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.

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. 

Early diabetic retinopathy usually has no symptoms.  Gradual blurring of vision may occur if fluid leaks in the central part of the retina [the macula].  In late diabetic retinopathy [proliferative stage], 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.

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 fluorescein angiography may be performed where a dye is injected in the vein and photographs of the retina are taken.

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.   

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.

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 atleast once a year.  Our diabetic clinic is designed towards providing regular preventive care as well as follow-up for patients with established diabetic retinopathy.

The Diabetic Clinic
Our centres run Diabetic Clinics for the special purpose of preserving sight in sight-threatening conditions such as diabetic retinopathy

1. The patient receives specialized care provided by our diabetic retina specialists
2. Diabetes needs regular follow-up since the condition can lead to a dramatic loss of vision if poorly treated or neglected
3. Various factors govern the rate of progression of your condition. It is therefore necessary to review your eye condition periodically even after the present condition has been treated.
4. At each visit to the clinic, we check your vision, intraocular pressure, do a slit-lamp biomicroscopy and perform a detailed retinal examination with dilated pupils using an Indirect Ophthalmoscope. We record images on the advanced Visupac system and maintain records of your eye condition for comparison on following visits. We also monitor factors that control the progression of your eye condition such as diet, blood sugar levels, exercise, blood pressure etc.
5. Perform special procedures like Fluorescein Angiography and Ultrasosography if required.

The retina is a nerve layer at the back of the eye that senses light and sends images to the brain. 

What is a retinal detachment?

The retina is attached to the inner back surface of the eye. Detachment is the pulling away of the retina from its normal position.  The separation of the retina from the wall of the eye impairs its normal functioning, resulting in blurred vision. 

The vitreous is a clear gel that fills most of the space in the eye. It is located in front of the retina.  With age, the vitreous pulls away from its attachments to the retina, usually without causing problems.  Sometimes the vitreous pulls hard enough to tear the retina.  Fluid may then pass through the retinal tear and lift the retina off the wall  of the eye. 

Risk factors for retinal detachment:
Myopia or near-sightedness
Injury to the eye
Previous retinal detachment in the other eye
Family history of retinal detachment
Areas of thin/weak retina 
Complicated cataract surgery

Warning symptoms of retinal detachment
Flashes of light
New, or increase in, floaters [black dots in your vision]
A gray curtain noticed in the field of vision

The retina is examined with an instrument called the indirect ophthalmoscope after dilating the pupil.  Holes and tears are carefully looked for in the periphery of the retina. 

Treatment

Retinal tears without detachment - Laser photocoagulation or cryotherapy is performed around the tear to seal the retina to the back wall of the eye. 
 
Retinal tears with retinal detachment – Requires surgery as soon as possible to put the retina back in its proper position.  The longer the retina stays detached, the less the visual improvement after surgery.  Scleral buckle surgery – A flexible silicone band is placed around the eye to counter the force pulling on the retina after removing the fluid under the detached retina. 

Vitrectomy – The vitreous gel pulling the retina is removed from the eye and replaced with a special gas or silicone oil.

Visual recovery

The more severe the retinal detachment and the longer its duration, the less is the visual improvement after surgery.  For this reason it is very important to see an ophthalmologist at the first sign of any trouble.  If the condition is left untreated it results in loss of useful vision.

AGE-RELATED MACULAR DEGENERATION

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. 

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 the dry [atrophic] and the wet [exudative].

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.

Viewing the maculas with dilated pupils.
Fluorescein angiography to find abnormal blood vessels under the macula. Indocyanine green angiography is done in certain cases.

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. 
The wet form is treated with laser photocoagulation to seal the leaking blood vessels that damage the macula. A special type of dye laser is also used wherever indicated.

Research into macular degeneration
There is a great deal of research done by us and elsewhere that is looking into the causes of macular degeneration and how it can be treated.

