Globally, 1.1 billion people have a visual impairment that could have been treated or prevented. Eye health is a major public heath challenge in Sri Lanka as well as in globally, particularly in rural areas – primarily due to conditions of cataract, glaucoma and diabetic retinopathy, which can lead to blindness.
Many of us are affected by eye conditions that may impact on our daily life. Early detection and treatment of eye conditions reduces vision impairment and blindness leads to opportunities for education and employment, improves quality of life and reduces poverty.
Browse or search our resources about common and rare eye conditions and diseases. Get the basics or go in depth about symptoms, diagnosis, and treatments
Cataract is still the leading cause of blindness in Sri Lanka. Cataract is a cloudy area in the lens of your eye (the clear part of the eye that helps to focus light). Cataracts are very common as you get older. In Fact over 60 years of age, 80% were found to have some kind of cataract in Sri Lanka
At first, you may not notice that you have a cataract. But over time, cataracts can make your vision blurry, hazy, or less colorful. You may have trouble reading or doing other everyday activities. Over time, cataracts can lead to vision loss.
Symptoms of cataracts
When to see a doctor
Make an appointment for an eye exam if you notice any changes in your vision. If you develop sudden vision changes, such as double vision or flashes of light, sudden eye pain, or a sudden headache, see a member of your eye care specialist right away.
Types of cataracts
Around age 40, the proteins in the lens of your eye start to break down and clump together. This clump makes a cloudy area on your lens — known as a cataract. Over time, the cataract gets worse and makes more of your lens cloudy.
Pediatric cataracts affect babies and children. Babies may be born with cataracts (congenital), or the cataracts may form sometime after birth. Pediatric cataracts typically run in families, but they can also happen due to eye injuries or other eye conditions. Babies and children with pediatric cataracts need prompt treatment to prevent problems like amblyopia (lazy eye).
These cataracts form when something injures your eye. Treatment for this type is more complicated because structures around the lens may also need repair.
These are cloudy patches that form on your lens capsule, or the membrane that covers your lens. Another term for this condition is posterior capsular opacification. It’s a common but easily treatable complication of cataract surgery.
If you have cataract symptoms, it’s important to visit a doctor for a diagnosis so you can be treated. You may also be diagnosed by an optometrist/ ophthalmic technologist during a routine eye test, which should take place every two years.
During your eye exam, an eye specialist may test your vision by asking you to read letters or symbols from a chart and by performing a close check of your eyes to see if the lens has become cloudy.
Prescription glasses can help improve a person’s eyesight during the early stages of cataracts. However, it’s still important to seek further treatment, such as surgery, to prevent permanent sight loss.
Cataract surgery is the only way to restore vision. The operation is straightforward and effective. It involves removing the clouded lens from the lens capsule and replacing it with an artificial lens. A patient’s vision starts to return within a few hours of surgery.
In most cases, patients are given local anesthesia, which means that they are awake during the procedure and fully conscious of what is happening. Local anesthesia helps render the operation virtually painless, so patients don’t feel anything during surgery.
Cataract surgery can be done in around 15 minutes. It is considered a routine form of surgery, and it is performed on thousands of patients in Sri Lanka every year. In most cases, patients are given local anesthesia, which means that they are awake during the procedure and fully conscious of what is happening. Local anesthesia helps render the operation virtually painless, so patients don’t feel anything during surgery.
Diabetic retinopathy is a diabetes complication that affects eyes. It's caused by damage to the blood vessels of the light-sensitive tissue at the back of the eye (retina).
At first, diabetic retinopathy might cause no symptoms or only mild vision problems. But it can lead to blindness.
The overall prevalence of DM in Sri Lanka has been estimated to be 10.3% among those aged more than 20 years and it has been projected that the prevalence for 2030 will be 13.9%. One systematic review showed a “high epidemicity index“of DM (52.8%) in Sri Lanka compared to other countries in the region. The western province of Sri Lanka has the highest reported prevalence of DM in Sri Lanka, which is 18.6%
The condition can develop in anyone who has type 1 or type 2 diabetes. The longer you have diabetes and the less controlled your blood sugar is, the more likely you are to develop this eye complication.
