A comparison of HRT II and GDx imaging for glaucoma detection in a primary care eye clinic setting

Abstract

Purpose To evaluate the performance of the HRT II (Heidelberg retinal tomograph) and GDx (glaucoma detection) retinal nerve fibre analyzer in GDx when used in the primary care eye clinic setting for glaucoma screening. Patients and Methods The study was prospective, cross-sectional, and hospitalbased. One-hundred and twelve patients, 59 women and 53 men with a mean age of 57.8 years (range 18-85 years), had consecutive HRT II disc imaging and GDx retinal nerve fiber layer analysis. The Moorfield's regression classification and the 'GDx number' were used to predict the likelihood of glaucoma. A separate clinician, masked to the instrument results determined a definitive diagnosis, based on clinical examination. The extent of agreement between instrument prediction and the clinician diagnosis of glaucoma was examined by generating sensitivity and specificity tables. Results The HRT II had a sensitivity of 0.79 (95% CI: 0.60-0.92) and a specificity of 0.70 (95% CI: 0.60-0.78). The positive predictive value of the HRT II was 0.43 (95% CI: 0.29-0.57). Using a GDx number of 50 as 'cutoff' for glaucoma detection, the GDx had a sensitivity of 0.80 (95% CI: 0.59-0.93) and a specificity of 0.72 (95% CI: 0.61-0.80), with a positive predictive value of 0.43 (95% CI: 0.28-0.59). Conclusions For glaucoma detection, neither the HRT II nor the GDx are effective as stand-alone screening devices in the primary care setting.

Macular imaging with optical coherence tomography in glaucoma

“…86,121 Several imaging tools were explored over the last 3 decades and found to be potentially useful for the diagnosis and management of glaucoma. 8,9,15,38,74,127,244,254,286,340,349,363 Optical coherence tomography (OCT) has become the structural imaging technology of choice for glaucoma diagnostics due to the speed of acquisition, high resolution, and excellent reproducibility. 88,342 It generates cross-sectional images of the posterior segment by measuring the echo time delay and the magnitude of backscattered light reflected off the retina or the ONH through the principle of lowcoherence interferometry.…”

Descripción y análisis de las tecnologías diagnósticas OCT, HRT y GDx en glaucoma: un enfoque para la optometría clínica

“…Actualmente, se conocen el HRT I o el clásico, el HRT II y el HRT III. El HRT I fue el primero de su generación; obtiene una serie de imágenes en conjunto (32 imágenes en sección óptica) independientemente de la profundidad de exploración y tiene una resolución axial variable de 62 a 128 µm entre las secciones ópticas (Balasubramanian et al, 2011;Andreou et al, 2007). Desviación estándar (standart deviation [SD]).…”

“…Finalmente, se construye así una imagen con cada pixel, que corresponde a un valor de retardo en la localización de la exploración, traducida a código de colores. Se afirma que 0,67 nm de retraso equivalen a 1 µm de espesor retinal (Sánchez, 2013;Tóth et al, 2008;Andreou et al, 2007).…”

Conditional GAN for Prediction of Glaucoma Progression with Macular Optical Coherence Tomography

“…Due to the progressive and asymptomatic nature of glaucoma, it is crucial for clinicians to diagnose it in its early stages and be able to detect its progression in a timely manner to prevent the progressive functional loss [5][6][7][8][9]. Glaucoma progression can be evaluated with structural and functional measures [10][11][12][13][14][15][16][17]. The estimation of glaucoma progression is challenging as the rate of disease progression varies among individuals [18].…”