Determination of corneal biomechanical properties in-vivo using a contact device
- Conditions
- Increased intraocular pressure of eyeEye Diseases
- Registration Number
- ISRCTN31552904
- Lead Sponsor
- niversity of Liverpool (UK)
- Brief Summary
Not available
- Detailed Description
Not available
Recruitment & Eligibility
- Status
- Completed
- Sex
- All
- Target Recruitment
- 70
1. At least 18 years of age
2. Normal findings in the medical history unless the investigator considers an abnormality to be clinically irrelevant
3. Normal ophthalmic findings, other than high IOP
4. Astigmatism <2D
5. Potential to complete the study and comply with appropriate instructions
6. Signature on the informed consent form
1. Corneal pathology or previous intra- or extra-ocular surgery, including refractive surgery (e.g., radial keratotomy, photorefractive keratotomy, LASIK, intracorneal ring), retinal surgery (e.g., buckle, photocoagulation), or implantation of a primary or secondary intraocular lens
2. Contact lens wearing within 3 days (rigid contact lenses) or 1 day (soft contact lenses) prior to study day
3. Inability to fully understand the ?informed consent?
4. Participants who are diabetic
Study & Design
- Study Type
- Observational
- Study Design
- Not specified
- Primary Outcome Measures
Name Time Method Study B<br>1. The correlation between the force-displacement measurements made by the device and:<br>1.1. The overall stiffness as estimated mathematically based on the cornea?s thickness, topography and age<br>1.2.The differences in IOP readings made by two devices; namely the Goldmann Applanation Tonometer or GAT (which is known to be affected by corneal stiffness), and the Dynamic Contour Tonometer or DCT (which is known to be much less affected by corneal stiffness than GAT),<br>1.3. Corneal Resistance Factor, CRF (a stiffness-related parameter) as provided by the Ocular Response Analyzer (ORA).<br>1.4. The stiffness estimate provided by Corvis ST; a recently-released and not yet fully validated, non-contact device.<br>2. The correlation between the tissue hysteresis (difference in stress-strain behaviour under loading and unloading conditions) measured by the new device and the Corneal Hysteresis (CH) parameter provided by the Ocular Response Analyzer (ORA)<br>3. Estimation of tissue viscoelasticity
- Secondary Outcome Measures
Name Time Method Study A <br>1. The reliability and repeatability of the device output<br>2. Comfort of use and tolerance of the new device<br>3. Assessment of general operation of device