What are the possible risks of taking part?
There are no additional cataract surgical risks from taking part in this study beyond those that apply to any patient having cataract surgery.
Cataract surgery is a safe and commonly performed procedure. However, as with any operation, complications can occasionally occur. Serious complications are rare.
The main risks are:
1 in 1,000 risk of severe and permanent visual loss in each eye.
Around 1 in 250,000 risk of severe and permanent loss of vision in both eyes when both are treated on the same day (Immediate Sequential Bilateral Cataract Surgery). This is an extremely rare event.
About 1 in 100 operations may require additional surgery to rectify a problem for each eye.
About 1 in 20 operations have less serious complications, which may require further treatment at the time of surgery or following the operation for each eye.
About 1 in 10 patients may need laser treatment in the future to clear a thin membrane that can form behind the lens implant (a normal, treatable change called posterior capsule opacification).
You will be given the standard Moorfields Eye Hospital cataract information and consent form to read and discuss well in advance of your operation. This form includes detailed explanations of all potential risks and will help you make an informed decision.
Multifocal lenses, such as the study lenses, can provide good vision at several distances but may cause some visual side effects.
Some people notice halos, glare, or starbursts around lights—particularly when driving at night or in dim lighting (dysphotopsia).
Vision in low-contrast or dim environments may appear slightly softer or less sharp. This is due to a small reduction in contrast sensitivity, which means that edges and fine details may be a little less distinct in low light.
Even though the goal is to reduce dependence on glasses, a small proportion of patients still need glasses in some circumstances
These visual side effects are mild and tolerable for most patients and tend to become less noticeable as the brain adapts to the new lenses over time.
The ideal candidate for multifocal lenses is a subject:
Motivated not to wear glasses full time;
Not a professional driver and not depending on night driving.
Who fully understands that despite best efforts glasses may still be required for specific tasks.
Able to adapt to any visual side effect, if any.
Concerning study visits, there are no side effects expected from the tests, photographs or scans taken of your eyes. These are standard, painless, non-invasive testing and imaging procedures used routinely in eye clinics around the world. You may feel a brief flash of light from the camera, but this is harmless.
It is important you understand the functionality of these multi focal lenses. If you are unsure about any of these risks or side effects, please ask your study doctor or a member of the research team—they will be happy to explain them in more detail.
Any medical problems or side effects that occur during the study will be reviewed by the study doctor and recorded according to research regulations. Serious or unexpected events will be reported promptly to the study sponsor (Moorfields Eye Hospital NHS Foundation Trust) and to the Research Ethics Committee, in line with national research governance requirements.
The study team regularly reviews all safety information to identify any new risks. If important new information arises that might influence your decision to continue in the study, you will be informed straight away.
After surgery
If you notice any of the problems listed below, or if you are worried about your eye for any reason, you must contact or attend the clinic where you had your surgery or go to the Accident & Emergency Department at Moorfields Eye Hospital (City Road), which is open 24/7 for eye emergencies only. Please follow the NHS instructions for any negative event.
If that is not possible, please see your GP as soon as possible.
Increasing redness, pain, blurring of vision, or yellow/green discharge
this may be a sign of a serious infection or inflammation.
Blurring of the central vision – this may indicate fluid collecting in the centre of the retina (macular oedema).
If after stopping the drops the eye becomes red, sore, with or without light intolerance– this can be caused by inflammation coming back inside the eye.
Distorted vision – rarely, the lens implant can move from its original position and may need further surgery to be repositioned.
Shadow, flashing lights, or new floaters in your vision – this can sometimes happen after lens surgery. A temporary ‘half-moon’ or ‘crescent’ shadow at the edge of your vision can occur and often settles as the eye adapts to the new lens (called negative dysphotopsia). A growing shadow with increasing floaters or flashing lights can be a sign of a retinal detachment, which needs urgent attention.
If in doubt, contact the hospital immediately.
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.
