Tip of the Month
Publishing date: July 2015
The science behind the tip
Transient visual disturbance after trabeculectomy is common and it can take several months for the vision to recover. (1) The risk of permanent visual loss with modern techniques is a rare consequence of the surgery (2).
In patients with advanced visual field loss, especially if there is a "split" fixation (loss of visual field within the central 5°), the surgery can be followed by permanent loss of vision as a consequence of unexplained "wipe out" in 1-2% and by severe hypotony maculopathy in a further 1.5% (1) (3). Risk factors include high preoperative IOP and severe hypotony on the first post operative day (3) (4). It is more likely to occur when the surgery is complicated (4).
Because of the medico-legal implications, patients with advanced glaucoma should be warned of the risk before they undergo trabeculectomy. This should be documented on the consent form.
Contributor: J F Salmon MD, Oxford UK
1. Francis BA, Hong B, Winarko J et al. Visual loss and recovery after trabeculectomy: risk and associated risk factors. Arch Ophthamol 2011; 129:1011-7.
2. Balekudaru S, George R, Panday M et al. Prospective evaluation of early visual loss following glaucoma-filtration surgery in eyes with split fixation. J Glaucoma 2014; 23: 211-8
3. Costa VP, Smith M, Spaeth GL. Loss of visual acuity after trabeculectomy. Ophthalmology 1993; 100: 599-612.
4. Law SK, Nguyen AM, Coleman AL et al. Severe loss of central vision in patients with advanced glaucoma undergoing trabeculectomy. Arch Ophthalmol 2007; 125: 1044-50.
Tip Reviewer: Roger Hitchings
Tip Editors: John Salmon and Gordana Sunaric Mégevand