What is the retina?
The retina is the back surface inside the eyeball, opposite the lens. It contains millions of light sensitive photoreceptor cells, called rods and cones. An image projected by the lens onto the retina is sensed by the rods and cones as different intensities of light and different colors. When light hits rods or cones, a biochemical reaction occurs, which initiates the transmission of signals along nerve cells to the brain, with information about light, color and position in the retina. In the brain, the signals from throughout the retina are assembled into the experience of seeing what is before us.
What is the macula?
The central portion of the retina directly opposite the lens, is called the macula. It is rich in cones, the cells which enable us to see fine detail and color. There are three classes of cones, each most sensitive to a different color: red, green or blue.
What is the fovea?
At the center of the macula is very small area called the fovea. Cones are most concentrated in the fovea. Despite its small size, relative to the rest of the retina, the fovea is very important for our ability to see fine detail and color.
What is Macular Degeneration?
Macular Degeneration is a blinding disease which causes the death of cells in the light-sensitive portion of the eye called the retina. These cells, called photoreceptor cells, are most severely affected in a specialized region of the retina called the macula, thus the name Macular Degeneration. The macula is responsible for what is called "fine acuity vision"; this is the vision that you use when driving, reading, sewing, watching television or any activity that requires one to focus on very small objects. Loss of the light-sensitive cells in the macula has devastating effects on vision and can lead to total blindness.
If I develop "wet" or "dry" ARMD in one eye, will it eventually affect the opposite eye?
Probably. The fellow eye is at high risk of following SUIT, but the timing can vary significantly from person to person.
How does normal vision develop?
Newborn infants are able to see, but as they use their eyes during the first few months of life, vision improves. During the early childhood years, the visual system changes quickly and vision continues to develop. If a child cannot use his or her eyes normally, vision does not develop properly and may even decrease. After the first nine years of life, the visual system is usually fully developed and usually cannot be changed.
The development of equal vision in both eyes is necessary for normal vision. Many occupations are not open to people who have good vision in only one eye. If the vision in one eye should be lost later in life from an accident or illness, it is essential that the other eye have normal vision. Without normal vision in at least one eye, a person is visually impaired.
Why did my eyelid start to twitch?
Mild twitching of the eyelid is a common phenomenon. Although these involuntary contractions of muscles are annoying, they are almost always temporary and completely harmless. The medical name for this kind of twitching is ocular myokymia. It is quite common and most often associated with fatigue. When your eye is twitching, it is not visible to anyone else.
How can I make it stop?
Ophthalmologists often are asked what causes the twitching and what can be done to stop it. Lack of sleep, too much caffeine or increased stress seem to be root causes. Often, gently massaging your eye will relieve the symptoms. Usually, the twitch will disappear after catching up on your sleep.
What is Dry Eye Syndrome?
Dry eye syndrome is a leading cause of ocular discomfort affecting millions of people. Dry eye conditions are a spectrum of disorders with varied etiology ranging from mild eyestrain to very severe dry eyes with sight threatening complications.
Although the typical patient of dry eyes is elderly, or suffers from autoimmune disease, increasing numbers of patients do not fit this profile. Younger patients who work with computers can suffer from dry eyes more often than elderly patients. Dry eye condition is also aggravated in polluted conditions, dry weather, decreased ambient humidity as seen with air conditioning and indoor heaters. It may also result from the abnormalities in one or more of the tear film components, ocular or systemic diseases, and various drugs. Dry eye syndrome is usually treated with tear supplements and lubricants. However, if these do not help, microscopic plugs (temporary or permanent) can be inserted to help conserve tears and prevent them from draining away. In severe cases, surgical intervention may be essential.
What is Cataract?
It is a cloudiness of the normally clear lens in the eye. It prevents the lens from focusing light onto the retina and hence causes unclear vision. As the cataract advances, this cloudiness of vision increases over a period of time until the vision is completely impaired.
Symptoms of developing cataract?
Because cataracts form in different ways, the symptoms of cataracts are variable. Most people notice that their vision gradually deteriorates – objects may begin to look yellow, hazy, blurred or distorted. Some people report double vision, or polyopia (objects appearing multiple). Many people also find that they need more light to see clearly, or that they experience glare or haloes from lights at night. A common problem encountered is increasing nearsightedness. In advanced cases, the cataract may be visible as a whitish-looking pupil.
When to consider surgery?
The eye doctor will discuss and guide about whether surgery is right for you. Most eye doctors suggest considering cataract surgery when your cataracts begin to affect your quality of life or interfere with your ability to perform normal daily activities, such as reading or driving at night.
