Proof of Concept Study for First-Sight Refractive Error Correction: Direct Comparison to Manifest Refraction and Autorefraction Results

Uncorrected refractive error is a frequent cause of visual impairment in the global
population. In 2006, the World Health Organization released global estimates on visual
impairment. According to their findings, there are approximately 314 million people in the
world whose vision is impaired. Of this population 90% of those individuals live in
developing countries and 153 million cases are believed to be due to uncorrected refractive
error. The impact of uncorrected refractive error is great, including, but not limited to,
loss of employment opportunities, inability to care for family, and inability to receive an
education. The challenge is to determine the most effective and accessible method of
detecting refractive error and dispensing spectacles for better vision.

In the clinical setting, refractive error is corrected by prescribing spectacles or contact
lenses on a daily basis. Typically the patient will first undergo autorefraction, in which a
computer-controlled machine is used to objectively calculate the refractive error present as
a starting point for the subjective refraction test. This machine, however, is cumbersome and
not easily transportable abroad. Typically the machine is held up to the patient's forehead
and they are asked to look into the machine at a distant object. While they are looking at
this object the machine calculates the refractive error. Next, the patient undergoes manifest
refraction, a subjective refractive test that requires the use of trial lenses and patient
responses to improve the results calculated by autorefraction, resulting in the best
corrected visual acuity for that patient and a prescription for the patient to receive
spectacles tailored to their need.

As a testimony to how prevalent uncorrected refractive error is in the developing world,
refractive error in Nigerian adults and the prevalence of spectacle use was studied. In an
article titled Refractive errors in Nigerian adults: prevalence, types and spectacle
coverage, researchers looked at types of refractive errors and the ability of off the shelf
spectacles to meet the corrective need in the 13,599 Nigerian adults. Patients underwent
autorefraction and a detailed clinical exam and it was discovered that uncorrected refractive
errors were responsible for 77.9% of visual impairment at the 20/40 to 20/60 level, and 57.1%
at the 20/60 to 20/200 level. It also found that spectacles could improve the vision of 1,279
adults in the 20/40 range and 882 participants at the 20/60 level. However, only 3-4% of
those individuals wore spectacles.

First-Sight is a simplified way to correct refractive error. It is easily portable, making it
accessible to remote areas of the world. Unlike the study cited above, First-Sight can be
brought to remote areas where clinics are not available and patients are not able to afford
to pay for the clinic visit. As it is a simplified technique, local health care workers may
easily be able to learn how to use First-Sight and dispense spectacles to those in need.
Lastly, the sponsor of First-Sight will provide the refracting kits and custom-made
spectacles at no cost to the health care workers and patients.

Inclusion Criteria:

- Subjects must be 19 years of age and older.

- A refractive error of -4.50 to +4.50 diopter spherical error and astigmatism up to
-1.50 diopters on manifest refraction and autorefraction as documented in the
patient's medical records.

- Best corrected visual acuity (BCVA) of 20/20 with manifest refraction.

- No known ocular pathology from previous clinical exams that may limit best corrected
visual acuity.

Exclusion Criteria:

- Refractive error greater than -4.50 or +4.50 diopter, or astigmatism greater than
-1.50 diopters.

- Known ocular (corneal, lenticular, vitreal, or retinal) pathology that may limit BCVA.

- Best corrected visual acuity with spectacles of 20/25 or worse.

- Any previous surgical or laser procedures that may limit BCVA

- 18 years of age and younger