This is a multi-center, investigator blinded, randomized study designed to assess the efficacy, duration of effect, safety and tolerability of Luma Light System for plaque psoriasis. Two selected areas to be treated will be determined by the Investigator at Baseline. Excluded areas include the palms, the soles of the feet, the intertriginous areas, the knee, the elbow, the face and the scalp. Target Plaque Assessment (TPA), tolerability assessment and any adverse events (AEs) will be obtained at each visit. The subject may use topical prescriptions (steroids, vitamin D analogs, retinoids, etc.) for non-target plaques during this trial with approval of the investigator as long as they keep a 1" border around the target plaques where no prescription topical is applied. Any treatment that is not part of the trial that the subject uses for psoriasis should be noted in the subject's file.

Start of Observation Phase with Screening Visit: Subjects will be given an IRB approved consent to read and sign at the screening Visit. No study related procedures will be performed prior to signing this consent. The Investigator will review the inclusion/exclusion criteria, evaluate the Subject's medical history, before determining the Subject's eligibility to participate in the study. A pregnancy test will be performed for all females of childbearing potential at the Screening Visit. Prior to the trial start, each subject will undergo a minimum 2 weeks or maximum of 13 weeks Observation Phase (starting with Visit 1 Screening) during which the subject will be supplied a standard cleanser and lotion in order to evaluate the stability of the plaque severity prior to entering the Active Treatment Phase. The Observation Phase will be up to 13 weeks if the subject needs to taper off an oral medication or biologic (see Washout and Excluded Medications section).

Start of Active Treatment Phase with Baseline Visit: If the Subject is determined to be eligible for the study, he/she will return to the clinic for the Baseline Visit. At this visit inclusion/exclusion criteria will be confirmed, patient will be enrolled in the study, randomization of the plaques will occur and baseline assessments will be performed including TPA. The test product will be dispensed, the user will be trained on how to use the product and the first treatment will be applied.

The Active Treatment Phase will be 6 weeks or until target plaque has cleared, whichever comes first. During the Active Treatment Phase, the plaque randomized to Arm B will receive the active occlusive hydrogel patch and will be changed every 5 days or less as needed. During the Active Treatment Phase, the plaque randomized to Arm A will receive the window patch and replaced as needed. The light will be applied to the target plaque assigned to Arm B every day with the hydrogel patch in place. The subject will return to the clinic every two weeks (Visit 3, 4 and 5) for assessments. Subjects who terminate early will be asked to complete all Week 6/ET assessments prior to commencement of any alternative therapy for psoriasis (if possible). Subjects who discontinue from the study during the Active Treatment Phase may be replaced and only will be followed if an AE is present.

Start of Follow-up Phase: Subjects will return for efficacy and safety follow-up visits at 8 week intervals after the Active Treatment Phase for 24 weeks (Visit 6, 7 and 8) to assess durability of remission. If subject decides to start active treatment with a prescription product on a plaque that was treated during the Active Treatment Phase (not including supplied lotion and cleanser, shampoos for hair or their normal topical therapeutic products to psoriatic areas that are not part of the study treatment areas) then that target plaque will no longer considered to be in remission. No systemic treatments will be allowed during the Follow-up Phase but if the subject or physician determines that it is necessary, the subject will no longer be considered in remission at the time of commencement of the systemic treatment. If the subject uses a prescription product on a target plaque or starts a systemic treatment, the investigator will capture why this occurs.