SLT Laser for Glaucoma: Equipment, Procedure and Selection

What SLT is and where it fits

Selective laser trabeculoplasty, or SLT, applies short laser pulses to the trabecular meshwork, the drainage tissue of the eye, with the aim of improving fluid outflow and lowering intraocular pressure. It is one of several options in glaucoma management, alongside medication and surgery. Whether SLT is appropriate for a patient is a decision for the treating ophthalmologist, and this page gives no treatment advice.

The word selective refers to the way the laser energy is delivered: very short pulses at a wavelength absorbed by pigmented cells in the meshwork, so that surrounding tissue is not heated in the same way as with older continuous-wave lasers. Technical details of the underlying concept are given in the manufacturer literature, and clinics should rely on their clinicians' training for protocol.

What type of laser is used for SLT

SLT lasers are Q-switched, frequency-doubled Nd:YAG lasers emitting at 532 nm, a green wavelength. The A.R.C. Laser CITO 532 is such a system designed for the anterior segment. Instead of a flash lamp, it uses diode-pumped µ-Chip technology: no high voltage in the system, power deviation below 2% per the manufacturer, a homogeneous spot and fast pulse sequences.

Key technical data for CITO 532: wavelength 532 nm, pulse energy 0.2 to 2.0 mJ, a spot size of 400 µm, and Laser Class 3B. A large 7-inch touchscreen keeps the selected treatment energy in view, Quick-Repetition (about 10 Hz) shortens treatment time, and slit illumination, laser and observation optics are coaxial. A permanent physician protection filter is built in. For a comparison with the other common ophthalmic laser, see SLT versus YAG laser.

• 532 nm Q-switched, frequency-doubled Nd:YAG
• Diode-pumped µ-Chip, no flash lamp
• Pulse energy 0.2 to 2.0 mJ, spot size 400 µm
• Quick-Repetition about 10 Hz
• Permanent physician protection filter

The SLT procedure and possible side effects in general terms

SLT is typically performed in an outpatient setting at a slit lamp. After topical anaesthetic, a contact lens is used to view the angle and apply pulses. Settings are chosen by the physician; our article on SLT laser settings discusses parameters from an equipment perspective only.

Questions on SLT laser side effects belong with the treating clinician. In general, patients may experience short-term effects such as mild inflammation or a temporary change in eye pressure, and follow-up is arranged accordingly. Clinics should have written protocols for pressure checks, post-treatment care and escalation.

Equipping a glaucoma clinic for SLT

A glaucoma service needs more than the laser: a slit lamp platform, a gonioscopy lens, a tonometer, visual field testing, imaging and a trained team. If the clinic also does capsulotomy or iridotomy, the COBRA combines two independent lasers in one unit: the CITO 532 for SLT and the Q-Las Nd:YAG for capsulotomy and iridotomy. Its two-column table adjusts electronically up to 920 mm and is wheelchair-accessible.

Compare the user interface, treatment-time features, optics, ergonomics and training. Also consider other glaucoma laser options such as diode laser cyclophotocoagulation. Safety rules for the room are in our medical laser safety guide.

Supply and support in the UAE

Beckfinity supplies the CITO 532 and the COBRA from A.R.C. Laser in the UAE. Contact our specialists to discuss a configuration for your glaucoma service, including training, installation and service, and confirm registration requirements with DHA, DOH or MOHAP.