eyediology - opticians - london

Eye Conditions Explained

Common eye conditions


The eye focuses light onto the back of the eye, also known as the retina, firstly through the cornea and then through the lens. Normally light is refracted to produce a clear image on the retina. However if the curvature of the cornea or lens is not perfectly round then the amount of refraction may differ in different directions resulting in a slightly distorted image on the retina. If there is a different curvature in different directions this is known as astigmatism. The eye is sometimes described as being rugby ball shaped rather than football shaped. An optometrist can identify this problem and may recommend glasses to be worn if necessary.

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Acute infections of the eyelid—those that flare up with little or no warning—are irritating and can affect your vision. You may have symptoms such as itchy or burning eyes, blurred vision, gritty or granular sensations, or oily tears. These conditions are caused by either blepharitis, a medical term that means inflammation of the eyelid, or meibomianitis, inflammation of the oil-producing glands of the eye. Blepharitis is usually caused by Staphylococcus bacteria that thrive in excess oil produced by the glands of the eyelid.

Blepharitis sometimes accompanies outbreaks of acne. The essence of therapy is to prevent the infection from causing chronic symptoms or more serious problems. Depending on the severity of your symptoms, we may prescribe any or all of the following therapies:

  1. Warm or hot moist compresses applied to the eye.
  2. Eyelid cleansing procedures. Although neither this nor hot compresses are a cure for infection, both actions help remove debris that has become trapped in the glands and eyelashes.
  3. Manual expression of excess oil from the oil glands at the edges of the eyelids. Applying hot compresses before the expression usually helps the glands flow more freely and release trapped bacteria.
  4. In more severe cases we may prescribe antibiotic eye drops. These may or may not be in combination with a corticosteroid, an anti-inflammatory drug. Sometimes, instead of an antibiotic eye drop, antibiotic topical ointment is prescribed that should be applied along the edge of the eyelids. Oral antibiotics may also be used (a treatment usually reserved for special cases). Blepharitis can recur or remain chronic if not treated completely. Eyelid hygiene procedures are important in removing the bacteria that remain trapped in your lashes or lid areas of your eyes.

Directions for a Warm Soak of the Eyelids

  1. Wash your hands thoroughly.
  2. Moisten a clean washcloth with warm water.
  3. Close the eyes and place the washcloth on the eyelid for approximately 5 minutes OR better still us a Eye Bag
  4. Repeat several times daily.

Directions for an Eyelid Scrub

  1. Wash your hands thoroughly.
  2. Mix warm water and a small amount of shampoo that does not irritate the eye (e.g., baby shampoo).*
  3. Close one eye and use a clean washcloth (a different one for each eye) to rub the shampoo mixture back and forth across the eyelashes and the edge of the eyelid.
  4. Rinse with cool, clear water.
  5. Repeat on the other eye.

* If the eye becomes red or painful, consult an eye care professional immediately.

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Branch Retinal Vein Occlusion

Branch retinal vein occlusion (BRVO) occurs when blood flow in a vein is reduced or blocked which may result in reversible and sometimes irreversible loss of vision. It is normally a painless condition caused as a result of other conditions such as macula odema. People who smoke or have high blood pressure may be more likely to develop branch retinal vein occlusion.

If vision is affected, treatment with a laser may improve vision or reduce the risk of further vision loss. In most cases, we wait for spontaneous improvement. In BRVO, an artery crossing over the retinal vein at the point of obstruction is usually present. This can pinch the vein, like stepping on a garden hose, thereby cutting off blood flow. The area of the retina that drained through this vein may become congested or swollen. If patients see black floating spots in the field of view they are advised to seek emergency help from their optician or physician.

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A cataract is an opaque film or cloudiness that occurs in the lens within the eye. It may consist of varying size opacities and/or water vacuoles. In general, it is an alteration in the normal lens tissue that reduces its normal high degree of transparency. This, in turn, interferes with the degree and quality of light reaching the retina.


A patient with a cataract may experience any of the following symptoms: blurred vision, poor night vision, sensitivity to sunlight and halos around lights.

Risk Factors

Risk factors include radiation (sunlight and treatments), smoking, alcohol, medications, and genetics. The main cause of cataract is sunlight radiation. The sunlight tans the lens inside our eye much like it tans our skin. Whereas we get new skin cells on an average of every 26 days, the lenses inside our eyes have to last our entire lives. The energy in the sunlight, particularly ultraviolet radiation, causes the formation of unstable molecules called free radicals. These free radicals change the lens tissue, causing distortion and darkening. Cataracts can be directly or indirectly affected by medications and diseases. Many medications cause the pupil to dilate, allowing more harmful light into the eye. Examples are antidepressants, antihistamines, amphetamines, nitroglycerin, and beta-blockers. Other drugs, such as steroids and tamoxifen, can cause cataracts. Some drugs, like diuretics (commonly called water tablets), cause the tissue to be photosensitized, which results in increased sensitivity to sunlight. Medical conditions such as diabetes, hypertension, rheumatoid arthritis, and other connective diseases are commonly associated with cataracts.


