None listed
Conditions
Brief summary
The purpose of this study is to assess how the accommodative system (the focusing mechanism) of the eye extracts the directional information from the visual experience, We will be assessing the accommodative system function using a non-contact instrument where you are asked to look at a target provided on a computer screen.
Interventions
This is a prospective cross sectional observational study design. There will be 3 visits comprising baseline and two visits to assess the ocular accommodation. The duration between each visit can range from 3 days to 7 days. Short term accommodative measurements as done in this study (e.g. 45 minutes to 60 minutes with regular intervals of breaks) are not influenced by duration between the measurements given it is more than a day. However, we chose this specific time range to balance the measur
This is a prospective cross sectional observational study design. There will be 3 visits comprising baseline and two visits to assess the ocular accommodation. The duration between each visit can range from 3 days to 7 days. Short term accommodative measurements as done in this study (e.g. 45 minutes to 60 minutes with regular intervals of breaks) are not influenced by duration between the measurements given it is more than a day. However, we chose this specific time range to balance the measurement consistency and the participant’s feasibility. All visits including the contact lens assessment will be performed by an optometrist and will be approximately 60 minutes in duration. Baseline visit will comprise visual acuity assessment and accommodative-convergence responses with habitual refractive correction. Auto-refraction, subjective refraction with visual acuity measurement and ocular assessment with a slitlamp bio microscope (a specialized microscope for viewing the eye) will be performed with no contact lens on eye. Rest of the study visits will have the accommodative measurements using a non-contact binocular open field autorefractor. In the final visit the participant will be asked to wear a custom designed coloured soft contact lens (a clear transparent centre zone, which is surrounded by a wide black ring to block out all light outside the central vision-pinhole contact lens) in order to correct the optical aberrations of the eye. The purpose of the soft contact lens is solely to correct the monochromatic aberration but not to evaluate the efficacy/effect of the contact lens in any manner. This contact lens otherwise would act like the spectacle lens/regular contact lens to correct the refractive error with an added advantage of correcting the optical aberrations. The pinhole approach to correct the monochromatic aberrations has been well established in the literature. There are no associated risks involved with these procedures. However the contact lens use might cause minor ocular discomfort which includes tearing, burning sensation. But, that is the normal protective mechanism of the eye and the symptoms will reduce by its own in 5-10 min times. This is naturally experienced by any naive contact lens wearer. An adequate time will be given to the participant to adapt for the lenses. In case of the persistent symptoms Optometry clinic staff will be there to assist with the necessary care.This contact lens fitting will be assessed by an Optometrist and appropriate adaptation time will be given to the participant before commencing any measurements. The lens is worn for short duration and each lens is disposed after the use. The accommodation will be measured while the participant is asked to look at the target presented on the computer screen. The screen is placed in front of the participant’s primary gaze position. The target will be varied in size and colour while the participant task is to maintain a fixation on the target. The participant will be given regular verbal instructions to maintain the fixation. The participant can also blink normally while the measurement in progress.
Sponsors
Brien Holden Vision Institute
Study design
Allocation
Non-randomised trial
Primary purpose
Diagnosis
Eligibility
Sex/Gender
All
Age
18 Years to 30 Years
Healthy volunteers
Yes
Inclusion criteria
Able to read and comprehend English and give informed consent as demonstrated by signing a record of informed consent. Be between 18-30 years old, male or female. Willing to comply with the clinical trial as directed by the Investigator. Have ocular health findings considered to be “normal” and which would not prevent the participant from safely wearing contact lenses. Be an emmetrope (+0.50 DS to -0.50 DS), hyperope(+0.75 DS to +6.00 DS) or a myope (-0.75 DS to -6.00 DS) with or without astigmatism less than =<1.00DC Be correctable to better than 0.20 log MAR in each eye with single vision contact lenses. Be able to insert and remove contact lenses.
Exclusion criteria
Any pre-existing ocular irritation, injury or condition (including infection or disease) of the cornea, conjunctiva or eyelids that would preclude contact lens fitting and safe wearing of contact lenses. Any systemic disease that adversely affects ocular health e.g. diabetes, Graves disease, and auto immune diseases such as ankylosing spondylitis, multiple sclerosis, Sjogrens syndrome and systemic lupus erythematosus. Conditions such as systemic hypertension and arthritis do not automatically exclude prospective participants. Use of or a need for any systemic medication or topical medications which may alter normal ocular findings / are known to affect a participant’s ocular health / physiology or contact lens performance either in an adverse or beneficial manner at enrolment and/or during the clinical trial. Previous corneal refractive surgery. Previous surgery on the extra ocular muscles. Contraindications to contact lens wear. Known allergy or intolerance to ingredients in any of the clinical trial products. Currently enrolled in another clinical trial. Pregnancy*. The Investigator may, at his discretion, exclude anyone who they believe may not be able to fulfil the clinical trial requirements or it is believed to be in the participant’s best interests. *Formal testing of pregnancy is not required. A participant’s verbal report is sufficient.
Outcome results
None listed