Glaucoma surgery

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Glaucoma surgery

Glaucoma is a group of diseases affecting the optic nerve that results in vision loss and is frequently characterized by raised intraocular pressure (IOP). There are many glaucoma surgeries, and variations or combinations of those surgeries, that facilitate the escape of excess aqueous humor from the eye to lower intraocular pressure, and a few that lower IOP by decreasing the production of aqueous.

Procedures that facilitate outflow of aqueous humor[edit]

Laser trabeculoplasty[edit]

A trabeculoplasty is a modification of the trabecular meshwork. Laser trabeculoplasty (LTP) is the application of a laser beam to burn areas of the trabecular meshwork, located near the base of the iris, to increase fluid outflow. LTP is used in the treatment of various open-angle glaucomas.[1] The two types of laser trabeculoplasty are argon laser trabeculoplasty (ALT) and selective laser trabeculoplasty (SLT). As its name suggests, argon laser trabeculoplasty uses an argon laser to create tiny burns on the trabecular meshwork.[2] Selective laser trabeculoplasty is newer technology that uses a Nd:YAG laser to target specific cells within the trabecular meshwork and create less thermal damage than ALT.[3][4] SLT shows promise as a long term treatment.[5] In SLT a laser is used to selectively target the melanocytes in the trabecular meshwork. Though the mechanism by which SLT functions is not well understood, it has been shown in trials to be as effective as the older Argon Laser Trabeculoplasty. However, because SLT is performed using a much lower power laser, it does not appear to affect the structure of the trabecular meshwork (based on electron microscopy) to the same extent, so retreatment may be possible if the effects from the original treatment should begin wear off, although this has not been proven in clinical studies. ALT is repeatable to some extent with measurable results possible.


An iridotomy involves making puncture-like openings through the iris without the removal of iris tissue. Performed either with standard surgical instruments or a laser, it is typically used to decrease intraocular pressure in patients with angle-closure glaucoma. A laser peripheral iridotomy (LPI) is the application of a laser beam to selectively burn a hole through the iris near its base. LPI may be performed with either an argon laser or Nd:YAG laser.[6][7]

The benefits of glaucoma surgery with iridotomy versus no iridotomy are currently unclear. Preliminary data from two trials with a sample of 2502 eyes of 1251 participants showed evidence that iridotomy may increase angle width by 18 months (12.70 degrees), but may also be associated with IOP spikes at one hour after treatment.[8]


An iridectomy, also known as a corectomy or surgical iridectomy, involves the removal of a portion of iris tissue.[9][10] A basal iridectomy is the removal of iris tissue from the far periphery, near the iris root; a peripheral iridectomy is the removal of iris tissue at the periphery; and a sector iridectomy is the removal of a wedge-shaped section of iris that extends from the pupil margin to the iris root, leaving a keyhole-shaped pupil.

Filtering procedures: penetrating vs. non-penetrating[edit]

Filtering surgeries are the mainstay of surgical treatment to control intraocular pressure.[11] An anterior sclerotomy or sclerostomy is used to gain access to the inner layers of the eye[12][13] in order to create a drainage channel from the anterior chamber to the external surface of the eye under the conjunctiva, allowing aqueous to seep into a bleb from which it is slowly absorbed. Filtering procedures are typically divided into either penetrating or non-penetrating types depending upon whether an intraoperative entry into the anterior chamber occurs.[14][15]

Penetrating filtering surgeries are further subdivided into guarded filtering procedures, also known as protected, subscleral, or partial thickness filtering procedures (in which the surgeon sutures a scleral flap over the sclerostomy site[16]), and full thickness procedures.[17] Trabeculectomy is a guarded filtering procedure that removes of part of the trabecular meshwork.[18] [4] Full thickness procedures include sclerectomy, posterior lip sclerectomy (in which the surgeon completely excises the sclera on the area of the sclerostomy[16]), trephination, thermal sclerostomy (Scheie procedure), iridenclesis, and sclerostomy (including conventional sclerostomy and enzymatic sclerostomy).[15][19]

