Optic disc classification by the Heidelberg Retina Tomograph and by physicians with varying experience of glaucoma

PurposeTo compare the diagnostic accuracy of the Heidelberg Retina Tomograph's (HRT) Moorfields regression analysis (MRA) and glaucoma probability score (GPS) with that of subjective grading of optic disc photographs performed by ophthalmologists with varying experience of glaucoma and by ophthalmology residents.MethodsDigitized disc photographs and HRT images from 97 glaucoma patients with visual field defects and 138 healthy individuals were classified as either within normal limits (WNL), borderline (BL), or outside normal limits (ONL). Sensitivity and specificity were compared for MRA, GPS, and the physicians. Analyses were also made according to disc size and for advanced visual field loss.ResultsForty-five physicians participated. When BL results were regarded as normal, sensitivity was significantly higher (P<5%) for both MRA and GPS compared with the average physician, 87%, 79%, and 62%, respectively. Specificity ranged from 86% for MRA to 97% for general ophthalmologists, but the differences were not significant. In eyes with small discs, sensitivity was 75% for MRA, 60% for the average doctor, and 25% for GPS; in eyes with large discs, sensitivity was 100% for both GPS and MRA, but only 68% for physicians.ConclusionOur results suggest that sensitivity of MRA is superior to that of the average physician, but not that of glaucoma experts. MRA correctly classified all eyes with advanced glaucoma and showed the best sensitivity in eyes with small optic discs

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

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 −0.4 (SD 1.1) db for the normal group and −7.3 (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

Axial length and optic disc size in normal eyes

AIM: To investigate the relationship between optic disc area and axial length in normal eyes of white and black people. METHODS: Consecutive eligible normal subjects were enrolled. Ocular biometry was obtained using A‐scan ultrasonography, and reliable images of the optic disc were obtained using a confocal scanning laser ophthalmoscope. The relationship between optic disc area and axial length was assessed using univariate and multivariate models. RESULTS: 281 eyes of 281 subjects were enrolled. Black subjects (n = 157) had significantly larger discs (mean (SD) disc area, 2.12 (0.5) mm(2)) than white subjects (n = 124; 1.97 (0.6) mm(2); t test, p = 0.02). Optic disc area increased with axial length (Pearson's correlation coefficient, r = 0.13, p<0.035) for the entire study population. Multivariate regression models including race, disc area and axial length showed that a significant but weak linear relationship exists between axial length and disc area (partial correlation coefficient 0.14; p<0.024), and with race and disc area (partial correlation coefficient 0.19; p<0.017) when adjusted for the effects of other terms in the model. CONCLUSION: Increased disc area is associated with longer axial length measurements and African ancestry. This may have implications for pathophysiology and risk assessment of glaucoma

Structural and functional assessment of the macular region in patients with glaucoma

PURPOSE: To investigate the correlation of a structural measure of the macular area (optical coherence tomography (OCT)) with two functional measures (10‐2 Humphrey visual field (HVF) and multifocal visual evoked potential (mfVEP)) of macular function. METHODS: 55 eyes with open‐angle glaucoma were enrolled. The 10‐2 HVF was defined as abnormal if clusters of ⩾3 points with p<5%, one of which had p<1%, were present. The mfVEP was abnormal if probability plots had ⩾2 adjacent points with p<1%, or ⩾3 adjacent points with p<5% and at least one of these points with p<1%. Two criteria were used for the macular OCT: (I) ⩾2 sectors with p<5% or 1 sector with p<1% and (II) 1 sector with p<5%. RESULTS: 54 of the 55 eyes showed an abnormal 10‐2 HVF and 50 had central mfVEP defects. The two OCT criteria resulted in sensitivities of 85% and 91%. When both functional tests showed a defect (in 49 eyes), the OCT was abnormal in 45. For the OCT the outer and inner inferior regions were the most likely to be abnormal, and both functional techniques were most abnormal in the superior hemifield. CONCLUSIONS: Good agreement exists between macular thickness and functional defects in patients with glaucoma. Study of the macular region may provide a quantitative measure for disease staging and monitoring