Cataract surgery is a procedure to remove the lens of your eye and, in most cases, replace it with an artificial lens. Cataract surgery is used to treat the clouding of the normally clear lens of your eye (cataract). The surgery is done through using Phacoemulsification. Most recently Laser treatment is used for Cataract surgery.
Intra Ocular Lens:
The decision of Intra Ocular Lens (IOL) to be implanted in the eye is decided by the patient in consultation of the surgeon. There are options available which gives the best quality of surgical outcome for the patient. These are Monofocal IOL, Toric IOL, Trifocal IOL and Multifocal IOL.
Monofocal IOL treats a patient with distance vision.
Toric IOL is suggested for the patient who has high astigmatism.
Trifocal & Multifocal IOL are suggested for the patients who wants least dependency on glass for both distance and near. It gives a superior quality of surgical outcome for distance, intermediate and near vision.
What is Keratoconus?
Normally the cornea is nearly spherically shaped thus allowing light to be focused clearly on the back of the eye (retina). However in a condition called Keratoconus, the cornea begins to thin, and this makes the cornea bulge forward taking on a cone-shape. As the cornea gradually becomes more cone-shaped, the vision blurs and becomes distorted due to a high degree of astigmatism. Initially vision may be correctable with spectacles, but as the condition progresses, and the cornea becomes more irregular causing distorted vision, spectacles become less effective. In such a situation, contact lenses not only provide better vision, but also help to retard the progress of the disorder. A rigid contact lens (RGP / “semi-soft” contact lenses) must be used, so that it can hold its shape, as a soft lens would simply mould to the existing shape and thus not allow complete correction of the problem. Sometimes the patient is fitted with soft lenses (for comfort), over which semi-soft lenses are fitted (“piggy-back” lenses). Currently, Rose K contact lenses are prescribed for patients of keratoconus. These provide superior vision, better fit and comfort to the patients.
Fitting contact lenses for keratoconus requires expertise. Well-fitting contact lenses dramatically improves such a patient’s vision to nearly that of a normal person’s, and significantly improves his or her quality of life. Any excessive pressure of a poorly fitting lens on the cone apex can cause permanent scarring within months or years (This scarring can also occur naturally). For this reason it is important for regular follow-up visits to be made so that any corneal changes that have occurred can be compensated for in the design of a new lens. It is quite common for patients to be refitted at irregular intervals as the condition progresses. Rarely, scarring is so severe that a corneal graft (transplant) is necessary.
A recent promising treatment modality for keratoconus is C3R (Corneal Collagen Cross-linking with Riboflavin). MM Eyetech Institute now offers you Cross Linking of the Cornea with Riboflavin (C3R), which is a new approach to increase the mechanical stability of corneal tissue. The aim of this treatment is to create additional chemical bonds inside the corneal stroma by means of a highly localized photo polymerization.
The indications for cross linking today are corneal ectasia. Disorders such as keratoconus, pellucid marginal degeneration, iatrogenic keratectasia after refractive lamellar surgery and corneal melting that is not responding to conventional therapy are some of the common indications for C3R procedure.
What is Cornea Transplant?
Corneal transplantation, or keratoplasty is also known as corneal grafting. It is an operation designed to correct blindness resulting from corneal disease. It involves removal of damaged or diseased cornea (the recipient) which is replaced by donated healthy corneal tissue (the graft) either in its entirety (penetrating keratoplasty) or in part (lamellar keratoplasty). The graft is taken from a recently deceased individual with no known diseases or other factors that may affect the viability of the donated corneal tissue or the general health of the recipient.
Only the corneal tissue (and not the whole eye) donated by one person is transplanted into the diseased eye of another person who has been blinded by a corneal scar or disease.
What is Glaucoma?
Glaucoma, otherwise known as “Kala Motia” is an eye disease in which there is an increase in pressure inside the eye. Just as some people have high blood pressure, in the same way a glaucoma patient has high eye pressure.
If the eye pressure remains high for a long time it damages the optic nerve which carries the light sense from the eye to the brain. This damage to the nerve is irreversible and leads to permanent and incurable blindness. That is why glaucoma is a dangerous disease of the eye and has been labeled as “lurking thief of vision”. Glaucoma is the second leading cause of blindness in the world with 70 to 105 million people affected worldwide (WHO).
Glaucoma is usually asymptomatic or is associated with very mild symptoms which the patient often tends to ignore. Some of the early symptoms include:
- Frequent change of reading glasses.
- Mild eye ache or headache towards the evening after a day’s work.
- Seeing rainbow colored haloes of light around a bulb associated with slight decrease in vision.
- Inability to adjust one’s vision on entering a dark room. ” Difficulty in focusing on close work.
