Amblyopia or "lazy eye" is reduced vision in an eye due to a lack of normal visual development during childhood. An amblyopic eye that does not see well early in life does not develop normal vision even with glasses. Amblyopia affects 3-4% of children and usually involves one eye though rarely can involve both. It may be the result of needing a different spectacle prescription in each eye, an opacity such as a cataract, or misalignment of the eyes. After the first nine years of life, the visual system is usually fully developed and cannot be significantly changed. The best time to correct amblyopia is during infancy or early childhood.
The presence of amblyopia is not always easy to recognize. Children should have their vision tested by their eye doctor at the age of four or earlier if there is any "wandering" of the eyes. Children with a family history of amblyopia should be checked even earlier within the first two to three years of life. Failing a vision screening does not always mean there is amblyopia as vision is often improved back to normal by prescribing glasses.
Amblyopia is treated by patching the stronger eye to strengthen the weaker eye. Patching may vary from a few hours a day to almost the entire day depending upon the visual acuity. Sometimes drops are used instead of patching to blur the better eye if cooperation is a problem.
If amblyopia is not treated, the weaker eye may permanently have poor vision which is uncorrectable with glasses.
If the problem is detected early, patching can help to improve vision in most children..
Cataracts are cloudy areas in the lens of the eye -which is normally clear, letting light pass through.
When cataracts are present, vision becomes hazy because light no longer passes through easily. If cataracts progress and become large and dense, they can be surgically removed in what is usually a safe, outpatient procedure. Cataract surgery is a personal choice and should be considered when cataracts cause enough loss of vision to interfere with daily activities. A cataract can only be removed using surgical techniques, although cataract surgery by lasers is being done experimentally. Intraocular lens implants often replace the natural lens, and about one-fifth of people later develop a clouding in the lens area; in this situation, laser surgery is used to create a "window" to help restore clear vision.
Cataracts are most common in the aging eye, but also occur in younger people and people with diabetes.
Cataracts may develop slowly, or quickly, and at differing rates in each eye.
"Conjunctivitis" refers to inflammation or infection of the membrane lining the "white" of the eye and the inside of the eyelids. It is very common, and can vary from a mild redness to a severe condition causing damage to the eye. # The most common type of conjunctivitis is viral. This will disappear on its own but is very contagious and can spread rapidly, especially among children. It is important that hands be washed frequently and kept away from the face. Towels should not be shared.
Bacterial conjunctivitis is much less common and is treated with antibiotics. Bacterial conjunctivitis generally has a lot of purulent (pus-like) drainage from the eye.
The hallmark of allergic conjunctivitis is itch. When a material that a person is allergic to makes contact with the eye, a reaction is set up that leads to redness, itching and tearing of the eyes with puffy eyelids. Rubbing the eyes, which gives momentary relief from the itch, only makes the inflammation and itching worse. The best treatment is to avoid the cause of the itch, if possible. Often this is not possible since the inciting material may be present everywhere, such as grasses, dust and mould. Cool compresses may offer some relief. Also effective are lubricating eye drops and antihistamine eye drops, both of which are over-the-counter medicines.
For more severe conditions, examination and treatment by an eye doctor may be necessary. There are many prescription medications now available that give substantial relief to most people.
Not all red eyes have conjunctivitis. The conjunctiva can also be red due to dry eye, foreign body and inflammations inside the eye.
The commonest complication of diabetes is diabetic retinopathy, which is a deterioration of the blood vessels that nourish the retina. If these weakened vessels leak fluid or blood, they can damage or scar the retina and ultimately blur vision. About 60 percent of people with diabetes more than 15 years have some blood vessel damage in their eyes. However, only a small percentage of those people have serious vision problems. Diabetic retinopathy is a leading cause of new blindness among adults in Ireland. Pregnancy and high blood pressure may worsen this condition in diabetic patients. The best protection against the progression of diabetic retinopathy is awareness of the risks of developing sight disturbances and having regular examinations by an eye doctor. When treatment is necessary, the most common method is laser surgery to seal the leaking blood vessels.
