Night Vision ComplaintsPhase 2NCT01703559

The Safety and Efficacy of Phentolamine Mesylate Ophthalmic Solution in Subjects With Severe Night Vision Disturbances

A Phase 2 study testing Phentolamine Mesylate Ophthalmic Solution 1.0% and Phentolamine Mesylate Ophthalmic Solution 0.5% in people with Night Vision Complaints and Decrease in Night Vision, run by Opus Genetics, Inc at 1 site in United States.

Completed

Finished. The study has ended and is not enrolling. Results may be posted on the official record.

Official record

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Trial summary

The objectives of this study are: To evaluate the efficacy of phentolamine mesylate 0.5% and 1.0% ophthalmic solution (Nyxol) in the treatment of night vision complaints, including reduced contrast sensitivity To evaluate the ocular and systemic safety of phentolamine mesylate 0.5% and 1.0% ophthalmic solution (Nyxol)… Read more about this study

Who is it for?: Ages 18 to 45 yearsHealthy volunteers can take part
Conditions the study is for: Night Vision Complaints, Decrease in Night Vision, Disturbance; Vision, Loss
What is being tested?: Phentolamine Mesylate Ophthalmic Solution 1.0% and Phentolamine Mesylate Ophthalmic Solution 0.5%
Could I receive a placebo?: Yes, some participants may receive a placebo
How many people: 60 participants
Where: 1 siteUnited States
Study dates: 9 Sep 2011to 30 Apr 2012
Phase: Phase 2
Are there results?: Yes, posted in the registrySummary in the doctors' view

Key requirements

Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.

Ages 18 to 45 years
All sexes
Healthy volunteers accepted
Adult

Who may be able to join

18 to 45 years of age experiencing severe night vision difficulty (as reported subjectively)
0.3 log improvement at least 1 eye using the Holladay Automated Contrast Sensitivity System (HACSS™) test at 2 of 4 spatial frequencies (3, 6, 12, and 18 cycles per degree) under low and high mesopic room illumination with glare
Photopic visual acuity (corrected or uncorrected) of 20/25 or better
Able and willing to give informed consent and comply with all protocol-mandated procedures

Who cannot join

Cataracts (nuclear sclerosis or anterior subcapsular) of 1+ or greater
Contact lens wear within 4 weeks of enrollment
Ocular trauma within the past 6 months, or ocular surgery or laser treatment within the past 3 months
Refractive surgery or cataract surgery in either eye
Use of ocular medication within 4 weeks of Visit 1
Clinically significant ocular disease (e.g., corneal edema, uveitis, severe keratoconjunctivitis sicca, glaucoma, retinal degenerative disease) which might interfere with the study

Show all 17Show fewer

Any abnormality preventing reliable applanation tonometry of either eye
Central corneal thickness greater than 600 µ
Known hypersensitivity or contraindication to PM, or any component of the formulation, or to topical anesthetics.
Contraindications to phentolamine (including history of myocardial infarction, cerebrovascular spasm, cerebrovascular occlusion, coronary insufficiency, angina, or other evidence suggestive of coronary artery disease)
Low blood pressure: systolic < 100 mm Hg or diastolic < 60 mm Hg
A history of heart rate abnormalities, such as tachycardia or arrhythmias.
Clinically significant systemic disease (e.g., uncontrolled diabetes, myasthenia gravis, hepatic, renal, cardiovascular, or endocrine disorders) which might interfere with the study
Use of any systemic alpha adrenergic antagonists up to 4 weeks prior to screening or during the study
Changes of systemic medication that could have a substantial effect on ocular autonomic pupil tone 4 weeks prior to screening, or anticipated during the study
Participation in any investigational study within the past 30 days
Women of childbearing potential who are pregnant, nursing, planning a pregnancy, or not using a medically acceptable form of birth control. An adult woman is considered to be of childbearing potential unless she is 1 year post-menopausal or 3 months post-surgical sterilization. All females of childbearing potential must have a negative serum pregnancy test result at the screening examination and must not intend to become pregnant during the study

Trial locations and contacts

1 site in 1 country.

