Eye Conditions

Obtain a greater understanding of eye conditions with a comprehensive summary of all commonly-occurring eye conditions, from simple refractive errors such as myopia (short-sightedness) and hyperopia (long-sightedness), to more complex issues.

• Age-Related Macular Degeneration

  Age-related macular degeneration (AMD) is a disease, which affects the central part of the retina, the macula. The cells of the macula become damaged and this causes the gradual reduction of central vision. There are two types of age-related macular degeneration: wet and dry. ‘Wet’ macular degeneration develops the fastest and is the most aggressive form, whereas ’dry’ macular degeneration develops much more slowly and is also the most common form.

  AMD is an age-related process and is more common in people over 50 years old. ‘Wet’ macular degeneration is caused when new blood vessels grow behind the retina; this causes the build up of fluid and scarring, which destroys central vision. ‘Dry’ macular degeneration occurs over time when the cells in the macula simply stop working.

  The symptoms of AMD are that central vision appears blurred or distorted and eventually it may be lost completely, leaving a central scotoma - an area of diminished vision. Objects may take on abnormal sizes or shapes, for example straight lines may appear curved and the patient may also become sensitive to light.

  ‘Dry’ and ‘wet’ macular degeneration are treated differently as there is no treatment for ‘dry’ macular degeneration. However the condition may be alleviated by wearing glasses or the use of large text and bright lights, when looking at a detailed page or object. ‘Wet’ macular degeneration can sometimes be treated with laser treatment, if identified in the early stages. Another treatment to correct the ‘wet’ form is Photo Dynamic Therapy (PDT), which involves a dye called Visudyne being injected into the body. This dye lines the abnormal blood vessels in the retina and is then activated when light is shone onto the area. The activated dye then shuts off the abnormal blood vessels, which are causing the damage.

• Aniridia

  In Greek, aniridia literally means “without iris”. It is a condition where the iris is very underdeveloped. This can results in loss of vision and can cause other eye conditions, for example, cataracts and glaucoma.

  Aniridia is a genetic condition and is caused when the PAX6 gene, which is responsible for eye development, does not function properly.

  The symptoms of aniridia are an incomplete iris and therefore, a larger-than-average pupil, as the muscles which open and close the pupil, are missing. Another sign of aniridia is increased sensitivity to light.

  Aniridia cannot be treated, but certain factors of the condition can be improved, for example tinted glasses or contact lenses with an artificial iris may be used, to help protect the eye from the amount of light entering the large pupil. People with aniridia need to be regularly examined so that any conditions that occur because of the original disease are diagnosed quickly and dealt with appropriately.

• Aphakia

  Aphakia is a condition where the eye lens is absent. This results in over-exposure to ultra-violet light, as the lens normally absorbs UV light. This also causes a loss of accommodation, as the eye cannot adjust its focus without a lens.

  Aphakia can be caused when a cataract is surgically removed and an artificial lens is not implanted or by a wound or ulcer, or the condition may be inherited genetically.

  Symptoms may include the absence of a lens, a very deep anterior chamber or far-sightedness (hyperopia).

  Treatment for aphakia involves the insertion of an artificial lens (pseudo-phakia) or wearing strong convex contact lenses or glasses.

• Astigmatism

  Corneal astigmatism occurs when the cornea is irregularly shaped and lenticular astigmatism is when the lens is irregularly shaped. The most common astigmatism is corneal. Most astigmatic corneas have two curves, a steeper one and a flatter one, and this causes the light rays to focus at two points on the retina instead of only one.

  Astigmatism is usually a genetic condition, although it can be caused by scarring of the cornea due to an eye injury. Astigmatism can also be caused by eye surgery or keratoconus.

  Symptoms of astigmatism are blurred vision, headaches and squinting. These occur because the eye struggles to focus on images.

  Astigmatism can be treated with glasses, contact lenses, laser surgery or intraocular lenses. Toric contact lenses are soft and are made especially for correcting astigmatism.

• Blepharitis

  Blepharitis is a condition, which refers to the inflammation of the eyelids and can be either anterior or posterior. Anterior blepharitis affects the front of the eyelid and posterior blepharitis affects the inner eyelid.