Treatment includes eyeglasses, contact lenses, and surgery. New technologies in eyeglasses and contact lenses allow better vision. Ultraviolet radiation filters, non-glare technology, and the correction of higher-order aberrations with wavefront technology can result in better vision through cataract changes. The best preventive treatment for the progression of cataracts is polarized sunglasses with the addition of an antireflection coating on the backs of the lenses. Cataracts are generally not surgically removed until vision cannot be improved to reasonable levels with eyeglasses or contact lenses. The decision for having surgery usually depends on whether you can see well enough to do what you want to do. Phakoemulsification is a surgical technique used to allow small incisions sometimes not requiring any sutures. An artificial lens is implanted that may provide excellent vision without the need for strong glasses or contact lenses. Prognosis for good vision is excellent. Cataracts tend to progress at a slow pace and, as a rule, can be monitored on a yearly basis. At the appropriate time we can recommend surgery for your particular type of cataract. For the near future we should monitor your eye health status and cataract development on a regular basis.

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Lenses for Patients with Developing Cataracts

Our Optometrist and staff are pleased to be able to provide you the latest technology in eyeglasses. Summarized below are new improvements in technology and the benefits available to you.

If during the course of your examination we discover that you are showing cataract changes. Today’s lens technology allows us to prescribe glasses that will slow the development of your cataracts as well as improve your remaining vision. The eye’s lens tends to become cloudy with age. This prevents the lens from properly focusing light on the retina at the back of the eye, resulting in a loss of vision. The clouding results from chemical changes within the lens. Ultraviolet (UV) light and visible light can cause the lens to “tan,” much like tanning your skin.

Sun Lenses

The lens technology we have prescribed for you will block 100% of the most damaging light in the atmosphere. The tint recommended for you will block from 60% to 85% of the visible light necessary to see during daylight hours. Some tints are prescribed to allow normal color perception, and others are designed to increase contrast. The appropriate tint depends on the extent of your cataract changes and your personal needs. New lens technology also reduces the glare off surfaces such as roadways or reflections off water.

Lenses specifically designed to inhibit the progression of cataracts are manufactured from high-technology polymers, which are the least likely to break in case of an accident. The lens material is lighter, thinner, and the safest available.

Indoor Lenses

The clouding of the lens of the eye causes less light to reach the retina. New lenses allow nearly 10% more light to enter the eye. Thinner lens designs also result in more light reaching your retina. Newer lenses eliminate irritating reflections and improve contrast with high-technology tints and coatings. The additional light, loss of glare, and improved contrast will allow you to read more comfortably and see better when driving at night. These indoor lenses and sun lenses have properties that will provide you with better vision as well as protect you from the light rays contributing to the cataracts. Remember to wear your special sunglasses during all outdoor activities in the daylight. Try them on cloudy days and you may discover after a minute or so that you will adapt and see well with the sun lenses.

Our doctors and staff will continue to monitor new changes in lens technology that will benefit you. With today’s new lens technology and adherence to your doctor’s prescriptions, you can expect to see well the rest of your life. Thank you for the opportunity to provide you with your vision care. We look forward to seeing you in the future.

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Chalazia and Styes

The eyelids are a layer of skin which provides protection for the eye. When blinking, the eyelids help remove foreign objects and distribute tears, which lubricate your eyes and keep them moist. Two common conditions that affect your eyelids are chalazia and styes. A chalazion results from a blockage of one or more of the small oil-producing glands (meibomian glands) found in the upper and lower eyelids. These blockages trap the oil produced by the glands and cause a lump on the eyelid. These are usually relatively painless, but may appear red and cause some irritation when blinking. If the chalazion becomes infected, the eyelid can become swollen, inflamed, and more painful.

Styes are often confused with chalazia. Styes are infections or abscesses of an eyelid gland near an eyelash root or follicle. They generally occur nearer to the edge, or margin, of the eyelid than do chalazia, where they form a red, sore lump similar to a boil or pimple.

