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Characteristically Unilateral Glaucomas

Differential Diagnosis

Joel S. Schuman, MD, FACS; Malik Y. Kahook, MD; Rachel L. Anderson, MD; and David L. Epstein, MD, MMM

Certain kinds of glaucomas are typically unilateral, whereas other kinds regularly affect both eyes. This chapter is intended to provide a synopsis for the differential diagnosis of certain unilateral glaucomas, most of which are described individually in greater detail elsewhere in this book.

In this chapter, we will provide an outline of unilateral glaucomas that belong to the following general categories:

• Unilateral angle-closure glaucomas
  
• Unilateral peripheral synechial glaucomas
  
• Unilateral secondary open-angle glaucomas

For this synopsis, unilateral angle-closure glaucomas are defined as those glaucomas in which there is axial shallowing of the anterior chamber and ballooning forward of the periphery of the iris to close the angle. Peripheral synechial glaucomas are defined for this discussion as those glaucomas in which there is no axial shallowing or pupillary block to explain the development of peripheral synechiae, but peripheral anterior synechiae are present. The term secondary open-angle glaucomas is self-explanatory.

UNILATERAL ANGLE-CLOSURE GLAUCOMAS

In primary acute angle-closure glaucoma, a closed angle and elevated intraocular pressure (IOP) in only one eye are very common. In the subacute and chronic forms of primary angle closure, unilateral glaucoma is less common. When one finds angle closure and elevated IOP in one eye, in most cases, the angle in the fellow eye is narrow and predisposed to closure. Occasionally, the angle in the fellow eye appears of good width, and one might conclude that it would not close, but this is generally an erroneous conclusion, particularly if the iris is convex. In several cases, despite knowledge of spontaneous closure of the angle in the first eye, at our initial gonioscopic examination, we estimated that the angle in the fellow eye was of safe width and have been chagrined to find that it subsequently closed. One may be misled in a single gonioscopic examination by a transient deepening of the anterior chamber and widening of the angle due to the action of agents, such as aqueous humor suppressants or hypertonic agents, given systemically for treatment of the contralateral glaucomatous eye.

The cases that one can tell with some assurance that the angle in the fellow eye will not close are those in which there is considerable anatomical asymmetry, such as when one eye is hypermetropic and the other is myopic, or when the cornea is smaller in the affected eye than in the fellow uninvolved eye, and the configuration of the anterior segment is quite different in the 2 eyes.

True unilateral angle-closure glaucoma can be produced by the following:

• Dislocation of the lens
  
• Hypermature swollen lens
  
• Intraocular tumor
  
• Central retinal vein occlusion
  
• Panretinal photocoagulation
  
• Choroidal hemorrhage
  
• Massive vitreous hemorrhage
  
• Scleral buckling surgery
  
• Orbital venous congestion
  
• Retrobulbar tumor
  
• Iris bombé from inflammation
  
• Iris bombé from epithelialization
  
• Pupillary block or malignant glaucoma in aphakia or pseudophakia
  
• Persistent primary hyperplastic vitreous in childhood
  
• Congenital ectropion uveae