Your eye contains a lens to focus light on the retina at the back of the eye. This is similar to a camera where a lens within the camera focusses light on the film or sensor at the back of the camera. Early in life the lens is clear but over time it becomes cloudy; rarely an injury to the eye or some medications can speed the process, but usually the clouding is purely due to time and exposure to UV light.
What are the benefits of surgery?
During cataract surgery a replacement lens is inserted into the eye; the strength and type of lens can be varied to suit you and potentially reduce or eliminate the need for glasses. Of note some of the lens options only work well in specific situations (eg absence of other pathologies within eye and regular corneal curvature). I will be pleased to assess this and further advise re the options available.
Over 95% of cataract operations proceed without any significant problems during or after the surgery, leading to a meaningful improvement in vision.
What happens if I don't have surgery?
Without surgery cataracts thicken leading to worsening vision. For most cataracts the deterioration is slow over years, but some forms progress more quickly. As the cataract progresses you will also need to change your glasses more frequently. Cataracts do not however damage the eye, and so when to have surgery is ordinarily purely decided by your symptoms – ie how much it troubles you. With modern machines the density /“ripeness” of a cataract is no longer relevant in deciding whether to have surgery or not.
On the day of surgery
Most cataract operations are performed under local anaesthetic, in which case you can eat and drink as normal prior to surgery. Any regular medications should also be taken as normal. Within the hour before surgery drops or a pellet is used to dilate the pupil within the eye. During the surgery it will not be necessary to lie totally flat. The skin around the eye will be thoroughly cleaned and a sterile drape applied over the eye to be operated on. This is lifted up over your nose and mouth so that you can breath normally. A small clip is used to keep your eyelid open; due to the anaesthetic you are unlikely to notice this or that you are not blinking as normal. The operation should not be painful though some pressure can be felt at certain stages (eg lens insertion); I will be talking to you during the procedure and in the presence of discomfort (which is uncommon) more anaesthetic will be applied. At the end of the operation a patch or shield is usually placed over the eye. This is because initially following surgery you will need to avoid any pressure on the eye. However this protection only need be worn for the first night following surgery.
What are the risks of surgery?
Unfortunately all operations have risks. The benefit versus risk ratio is extremely favourable for cataract surgery compared to other operations. Nonetheless, although the problems that can occur are uncommon they can have lasting effects as discussed below.
Infection - This occurs after approximately 1 in 1000 cataract operations but is a sight threatening complication. Urgent attention should be sought after the operation if the eye became painful, if the vision started to deteriorate or if there was increased swelling around the eye; early treatment of an infection improves the outcomes.
Retinal Detachment is a sight threatening problem that is usually treatable with further surgery. The risk is approximately 1 in 140 within 5 years following the surgery but is increased in people with high myopia having surgery before their 60s. Symptoms to look out for are a sudden increase in the number of floaters, worsening flashing lights, or a shadow in the peripheral vision. Again early treatment improves outcomes and so prompt attention should be sought in the event of such symptoms.
Bleeding within the eye at the time of surgery can also be sight threatening but is extremely uncommon (3 in 10000).
Damage to lens capsule - The replacement lens implant is ordinarily inserted within a natural bag (referred to as a capsule) within the eye to hold it in place. Damage to this structure can require a 2nd operation to address and fully remove the cataract. For most people the risk of this is less than 1 in 100 operations, though it is sometimes apparent before the surgery that the risk is increased. This will be discussed with you in advance if this is the case.
Inflammation - A degree of inflammation is inevitable after surgery and so you will be prescribed steroid eye drops following the surgery. These are usually only required for 3-4 weeks but sometimes they can be required for longer. Inflammation within the other eye as well, potentially threatening the sight in both eyes, is extremely rare at less than 1 in 1 million and is usually treatable.
Cystoid Macula Oedema - This is swelling within the retina following surgery reducing the vision. It is more common in the presence of diabetic retinopathy but can occur to anyone with a rate of approximately 1 in 50. It is usually treatable but can require a prolonged course of eye drops or even a steroid injection.
In the days following surgery
The vision is commonly blurring for 1-2 days following the surgery depending on the density of the cataract. The eye mayfeel scratchy but should not be significantly painful. Any redness will usually settle within days. You will have eye drops to apply 4 times a day following the surgery; you will need to have clean hands to do this. It is important not to get any dirt into the eye or knock it but infact you will be able to walk around and perform many activities immediately afterwards. I recommend avoiding strenuous exercise until after the first post-operative check, and avoiding swimming until after you have finished the course of post operative steroid eye drops (3-4 weeks usually).
Within the first week following surgery you should avoid getting water in the eye.
The visual requirements for driving a private car include being able to read a number plate from 20 metres away. You should also not have any double vision and must have an adequate field of vision. Many people infact reach this level within days of the surgery but not all. If in doubt, or troubled by imbalance between the two eyes, I recommend waiting until the post-operative clinic visit and discussing further with me then.
This is best left until 5-6 weeks following the surgery to ensure the wounds are fully healed and the prescription stable.