Pigment dispersion syndrome
 

Radial transillumination of the iris in the midperiphery region. This is seen with retroillumination. Each transillumination represents area devoid of pigment epithelium Krukenberg's spindle with diffuse illumination Krukenberg's spindle  with retroillumination

The corneal endothelium contains vertically orientated deposition of pigments (Krukenberg's spindle). The pigment may also be seen on the iris and the lens (and also the trabecular meshwork but in the clinical  examination you are unlikely to be asked to perform gonioscopy on the patient). Retroillumination shows  mid-periphery iris transillumination. In the examination: look for any peripheral iridoctomies which may be performed in an attempt to reduce the production of pigment look at the patient's glasses, most of this patients has myopia mention you like to examine the optic disc for cupping

Questions:

1. What proportion of patients with pigment dispersion syndrome develop glaucoma?

Answer
About 1/3

2. Is it possible for a patient with pigment dispersion syndrome to develop glaucomatous disc changes despite a normal intraocular pressure and if so why?

Answer
Patients with pigment dispersion syndrome typically shows wide fluctuation of the intraocular pressures. The pressure may be normal in the clinic but can rise precipitously following exercise or pupillary dilatation in the dark.
 

3. What is the cause of the Krukenberg's spindle?

Answer
In pigment dispersion syndrome, the iris is bowed posteriorly causing it to rub against the lens zonule. This results in the loss of the pigment epithelium and hence the transillumination and the endothelium deposition of pigment. The vertical orientation of the pigment is due to conventional current.

4. What is the theoretical advantage of peripheral iridotomies in pigment dispersion syndrome?

Answer
It equalizes the pressures between the posterior and anterior chamber and therefore corrects the posterior bowing of the iris. This reduces the rubbing and thus decreased pigment loss.
 
 

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