A Phase 4 interventional study of Netarsudil 0.02% Ophthalmic Solution [RHOPRESSA] and Timolol Maleate 0.25% Ophthalmic Solution in Open Angle Glaucoma (OAG) and Glaucoma, sponsored by Brett King. Recruiting at 1 site in United States. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-09-29.
Sponsored by Brett King · Phase 4, Interventional, and Other
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:
Researchers will count and track individual nerve cells over time to determine if one medication offers better protection against cell loss than the other.
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:
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.
Exclusion Criteria:
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] · Drug: Timolol Maleate 0.25% Ophthalmic Solution
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] · Drug: Timolol Maleate 0.25% Ophthalmic Solution
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.
Also known as: Rhopressa
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.
Also known as: Timoptic
Change in GC soma density (cells/mm²)
Change in ganglion cell (GC) soma density during treatment with timolol versus netarsudil (Rhopressa)
Time frame: Baseline, 6 months, and 12 months
Changes in GC soma counts (number of cells)
Changes in ganglion cell (GC) soma counts during treatment with timolol versus netarsudil (Rhopressa)
Time frame: Baseline, 6 months, and 12 months
Changes in GCL thickness (micrometers (µm))
Changes in ganglion cell layer (GCL) thickness during treatment with timolol versus netarsudil (Rhopressa)
Time frame: Baseline, 6 months, and 12 months
Eligibility is decided by the study team. Share this record with your doctor or contact the team directly.
Contact study teamGet an email when the registry record changes — status, dates, results — or when someone posts here.
Sign in to followQuestions and observations about this study, from anyone following it. Not medical advice, and not a channel to the study team — their contact details are on the registry record.
Sign in to join the discussion. Reading takes no account; posting does. You choose a display name, and a pseudonym is the default.
Nothing here yet. If you are running this trial, taking part in it, or weighing whether to, this is the place to say so.
Brett King