Retinal Conditions
Retinal detachments are very serious conditions that require urgent intervention to rescue and preserve vision. This occurs when a hole or tear develops in the retina, allowing fluid to accumulate in the space under the retina.
Symptoms that you may present with include floaters, flashes of light, or a shadow in part of your vision. If picked up early when it is a retinal tear before becoming a detachment, this can be treated with laser.
Treatment
If it has developed into a retinal detachment, then there are 2 main ways to fix this.
The first way is with a surgery called a vitrectomy, where the vitreous gel is removed from the eye and the responsible tears are identified. The retina is then pushed back in place with a gas bubble and the tears sealed with laser.
The second method is with an external approach from the outside of the eye called scleral buckling, whereby using a silicone band, the wall of the eye is pushed inwards to reattach against the retina. In this method, the breaks are usually sealed with freezing known as cryotherapy.
The retina of the eye is supplied by a large artery called the central retinal artery, and then drained by a central retinal vein.
In certain conditions, either the main artery or vein, or its branches, may become blocked and cause a loss in vision.
Retinal artery occlusions are more uncommon. If the main artery becomes blocked (central retinal artery occlusion), you may suffer severe visual loss. If one of the smaller branches becomes blocked, it is called a branch retinal artery occlusion and you may experience a partial vision loss or in some cases, not even realise it. This is often the result of small clots which are released from other parts of the body.
In either case, this is an emergency and immediate treatment is aimed at limiting the area of retina which is damaged by lack of blood. This may involve using some eyedrops and oral medication and even drawing fluid out of the eye. More importantly, we want to look for a possible source of the clots and will arrange other non ocular tests so as to lower the risk of this happening again.
Retinal vein occlusions can also happen to the main vein (central retinal vein occlusion) or to one of the draining branches (branch retinal vein occlusion).
Risk Factors
Risk factors of retinal vein occlusion include atherosclerosis, diabetes, glaucoma, hypertension (high blood pressure), high cholesterol and age-related vascular disease or blood disorders.
Because the risk of these disorders increases with age, retinal vein occlusion most often affects older people.
Complications
The main complications that arise from retinal vein occlusions are the growth of abnormal, friable new vessels, like those seen in diabetes that was previously described, as well as swelling at the central part of the retina called the macula, called macular edema.
Treatment
After a thorough clinical examination and imaging tests, treatment can involve a combination of laser treatment and injections of anti-vascular endothelial growth factor agents and will depend on the severity of the condition.
A macular hole is a hole that is usually found over the centre of the macula, which is the fovea. There are several risk factors for this kind of hole to develop, including trauma, sun-gazing, and short-sightedness. However, a large proportion of them have no specific cause.
If you have a macular hole, you may experience distortion of central vision, difficulty with reading or seeing fine details.
Treatment
This is treated with a vitrectomy, and peeling the superficial layer of the retina to help relieve the tractional forces which may be contributing to the hole and keeping it open. Usually a bubble of gas is left in the eye after the surgery and this will help in sealing the macular hole.
Epiretinal membrane is also known as macular pucker. It is a thin sheet of fibrous tissue that can develop on the surface of the macular area of the retina.
The macula normally lies flat against the back of the eye, like film lining the back of a camera. When wrinkles, creases or bulges form on the macula, this is known as epiretinal membrane.
Symptoms
Most epiretinal membranes are mild and have little or no effect on the vision.
However, in some cases, the epiretinal membrane may slowly grow and begin to cause mechanical distortion (“wrinkling”) in the macula. This may lead to blurred or distorted vision (metamorphopsia), which may slowly worsen over time.
Treatment
Most epiretinal membrane do not need treatment.
Surgery called a vitrectomy surgery is indicated if the epiretinal membrane is causing distorted vision and a drop in the vision.
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