Clinical Routine

Clinical routine

Prior to dilation, it is important to:
1) Estimate angle of anterior chamber
The below picture showcases the difference between a close and open anterior chamber.

3 Tests, namely the Penlight Shadow Test, Van Herick’s Technique and Gonioscopy are used to estimate if the angle is closed or open.

Penlight Shadow test

A simple test using a penlight helps determine the risk for acute closed-angle glaucoma. A beam of light is directed from the side of the face toward the patient's iris. If no shadow appears on the nose, then most likely the angle is wide enough to dilate.

Van Herick technique

The Van Herick Technique is a slit-lamp estimation of the angle depth. First set the slit beam to very bright and thin. Then offset the beam temporally to the slit lamp oculars. Illuminate the temporal sclera and bring the slit lamp beam slowly towards the cornea until the anterior chamber is first identified. The thickness of the cornea is compared to the depth of the peripheral anterior chamber. If the anterior chamber depth is as deep as the cornea is thick then the angle is presumed to be wide open. If there is only a slit of aqueous then the angle is estimated to be dangerously narrow.

Gonioscopy

Gonio lenses permit observation of the anterior chamber angle by eliminating the cornea as a refracting surface. This is done by placing a concave surface against the cornea, thus allowing visualization of the angle using obliquely inclined mirrors.

2. Performing IOP check (Tonometry) before and after dilation to ensure patient’s IOP wasn’t affected. Carrying out Tonometry before dilation ensures the early detection of any possible glaucoma cases.

3.Have an appropriate Miotic available should dilation be too traumatic for the patient and the examiner has to constrict the pupil back.

4. Perform History Taking to rule out any allergies to any mydriatics or drugs, possible glaucoma cases.