Anterior Chamber Measurements Taken with Pentacam: An Objective Tool in Laser Iridotomy

Abstract

This study confirms previous reports of increased anterior chamber volume and angle after LPI and Pentacam is a good objective instrument to demonstrate the efficacy of LPI.

Changes of anterior chamber architecture induced by laser peripheral iridotomy in acute angle closure crisis

“…Using Scheimpflug photography in a group of 37 Canadian primary angle closure suspects, LPI leads to a significant increase of ACV and ACA but left ACD unchanged [21]. The same was previously described in a group of 20 Italian patients who underwent LPI due to a high risk of developing acute angle closure [22]. Jain et al [23] found in 68 patients of Indian descent which were treated with LPI for primary angle closure that LPI leads to a significant increase of ACV and peripheral anterior chamber depth but not central Fig.…”

The Course of the Changes in Anterior Chamber Parameters After Laser Peripheral Iridotomy

“…Our findings agree with previous studies regarding the increase in ACV and ACA. 5,[20][21][22][23] In contrast, it is controversial whether LPI deepens the CACD or not. 21 reported a significant increase in CACD after pilocarpine administration.…”

“…The changes in ACA, CACD, peripheral AC depth, and central corneal thickness have been documented previously. 5,[20][21][22][23] The device used in these studies is almost always the Pentacam (Oculus; Optikgera¨te GmbH, Wetzlar, Germany), which has been shown to be accurate and reproducible in quantifying AC parameters. 27 In our study we used the Sirius device, which is basically similar albeit slightly different, and as far as we know it has not been used previously in the evaluation of AC parameters after LPI.…”

“…Rather than direct visualization as in Pentacam, the Sirius-Scheimpflug provides angle calculation based on interpolation or extrapolation. 22 According to device user manual, only 7 of 25 scans intercepting the meridian 180 ± 20 degrees of nasal and temporal iridocorneal periphery are processed for averaging in ACA calculation, whereas the superior and inferior quadrants are not taken into consideration. Approximately 270 of 360 degrees of the entire ACA is ignored.…”

“…The changes were documented with the use of different imaging techniques such as gonioscopy, ultrasound biometry, anterior segment optical coherence tomography (AS-OCT), and Scheimpflug photography. 5,[11][12][13][14][15][16][17][18][19][20][21][22][23] Gonioscopy is still an invaluable clinical tool in the diagnosis of ACG. 5 However, its variable reproducibility, potential for inducing angle distortion through contact application, and the need for a skilled examiner limit its use as an objective quantitative measure.…”