In some cases, both chalazia and styes may come to a head and drain on their own without treatment. However, in most instances they do not. A chalazion may be treated by applying hot compresses and/or antibiotic eye drops.* In some cases, steroid drugs may be injected into or adjacent to the site of the chalazion. A chalazion may also be treated by surgical incision and drainage when necessary. Sometimes oral medications are prescribed. Styes may also be treated with hot compresses.* frequently, antibiotic and/or steroid eye drops or ointments may be needed. Chalazia and styes most often respond well to treatment. If left untreated, however, they can be uncomfortable and unattractive and can lead to other problems. Chalazia and styes may recur. If this happens too frequently, your Optometrist may recommend additional tests to determine if other health problems may be contributing to their development.

Directions for Application of Hot Compresses

  1. Wash your hands thoroughly.
  2. Moisten a clean washcloth with hot water.*
  3. Close your eyes and place the washcloth on the eyelid for approximately 10 to 15 minutes.
  4. Remoisten the washcloth as necessary to keep it hot.
  5. Repeat at least four times a day.

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Conjunctivitis, commonly known as pink/red eye, is an infection of the thin membrane that lines the inside of the eyelids and the white part of the eye. The three most common types of conjunctivitis are viral, bacterial, and allergic. Each requires different treatments. With the exception of the allergic type, conjunctivitis can be contagious. The viral type is often associated with a cold or sore throat. Bacteria such as Staphylococcus and Streptococcus often cause bacterial conjunctivitis. The severity of the infection depends on the type of bacteria involved. The allergic type occurs more frequently among those with allergic conditions. When related to allergies, the symptoms are often seasonal. Allergic conjunctivitis may also be caused by intolerance to substances such as cosmetics, perfume, or drugs.


  • Watery discharge
  • Irritation or gritty feeling
  • Itching
  • Swollen eyelids
  • Swelling of the conjunctiva
  • Redness
  • Tearing
  • Mucous discharge that may cause the lids to stick together, especially after sleeping


Conjunctivitis is diagnosed during an eye examination with a biomicroscope. In some cases cultures are taken to determine the type of bacteria causing the infection.


The appropriate treatment for conjunctivitis depends on the cause of the problem. Eye drops can be prescribed in addition to non-steroidal anti-inflammatory medications, antihistamines and cool compresses. Sometimes an oral antibiotic or ointment is used to treat the condition. Like the common cold, viral conjunctivitis has no cure; however, the symptoms can be relieved. Viral conjunctivitis usually resolves within 3 weeks. To avoid spreading infection, take the following simple steps:

  • Disinfect surfaces such as doorknobs and counters with diluted bleach solution
  • Do not swim (some bacteria can be spread in the water)
  • Avoid touching the face
  • Wash hands frequently
  • Do not share towels or washcloths
  • Do not reuse handkerchiefs (tissues are best)
  • Avoid shaking hands

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Diabetic Retinopathy

Diabetes is a condition that can interfere with the body’s ability to use and store sugar. Diabetes can also, over time, weaken and cause changes in the small blood vessels that nourish the eye’s light-sensitive retina at the back of the eye where images are focused. This is called diabetic retinopathy. These changes may include leaking of blood, development of brush-like branches of the vessels, and enlargement of certain portions of these vessels. Diabetic retinopathy can seriously affect vision and, if left untreated, can cause blindness.

As diabetic retinopathy can cause blindness, early diagnosis and treatment are essential. We recommend having your eyes examined at least annually if you are a diabetic or if you have a family history of diabetes. To detect diabetic retinopathy, we look inside your eyes with an instrument called an ophthalmoscope. The interior of your eyes may also be photographed to provide more information and a record of the current state of your eyes. The beginning stages of diabetic retinopathy may cause blurriness in your central or peripheral (side) vision, or they may produce no visual symptoms at all. It mainly depends on where the blood vessel changes are taking place in your eye’s retina.

As diabetic retinopathy progresses you may notice cloudiness in your vision, blind spots, or floaters, which are usually caused by blood leaking from abnormal new vessels that block light from reaching the retina. In the advanced stages, connective scar tissue forms in association with new blood vessel growth, causing additional distortion and blurriness. Over time, this tissue can shrink and detach the retina by pulling it toward the center of the eye. Once diabetic retinopathy has been diagnosed, laser and other surgical treatments can be used to reduce the progression of this disease and decrease the risk of vision loss. If you have vision loss from diabetic retinopathy, we may prescribe special vision aids to help maximize your vision. Some of the optical aids available include telescopic lenses for distance vision, microscopic lenses, magnifying glasses, and electronic magnifiers for close work. Not every diabetic patient develops retinopathy, but the chances of getting it increase after having diabetes for several years. Evidence also suggests that factors such as pregnancy, high blood pressure, and smoking may cause diabetic eye disease to develop or worsen

As a diabetic or a person at risk for diabetes, you should take steps to help prevent the development of diabetic retinopathy, including the following:

  • Take your prescribed medication as instructed.
  • Follow a proper diet.
  • Exercise regularly.
  • Have your eyes examined regularly.

