Retinal Conditions
The eye is one of the most important organs in the body and the retina receives information about everything you see such as colours, shapes and movements. Thousands of times each day, the eyes move and focus on images near and far, providing detailed 3-Dimensional pictures of the world around us. The eyes help accumulate a lifetime of memories in a visual form, making it a gift that is unlike any other. Retina disorders can affect the way that you process visual information and lead to distorted or absent vision.
Age Related Macular Degeneration
Age related macular degeneration more commonly known as AMD or ARMD results in the degeneration of the macula causing central vision reduction. The macula is located in the central retina and allows for fine detailed vision. Macular degeneration patients will notice blind spots in their central vision, which may lead to distortion in the vision. The patients will also experience a reduction in their colour vision, difficulty in recognizing faces and an overall reduction in vision. The risk of AMD increases as age increases. Macular Degeneration is either classified as dry or wet. The dry form of macular degeneration is by far more common than the wet however the wet form usually leads to more severe vision loss.
- Dry AMD – approximately 90% of people with AMD have dry macular degeneration. Patient’s with dry macular degeneration present with slowly deteriorating vision.
- Wet AMD – approximately 10% of people with AMD have wet macular degeneration.
It is quite possible for dry AMD to become wet AMD suddenly. Patients need to see an ophthalmologist immediately if there is loss of vision in either eye.
Who is at Risk:
There are certain factors that predispose patients to developing macular degeneration. Patients with blue or green eyes and familial history of macular degeneration have a higher risk, Caucasian people are far more at risk. The following factors also increase ones risk of developing macular degeneration namely; smoking, obesity, diabetes, cardiovascular disease and poor diet (diet poor in antioxidants such as spinach).
Investigations to Detect Macular Degeneration:
A variety of tests may be conducted to detect Macular Degeneration. Ophthalmologists will examine the patients visual acuity and conduct a dilated funduscopy. An Amsler grid will also be performed in each eye to determine if there is noticeable distortion of lines. An optical coherence tomography (OCT) will be conducted to examine the retinal layers and provide full thickness retinal maps. The OCT allows ophthalmologists to compare the patients retinal layers against a normative database and monitor the progression of Macular Degeneration. Some patients may need to undergo a fluorescein angiogram which indicates leakages and abnormal vessels by injecting Fluorescite (dye) into the patients arm. The various tests needed to diagnose AMD are all available at Sandhurst Eye Centre, as are doctors who have a special interest in this field.
Treatment:
Current research indicates that patients can prolong the onset of macular degeneration by good nutrition (Green leafy vegetables), nutritional supplements (please speak to your ophthalmologist about this), well controlled cholesterol, a reduction in UV radiation exposure, smoking and alcohol.
Unfortunately there is no cure for macular degeneration however measures can be taken to prevent the progression. Anti –VEGF (vascular endothelial growth factor) is the latest in wet AMD treatment. Anti – VEGF drugs namely Avastin and Lucentis are injected into the retina on a regular basis to prevent leaking.
Retinal Tear
The vitreous is a transparent gel located between the lens and the retina. The vitreous constitutes between 66 – 75% of the globe. Retinal tears occur when the vitreous pulls away from the retina resulting in a tear in the retina. People at risk are those who are myopic or short sighted. Eye injuries and previous surgery are also risk factors. Seeing flashing lights and floaters are ominous signs. In order to prevent a retinal detachment, see your ophthalmologist soon after these symptoms occur.
Retinal Detachment
A retinal detachment is a medical emergency occurring when the sensory retina separates from the retinal pigment epithelium. It often arises after a retinal hole appears.
Retinal detachments are divided into 2 types, namely: rhegmatogenous retinal detachment and non rhegmatogenous retinal detachment. Rhegmatogenous retinal detachment occurs due to retinal breaks. Non – rhegmatogenous retinal detachments are either tractional or exudative.
The following symptoms may be observed; reduction of vision, floaters and flashes of light. Retinal detachments may occur as a result of a posterior vitreous detachment.
Retinal detachments are treated by means of surgery, usually the kind of surgery involving working inside the back of the eye. A pars plana vitrectomy entails the surgical removal of the vitreous from the eye and replacing with silicone oil or gas. Patients may be advised not to travel in airplanes for up to 6 weeks after retinal surgery is performed.
Macular Hole
The macular is a region on the retina providing central vision and fine details. As this region is thin and avascular it is susceptible to developing a hole. Macular holes can occur after trauma and in people who are short sighted (myopic).