United States1 site

Celerion
Phoenix, Arizona, 67230

Other trials in United States

About this study

Official title: Double-Masked Parallel Evaluation of the Safety and Efficacy of Phentolamine Mesylate Ophthalmic Solution in Subjects With Severe Night Vision Disturbances

The objectives of this study are:

To evaluate the efficacy of phentolamine mesylate 0.5% and 1.0% ophthalmic solution (Nyxol) in the treatment of night vision complaints, including reduced contrast sensitivity
To evaluate the ocular and systemic safety of phentolamine mesylate 0.5% and 1.0% ophthalmic solution (Nyxol) compared to its vehicle, a sterile, isotonic, buffered aqueous solution containing mannitol and sodium acetate

Read the detailed description

Randomized, double-masked, multiple dose Phase 2 parallel evaluation of the safety and efficacy of phentolamine mesylate (PM) ophthalmic solution in 60 subjects with severe night vision complaints, evaluating ocular and systemic safety and efficacy following administration of phentolamine mesylate (.05% or 1%) in both eyes for 15 days.

Subjects were randomized into three groups with a 1:1:1 randomization. The groups received either (1) phentolamine mesylate ophthalmic solution 0.5%, (2) phentolamine mesylate ophthalmic solution 1.0%, or (3) placebo, once daily (QD) for 15 days. The treatment period was 15 days, plus 6 additional days over the next 14 days. After 15 days, all subjects were given the opportunity to receive an additional 6 doses of 1.0% phentolamine mesylate to be taken once daily as needed over the next two weeks. There was a post-dosing follow-up evaluation 7 days after the last dose. Study participants completed a night vision questionnaire at pre-treatment and after 15 and 29 days.

Efficacy evaluations included contrast sensitivity (mesopic, with and without glare), mesopic distance high contrast visual acuity (HCVA) and mesopic distance low contrast visual acuity (LCVA). Safety evaluations included photopic distance HCVA, a complete ophthalmic examination and measurement of heart rate and blood pressure.

Conditions: Night Vision Complaints, Decrease in Night Vision, Disturbance; Vision, Loss
Being tested: Phentolamine Mesylate Ophthalmic Solution 1.0%, Phentolamine Mesylate Ophthalmic Solution 0.5%, Phentolamine Mesylate Ophthalmic Solution Vehicle (Placebo)
Keywords: Glare, Starbursts, Halos, Reduced Contrast Sensitivity, Night Vision Disturbances, NVD, NVDs

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

Phentolamine Mesylate Ophthalmic Solution 1.0%Drug
Also called Nyxol®, Nyxol
Phentolamine mesylate (Nyxol) ophthalmic solution 1.0% is a non-selective alpha-1 and alpha-2 adrenergic antagonist
Phentolamine Mesylate Ophthalmic Solution 0.5%Drug
Also called Nyxol®, Nyxol
Phentolamine mesylate (Nyxol) ophthalmic solution 0.5% is a non-selective alpha-1 and alpha-2 adrenergic antagonist
Phentolamine Mesylate Ophthalmic Solution Vehicle (Placebo)Other
Placebo (vehicle) is a sterile, isotonic, buffered aqueous solution containing mannitol and sodium acetate

Study groups in NCT01703559
Study group	Role	What they receive
Placebo	Placebo comparator	Administered once daily in both eyes for 15 days Receives: Other: Phentolamine Mesylate Ophthalmic Solution Vehicle (Placebo)
Phentolamine Mesylate Ophthalmic Solution 0.5%	Experimental	Administered once daily in both eyes for 15 days Receives: Drug: Phentolamine Mesylate Ophthalmic Solution 0.5%
Phentolamine Mesylate Ophthalmic Solution 1.0%	Experimental	Administered once daily in both eyes for 15 days Receives: Drug: Phentolamine Mesylate Ophthalmic Solution 1.0%

What is being measured

The primary outcome is the main question the study is designed to answer.

Proportion of Eyes With ≥ 0.3 Log Increase in Mesopic Contrast Sensitivities for at Least 2 HACSS Frequencies
Proportion of eyes with an increase ≥ 0.3 log (2 or more patches) in mesopic contrast sensitivity with glare at two or more frequencies at 1.5, 3, 6, 12, and 18 cycles per degree, measured with the HACSS methodology (categorical analysis)
Measured: Postdose Day 1, 4, 8, 15, and Day 15 (LOCF=Last Observation Carried Forward)

Secondary outcomes (6)

