Determination of corneal biomechanical properties in-vivo using a contact device
| ISRCTN | ISRCTN31552904 |
|---|---|
| DOI | https://doi.org/10.1186/ISRCTN31552904 |
| Clinical Trials Information System (CTIS) | 2014-002712-16 |
| Protocol serial number | UoL000983 |
| Sponsor | University of Liverpool (UK) |
| Funder | Engineering and Physical Sciences Research Council |
- Submission date
- 25/06/2014
- Registration date
- 23/07/2014
- Last edited
- 31/03/2016
- Recruitment status
- Stopped
- Overall study status
- Stopped
- Condition category
- Eye Diseases
Plain English summary of protocol
Background and study aims
This is a research project that has two studies.
Study A
A Goldmann tonometer (GAT) is the standard method used to measure the internal pressure (intraocular pressure) of the eye by pressing the cornea (the transparent dome-shaped window covering the front of the eye) with a small flat piece. The aim of Study A is to develop a new technology to measure the biomechanical (structural and functional) properties of the cornea. Characterising these properties are vital for treating conditions (e.g. diseases or injury) that effect the corneas ability to maintain its shape and its ability to focus light, and therefore effect an persons ability to see. Corneal biomedical properties also affect how some diseases (for example keratoconus, where the shape of the cornea alters to resemble a cone) are treated, the accuracy of intraocular pressure (IOP) measurements, outcome of eye surgery procedures and the design of contact lenses. Since the new device will come into contact with the eye, anaesthetic must be used before measurements are taken. Here, we want to find out how reliable the new device is and how comfortable it is to use. It is similar to a GAT tonometer, but is operated by a computer and uses a curved contact tip. The device will press against the cornea and move it inward and backward by about half of a millimetre. This will be done 3 times using different loading rates.
Study B
The aim of this study is to compare corneal stiffness and hysteresis (elastic and viscoelastic) measurements of the new device compare to those taken by another device called the Ocular Response Analyzer (ORA). The stiffness measurements will also be compared to that taken by a new non-contact device called the Corvis ST. The study will also consider the stability of the measurements when the device and the eye are not accurately aligned.
Who can participate?
The study population will be healthy volunteers and participants with raised intraocular pressure, with or without ocular hypotensive therapy. Patients will be screened against the inclusion and exclusion criteria for the study.
What does the study involve?
Participants recruited to study A will undertake the following assessments:
1. General Medical and Ophthalmic History
2. Visual Acuity Check (standard check of your vision on a letter chart)
3. Biomicroscopy, Ophthalmoscopy, Gonioscopy (standard check of the health of the eye)
4. Corneal stiffness measurements with the device under study using three different loading rates.
5. Biomicroscopy
6. A short questionnaire about comfort during the measurements
Participants recruited to study B will undertake the following assessments:
1. General Medical and Ophthalmic History
2. Visual Acuity Check (standard check of your vision on a letter chart)
3. Biomicroscopy, Ophthalmoscopy, Gonioscopy (standard check of the health of the eye)
4. Eye Pressure measurements with Goldmann applanation tonometer and dynamic contour tonometer.(These are the standard clinical methods of checking the eye pressure during a routine visit to the optometrist or eye doctor. We will need to instil one drop of a mild topical anaesthetic, which will wear off after approximately 20 minutes. You are advised to refrain from rubbing your eye until this time.).
5. Corneal Hysteresis (CH) and Corneal Resistance Factor (CRF) will be measured by the Ocular Response Analyzer (ORA).
6. Corneal force-deformation response measurements using the device.
7. The ophthalmic examination is repeated to search for any adverse effects caused by using the prototype.
What are the possible benefits and risks of participating?
Participants will volunteer to participate in this study which aims to derive the stress-strain behaviour of corneal tissue from the in-vivo stiffness measurements. Quantifying corneal mechanical properties is also important when these properties impact on the treatment of diseases such as keratoconus, accuracy of IOP measurements, improving the outcome of refractive surgery procedures and design of contact lenses.
Where is the study run from?
1. Ninewells Hospital (UK)
2. Moorfields Hospital (UK)
3. Aberdeen Royal Infirmary (UK)
The study is managed by the Liverpool Clinical Trials Unit (UK)
When is the study starting and how long is it expected to run for?
July 2014 to February 2015
Who is funding the study?
Engineering and Physical Sciences Research Council (UK)
Who is the main contact?
Mr M Bickerstaff
oasis@liv.ac.uk
Contact information
Scientific
University of Liverpool
School of Engineering
Brownlow Hill
Liverpool
Liverpool
L69 3GH
United Kingdom
Study information
| Primary study design | Observational |
|---|---|
| Study design | Single-arm study of a non-CE-marked medical device |
| Secondary study design | Other |
| Study type | Participant information sheet |
| Scientific title | Determination of corneal biomechanical properties in-vivo using a contact device: a single-arm, observational study |
| Study acronym | DetCorBio |
| Study objectives | This is an observational study to determine the corneal biomedical properities of patients with high IOP using a novel contact device. The device applies indentation to the participants cornea and monitors the corneal deformation and load to measure the overall stiffness of the cornea. A computer is used to control the device and to store the measurements. The cornea is a load-bearing tissue whose primary function is to focus light on the retina. The mechanical properties of the cornea are important in maintaining this function under the effect of actions such as intraocular pressure (IOP), eyelid movement and external impacts. Characterising the mechanical properties of the cornea is of critical clinical importance when action is to be taken to remedy deterioration in mechanical performance, caused for instance by disease or injury, and leading to corneal failure to maintain its shape and focus light. Quantifying corneal mechanical properties is also important when these properties impact on the treatment of diseases such as keratoconus, accuracy of IOP measurements, outcome of refractive surgery procedures and design of contact lenses |
| Ethics approval(s) | Not provided at registration |
| Health condition(s) or problem(s) studied | Increased intraocular pressure of eye |
| Intervention | The device applies indentation to the participants cornea and monitor the corneal deformation and load to measure the overall stiffness of the cornea. A computer is used to control the device and to store the measurements. |
| Intervention type | Device |
| Phase | Not Applicable |
| Drug / device / biological / vaccine name(s) | |
| Primary outcome measure(s) |
Study B |
| Key secondary outcome measure(s) |
Study A |
| Completion date | 01/02/2015 |
| Reason abandoned (if study stopped) | Lack of funding/sponsorship |
Eligibility
| Participant type(s) | Patient |
|---|---|
| Age group | Adult |
| Lower age limit | 18 Years |
| Sex | All |
| Target sample size at registration | 70 |
| Key inclusion criteria | 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 |
| Key exclusion criteria | 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 |
| Date of first enrolment | 01/07/2014 |
| Date of final enrolment | 01/02/2015 |
Locations
Countries of recruitment
- United Kingdom
- England
Study participating centre
L69 3GH
United Kingdom
Results and Publications
| Individual participant data (IPD) Intention to share | No |
|---|---|
| IPD sharing plan summary | |
| IPD sharing plan |
Study outputs
| Output type | Details | Date created | Date added | Peer reviewed? | Patient-facing? |
|---|---|---|---|---|---|
| Participant information sheet | Participant information sheet | 11/11/2025 | 11/11/2025 | No | Yes |
Editorial Notes
31/03/2016: Because of the long time it was taking to get the clinical trial approved, the trial was abandoned as the funded project reached its end date before the trial was ready to start
