1. Johnson CH TAN, MBBS, MRCSEd(Ophthalmology)
Assessment of Anterior Chamber Angles – Scanning Peripheral Anterior Chamber Depth Analyser (SPAC) compared to Gonioscopy 
Johnson CH TAN, MBBS, MRCSEd(Ophthalmology)
Colin SH TAN, MBBS, M Med (Ophthalmology), MRCSEd (Ophthalmology), FAMS
The authors have no financial interest in any of the products mentioned

2. Literature Review
A newly developed peripheral anterior chamber depth analysis system: principle, accuracy, and reproducibility.
K Kashiwagi et al. Br. J. Ophthalmol. 2004;88;
Computer installed program automatically evaluate the ACD, CT and CRC.
Dummy eye was used for investigation.
3 examiners measured ACD in 10 normal eyes (shaffers’ grade 3 or 4) and inter-observer and intra-obserever reproducibility analysed.

3. Literature Review
Quantitative evaluation of changes in anterior segment biometry by peripheral laser iridotomy using newly developed scanning peripheral anterior chamber depth analyser.
K Kashiwagi et al. Br. J. Ophthalmol. 2004;88;
Finding cases of angle closure glaucoma in clinic setting using a newly developed instrument.
Kashiwagi K et al. Eye Mar;20(3);319-24
No studies so far to compare the gradings of SPAC versus that of gonioscopic findings with shaffer’s grading.

4. Objective
To assess the correlation between the scanning peripheral anterior chamber depth analyser (SPAC) and gonioscopy in the assessment of the anterior chamber angles. 

5. Method
Prospective analytical study performed at Tan Tock Seng Hospital, Singapore.
The temporal anterior chamber angles of patients seen at the ophthalmology outpatient clinic were assessed by SPAC (graded from 1 to 12) and gonioscopy performed by a single masked investigator using the Shaffer’s grading (grades 1 to 4).

6. Method Exclusion criteria :
Patients with peripheral corneal disease. obstructing the view of the angles
peripheral anterior synechiae.
patients whose pupils were pharmacologically dilated.

7. Results

8. Demographics
Age distribution
Mean 60.6 (SD ±12.6), range 38-83
N = 37

9. Comparison of SPAC vs Sex

10. Comparison of SPAC vs Race

11. Comparison of SPAC vs Gonioscopy

12. Correlation of SPAC and Gonioscopy
Spearman’s correlation coefficient
(r) = 0.699
(p<0.001)

13. Discussions
Gonioscopy remains the gold standard in evaluating the angles.
However, subjected to inter-observer and intra-observer variability.
Limitations of SPAC : unable to pick up peripheral anterior synechiae.

14. Conclusion SPAC correlates well with the gradings of gonioscopy.
All gonioscopy gradings of 2 or less have SPAC grades of 6 or less.
But some with gonioscopy gradings of 3 or more have SPAC grades of 6 or less.
Performing gonioscopy on SPAC grades of 6 or less appears to pick up the narrow angles.

15. Thank you