Although approximately 80% of Type 1 diabetics (i.e., insulin-dependent) have retinopathy after 15 years of disease, only about 25% have any retinopathy after 5 years. The prevalence of proliferative diabetic retinopathy (PDR) is less than 2% at five years and 25% by 15 years. For Type 2 diabetes (non-insulin-dependent), however, the onset date of diabetes is frequently not precisely known and thus more severe disease can be observed soon after diagnosis. Up to 3% of patients first diagnosed after age 30 (Type 2) can have clinically significant macular edema or high-risk PDR at the time of initial diagnosis of diabetes.
Glaucoma is a leading cause of blindness in Ireland, loss of sight from glaucoma may be preventable, if detected early enough.
Glaucoma is a disease of the optic nerve (the part of the eye that carries the images we see to the brain), caused when pressure in the eye builds up because the eye's usual drainage capability becomes blocked. Consequently, if the pressure inside the eye becomes too high, the optic nerve may become damaged, causing blind spots. If the glaucoma either has gone undetected for a while or the pressure increases rapidly, the entire nerve can be destroyed, and blindness results. Glaucoma can strike at any age, but at greatest risk are people with a family history of glaucoma, those aged 40 or older, or anyone who suffered a serious eye injury.
Most forms of glaucoma are painless, so early detection and treatment by your eye > doctor are the keys to prevention. Treatment commonly consists of medicated eye drops, but surgery may be required
Macular degeneration affects the part of the eye called the macula. The macula is part of the retina, the inner lining of the back of the eye. Light focused on the retina is transformed to an electrical signal that is sent to the brain where 'seeing' takes place.
The macula is the tiny central part of the retina that is responsible for the sharp, straight-ahead vision that we use for seeing fine details, reading, driving, recognising people at a distance, or seeing street signs. Other parts of the retina are used for side (peripheral) vision.
The most common type of macular degeneration is called age related macular degeneration (AMD), because it usually occurs after age 60. AMD usually develops very slowly.
There are two main types of AMD. About 85-90% of patients have the 'dry type' in which the outer layers of the retina slowly break down. This leads to a gradual blurring of vision that people may find noticeable when they try to read. There is no known treatment to slow of cure this type of AMD. Vision loss tends to be more severe from the second type of AMD, the 'wet form'. Compared with the dry form, vision may change quickly in wet AMD. Patients say that straight lines appear crooked and distorted, an affect caused by abnormal blood vessels growing under the retina. The vessels can leak fluid and bleed, lifting up the retina. In some cases, the vessels can be closed off to stop the leakage with laser treatment but vision may or may not improve afterwards, since abnormal blood vessels can grow back after laser treatment.
Macular degeneration is one of the commonest causes of vision loss in older adults. It does not, by itself, result in total blindness. While AMD can take away much useful central vision, causing inability to read or to drive a car, peripheral (side) vision, is not usually, allowing the person to move about independently and to continue those activities that do not require detailed vision. Most people who have had severe vision loss from macular degeneration, can be assisted with low-vision aids for reading.
With 'wet' macular degeneration patients can notice a gradual or sudden deterioration in, especially reading vision, in the affected eye. Some patients observe distortion of vision which indicates accumulation of fluid under the retina.
Dr Mark Cahill, eye surgeon discusses AMD on Drivetime with Mary Wilson
RTÉ Radio 1, Tuesday 20th September 2011
Prevention of Eye Injuries
Prevention of eye injuries is essential. Modifying risk factors and implementigappropriate eyewear protection can reduce the rates of ocular injury while allowing patients to maintain a productive career and enjoy their leisure pursuits.
Violence is a significant cause of ocular trauma. Assault related injuries involve predominately young males together with alcohol or drugs unsettled social environment and unemployment. Where appropriate law enforcement and social services should be used to prevent violence.
Almost every type of sport has been associated with eye injury. Ideally any participant participating in an at risk support should weaar pritective devices.
Many injuies occur in the work placewhere safety eyewear is inadequate or not worn. Company management must be involved in preventative strategiesto improve safety in the workplace.
Eyewash stations should be available where there is a a risk of chemical injury.