Variability across the optic nerve head in scanning laser tomography.

AIM To characterise measurement variability in scanning laser tomography of the optic nerve head. METHODS 21 normal and 21 glaucoma subjects underwent same and separate day test-retest Heidelberg retina tomograph imaging by the same and different operators. RESULTS Rim area was most reproducible among parameters. Its variability tended to be highest temporally and increased (p<0.05) with testing involving different operators and visits. Nature of regional variability differed between glaucoma and normal eyes and between standard and 320 micro m reference planes. CONCLUSIONS Rim area is reproducible and potentially useful as a marker of progression. Pattern of variability and the influence of different reference planes, disease, operators, and visits should be considered when evaluating progression.