Department for Uvea & Vitreo – Retina
This department deals with disorders of the back portion of the eye.
If we consider the eye to be a hollow sphere ,then, the transparent jelly which fills the inside of this sphere is the “VITREOUS”, & the light sensitive tissue which lines the back of this sphere is the “RETINA”.
The retina is like the film of a camera , on which the image is formed & then sent to the brain.
The “uvea” is the coloured part of the eye & forms the middle layer of the eye. This layer is extremely rich in blood supply.
Commonly diagnosed & treated uveal and retinal disorders are:-
Vitreous
1 Vitreous haemorrhage
2 Endophthalmitis
Retina(Medical)
1 Diabetic retinopathy
2 Age related macular degeneration
3 Laser photocoagulation
4 FFA & ICG
Retina (Surgical)
1 Retinal detachment
2 Epiretinal membrane
3 Macular hole
4 Diabetic vitrectomy
Uvea
1.Anterior Uveitis,
(including HLA- B27 iridocyclitis)
2.Posterior uveitis
(including VKH syndrome, choroiditis and
infectious pathologies such as toxoplasmosis,toxocariosis & tuberculosis.)
The diagnosis and management of Vitreo retinal diseases need various hi tech instruments.
At BCEIRC, the Vitreo Retinal department is equipped with the latest state of the art instruments which include:-
- Topcon digital fundus camera with FFA & ICG attachments & the “IMAGENET” software for data management.
- CarlZeiss Stratus OCT III ,a machine which uses the principle of laser interferometry to give transverse scans of the retina with resolution of upto I0 microns. The images are likened to an in-vivo histopathological cross-section.
- Alcon ultrasonography machine (B-scan), for sonography in eyes with opaque media, to aid diagnosis and management.
- Iridex Green laser with laser indirect and slit lamp adapters for laser photocoagulation, which is used in the treatment of various retinal disorders such as retinal holes, diabetic retinopathy, diabetic maculopathy,amongst others.
Vitreoretinal surgeries are complex in nature, as the retina is a very delicate structure. At BCEIRC, we have a dedicated Vitreoretinal operating theatre, which is well equipped with all requisite surgical instruments & machines which are needed in the surgical management of these complex vitreoretinal disorders. They include
- .Zeiss operating Microscope
- Oertli fully loaded Vitrectomy machine with high speed cutters and small gauge (23 G & 25 G) compatibility.
- Binocular indirect opthalmo microscope (BIOM) to enable, wide field fundus view during intraocular surgeries.
- Cryotheraphy machine.
- Iridex red laser ( 810 nm) for intra operative laser photocoagulation.
Age Related Macular Degeneration
Age related macular degeneration (ARMD) is the leading cause of registered blindness in people over 50 years worldwide. Approximately 25-30 million people are affected by some form of ARMD. This number is expected to triple over the next 25 years.
ARMD is a degenerative disease of the retina that causes progressive loss of central vision, leaving only the side vision intact.
Types of ARMD:
It is the more common and milder form of ARMD. It results in gradual loss of vision and may or may not eventually develop into the wet form.
Although the wet form of ARMD is less common, the chance for severe and rapid loss of vision is much greater. In wet ARMD abnormal vessels under the macula leak fluid and blood into the tissue. This eventually leads to scarring and a permanent loss of central vision.
Symptoms of Macular Degeneration are:
• Loss of central vision
• Lines may appear wavy and faces may appear blurred
• Difficulty in distinguishing colour
• Dark spaces that block the central vision
While ARMD rarely causes total blindness, the loss of central vision may make everyday activities extremely difficult.
In either form of ARMD, once retinal tissue is damaged, lost vision cannot be regained.
RISK FACTORS FOR ARMD:
The exact cause is unknown. The only clinically proven risk factor is smoking. Several studies have identified possible additional risk factors like age, genetics, hypertension, sun exposure, farsightedness, light skin or eye color.
Several studies have found that family history of ARMD increases the risk of developing the disease. Therefore, if you have ARMD, it is even more crucial that your children should regularly schedule eye examinations for ARMD, after 40 years of age
Is ARMD treatable?
There is currently no treatment for dry ARMD. Vitamins, minerals and antioxidants may have a role in preventing the progression of macular degeneration.
There are various clinically proven treatments for wet ARMD :
Laser Photocoagulation seals the abnormal blood vessels. However, this procedure produces a blind spot in the vision.
Transpupillary Thermo Therapy (TTT) is no longer popular due to its ineffectivity.
Surgery is rarely used now due to availability of safer and more effective alternatives.
Photodynamic Therapy is a treatment that uses a non-thermal (or cold) laser without leaving a blind spot in the vision.
Intravitreal Anti-VEGF (Vascular Endothelial Growth Factor) drugs have recently been found to be effective. However, since the action lasts for a short duration, repeat treatments may be needed.
At times, a combination of two or more treatments may be used.
Importantly, all these treatments are aimed not primarily to improve vision but to reduce further vision loss. Hence, early diagnosis is the key to effective treatment because once vision is lost, it cannot be regained.
Newer more effective and longer-lasting therapies are under investigation. Experimental approaches like Retinal transplantation are still new and will require years of clinical research to determine their safety and effectiveness.
