Transvitreal endocyclophotocoagulation

Abstract

Transvitreal endophotocoagulation of the ciliary processes is a little-used option for eyes with refractory glaucoma. No histopathologic studies of animals or humans have described its effects. We sought to characterize this cilioablative procedure in an animal model, examine its effects in human eyes histopathologically, and evaluate its clinical safety and efficacy in a large series of patients with long-term follow-up.ANIMAL MODEL: Rabbit eyes were treated with lensectomy, vitrectomy, and transvitreal photocoagulation of the ciliary processes. Eyes were enucleated immediately after surgery and at weekly intervals up to 1 month. Light and electron microscopic evaluation of histopathologic changes was performed. Human Eyes: The pathology laboratory files were searched for cases with a history of endocyclophotocoagulation prior to enucleation, and three eyes were identified. Histopathologic sections were retrieved and examined. Clinical Series: A retrospective clinical review was performed of a single surgeon's experience with endolaser to the ciliary processes, including all cases with adequate data on ocular history, preoperative and postoperative visual acuity, intraocular pressure (IOP), and glaucoma medications, and details of surgery. Only eyes with at least 6 months' follow-up were included.ANIMAL MODEL: Histopathologic examination of rabbit eyes treated with endocyclophotocoagulation demonstrated acute changes of ciliary process destruction, proteinaceous exudate, stromal edema, nuclear pyknosis, and pigment dispersion. Vascular congestion was seen with some hemorrhage. Later, replacement by fibrous or fibrovascular scar developed with loss of the pigmented and nonpigmented ciliary epithelia, absence of ciliary architectural elements, and pigment rounding and clumping. Human Eyes: Histopathologic examination of enucleated human eyes revealed total ablation of the ciliary processes with fibrosis and pigment clumping in areas of treatment. Abrupt transitions between treated and untreated regions could be identified. In some areas fibrocellular membrane proliferation was found extending over the scars that replaced the ciliary processes. Clinical series: Seventy-three patients were identified ranging in age from 2 to 85 years (mean, 57.7), with follow-up of 6 to 130 months (mean, 28.6). Mean number of previous operations was 3.5; mean number of previous glaucoma operations was 1.3. Preoperative mean IOP was 38 mmHg (range, 19 to 75), postoperative mean IOP was 16 mmHg (range, 1 to 50). At 6 months, 58 of 72 eyes (81%) with available IOP data had IOP greater than 5 mmHg and less than 22. At 12 months 48 of 55 (87.3%) were successfully controlled by these criteria, and at last follow-up 50 of 73 (68%). Fifty-six of 73 eyes (77%) were considered clinically stable at the last follow-up in terms of visual acuity, anatomic integrity, and IOP < or = 23 off all glaucoma medications. Visual acuity was stable or improved in 53 of 73 eyes (73%). Complications developed in 9 eyes (12%), including IOP < or = 6 mmHg in 6 eyes (8.2%), peripheral choroidal effusion in 4 (5.5%), fibrinous anterior chamber reaction in 3 (4.1%), phthisis in 2 (2.7%), and choroidal hemorrhage in 1. Thirty-five eyes had penetrating keratoplasty performed before or at the same time as endolaser (an average of 2.14 grafts each), Graft rejection occurred in 4 eyes (11%), and long-term failure of grafts occurred in 11 of 35 (31%). In 31 eyes, additional surgical procedures were performed at the time of endocyclophotocoagulation.Endocyclophotocoagulation successfully ablates the ciliary processes, which are replaced with fibrous scar. Surgical results compare favorably with other methods of glaucoma therapy in complicated eyes in terms of IOP control, visual preservation, and complication rate. Endolaser to the ciliary body was especially successful in glaucomatous eyes after keratoplasty, although corneal graft prognosis