Pupil Diameter - Change From Day 1 Pre-Dose Baseline
Measured: Day 1 post-dose and Days 4, 8, and 15
Mean Mesopic Contrast Sensitivity With Glare at Frequencies of 1.5, 3, 6, 12, and 18 Cycles Per Degree, Measured With the HACSS Methodology in LogCS Scale - Change From Day 1 Pre-Dose Baseline
At screening, contralateral illumination contrast sensitivity (HACSS) was measured to determine subject/eye eligibility. The Day 1 predose HACSS LogCS value served as the baseline for assessing improvement. At each post-dose visit (Days 1, 4, 8, 15), eyes with an improvement of at least 0.3 LogCS in mesopic contrast sensitivity with glare compared to baseline were summarized across all 5 frequencies (1.5, 3, 6, 12, and 18 cycles per degree). The Log CS (Logarithmic Contrast Sensitivity) scale measures how faintly an object can be distinguished from its background, calculated as the logarithm of contrast sensitivity (CS = 1 ÷ contrast threshold). Higher values indicate the ability to see highly faded, low-contrast images.
Measured: 15 Days
Mesopic Contrast Sensitivity Without Glare at 1 or More Frequencies at 1.5, 3, 6, 12, and 18 Cycles Per Degree, Measured With the HACSS Methodology in LogCS Scale - Mean Change From Day 1 Pre-Dose Baseline
At screening, contralateral illumination contrast sensitivity (HACSS) was measured to determine subject/eye eligibility. The Day 1 predose HACSS LogCS value served as the baseline for assessing improvement. Only eyes with at least 0.3 LogCS improvement at 2 or more frequencies were counted as showing overall improvement. At each postdose visit (Days 1, 4, 8, 15), eyes with an improvement of at least 0.3 LogCS in mesopic contrast sensitivity with glare compared to baseline were across all 5 frequencies 1.5, 3, 6, 12, and 18 cycles per degree.
Measured: Day 1 post-dose and Days 4, 8, and 15
Mesopic Distance High Contrast Visual Acuity (HCVA), Measured With Electronic Early Treatment Diabetic Retinopathy Study (eETDRS) Charts - Change From Day 1 Pre-Dose Baseline
Measured: Day 1 post-dose and Days 4, 8, and 15
Mesopic Distance Low Contrast Visual Acuity (LCVA), Measured With eETDRS Charts - Change From Day 1 Pre-Dose Baseline
Measured: Day 1 post-dose and Days 4, 8, and 15
Subjective Evaluations of Vision (NEI Vision Function) at Follow-up (Day 32)
NEI visual functioning questionnaire-25 (VFQ-25) Adapted for Dim Light Vision was conducted at the follow-up visit on Day 32. The frequency of categorical answers was summarized by treatment for each question. The questions are on a scale that ranges from 1-2, 1-2, 1-5, or 1-6 with 1 being the best outcome and 6 being the worst. Q14, Q15: 1-2; Q1, Q3, Q16, Q17, Q18, Q19, Q20, Q21, Q22, Q23: 1-5; Q2, Q4, Q5, Q6, Q7, Q8, Q9, Q10, Q11, Q12, Q13, Q14a, Q14b, Q14c, Q15, Q15a: 1-6. Questions 2 through 15a on the VFQ related to the subject's assessment of how much difficulty, if any, the subject has doing certain activities in dim light or at night, particularly driving (Questions 14c, 15, and 15a); the remaining questions related to how things the subject does may be affected by their vision in dim light or at night.
Measured: Day 32

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

9 Sep 201130 Apr 2012

First posted10 Oct 2012 (estimated)
Study start9 Sep 2011
Primary completion16 Apr 2012
Study completion30 Apr 2012

Resources

Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
Posted resultsParticipant flow, outcome measures and adverse events reported by the sponsor.
Other trials for Night Vision ComplaintsStudies of the same condition, open and under way.
What the trial phases meanHow a treatment moves from first tests in people to approval.

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design

Study type: Interventional
Phase: Phase 2
Primary purpose: Treatment
Allocation: Randomised
Intervention model: Parallel groups
Masking: Quadruple blind
Who is masked: Participant, Care provider, Investigator, Outcomes assessor
Enrolment: 60 participants (actual)

IDs, dates and publications

ClinicalTrials.gov ID: NCT01703559
Sponsor's protocol ID: OP-NYX-01a2
Status last verified: Oct 2026
First submitted: 18 May 2012
Last updated: 30 Oct 2026
Results posted: Yes, on ClinicalTrials.gov
Data monitoring committee: No
FDA-regulated drug: Yes
FDA-regulated device: No
Individual data sharing: No

Study at a glance

From the registry record, last updated by the sponsor on 30 Oct 2026. Recruitment status is as the sponsor reported it: confirm with the study team.

