ROC analysis of Heidelberg Retina Tomograph optic disc shape measures in glaucoma.
OBJECTIVE
To determine the capacity of the Heidelberg Retina Tomograph (HRT) optic disc shape measures to detect glaucomatous damage.


METHODS
Prospective study.


METHODS
Department of ophthalmology at a university-affiliated hospital in Vancouver.


METHODS
Ninety-seven consecutive patients from the glaucoma centre and 129 healthy subjects selected from volunteers and employees of the department. One eye of each subject was chosen randomly.


METHODS
Visual fields, as assessed with the Humphrey perimeter, program 30-2, and 12 HRT shape characteristics: disc area, cup area cup/disc area ratio, rim area, cup volume, rim volume, mean cup depth, maximum cup depth, cup shape measure, height variation contour, mean retinal nerve fibre layer thickness and retinal nerve fiber layer cross-section area. ROC (receiver operating characteristic) curves were used to analyse the capacity of each HRT characteristic to detect glaucoma.


RESULTS
Statistically significant difference were found between the control and glaucoma groups in age, cup area, cup/disc ratio, rim area, cup volume, rim volume, mean cup depth, cup shape measure, mean retinal nerve fibre layer thickness and retinal nerve fibre layer cross-section area (p < or = 0.003, t-test). The largest (i.e., best) ROC curve area was found for cup shape measure (area = 0.812), rim area (0.809), cup/disc area ratio (0.804) and rim volume (0.768). The mean reference height was 0.31 mm (standard deviation [SD] 0.14 mm) for the control group and 0.29 mm (SD 0.12 mm) for the glaucoma group, a nonsignificant difference.


CONCLUSIONS
Cup shape measure was the most predictive HRT shape characteristic.
Iester
M
M
Department of Ophthalmology, University of British Columbia, Vancouver.
Mikelberg
F S
FS
Swindale
N V
NV
Drance
S M
SM
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005189:False Positive Reactions; D005901:Glaucoma / Q000473:pathology*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008875:Middle Aged; D009898:Optic Disk / Q000473:pathology*; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012372:ROC Curve; D011897:Random Allocation; D015203:Reproducibility of Results; D012160:Retina / Q000473:pathology; D014054:Tomography / Q000379:methods*; D058609:Visual Field Tests; D014794:Visual Fields