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Drusen are seen through the transparent retina as little yellow spots. They are essentially waste products of retinal metabolism that are present because certain structures surrounding the retina have developed a reduced capacity to process metabolic debris. This seems to be, for the most part, a normal process of growing older. Drusen generally develop in later years; however, exceptions exist. Drusen may or may not be related to a vision problem. However, they bear close watching because they can be related to some vision loss. The visual effect, if any, can be appreciated and demonstrated on the Amsler grid.

The first indication that drusen may present a problem is when you note a distortion in the grid pattern. The grid should appear perfect, with all the lines straight and parallel. If you note any distortion, voids, or wavy lines, notify us immediately. Remember, for the most part drusen are a normal change of growing older and probably will not develop into a problem. However, caution dictates that one should not leave such matters to chance.

Using the Amsler Grid

  1. If reading glasses are customarily worn, wear them.
  2. Test one eye at a time while closing the other.
  3. Look (concentrate) at the central dot and note the surrounding grid pattern. If the pattern is perfect, you have completed the test. If it is not perfect, mark the area of imperfection and notify us.

This daily test only takes a few seconds to perform.

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Dry Eye

The natural tears that your eyes produce are composed of three layers: the outer oily layer, the middle watery layer, and the inner mucous layer.

Dry eye is the term used to describe eyes that do not produce enough tears or that produce tears without the proper chemical composition in any of these layers. Dry eye is most often a result of the eyes’ natural aging process. Most people’s eyes tend to become drier as they age, but the degree of dryness varies, with some people having more problems than others. In addition to age, dry eye can result from the following:

  • Problems with normal blinking
  • Certain medications such as antihistamines, oral contraceptives, and antidepressants
  • Environmental factors such as a dry climate and exposure to wind
  • General health problems such as arthritis or Sjögren’s disease
  • Chemical or thermal burns to the eye

Dry eye symptoms are often different in different people, but the following are commonly experienced by those whose tear production is inadequate:

  • Irritated, scratchy, dry, or uncomfortable eyes
  • Redness of the eyes
  • A burning sensation of the eyes
  • A feeling of a foreign body in the eye
  • Blurred vision
  • Excessive watering as the eyes try to comfort an overly dry eye
  • Eyes that seem to have lost the normal clear, glassy luster

If untreated, dry eye can be more than just irritating or uncomfortable. Excessive dry eye can damage eye tissue and possibly scar the cornea, the transparent front covering of the eye, impairing vision. Contact lens wear may be more difficult because of the possibility of increased irritation and a greater chance of eye infection.

If you have the symptoms of dry eye, your optometrist can perform dry eye tests with diagnostic instruments to give a highly magnified view and special dyes to evaluate the quality, amount, and distribution of tears. Your optometrist will also need to know about your everyday activities, general health, medications you are taking, and environmental factors that may be causing your symptoms. In most cases dry eye cannot be cured, but your eyes’ sensitivity can be lessened and treatment prescribed so that your eyes remain healthy and your vision is not affected.

Possible treatments include the following:

  • Frequent blinking to spread tears over the eye, especially when using a steady focus for an extended period
  • Changing environmental factors, such as avoiding wind and dust and increasing the level of humidity
  • Using artificial tear solutions
  • Using moisturizing ointment, especially at bedtime
  • Administering cyclosporine immunomodulator drops

Other forms of treatment include the following:

  • Insertion of small plugs in the corners of the eyes to slow drainage and loss of tears
  • In rare cases, surgery

Whatever treatment is prescribed, you must follow your optometrist instructions carefully. Dry eye does not go away, but by working together, you and your optometrist can keep your eyes healthy and protect your vision.

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Floaters and Flashes


The small specks, “bugs,” or clouds that you may sometimes see moving in your field of vision are called floaters. They are frequently visible when looking at a plain background, such as a blank wall or blue sky. These visual phenomena have been described for centuries; the ancient Romans called them muscae volitantes, or “flying flies,” because they can appear like small flies moving around in the air. Floaters are actually tiny clumps of gel or cellular debris within the vitreous, the clear, jellylike fluid that fills the inside cavity of the eye. Although these objects appear to be in front of the eye, they are actually floating in the fluid inside the eye and cast their shadows on the retina (the light-sensing inner layer of the eye). Moving your eyes back and forth and up and down creates currents within the vitreous capable of moving the floater outside your direct line of vision.