Symptems of diabetic retinopathy
You can have diabetic retinopathy and not know it. This is because it often has no symptoms in its early stages. Diabetic retinopathy symptoms usually affect both eyes. As diabetic retinopathy gets worse, you will notice symptoms such as:
Seeing an increasing number of floaters,
Having blurry vision,
Having vision that changes sometimes from blurry to clear,
Seeing blank or dark areas in your field of vision,
Having poor night vision, and
Noticing colors appear faded or washed out
Losing vision.
Laser treatment usually works very well to prevent vision loss if it's done before the retina has been severely damaged. It may also help with macular edema.
Severe proliferative retinopathy may be treated with a more aggressive laser therapy called scatter (pan-retinal) photocoagulation. It allows your doctor to limit the growth of new blood vessels across the back of your retina. Laser treatments may not always work in treating proliferative retinopathy.
This surgery may help improve vision if the retina hasn't been severely damaged. It's done when there is bleeding (vitreous hemorrhage) or retinal detachment. These two problems are rare in people with early-stage retinopathy.
This surgery is also done when severe scar tissue has formed. It can be used to treat macular edema.
Anti-VEGF medicines slow the growth of abnormal blood vessels in the retina. This growth is triggered by a protein called vascular endothelial growth factor (VEGF). Anti-VEGF medicines block the effects of VEGF.
Sometimes injections of these types of medicine help to shrink new blood vessels in proliferative diabetic retinopathy.
Sometimes an implant, such as Iluvien, may be placed in the eye. The implant releases a small amount of corticosteroid over time.
Many people with diabetic retinopathy need to be treated more than once as the condition gets worse.
Glaucoma is a condition that damages your eye's optic nerve, and it gets worse over time. It's often linked to a buildup of pressure inside your eye. Glaucoma tends to run in families. You usually don’t get it until later in life.
The increased pressure in your eye, called intraocular pressure, can damage your optic nerve that sends images to your brain. If the damage worsens, glaucoma can cause permanent vision loss or even total blindness within a few years.
Most people with glaucoma have no early symptoms or pain. Visit your eye doctor regularly so they can diagnose and treat glaucoma before you have long-term vision loss.
If you lose vision, it can’t be brought back, but lowering eye pressure can help you keep the sight you have. Most people with glaucoma who follow their treatment plan and have regular eye exams are able to keep their vision.
Age-related macular degeneration (AMD) is the most common cause of severe loss of central vision among people 50 and older. AMD doesn’t cause complete blindness, but losing your central vision can make it harder to see faces, read, drive, or do close-up work like cooking or fixing things around the house. AMD is a problem with your retina. It happens when a part of the retina called the macula is damaged.
Who eat a diet high in saturated fat (found in foods like meat, butter, and cheese?)
Are overweight
Smoke cigarettes
Are over 50 years old
Have hypertension (high blood pressure)
Have a family history of AMD
There are two different types of AMD:
dry AMD and
wet AMD.
The good news is that there are effective treatments available for wet AMD.
Dry AMD (also called atrophic AMD) happens when the light-sensitive cells that make up the macula start to break down and die. This makes your macula break down and get thinner over time (usually over several years), causing mild-to-severe central vision loss.
Your ophthalmologist will put dilating eye drops in your eye to widen your pupil. This allows him or her to look through a special lens at the inside of your eye.
Your doctor may do fluorescein angiography to see what is happening with your retina. Yellow dye (called fluorescein) is injected into a vein, usually in your arm. The dye travels through your blood vessels. A special camera takes photos of the retina as the dye travels throughout its blood vessels. This shows if abnormal new blood vessels are growing under the retina.
Drusen is the earliest AMD sign that is detected clinically in fundus examinations. On Optical Coherence Tomography (OCT), drusen appear as retinal pigment epithelium (RPE) deformation or thickening that may form irregularities and undulations
If you’re diagnosed with wet AMD, there are two effective treatment options currently available:
Your doctor can give you shots of these medicines in your eye every one to three months. Researchers are working on ways to space out the time between doses, so that you don’t need to get the shots as often.
Your doctor can shine light at the back of your eyes to destroy the abnormal blood vessels that cause wet AMD.
Amblyopia is when vision in one or both eyes does not develop properly during childhood. It is sometimes called lazy eye. Amblyopia is a common problem in babies and young children.
