Detection of glaucoma using operator-dependent versus operator-independent classification in the Heidelberg retinal tomograph-III

Abstract

Objective: To compare the abilities of a new Glaucoma Probability Scoring (GPS) system and Moorfields regression analysis (MRA) to differentiate between glaucomatous and normal eyes using Heidelberg retinal tomograph (HRT)-III software and race-specific databases. Methods: In this prospective study, one eye (refractive error (5 D) each of consecutive normal patients and those with glaucoma was enrolled. All patients underwent a full eye examination, standard achromatic perimetry (Swedish Interactive Threshold Algorithm-standard automated perimetry (SITA-SAP), program 24-2) and confocal scanning laser ophthalmoscopy (HRT-II) within 1 month. Normal patients had two normal visual fields in both eyes (pattern standard deviation (PSD) .5% and Glaucoma Hemifield Test within 97% normal limits) and a normal clinical examination. Glaucoma was defined on the basis of SITA-SAP visual field loss (PSD,5% or Glaucoma Hemifield Test outside normal limits) on two consecutive visual fields. HRT-II examinations were exported to the HRT-III software (V.3.0), which uses an enlarged race-specific database, consisting of 733 eyes of white people and 215 eyes of black people. Race-adjusted MRA for the most abnormal sector (operator-dependent contour line placement) was compared with the global race-adjusted GPS (operator independent). MRA sectors outside the 99.9% confidence interval limits (outside normal limits) and GPS >0.64 were considered abnormal. Results: 136 normal patients (72 black and 64 white patients) and 84 patients with glaucoma (52 black and 32 white patients) were enrolled (mean age 50.4 (SD 14.4) years). The average visual field mean deviation was 20.4 (SD 1.1) db for the normal group and 27.3 (SD 6.7) db for the glaucoma group (p,0.001). Mean GPS values were 0.21 (SD 0.23) and 0.73 (SD 0.27) for normal and glaucomatous eyes, respectively (p,0.001). Sensitivity and specificity values were 77.1% and 90.3% for GPS, and 71.4% and 91.9% for MRA, respectively. Conclusions: In this cohort, GPS software sensitivity and specificity values are similar to those of MRA, which requires placement of an operator-dependent contour line. The development of software to detect glaucoma without a contour line is critical to improving the potential use of HRT as a tool for glaucoma detection and screening.

Comparison of Diagnostic Accuracy of Heidelberg Retina Tomograph II and Heidelberg Retina Tomograph 3 to Discriminate Glaucomatous and Nonglaucomatous Eyes

“…These findings are similar with prior reports. 11,12 Zelefsky et al found no differences between HRT II and HRT 3 MRA in African and European ancestry groups. However, the authors found greater variation in sensitivity and specificity for subjects of African ancestry.…”

“…10 Recent studies have shown similar to improved discriminatory ability of HRT 3 than HRT II. [11][12][13][14] Zelesfky et al found increased sensitivity in subjects with European and African ancestry using HRT 3. 11 These studies, however, were done with groups of glaucoma patients older than controls, the effect of age was not included, and racial comparisons were not performed.…”

Performance of colour Doppler imaging discriminating normal tension glaucoma from healthy eyes

“…For comparison, the detection of glaucoma using optic disc analysis aims to reveal changes of the optic disc as being key criteria for glaucoma diagnosis. Harizman et al 34 recently published a study that evaluates the sensitivity of the Heidelberg Retina Tomograph III to detect glaucomatous optic disc damage in perimetric glaucoma. Sensitivity of the Moorfields regression analysis was 71.4 at 91.9% specificity.…”

Glokom Hastalarında HRT III Cihazında MRA ve GPS Algoritmalarının Tanısal Değerlerinin Karşılaştırılması

“…GPS yöntemi iki adet parapapiller RSLT şekli ölçümü (yatay ve dikey RSLT eğriliği) ve üç adet OSB şeklini (çukurluk boyutu, çukurluk derinliği ve rim dikliği) kullanarak glokom olasılığını sınıflar (normal sınırlar içinde, sınırda ve normal sınırlar dışında). [6][7][8] GPS algoritması optik disk snırlarını belirleyen bir operatöre ve bir referans planına gerek duymadığından tanısal değerinin MRA'dan daha yüksek olması beklenebilir.…”