AC angle & depth assessment with Pen torch

Assessment of the anterior chamber angle (ACA) and ant erior chamber depth (ACD) is necessary for several reasons. Many types of glaucoma require ACA assessment for a correct diagnosis eg, narrow angle glaucoma, angle closure glaucoma, pigmentary glaucoma and neovascular (or 100- day) glaucoma. Visualisation of the angle is also recommended where there is any suspicion of peripheral anterior synechiae, angle recession or iridodialysis post-trauma. It is also useful for establishing the patency of peripheral iridotomies and a patient’s suitability for anterior chamber implants. In everyday practice it is useful to know the width of the angle to help determine the potential risk of angle closure prior to carrying out pupil dilation on a patient. This article describes the pentorch methods that can be used to assess the ACA and/or ACD in clinical practice.


Pen torch method

The simplest method of assessing ACD is by shining a pen torch into the patient’s eye from the temporal canthus such that the pen torch lies in the same plane as the eye. In the case of a deep anterior chamber, the iris lies flat and the whole iris will be illuminated. In the case of a very shallow anterior chamber the iris lies forward, blocking some of the light and very little of the iris is illuminated. Based on the amount of eye illuminated the ACD can be graded