Non-penetrating filtering surgeries do not penetrate or enter the eye's anterior chamber.[20][21] There are two types of non-penetrating surgeries: Bleb-forming and viscocanalostomy.[22][23] Bleb forming procedures include ab externo trabeculectomy and deep sclerectomy.[23] Ab externo trabeculectomy (AET) involves cutting from outside the eye inward to reach Schlemm's canal, the trabecular meshwork, and the anterior chamber. Also known as non-penetrating trabeculectomy (NPT), it is an ab externo (from the outside), major ocular procedure in which Schlemm's canal is surgically exposed by making a large and very deep scleral flap. The inner wall of Schlemm's canal is stripped off after surgically exposing the canal . Deep sclerectomy, also known as nonpenetrating deep sclerectomy (PDS) or nonpenetrating trabeculectomy is a filtering surgery where the internal wall of Schlemm's canal is excised, allowing subconjunctival filtration without actually entering the anterior chamber;[24] in order to prevent wound adhesion after deep scleral excision and maintain good filtering results, it is sometimes performed with a variety of biocompatible spacers or devices, such as the Aquaflow collagen wick,[25] ologen Collagen Matrix,[26][27][28] or Xenoplast glaucoma implant.[29]

Viscocanalostomy is also an ab externo, major ocular procedure in which Schlemm's canal is surgically exposed by making a large and very deep scleral flap. In the VC procedure, Schlemm's canal is cannulated and viscoelastic substance injected (which dilates Schlemm's canal and the aqueous collector channels).

Surgical adjuvants Where wound modulation is needed to prevent closure of surgically created drainage channels, adjuvants such as the ologen collagen matrix implants may be used to facilitate healthy tissue regeneration. Scar formation at the site of excision or operation may block aqueous humor circulation, while healthy tissue regeneration will keep newly created drainage channels functional.[30][31][32][33]

Other surgical procedures[edit]

Goniotomy and trabeculotomy are similar simple and directed techniques of microsurgical dissection with mechanical disruption of the trabecular meshwork.[34][35] Goniotomy procedures include surgical goniotomy and laser goniotomy. A surgical goniotomy involves cutting the fibers of the trabecular meshwork to allow aqueous fluid to flow more freely from the eye.[36][37][38] Laser goniotomy is also known as goniophotoablation and laser trabecular ablation . In many patients suffering from congenital glaucoma, the cornea is not clear enough to visualize the anterior chamber angle. Although an endoscopic goniotomy, which employs an endoscope to view the anterior chamber angle, may be performed,[39] a trabeculotomy which accesses the angle from the exterior surface of the eye, thereby eliminating the need for a clear cornea, is usually preferred in these instances. A specially designed probe is used to tear through the trabecular meshwork to open it and allow fluid flow.[36][40]

Tube-shunt surgery or drainage implant surgery involves the placement of a tube or glaucoma valves to facilitate aqueous outflow from the anterior chamber.[36][41][42] Trabeculopuncture uses a Q switched Nd:YAG laser to punch small holes in the trabecular meshwork.[43][44] Goniocurretage is an "ab interno" (from the inside) procedure that used an instrument "to scrape pathologically altered trabecular meshwork off the scleral sulcus".[11] A surgical cyclodialysis is a rarely used procedure that aims to separate the ciliary body from the sclera to form a communication between the suprachoroidal space and the anterior chamber.[10] A cyclogoniotomy is a surgical procedure for producing a cyclodialysis, in which the ciliary body is cut from its attachment at the scleral spur under gonioscopic control.[10]

A ciliarotomy is a surgical division of the ciliary zone in the treatment of glaucoma.[10][45]


Canaloplasty is a nonpenetrating procedure utilizing microcatheter technology. To perform a canaloplasty, an incision is made into the eye to gain access to Schlemm's canal in a similar fashion to a viscocanalostomy. A microcatheter will circumnavigate the canal around the iris, enlarging the main drainage channel and its smaller collector channels through the injection of a sterile, gel-like material called viscoelastic. The catheter is then removed and a suture is placed within the canal and tightened. By opening the canal, the pressure inside the eye can then be relieved. Canaloplasty has two main advantages of over more traditional glaucoma surgeries. The first of these advantages is an improved safety profile over trabeculectomy. As canaloplasty does not require the creation of a bleb, significant long-term risks such as infection and hypotony (extremely low eye pressure) are avoided. The second main advantage is that when combined with cataract surgery, the IOP is reduced even further than when done alone.[46] Long term (three year) results have been published both in the US[46] and Europe[47] demonstrating a significant and sustained reduction in both eye pressure and the number of glaucoma medications required for glaucoma control.