Official title: Double-Masked Parallel Evaluation of the Safety and Efficacy of Phentolamine Mesylate Ophthalmic Solution in Subjects With Severe Night Vision Disturbances
ClinicalTrials.gov ID: NCT01703559
Acronym / sponsor ID: OP-NYX-01a2
Conditions: Night Vision Complaints, Decrease in Night Vision, Disturbance; Vision, Loss
Keywords: Glare, Starbursts, Halos, Reduced Contrast Sensitivity, Night Vision Disturbances, NVD, NVDs
Phase: Phase 2
Study type: Interventional
Recruitment status: Completed
Enrolment: 60 participants (actual)
Lead sponsor: Opus Genetics, IncIndustry (pharma, biotech, devices)
Study start: 9 Sep 2011 (actual)
Primary completion: 16 Apr 2012 (actual)
Study completion: 30 Apr 2012 (actual)
First posted: 10 Oct 2012 (estimated)
Results: Posted 8 Oct 2026

Clinical summary

The research question as the sponsor registered it. This describes what the study plans to test, not what it found.

The objectives of this study are:

To evaluate the efficacy of phentolamine mesylate 0.5% and 1.0% ophthalmic solution (Nyxol) in the treatment of night vision complaints, including reduced contrast sensitivity
To evaluate the ocular and systemic safety of phentolamine mesylate 0.5% and 1.0% ophthalmic solution (Nyxol) compared to its vehicle, a sterile, isotonic, buffered aqueous solution containing mannitol and sodium acetate

Detailed description

Study design

Primary purpose: Treatment
Allocation: Randomised
Intervention model: Parallel groups
Masking: Quadruple blind (participant, care provider, investigator, outcomes assessor)
Number of arms: 3

Arm	Type	Receives
Placebo	Placebo comparator	Other: Phentolamine Mesylate Ophthalmic Solution Vehicle (Placebo)Administered once daily in both eyes for 15 days
Phentolamine Mesylate Ophthalmic Solution 0.5%	Experimental	Drug: Phentolamine Mesylate Ophthalmic Solution 0.5%Administered once daily in both eyes for 15 days
Phentolamine Mesylate Ophthalmic Solution 1.0%	Experimental	Drug: Phentolamine Mesylate Ophthalmic Solution 1.0%Administered once daily in both eyes for 15 days

Who may qualify

Ages: 18 to 45 years
Sex: All
Healthy volunteers: Accepted
Age groups: Adult

Key inclusion criteria (4 listed)

18 to 45 years of age experiencing severe night vision difficulty (as reported subjectively)
0.3 log improvement at least 1 eye using the Holladay Automated Contrast Sensitivity System (HACSS™) test at 2 of 4 spatial frequencies (3, 6, 12, and 18 cycles per degree) under low and high mesopic room illumination with glare
Photopic visual acuity (corrected or uncorrected) of 20/25 or better
Able and willing to give informed consent and comply with all protocol-mandated procedures

Key exclusion criteria (17 listed)

Cataracts (nuclear sclerosis or anterior subcapsular) of 1+ or greater
Contact lens wear within 4 weeks of enrollment
Ocular trauma within the past 6 months, or ocular surgery or laser treatment within the past 3 months
Refractive surgery or cataract surgery in either eye
Use of ocular medication within 4 weeks of Visit 1

Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.

Interventions

Intervention	Type	Arms
Phentolamine Mesylate Ophthalmic Solution 1.0%Also: Nyxol®, NyxolPhentolamine mesylate (Nyxol) ophthalmic solution 1.0% is a non-selective alpha-1 and alpha-2 adrenergic antagonist	Drug	Phentolamine Mesylate Ophthalmic Solution 1.0%
Phentolamine Mesylate Ophthalmic Solution 0.5%Also: Nyxol®, NyxolPhentolamine mesylate (Nyxol) ophthalmic solution 0.5% is a non-selective alpha-1 and alpha-2 adrenergic antagonist	Drug	Phentolamine Mesylate Ophthalmic Solution 0.5%
Phentolamine Mesylate Ophthalmic Solution Vehicle (Placebo)Placebo (vehicle) is a sterile, isotonic, buffered aqueous solution containing mannitol and sodium acetate	Other	Placebo

Primary outcome

Proportion of Eyes With ≥ 0.3 Log Increase in Mesopic Contrast Sensitivities for at Least 2 HACSS Frequencies
Time frame: Postdose Day 1, 4, 8, 15, and Day 15 (LOCF=Last Observation Carried Forward)
Proportion of eyes with an increase ≥ 0.3 log (2 or more patches) in mesopic contrast sensitivity with glare at two or more frequencies at 1.5, 3, 6, 12, and 18 cycles per degree, measured with the HACSS methodology (categorical analysis)