A child’s vision develops in the first few years of life. It is important to diagnose and treat amblyopia as early as possible. Otherwise, a child with amblyopia will not develop normal, healthy vision.
How to detect amblyopia………..?
Symptoms of amblyopia can be hard to notice. Kids with amblyopia may have poor depth perception. They have trouble telling how near or far something is. Parents may also notice signs that their child is struggling to see clearly, like:
Squinting
Shutting 1 eye
Tilting their head
In many cases, parents don’t know their child has amblyopia until a doctor diagnoses it during an eye exam. That’s why it’s important for all kids to get a vision screening at least once between ages 3 and 5.
Amblyopia is thought to develop during a critical time in infancy and early childhood when visual development depends on the eyes and the brain's visual cortex working together. Inadequate stimulation of the visual pathways leads to disuse of the visual cortex and resultant amblyopia.
The major types of amblyopia are listed below…..
Strabismic amblyopia occurs when the eyes are misaligned. The visual cortex suppresses visual input from the deviating eye because the brain cannot fuse the different images from each eye. This type of amblyopia results in loss of binocular vision and thus, depth perception (stereopsis)
Anisometropic amblyopia (also called refractive amblyopia) occurs when there is a difference in visual acuity between the eyes, leading to the blurring of vision in one eye. The eye with the higher refractive error (more blur) requires greater effort to focus and form a clear image; therefore, it tends to remain unfocused. Chronic blur leads to amblyopia as the visual cortex ignores the chronically blurred visual input. Amblyopia is more commonly associated with anisometropia due to farsightedness or astigmatism rather than nearsightedness.
Ametropic amblyopia occurs in children with bilateral, symmetric high refractive error; the eyes cannot accommodate, and the blurred vision results in inadequate development of the visual cortex. Deprivation amblyopia results from obstruction of the visual axis by unusual conditions such as congenital ptosis or cataracts.
Refractive errors are a type of vision problem that makes it hard to see clearly. They happen when the shape of your eye keeps light from focusing correctly on your retina.
The parts of your eyes work together like a relay team to pass light that enters your eye along a pathway to your brain. Light passes through your cornea which the clear part at the front of your eye. Your cornea focuses that light through your lens into a signal that hits your retina which the layer at the very back of your eyeball. Your retina converts that light into electrical signals that your optic nerve sends to your brain. Your brain then uses those signals to create the images you see. Technically it means that the eye is not focus the light properly on retina. This eye disorder is not a preventable condition but is treatable.
What are the types of refractive errors?
There are 4 common types of refractive errors:
Nearsightedness (myopia) makes far-away objects look blurry
Farsightedness (hyperopia) makes nearby objects look blurry
Astigmatism can make far-away and nearby objects look blurry or distorted
Presbyopia makes it hard for middle-aged and older adults to see things up close
If you have a refractive error, your eye doctor can prescribe eyeglasses or contact lenses to help you see clearly.
Myopia is the medical name for nearsightedness. Myopia is a common vision condition in which near objects appear clear, but objects farther away look blurry. It occurs when the shape of the eye causes light rays to bend inaccurately. Light rays that should be focused on nerve tissues (retina) at the back of the eye are focused in front of the retina.
It affects a significant percentage of people. It’s an eye focus disorder that’s normally corrected with eyeglasses, contact lenses or surgery. Myopia cannot be cured once the patient is afflicted- though its further progress could be withheld when detected early.
One of the real causes, is the growing dependence on technology- with the younger generations especially spending too much time in front of screens- TVs, computers or hand held devices.
But the causa prima is that we are no longer exposed enough to natural light. Study, work and pleasure all tend to unravel indoors- mostly screened away from sunlight.
Among the best precautions is to limit screen time- and to play outside in natural light. Studies done in many countries indicate that exercising and outdoor activities have prevented children from being myopic.
If you have myopia, more than likely, at least one or both of your biological parents do, too. Eye experts are still unsure of the exact cause of myopia, but believe it to be a mix of hereditary and environmental factors.
It’s possible that you can inherit the ability to be myopic. If your lifestyle produces just the right conditions, you’ll develop it. For example, if you use your eyes for a lot of close-up work, like reading or working on a computer, you may develop myopia.
