If medications do not control eye pressure, or if they create intolerable side effects, surgery may be necessary in a small percentage of people with glaucoma. The standard procedures are usually one of the following:
The Procedure. Filtration surgery has been used for more than 100 years with only minor modifications. It uses conventional surgical techniques known as full-thickness filtering surgery or guarded filtering surgery (trabeculectomy).
The procedure has a high success rate. About 50% of patients no longer need medication after surgery. Thirty-five to 40% of those who still need medication have better control of their glaucoma.
A newer instrument called a trabectome has allowed for a less invasive type of trabulectomy surgery. The trabectome procedure appears to be a safe and simple way to lower eye pressure. It can be performed before a traditional trabulectomy, if needed.
Side Effects. Many of the serious side effects or complications that occur with filtration surgery involve blebs (blister-like bumps).
Supportive Medication for Preventing Scarring. Specific drugs, usually mitomycin C, are often used in conjunction with the procedure to prevent scarring and closure. A large review of studies of mitomycin C supported its effectiveness in increasing surgical success in nearly all patients. Fluorouracil (5-FU) appears to be similar in effectiveness but has a high risk for complications and is not used as often as in the past.
The Procedure. Laser trabeculoplasty involves the following steps:
Laser surgery is not a cure. Patients still need to take anti-glaucoma eye drop medications every day. Within 2 - 5 years, about half of patients need either additional surgery or new medications.
Complications. In about 35% of patients, pressure increases after surgery. In most cases it is temporary, but in rare cases the increased pressure is permanent and vision loss can occur. Use of the drug apraclonidine (Iopidine) or pilocarpine can help prevent this elevated pressure. About a third of patients also develop adhesive-like substances called peripheral anterior synechiae that cause the iris to stick to part of the cornea.
Drainage implants, also known as tube shunts, may be used to drain fluid in certain cases, such as if glaucoma is not responsive to any standard procedure or is caused by certain conditions.
Candidates. Drainage implants may be useful in the following conditions:
The Procedure. In general, the procedure involves:
Complications. Complications include:
The implant often becomes blocked, and additional surgery may be needed.
Deep sclerectomy and viscocanalostomy are less invasive techniques than filtering surgery that leave the anterior chamber (front of the eye) intact and avoid creation of blebs.
In both deep sclerectomy and viscocanalostomy, the surgeon creates a flap in the outer part of the sclera (the white part of the eye) and then removes a deep piece of the sclera underneath.
Many variations are under investigation. In general, the procedures have fewer complications afterward than standard filtering surgery, although they require excellent surgical skill. Nonpenetrating techniques do not lower IOPs as much as conventional surgery does, however.
Cataracts and Glaucoma. For patients with both glaucoma and cataracts, doctors recommend:
Some evidence indicates that the combined approach generally offers better control over eye pressure for patients with both cataracts and glaucoma. However, it is still unclear which specific type of surgical procedure works best. [For more information, see In-Depth Report #26: Cataracts.]
Diode laser transscleral cyclophotocoagulation (TSCPC), also called laser cycloablation, reduces aqueous production by destroying the muscles that control the lens for near and far vision (the ciliary body). There is a chance of vision loss with this procedure, so it is generally reserved for people with end-stage glaucoma or those who fail to benefit from any other therapies.
For an acute closed-angle glaucoma attack, emergency microsurgery is usually necessary after reducing pressure with medications.
Iridotomy or Iridectomy. Either laser (iridotomy) or conventional (iridectomy) surgery may be used. With either procedure an ophthalmologist makes a tiny opening in the iris to let the aqueous humor flow out more freely. Because acute glaucoma commonly occurs later in the other eye, surgeons will often recommend surgery in the unaffected eye to prevent a second attack.
Laser iridotomy almost never requires hospitalization, and postsurgical treatment includes only aspirin and eye drops. It has almost completely replaced conventional surgery, which requires anesthesia and hospitalization.
Vision will be blurred, and recovery can take 4 - 8 weeks. Following surgery, patients can usually safely use previously restricted anticholinergic medications, such as antihistamines and certain antidepressants.
Phacoemulsification and Intraocular Lens Implantation. Phacoemulsification and intraocular lens implantation, a procedure ordinarily used for cataracts, may prove to be beneficial for some patients with acute angle-closure glaucoma requiring surgery. [For more information, see In-Depth Report #26: Cataracts.]
Aptel F, Cucherat M, Denis P. Efficacy and tolerability of prostaglandin analogs: a meta-analysis of randomized controlled clinical trials. J Glaucoma. 2008 Dec;17(8):667-73.
