CompletedPhase 1ACTRN12620001259932

Safety and tolerability trial of an eye drop treatment for short sightedness (myopia)

Phase 1 safety and tolerability trial of levodopa eye drops for the treatment of short sightedness (myopia)

Sponsor

University of Canberra

Enrollment

30 participants

Start Date

Apr 1, 2021

Study Type

Interventional

Conditions

Myopia

Summary

This will be a first-in-human safety and tolerability trial of a novel ophthalmic solution for the treatment of the visual disorder myopia (short-sightedness). Myopia has been hypothesised to be driven by a reduction in dopamine levels within the eye. Over the past five decades, levodopa (the precursor to dopamine) has been the primary treatment for neurological disorders involving the dysregulation of the dopaminergic system, such as Parkinson’s disease. Before we can examine the efficacy of this compound at inhibiting myopia, this study will assess the safety and tolerability of levodopa as a reformulated eye drop solution.

Eligibility

Sex: MalesMin Age: 18 YearssMax Age: 30 Yearss

Inclusion Criteria4

Males aged 18-30.
Visual acuity, measured in each eye without cycloplegia, of 0.1 logMAR or 6/7.5 Snellen equivalent.
Cycloplegic auto-refraction in the range of -5.0 to +3.0 Dioptres (Spherical Equivalent).
Not be undertaking treatment to inhibit the progression of myopia (including spectacle wear) for at least 12 weeks prior to enrolment. Optical correction for a refractive error is allowed, although contact lenses cannot be worn during the trial period.

Exclusion Criteria16

Evidence of anterior/posterior segment ocular disease/disorder.
Currently undergoing visual therapy.
Treatment with topical atropine or any other topical therapeutic solution (except over-the-counter artificial tears) within the past 12 weeks.
Current treatment with monoamine oxidase inhibitors, antihypertensives, anti-depressants, phenothiazines (antipsychotics), butyrophenones (dopamine agonists), risperidones and isoniazids (antipsychotics).
Prior intraocular or refractive surgery.
History of narrow angle glaucoma or evidence of narrow anterior chamber angles on ophthalmic exam.
History of dystonic reactions (involuntary muscle contraction).
Current requirement to take oral iron supplements including multivitamins containing iron.
Current treatment with medication for attention deficient hyperactivity disorder (ADHD).
Known gastrointestinal, liver, or renal disease/impairment.
History of melanoma or undiagnosed suspicious skin lesions.
Allergy and/or hypersensitivity to Levodopa or Carbidopa.
Known psychological problems.
Prior Levodopa or Levodopa/Carbidopa treatment.
Prior bronchial asthma or pulmonary disease.
Physician prescribed diet high in protein.

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Interventions

This trial will be a first-in-human placebo controlled, double-blind randomised clinical trial to assess the safety and tolerability of a levodopa:carbidopa ophthalmic solution in young adults (males, aged 18-30) treated for a period of 4 weeks (28 days). For treatment, this study will follow a paired eye design. Participants will administer the active ophthalmic solution described below to one eye and the placebo solution to the other eye. Participants will be split into two arms (arm 1 - high dose ophthalmic solution, arm 2 – low dose ophthalmic solution). Participants will be randomly assigned to either arm, with which eye to be treated and which to act as a control also randomised. Formulation A topical eye drop solution containing levodopa, carbidopa, an antioxidant (ascorbic acid) and a preservative (benzalkonium chloride (BAK)) dissolved in a saline solution. Dose per day (80 microliter administered volume) Arm 1 (high dose): levodopa (2.4 micromoles/ 0.4 mg), carbidopa (0.6 micromoles/ 0.1 mg), ascorbic acid (0.1% w/v) and BAK (0.1% w/v). Arm 2 (low dose): levodopa (1.2 micromoles/ 0.2 mg), carbidopa (0.3 micromoles/ 0.05 mg), ascorbic acid (0.1% w/v) and BAK (0.1% w/v). Duration Administered as two drops (80 microliters total) to the corneal surface once per day (morning) for a period of 4 weeks (28 days). Mode Topical eye drops Adherence Each participant will keep a diary detailing their daily use of the trial medication. All dropper bottles will also be weighed before commencement and at the end of the treatment period as a measure of adherence.