6 secondary outcomes

Pupil Diameter - Change From Day 1 Pre-Dose Baseline
Time frame: Day 1 post-dose and Days 4, 8, and 15
Mean Mesopic Contrast Sensitivity With Glare at Frequencies of 1.5, 3, 6, 12, and 18 Cycles Per Degree, Measured With the HACSS Methodology in LogCS Scale - Change From Day 1 Pre-Dose Baseline
Time frame: 15 Days
Mesopic Contrast Sensitivity Without Glare at 1 or More Frequencies at 1.5, 3, 6, 12, and 18 Cycles Per Degree, Measured With the HACSS Methodology in LogCS Scale - Mean Change From Day 1 Pre-Dose Baseline
Time frame: Day 1 post-dose and Days 4, 8, and 15
Mesopic Distance High Contrast Visual Acuity (HCVA), Measured With Electronic Early Treatment Diabetic Retinopathy Study (eETDRS) Charts - Change From Day 1 Pre-Dose Baseline
Time frame: Day 1 post-dose and Days 4, 8, and 15
Mesopic Distance Low Contrast Visual Acuity (LCVA), Measured With eETDRS Charts - Change From Day 1 Pre-Dose Baseline
Time frame: Day 1 post-dose and Days 4, 8, and 15
Subjective Evaluations of Vision (NEI Vision Function) at Follow-up (Day 32)
Time frame: Day 32

Results and safety

Results posted to the registry on 8 Oct 2026, as reported by the sponsor. Figures are copied from the record, not re-analysed. Full results on ClinicalTrials.gov.

Participant flow

Group	Started	Completed
Placebo	20	18
Phentolamine Mesylate Ophthalmic Solution 0.5%	20	20
Phentolamine Mesylate Ophthalmic Solution 1.0%	20	20

Primary outcome: Proportion of Eyes With ≥ 0.3 Log Increase in Mesopic Contrast Sensitivities for at Least 2 HACSS Frequencies

Time frame: Postdose Day 1, 4, 8, 15, and Day 15 (LOCF=Last Observation Carried Forward). Count of units. Unit: Eyes

Measure	Placebo n = 20	Phentolamine Mesylate Ophthalmic Solution 0.5% n = 20	Phentolamine Mesylate Ophthalmic Solution 1.0% n = 20
Day 1 Postdose	5	8	3
Day 4 Postdose	6	7	4
Day 8 Postdose	7	10	9
Day 15 Postdose	6	15	11
Day 15 Postdose (LOCF)	7	15	11

Population analysed: Lost Data for 1 subject from Day 8 for placebo and 0.5% PMOS

6 secondary outcomes are reported in the full results.

Adverse events

Time frame: Adverse events were monitored throughout the study (from time of admission to the clinic through the Follow-up visit on Day 32) until resolution.. Other adverse events reported at 0% frequency or more

Group	Serious adverse events	Other adverse events	Deaths
Placebo	0 of 20 (0%)	15 of 20 (75%)	0 of 20
Phentolamine Mesylate Ophthalmic Solution 0.5%	0 of 20 (0%)	16 of 20 (80%)	0 of 20
Phentolamine Mesylate Ophthalmic Solution 1.0%	0 of 20 (0%)	17 of 20 (85%)	0 of 20
Period 2 - 1.0% Phentolamine Mesylate Ophthalmic Solution	0 of 57 (0%)	13 of 57 (22.8%)	0 of 57

Loading the posted results from ClinicalTrials.gov…

Research links

Official record on ClinicalTrials.govLast updated by the sponsor 30 Oct 2026.
Posted resultsParticipant flow, baseline, all outcome measures and adverse events.
Individual participant dataSharing planned: No

Referral and contact

AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.

The record lists no contact. Use the official record to reach the sponsor.

1 site in 1 country: see every site and its status.

Questions about this trial

What is this clinical trial studying?

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

The sponsor lists 4 inclusion and 17 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.

Is this clinical trial currently recruiting?

The record says: finished, as of the sponsor's last update on 30 Oct 2026. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

What does this phase mean?

Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.

Not every study follows the same path, and some studies (observational studies, device studies) have no phase.

Are results available for this study?

Yes. Results are posted in the registry (first posted 8 Oct 2026). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.

How can a doctor refer a patient or contact the research team?

The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Proportion of Eyes With ≥ 0.3 Log Increase in Mesopic Contrast Sensitivities for at Least 2 HACSS Frequencies (time frame: Postdose Day 1, 4, 8, 15, and Day 15 (LOCF=Last Observation Carried Forward)). It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT01703559.

Does a listing mean the treatment is approved or proven to work?

No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.

How often is this information updated?

AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 30 Oct 2026.