images. Images were evaluated on a deferred basis. All participants were then invited to a complete glaucoma examination, including gonioscopy, visual field, and dilated fundus examination. The detection rate, sensitivity, specificity, and positive and negative predictive values were calculated. Results: We screened 1006 persons. Of these, 201 (19.9%) were classified as glaucoma suspects; 20.4% were identified only by retinographs, 11.9% only by OCT images, and 46.3% by both. On ophthalmic examination at the hospital (n = 481), confirmed glaucoma was found in 58 (12.1%), probable glaucoma in 76 (15.8%), and ocular hypertension in 10 (2.1%), and no evidence of glaucoma was found in 337 (70.0%). The detection rate for confirmed or probable glaucoma was 9.2%. Sensitivity ranged from 69.4% to 86.2% and specificity from 82.1% to 97.4%, depending on the definition applied. Conclusions: The combination of OCT images and fundus photographs yielded a detection rate of 9.2% in a population-based screening program with moderate sensitivity, high specificity, and predictive values of 84–96%.