Adaptive Optics OCT Evaluation of Rhopressa's Effects on the Retinal Ganglion Cells in Glaucoma Patients

October 26, 2026 updated by: Brett King

The purpose of this study is to compare how two FDA-approved eye drops: netarsudil (Rhopressa) and timolol, protect nerve cells in the eye of adults with open-angle glaucoma. Both medications lower pressure inside the eye, but researchers want to learn if Rhopressa is more effective at slowing down or preventing the loss of retinal ganglion cells. These cells are essential for sight because they carry visual signals from the eye to the brain.

Participants in this study will complete a total of 6 study visits over 12 months:

  • Participants will spend 6 months using Rhopressa eye drops and 6 months using Timolol eye drops. The order of the two eye drops will be chosen randomly.
  • At scheduled study visits, researchers will examine participants' eyes and measure eye pressure.
  • Researchers will take detailed pictures of the back of the eye using a specialized high-resolution camera called adaptive optics optical coherence tomography (AO-OCT).
  • Participants will also complete specialized visual field testing to measure eye function.

Researchers will count and track individual nerve cells over time to determine if one medication offers better protection against cell loss than the other.

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Detailed Description

Glaucoma is a chronic, progressive optic neuropathy characterized by functional and structural alterations, specifically the degeneration and loss of retinal ganglion cells (RGCs). Currently, the main modifiable factor for intervention is aimed at lowering intraocular pressure (IOP). While IOP reduction slows disease progression, it does not halt neurodegeneration. Rho kinase (ROCK) inhibitors have been reported to provide benefit in neurodegenerative diseases. Netarsudil ophthalmic solution (Rhopressa) is a ROCK inhibitor approved for the treatment and management of open-angle glaucoma that lowers IOP and has reported protective effects on neural tissue. However, previous attempts to illustrate true cell loss or protection using clinical instrumentation have not demonstrated an effect to date.

High-resolution retinal imaging based on adaptive optics optical coherence tomography (AO-OCT) enables direct visualization, tracking, and quantification of individual ganglion cell layer (GCL) somas in the living human eye. Leveraging the unique imaging capabilities and extraordinary sensitivity of ultra-high-speed AO-OCT, this study will test the hypothesis that treatment with netarsudil is more effective at reducing glaucomatous ganglion cell loss while producing comparable intraocular pressure reduction to that of the comparator.

This prospective, randomized, investigator-masked, cross-over pilot study will compare RGC survival rates between two treatment groups (Rhopressa and Timolol). Thirteen subjects with open-angle glaucoma will be recruited. Following a screening assessment and medication washout period based on drug class, eligible subjects are randomized 1:1 into two age-matched cohorts:

  • Cohort 1: Receives Rhopressa (one drop once at night) for 6 months, then crosses over to receive Timolol 0.25% (one drop twice a day) for 6 months.
  • Cohort 2: Receives Timolol 0.25% (one drop twice a day) for 6 months, then crosses over to receive Rhopressa (one drop once at night) for 6 months.

At Visit 2 (baseline), Visit 4 (6 months), and Visit 6 (12 months), subjects undergo imaging using the Indiana AO-OCT system along with Goldmann applanation tonometry, standard clinical OCT, and OCT-guided microperimetry (MP-3). AO-OCT imaging is performed at the same retinal regions surrounding arcuate defects to enable longitudinal cellular-level analysis. Primary and secondary endpoints evaluate differences in the rate of change of RGC soma density, individual RGC counts, and GCL thickness between treatment periods.

Study Type

Interventional

Enrollment (Estimated)

13

Phase

  • Phase 4

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

  • Name: Brett J King, OD, FAAO, Dipl AAO (Glaucoma)
  • Phone Number: (812) 855-1344
  • Email: kingbrj@iu.edu

Study Contact Backup

  • Name: Kaitlyn M Asher, CCRC, BS
  • Phone Number: 2194067487
  • Email: kamasher@iu.edu

Study Locations

  • United States
    • Indiana
      • Bloomington, Indiana, United States, 47405
        • Recruiting
        • Indiana University School Of Optometry
        • Contact:
          • Kaitlyn M Asher, CCRC, BS
          • Phone Number: 2194067487
          • Email: kamasher@iu.edu
        • Contact:
          • Brett J King, OD, FAAO, Dipl AAO(Glaucoma)
          • Phone Number: (812) 855-1344
          • Email: kingbrj@iu.edu
        • Sub-Investigator:
          • Donald T Miller, PhD
        • Sub-Investigator:
          • Matthew Keller, OD

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

18 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Description

Inclusion Criteria:

