Effect of Negative Pressure on Pattern Electroretinography Readings

Glaucoma is a leading cause of blindness worldwide. Intraocular pressure (IOP) remains the only modifiable risk factor for glaucoma. Without sufficient IOP lowering therapy, glaucoma induces retinal ganglion cell death and visual field loss. Pattern electroretinography (pERG) measurements directly correlate with retinal ganglion cell (RGC) signaling, providing an objective, repeatable, and non-invasive assessment of RGC function. The purpose of the study is to investigate the pERG changes associated with acute IOP reduction using the Mercury™ Multi-Pressure Dial (MPD). 10 patients will be enrolled. These subjects will have a best corrected visual acuity of 20/40 or better in both eyes and an established diagnosis of one of either mild/moderate OAG (open-angle glaucoma), OHT (ocular hypertension), or glaucoma suspect. Both eyes will be enrolled in the study. The study eye will receive a standardized 10 mmHg decrease in periorbital pressure via the Mercury™ Multi-Pressure Dial (MPD), and the fellow/control eye will receive no (zero) pressure application. Total google wear time will be 4.5 hours. Serial pERG measurements will be taken before, immediately after, and 2 hours after negative pressure application.


Eligibility Criteria:
Inclusion Criteria:

* Subjects capable of committing to the duration of the study and signing the informed consent.
* Subjects must be male or female and ≥ 22 years of age at the time of signing the informed consent.
* Subjects with orbital anatomy that permits a proper seal when goggles are placed over eyes.
* Subjects can tolerate ERG measurements.
* Subjects with a documented BCVA OU 20/40 or better AND a diagnosis of OHT, glaucoma suspect, or OAG in both eyes. OAG definition is inclusive of normal tension glaucoma, pseudoexfoliation glaucoma, and pigment dispersion. Both eyes require same diagnosis.
* Subjects with prior surgeries such as refractive surgeries (e.g., LASIK, PRK, SMILE), cataract surgery, cataract surgery with minimally invasive glaucoma surgery (MIGS), MIGS alone, trabeculectomy, or implantation of other glaucoma drainage devices can be included in the study; however, no other prior ocular surgeries are permitted.
* Subjects without lenticular opacities and/or trace (i.e. 1+) lenticular opacities.

Exclusion Criteria:

* Subjects with a history of allergy to primary study device material (i.e. silicone, anti-fog solution).
* Subjects with a history of any ocular disorder or condition in either eye that would likely interfere with the interpretation of the study results or subject safety (e.g., corneal transplant).
* Subjects with a history of any demyelinating disorder or condition that would likely interfere with the interpretation of the study results or subject safety (e.g. MS).
* Subjects with an untreated retinal detachment, retinal tears, macular degeneration, or any other fundus findings that may prevent accurate ERG measurements in either eye.
* Subjects with conjunctival chemosis in either eye.
* Subjects with eyelid edema.
* Subjects with a history of seizure disorder.
* Subjects with an eye infection.
* Subjects with moderate-severe (i.e. 2+, 3+, or 4+) lenticular opacities.