Direct Selective Laser Trabeculoplasty in a Ethnic Chinese Population

The objective of this study is to evaluate the safety and effectiveness of Direct Selective Laser Trabeculoplasty (DSLT) at various energy settings in ethnic Chinese participants with POAG or OHT.

Geffen et al investigated the safety \& effectiveness of performing trans-scleral/limbal SLT without the use of a gonioscopic lens. They were able to show that this technique was as efficacious as conventional SLT, taking less time as well as causing fewer complications due to its non-contact methodology and with the laser beam not passing diagonally through the cornea. The study comprised of 14 control subjects, and 14 treated subjects; all with primary open-angle glaucoma. The controls were treated using traditional SLT for 360 degrees, using a goniolens to direct the laser beams. The treatment group received the same laser treatment, but this was administered directly to the peri-limbal area. Success (a decrease of ≥15% at 6 months with no additional medications, laser, or glaucoma surgery) was achieved in 12 (85.7%) study patients and 9 (69.2%) controls (p = 0.385). Complications were mild and transient in both groups, although significantly more common within the control group (p\< 0.0001).

First-in Human open-label, prospective study was performed in Sheba Medical Center, Israel (cliniclatrials.gov NCT01383525, accepted for publication) with the aim to assess safety and efficacy of the EAGLE system on IOP reduction in POAG patients (manuscript submitted for publication). 15 subjects were enrolled and treated. The results show good safety profile and an IOP reduction of 18.1%, 21.4%, 18.8% at 1, 3 and 6 months follow- up visits respectively. The number of medications was also reduced. 14 subjects were medicated at baseline with an average of 1.6±1.0 medications per subject. At 6 months, only 3 subjects were medicated with an average of 0.4±0.9 medications per subject.

A European multicenter randomized controlled masked study, the GLAUrious trial, was initiated in October 2018. The objective of this study is to demonstrate the non-inferiority of the novel DSLT compared to SLT. 192 subjects were enrolled. No ocular SAE were reported up to date in the DSLT arm (cliniclatrials.gov NCT03750201) and results of the trial are expected in a few months.

SLT is an approved treatment option available to OAG patients that can be used with or without hypotensive lowering medication to reduce IOP. The safety and effectiveness of SLT has been demonstrated. , , , Due to its IOP lowering effect, this treatment may result in a decrease in the number of or elimination in the need for hypotensive lowering medications. Inflammatory reactions following SLT include cystoid macular edema and anterior chamber inflammation (more common). , , The inflammation is usually mild to moderate in its severity and transient, with reductions in intensity seen within 24 hours post-treatment, and resolution seen in most eyes within 5 days. Another risk associated with laser trabeculoplasty treatment is the incidence of post-operative IOP spikes. These usually occur in the immediate post-operative phase (1-2 hours) and careful patient selection and prophylactic treatment can be used to avoid their occurrence.

DSLT is performed directly, and preliminary studies have demonstrated that it is a shorter and simpler technique when compared to SLT4. Further, it has been suggested that it could be more easily administered in those patients where contact techniques prove problematic or where anatomical obstacles exist, such as in those patients with narrow iridocorneal angles or those with prominent facial bones.4 This same study demonstrated similar IOP lowering effectiveness between DSLT and SLT. Furthermore, it revealed that DSLT resulted in less corneal injury, less inflammation and less post-operative discomfort when compared to standard SLT.

Accordingly, risks of inclusion in the study are those associated with the SLT procedure. Preliminary studies suggest that treatment with DSLT is comparable to SLT. Benefits of DSLT include a speedier treatment, less post-operative inflammation, and less subjective discomfort. In addition, this simple automatic procedure does not require use of a goniolens and therefore has the potential to increase the accessibility of glaucoma care throughout the world.

This clinical trial is a non-randomized, multi-center, prospective study. As the Eagle system was not tested before in ethnic Chinese population. The objective of this study is to evaluate the safety and effectiveness of Direct Selective Laser Trabeculoplasty (DSLT) at various energy settings in ethnic Chinese participants with POAG or OHT.

Eligibility Criteria:
Inclusion Criteria:

* Patients must meet the following inclusion criteria in the study eye to be eligible:

  1. Age 21 years or older, any gender, of Chinese Han ethnicity, with corrected visual acuity \> 6/18 in both eyes
  2. Diagnosed with:

     1. Mild to moderate primary open angle glaucoma\* (that is, excluding exfoliative or pigmentary glaucoma), or
     2. Ocular hypertension without glaucomatous optic neuropathy (excavation, diffuse or focal thinning or notching of the neuroretinal rim, visible nerve fiber layer defects, or asymmetry of the vertical cup-to-disc ratio of \>0.2 between eyes) and with normal visual field
  3. At screening IOP ≤30 mmHg and on 0-1 topical hypotensive medication with a stable medication regiment for two months prior to screening.
  4. At baseline, unmedicated IOP ≥ 22mmHg to ≤30mmHg
  5. Gonioscopically visible scleral spur for 360 degrees without indentation
  6. Ability to visualize the peri-limbal sclera for 360 degrees using a lid speculum
  7. Willing and able to participate in the 12-month study, to comply with the study procedures and to adhere to the follow-up schedule
  8. Patients capable of giving informed consent

Exclusion Criteria:

* Individuals with the following characteristics should be excluded from the study (unless specified otherwise, all ocular criteria refer to the study eye only):

  1. Angle Closure Glaucoma
  2. Congenital or developmental glaucoma
  3. Secondary glaucoma, including exfoliative or pigmentary glaucoma
  4. Presence of any Peripheral Anterior Synechiae (PAS) in the study eye
  5. Inability to provide a reliable visual field test (defined as fixation losses, false positives or false negatives greater than 33%)
  6. Advanced, late or severe glaucoma, as defined by the AGS guidelines
  7. A visual field MD of worse than -12dB in either eye
  8. Cup:Disc Ratio of more than 0.8
  9. More than 1 hypotensive medications required (combination drops are considered as 2 medications)
  10. Using oral hypotensive medication treatment for IOP control
  11. Use of beta blockers in the fellow eye. Also, beta blockers may not be administered to the fellow eye during the 12 month follow-up period due to its known cross-over effect.
  12. Washout of ocular hypotensive medication would present a significant risk to the participant.
  13. Prior incisional or laser glaucoma surgery (including previous SLT or LPI) in the study eye.
  14. Prior corneal refractive surgery in the study eye
  15. Cataract surgery ≤ 12 months prior to enrollment
  16. Presence of visually significant cataract that in the opinion of the investigator should be operated within the next 12 months
  17. Clinically significant disease in either eye as determined by the Investigator
  18. Dense pigmentation affecting more than 2 hours of the perilimbal area
  19. Pterygium present in the peri-limbal target treatment area
  20. Women who are pregnant or may become pregnant during the course of the study
  21. In the opinion of the investigator the patient might require other ocular surgery within the 12-month follow-up period, unless for further reduction of their IOP
  22. Concurrent treatment with topical, nasal, inhaled or systemic steroids
  23. Uncontrolled systemic disease that could impact the ability of the patient to attend follow up visits, in the opinion of the investigator
  24. Participation in another interventional clinical study in the last 30 days prior to the screening visit
  25. Participant with professions that are dependent on their vision, such as pilot or commercial driver