Posted: 03/07/2018
A retinal detachment associated with a retinal tear is a serious ophthalmic condition. It is often a medical emergency and, if not treated quickly (or correctly), can lead to permanent visual loss or even complete blindness.
The retina is a light sensitive layer that lines 65% of the back of the eye, composed of photosensitive (light sensitive) cells called rods and cones. The macula, which forms part of the retina, is a small area in the centre of the retina that processes sharp, clear vision. When light rays are focused through the cornea, pupil and lens, the retina converts the light energy into signals that are carried by the optic nerve to the brain and interpreted as the images that we see. A healthy, intact, retina is fundamental to clear vision.
The retina is not actually attached to the vascular choroid layer that sits directly behind it, but is held in place by the pressure of the vitreous humour, often known simply as the ‘vitreous’. This is a clear gel-like substance that fills the space between the eye’s lens and retina. Its function is to ensure the eye keeps its shape, to allow light to pass through the eye and focus on the retina, and to keep the retina firmly in place.
As we get older, it is not uncommon for the vitreous to shrink. When this happens, it may detach from the retina, which is often a harmless condition known as a posterior vitreous detachment (PVD). A PVD can cause a patient to experience symptoms such as flashing and floaters, which are caused by the vitreous pulling on the retina as they detach from one another.
In more serious cases, the pull of the vitreous on the retina causes the retina to ‘detach’ from the back of the eye, leaving a space behind it, known as a retinal detachment. The symptoms of this are very similar to those of PVD, and patients may experience flashes and floaters in their vision. They may also experience a dark curtain, which can move up, down or across their vision, caused by the retina folding over on itself as it detaches from the back of the eye.
Sometimes, when the vitreous pulls on the retina and detaches, it can cause the retina to tear and the vitreous fluid to pass through the tear into the back of the eye. This in turn will increase the rate of detachment.
If a patient experiences symptoms of flashing, floaters and/or a dark curtain moving across their vision, they should attend their optician or doctor as quickly as possible. These symptoms can be a sign of both serious and less serious eye conditions, so it is essential to obtain a diagnosis quickly.
An optician should dilate the patient’s pupils to check for an obvious detachment. If the detachment is not obvious, then a slit lamp examination should take place to check whether the vitreous has detached from the retina, if the retina has detached, or if there could be a more serious underlying condition. The optician should then check all the peripheries of the eye and look for signs of ‘tobacco dust’, ie cells in the vitreous, and a clear indication that there has been a tear in the retina.
If the optician is satisfied that there has been only a PVD, and nothing more sinister, then it is acceptable for the patient to be reassured that the symptoms caused by the PVD are likely to resolve on their own over time. However, the patient should be advised to monitor their symptoms and if they worsen, or change, then they should return to the optician or doctor as quickly as possible.
If the patient has experienced a retinal detachment (with or without an associated tear), then treatment is required quickly to reattach the retina. If this does not happen and the retina continues to detach, it may lead to a full detachment of the macula, known as ‘macula-off retinal detachment’, in which case the visual prognosis is often much worse.
Retinal detachment and retinal tears are treated by specialist ophthalmic surgeons. A detached retina can be treated during a procedure known as a vitrectomy where the ophthalmic surgeon removes the vitreous from the eye and replaces it with a special type of gas or a silicone oil. Both of these substances act to re-pressurise the eye and push the retina back into its natural position. If there is an associated tear with the detached retina, the surgeon will need to close the tear using either a laser, cryotherapy or by applying a buckle around the outside of the eye. The pressure of the buckle applied on top of the tear will force it to close.
The prognosis of a detached retina, if treated quickly, is usually good. Problems and complications can occur, however, if there are delays in diagnosis and/or in the patient’s treatment. If, at diagnosis, the macula is still attached, then treatment for a ‘macula-on retinal detachment’ should take place within 24 hours of the onset of symptoms. If it does not take place within this timescale, the macula is more likely to have detached by the time it is treated. Scar tissue will also likely have built up within the eye and visual prognosis will be worse.
If the macula is detached at the time of diagnosis, the patient will be diagnosed with a ‘macula-off retinal detachment’. Visual prognosis from that point is not as good and, as there is less time-pressure to reattach the retina (as the macula is already detached), treatment should take place within seven days of the onset of symptoms.
Arran Macleod, an associate in the clinical negligence team at Penningtons Manches LLP, comments: “Conditions that affect eyesight are, understandably, very worrying for patients. In many cases treatment is time-critical in order to achieve a good outcome and prognosis. Patients, should, therefore, attend their optician or doctor as soon as they experience visual symptoms.
“Regrettably, even if a patient does attend their doctor straight away, we see many clinical negligence claims arising from poor management of their condition; whether it involves misdiagnosis of a PVD rather than retinal detachment, or delays in referring patients for time-critical treatment. Where misdiagnoses or delays occur, the prognosis and outcome of the patient’s eyesight is often worse than it should have been.
“If you, a member of your family or a friend have any concerns about the management of your retinal detachment, a member of our specialist ophthalmic team would be happy to discuss this further with you and to assess whether you may have a claim for compensation.”
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