A healthy eye has a spherical cornea or lens, meaning the curves are the same. However, an eye with astigmatism has a steep curve and a flat curve, also known as the two principal meridians. To visualize this, imagine the eye is a clock with a line running vertically from 12 o’clock to six o’clock (the 90-degree axis) and another line running horizontally from three o’clock to nine o’clock (the 180-degree axis).
Regular astigmatism is when the two principal meridians are 90 degrees apart, with one meridian being steeper than the other. This type of astigmatism is most common and can be corrected by glasses, contact lenses, or laser surgery.
There are two main types of astigmatism:
Corneal astigmatism is when the cornea - the clear front part of the eye - is misshapen and not perfectly round.
Lenticular astigmatism is when the lens of the eye is misshapen.
Astigmatism is usually present at birth. However, it can result from:
An eye injury.
A scar.
An operation to the eye, particularly if the corneal surface is damaged.
Anything pressing persistently on the surface of the cornea (such as a large lump on the eyelid) which pushes it out of shape.
Your eyes play a crucial role in almost everything you do. To understand how you are able to see the world around you, it is helpful to understand the anatomy and physiology of the human eye.
The eye is the organ of vision and one of the most complex organs of the human body. Our eyes are
responsible for four-fifths of all the information our brain receives. The proper function of the eye depends on its ability to receive and process energy from light in the environment,
The eye is a slightly asymmetrical globe, about 24 mm in diameter. The two eye balls lie in quadrilateral pyramid shaped bony cavity called orbit. It situated on either side of the root of the nose.
The eye ball is composed of three concentric layers.
The outer layer consists of the transparent cornea, the opaque sclera and lamina cribrosa. Cornea cover anteriorly one sixth of the eye ball. The cornea refracts and transmits the light in to the eye. Posterior part is sclera. It forms a connective tissue coat that protects the eye from internal and external forces and maintains its shape. The nerve fibers forming the optic nerve exit the eye posteriorly through a hole in the sclera that is occupied by a mesh-like structure called the lamina cribrosa.
Midle layer of the eye is uveal tract. The uveal tract consists of a pigmented, highly vascular loose fibrous tissue that can be divided into three anatomical regions: anterior iris, central ciliary body, and the posterior choroid.
The iris colored part of your eye that controls the amount of light passing through the pupil.
The ciliary body is a ring-shaped thickening of tissue. It secrete aqueous humor into the posterior chamber. The aqueous humor then flows through the pupil into the anterior chamber.
The ciliary body is attached to the lens by connective tissue called the zonular fibers. Relaxation of the ciliary muscle puts tension on these fibers and changes the shape of the lens in order to focus light on the retina.
Choroid
Three components of inner nervous layer: retina
Pigment epithelium of the retina
Retinal photoreceptors
Retinal neurons.
The innermost light sensitive layer is the retina. It is composed of light sensitive cells known as rods and cones. The human eye contains about 125 million rods, which are necessary for seeing in dim light. Cones, on the other hand, function best in bright light. There are between 6 and 7 million cones in the eye and they are essential for receiving a sharp accurate image and for distinguishing colours.
(a) Anterior chamber – the space between the cornea and the iris diaphragm.
(b) Posterior chamber – the triangular space between the iris anteriorly, the lens and zonule posteriorly, and the ciliary body.
(c) Vitreous chamber – the space behind the lens and zonule.
(a) Aqueous humour – a watery, optically clear solution of water and electrolytes similar to tissue fluids except that aqueous humour has a low protein content normally.
(b) Vitreous humour – a transparent gel consisting of a three-dimensional 2 Basic Anatomy and Physiology of the Eye 7 network of collagen fibres with the interspaces filled with polymerised hyaluronic acid molecules and water. It fills the space between the posterior surface of the lens, ciliary body and retina.
(c) Blood – in addition to its usual functions, blood contributes to the maintenance of intraocular pressure. Most of the blood within the eye is in the choroid. The choroidal blood flow represents the largest blood flow per unit tissue in the body. The degree of desaturation of efferent choroidal blood is relatively small and indicates that the choroidal vasculature has functions beyond retinal nutrition. It might be that the choroid serves as a heat exchanger for the retina, which absorbs energy as light strikes the retinal pigment epithelium.
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