The vitreous gel degenerates in middle age, often forming microscopic clumps or strands within the eye. Vitreous shrinkage or condensation is called posterior vitreous detachment* and is a common cause of floaters. It also occurs frequently in nearsighted people or in those who have undergone cataract operations or YAG laser surgery. Occasionally, floaters result from inflammation within the eye or from crystal-like deposits that form in the vitreous gel. The appearance of floaters, whether in the form of little dots, circles, lines, clouds, or cobwebs, may be alarming, especially if they develop suddenly. However, they are usually nothing to be concerned about and simply result from the normal aging process.

Are Floaters Serious?

The vitreous covers the retinal surface. Occasionally the retina is torn when degenerating vitreous gel pulls away. This causes a small amount of bleeding in the eye, which may appear as a group of new floaters. A torn retina can be serious if it develops into a retinal detachment. Any sudden onset of many new floaters or flashes of light should be promptly evaluated by your Optometrist. Additional symptoms, especially loss of peripheral or side vision, require repeat ophthalmic examination.

Flashing Lights

When the vitreous gel, which fills the inside of the eye, rubs or pulls on the retina, it sometimes produces the illusion of flashing lights or lightning streaks. You may have experienced this; it is usually not cause for worry. On rare occasions, however, light flashes accompany a large number of new floaters and even a partial loss or shadowing of side vision. When this happens, prompt examination by an optometrist is important to determine if a torn retina or retinal detachment has occurred. Flashes of light that appear as jagged lines or “heat waves,” often lasting 10 to 20 minutes and present in both eyes, are likely to be migraine caused by a spasm of blood vessels in the brain. If a headache follows, it is called a migraine headache. However, these jagged lines or “heat waves” commonly occur without a subsequent headache. In this case, the light flashes are referred to as ophthalmic migraine, or migraine without headache.

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Glaucoma is an eye disease in which the passages that allow fluid in the eye to drain become clogged or blocked. This results in the amount of fluid in the eye building up and causing increased pressure inside the eye. This increased pressure damages the optic nerve, which connects the eye to the brain. The optic nerve is the main carrier of vision information to the brain. Damage to it results in less information sent to the brain and a loss of vision.

The exact cause of glaucoma is not known and it cannot currently be prevented. It is one of the leading causes of blindness in the USA. But, if detected at an early stage and treated promptly, glaucoma can usually be controlled with little or no further vision loss. Regular optometric examinations are therefore important. People of all ages can develop glaucoma, but it most frequently occurs in the following populations:

  • Those older than 40 years
  • Those with a family history of glaucoma
  • Those who are very nearsighted
  • Diabetics
  • Afro-Caribbeans

Of the different types of glaucoma, primary open-angle glaucoma often develops gradually and painlessly without warning signs or symptoms. This type of glaucoma is more common among Afro-Caribbeans. It can cause damage and lead to blindness more quickly in Afro-Caribbeans, making regular eye examinations, including tests for glaucoma, particularly important for Afro-Caribbeans older than 35 years. Another type, acute-angle closure glaucoma, may be accompanied by the following symptoms:

  • Blurred vision
  • A loss of side vision
  • Appearance of colored rings around lights
  • Pain or redness in the eyes

Regular eye examinations are an important means of detecting glaucoma in its early stages and include the following:

  • Tonometry: a simple and painless measurement of the pressure in the eye
  • Ophthalmoscopy: an examination of the back of the eye to observe the health of the optic nerve
  • Visual field test: a check for the development of abnormal blind spots

Glaucoma can usually be treated effectively by eye drops or other medicines. In some cases surgery may be necessary. Unfortunately, any loss of vision from glaucoma usually cannot be restored. But, early detection, prompt treatment, and regular monitoring can enable you to continue living in much the same way as you have always lived. Protect your eye health and your vision; be sure to visit your Optometrist regularly.

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Headaches, The Eyes, and Vision

Headaches are a common symptom associated with the eyes and vision. They can be related to allergies, muscle strain, strained vision, glare, migraines, and eye disease.


The eyes are surrounded by several sinus cavities, which may become congested from colds or allergies. The tissue that lines the eyes is the same as that lining the sinuses. Your doctor will be able to recognize the signs of allergies in your eyes. People with headaches caused by allergies often wake up with them. Nearly 50% of the general population has allergies.

Muscle Strain

The eyes are controlled by six muscles on the outside and additional muscles inside. The outside muscles control eye movements and coordination. Difficulty using the eyes together often causes headaches, particularly during near tasks such as computer work. The muscles inside the eyes are used for focusing. A computer user changes focus an estimated 10,000 times during a 6-hour day. Our eyes were not made for this. Problems focusing commonly result in headaches and blurred vision.

