Effect of Negative Pressure on Pattern Electroretinography Readings

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.