Transscleral cyclophotocoagulation (TSCPC), laser ablation of the ciliary processes, can reduce production of aqueous and lower intraocular pressure (IOP) in eyes with uncontrolled glaucoma. 1-3 Due to associated risks such as severe inflammation, cycloablative procedures are traditionally reserved for advanced glaucoma, after the patient has been unresponsive to other therapies. However, with modified treatment parameters, TSCPC can induce significantly less inflammation and postoperative pain than cryotherapy or other transscleral procedures, making it a reasonable treatment option in conjunction with cataract surgery.
TSCPC is an in-office procedure requiring no incision and no antibiotics. Patients do not have to lie down or rest after surgery, and the risk of hypotony is low. Additionally, applying less energy over a longer treatment time, a technique called slow coagulation, can reduce the related risk of inflammation and allow the surgeon to employ TSCPC earlier in the treatment paradigm.
In earlier treatment parameters for TSCPC, an 810-nm diode laser was used to apply power at 2 W for 2-second intervals. Modified guidelines for slow coagulation (Figure 1) now indicate setting the power to 1 W and administering 4-second laser applications around the circumference of the eye. The G-Probe glaucoma device (Iridex) is designed so that when it is positioned at the limbus (Figure 2), the laser pulses are delivered 1.2 mm posterior to the edge, directly above the ciliary body. A typical treatment, approximately 300° around the limbus, requires 20 to 25 individual laser applications. For a video of TSCPC, visit eyetube.net/?v=virig.
Applying less energy over a longer period allows the laser pulses to penetrate the ciliary epithelium and shrink the ciliary processes and epithelial cells that produce the aqueous fluid. This is achieved without burning collateral tissues or causing mini explosions within the eye, thus producing less inflammation.
Any inflammation that occurs should be treated aggressively. I suggest following TSCPC with a drop of prednisolone acetate 1% or difluprednate and atropine 1% and prescribing steroid eye drops four to six times per day and one cycloplegic drop two to four times per day. The latter can be discontinued if the patient has no discomfort from ciliary spasm, and steroid drops should be tapered slowly. Patients often remain on topical steroids for at least 4 weeks to prevent macular edema and reduce inflammation.
COMBINING TSCPC WITH CATARACT SURGERY
Glaucoma and cataract are often concomitant, and surgeons should therefore consider how treatments for the two diseases can work together. TSCPC is repeatable and can be performed before or after cataract surgery. In patients with uncontrolled or higher IOP or in those with a dense cataract, applying TSCPC before opening the eye for cataract surgery allows the surgeon to control IOP and reduce the risk of suprachoroidal hemorrhage. In postcataract surgery patients, TSCPC can be a good alternative to glaucoma treatments that create a hole in the eye, especially when the surgeon is concerned that IOP may drop too quickly.
A 65-year-old black man with neovascular glaucoma had previously undergone trabeculectomy and placement of an Ahmed glaucoma valve. At this presentation, IOP in his left eye was in the upper 40s mm Hg despite a hypotensive medication regimen including a betablocker, a carbonic anhydrase inhibitor, and an alphaagonist. Although his neovascular disease was quiet, chronic angle-closure glaucoma and cataract formation in his left eye were noted. His vision was 20/200 in the affected eye.
Due to the failure of previous surgeries and ongoing ocular hypotensive medications to lower IOP, TSCPC combined with cataract surgery was proposed as the best surgical option to control his glaucoma.
Surgery was performed under retrobulbar block. Trypan blue dye was injected to stain the capsule for better visualization during capsulorrhexis. Because the complex cataract was the more technically difficult part of the procedure, I performed cataract surgery first, without complication, and the retrobulbar block was then maintained during TSCPC to eliminate any discomfort from the laser. I applied 20 applications over 300° of the limbus, with lower power and longer duration as described above.
One day after surgery, the patient reported no excessive pain. Inflammation was moderate, with +2 cells in the anterior chamber. IOP decreased to 15 mm Hg in the operated eye, and visual acuity improved to 20/30. I prescribed steroids and antibiotics for 1 month, and since this time the patient’s IOP in the operated eye remains in the upper teens.
I commonly use TSCPC to lower IOP in eyes with severe glaucoma. Switching to parameters for slow coagulation has reduced the associated inflammation and has thus allowed me to use the treatment in earlier stages of glaucoma. Aggressive initial treatment of any resulting inflammation is recommended, whether TSCPC is performed before, after, or in conjunction with cataract surgery.
Robert J. Noecker, MD, MBA, practices at Ophthalmic Consultants of Connecticut in Fairfield. Dr. Noecker states that he has no financial interest in the products or companies mentioned. He may be reached at tel: +1 203 366 8000; e-mail: email@example.com.
- Lai JS, Tham CC, Chan JC, et al. Diode laser transscleral cyclophotocoagulation as primary surgical treatment for medically uncontrolled chronic angle closure glaucoma: long-term clinical outcomes. J Glaucoma. 2005;14:14-19.
- Noureddin BN, Zein W, Haddad C, et al. Diode laser transscleral cyclophotocoagulation for refractory glaucoma: a 1 year follow-up of patients treated using an aggressive protocol. Eye. 2006;20:329-335.
- Grueb M, Rohrbach JM, Bartz-Schmidt KU, et al. Transscleral diode laser cyclophotocoagulation as primary and secondary surgical treatment in primary open-angle and pseudoexfoliative glaucoma: long-term clinical outcomes. Graefes Arch Clin Exp Ophthalmol. 2006;244:1293-1299.