Optimal Treatment Protocol for Selective Laser Trabeculoplasty - Repeat Trial (OSLT-R)

Glaucoma is a common eye disease that can lead to blindness. The only known way to reduce the rate of disease progression is by reducing the pressure in the eye (the intraocular pressure, IOP). Selective laser trabeculoplasty (SLT) is an ophthalmic laser intervention with the purpose of reducing the IOP. SLT can be performed in different ways, with four of the treatment protocols being evaluated in the Optimal SLT (OSLT) trial. SLT is a repeatable procedure, but scientific evidence is scarce regarding more than one repetition. In this trial, patients included in the OSLT trial will be invited to the extended trial (OSLT-R), for further follow-up and re-treatment with SLT, if needed.

Subjects already included in the OSLT trial (NCT03798223) will be invited to the extended trial (OSLT-R) when OSLT follow up is scheduled to terminate. Patients are re-treated as needed, according to the randomized group assignment performed in the OSLT inclusion process. Each patient is followed until the last of: 3 years after OSLT inclusion 31 December 2024 or Six months after the last SLT was performed, during the above time period. The OSLT-R trial is aiming to elucidate: If the SLT efficacy, in terms of relative IOP reduction (percent of baseline IOP), changes with additional SLT iterations. If the longevity of IOP reduction after SLT changes with additional SLT iterations. If repeated SLT is associated with a change in the frequency and severity of postoperative discomfort or adverse events. All of the above will be analyzed within each of the four treatment groups (SLT protocols) in the trial. Further, analysis will also be conducted regarding differences between the treatment groups regarding the above. Further, analysis will be performed regarding SLT efficacy depending of the total number of SLT:s an eye has received, including those performed before entering the OSLT and OSLT-R trials.

The treatment protocol is masked for the patient and for the nurses and optometrists conducting measurement of intraocular pressure during follow-up.

SLT treatment in either half of the trabecular meshwork (180 degrees) consisting of 50+/-5 adjacent laser effects. The energy is adjusted 0,1 mJ below the threshold of formation of micro bubbles.

SLT treatment in either half of the trabecular meshwork (180 degrees) consisting of 50+/-5 adjacent laser effects. The energy is adjusted to achieve the formation of micro bubbles at 50-75% of laser effects.

SLT treatment in the full circumference of the trabecular meshwork (360 degrees) consisting of 100+/-10 adjacent laser effects. The energy is adjusted 0,1 mJ below the threshold of formation of micro bubbles.

SLT treatment in the full circumference of the trabecular meshwork (360 degrees) consisting of 100+/-10 adjacent laser effects. The energy is adjusted to achieve the formation of micro bubbles at 50-75% of laser effects.

A drop of Pilocarpine 4% is administered to the eye 20 minutes before SLT. Immediately before SLT a drop of Tetracaine hydrochloride 1% is administered. Selective laser trabeculoplasty is conducted through a Latina lens, in a fashion determined by randomization to a study arm (see description).

Relative IOP reduction for each SLT iteration is calculated as the percentage IOP reduction from baseline (the mean of 3 pre-SLT measurements) to result IOP (the mean of the IOP at follow-up 1, 3 and 6 months after SLT).

Kaplan-Meier survival analysis will be conducted, measuring the proportion of eyes that stay in the study groups but do not receive any further IOP-lowering intervention, including repeat SLT.

From randomization to failure (IOP lowering intervention, except repeat SLT) or censoring (death, patients choice), assessed until the last of: 1. 3 years after randomization; 2. 31 Dec 2024 or; 3. Six months after the last SLT during that timespan.

Kaplan-Meier survival analysis will be conducted, measuring the proportion of eyes that stay in the study groups but do not receive any further IOP-lowering intervention, except repeat SLT.

From each SLT iteration to failure (IOP lowering intervention incl. repeat SLT) or censoring (death, patients choice), assessed until the last of: 1. 3 years after randomization; 2. 31 Dec 2024 or; 3. Six months after the last SLT during that timespan.

The proportion of eyes achieving and maintaining an IOP reduction of at least 20% compared to baseline.

From randomization until the last of: 1. 3 years after randomization; 2. 31 Dec 2024 or; 3. Six months after the last SLT during that timespan.

Absolute IOP reduction for each SLT iteration is calculated as the IOP reduction, in mmHg, from baseline (the mean of 3 pre-SLT measurements) to result IOP (the mean of the IOP at follow-up 1, 3 and 6 months after SLT).

The patient will grade perioperative pain on an arbitrary scale between 0 (no pain) and 4 (maximum pain) on a written protocol.

The patient will grade post-operative pain on an arbitrary scale between 0 (no pain) and 4 (maximum pain) on a written protocol, also stating the duration of pain.

The patient will grade post-operative sensitivity to light on an arbitrary scale between 0 (no difference) and 4 (very intense sensitivity to light) on a written protocol, also stating the duration of light sensitivity.

The patient will grade post-operative impairment of vision on an arbitrary scale between 0 (no difference) and 4 (cannot see ones own hand) on a written protocol, also stating the duration of vision impairment.

The patient will grade post-operative redness of the eye on an arbitrary scale between 0 (no difference) and 4 (very intense redness) on a written protocol, also stating the duration of redness.

From randomization until the last of: 1. 3 years after randomization; 2. 31 Dec 2024 or; 3. Six months after the last SLT during that timespan. However, generally adverse events are anticipated to emerge in the first post-operative days or weeks.

Inclusion Criteria: Included in the OSLT trial Followed up without the need for other treatment escalation than repeat SLT Exclusion Criteria: Unable to participate in follow up due to health conditions, strength or physical location.