COAST (COAST)

Study of low-energy laser treatment for ocular hypertension and open-angle glaucoma

Age
18 years or above
Gender
All
participants needed
790
Location
1
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Brief description of study

The goal of this study is to understand if SLT performed at low energy is as effective as SLT performed at standard energy, and also to see if repeating SLT at low energy once a year will prevent or delay the need for daily eye drop medications better than waiting for SLT to wear off before repeating it.

Eligibility of study

You may be eligible for this study if you meet the following criteria:

  • Conditions: Glaucoma and Ocular Hypertension
  • Age: 18 years or above
  • Gender: All

Inclusion Criteria:

  1. Age 18 or older and in good health
  2. Each eye with one of the following qualifying diagnoses (diagnoses may differ between eyes):
    1. High-risk ocular hypertension (OHT): IOP > 21 mmHg 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)
    2. Mild primary open-angle glaucoma: glaucomatous optic neuropathy, visual field mean deviation better than -6.0 dB with no points in the central 5° <15 dB (see figure on next page)
    3. Moderate primary open-angle glaucoma: glaucomatous optic neuropathy, visual field mean deviation equal to or worse than -6.0 dB but no worse than -12.0 dB and no central 5° points <15 dB or mean deviation -12.0 dB or better with 1 central 5° points <15 dB (see figure on next page).
  3. Each eye with BCVA 20/200 (UK 6/60) or better

Exclusion Criteria:

  1. Use of topical IOP-lowering medications for more than 6 cumulative months at any time in the past 5 years (this is a modification implemented during active enrollment)
  2. Any history of IOP-lowering laser (prophylactic iridotomy not included) or surgical procedure
  3. Advanced POAG in either eye (worse than moderate POAG as defined above)
  4. Glaucoma other than POAG (including pigmentary and pseudoexfoliation glaucoma) in either eye
  5. Mean IOP > 35 mmHg at either the screening or baseline visit in either eye
  6. Narrow or closed angle (Shaffer Grade 0, 1, or 2) in either eye
  7. Contraindications to SLT or any other study intervention
  8. Any corneal pathology that would preclude accurate assessment of IOP by Goldmann tonometry in either eye
  9. Any intraocular surgical procedure within the past 6 months in either eye
  10. Inability to attend all scheduled study visits
  11. Pregnant or planning to become pregnant in the next 4 years

The purpose of this research study is to learn whether a low-energy type of selective laser trabeculoplasty (SLT) works as well as standard-energy SLT in adults with high-risk ocular hypertension or mild to moderate primary open-angle glaucoma. The study will also learn whether repeating low-energy SLT once a year can prevent or delay the need for daily eye drop medicines better than waiting to repeat SLT until it wears off.

Participants will receive SLT at either low energy or standard energy. Some participants will have low-energy SLT repeated once a year, while others will wait to repeat SLT until the effect wears off. The study will compare these approaches based on how well they control eye pressure and whether people need to start daily eye drop medicines.

Who can participate:
Adults may be able to participate if they:

  • Are age 18 or older and in good health
  • Have high-risk ocular hypertension or mild to moderate primary open-angle glaucoma in each eye (the diagnosis can be different between eyes)
  • Have vision of 20/200 or better in each eye
  • Have not had pressure-lowering laser treatment or eye surgery before (prophylactic iridotomy does not count)
  • Have not used pressure-lowering eye drops for more than about 6 total months in the past 5 years

Updated on 01 Sep 2026. Study ID: 23-0529

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