Clinical Evaluation of CATS Tonometer Prism

Study Overview
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Brief Summary
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Prospective, open-labeled, randomized, controlled, multicenter study at two clinical investigative sites in Tucson, Arizona. The subjects will undergo intraocular pressure measurement with the CATS tonometer prism and the Goldmann applanation tonometer prism (GAT). Seventy-five (75) Subjects 18 and older and will be enrolled. Subjects will be screened based on standard of care vision examination at the clinical investigation sites. All subjects will undergo a standard ophthalmic exam and informed consent. IOP will be measured using a Goldmann tonometer armature with both the standard flat GAT prism and the modified curved CATS prism alternately inserted. The only additional measurement is central corneal thickness (CCT) which is used to correct for one of the corneal biomechanical errors seen in the GAT prism and is currently standard of care.

Conditions
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Ocular Hypotension

Intervention / Treatment
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* Device: CATS tonometer prism
* Device: Goldmann Tonometer prism


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Written informed consent (and assent when applicable) obtained from subject or subject's legal representative and ability for subject to comply with the requirements of the study. Male and female patients, at least 18 years of age Exclusion Criteria: Subject has undergone ocular surgery within the last 3 months Uncontrolled systemic disease that in the opinion of the Investigator would put the subject's heath at risk Pregnant or nursing women Subjects with only one functional eye Those with one eye having poor or eccentric fixation Eyes displaying an oval contact image Those with corneal scarring or who have had corneal surgery including corneal laser surgery Microphthalmos Buphthalmos Contact lens wearers Severe Dry eyes Lid squeezers - blepharospasm Nystagmus Keratoconus Any other corneal or conjunctival pathology or infection. Central corneal thickness between 0.600 mm and 0.500 mm (more than 2 standard deviations about the human mean)

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Diagnostic
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Goldmann Tonometer<br>determine if the CATS tonometer prism effectively reduces sensitivity to IOP errors produced by corneal thickness and therefore provides a more accurate IOP reading compared to the reference tonometer (Goldmann prism), based upon the correction value table for Goldmann tonometer prism | Device: Goldmann Tonometer prism<br>* IOP tonometer prism for assessment of intraocular pressure<br>|
| Active Comparator: CATS tonometer<br>determine if the CATS tonometer prism effectively reduces sensitivity to IOP errors produced by corneal thickness and therefore provides a more accurate IOP reading compared to the reference tonometer (Goldmann prism), based upon the correction value table for Goldmann tonometer prism | Device: CATS tonometer prism<br>* IOP tonometer prism for assessment of intraocular pressure<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| All subjects will have CATS tonometer prism intraocular pressure readings compared to Goldmann tonometer prism readings. |  | From date of randomization until 24 hours | 
| All subjects will have corneal thickness measurements performed and the CATS tonometer prism intraocular pressure readings will be compared to Goldmann tonometer readings using a correction value table. |  | From date of randomization until 24 hours |