Strained Vision

Many individuals can see well enough to get by but may notice a slight blur, or image overlapping  the clear image. Even small amounts of astigmatism can result in strained vision, making discrimination between the numbers 8, 3, and 5 difficult. Other times a person may simply be trying to read print that is too small or of poor contrast. Trying to decipher poor handwriting can result in headaches. The clearer the image, the more comfortable your vision will be.


Four types of glare make seeing comfortably difficult. Uncomfortable glare is caused by everyday bright light—outdoors even on cloudy days, indoors with overhead fluorescent lights. Disabling glare is caused by excessive light, as from a window on a bright day. Blinding glare comes from shiny surfaces such as computer screens, glass, metal, water, snow, or concrete. Distracting glare comes from reflections from eyeglass lenses without non-glare technology. Each of these can cause squinting, eye strain, and headaches.


Severe headaches are often thought to be migraine headaches by the general public. True migraine headaches are actually caused by the dilation of blood vessels in the brain. Usually the blood vessels constrict first, causing the vision part of the brain to get less oxygen and resulting in a strange vision phenomena. After approximately 20 to 30 minutes, the brain calls for more oxygen, dilating the blood vessels and causing the headache. Migraine headaches run in families.

Eye Disease

Many eye diseases may cause headache and discomfort. One type of glaucoma, conjunctivitis, iritis, and other inflammations of the eye can result in headaches. They are often associated with symptoms such as blurred vision, haloes around lights, and extreme sensitivity to light.

Your Optometrist will use several examination techniques to rule out vision and the eyes as a cause of your headaches. Treatment may include lenses, eye drops, oral medications, non-glare technology, eye exercises, or changes in the environment.

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Iritis is inflammation predominantly located in the iris, which is the colored part of the eye. The iris controls the size of the pupil, the opening that allows light into the back of the eye. It is located behind the cornea and just in front of the focusing lens of the eye.


  • Pain
  • Light sensitivity
  • Red eye
  • Tearing
  • Blurred vision
  • Floaters
  • Small pupil

Iritis is often associated with an infection or disease of another part of the body, including ankylosing spondylitis, reactive arthritis (Reiter’s syndrome), psoriatic arthritis, irritable bowel disease, Crohn’s disease, multiple sclerosis (HLA B15), sarcoidosis, systemic lupus erythematosus, Lyme disease, juvenile idiopathic arthritis, “cat scratch” disease, toxoplasmosis, toxocariasis, presumed ocular histoplasmosis syndrome, Whipple’s disease, valley fever, tuberculosis, leptospirosis, Rocky Mountain spotted fever, and others. Patients known to have these disorders should be examined for chronic mild iritis on a regular basis.


Iritis is diagnosed during an eye exam with a biomicroscope. Because iritis is associated with other diseases, blood tests, skin tests, and x-rays may be used to determine the cause of the inflammation. When the iris is inflamed, white blood cells are shed into the anterior chamber of the eye where they can be observed on biomicroscopic examination to be floating in the convection currents of the aqueous humor. These cells can be counted and form the basis for rating the degree of inflammation. This is measured on a scale of 1 to 4, with 4 being the most cells.


Initial treatment is through the use of topical corticosteroids. If adhesion is anticipated, then a dilating drop is used to relax the ciliary body to prevent the iris from adhering to the lens in a closed position. Iritis that is stubborn, recurrent, or chronic may require systemic treatment through the use of oral steroids or other immunomodulating drugs. Some of the consequences to the lack of treatment or undertreatment are epiretinal membrane formation, cystoid macular edema, cataracts, glaucoma, detached retina, vitreous hemorrhage, and vascularization of the retina. Uveitis is the third leading cause of preventable blindness in the developed world.

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A degenerative disorder of the cornea.  Structural changes occur within the cornea causing it to weaken and thin. As a result, the normal dome shape of the cornea gradually begins to develop a cone-like bulge. This leads to myopia and possibly astigmatism, resulting in distorted and overall reduced vision.

During the early stages, glasses or soft contact lenses can improve vision. However as the condition progresses, rigid contact lenses would be more appropriate. These would create a smooth surface over the cornea, allowing tears to flow more freely and so generally improving the health of the eye.

Keratoconus is normally diagnosed in early adolescence and may become more severe in the late 20s and 30s.


  • Decrease in quality of vision
  • Blurring of vision
  • Myopia begins to develop or increase
  • Increased sensitivity to light

Treatment: (the treatment aims to improve vision or halt further progression of keratoconus.)

