University of Iowa Health Care

Ophthalmology and Visual Sciences

Techniques for Difficult Angles

Examine the Inferior Angle: The inferior angle is the deepest and the most pigmented. Often the anatomy is most clearly defined in the inferior angle because the pigmentation highlights the posterior (pigmented) trabecular meshwork. Once the relationship between structures is established in the lower angle (superior mirror) this information can help the examiner with the interpretation of the remainder of the angle.

Introduction - Look over the Hill: Sometimes the iris is bowed forward making visualization of the iridocorneal angle quite challenging. In many of these eyes the angle is open but the iris bowing obscures the view (Figure 1). This was a bigger problem when cholinergic agents, such as pilocarpine, were commonly used. One can have the patient look into the examining mirror or tip the lens towards the angle being examined to look over the hill and into the angle. In general, if one can readily see over the hill and into the angle without indenting, the angle is not occludable.

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Introduction - Corneal Wedge

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Introduction - Indentation

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Introduction - The Other Eye: One should always examine both eyes. This can be very helpful in patients with presumed pupillary block angle closure in one eye. If corneal edema precules a view of the iridocorneal angle looking at the fellow eye can be instructive. If the opposite eye has a wide-open angle one might need to reconsider diagnosis. Similarly, angle recession can be difficult to differentiate from the deep anterior chambers of highly myopic eyes. Comparing the two eyes can help to make the appropriate diagnosis.

Introduction - Van Herick

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