peripheral iris. An argon or diode laser is used with an Abraham contact lens or gonioscopy lens and the following laser parameters: spot diameter 200–500 mm, power 200–400 mW, and a duration of 0.2–0.5 s. For 3601 treatment, the ideal number of applications per quadrant is 5–6 (total: 20–30 distributed along the circumference); each should be separated by a distance equal to twice the spot diameter, and visible vessels should be avoided. Confluence of the photocoagulative lesions produces ischemic zones in the iris, secondary atrophy, and widening of the angle.

Topical steroids are administered for the first 4–7 postoperative days. The patient is reexamined 24 h, 1 week and 3–4 weeks after treatment to evaluate efficacy and check for complications.

Complications

The most common complications are mild, transient iritis associated with an increase in the IOP; endothelial lesions (especially in patients with nanophthalmus); anterior angle and posterior iridolenticular synechiae; and permanent mydriasis (rare).

Efficacy

Peripheral iridoplasty is an effective and relatively safe treatment provided that is not performed with high-energy levels. A single treatment is sufficient to open the angular recess in 85–90% of patients with the plateau iris syndrome followed for 10 years (Ritch et al., 2004). A recent randomized controlled trial demonstrated the efficacy of this approach in cases of acute angle-closure glaucoma compared with conventional systemic pressurereducing drug therapy (Lam et al., 2002).

LASER cyclophotocoagulation

Introduction

The use of methods aimed at diminishing IOP by destroying the ciliary body and thus reducing aqueous-humor production dates back to the 1930s. Weve (1933) and Vogt (1936) proposed

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diathermy and penetrating diathermy, respectively, for the electrocoagulative destruction of the ciliary body in patients with glaucoma.

Cyclodiathermy, which was associated with a high complication rate and poor results, was eventually abandoned in favor of cyclocryotherapy. The latter technique was introduced by Bietti (1950) and it was regarded as the cyclodestructive procedure of choice for over 30 years.

The mechanism by which cyclocryotherapy destroys the ciliary process involves the formation of intracellular calcium crystals, which is associated with ischemic necrosis of the epithelium and stromal components of the ciliary body (Wilkes and Fraunfelder, 1979). The standard method calls for application of the cryoprobe to the conjunctiva with the anterior border approximately 22 mm from the limbus. The temperature is reduced (between 701C and 901C), and four to eight applications are made per quadrant (depending on operator preferences). Because of the high rate of complications associated with this approach (pressure spikes, hypotonia, marked inflammatory reactions, intense pain, hemophthalmus, cataract, phthisis bulbi), cyclocryotherapy has also be gradually abandoned.

Beckman et al. (1972) proposed the use of a ruby laser (694 nm) for transscleral cyclophotocoagulation of the ciliary bodies, but in the past decade, cyclocryocoagulation has gradually been abandoned in favor of cyclophotocoagulation performed with an Nd:YAG (1064 nm) laser, which guarantees good results with moderate complications.

The most widely used techniques are transscleral contact and noncontact photocoagulation and transpupillary photocoagulation.

Indications and contraindications

Cyclophotocoagulation procedures have traditionally been reserved for patients whose glaucoma is refractory to medical and surgical treatment, those with neovascular glaucoma, blindness and eye pain due to increased IOP, and cases of advanced or end-stage glaucoma (Pastor et al., 2001). In effect, this approach has been considered the treatment of last resort. In recent years, however, some