  • Rigid contact lenses
  • Intacs intracorneal rings are sometimes inserted to improve contact lens fit.
  • Corneal collagen cross-linking – this attempts to stabalise the cornea (prevent further structural changes) and therefore prevent further progression of keratoconus.
  • Corneal Transplantation.

Risk Factors:

  • Diabetes has been shown to increase the severity of the condition.

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Macular Degeneration

Macular degeneration is the leading cause of central vision loss among older people. It results from changes to the macula, a portion of the retina responsible for clear, sharp vision that is located on the inside back wall of the eye. The macula is many times more sensitive than the rest of the retina; without a healthy macula, seeing detail or vivid color is not possible.

Macular degeneration has several causes. In one type, the tissue of the macula becomes thin and stops working well. This type is thought to be a part of the natural aging process in some people. In another, fluids from newly formed blood vessels leak into the eye and cause vision loss. If detected early, this condition can be treated with laser therapy, but early detection and prompt treatment are vital in limiting damage.

Macular degeneration develops differently in each person, so the symptoms may vary. Some of the most common symptoms include the following:

  • A gradual loss of ability to see objects clearly
  • Distorted vision; objects appear to be the wrong size or shape, or straight lines appear wavy or crooked
  • A gradual loss of clear color vision
  • A dark or empty area appearing in the center of vision

These symptoms may also indicate other eye health problems, so if you are experiencing any of these, contact your Optometrist immediately. In a comprehensive eye examination, your optometrist will perform a variety of tests to determine if you have macular degeneration or another condition causing your symptoms.

Unfortunately, central vision damaged by macular degeneration cannot be restored. However, because macular degeneration does not damage side vision, low vision aids such as telescopic and microscopic special lenses, magnifying glasses, and electronic magnifiers for close work can be prescribed to help make the most of remaining vision. With adaptation, people with macular degeneration can often cope well and continue to do most things they were accustomed to doing.

Remember: early detection of macular degeneration is the most important factor in determining if you can be treated effectively. Use an Amsler Grid as directed by your optometrist and maintain a regular schedule of optometric examinations to help protect your vision.

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Long sight occurs when light is focused behind the retina rather than on it, and the eye has to make a compensating effort to re-focus. This can cause discomfort, headaches or problems with near vision. Glasses may need to be worn all the time or just for close work, such as reading, writing or computer use. In older people, as re-focusing becomes more difficult, distance vision may also become blurred.

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Burn of the cornea by ultraviolet light (UVB). Also called radiation keratitis or snow blindness. The condition typically occurs at high altitudes on highly reflective snow fields or, less often, with a solar eclipse. Symptoms include tearing, pain, redness, swollen eyelids, headache, a gritty feeling in the eyes and temporary loss of vision.

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A pinguecula is a common, non-cancerous growth of the mucous membrane lining the eyeball and underside of the eyelids (conjunctiva).

A pinguecula appears as a small, yellowish lesion derived from the conjunctiva. It can appear on either side of the cornea, but usually appears on the nasal side. It may increase in size over many years. The cause is unknown, but chronic sunlight exposure and eye irritation may contribute to its development. Welding is a significant occupational risk. The main symptom is a yellow or white nodule on the conjunctiva near the cornea.

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Presbyopia is the loss of focusing ability that occurs naturally with age. In younger people, the lens is very flexible and the eye has a wide range of focus from far distance to close up. As you get older, the lens slowly loses its flexibility leading to a gradual decline in ability to focus on near objects. Presbyopia is not a disease but a normal and expected change which sooner or later affects everyone, whether you already wear glasses or contact lenses or not. Around the age of 40-45, you will begin to notice that you are holding the newspaper further away or need more light to read small print. There is no advantage in delaying using reading glasses, or changing to bifocals or varifocals; they will not make the eyes lazy. Your optometrist will advise you on the best form of vision correction to suit your individual lifestyle and occupation. Regular examinations are important throughout life, whether you are experiencing problems with your eyesight or not. Your optometrist will test your vision and, if necessary, prescribe glasses or contact lenses. They will also check closely for any early signs of eye disease or other medical conditions.

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Retinal Detachment

Retinal detachment occurs when the two layers of the retina become separated from each other and from the wall of the eye. The retina is like the film in a camera. Nerve cells in the retina detect light entering the eye and convert it into nerve signals to the brain.

