Short descriptions of common eye conditions
- Blepharitis: A common inflammatory condition that affects the eyelids. It usually causes burning, itching and irritation of the lids. In severe cases, it may also cause styes, irritation and inflammation of the cornea (keratitis) and conjunctiva (conjunctivitis). Some patients have no symptoms at all. It is usually a chronic problem that if prone, can flare up on and off throughout life and can cause permanent loss of lashes if not kept under control. Rawlings stock the following specialist lid cleaning solutions: Blephasol, Lidcare and Supranettes. The Eyebag is a hot compress designed for lid problems and is simply heated in a microwave or warm oven and is held at all our branches. Sometimes artificial tears can also help alleviate discomfort.
- Branch Retinal Vein Occlusion: Branch and central retinal vein occlusion occurs when the circulation of a retinal vein becomes obstructed by an adjacent blood vessel, causing hemorrhages in the retina. Swelling and ischaemia (lack of oxygen) of the retina as well as glaucoma are fairly common complications. The visual symptoms can vary in severity from one person to the next, and are dependent on whether the central retinal vein or a branch retinal vein is involved. Patients who experience a branch vein occlusion often notice a gradual improvement in their vision as the haemorrhage resolves. Recovery from a central vein occlusion is much less likely since it affects the macula. This problem appears equally in males and females and is more common after the age of 60.
- Cataracts: A clouding of the natural lens, the part of the eye responsible for focusing light and producing clear, sharp images. The lens is contained in a sealed bag or capsule. As old cells die they become trapped within the capsule. Over time, the cells accumulate causing the lens to cloud, making images look blurred or fuzzy. For most people, cataracts are a natural result of ageing.
- Central Retinal Vein Occlusion: (See Branch Retinal Vein Occlusion)
- Conjunctivitis: commonly known as pink eye, is an infection of the conjunctiva (the outer-most layer of the eye that covers the sclera). The three most common types of conjunctivitis are: viral, allergic, and bacterial. Each requires different treatments. With the exception of the allergic type, conjunctivitis is typically contagious.
- Corneal Ulcer: May form when the surface of the cornea is damaged or compromised. Ulcers may be sterile (no infecting organisms) or infectious. The term infiltrate is also commonly used along with ulcer. Infiltrate refers to an immune response causing an accumulation of cells or fluid in an area of the body where they don't normally belong. Whether or not an ulcer is infectious is an important distinction for the doctor to make and determines the course of treatment. Bacterial ulcers tend to be extremely painful and are typically associated with a break in the epithelium, the superficial layer of the cornea. In some cases, the inflammatory response involves the anterior chamber along with the cornea. Certain types of bacteria, such as Pseudomonas, are extremely aggressive and can cause severe damage and even blindness within 24-48 hours if left untreated.
- Diabetic Retinopathy: People with diabetes are more likely to develop eye problems such as cataracts and glaucoma, but the disease's affect on the retina is the main threat to vision. Most patients develop diabetic changes in the retina after approximately 20 years. The effect of diabetes on the eye is called diabetic retinopathy. Over time, diabetes affects the circulatory system of the retina. The earliest phase of the disease is known as background diabetic retinopathy. In this phase, the arteries in the retina become weakened and leak, forming small, dot-like hemorrhages. These leaking vessels often lead to swelling or edema in the retina and decreased vision. The next stage is known as proliferative diabetic retinopathy. In this stage, circulation problems cause areas of the retina to become oxygen-deprived or ischemic. New, fragile, vessels develop as the circulatory system attempts to maintain adequate oxygen levels within the retina. This is called neovascularization. Unfortunately, these delicate vessels hemorrhage easily.
- Dry Eye Syndrome is very common. It is usually caused by a problem with the quality of the tear film that lubricates the eyes. One of the most common reasons for dryness is simply the normal aging process. As we grow older, our bodies produce less oil - 60% less at age 65 than at age 18. This is more pronounced in women, who tend to have drier skin than men. The oil deficiency also affects the tear film. Without as much oil to seal the watery layer, the tear film evaporates much faster, leaving dry areas on the cornea. Many other factors, such as hot, dry or windy climates, high altitudes, air-conditioning and cigarette smoke also cause dry eyes. Many people also find their eyes become irritated when reading or working on a computer. Stopping periodically to rest and blink keeps the eyes more comfortable. Contact lens wearers may also suffer from dryness because the contacts absorb the tear film, causing proteins to form on the surface of the lens. Certain medications, thyroid conditions, vitamin A deficiency, and diseases such as Parkinson's and Sjogren's can also cause dryness. Women frequently experience problems with dry eyes as they enter menopause because of hormonal changes.
- Ectropion is a sagging lower eyelid that leaves the eye exposed and dry. It is caused by a lack of tone of the delicate muscles that hold the lid taut against the eye. Excessive tearing is common with ectropion, but wiping the tears away only causes the lid to sag more. Ectropion is most common among people over the age of 60.