  • All subjects will be 18 years of age or older
  • Subjects must be diagnosed with open-angle glaucoma and have had an eye exam within the past year
  • Subjects with glaucoma will have structural (optic nerve and retinal nerve fiber layer) and functional (visual field testing) defects consistent with the diagnosis of glaucoma
  • Subjects will have a corrected acuity of 20/50 or better and be able to fixate
  • Naïve to medication subjects or post washout IOP between 18 and 34 mmHg
  • Spherical equivalent from +3 diopters to -6 diopters, with a cylinder of <-3 diopters
  • Subject is willing and able to comply with the protocol requirements and to remain in the study for its full duration, including all scheduled visits and follow-up assessments

Exclusion Criteria:

  • Subjects with a known intolerance to netarsudil ophthalmic solution
  • Subjects with a known intolerance to, or contraindication for, timolol maleate
  • Any subject whom the investigator determines to be at unacceptable risk for the washout or believes is unlikely to complete the study
  • Subjects with retinal disease or optic neuropathies other than glaucoma that, in the opinion of the investigator, could confound the study assessments or outcome
  • Female subjects who are pregnant, breastfeeding, or of childbearing age who are not sterile or using an acceptable method of contraception during the study

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Other
  • Allocation: Randomized
  • Interventional Model: Crossover Assignment
  • Masking: Double

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Rhopressa first, then Timolol

Participants will instill netarsudil 0.02% (Rhopressa) ophthalmic solution (1 drop in the study eye once daily in the evening) for the first 6 months (Months 0-6). At the Month 6 visit, participants will cross over to instill timolol maleate 0.25% ophthalmic solution (1 drop in the study eye twice daily) for the remaining 6 months (Months 6-12).
Drug: Netarsudil 0.02% Ophthalmic Solution [RHOPRESSA]

Netarsudil ophthalmic solution (Rhopressa) is an FDA-approved Rho kinase inhibitor indicated for the treatment of ocular hypertension and open-angle glaucoma. In this study, participants will instill 1 drop of netarsudil 0.02% ophthalmic solution in the study eye once daily in the evening for 6 months.

Other Names:
  • Rhopressa
Drug: Timolol Maleate 0.25% Ophthalmic Solution

Timolol maleate ophthalmic solution is an FDA-approved non-selective beta-adrenergic receptor blocking agent indicated for the treatment of ocular hypertension and open-angle glaucoma. In this study, participants will instill 1 drop of timolol maleate 0.25% ophthalmic solution in the study eye twice daily (in the morning and evening) for 6 months.

Other Names:
  • Timoptic
Experimental: Timolol first, then Rhopressa

Participants will instill timolol maleate 0.25% ophthalmic solution (1 drop in the study eye twice daily) for the first 6 months (Months 0-6). At the Month 6 visit, participants will cross over to instill netarsudil 0.02% (Rhopressa) ophthalmic solution (1 drop in the study eye once daily in the evening) for the remaining 6 months (Months 6-12).
Drug: Netarsudil 0.02% Ophthalmic Solution [RHOPRESSA]

Netarsudil ophthalmic solution (Rhopressa) is an FDA-approved Rho kinase inhibitor indicated for the treatment of ocular hypertension and open-angle glaucoma. In this study, participants will instill 1 drop of netarsudil 0.02% ophthalmic solution in the study eye once daily in the evening for 6 months.

Other Names:
  • Rhopressa
Drug: Timolol Maleate 0.25% Ophthalmic Solution

Timolol maleate ophthalmic solution is an FDA-approved non-selective beta-adrenergic receptor blocking agent indicated for the treatment of ocular hypertension and open-angle glaucoma. In this study, participants will instill 1 drop of timolol maleate 0.25% ophthalmic solution in the study eye twice daily (in the morning and evening) for 6 months.

Other Names:
  • Timoptic

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Change in GC soma density (cells/mm²)
Time Frame: Baseline, 6 months, and 12 months

Change in ganglion cell (GC) soma density during treatment with timolol versus netarsudil (Rhopressa)
Baseline, 6 months, and 12 months

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Changes in GC soma counts (number of cells)
Time Frame: Baseline, 6 months, and 12 months

Changes in ganglion cell (GC) soma counts during treatment with timolol versus netarsudil (Rhopressa)
Baseline, 6 months, and 12 months
Changes in GCL thickness (micrometers (µm))
Time Frame: Baseline, 6 months, and 12 months

Changes in ganglion cell layer (GCL) thickness during treatment with timolol versus netarsudil (Rhopressa)
Baseline, 6 months, and 12 months

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Brett King

Collaborators

Alcon Research

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

October 1, 2026

Primary Completion (Estimated)

January 1, 2028

Study Completion (Estimated)

January 1, 2028

Study Registration Dates

First Submitted

September 22, 2026

First Submitted That Met QC Criteria

September 22, 2026

First Posted (Actual)

September 29, 2026

Study Record Updates

Last Update Posted (Actual)

October 28, 2026

Last Update Submitted That Met QC Criteria

October 26, 2026

Last Verified

October 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 32936
  • 17426-BJKing (Other Identifier: Sterling IRB)

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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