RETINAL DISEASES
Diabetic Retinopathy
Diabetes mellitus is a condition which affects millions of Indians. It impairs the body’s ability to use and store sugar. Elevated blood sugar levels and excessive thirst and urination are the indicators of diabetes. It can affect vision by causing damage to the blood vessels of the retina, or a higher incidence of cataract and glaucoma. Changes are also seen in blood vessels all over the body.
What is Diabetic Retinopathy ?
It is an advanced stage of the diabetic disease process in which the blood vessels in the retina are damaged and leak fluid or blood. The longer a person has diabetes, the more the risk of developing diabetic retinopathy. People with type I diabetes [diabetes since childhood] are more likely to develop diabetic retinopathy at a younger age.
What are the symptoms of Diabetic Retinopathy ?
Early diabetic retinopathy usually has no symptoms. Gradual blurring of vision may occur if fluid leaks in the central part of the retina called diabetic macular edema. In late diabetic retinopathy, new abnormal blood vessels begin growing on the surface of the retina or the optic nerve. These vessels have weak walls and leak blood out into the retina and vitreous [jelly that fills most of the eye]. Presence of blood in the path of light entering the eye blocks vision.
How is Diabetic Retinopathy Diagnosed ?
A complete eye examination is required for the detection of diabetic retinopathy. We perform a painless examination of the retina of the eye using an instrument called the indirect ophthalmoscope after dilating the pupils. If diabetic retinopathy is found, a special test called fluoresce in angiography may be performed where a dye is injected in the vein and photographs of the retina are taken.
How is Diabetic Retinopathy Treated ?
In early cases only regular follow-up may be necessary. More advanced cases require treatment to control the damage of diabetic retinopathy and improve sight.
- Laser photocoagulation involves the focusing of a powerful beam of laser light on the damaged retina to seal leaking retinal blood vessels and stop abnormal blood vessel [neovascularization] growth.
- Intravitreal Injections: Are excellent options with very good results for cases which do not respond to laser or are not amenable to laser. The drugs used are triamcinolne acetonide (steroid),avastin,lucentis,macugen.
- Surgery -Vitrectomy – In the event of the patient presenting with very advanced diabetic retinopathy, a microsurgical procedure known as vitrectomy is recommended. Blood-filled vitreous gel of the eye is replaced with a clear solution to aid in restoring vision. Sometimes the retina may also be detached. Vitrectomy surgery is then performed to reattach the retina.
- Recent Advances – 23G and 25G Vitrectomy is a suture less retinal surgery where the post operative recovery is fast. We are one of the pioneers in this system.
- Our Vitrectomy system “Alcon Accuress 3D with X D platform” with a BIOM viewing system is the most advanced system in the world.
- Our surgeon Dr Hitendra Mehta is higly experienced in these modern surgeries and is one of the earliest surgeons in India performing sutureless vitreo Retinal surgeries since 2004. (since its inception)
How to prevent visual loss in Diabetes ?
Prevention of diabetic retinopathy and accompanying visual loss is a team effort involving the patient and our team of diabetic eye specialists. Early detection of diabetic retinopathy is the best protection against loss of vision. Diabetics must have their retinas examined at least once a year. Our diabetic clinic is designed towards providing regular preventive care as well as follow-up for patients with established diabetic retinopathy.
It is very important that the patient metabolic factors are kept under control for effective treatment of his eye condition.
Age-Related Macular Degeneration:
What is the Macula ?
The macula is a small area at the center of the retina that allows us to see fine details such as central vision, activities such as reading and writing and appreciating colour vision.
What causes Macular Degeneration?
Sometimes the delicate cells of the macula are damaged and stop functioning. The exact cause is not known although it tends to happen as people get older. This is called age-related macular degeneration.
The most common types of macular degeneration are dry and wet.
The dry type is caused by aging and thinning of the tissues of the macula. The wet type results from the formation of abnormal blood vessels under the macula which leak fluid or blood and blur the central vision. Children and young people can also suffer from an inherited form of macular degeneration called macular dystrophy, which can sometimes affect several members from the same family
Symptoms of macular degeneration:
- Blurred or distorted central vision
- Colours look dim
- Words on a page look blurred
- Straight lines appear distorted
- Dark or empty areas appear in the center of vision
This makes activities like reading, writing and recognizing small objects or faces very difficult
How is Macular Degeneration Diagnosed ?
- Detail ophthalmic examination especially of the retina.
- Fundus Fluoresce in Angiography ( FFA ) to find abnormal blood vessels under the macula.
- Optical Coherence Tomography ( OCT )
How is Macular Degeneration Treated ?
The dry form is treated by focusing on helping the person improve his central vision using low-vision aids like magnifying glasses, telescopic spectacles or closed-circuit televisions.