- In advanced cases, there is a loss of side vision, while the central vision remains good. The patient becomes more prone to accidents as he/she is unable to perceive vehicles or objects coming from the sides.
- It is to be remembered, that cataract (“Safed Motia”) also starts developing at the same age as glaucoma. Many people may think that they are losing vision due to cataract whereas it may actually be due to glaucoma, which is a much more dangerous disease.
- It is therefore advisable to undergo a routine examination around the age of 40 years, and every 5 years thereafter to screen for glaucoma.
Detection of Glaucoma:
- Vision Testing
- Measurement of Eye Pressure
- Evaluation of Optic Nerve Damage
- Evaluation of Drainage Channel
- Evaluation of Visual Field
- Retinal Nerve Fibre Analyzer (OCT)
Treatment of Glaucoma:
- Medical Treatment
- Yag Laser Peripheral Iridotomy
- Glaucoma Surgery
What is Refractive Error?
In the human eye, the front surface (cornea) and lens inside the eye form the eye’s “focusing system” and are primarily responsible for focusing incoming light rays onto the surface of the retina, much like the lenses of a camera focus light onto the film. In a perfect optical system, the power of the cornea and lens are perfectly matched with the length of the eye and images are in focus; any mismatch in this system is called a refractive error, and the result is a blurred image at some location.
What are the primary types of refractive error?
Myopia (nearsightedness): In people with myopia, the mismatch in focusing power and eye length causes distant objects to be blurry and near objects to be clearer. Hyperopia (farsightedness): In people with hyperopia, the mismatch in focusing power and eye length causes near objects to be blurry and distant objects to be relatively clearer. Astigmatism: In people with astigmatism, either the corneal or lens shape is distorted, causing multiple images on the retina. This causes objects at all distances to appear blurry. Many people have a combination of either myopia or hyperopia with astigmatism.
How do glasses or contacts improve vision in people with refractive errors?
Glasses or contact lenses are used to compensate for the eye’s refractive error by bending light rays in a way that complements the eye’s specific refractive error. In contrast, LASIK Eye surgery and other forms of refractive surgery are intended to correct the eye’s refractive error to reduce the need for other visual aids.
What is LASIK?
LASIK stands for laser in situ keratomileusis, which means using a laser underneath a corneal flap (in situ) to reshape the cornea (keratomileusis). This procedure utilizes a highly specialized laser (excimer laser) designed to treat refractive errors, improve vision, and reduce or eliminate the need for glasses or contact lenses. This laser procedure alters the shape of the cornea, which is the transparent front covering of the eye. Though the excimer laser had been used for many years before, the development of LASIK is generally credited to Ioannis Pallikaris from Greece around 1991.
How does LASIK Eye Surgery work?
During the LASIK Eye Surgery procedure, a specially trained eye surgeon first creates a precise, thin hinged corneal flap using a microkeratome. The surgeon then pulls back the flap to expose the underlying corneal tissue, and then the excimer laser reshapes the cornea in a unique pre-specified pattern for each patient. The flap is then gently repositioned onto the underlying cornea without sutures.
What are the different types of LASIK?
There are a variety of lasers used in ophthalmology. All LASIK procedures are performed with a specific type of laser (excimer laser), so in one sense, all LASIK procedures are similar. However, there are a variety of different laser manufacturers, who have all designed specific excimer lasers. Further, there are different types of laser ablations that can be performed (see below), including conventional laser treatments, wavefront-optimized treatments, and wavefront-guided treatments. Finally, a completely different type of laser (femtosecond laser) can be used instead of a mechanical microkeratome to create the LASIK (corneal) flap.
What are the advantages of LASIK Eye surgery?
In summary, despite the risks outlined above, LASIK has been proven to be safe and effective for most people. With careful patient screening and selection, reasonable expectations, and in the care of an experienced surgeon, most patients will be very pleased with their results. These are some of the other advantages of LASIK:
LASIK is able to accurately correct most levels of myopia (nearsightedness), hyperopia (farsightedness), and astigmatism. The procedure is fast, usually lasting only 15 minutes, and is generally painless. Because the laser is guided by a computer, it is very precise and results are very accurate. In most cases, a single treatment will achieve the desired outcome; however, enhancements are possible if needed, even many years after the initial surgery.
What are the disadvantages of LASIK Eye surgery?
Because each patient will heal slightly differently, results may vary from patient to patient. LASIK could make some aspects of your vision worse, including night vision with glare and halos. LASIK may make dry-eye symptoms worse in certain individuals. In rare circumstances, LASIK can make your vision worse and not correctable with regular glasses or contact lenses.