The normal crystalline lens of the eye is clear and transparent. Whenever the lens develops cloudiness or opacity, it is called a 'cataract'. This opacification obstructs light from being transmitted to the retina causing blurring of vision. This may be compared to a window that is frosted or fogged with steam.
CausesMost cataracts occur as a result of:
The normal process of aging may cause the lens to harden and turn cloudy.Other less common causes of development of cataract are:
- Injuries to the eye
- Infections or inflammations within the eye
- Certain medications
- Diabetes - can accelerate the process of cataract formation
- Rarely some children are born with cataracts - as a congenital abnormality
- Family history - cataract can occur at a much earlier age than otherwise expected, even as early as 20 years.
As the cataract develops:
- There may be hazy and blurred vision
- Double vision and distortion of images may occur
- The eye may be more sensitive to light glare therefore making night driving difficult
- Things may seem brighter with one eye than the other
- There may be a need to change glasses frequently
Glaucoma is a chronic, irreversible progressive disease of the optic nerve that affects approximately 70 million people around the world. It is the second most common cause of blindness and there are an estimated 7.5 million blind from the glaucoma, worldwide. It is most common cause for irreversible (permanent) blindness in the world including our India. In India, there are at least 12 million people affected with the glaucoma, 1.5 million are blind from the disease. The disease is more common in old age. The occurrence of glaucoma increases as age increases, approximately 2-3 persons per hundred persons are affected above the age 40 years. It is surprising to see that more than 90% of people are unaware of the glaucoma when first diagnosed even in urban area of metro cities.Diagnosis of Glaucoma
The diagnosis (or exclusion) of glaucoma requires a detailed, comprehensive examination of the eye. Your doctor will do the following examinations:
- A routine vision test that requires reading letters from a chart
- Slit lamp (microscope) examination
- Measurement of the pressure in the eye usually using the applanation tonometer attached to the slit-lamp microscope. A hand held version of same instrument is acceptable. It may be necessary to obtain multiple reading of the pressure during the course of the day and night.
- Examination of the angle of the eye using a gonioscope. Steps 3 and 4 require the use of a drop to eliminate the sensation in the eye.
Age Related Macular Degeneration
Age related macular degeneration (ARMD) is the leading cause of registered blindness in people over 50 years of age. Approximately 25-30 million people are affected by some form of ARMD. This number is expected to triple over the next 25 years.
Types of ARMDDry 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.Wet ARMD
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.Diabetic Retinopathy
Insulin is hormone that regulates the level of sugar (glucose) in the blood. Diabetes is a disease that occurs when the body does not secrete enough insulin or is unable to utilize it property causing sugar levels to increase. Diabetes can affect children and adults.
Causes of Vision LossDiabetic Maculopathy
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.Vitreous hemorrhage (bleeding)
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.Retinal detachment
Macular wrinkling can cause visual distortion. More severe vision loss can occur if the macula or large areas of the retina are detached.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.
Congenital or developmental cataract is an important cause of childhood blindness. Not everybody is aware that cataracts can occur even in small children or it may even be present since birth. In nearly half of all paediatric cataracts the cause cannot be found out. Paediatric cataracts are responsible not only for blocking the light rays from reaching the retina but also can cause lazy eyes if not treated at the right time.
It is usually present at birth or soon after birth and is diagnosed by the appearance of white dots in the center of the eyes without the use of any special instrument. Some children may fail to show visual awareness of the world around him or her (if cataracts present in both eyes). Some others may develop 'cross eyes'(squint) or 'dancing eyes' (nystagmus).
Vernal keratoconjunctivitis is a type of allergic disorder of the eye that usually affects children in the age group 3 to 15 years. It is a recurrent eye inflammatory disorder that has a seasonal incidence. Some people experience symptoms year round, however the peak season for vernal conjunctivitis is between March and August. It tends to occur more in dry, warm climates. Exposure to dust and other allergens like pollen can exacerbate the condition.
Patients usually complain of redness, itching and mucoid discharge of eyes. Some children have severe itching and keep rubbing their eyes vigourously throughout the day. The rubbing of eyes increases the redness in the eyes. Children with severe form of the disease also develop intolerance to bright light and avoid going outdoors. The disease usually does not threaten the vision unless in very advanced conditions. The symptoms described above may not necessarily mean that you have vernal keratoconjunctivitis. However, if you experience one or more of these symptoms, contact your eye doctor for a complete exam.
A "squint" is the common name for 'strabismus' or 'heterotropia', which is the medical term used to describe eyes that are not pointing in the same direction, or which are misaligned. Squint occurs due to a lack of coordination between the eyes resulting in a crossed eyed appearance when looking at an object the eyes will turn without unison.
Squints are best managed by specialists in paediatric ophthalmology & strabismus. They have undergone special training in diagnosis and treatment of squints and other eye disorders in children. Squints cannot be outgrown, nor will it improve by itself. Treatment to straighten the eyes is required.
Blepharoptosis, also referred to as ptosis, is defined as an abnormal low-lying upper eyelid margin with the eye in primary gaze.
- Weakness of the muscle that raises the eyelid.
- Damage to the nerves that control that muscle.
- Looseness of the skin of the upper eyelids.
- The primary symptom of ptosis is a visible drooping of the upper eyelid (eye appearing smaller).
- Frequent eyebrow raising and head tilting can indicate that ptosis is interfering with normal sight.
- Amblyopia (Lazy eyes) in delayed cases.
The eye surgery is usually very successful in restoring appearance and function. Surgery is done as a day care procedure by an Oculoplasty surgeon. The surgery does not involve any manipulation of the eyeball; hence the vision is not affected by this surgery. However in children if the surgery is delayed it may lead to subnormal vision (Amblyopia).
The cornea is the front, outermost layer of the eye. Just as a window lets light into a room, the cornea lets light into the eye. It also focuses the light passing through it to make images clear and sharp.
Corneal problems can occur in anyone regardless of age. Sometimes due to disease, injury or infection the cornea becomes cloudy or warped. A damaged cornea, like a frosted or misshapen windowpane, distorts light as it enters the eye. This not only causes distortion in vision, it may also cause pain.
When there is no other remedy, doctors advise a corneal transplant. In this procedure an ophthalmologist surgically replaces the diseased cornea with a healthy one to restore clear vision.
Types of Corneal SurgeriesLamellar corneal surgeries
Including Deep Anterior Lamellar Keratoplasty (DALK), Deep Lamellar Endothelial Keratoplasty (DLEK) and Descemet's Stripping EndoKeratoplasty (DSEK), Automated Lamellar Therapeutic Keratoplasty (ALTK)Refractive corneal surgery
Refractive surgery offers the state of art facility for various laser refractive procedures like LASIK, Epi-LASIK, PRK and Wavefront guided customized ablation