Cataract Surgery: Understanding the Options
Cataract surgery is performed when a cataract has developed in a person’s natural lens, obscuring their vision. The lens is located within and towards the front of the eye. When we are born, the lens is crystal clear, and allows appropriate focusing of light on the retina for crisp vision. With age, a cataract develops in the lens from cumulative oxidative damage from sunlight and other toxins, causing damage to the proteins and other molecules in the lens that ensure its clarity, resulting in opacity.
Cataract surgery is the most common and arguably the most successful operation globally. Cataract surgery has a very low complication rate, very predictable outcomes and rapid recovery. It is efficient, quick surgery that does not require an overnight stay in hospital or heavy anesthetic. And the impact of cataract surgery is amazing. My patients who have received cataract surgery are generally very pleased with their outcomes, and how their new vision transforms their life and opportunities. I never take for granted the opportunity to help so many people so meaningfully.
If you have cataracts, it is important to understand your options and discuss these with your Ophthalmologist. Before surgery, I take the time to discuss the issues of cataract surgery with my patients, as I believe informed patients make the best decisions, and this leads to the best outcomes for them.
- Intraocular lens options
Cataract surgery involves removing the cataract and inserting an artificial intraocular lens to restore vision to its original crispness and clarity. The technology behind these intraocular lenses has progressed significantly in recent years. This means people following cataract surgery will see even better and rely less on eyeglasses for their various activities. However, it has also led to a dizzying myriad of choices in intraocular lenses, and it is important to address these.
While it is common to achieve glasses independence for distance activities, it is harder to do so for near activities (e.g. reading). This is because most artificial intraocular lenses do not have the same range of vision as our natural lenses did when we were younger; they are best suited for one focal distance, which can either be set for distance, near or something in between.
People are understandably keen to explore options to reduce their dependence on glasses for near activities. There are several options to consider, but it is important to recognize each has their pros and cons, and so it is important to pick the right choice which would suit a person’s individual visual needs and lifestyle.
- Distance focus in both eyes
One common option is to have both eyes focused for distance, so that they see well without glasses for distance activities (e.g. driving, golf) and need a pair of glasses for reading. Many people are happy with this arrangement.
- Near focus in both eyes
Another option is to have both lenses focused for near, so that each eye sees near (e.g. reads) without glasses, but needs glasses for distance. Some people who have been short sighted their whole lives, and are happy wearing glasses for seeing in the distance, like this plan.
- Monovision: one eye for far, one eye for near
A third option is to have one eye focused for distance, and the other eye focused for near: this is known as “monovision”. This sounds strange but actually is very successful for many people. Not everyone is suited to this arrangement, and so it is important to see your Optometrist to trial this arrangement with contact lenses prior to the cataract surgery. While avoiding the inconvenience of taking glasses on and off for reading, it does place more strain on each eye if there is extensive reading or distance viewing – that is why for people who read a lot, or those who desire crisp vision in either eye for distance (e.g. for seeing at the theatre), it may not be suitable. Also – both eyes must be in good working order; if one eye has a problem of the macula, cornea or other issue, then this approach will not work.
- Multifocal intraocular lenses
A fourth option is a multifocal intraocular lens, which offers the opportunity to see distance, intermediate and near simultaneously. That sounds great, but this lens is associated with other problems such as glare, haloes, sparkles around lights and reduced contrast. This might be intolerable for some, but for the right person, these visual problems are insignificant compared the satisfaction of reduced dependence on spectacles for near vision.
- Extended Depth of Focus (EDOF) intraocular lens
A fifth, and probably the best option, is the recently available Extended Depth of Focus (EDOF) intraocular lens. In some ways this is like the traditional multifocal lens: EDOF lenses allow a large range of vision for distance and intermediate activities (but glasses still might be required for very close activities and fine print reading). However, by their clever design they achieve this without all the visual problems of multifocal lenses – they are as well tolerated as regular intraocular lenses.
Finally, it should be noted that all the intraocular lens choices available allow full correction of astigmatism, which is a critical element for great vision and independence from glasses. Astigmatism occurs when the eye refracts (bends) light unequally in one direction versus another; this is often caused by an uneven curve in the cornea. In general, I encourage use of intraocular lenses that correct astigmatism (known as toric lenses). We used to believe there was advantage in leaving people with residual astigmatism, but today more evidence shows this is not the case – people are happiest, and have the greatest functional range of vision, when astigmatism is fully corrected.
- Surgical technique: laser-assisted or no laser?
Like all conventional surgery, modern cataract surgery is performed in a standard operating theatre environment, to maximise sterility and minimise the risk of infection. In cataract surgery, precision surgical instruments are used to make small incisions at the periphery of the cornea (clear window of the eye), and then break up the cataract which is then removed by ultrasound.