Once the two layers of the retina, the sensory retina and the retinal pigment epithelium, lose contact with each other, the retina stops working properly because the eye cannot process what it sees. This causes vision loss in the affected area of the retina. Detachment always results in some vision loss, including severe loss or blindness


Retinal detachment may occur without warning. Symptoms include floaters in your field of vision and flashes of light or sparks when you move your eyes or head. Floaters and flashes do not always indicate retinal detachment, but they may be a warning sign and should be evaluated. If a flashing light occurs and does not go away within minutes, you should be examined immediately. The first sign of detachment may be a shadow or curtain effect across part of your visual field that does not go away, or new and sudden vision loss that gets worse over time.

Retinal detachment affects peripheral (side) vision first. Vision loss tends to get worse over time as more of the retina becomes detached, sometimes within a few hours or days. Once the detachment spreads to the center of the retina, vision loss becomes severe or even total. Surgery is needed to repair the detached retina to prevent permanent vision loss.


Retinal detachment is diagnosed by medical history and an examination of the eyes. If you have symptoms of retinal detachment, your Optometrist will examine your retina by using ophthalmoscopy. Ophthalmoscopy is a test that allows an optometrist to see inside the back of the eye with a magnifying instrument with a light source. This test enables the optometrist to see tears, holes, or detachment of the retina. Pictures may be taken to document the appearance of the retina.


Retinal detachment almost always demands urgent care. Without treatment, vision loss from retinal detachment can progress from minor to severe or total within a few hours or days. If discovered within 24 to 48 hours, comparatively simple laser surgery may restore good vision. If allowed to progress, the surgical techniques become much more difficult and the recuperation time longer, with a greater chance for permanent loss of vision.

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Retinitis Pigmentosa

Retinitis pigmentosa (RP) is one of a group of diseases that affect the retina of the eye. Some of the most common symptoms of RP include night blindness and loss of peripheral (side) vision.

Symptoms of RP often appear for the first time during childhood or adolescence. Stumbling over objects that seem to be in plain sight and clumsiness may be the first indications of a problem. The symptoms of RP generally worsen over a period of years. Although some patients with RP and advancing age may become blind, most will retain at least some vision and are classified as legally blind. Each individual case differs. RP develops inside the pigmented layer of the retina. The retina is a delicate layer of cells that acts like the film in a camera.

It picks up a picture and transmits it to the brain, where “seeing” actually occurs. Two types of cells in the retina that participate in sending visual messages to the brain are the rods and cones. The rod-shaped cells are mostly used to help you see “out of the corners of your eyes” (peripheral vision) and at night. The cone-shaped cells enable you to distinguish colors, see during the day, and help you see with your central vision. When RP begins, the rod-shaped cells begin to lose their ability to function. As a result, people with this condition frequently have trouble seeing at night or in areas of dim light. Poor or decreased night vision alone is not necessarily an indicator of RP, however. “Tunnel vision” is also a symptom of RP. The field of vision gradually narrows, giving the effect of constantly looking through a tunnel.

As RP progresses to an advanced stage, you may also have difficulty reading, distinguishing colors, and seeing distant objects clearly. This is caused by the deterioration of the cone-shaped cells. Your optometrist may be able to help you in maximizing your remaining vision by prescribing special low vision aids. Some of the optical aids available include telescopic lenses for distance vision, microscopic lenses, magnifying glasses, electronic magnifiers, night vision scopes, special filters, and field enhancers.

Unfortunately, although extensive research is being conducted, no treatment is available at this time to reverse the course of RP. However, early counseling by your optometrist can help you successfully adjust your lifestyle and career goals to this visual impairment. Potential problems can also be identified and forestalled by determining appropriate aids, training, and other job modifications in your chosen career field. When RP is diagnosed early, you can often take full advantage of educational and career guidance.

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Short sight occurs when light is focused in front of the retina causing distance vision to become blurred. Near vision, however, is usually clear. Short sight normallydevelops in childhood or adolescence, and is often first noticed at school. Glasses may need to be worn all the time or just for long distance, such as when driving, watching TV or sports.

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Subconjunctival Hemorrhage

A subconjunctival hemorrhage occurs on the surface of the eye. It is caused by a rupture of a small blood vessel under the conjunctiva, the transparent outermost protective covering of the eye. This allows blood to spread under this tissue, often causing a dramatic presentation. However, in the majority of patients it is of no consequence but may take several weeks to completely resolve or be reabsorbed into the vascular system.

Generally, physical exertion, straining, coughing, or sneezing may be responsible for a rupture of a small blood vessel under the subconjunctival area; however, frequently no cause can be identified. The standard recommended treatment is to apply cold compresses several times per day for 2 days to reduce any additional blood flow into the area followed by warm compresses to facilitate reabsorption. If subconjunctival hemorrhages reoccur two or more times in a year, vascular system disease must be ruled out.

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