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Br J Ophthalmol. 2011 Oct;95(10):1410-4. doi: 10.1136/bjo.2009.175869. Epub 2011 Jan 17.

Single versus sequential testing with scanning peripheral anterior chamber depth analyser, IOLMaster and anterior segment optical coherence tomography for the detection of narrow angles.

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Wilmer Eye Institute, Johns Hopkins University, Baltimore, MD 21287, USA.



Scanning peripheral anterior chamber depth analyser (SPAC), IOLMaster and anterior segment optical coherence tomography (AS-OCT) are devices that can screen non-invasively for narrow angles (NAs) and may reduce the need for gonioscopy, especially where the availability of ophthalmologists is limited. When used individually to detect NAs, neither SPAC, AS-OCT nor IOLMaster were able to achieve both high sensitivity and specificity when using gonioscopy as a gold standard.


To assess whether sequential testing improves discrimination of NAs over single testing.


In a prospective community-based cross-sectional study in Singapore, 2047 phakic right eyes underwent SPAC, IOLMaster and AS-OCT. NA eyes were defined as present when Shaffer scores were 0 or 1 in ≥ 2 quadrants on gonioscopy. Sensitivities and specificities of single and sequential testing were compared.


At a fixed specificity of 95%, sensitivities in detecting NA eyes were 57.8% (95% CI 52.7% to 62.7%) for SPAC, 43.3% (95% CI 38.3% to 48.3%) for IOLMaster and 52.1% (95% CI 46.4% to 57.7%) for AS-OCT. After sequential testing using SPAC followed by AS-OCT, the sensitivity rose to 70.3% (95% CI 65.5% to 74.8%) while specificity remained at 94.3% (95% CI 93.1% to 95.4%), with sensitivity significantly higher than single testing alone (p<0.001).


Sequential testing significantly improves the accuracy of detecting NAs and may be useful in screening settings.

[Indexed for MEDLINE]

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