About 15 years ago there was a lot of excitement and enthusiasm about a new technique known as excimer laser for cataract surgery. The supporters of this technique believed it would lead to more accurate and predictable vision outcomes following cataract surgery. Some people were misinformed and believed this would mean no need for surgery, instead cataracts could be performed as an outpatient laser technique.
The excimer laser involves using precisely applied laser to perform some of the functions of the surgical instruments: namely making the initial corneal incisions, and breaking un the cataract before removal by ultrasound. In this way the laser does not replace in-theatre surgery, but does replace a few of the steps performed in the operating theatre. Practically, this is achieved by first performing the laser steps in one room with the excimer laser, and then moving the patient to a standard operating theatre to complete the surgery.
The jury is still out as to whether the excimer laser improves any outcomes of cataract surgery. After the initial hype it was difficult to demonstrate scientifically any clear benefit. In some ways the excimer created new problems and potential complications, although much of this was related to the learning curve that occurs whenever surgeons adopt a new technique.
As a cataract surgeon I am frequently asked by patients about laser cataract surgery, mainly because they believe that this will avoid a trip to theatre. Once I inform them this will not be the case, that the laser does not replace the work in theatre they are less enthusiastic. In general I do not encourage excimer laser-assisted cataract surgery; I find that unnecessary steps lead only to extra costs and potential extra complications, and I like to keep processes as smooth and as simple as possible. In fairness, I know of many cataract surgeons whom I respect that use the excimer routinely. It is important for patients to be aware of their options, and to discuss these openly with their surgeon.
- Anesthetic technique: general, topical or regional anesthesia
One of the great advances of modern cataract surgery is designing the procedure to be performed with only the lightest of anesthetics. This has many advantages. The operation is quicker, safer and gentler with lighter anesthetics than heavier ones. For instance, general anesthesia (in which patients are put to sleep), the heaviest form of anesthesia, has several risks for patients, and is a stress on the heart and lungs. Lighter anesthesia means we can offer cataract surgery to many patients considered too old or frail for other operations that require general anesthesia.
Compared to general anesthesia, the other lighter options (topical and regional anesthesia) are performed while you are awake, but sedated and relaxed. In topical anesthesia, we numb the eye with local anesthetic drops, but you still can move your eye, and have to keep it still by looking ahead at the microscope light for the 10-15 minute duration of the operation. However, in many cases it is preferable to have the eye completely immobilized as well as numb – this is achieved by regional anesthesia, in which the eye is numbed and immobilized by an injection of local anesthetic behind it, administered by an anesthetist. You are briefly sedated by the anesthetist for the injection and so it is not uncomfortable, but you are still awake for the cataract surgery.
In general, we encourage you to have the surgery while awake, but sedated and relaxed. This is the safest choice for you. The experience is not unpleasant – you are given a relaxing medicine and can listen to the friendly chatter in theatre and our great music selection. Because of the anesthetic you won’t feel any pain; on the rare occasion where you feel pain, you can let us know and we will give extra numbing medicine to ensure you are completely comfortable. Despite this, some patients are still very insistent on being put to sleep (general anesthesia) for their operation, and of course this is an option we can provide. Speak to our surgical and anesthetic teams – it is important to have these conversations prior to surgery to ensure the experience is as smooth and pleasant for you as possible.
- Combining cataract surgery with other procedures for glaucoma
Some patients have both cataract and other eye health conditions – such as glaucoma. As a glaucoma and cataract specialist I am frequently managing patients with both glaucoma and cataract. A common option in this scenario is to use a minimally invasive glaucoma stent at the time of cataract surgery to help with intraocular pressure control. These are tiny titanium stents inserted into the eye’s drainage pathways (trabecular meshwork). The stents I use have a great safety profile with proven efficacy – I am proud to have contributed to the international literature documenting this.
For some people with more advanced or aggressive glaucoma, the minimally invasive glaucoma stents are not enough to control the intraocular pressure – in this case we need a larger glaucoma operation; one commonly used option is a trabeculectomy. In a trabeculectomy we create a drainage pathway from inside to outside of the eye. Compared to the microstents, a trabeculectomy results in a lower intraocular pressure, but requires more frequent post operative drops to be administered and more post operative visits to my practice.
If you have both cataracts and glaucoma, it is important to discuss with your surgeon whether it is worthwhile performing a procedure for glaucoma, which one to consider, or whether the better approach is to address the cataract alone. The choices are not always easy, and will depend on several factors, including the severity and type of glaucoma, the desired intraocular pressure reduction, as well as your ability after the surgery to frequently use eyedrops and to attend the clinic for post-operative care.