Avastin / Lucentis / Macugen -Pathbreaking treatment for ARMD
In wet ARMD, since there are leakages which have to be sealed, it needs to be treated.
Earlier the recommendation was ARGON laser treatment or PDT (Photodynamic therapy) which did not give desired results. Now the recent treatment is with anti-VEGF factors like Injection Avastin / Lucentis.
Anti-VEGF drugs block the trouble-causing VEGF, reducing the growth of abnormal blood vessels and slowing their leakage.
The recent development of anti-VEGF medications have become a path breaking advance in the treatment of wet AMD.
- Bevacizumab (Avastin) and Ranibizumab (Lucentis) and Macugen (Pegagtanib) are very useful drugs. Most patients will retain the vision they have and some will regain some of the lost vision after these treatments. These injection have to be injected in the eye
- Injection Lucentis (approved by US FDA) is injected as one injection every month for three months is the total dose. Then re evaluated after 3 months.
- Injection Avastin is an injection which is used world wide with good results but is not approved by US FDA but is the same drug as Lucentis.
- The above doses generally take care of the acute need of treatment and no further injections are required, unless the condition changes over time.
- Photodyanamic Therapy: Is a “cold Laser” which is done after injecting a dye called visudyne intravenously. The patient has to stay in dark room for 72 hours after the procedure. It is done in combination with intravitreal injections.
- Home Monitering: Regular monitoring of your central vision at home with an Amsler grid will help us detect progression in the early stages. Any abnormality or its progression must immediately be reported.
Retinal Vein Occlusions
Introduction to Retinal Circulation and their obstructions:
Retina – the main part of visual sensation has got numerous blood supplies through retinal vessels. “Retinal arteries” bring the blood from heart to the retina while “Retinal veins” drain the blood from the retina towards the heart. There is one main Central Retinal Artery (CRA) and one main Central retinal veins (CRV). They give origin to numerous branches.
There may be an obstruction to the blood flow in retinal veins – either branched or central. These are one of the common causes of vascular problems in retina. Because of this obstruction, blood drainage from retina to heart is hampered. “Branch Retinal Vein Occlusion??? or BRVO denotes obstruction of this blood flow in small branches of retinal veins while “Central Retinal Vein Occlusion” or CRVO denotes obstruction of blood flow in the main and large vein of the retina.
Common Causes:
- Increased blood pressure, which is not in proper control or fluctuating control.
- High intra ocular pressure – what we call as glaucoma.
- In many patients, the cause is not known. What we call as Idiopathic.
- There are many other uncommon causes.
Mechanics of Obstruction:
In the retina, arteries and veins cross at many locations. In case of high blood pressure, arteries become rigid and hard and they cause pressure over the soft veins at the point of crossing, so blood flow from these veins is obstructed.
Similarly, if the pressure inside the eyeball is increased (as in glaucoma), the soft veins of the retina will be compressed and blood flow from the vein is hampered.
What symptoms will patient get?
- If the occlusion is in the periphery of the retina (as in BRVO), the symptoms can just be a blackish or hazy vision in one corner of the field.
- If BRVO involves the Macula or the center of the retina then the patient will have sudden drop in vision and will have a black shadow in his main or central part of the field.
- In CRVO the patient could have a variety of visual loss ranging from mild visual disturbance to sudden drop or loss of vision depending upon the type of CRVO.
- In BRVO, if only a small portion of peripheral retina is involved then it may not give any symptoms.
Management of these cases:
These patients need to be examined by a retinal surgeon and detailed examination has to be done to find the cause and to see if any changes have occurred. In some cases, Fundus Fluoresce in Angiography (FFA) may be necessary to know the site of obstruction or leakage and if any other changes have occurred.
Patient may develop macular edema that is fluid collection in the macula (central part of the retina).
After few months, some may develop new vessels on the retina or on the iris as a response to the less blood or oxygen to the retina which may lead to serious complications like vitreous hemorrhage, retinal detachment, rubeosis iridis or secondary glaucoma.
Treatment:
Laser:
In the form of focal laser or Panretinal laser for macular edema or new blood vessels due to CRVO or BRVO
Intravitreal injections:
The options are triamcinolone acetonide, lucentis,avastin, macugen. The results are excellent in most cases.
Surgery:
For patients who have vitreous hemorrhage and tractional detachment.
Recent Advances – 23G and 25G Vitrectomy is a suture less retinal surgery where the post operative recovery is fast. We are one of the pioneers in this system.
Our Vitrectomy system “Alcon Accuress 3D with X D platform” with a BIOM viewing system is the most advanced system in the world.
Our surgeon Dr Hitendra Mehta is highly experienced in these modern surgeries and is one of the earliest surgeons in India performing suture less vitreous Retinal surgeries since 2004 (since its inception)
Floaters
What is it ?
Floaters are seeing of flying black particles in front of the eye. Typically they appear as some mosquitoes flying in front of the eye. They are usually visible in moderate light and not seen in very dark light. They may vary in number and may occasionally disappear.