- Entropion: An eyelid that turns inward, is a problem that typically affects the lower lid. It usually stems from a muscle spasm; however, it can also be caused by scarring from trauma or inflammation from certain diseases that involve the eyelids. When the eyelid turns inward, the lashes rub against the eye, resulting in irritation, scratchiness, tearing and redness. Surgery is often required to correct the problem.
- Episcleritis: an inflammatory condition of the connective tissue between the conjunctiva and sclera known as the episclera. The eye's red appearance makes it look similar to conjunctivitis, or pink eye, but there is no discharge or tearing. It usually has no apparent cause; however, it is sometimes associated with systemic inflammatory conditions such as arthritis, lupus, and inflammatory bowel disease. Rosacea, herpes simplex, gout, tuberculosis, and other diseases are also occasionally underlying causes. Women are typically affected by episcleritis more frequently than men. It characteristically occurs in people who are in their 30's and 40's and is often a recurrent problem.
- Floaters and/or Flashes: If you suddenly notice floaters or flashes in your vision you should have your eyes checked the same day. Usually the advice would be to attend your local eye casualty or A&E for urgent attention. The space between the crystalline lens and the retina is filled with a clear, gel-like substance called vitreous. With age, the vitreous thins and may separate from the back of the eye. This is called posterior vitreous detachment, a very common, usually harmless condition. As the vitreous pulls free from the retina, it is often accompanied by light flashes or floaters. Floaters are caused by tiny bits of vitreous gel or cells that cast shadows on the retina. Flashes occur when the vitreous tugs on the sensitive retina tissue. There are other more serious causes of flashes and floaters, however. Retinal tears, retinal detachment, infection, inflammation, hemorrhage, or an injury such as a blow to the head may also cause floaters and flashes. (Have you ever seen stars after bumping your head?) Occasionally, flashes of light are caused by neurological problems such as a migraine headache. When related to a headache, the flashes of light are seen in both eyes and usually last 20-30 minutes before the headache starts.
- Glaucoma is a disease of the optic nerve and one risk factor is increased intraocular pressure (IOP) resulting either from a malformation or malfunction of the eye's drainage structures. Left untreated, an elevated IOP causes irreversible damage to the optic nerve and retinal fibers resulting in a progressive, permanent loss of vision. However, early detection and treatment can slow, or even halt the progression of the disease. The eye constantly produces aqueous, the clear fluid that fills the anterior chamber (the space between the cornea and iris). The aqueous filters out of the anterior chamber through a complex drainage system. The delicate balance between the production and drainage of aqueous determines the eye's intraocular pressure (IOP). Most people's IOPs fall between 8 and 21. However, some eyes can tolerate higher pressures than others. That's why it may be normal for one person to have a higher pressure than another.
- Keratitis is a term used to define a wide variety of corneal infections, irritations, and inflammations; since each type of condition is unique, medical diagnosis and treatment is essential. Corneal ulcers are commonly caused by bacterial or fungal invasions following superficial corneal abrasions; among the common infectious agents are: staphyloccus, streptococcus, herpes (both simplex and zoster), adenovirus, rubeola, rubella, mumps, trachoma, infectious mononucleosis, and pneumococcus; also at fault may be Vitamin A deficiency or broad spectrum antibiotic drug reactions. Corneal ulcers may also follow trauma, may be associated with other eye infections (e.g., conjunctivitis), may be related to other corneal disorders (e.g., degenerative conditions, or ptosis, which may cause a "dry eye"), or may arise from a variety of systemic disorders (especially those of autoimmune origin). Symptoms of corneal infection include extreme pain and photophobia.
- Keratoconus is a degenerative disease of the cornea that causes it to gradually thin and bulge into a cone-like shape. This shape prevents light from focusing precisely on the macula. As the disease progresses, the cone becomes more pronounced, causing vision to become blurred and distorted. Because of the cornea's irregular shape, patients with keratoconus are usually very short sighted and have a high degree of astigmatism that is not correctable with glasses.
- Macular Degeneration:Age-related Macular Degeneration (AMD) is a condition that can affect your eyes as you get older. In fact, in the over 50s, AMD is the leading cause of sight loss in the UK.
AMD affects the macula - the small part of the eye responsible for central vision which allows you to see detail. AMD usually starts in one eye and is highly likely to affect the other eye at a later stage.
Dry AMD is the most common form of the condition and develops slowly, eventually leading
to loss of central vision. Wet AMD is caused by leaky blood vessels inside the eye. It is less common that dry AMD but it can cause more rapid loss of vision.
Today in the UK, there are up to 500,000 people with AMD. However, less than 1 in 7 people with AMD will have the type of AMD that will cause rapid sight loss (wet AMD).
The chances of getting AMD do increase as you get older. However, most people get the dry form and this is currently untreatable. Wet AMD can in some cases be treated and sight loss reduced, if it is spotted in time. In both cases, help and support is available from low vision services. For more information click here.
