Retinal Surgeries – Vitrectomy for Floaters, Epiretinal Membrane & Macula Hole
The centre of the eye is filled with a vitreous jelly that is a mixture of water and protein; early in life the jelly is perfectly clear but over time some of the protein within it comes out of solution, and is seen as lumps of protein or floaters that move within the field of vision. Most floaters therefore accumulate as part of the normal ageing process of the eye. They can also develop in association with retinal tears or inflammation within the eye, and so a prompt ophthalmic examination is required if there is a sudden increase in the number of floaters. Floaters ordinarily remain long-term. For many people they become less noticeable and troublesome with time. This is not the case for everyone though. In addition, they usually remain visible in certain lighting conditions, notably when there is a bright background. Most people with floaters can still read small text and have good vision, albeit with the intermittent disturbances caused by the floaters. As long as there is not an underlying cause for the floaters then then the vision is not under threat from the floaters. If the number of floaters increases however, it is advisable to have another ophthalmic check in case there is a reason for that.
Epiretinal Membrane and Macula Holes
Epiretinal membranes and macula holes are two problems that can affect the macula, the central area of retina responsible for colour and high resolution vision. An epiretinal membrane is a layer of scarring on the surface of the retina where as a macula hole is a full thickness defect in the retina and gap in the light sensitive photoreceptors. Both conditions cause reduced and potentially distorted central vision, and are most likely to progress in time without treatment. Both are more common with age; epiretinal membranes can also develop secondary to other pathologies within the retina and so the initial assessment will involve dilated fundoscopy looking for any other retinal conditions affecting the eye.
Vitrectomy surgery is an highly effective and commonly performed procedure. With surgeries to remove floaters the vitreous jelly is removed and balanced salt solution left in situ to match the normal fluid within the eye.
When performed for epiretinal membranes, the vitrectomy procedure is followed by careful removal of the membrane from the macula. Fine forceps are used to lift the membrane away from the retina without affecting the central macula; once the membrane is removed the retina typically gradually settles with vision improving in the months after.
For macula hole surgeries the vitrectomy is followed by removal of a thinner membrane over the macula known as the inner limiting membrane. A gas bubble is then placed within the eye as this aids healing and closure of the edges of the hole. Such gas bubbles are slowly absorbed from the eye over a number of weeks; until the bubble is absorbed you must not fly or have general anaesthetic involving nitrous oxide (ie it is important to warn your anaesthetist is having another procedure in the weeks following the eye procedure). Face down posturing is rarely needed nowadays.
On the day of surgery
Most vitrectomy surgeries are performed under local anaesthetic with or without intravenous sedation. General anaesthetic is also readily available however for when preferred or more appropriate.
You will be asked to attend the hospital at least one hour before the surgery so that preparatory eye drops can be given..
During the surgery you will be asked to lie flat on your back. 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 eyelids 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; If you are having the procedure under local anaesthetic I will be talking to you and checking you are comfortable.
At the end of the operation a patch is placed over the eye for the first night only; once the anaesthetic has worn off the patch can be removed; there will be some initial redness but this usually settles in a small number of days.
What are the risks of surgery?
Unfortunately all operations have risks. The benefit versus risk ratio is extremely favourable for vitrectomy surgery. Nonetheless, although the problems that can occur are uncommon they can have lasting effects as discussed below.
Infection - This occurs after less than 1 in 1000 such surgeries but is a sight threatening complication. Urgent attention should be sought after the operation if the eye becomes painful, if the vision starts to deteriorate or if there is increased swelling around the eye; early treatment of an infection improves the outcomes.
Retinal Detachment - This 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 10,000).
Cataract - If you have not had cataract surgery previously then the surgery for floaters can hasten the development of cataract in that eye; sometimes a combined lens extraction and vitrectomy procedure is offered to try and avoid successive surgeries.If you have already had cataract surgery then that can make the surgery for floaters more straight forward.
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 - Any surgery within the eye can cause swelling of the central retina, which can reduce central 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, or longer if a gas bubble has been used. The eye may feel scratchy but should not be significantly painful. 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. Many people infact reach this level within days of the surgery but it could take weeks if a gas bubble has been required. 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 at least 5-6 weeks following the surgery to ensure the wounds are fully healed and the prescription stable.