How can I avoid losing vision due to ARMD?
• Regular Eye Examination: A chart called the Amsler Grid may also be used in some cases to highlight visual distortions symptomatic of ARMD.
• Quit Smoking
• Control High Blood Pressure
• Protect Your Eyes from Ultraviolet (UV) Light
• Eat a Healthy Diet rich in fruits and dark green leafy vegetables and low in saturated fat
• Exercise Regularly
What are the rehabilitation options available for ARMD patients?
Vision rehabilitation options such as low vision aids (e.g., strong reading or telescopic lenses, electronic devices, etc.), support services, talking books (available at your local public library) and learning activities of daily living are available.
Early diagnosis through medical eye examinations at least every year offers eye care specialists the opportunity to provide appropriate options for possible
MYOPIA
Myopia is a condition in which a person needs “minus” power spectacles, to focus light rays on the retina and provide accurate vision .Myopia of 6 dioptres and above is called pathological myopia. Myopia in general and pathological myopia specifically,warrants regular retinal examination to look forassociated conditions like retinal holes/tears and/or weak spots. These, if present, may need to be prophylactically treated( strengthened )with laser photocoagulation to reduce the risk of complications like retinal detachment.
RETINAL DETACHMENT
Retinal detachment occurs when a hole (tear) or weak spots in the retina ( pre- existing or acquired) , cause the retina to separate from the back of the eye. This condition requires immediate / early surgery. The operation can either be done without entering the vitreous cavity (scleral buckling) or with intra ocular procedures (vitrectomy), depending on the type of retinal detachment. Any person who experiences floaters (black spots), sees flashes of light or visualizes a curtain/shadow in any part of his/her field of vision, should undergo a thorough retinal examination immediately in order to rule out a retinal tear and/or retinal detachment.
Diabetic Retinopathy
Diabetes is a disease that occurs when the body does not secrete enough insulin or is unable to utilize it properly. Insulin is a hormone that regulates the level of sugar (glucose) in the blood. Diabetes can affect children and adults.
Diabetes causes an excessive amount of glucose to remain in the blood stream which may cause damage to the blood vessels. Within the eye the damaged vessels may leak blood and fluid into the surrounding tissues and cause vision problems.
Causes of vision loss in diabetic retinopathy:
1. Diabetic Maculopathy
In diabetic macular edema, fluid rich in fat and cholesterol leaks out of damaged vessels and accumulates in the macula. This is the most common cause of visual loss in diabetics. In macular ischemia, blood supply to this crucial zone is affected and often causes permanent drop in vision which may not respond to laser.
2. Vitreous hemorrhage (bleeding)
Diabetes leads to formation of new vessels in the retina. The fragile new vessels may bleed into the vitreous, which is a clear, gel-like substance that fills the center of the eye. If the vitreous hemorrhage is small, a person might see only a few black spots called “floaters”. A very large hemorrhage might block out all vision.
3. Retinal detachment:
The fibrous (scar) tissue associated with the new blood vessels can shrink, wrinkling and pulling the retina from its normal position. Macular wrinkling can cause visual distortion. More severe vision loss can occur if the macula or large areas of the retina are detached.
4. Neovascular glaucoma:
Occasionally, extensive retinal vessel closure will cause new, abnormal blood vessels to grow on the iris (colored part of the eye) and block the normal flow of fluid out of the eye. Pressure in the eye builds up, resulting in neovascular glaucoma, a severe eye disease that causes damage to the optic nerve.
TREATMENT
The best treatment is to prevent the development of retinopathy as much as possible. Strict control of
your blood sugar will significantly reduce the long-term risk of vision loss from diabetic retinopathy.
If high blood pressure and kidney problems are present, they need to be treated.
Laser
In presence of macular edema, the laser is focused on the damaged retina near the macula to decrease the fluid leakage. The main goal of treatment is to prevent further loss of vision or in other words to stabilize existing vision.
Laser treatment may also be needed for all other parts of the retina except the macula. This treatment causes the abnormal fragile new vessels to shrink and often prevents them from growing in the future.
It also decreases the chance that vitreous bleeding or retinal distortion will occur.
Multiple laser treatments over time are sometimes necessary. Laser surgery does not cure diabetic retinopathy and does not always prevent further loss of vision.
Surgery (Vitrectomy)
Vitrectomy is a surgery commonly needed for diabetic patients who suffer a vitreous hemorrhage or retinal detachment. During vitrectomy, the retinal surgeon carefully removes blood and vitreous from the eye, and reattaches the retina to the back of the eye. The prognosis for visual recovery is dependent on the severity and duration of the detachment. Laser treatment and silicone oil injection in the eye may be needed.
NEWER TREATMENT MODALITIES
Intravitreal injections are given in the vitreous jelly of the eye to reduce diabetic macular edema. While steroids have been used for this purpose they may increase the eye pressure. Newer anti-VEGF injection (Avastin, Macugen, Lucentis) are also being used now with lesser side-effects and promising results.
The injection procedure itself takes seconds and it usually feels like a tiny prick. You can go home later on the same day … this is a 'day care' procedure
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