Procedures that decrease production of aqueous humor[edit]

Cyclocryotherapy (frozen spot visible)

Certain cells within the eye's ciliary body produce aqueous humor. A ciliary destructive or cyclodestructive procedure is one that aims to destroy those cells in order to reduce intraocular pressure.[48]

Cyclocryotherapy, or cyclocryopexy, uses a freezing probe.[49] Cyclophotocoagulation, also known as transscleral cyclophotocoagulation, ciliary body ablation,[36] cyclophotoablation,[50] and cyclophototherapy,[35] uses a laser.[51][5] Cyclodiathermy uses heat generated from a high frequency alternating electric current passed through the tissue,[10] while cycloelectrolysis uses the chemical action caused by a direct current.[10]

A systematic review seeking to assess the safety and effectiveness of diode transscleral cyclophotocoagulation found one study in Ghana comparing patients who received low-energy versus high-energy variations of the procedure to treat glaucoma.[52] Overall, the review found that 47% of eyes treated with transscleral cytophotocoagulation saw an IOP decrease of at least 20%.[52] There were no differences between the low-energy and high-energy variations of the procedure in all reported outcomes, such as IOP control, and number of medications used after treatment.[52] Another Cochrane Systematic Review explored whether cyclodestructive procedures are better than other glaucoma treatments for the treatment of refractory glaucoma; however, the evidence was inconclusive.[53]

See also[edit]


