Pigmentary Glaucoma Clinical Presentation

Updated: Oct 23, 2018
  • Author: Jim C Wang (王崇安), MD; Chief Editor: Hampton Roy, Sr, MD  more...
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Presentation

History

Patients with pigment dispersion syndrome (PDS) and pigmentary glaucoma (PG) are usually asymptomatic. Many, particularly myopes, are identified on routine eye examination. Some individuals may describe episodes of haloes and/or blurred vision associated with exercise or dark exposure (resulting from acute pigment release and temporary IOP rise).

Previous history of ocular trauma, surgeries, glaucoma, or other eye diseases that may result in abnormal pigmentation of the anterior segment structures should be noted. Some patients with subtle manifestations may have been previously diagnosed with ocular hypertension, juvenile-onset glaucoma, or primary open-angle glaucoma. Sulcus placement of intraocular lens may infrequently produce anterior chamber pigmentation similar to PDS and pigmentary glaucoma.

Family history of glaucoma or other eye conditions should also be inquired in detail.

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Physical Examination

Detailed and careful slit-lamp examination is critical to early recognition of PDS and pigmentary glaucoma. Diagnostic signs are usually bilateral and symmetric. However, on occasion, the abnormalities may be very asymmetric. The most prominent clinical findings are discussed below.

Pigment deposits on the posterior surface of the cornea

The pigment is typically densest near the corneal center and forms a characteristic shape (Krukenberg spindle) that corresponds to aqueous fluid convection currents. Krukenberg spindle generally appears as a central, vertical, brown band up to 6 mm long and 3 mm wide. It tends to be slightly decentered inferiorly and wider at its base than its apex. The amount of pigment present can be quite variable. Visual acuity is usually unaffected, as patients with PDS and pigmentary glaucoma do not appear to have thicker corneas or decreased endothelial cell counts. [11] With time, the corneal pigment becomes smaller and lighter and often requires careful examination for identification. 

Krukenberg spindle. Krukenberg spindle.
Pigment on posterior surface of cornea. Pigment on posterior surface of cornea.

Mid-peripheral iris transillumination defects

Transillumination defects appear in a radial spokelike configuration in the mid-peripheral iris and are most prominent inferiorly or inferonasally. This finding is pathognomonic for PDS and pigmentary glaucoma. Contact of the posteriorly bowed concave iris with anterior lens zonules is likely responsible for this characteristic iris transillumination pattern. Searching for iris transillumination defects prior to pupillary dilation using a small slit beam in a darkened room is best. Iris transillumination defects are present in 90% of patients with pigment dispersion. Transillumination defects may be absent in eyes with thick dark irides.

Characteristic iris transillumination defects. Characteristic iris transillumination defects.

Dense trabecular meshwork pigmentation

Gonioscopy should be performed prior to pupillary dilation. The anterior chamber angle is typically wide open with a homogeneous, darkly pigmented trabecular meshwork band. Excess pigment deposits may also be noted on the Schwalbe line. In some older patients, trabecular meshwork hyperpigmentation can regress. This produces a pattern of lighter trabecular meshwork pigment band in the inferior versus superior angle. This is called the pigment reversal sign and may be the only evidence to suggest pigment dispersion.

Trabecular meshwork hyperpigmentation. Trabecular meshwork hyperpigmentation.

Pigment accumulation can also be seen on the anterior surface of the iris (as concentric rings within the iris furrows or causing diffuse darkening of iris color), on the anterior lens surface, along the zonules, and between the posterior lens capsule and anterior hyaloid.

Pigment accumulation on anterior surface of iris. Pigment accumulation on anterior surface of iris.
Pigment deposits on anterior lens surface. Pigment deposits on anterior lens surface.
Pigment accumulation on posterior lens zonules. Pigment accumulation on posterior lens zonules.

Patients with PDS and pigmentary glaucoma have an increased risk of retinal detachment (6%-7%). Retinal breaks and lattice degeneration also occur twice as frequently in these eyes than in age- and refraction-matched controls. Detailed fundus examination and prophylactic treatment of these retinal lesions may be indicated.

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Diagnosis

PDS is diagnosed based on the clinical triad of pigment deposit on corneal endothelium, mid-peripheral iris transillumination defects, and heavy pigmentation of the trabecular meshwork. The presence of all three findings in the absence of another cause (ie, ocular trauma or sulcus posterior chamber intraocular lens [PCIOL]) confirms this condition. The unique mid-peripheral iris transillumination defects are so pathognomonic for pigment dispersion that its lone presence is sufficient for making a presumptive diagnosis of PDS or pigmentary glaucoma. In eyes with corneal and/or trabecular meshwork pigment accumulation but without the characteristic iris transillumination defects, no formal diagnostic criteria have been established. Disease is likely present when accompanied by other consistent findings (ie, elevated IOP, zonular or posterior capsule pigment).

Pigment dispersion can occur with normal or elevated IOP. [11] IOP is usually higher in pigmentary glaucoma than in PDS. Pigmentary glaucoma is diagnosed when signs of PDS are accompanied by optic nerve cupping and/or visual field loss.

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