Optical biometry of the anterior eye segment: interexaminer and intraexaminer reliability of ACMaster.
OBJECTIVE
To evaluate the interexaminer and intraexaminer reliability of corneal thickness, anterior chamber depth (ACD), and crystalline lens thickness measurements using a commercially available anterior segment optical biometry instrument (ACMaster, Carl Zeiss Meditec) based on partial coherence interferometry (PCI).


METHODS
Medical University of Vienna, Vienna, Austria.


METHODS
Interexaminer reliability and intraexaminer reliability were evaluated in 10 eyes of 10 young volunteers and 11 eyes of 11 cataract patients. The measurements of the interexaminer reliability were taken by 3 examiners. Corneal thickness, ACD, and lens thickness of the intraexaminer reliability were measured twice in all eyes by 1 examiner. To evaluate the effect of cycloplegia on the variability, the measurements were performed on 5 volunteers under cyclopentolate 1%. Measurements were performed using the prototype of the ACMaster based on PCI.


RESULTS
The interexaminer/intraexaminer reliabilities were 99.9% for corneal thickness and ACD. The reliability of lens thickness could not be estimated because of a large number of missing values in the cataract patient group. The median interexaminer variability (SD) was 1.9 microm for corneal thickness, 7.5 microm for ACD, and 10.6 microm for lens thickness. The median intraexaminer variability (SD) was 1.6 microm for corneal thickness, 10.8 microm for ACD, and 8.7 microm for lens thickness. With cycloplegia, both the interexaminer variability and intraexaminer variability were smaller than without cycloplegia.


CONCLUSIONS
Partial coherence interferometry measurements of anterior chamber distances (corneal thickness, ACD, lens thickness) using the prototype of ACMaster were highly reliable, allowing examiner-independent measurements. However, lens thickness measurements in cataract eyes were often difficult.
Department of Ophthalmology, Section of Clinical Biometrics, Medical University of Vienna, Vienna, Austria.
Stefan
S
Sacu
Oliver
O
Findl
Wolf
W
Buehl
Barbara
B
Kiss
Andreas
A
Gleiss
Wolfgang
W
Drexler
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000869:Anterior Eye Segment / Q000473:pathology*; D001699:Biometry / Q000379:methods*; D002386:Cataract / Q000473:pathology; D003519:Cyclopentolate / Q000008:administration & dosage; D003941:Diagnostic Techniques, Ophthalmological / Q000295:instrumentation; D005260:Female; D006801:Humans; D007368:Interferometry; D007908:Lens, Crystalline / Q000473:pathology; D008027:Light; D008297:Male; D008875:Middle Aged; D009184:Mydriatics / Q000008:administration & dosage; D015588:Observer Variation; D011680:Pupil / Q000187:drug effects; D015203:Reproducibility of Results
D009184:Mydriatics; D003519:Cyclopentolate