Purpose:
To describe the use of anterior segment optical coherence tomography (AS-OCT) in studying the dynamic changes of the anterior chamber angle by corneal indentation.
Methods:
In a prospective observational study, the anterior segments of 21 eyes of 16 patients were imaged using the 3D OCT-1000 (Topcon, Tokyo, Japan) and Lin50 UBM Aviso (Quantel Medical, Les Ulis, France). Complete imaging of the anterior segment was achieved by slit-lamp biomicroscopy, gonioscopy and AS-OCT. After a first static exam on nasal and temporal edge, a second one was executed on the same areas with a central corneal indentation. An evaluation of the reopening of the angle and its measure were performed.
Results:
A total of 17 eyes had abnormal angle configurations including narrow or closed angles, and 4 had normal angle configurations as determined by prior full ophthalmic examination. All the ACA were well examined with sufficient visibility, and all plateau iris were easily diagnosed by the AS-OCT.The measures were significantly increased after indentation. In non indented situation (nasal and temporal angles), mean angle was 9.8° (5.8SD) and increase to 16.4° (4.6SD) (p<0.0001, Mann-Whitney U-test) after indentation. This increasing was also significant between non indented and indented angles in nasal (respectively 10° to 16.2°, p=0.013, Mann-Whitney U-test) and temporal (respectively 9.6° to 16.6°, p=0.004, Mann-Whitney U-test) subgroups.
Conclusions:
This method would appear to offer a non-contact, convenient and rapid method of assessing the configuration of the anterior chamber; it may be of help during the routine clinical assessment and treatment of patients with narrow or closed angles, particularly when gonioscopy is not possible or is difficult to interpret.
Keywords: imaging/image analysis: clinical • anterior chamber • anterior segment