Noncontact corneal pachymetry with slit lamp-adapted optical coherence tomography.
OBJECTIVE
The purpose of this study was to determine the accuracy, the reproducibility, and the limits of agreement of noncontact central corneal thickness measurement with slit lamp-adapted optical coherence tomography (OCT).


METHODS
Nonrandomized comparative clinical trial.


METHODS
In a prospective comparative observational study, a total of 108 consecutive patients (108 eyes) with normal corneas (92 eyes) and different corneal alterations (16 eyes) participated. Six sequential measurements of the central corneal thickness with slit lamp-adapted OCT and with ultrasound (US) pachymetry at 1640 ms(-1) were performed. The main outcome measures were accuracy, reproducibility assessed with precision and coefficient of variation (CV), and limits of agreement of central corneal thickness measurement.


RESULTS
The mean central corneal thickness values were 541 +/- 43 microm (OCT) and 549 +/- 44 microm (US) with a mean precision of +/- 5.8 microm (CV 1.08%) and of +/- 4.0 microm (CV 0.73%), respectively. The method comparison revealed equivalence (+/- 2SD) in the 5% range with a mean difference between both methods of 7.9 microm (1.45%). The relative error was 8.7 microm (1.6%), which corresponded to limits of agreement (+/- 2SD) ranging from -9.5 microm to 25.3 microm.


CONCLUSIONS
Central corneal pachymetry with slit lamp-adapted OCT revealed, for clinical purposes, an excellent accuracy and reproducibility with a high degree of agreement compared with US pachymetry. Thus, the presented OCT system seems to be a promising diagnostic modality to objectively measure corneal thickness in a convenient noncontact mode.
Wirbelauer
Christopher
C
Klinik für Augenheilkunde, Vivantes-Klinikum Neukölln, Berlin, Germany.
Scholz
Christian
C
Hoerauf
Hans
H
Pham
Duy Thoai
DT
Laqua
Horst
H
Birngruber
Reginald
R
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003315:Cornea / Q000033:anatomy & histology* / Q000000981:diagnostic imaging / Q000473:pathology; D003316:Corneal Diseases / Q000473:pathology; D003941:Diagnostic Techniques, Ophthalmological; D005260:Female; D006801:Humans; D007368:Interferometry; D008027:Light; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D015203:Reproducibility of Results; D014054:Tomography / Q000379:methods; D014463:Ultrasonography