Plain English Summary
Background and study aims
The cornea is the transparent front part of the eye. Disorders of the cornea can result in scarring and a loss of transparency leading to loss of vision (corneal opacification). This is a significant cause of blindness in the UK and remains the second most common cause of blindness in the developing world. Recent innovations in corneal transplant techniques (endothelial keratoplasty) have shown significant benefit to patients. The donor cornea can be prepared using two techniques, either by hand or by using a machine to cut away the cornea. To date, there have been no satisfactory studies comparing the two methods. The aim of this study is to compare the methods using a randomised controlled trial.
Who can participate?
Patients aged 18 years or above with visual compromise due to loss of corneal transparency.
What does the study involve?
Patients will be allocated to one or the other surgical technique and outcomes will be closely observed over the course of 1 year that would involve 6 follow up visits. The follow up visits are the same frequency for all corneal transplant patients even if they are not part of a clinical trial.
What are the possible benefits and risks of participating?
Benefits: Contribution to scientific evidence on best treatment options for patients with corneal failure and regular follow-ups with the research team to monitor progress following corneal transplant procedure for patients.
There are no particular risks related to taking part in the trial. The clinical risks are the same for all patients undergoing corneal transplantation such as rejection, infection, failure and repeat procedures.
Where is the study run from?
Cambridge University Hospitals NHS Trust, UK
When is the study starting and how long is it expected to run for?
October 2016 to April 2020
Who is funding the study?
1. Cambridge University Hospitals, UK
2. Fight for Sight UK
Who is the main contact?
Prof Madhavan Rajan
V1200616, IRAS 201097
Microthin Descemets Stripping Automated Endothelial Keratoplasty (Microthin-DSAEK) vs
Descemets Membrane Endothelial Keratoplasty (DMEK) - RCT
DMEK surgery results in better visual outcomes compared to Microthin DSAEK in patients with corneal endothelial decompensation
Approved 02/08/2016, London - Fulham Research Ethics Committee (Barlow House, 3rd Floor, 4 Minshull Street, Manchester, M1 3DZ, UK; +44 (0)207 1048165; firstname.lastname@example.org), ref: 16/LO/1343
Single centre interventional double blind randomized clinical trial
Primary study design
Secondary study design
Randomised parallel trial
Patient information sheet
Not available in web format, please use contact details to request a participant information sheet
Corneal endothelial failure
1. All patients eligible for the trial will be randomised either to the DMEK arm or MT-DSAEK (Micro thin DSAEK) arm.
2. Randomisation: One eye per patient will be randomised to either undergo MT –DSAEK or DMEK base on a paper based randomisation process led by the clinical trials unit, with an independent statistician preparing the concealment /randomisation list and sealed envelope preparation. We calculated that 28 patients in each arm will give at least 80% power to detect a 0.1 logarithm of the minimum angle of resolution (logMAR) difference (around 1 line difference or 5 letters)
3. The trial will be a double blind trial:
3.1. Patients will be unaware of what arm they are randomised to
3.2. Technicians taking measurements will be unaware of what arm patients are randomised to
3.3. Analysis of data will be conducted by an independent clinical physician who has no involvement in the care the patients
3.4. Only surgeons supervising the care of the patients will be able to see which arm the patient had been randomised to and this included the operating surgeon
In Microthin DSAEK the endothelial transplant is prepared from the cadaveric human donor cornea using a mechanised microkeratome with transplant thickness varying between 70-130 microns. The DSAEK endothelial transplant consists of a monolayer of endothelial cells on the descemets membrane with posterior stromal layer. By regulating the corneal donor thickness using a stromal dehydration technique we have shown a reliable way to create an endothelial transplant thickness of 100microns with minimal variance, termed microthin DSAEK. This technique will be compared to DMEK in this trial.
In this procedure the endothelial transplant is prepared by manual peeling of the descemets membrane, which consists of a monolayer of endothelial cells without the posterior corneal stroma measuring 15-20 microns in thickness.
Both transplants (MT-DSAEK and DMEK) are delivered to the eye using a sterile disposable surgical injecting instrument. And the attachment of the transplant to the host cornea is assisted with an air bubble in the anterior chamber.
Patients will be followed up 1 week, 1 month, 3 months, 6 months, 9 months and 12 months following the surgical procedure.
Primary outcome measure
Best corrected visual acuity measured using LogMar values at 12 months
Secondary outcome measures
1. Visual Acuity: An optician trained in the use of ETDRS charts will check the autorefractive reading and then will measure BCVA at 3, 6 and 9 months
2. Refractive cylinder: Results will be taken with an autorefractometer 3 times or until till a consistent reading will be obtained. The last 3 results will be averaged. Refraction will be then checked manually by a trained optician when BCVA will be measured
3. Central corneal thickness: Central corneal thickness will be measured by anterior OCT. This will be performed by an experienced trained technician with all scans independently verified by a doctor not involved with the care of the patients
4. Endothelial cell density: The cell density (cells/mm²) will be measured using specular microscopy at 6 and 12 months
5. Patient functional questionnaire: Patients will be asked to fill out a standard visual function questionnaire at each time point (VF 14) – there are 14 questions related to visual function and collected at 6 and 12 months
6. Complications: Rate of intraoperative and post-operative complications will be analysed between the two groups
Overall trial start date
Overall trial end date
Reason abandoned (if study stopped)
Participant inclusion criteria
1. Visual compromise due to corneal endothelial decompensation
2. Aged 18 years or above
Target number of participants
Participant exclusion criteria
Patients with several ocular comorbidities in addition to corneal endothelial decompensation will be excluded
Recruitment start date
Recruitment end date
Countries of recruitment
Trial participating centre
Cambridge University Hospitals NHS Trust
Cambridge University Hospitals
Funding Body Type
private sector organisation
Funding Body Subtype
For-profit companies (industry)
Fight for Sight UK
Funding Body Type
private sector organisation
Funding Body Subtype
Trusts, charities, foundations (both publically funded and privately funded)
Results and Publications
Publication and dissemination plan
Planned publication in a high-impact peer-reviewed journal.
IPD sharing statement:
The datasets generated during and/or analysed during the current study are available from the corresponding author on reasonable request. Prof. Madhavan Rajan, Consultant Ophthalmic Surgeon, Box 41, Addenbrooke’s Hospital, Hills Road, Cambridge, CB2 0QQ. The data sharing plans are not defined and will be made available at a later date. However, the CI can take any enquiries for request in the mean time.
Intention to publish date
Participant level data
Available on request
Basic results (scientific)
- ISRCTN10578843_PROTOCOL_V1_20June16.pdf Uploaded 10/01/2020