The exact causes of AMD are still unknown. It appears that AMD runs in families, so if any of your close relatives have suffered with loss of eyesight then it may be worth getting your eyes checked more regularly. Studies have shown a definite link between smoking and AMD. Other factors such as high blood pressure and poor diet can also lead to a greater risk of getting AMD. Indeed, recent research (AREDS study) has shown that vitamins (C & E), beta-carotene, copper and zinc supplements in your diet, can help reduce the risk of developing AMD. Regular exercise has also been found to be beneficial in preventing AMD.
- Meibomian Gland Dysfunction: When the eyelid glands and the eyes and eyelids are all working normally, then you are not aware of your eyes on an hour by hour basis. When the normal function of the eyes is disturbed, then symptoms arise which cause you to be aware of your eyes on a daily, hourly or even minute by minute basis. When your eyes are constantly uncomfortable it is very difficult to concentrate on anything else.
The meibomian glands need to be functioning normally for maximum eye comfort. When the eyelid gland secretions become viscous, they cause plugging of the gland orifices and these plugs of solidified meibomian gland secretion prevent the normal sebaceous oily secretion from oozing out onto the free eyelid margins and prevent the lubricating action on the eye surface.
The meibomian glands run vertically in the eyelids, both upper and lower eyelids, and there are about 25-30 gland openings (orifices) on the edges of both upper and lower eyelids.
Meibomian gland dysfunction results in several symptoms. The main symptom is awareness of the eyes. This tends to occur with grittiness and a mild feeling of small bits of sand in the eyes. This is known as "foreign body sensation". Sometimes there are feelings of burning and soreness of the eyelid edges. Medically these glands are known as compound sebaceous glands and in the normal eyelid, the produce a secretion which lubricates the free edge of both upper and lower eyelids. The sebaceous meibomian gland secretion refreshes the eye surface with each blink, creating an optically perfect surface which is important for clear vision. This is known as the pre-corneal tear film and is a complex arrangement of three layers of different substances. Sitting on the front of the eye is a mucinous layer with a watery tear film layer on the surface of the mucin and then with the meibomian gland secretions as a sort of oily layer on the front of the water.
- Pinguecula (pin gwe' cue la) is a benign, yellowish growth that forms on the conjunctiva. They usually grow near the cornea on the nasal side. Pingueculae are thought to be caused by ultraviolet light and are most common among people who spend a great deal of time outdoors. This growth does not affect vision, but may cause irritation if it becomes elevated. In rare cases, the pinguecula may gradually extend over the cornea, forming a pterygium.
- Posterior Vitreous Detachment: The space between the crystalline lens and the retina is filled with a clear, gel-like substance called vitreous. With age, the vitreous thins and may separate from the back of the eye. This is called posterior vitreous detachment (PVD), a very common, usually harmless condition that the majority of people will not even realise has occurred. However some people notice flashes and / or floaters and this should always be attended to urgently because very occaisionally a retinal detachment can follow a posterior vitreous detachment but this is only likely to occur in the first few weeks following the initial symptoms.
- Pterygium is a raised, wedge-shaped growth of the conjunctiva. It is most common among those who live in tropical climates or spend a lot of time in the sun. Symptoms may include irritation, redness, and tearing. Pterygia are nourished by tiny capillaries that supply blood to the tissue. For some, the growth remains dormant; however, in other cases it grows over the central cornea and affects the vision. As the pterygium develops, it may alter the shape of the cornea, causing astigmatism. If the pterygium invades the central cornea, it is removed surgically. Since pterygia are most commonly caused by sun exposure, protecting the eyes from sun, dust and wind is recommended. Instilling artificial tears liberally is also helpful to decrease irritation. In some cases, steroid drops are prescribed to reduce inflammation.
- Retinal Detachment (see also floaters and / or flashes) occurs when the retina's sensory and pigment layers separate. Because it can cause devastating damage to the vision if left untreated, retinal detachment is considered an ocular emergency that requires immediate medical attention and surgery. It is a problem that occurs most frequently in the middle-aged and elderly. There are three types of retinal detachments. The most common type occurs when there is a break in the sensory layer of the retina, and fluid seeps underneath, causing the layers of the retina to separate. Those who are very short sighted, have undergone eye surgery, or have experienced a serious eye injury are at greater risk for this type of detachment. Short sighted people are more susceptible because their eyes are longer than average from front to back, causing the retina to be thinner and more fragile. The second most common type occurs when strands of vitreous or scar tissue create traction on the retina, pulling it loose. Patients with diabetes are more likely to experience this type. The third type happens when fluid collects underneath the layers of the retina, causing it to separate from the back wall of the eye. This type usually occurs in conjunction with another disease affecting the eye that causes swelling or bleeding.
- Subconjunctival Haemorrhage occurs when a small blood vessel under the conjunctiva breaks and bleeds. It may occur spontaneously or from coughing, heavy lifting, or vomiting. In some cases, it may develop following eye surgery or trauma. Subconjunctival hemorrhage tends to be more common among those with diabetes and hypertension. While it may look frightening, a subconjunctival hemorrhage is essentially harmless. The blood becomes trapped underneath the clear conjunctival tissue, much like a bruise. The blood is visible because it shows through the thin, clear conjunctiva. The blood naturally absorbs within one to three weeks and no treatment is required.