Glaucoma gonioscopy

For closed-angle glaucoma, the presence of a narrow angle is usually visualized by gonioscopy. IOP is generally markedly elevated (e.g., 40 to 90 mm Hg) when symptoms are present. Additional signs include hyperemic conjunctiva, cloudy cornea, shallow anterior chamber, and occasionally edematous and hyperemic optic disk. 

Gonioscopy Because pupil dilation may precipitate an acute attack of narrow-angle glaucoma, evaluate anterior chamber angle by gonioscopy prior to beginning therapy. 

Gonioscopy is important for every patient with glaucoma (unless contraindicated). 

Coleman AL, Yu E, Evans SJ. Use of gonioscopy in Medicare beneficiaries before glaucoma surgery. J Glaucoma 2006 15 486-493. 

Hoskins HD. Interpretive gonioscopy in glaucoma. Invest Ophthalmol Vis Sci 1972 11 997-1102. 

The angle of the eye is examined by gonioscopy, which requires the use of special lenses. Gonioscopy is performed to rule out angle-closure or secondary causes of lOP elevation, such as angle recession, pigmentary glaucoma, and exfoliation syndrome. The peripheral contour of the iris is examined for plateau iris, and the trabecular meshwork for peripheral anterior synechiae, as well as for neovascular or inflammatory membranes. 

Eyes with potential angle closure require a miotic drug and should not be treated with beta-blockers alone. To exclude the risk of precipitating glaucoma in a susceptible individual, gonioscopy is recommended before starting topical beta-adrenoceptor antagonist therapy. 

It is a potent surface anaesthetic mainly used in ophthalmology and induces no initial irritation. Beeause of its rapid onset of aetion it is useful for most occular procedures that require topical anaesthesia such as tonometry, removal of foreign particles, gonioscopy and various short operative procedures which may involve the conjunctiva and cornea. It has also been reported to be employed frequently as a surface anaesthesia in glaucoma surgery and in cataract operations. 

---