  1. ^ "University of Michigan Health System - Surgery for Glaucoma". Archived from the original on 2006-09-04. Retrieved 2006-10-11.
  2. ^ " - Argon Laser Trabeculoplasty (ALT)". Archived from the original on 2006-11-11. Retrieved 2006-10-11.
  3. ^ "Review of Optometry - SLT: The Laser Picks Up Where Medications Leave Off". Archived from the original on 2006-10-17. Retrieved 2019-11-24.
  4. ^ Glaucoma Research Foundation - SLT: A New Type of Glaucoma Surgery
  5. ^ "Review of Ophthalmology: SLT for Glaucoma Threapy" Archived 2006-10-17 at the Wayback Machine Selective Laser Trabeculoplasty
  6. ^ Surgery Encyclopedia - Laser iridotomy
  7. ^ " - Laser Peripheral Iridotomy (PI)". Archived from the original on 2006-10-08. Retrieved 2006-10-11.
  8. ^ Le JT, Rouse B, Gazzard G (2018). "Iridotomy to slow progression of visual field loss in angle-closure glaucoma" (PDF). Cochrane Database Syst Rev. 2018 (6): CD012270. doi:10.1002/14651858.CD012270.pub2. PMC 6026549. PMID 29897635.
  9. ^ Surgery Encyclopedia - Iridectomy
  10. ^ a b c d e f Griffin, John W.; Cline, David; Hofstetter, Henry William (1997). Dictionary of Visual Science (4th ed.). Oxford: Butterworth-Heinemann. ISBN 0-7506-9895-0.
  11. ^ a b Jacobi PC, Dietlein TS, Krieglstein GK (April 1997). "Technique of goniocurettage: a potential treatment for advanced chronic open angle glaucoma". Br J Ophthalmol. 81 (4): 302–7. doi:10.1136/bjo.81.4.302. PMC 1722166. PMID 9215060.
  12. ^ "Search".
  13. ^ Berlin MS, Yoo PH, Ahn RJ (April 1995). "The role of laser sclerostomy in glaucoma surgery". Curr Opin Ophthalmol. 6 (2): 102–14. doi:10.1097/00055735-199504000-00016. PMID 10150851. S2CID 12008149.
  14. ^ "Archived copy". Archived from the original on 2014-07-27. Retrieved 2014-06-11.CS1 maint: archived copy as title (link)
  15. ^ a b "Archived copy". Archived from the original on 2011-08-21. Retrieved 2014-06-11.CS1 maint: archived copy as title (link)
  16. ^ a b [1]
  17. ^ "Glaucoma". 2007-11-12. Retrieved 2012-12-11.
  18. ^ Surgery Encyclopedia - Trabeculectomy
  19. ^ "Sclerostomy - procedure, recovery, test, blood, pain, complications, adults, time, infection, medication, types, risk, rate, Definition, Purpose, Demographics, Description". Retrieved 2012-12-11.
  20. ^ Hamard P, Lachkar Y (May 2002). "[Non penetrating filtering surgery, evolution and results]". J Fr Ophtalmol (in French). 25 (5): 527–36. PMID 12048520.
  21. ^ Lachkar Y, Hamard P (April 2002). "Nonpenetrating filtering surgery". Curr Opin Ophthalmol. 13 (2): 110–5. doi:10.1097/00055735-200204000-00010. PMID 11880725. S2CID 24144634.
  22. ^ "Archived copy". Archived from the original on 2014-07-14. Retrieved 2019-11-24.CS1 maint: archived copy as title (link)
  23. ^ a b "Archived copy" (PDF). Archived from the original (PDF) on 2014-07-14. Retrieved 2014-06-11.CS1 maint: archived copy as title (link)
  24. ^ Lachkar Y, Neverauskiene J, Jeanteur-Lunel MN, et al. (2004). "Nonpenetrating deep sclerectomy: a 6-year retrospective study". Eur J Ophthalmol. 14 (1): 26–36. doi:10.1177/112067210401400105. PMID 15005582. S2CID 36569523.
  25. ^ [2]
  26. ^ Aptel, F; Dumas S; Denis P (2009). "Ultrasound biomicroscopy and optical coherence tomography imaging of filtering blebs after deep sclerectomy with new collagen implant". Eur J Ophthalmol. 19 (2): 223–30. doi:10.1177/112067210901900208. PMID 19253238. S2CID 22594085.
  27. ^ Tanuj, D; Amit S; Saptorshi M; Meenakshi G (May 2013). "Combined Subconjunctival and Subscleral Ologen Implant Insertion In Trabeculectomy". Eye. 27 (7): 889. doi:10.1038/eye.2013.76. PMC 3709396. PMID 23640614.
  28. ^ Matthew, SJ; Sarkisian S; Nathan B; James MR. "Initial experience using a collagen matrix implant (ologen) as a wound modulator with canaloplasty: 12 month results". 2012 ARVO Congress, Ft. Lauderdale. Retrieved 12 December 2020.
  29. ^ Anisimova SY, Anisimova SI, Larionov EV. "Biological drainage – Xenoplast in glaucoma surgery (experimental and 10-year of clinical follow-up)" (PDF). 2012 EGS Congress, Copenhagen. Retrieved 12 December 2020.
