Assessment of Anterior Chamber Angles

1
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.
  2004881030-1035
• 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.
  2004881036-1041
• Finding cases of angle closure glaucoma in clinic
  setting using a newly developed instrument.
• Kashiwagi K et al. Eye. 2006 Mar20(3)319-24
• No studies so far to compare the gradings of SPAC
  versus that of gonioscopic findings with
  shaffers 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 Shaffers 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
P0.100
10
Comparison of SPAC vs Race
P0.101
11
Comparison of SPAC vs Gonioscopy
Plt0.001
12
Correlation of SPAC and Gonioscopy

• Spearmans correlation coefficient
• (r) 0.699
• (plt0.001)

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.

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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.

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Thank you