My personal way to estimate whether a patient is at risk for wipeout following glaucoma surgery, is to perform a confrontation visual field with a red-topped bottle

This should be done monocularly with the bottle moved from the area of scotoma towards fixation. One must ensure that the patient is constantly looking at the examiner’s eye and understands that he/she should tell you the first instant the red top is seen. If the patient is not able to see the top when it crosses the visual axis from the area of non-seeing then fixation is lost. The moving test is repeated in other quadrants.

There are various attributed reasons for “snuff out’ or “wipe out” after surgery, including a marked post-operative pressure rise or fall. However, the cases in which this occurs are most often those in whom field loss has, prior to pressure lowering, extended into fixation. Where this is the case both the operative strategy and the postoperative care need to be modified appropriately.

Contributor: George L. Spaeth, Philadelphia, US

References:

Kolker A.E. Visual prognosis in advanced glaucoma: a comparison of medical and surgical therapy for retention of vision in 101 eyes with advanced glaucoma. Trans Am Ophthalmol Soc. 1977;75:539–555. Costa V.P., Smith M., Spaeth G.L. Loss of visual acuity after trabeculectomy. Ophthalmology. 1993;100:599–612

Tip Reviewer: Roger Hitchings
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