Ocular Adaptation and Visual Performance for Accommodative Contact Lens

Not Applicable

Terminated

Brief Summary: Presbyopes (people who might have a significant loss of their ability to accommodate their crystalline lens in the eye) will be recruited to wear a test lens and perform typical clinical tests of visual acuity with different luminance levels and viewing distances/angles.

Detailed Description: In the proposed study we plan to recruit presbyopes (people who might have a significant loss of their ability to accommodate their crystalline lens in the eye) to wear a test lens and perform typical clinical tests of visual acuity with different luminance levels and viewing distances/angles. These are similar to the typical examinations conducted for regular contact lens wearers. Results of this testing will be used to evaluate the efficacy of test lenses and to provide additional information for revision of test lenses. If shown to provide adequate eye comfort and intended vision correction, this lens design has the potential of allowing tens of millions of presbyopes to adapt to contact lenses and significantly improve their vision and well-being.

Recruitment & Eligibility

Inclusion Criteria

Be between 40 and 65 years of age.
Have normal/corrected-to-normal monocular acuity of better than 20/25 for both eyes.
Have pupil diameter in regular lighting ≥ 2.5 mm.
Willing and able to wear multifocal contact lenses in both eyes.
Have a current optical prescription (obtained less than 2 years ago).
Have spherical equivalent correction equal to or higher than -1.00 Diopter and equal to or less than +0.50 Diopter.
Have cylindrical correction equal to less than 0.50 Diopter.

Exclusion Criteria

Have no prismatic correction.
Without any eye infection, inflammation, disease, or abnormality that contraindicates contact lens wear within the past 6 months.
No clinically significant ocular pathology (e.g., cataract, keratoconus, dry eye, diabetic retinopathy, or age-related macular degeneration)
Have no photosensitive disorders, including migraine and seizure.
Have no binocular dysfunction, including amblyopia, strabismus, and other binocular diseases.

Arm && Interventions

Group	Intervention	Description
Accommodative contact lens	Accommodative contact lens	The accommodative contact lens is composed of traditional hydrogel lens material but has an internal cavity to allow lens deformation that increases its refractive power at an downward angle.

Primary Outcome Measures

Name	Time	Method
Monocular Refractive Power	30 mins of wearing; non-dispensing.	Participants will wear the test lens and look at different downsize angles. The refractive power of the lens/eye combination will be measured with an open-field auto refractor.
Visual Acuity at 20 Degree Downsize Angles	30 mins of wearing; non-dispensing.	The resultant visual acuity at near at this down-gaze angle will be measured. This is achieved by having the subjects holding a new acuity chart at 40 cm distance, their heads upright and perpendicular to the ground, and their gazes rotated downward 20 degrees where the chart was located. The subjects then read out the optotypes (letters) on the chart to a size they cannot no only identify the letters. The lines of letters with which all letters can be identified is recorded as the corresponding level of acuity.

Secondary Outcome Measures