Effect of signal strength on reproducibility of peripapillary retinal nerve fiber layer thickness measurement and its classification by time-domain optical coherence tomography.
OBJECTIVE
To assess the effect of signal strength (SS) on reproducibility of peripapillary retinal nerve fiber layer (RNFL) thickness measurement (measurement agreement) and its color-coded classification (classification agreement) by time-domain optical coherence tomography (OCT).


METHODS
Two consecutive Stratus OCT scans with the Fast RNFL protocol were performed in 658 participants. Intraclass correlations and the linear-weighted kappa coefficient were calculated as indicators of RNFL measurement and classification agreement in participants grouped according to the difference in SS between consecutive OCT scans (interscan SS difference).


RESULTS
Groups with a larger interscan SS difference (= 2) had lower measurement agreement than those with a smaller interscan SS difference (0 or 1) for the temporal quadrant and total average RNFL. Classification agreement for the nasal quadrant was lower in the groups with a larger interscan SS difference (= 2) than in those with a smaller interscan SS difference. The tendency of SS to affect classification and measurement agreement remained similar in the group with thinner RNFL thickness (≤85 μm), but not in the group with thicker RNFL.


CONCLUSIONS
Careful attention should be paid when comparing two or more OCT scans for RNFL thickness measurement or its color-coded classification as the agreement may be sensitive to SS differences.
Institute of Vision Research, Department of Ophthalmology, Yonsei University College of Medicine, Seoul, Korea.
Eun Suk
ES
Lee
Hyunjoong
H
Kim
Joon Mo
JM
Kim
D003430:Cross-Sectional Studies; D005260:Female; D005901:Glaucoma / Q000145:classification* / Q000175:diagnosis; D006801:Humans; D007429:Intraocular Pressure; D008297:Male; D008875:Middle Aged; D009412:Nerve Fibers / Q000473:pathology*; D009898:Optic Disk / Q000473:pathology*; D009901:Optic Nerve Diseases / Q000145:classification* / Q000175:diagnosis; D015203:Reproducibility of Results; D012165:Retinal Ganglion Cells / Q000473:pathology*; D041623:Tomography, Optical Coherence / Q000379:methods*; D014792:Visual Acuity