  30. ^ Dada T, Sharma R, Sinha G, Angmo D, Temkar S (2016). "Cyclodialysis-enhanced trabeculectomy with triple Ologen implantation". Eur J Ophthalmol. 26 (1): 95–7. doi:10.5301/ejo.5000633. PMID 26044372. S2CID 83593.CS1 maint: multiple names: authors list (link)
  31. ^ Min JK, Kee CW, Sohn SW, Lee HJ, Woo JM, Yim JH (2013). "Surgical outcome of mitomycin C-soaked collagen matrix implant in trabeculectomy". J Glaucoma. 22 (6): 456–62. doi:10.1097/IJG.0b013e31826ab6b1. PMID 23263152. S2CID 20615016.CS1 maint: multiple names: authors list (link)
  32. ^ Tanuj D, Amit S, Saptorshi M, Meenakshi G (2013). "Combined subconjunctival and subscleral ologen implant insertion in trabeculectomy". Eye (Lond). 27 (7): 889. doi:10.1038/eye.2013.76. PMC 3709396. PMID 23640614.CS1 maint: multiple names: authors list (link)
  33. ^ Aptel F, Dumas S, Denis P (2009). "Ultrasound biomicroscopy and optical coherence tomography imaging of filtering blebs after deep sclerectomy with new collagen implant". Eur J Ophthalmol. 19 (2): 223–30. doi:10.1177/112067210901900208. PMID 19253238. S2CID 22594085.CS1 maint: multiple names: authors list (link)
  34. ^ Glaucoma, Primary Congenital at eMedicine
  35. ^ a b Aniridia in the Newborn at eMedicine
  36. ^ a b c d Primary Congenital Glaucoma
  37. ^ "Glaucoma Surgery | Glaucoma Research Foundation". 2012-08-20. Retrieved 2012-12-11.
  38. ^ Surgery Encyclopedia - Goniotomy
  39. ^ Joos KM, Shen JH, Ren Q (1994). Parel JA, Ren Q (eds.). "Endoscopic goniotomy probe for holmium:YAG laser delivery". Proc. SPIE. Ophthalmic Technologies IV. 2126: 259. Bibcode:1994SPIE.2126..259J. doi:10.1117/12.178563. S2CID 135831690.[permanent dead link]
  40. ^ "Video". Archived from the original on 2006-09-22. Retrieved 2006-10-11.
  41. ^ Surgery Encyclopedia - Tube-shunt surgery
  42. ^ Haddrill, Marilyn. "Glaucoma Surgery -". Archived from the original on 2008-04-24. Retrieved 2012-12-11.
  43. ^ Epstein DL, Melamed S, Puliafto CA, Steinert RF (July 1985). "Neodymium: YAG laser trabeculopuncture in open-angle glaucoma". Ophthalmology. 92 (7): 931–7. doi:10.1016/S0161-6420(85)33932-5. PMID 4022580.
  44. ^ van der Zypen E, Fankhauser F (1979). "The ultrastructural features of laser trabeculopuncture and cyclodialysis. Problems related to successful treatment of chronic simple glaucoma". Ophthalmologica. 179 (4): 189–200. doi:10.1159/000308894. PMID 121373.
  45. ^ "" (PDF). Retrieved 2012-12-11.
  46. ^ a b Lewis, Richard A.; Kurt von Wolff; Manfred Tetz; Norbert Koerber; John R. Kearney; Bradford J. Shingleton; Thomas W. Samuelson (April 2011). "Canaloplasty: Three-year results of circumferential viscodilation and tensioning of Schlemm canal using a microcatheter to treat open-angle glaucoma". Journal of Cataract and Refractive Surgery. 37 (4): 682–690. doi:10.1016/j.jcrs.2010.10.055. PMID 21420593. S2CID 26495012.
  47. ^ Bull, Holger; Kurt von Wolf; Norbert Körber; Manfred Tetz (October 2011). "Three-year canaloplas ty outcomes for the treatment of open-an gle glaucom a: European study results". Graefes Arch Clin Exp Ophthalmol. 249 (10): 1537–45. doi:10.1007/s00417-011-1728-3. PMID 21732110. S2CID 22142101.
  48. ^ [3] Archived April 9, 2015, at the Wayback Machine
  49. ^ "Archived copy". Archived from the original on 2006-09-25. Retrieved 2006-10-11.CS1 maint: archived copy as title (link)
  50. ^ Hamel P, Levin A (December 2003). "Glaucoma Surgical Techniques in Children: From Past to Future (Part 1 of 2)". Techniques in Ophthalmology. 1 (4): 227–34. doi:10.1097/00145756-200312000-00007.
  51. ^ " - Cyclophotocoagulation". Archived from the original on 2006-11-11. Retrieved 2006-10-11.
  52. ^ a b c Michelessi M, Bicket AK, Lindsley K (2018). "Cyclodestructive procedures for non-refractory glaucoma". Cochrane Database Syst Rev. 2018 (4): CD009313. doi:10.1002/14651858.CD009313.pub2. PMC 6277057. PMID 29694684.
  53. ^ Chen MF, Kim CH, Coleman AL (2019). "Cyclodestructive procedures for refractory glaucoma". Cochrane Database Syst Rev. 10 (3): CD012223. doi:10.1002/14651858.CD012223.pub2. PMC 6409080. PMID 30852841.CS1 maint: multiple names: authors list (link)