What will happen at the study visits?
Before surgery, you will have the NHS pre-operative appointment where a full eye examination and detailed measurements of your eyes will be carried out, just as for any routine cataract operation.
This will be followed by appropriate NHS follow up visits as standard of NHS care, as well as by the study-specific visits as follows.
1-Week Follow-Up Visit
About one week after each eye surgery, a standardised photograph of the front of your eye (the anterior segment) will be taken. This scan helps the study team confirm that the new lens implant is stable and correctly positioned.
The procedure is quick and completely non-contact. You will sit comfortably in front of the camera, resting your chin on a support—just like in a routine eye examination. The imaging itself takes less than five minutes, and the entire visit is expected to last around 30 minutes.
1- and 3-Month Follow-Up Visits
At approximately one and three months after surgery, you will have a complete eye examination in both eyes to assess your visual outcomes.
All tests are non-invasive. They are carried out with your head resting gently on a chin support while seated in front of the equipment—exactly as in a normal eye examination. Each visit will last around two and a half hours and will include:
Conventional sight testing with letter charts with targets at different distances.
Refraction, which measures any residual spectacle correction.
Binocular defocus curve testing to check how well you can see at a range of distances.
Contrast sensitivity testing to check on the ability of the visual system to differentiate objects from their background especially in low light leveles.
Photographs of the front and back of the eye, taken with specialised cameras that assess the eye’s structures. These images are completely non-invasive and painless.
Questionnaires about your vision and quality of life. You will be asked to complete questionnaires, which together take about 30 minutes in total. These are well-validated tools used in vision research to help us understand how surgery affects your everyday visual experience:
The Vision Correction Questionnaire (VCQ) looks at how your eyesight and any visual symptoms affect your daily activities, such as reading, driving, and using screens.
The Intraocular Lens Satisfaction Questionnaire (IOLSAT) asks about your satisfaction with your sight after surgery, including how independent you feel from glasses for different tasks.
The Quality of Vision Questionnaire (QUVID) focuses on the clarity and comfort of your vision, and whether you notice visual effects such as glare, halos, or blur in certain lighting conditions.
Some questions may seem repetitive or may not apply to you - this is normal. You can skip any question you do not wish to answer, and this will not affect your care in any way. Your answers will remain confidential and will only be used for research purposes.
After the three-month follow-up visit, no further study assessments will be required.
What will I have to do?
If you choose to take part in this study, you will be expected to:
Answer some background questions about yourself, including your age, general health, and eye history.
Attend all your study appointments. If you think you may need to miss or reschedule a visit, please contact the study team as soon as possible so that a new date can be arranged.
Inform the study doctor about any changes in your health or vision during the study. This includes symptoms such as blurred or double vision, glare or halos, discomfort, or pain in the eyes, as well as any new medications or hospital visits. Even if you are unsure whether a change is related to the study, please let us know so we can monitor your safety and collect accurate information.
Complete a few questionnaires about your vision and quality of life at the scheduled visits.
Let the study doctor know if you are considering joining another research study at the same time.
Will I receive reimbursement?
You will not be paid for taking part in this study. As per NHS standards, all medication, tests and medical care required as part of the study will be provided to you free of charge.
You can claim a contribution to your travel expenses for study visits only. We will be able to offer £10 contribution towards your travel expenses per each research visit at the clinical research facilities if you request it.
Will my General Practitioner be notified?
The study doctor will inform your GP that you are taking part in this study and may ask them to provide relevant medical information about you, if necessary.
What other choices are there?
You do not have to take part in this study to receive treatment or care. This decision will not have any impact for you and your decision will not affect your relationship with your doctor or hospital.
If you decide not to participate in this study, your study doctor will provide and explain to you the standard care that is usually given, as detailed in the Moorfields Eye Hospital Information Sheet on Cataract.
Multifocal intraocular lens in bilateral cataract surgery is the G-PERFECT study. The study is sponsored by Moorfields Eye Hospital NHS Foundation Trust and funded by Alcon Eye Care UK Limited.
