Measuring the Effects of Rhopressa on Episcleral and Retinal Blood Flow in Ocular Hypertension and Glaucoma Suspects

Rhopressa effectively lowers intra-ocular pressure by improving conventional outflow and decreasing episcleral venous pressure. While this may result in improved episcleral venous flow, current methods to quantify episcleral blood flow in vivo are rudimentary and unable to accurately and precisely determine flow. Proof that Rhopressa effectively increases episcleral venous flow would differentiate it from other medications. Furthermore, this evidence could galvanize interest in the use of Rhopressa after popular Minimally Invasive Glaucoma Surgery (MIGS) procedures. In future studies, MIGS procedures could be used to improve the proximal outflow pathway, and Rhopressa to enhance distal outflow.

Specific Aim:

To determine the effect of Rhopressa on episcleral venous outflow and retinal blood flow in a cohort of treatment-naïve ocular hypertensive and glaucoma suspect patients.

Hypothesis:

Rhopressa increases episcleral venous flow and retinal blood flow from baseline at both 1 hour and 1 week after initiation of therapy.

Need/Relevance:

Rhopressa effectively lowers intra-ocular pressure by improving conventional outflow and decreasing episcleral venous pressure. While this may result in improved episcleral venous flow, current methods to quantify episcleral blood flow in vivo are rudimentary and unable to accurately and precisely determine flow. Proof that Rhopressa effectively increases episcleral venous flow would differentiate it from other medications. Furthermore, this evidence could galvanize interest in the use of Rhopressa after popular Minimally Invasive Glaucoma Surgery (MIGS) procedures. In future studies, MIGS procedures could be used to improve the proximal outflow pathway, and Rhopressa to enhance distal outflow.

Purpose/Aim:

The investigators have developed a technology to accurately and precisely determine episcleral and retinal blood flow in human subjects using ICG labeled erythrocytes via a technique the investigators have coined as Erythrocyte Mediated Angiography (EMA). The investigators propose conducting a pilot study to show the effect of Rhopressa on both improving episcleral blood flow as well as studying its effect on retinal blood flow. With lower intraocular pressure, and correspondingly higher ocular perfusion pressure, Rhopressa may also improve retinal blood flow.

Specific Aim:

To determine the effect of Rhopressa on episcleral venous outflow and retinal blood flow in a cohort of treatment-naïve ocular hypertensive and glaucoma suspect patients.

Hypothesis:

Rhopressa increases episcleral venous flow and retinal blood flow from baseline at both 1 hour and 1 week after initiation of therapy.

To test this hypothesis, the investigators will measure and compare episcleral venous and retinal blood flow at baseline, 1 hour after Rhopressa instillation and 1 week after initiation of Rhopressa.

Eligibility Criteria:
Inclusion Criteria:

* Patients at least 18 years of age.
* Patients must have ocular hypertension or be a glaucoma suspect.
* Patients must be treatment naïve without alternative study treatments or previous history of using topical IOP lowering agents.
* Patients must have an IOP of 24-30 mm Hg in the affected eye.
* Patients must have open angles on gonioscopy.
* Patients must be willing and able to comply with the protocol including providing informed consent.
* All patients will have at least one recorded visual field examination within 6 months of enrollment in the study. Visual fields will be assessed using the Hodapp-Andersen-Parish criteria.

Exclusion Criteria:

* Prior intraocular surgery other than uncomplicated cataract surgery.
* Allergy or history of adverse reaction to ICG, shellfish, or Iodine.
* Significant liver disease or uremia.
* Secondary glaucoma including exfoliation glaucoma, pigmentary glaucoma, or history of acute angle closure.
* Greater than 6 diopters of refractive error.
* Moderate or severe visual field deficits as per Hodapp-Anderson-Parish criteria.
* Any condition precluding imaging including reliable visual fields, disc photography, or use of study treatments including media opacity or tilted optic disk.
* Pregnant or nursing patients.