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Cataract Surgery – Should I Have Both Eyes Done Together?
Cataract surgery is the most commonly performed operation worldwide and has evolved to a fantastically precise and successful operation. There is continuous innovation and even in the last decade, there has been enormous change. For example, artificial intelligence is being used to select the lenses used, surgical incisions have got smaller, entire new classes of intra-ocular lenses have been developed, phacoemulsification machines and settings have evolved and microscope optics are better than ever.
These changes have all added together to make cataract surgery more safe and precise than ever before. After a time, when enough of these small changes come together, the paradigm for this surgery in turn can change. In the past, patients were told that the cataract has to be ‘ripe’ in order to have the surgery. This was entirely subjective and there is no objective way of quantifying when the lens was ‘ripe’ and indeed, what the ophthalmologist can see looking at the lens is different to what the patient can see looking through a lens. What the ophthalmologist was saying was that the surgery carries a risk and it is wise to do surgery when the benefit clearly outweighs the risk.
Today, to correct a refractive error, we often do a clear lens exchange, whereby the clear lens is replaced with an artificial lens. This is effectively the same procedure as cataract surgery whereby the lens is removed and replaced with an artificial lens. This is often done to correct short sightedness (myopia) or long-sightedness (hypermetropia). In the case of clear lens extraction, there is no cataract at all. It is because of all of the changes that have made the surgery so safe and predictable, that we can perform this surgery at such an early stage.
Prior to the COVID pandemic, it was the norm to operate for cataracts b on one eye at a time, usually starting with the worst of the two. This allows one eye to settle before further surgery, and for the patient to complete the customary four weeks of postoperative eye drops that are usually prescribed. The risks of surgery are either during the procedure and after the procedure. The postoperative risks in the eye include macular oedema or swelling in the retina (5%), needing further surgery either due to a fragment of lens falling into the back of the eye or inability to place the lens (1%), and loss of vision (0.1% or 1 in 1000). Usually by four weeks, we would know if any of these problems had developed and would therefore deal with them before undertaking surgery to the fellow eye. Added to this is the fact that when we perform cataract surgery, we aim for a visual target, usually good unaided (without glasses) distance vision. In about 5-10% of patient, the eye settles with a more myopic or hypermetropic refraction (glasses prescription). In such cases, performing surgery at separate visits, usually at least 4 weeks apart, can help as an adjustment can be made or the tests can be repeated to help minimise any inaccuracy.
During the COVID pandemic, it was deemed safer for cataract surgery to operate on both eyes at the same time than to have multiple hospital visits. Based on this experience and the excellent results, there was a trend towards performing bilateral immediately sequential cataract surgery (ISBCS) i.e. both eyes at the same time. Certainly, it is more convenient to have both eyes operated at the same time as is reduces the number of visits and waiting around in hospitals and outpatient clinics.
In some cases, such as if one is very myopic or hypermetropic, there can be an imbalance (anisometropia) between the two eyes if there is a gap. This can cause a magnification difference which can be difficult to tolerate, but which settles after the second eye is operated. In this case, ISBCS can be advantageous as this anisometropia can be annoying for the period of time between the first and second eye surgery.
On the other hand, if the eye is myopic or hypermetropic eyes preoperatively, cataract surgery can be more complex, with a higher risk of complications such as retinal detachment risk in myopic patients, and for this reason, there is an argument for doing these eyes separately. Postoperatively, with ISBCS, if the eyes settle to be more long or short sighted than expected, an adjustment cannot be made for the lens in the second eye.
Additionally, operating on the two eyes at the same visit does not allow a period of time to check that there are no postoperative complications and the worry is that problems may develop postoperatively in both eyes together. The biggest worry, that of bilateral sight loss postoperatively, is quoted at around 1 in 500,000 cases.
Based on the experience of surgeons across the world, ISBCS is increasingly being adopted. Mr Modi performs surgery for cataracts both separately and as ISBCS usually after discussion with the patient so that a joint decision is made. There is no right or wrong way to have cataract surgery and each case depends on the baseline characteristics of the eyes, patient preference and a joint evaluation of risks/benefits.
In particular, Mr Modi stresses the importance of preoperative and postoperative measures to improve outcomes from cataract surgery. Preoperatively, the main factor that can be modified is that of blepharitis. Treatment of blepharitis can reduce the risk of infection postoperatively. Postoperatively, it is a case of keeping the eye clean and dry. Avoiding things like gardening or getting anything in the eye, particularly in the first two weeks postoperatively. Remembering the eye drops and putting these in properly is also important. Finally, it is important to get back in touch with your surgeon if there is a problem – prompt review and treatment of problems can turn around a potential problem completely.
There are many other individual factors when considering whether to have cataract surgery performed one eye at a time or both eyes together. If you have any questions, then please don’t hesitate to ask or get in touch.