Why floaters develop ?
Floaters are because of some particles in the jelly of the eye called vitreous. Certain other condition like high myopia (near sightedness), ageing and vitreous detachment may give rise to floaters. Rarely, serious eye diseases like retinal holes, vitreous hemorrhage etc. may also give rise to floaters.
What is its importance ?
In some cases it could be an early symptom of serious eye disease.
What to do if you see floaters
Your eyes should be examined in detail at least once, because you may have a retinal problem. Majority of patients don’t need any treatment except follow-ups. Very rarely there may be a retinal hole or vitreous hemorrhage and you may need to undergo treatment for that.
Advice to the patient seeing floaters: ( After eye checkup )
- Try to ignore them. They will settle down with passage of time.
- Keep the track of number of floaters. If the number suddenly increases or their shape drastically alters, then consult your eye surgeon immediately.
Flashes of light
What is it ?
It is a symptom in which patient sees flashes of light in some portion of his visual field. Flashes are seen more commonly in dark as in late evening, night or in early morning.
What is its importance?
Flashes are premonitory symptom of impending or early retinal detachment. Retinal detachment is one of the serious diseases of the eye. It is important to consult your eye surgeon if you notice flashes.
Rarely, it could be because of certain changes in vitreous (liquid of eye) condensation. But again, this vitreous condensation may also lead to retinal detachment.
So, every patient complaining of flashes should be examined on the urgent bases because there could be retinal detachment.
Why these flashes are seen ?
These flashes of light are seen because of movements and stretching of the retina during detachment which gives some sensations to the retinal receptors and give rise to the sensation of flashes.
What to do if you see flashes ?
Immediately consult your eye surgeon to find out the cause of flashes. If retinal detachment has occurred, it may need to be repaired surgically. If not, regular follow up is necessary to check if retinal detachment develops later.
Retinal Detachment
- What is retinal detachment ?
- What are the symptoms of retinal detachment ?
- What are the different types of retinal detachment ?
- Who is at risk for retinal detachment ?
- How is retinal detachment treated ?
- National Eye Institute-Supported Research
What is retinal detachment ?
The retina is the light-sensitive layer of tissue that lines the inside of the eye and sends visual messages through the optic nerve to the brain. When the retina detaches, it is lifted or pulled from its normal position. If not promptly treated, retinal detachment can cause permanent vision loss.
In some cases there may be small areas of the retina that are torn. These areas, called retinal tears or retinal breaks, can lead to retinal detachment.
What is retinal detachment?
Symptoms include a sudden or gradual increase in the number of floaters and/or light flashes in the eye or the appearance of a curtain over the field of vision. A retinal detachment is a medical emergency. Anyone experiencing the symptoms of a retinal detachment should see an eye care professional immediately.
What are the different types of retinal detachment ?
There are three different types of retinal detachment:
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Rhegmatogenous – A tear or break in the retina causes it to separate from the retinal pigment epithelium (RPE), the pigmented cell layer that nourishes the retina, and fill with fluid. These types of retinal detachments are the most common.
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Tractional – In this type of detachment, scar tissue on the retina’s surface contracts and causes it to separate from the RPE. This type of detachment is less common.
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Exudative – Frequently caused by retinal diseases, including inflammatory disorders and injury/trauma to the eye. In this type, fluid leaks into the area underneath the retina (subretina).
Who is at risk for retinal detachment ?
Although anyone can experience a retinal detachment, people with certain eye conditions are at increased risk. Some examples of these conditions include posterior vitreous detachment, lattice degeneration, x-linked retinoschisis, degenerative myopia, and uveitis. Injuries to the eye or head can also cause retinal detachment.
How is retinal detachment treated ?
Small holes and tears are treated with laser surgery or a freeze treatment called cryopexy. These procedures are usually performed in the doctor’s office. During laser surgery tiny burns are made around the hole to “weld” the retina back to into place. Cryopexy is a similar procedure that freezes the area around the hole.
In some cases a scleral buckle, a tiny synthetic band, is attached to the outside of the eyeball to gently push the wall of the eye against the detached retina. If necessary, a vitrectomy may also be performed to treat more severe cases. During a vitrectomy, the doctor makes a tiny incision in the sclera (white of the eye). Next, a small instrument is placed into the eye to remove the vitreous.
Three such tiny openings (less than 1mm) are placed on the eye and the complex surgery is performed through micro surgical instruments with the most advanced Vitrectomy machine called Accures from Alcon (USA). The retina is flattened with a heavy liquid called PFCL. The retina is attached with laser and the vitreous is replaced with Silicon Oil or Gas (SF6 or C3F8)
Early treatment can usually improve the visual acuity of most patients with retinal detachment. Some patients, however, will need more than one procedure to repair the damage.