The Macula Clinic
Our centres run Macula Clinics for the special purpose of preserving sight in sight-threatening conditions such as age-related macular degeneration

1. The patient receives specialized care provided by our Macula specialists
2. Macular conditions need regular follow-up since the condition can lead to irreversible loss of vision if poorly treated or neglected
3. At the Macula clinic we record images on the advanced Visupac system and maintain records of your eye condition for comparison on following visits.
4. The Clinic employs the latest technologies in the treatment of macular conditions such as photodynamic therapy and has even started using the very popular injection for improving vision with ‘Avastine’, which has excellent results in this condition.

Your role in the management of your eye condition

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.

FLASHES AND FLOATERS

Can flashes and floaters cause total blindness?

If one eye develops flashes or floaters will the other develop them as well?

What are floaters?

Floaters appear as gray or black specks, lines, or "cobwebs", worms, rings or dots in front of the eyes. As the eyes move, the floaters also move. They do not follow your eye movements precisely, as they usually drift when the eyes start or stop moving.
Floaters are caused by clumping of pre-existing vitreous fibers in the eye or bits of material suspended in the vitreous jelly that fills the back of the eye. These floaters are harmless and either settle down in some time or one gets used to it.
The floaters cast shadows on the light sensitive retina. It is actually the shadow of the floater that you see. Floaters may have a variety of causes, some serious, and some not serious at all. Some floaters are red blood cells or blood clots on the surface of the retina or floating in the vitreous. Such blood cells may occur with some retinal tears but do not necessarily indicate a tear. Occasionally, the vitreous can pull on a blood vessel on the surface of the retina and cause bleeding without causing a tear of the retina. Vascular disorders such as diabetic retinopathy and vein occlusion frequently result in bleeding inside the eye.
Rarely, floaters may be inflammatory in origin. Diseases such as pars planitis and uveitis can cause the formation of clumps of white blood cells (cells that the body produces when there is inflammation). Hence, it is best to seek an ophthalmologists opinion in case one sees floaters to rule out any retinal associated problem.

What are flashes?

Flashes are sensations of light, when no light is really there. They may appear as many tiny bright lights (like "sparklers") or like flashes of lightning.

Flashes occur when the vitreous jelly pulls on or tears the retina. These flashes usually last for only a second or so, but typically occur repeatedly. They may be more obvious with eye movement or in a dark room.
Some people with migraine headaches may experience a different type of flash. These are usually shimmering, jagged lights that are present constantly for a period of ten-fifteen minutes or so. They typically appear in the center of your field of vision, and progress slowly towards the edges of the visual field. A headache that is commonly throbbing, and on one side of the head, may follow the disappearance of the flashes.

Low blood pressure can cause people to see stars or specks of light, particularly if they change position quickly. An example would be standing quickly from a sitting position or rising quickly after stooping or bending over. Pregnancy related high blood pressure (pre-eclampsia) could also cause light flashes.

Are floaters and flashes serious?

Many people have floaters. This happens in over 70% of the population as part of the normal aging process. Floaters that you have had for years, and that show little change, are usually not serious. It is the sudden onset of one or more new floaters that may be serious. The onset of flashes may also be serious.

Anyone with flashes or the sudden onset of a new floater (or floaters) needs a dilated fundus examination (looking at the vitreous and retina with specialized equipment after putting drops to enlarge the pupils).

Can flashes and floaters cause total blindness?

No. Floaters cause only a slight blockage of the vision at worst and are usually not detectable by visual testing unless they are very severe.

Importantly, floaters can be related to retinal detachment or a variety of vascular conditions such as diabetic retinopathy, while flashes can be related to retinal tears (breaks) or detachment. These can result in blindness if not treated.

If one eye develops flashes or floaters will the other develop them as well?

It is very common for the same condition to occur in the second eye. For this reason, and because flashes and floaters are sometimes caused by retinal breaks, both eyes should have a dilated fundus exam as soon as possible when flashes or floaters develop in either eye.