New evidence warranted a change in the study design and study population group (inclusion/ exclusion criterion). We completed another clinical trial focused on subjects with headache symptoms but this particular clinical trial was terminated.

To understand the benefits of the neurolens Measurement Device and neurolens treatment as it pertains to treating symptoms related to Convergence Insufficiency. It is a Prospective randomized double masked two arm performed on a minimum of 100 to a maximum of 150 subjects identified as symptomatic (CISS questionnaire score equal to or greater than 16) done across 3-10 clinical sites. There are two subgroups: a minimum of 50 in each subgroup(subgroup 1: pre-presbyopic (18-40 years); subgroup 2: presbyopic subjects(41-60 years).

This study is a two-arm crossover study with two subgroups. Subjects will initially be assessed for their convergence insufficiency symptoms (convergence insufficiency symptom score (CISS v-15) questionnaire) and then are provided an updated refractive prescription and will wear them for 35 ± 5 days. Symptoms will be reassessed after the 35-day control break in. If the subject's symptoms have subsided, they will be exited from the study and will keep their lenses. Provided the subject has symptoms (CISS questionnaire score ≥ 16) after their 35-day use of their updated prescription and they continue to meet the inclusion/exclusion criteria they will proceed to the evaluation portion of the protocol. The first arm receiving neurolens first and the second arm receiving the control first. The control is a single vision or PAL lens which yields the BCDVA and BCNVA of a test subject with no prismatic correction. The neurolens prescribed prism will be based on the practitioner's Rx using the subject's best response to a prism trial lens and must be within a half prism diopter of the neurolens value output of the neurolens Measurement Device and providing the subject's BCDVA and BCNVA. Participants will come back after 35 day wear of their first test lens and the symptom questionnaire is reassessed. They will be now be crossed over to the second pair of study lenses (i.e. subjects in the first arm will not receive control lens and the ones in the second arm will not receive neurolens).Participants will come back after 35 day wear of their second test lens and the symptom questionnaire is reassessed for the final time.

Inclusion Criteria:

• Male or female, and between 18-60 years of age at the time of signing the informed consent.

• Best Corrected distance and near acuity are equal to or better than 20/25 Snellen Equivalent in each eye.

• Best Corrected distance and near binocular acuity are equal to or better than 20/25 Snellen Equivalent.

• Symptomatic as indicated by the CISS questionnaire (Score equal to or greater than 16)

• Updated distance spectacle prescription must match the following

  1. Spherical power inclusive between +4.00D to -8.00D
  2. Cylinder power no more than -4.00Dcyl
  3. ADD power i. Subgroup 1: No ADD ii. Subgroup2: minimum +1.00D ADD

• Subjects' eye alignment tests must match the following:

  a. Successful measurement on the neurolens Measurement Device (Acceptable MQI and a numerical neurolens Value, no Low MQI or Convergence Excess)

• Near point of convergence greater than or equal to 5cms

• Capable of committing to the duration of the study.

• Willing to comply with study procedures

Exclusion Criteria:

• Subjects who need a vertical prism.
• Previously has worn neurolenses.
• Subjects who need a near add less than 1.00D
• Use of contact lenses during the study
• Lack of binocular vision, including strabismus, amblyopia, or suppression.
• Greater than 20 prism diopter of eye misalignment.
• Aniseikonia greater than 3.00D spherical equivalent difference between eyes
• Prior ocular surgery that in the estimation of the practitioner induces corneal scarring (RK, Corneal Transplant, etc.) or prior surgery involving the extraocular muscles (strabismus surgery). Surgeries that do not affect these parameters such as LASIK, PRK, or pterygium surgery are allowed.
• Anterior segment conditions that could obfuscate or obscure reflections from the cornea, or reduce visual acuity, including but not limited to corneal scarring, large pinguecula, pterygium, keratoconus, dermatochalasis, ptosis, exophthalmos or cataract.
• Clinical dry eye (defined as tear break-up time of less than 5 seconds)
• Intraocular pressures greater than 25 mmHg in either eye or uncontrolled glaucoma
• Macular disease, or any posterior segment finding which in the opinion of the investigator is visually and/or clinically significant
• Change in acute or prophylactic migraine treatment medication or dosage within the previous two months.
• Diabetes with ocular manifestation
• Previous head or neck trauma (for instance, car accident, etc.) requiring medical intervention.
• Open lesions or sores around the chin or eyes that will make contact with the device and may be subject to contraction or spread of infection.
• Physical tremors or muscle spasms that prevent a subject from sitting still.
• A history of seizures or seizure disorder.
• Women who are pregnant or lactating at the time of the study entry
• Mental incapacity that prevents a subject from being able to follow simple instructions such as "look at the target."

We will be providing a backend read-only excel spreadsheet of the raw data that was entered on the digital data platform provided to the clinical site.

Data will be available along with the publication for at least 5 years.

On request.

Prospective randomized double masked two arm