Burr JM, Mowatt G, Hernández R, Siddiqui MA, Cook J, Lourenco T, et al. The clinical effectiveness and cost-effectiveness of screening for open angle glaucoma: a systematic review and economic evaluation. Health Technol Assess. 2007 Oct;11(41):iii-iv, ix-x, 1-190.
Chang R, Budenz DL. New developments in optical coherence tomography for glaucoma. Curr Opin Ophthalmol. 2008 Mar;19(2):127-35.
Cheng JW, Wei RL, Cai JP, Li Y. Efficacy and tolerability of nonpenetrating filtering surgery with and without implant in treatment of open angle glaucoma: a quantitative evaluation of the evidence. J Glaucoma. 2009 Mar;18(3):233-7.
Dueker DK, Singh K, Lin SC, Fechtner RD, Minckler DS, Samples JR, et al. Corneal thickness measurement in the management of primary open-angle glaucoma: a report by the American Academy of Ophthalmology. Ophthalmology. 2007 Sep;114(9):1779-87.
Gedde SJ, Schiffman JC, Feuer WJ, Herndon LW, Brandt JD, Budenz DL. Treatment outcomes in the tube versus trabeculectomy study after one year of follow-up. Am J Ophthalmol. 2007 Jan;143(1):9-22.
Hatt S, Wormald R, Burr J. Screening for prevention of optic nerve damage due to chronic open angle glaucoma. Cochrane Database Syst Rev. 2006 Oct 18;(4):CD006129.
Hernández R, Rabindranath K, Fraser C, Vale L, Blanco AA, Burr JM; OAG Screening Project Group. Screening for open angle glaucoma: systematic review of cost-effectiveness studies. J Glaucoma. 2008 Apr-May;17(3):159-68.
Higginbotham EJ. Managing glaucoma during pregnancy. JAMA. 2006 Sep 13;296(10):1284-5.
Hodge WG, Lachaine J, Steffensen I, Murray C, Barnes D, Foerster V, et al. The efficacy and harm of prostaglandin analogues for IOP reduction in glaucoma patients compared to dorzolamide and brimonidine: a systematic review. Br J Ophthalmol. 2008 Jan;92(1):7-12.
Kwon YH, Fingert JH, Kuehn MH, Alward WL. Primary open-angle glaucoma. N Engl J Med. 2009 Mar 12;360(11):1113-24.
Lam DS, Tham CC, Lai JS, Leung DY. Current approaches to the management of acute primary angle closure. Curr Opin Ophthalmol. 2007 Mar;18(2):146-51.
Lemij HG, Reus NJ. New developments in scanning laser polarimetry for glaucoma. Curr Opin Ophthalmol. 2008 Mar;19(2):136-40.
Leske MC, Heijl A, Hyman L, Bengtsson B, Dong L, Yang Z; EMGT Group. Predictors of long-term progression in the early manifest glaucoma trial. Ophthalmology. 2007 Nov;114(11):1965-72. Epub 2007 Jul 12.
Rivera JL, Bell NP, Feldman RM. Risk factors for primary open angle glaucoma progression: what we know and what we need to know. Curr Opin Ophthalmol. 2008 Mar;19(2):102-6.
Rolim de Moura C, Paranhos A Jr, Wormald R. Laser trabeculoplasty for open angle glaucoma. Cochrane Database Syst Rev. 2007 Oct 17;(4):CD003919.
Rosenberg EA, Sperazza LC. The visually impaired patient. Am Fam Physician. 2008 May 15;77(10):1431-6.
Stewart WC, Konstas AG, Nelson LA, Kruft B. Meta-analysis of 24-hour intraocular pressure studies evaluating the efficacy of glaucoma medicines. Ophthalmology. 2008 Jul;115(7):1117-1122.e1. Epub 2008 Feb 20.
Vass C, Hirn C, Sycha T, Findl O, Bauer P, Schmetterer L. Medical interventions for primary open angle glaucoma and ocular hypertension. Cochrane Database Syst Rev. 2007 Oct 17;(4):CD003167.
Wishart MS, Dagres E. Seven-year follow-up of combined cataract extraction and viscocanalostomy. J Cataract Refract Surg. 2006 Dec;32(12):2043-9.
© 2011 University of Maryland Medical Center (UMMC). All rights reserved.
UMMC is a member of the University of Maryland Medical System,
22 S. Greene Street, Baltimore, MD 21201. TDD: 1-800-735-2258 or 1.866.408.6885