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Endoscopic cyclophotocoagulation (ECP) was introduced as an alternative to trans-scleral cyclophotocoagulation for treating refractory glaucomas in order to minimise complications such as phthisis and hypotony by providing direct visualisation of the ciliary processes.
Glaucoma following penetrating keratoplasty, which has an incidence ranging from 10–52%, often proves refractory to medical treatment.1–3 We introduce a case of refractory post-PKP glaucoma in order to demonstrate the efficacy of ECP in treating post-PKP glaucoma and to describe its potential delayed effect in achieving intraocular pressure control .
A 50 year old African-American man, who had undergone previous cataract surgery, anterior vitrectomy, and anterior chamber intraocular lens placement in his left eye in 1987, presented with pseudophakic bullous keratopathy and hand movement vision in his left eye. In April of 2000, the patient underwent a penetrating keratoplasty in which an 8 mm donor graft was placed in a 7.5 mm host site. Two weeks following the procedure, the patient developed elevated intraocular pressure in the 45–50 mm Hg range which was refractory to both medical therapy and discontinuation of topical steroids. An Ahmed valve was placed in June of 2000, yet his intraocular pressure eventually returned to the preoperative range despite the addition of four topical glaucoma medications (timolol 0.5%, brimonidine 0.2%, dorzolamide 2.0%, and latanoprost 0.005%).
In April of 2001, the patient underwent treatment with endoscopic cyclophotocoagulation via a limbal approach as described by Chen et al.4 The patient received 300 degrees of treatment at settings ranging from 20–50 mW of energy with laser applied for 0.5–2 seconds until ciliary process whitening and contraction was observed (Fig 1).
During the first postoperative week, the patient was treated with topical polymyxin B/trimethoprim drops four times a day, and hyoscine (scopolamine) 0.25% drops three times a day. He was also treated with topical prednisolone acetate 1% four times per day, and was tapered off by the third postoperative week. Despite being restarted on all four of his glaucoma medications within 2 weeks of the procedure, the patient continued to have poorly controlled intraocular pressure in the 30–45 mm Hg range which persisted for more than 3 months. However, 14 weeks after the cyclodestructive procedure, the intraocular pressure suddenly began to decrease without any further surgical intervention. The patient’s intraocular pressure has remained well controlled in the 10–15 mm Hg range for more than 1 year following ECP, and the total number of glaucoma drugs has been systematically reduced from four to two. Furthermore, the patient has not developed any signs of hypotony, phthisis, or graft failure.
Previous studies have demonstrated significant pressure lowering within 2–4 weeks of endoscopic cyclophotocoagulation.4,5 This represents the first reported case of late success with ECP, with intraocular pressure control achieved more than 3 months following ECP. Though both topical corticosteroids and cycloplegics may lead to a rise in intraocular pressure, the pressure remained elevated more than 2 months after discontinuing both types of medications.6,7
Reports vary regarding the number of degrees of treatment necessary to achieve effective results with endoscopic cyclophotocoagulation.4,5 However, success is ultimately dependent on the extent of treatment along the anteroposterior axis of the ciliary processes as well as the size of the treatment zone.4 The delayed response observed in this case likely represents incomplete treatment with late fibrotic changes in the ciliary processes, as signs of hypotony and phthisis remain absent.8
A high incidence of both acute (35–41%) and chronic (23–29%) graft failure has been associated with drainage tube implants in the treatment of post-PKP glaucoma.9,10 In contrast, no cases of irreversible graft failure were observed in 16 post-PKP patients treated with ECP, with only a single patient (6%) developing acute graft rejection.4 We describe this case in order to demonstrate that the effects of ECP may be appreciated on the order of several months following treatment, and to illustrate, as shown previously, that ECP can often be used safely and effectively in treating refractory post-PKP glaucoma.