Abstract
Purpose: :
To evaluate the distribution of central anterior chamber depth (CACD) and peripheral anterior chamber depth (PACD) using scanning peripheral anterior chamber depth analyzer (SPAC) in a population in a southern island of Japan and to compare SPAC with gonioscopy in identifying people with occludable angles (OAs).
Methods: :
3762 persons participated (participation ratio 81.2%) from 40 years or older population of Kumejima Town. All subjects underwent examination with SPAC and gonioscopy was performed by ophthalmologists masked to the SPAC findings. The area under the curve (AUC) was generated to assess the performance of these tests in detecting people with OAs. Eyes were as OAs by gonioscopy if the trabecular meshwork could be seen for ≤3 quadrants of the angle circumference.
Results: :
Reliable ACD measurements were obtained using SPAC from 2960 participants. The prevalence an OAs in right eye by gonioscopy was 12.9% (384subjects). The CACD and PACD grade averaged 3.0+/- 0.5 mm and 7.6 +/- 2.2 (mean +/- standard deviation), and was smaller in occludable angles (2.6 ±0.4mm, 5.4 +/- 1.8) than open angles (3.1 ± 0.4mm , 7.9 +/- 2.0) respectively (P<0.001). The AUC for the SPAC using a numeric grade, peripheral anterior chamber angle measured from 3 points and CACD by SPAC were 0.82 (95% CI, 0.80-0.84), 0.64 (95% CI, 0.61-0.67) and 0.81 (95% CI, 0.79-0.83), respectively. The sensitivity using a cutoff with SPAC grade equal or less than 5, equal or less than 6 and at a cutoff of 2.95mm for CACD were 50.5%, 75.5% and 82.6%, with specificity 89.7%, 76.0% and 65.1%, respectively. The sensitivity of SPAC using categoric grades S or P and a combined grade of grades of <5 and categoric grades S or P was 55.9 % and 56.5%, with a specificity 84.6% and 84.1%, respectively.
Conclusions: :
The relatively weak performance of detecting OAs found with the SPAC may limit the usefulness of this device in screening for subjects in Kumejima town. For screening to identify participants by SPAC as having OAs, additional consideration about criteria is needed.
Keywords: clinical (human) or epidemiologic studies: systems/equipment/techniques • anterior chamber • imaging/image analysis: clinical