  The causes of anterior blepharitis are staphylococcus infection and seborrheic dermatitis - a skin condition caused by irritation of the sebaceous glands. Posterior blepharitis occurs as a result of the dysfunction of oil glands under the eyelid. It can also be caused by acne rosacea - a condition that causes the blood vessels in the face to enlarge - and seborrheic dermatitis.

  The symptoms of blepharitis can include eyelid irritation, red and swollen eyelids, sensitivity to light and skin irritation. Blepharitis can also result in styes, which are an inflammation of the gland at the follicle of an eyelash and chalazion, which are small lumps on the eyelid.

  Treatment of blepharitis may include the application of warm compresses or lubricating ointments, which replace tears if the eyes are dry and sometimes even steroids, which are used to control inflammation. Blepharitis can also be controlled with eye hygiene and people with the condition are instructed to wash their eyelashes and eyelids regularly with warm water and/or diluted baby shampoo.

• Cataracts

  A cataract is the clouding of the eye’s natural lens, which occurs when protein accumulates in the lens and begins to block the light which is passing through.

  Many things can cause cataracts, the most common being age, and these are called age-related cataracts. Congenital cataracts appear in children and are inherited from the parents. Another form of cataracts are traumatic cataracts, which are caused by eye injuries, such as a hard blow or chemical burn. Diseases such as diabetes can cause cataracts to form and in this case, they are called secondary cataracts. Studies have been carried out which link smoking, poor diet, exposure to ultraviolet light and heavy alcohol consumption to the development of cataracts.

  Signs and symptoms of cataracts may include blurred vision, faded colour vision, sensitivity to bright light and halos.

  The recommended treatment for cataracts is surgery, which is very successful and can be performed if the patient’s daily life is being affected by the condition.

• Conjunctivitis

  Conjunctivitis, also known as pink eye, is the inflammation of the conjunctiva. This membrane is made up of tiny blood vessels and when these become irritated, they enlarge and the eye appears red in colour. There are four types of conjunctivitis: bacterial, viral, allergic and giant papillary. Each of these types has different causes and treatments.

  Bacterial conjunctivitis is caused by bacterial infections, such as staphylococcus and streptococcus. Viral conjunctivitis is often caused by the virus adenovirus, which is also associated with the common cold. Allergic conjunctivitis is usually caused by substance intolerance, such as pollen, house dust mites, mould or cosmetics. Giant papillary conjunctivitis may be caused by the introduction of a foreign body into the eye, for example a contact lens.

  The symptoms of conjunctivitis vary depending on the type. Bacterial conjunctivitis causes a swelling of the conjunctiva, redness, irritation, a gritty feeling and sticky eyelids in the morning. Viral conjunctivitis symptoms include irritation, redness of the eye, excessive watering and a watery discharge. Allergic conjunctivitis causes itching and redness of the eye, swollen eyelids, itching and production of tears from the lacrimal gland. Giant papillary conjunctivitis symptoms include itching, red bumps on the undersides of the eyelids and a heavy discharge.

  Bacterial conjunctivitis can be treated with antibiotics which will alleviate the symptoms and aid healing, whereas viral conjunctivitis cannot be treated and will normally clear up within a few days. However, symptoms can be alleviated with cool compresses. Treatments for allergic conjunctivitis are antihistamines, cool compresses, and artificial tears. Giant papillary conjunctivitis will require prescribed medication that will reduce the inflammation.

• Corneal Abrasion

  Corneal abrasion is the medical term to describe damage to the cornea due to minor trauma. The damage could be a scrape, scratch or a foreign body embedding itself in the eye.

  Corneal abrasion is anything that causes damage to the cornea, for example when an object such as a finger is accidentally poked in the eye or when smaller particles such as sand are blown into your eye by the wind.

  Symptoms of corneal abrasion are blurred vision, sensitivity to bright lights, tearing of the eyes from the lacrimal gland, the feeling that there is something in your eye and squinting.

  Treatment is normally with antibiotics to prevent infection, eye-drops for pain relief and sometimes, a bandage contact lens, for added pain relief. Before bandage contact lenses were invented, pressure patch eye-pads were used. If corneal abrasions are not treated effectively or if the injury does not heal properly then recurrent corneal erosion may occur.

• Corneal Edema

  Corneal edema is a condition in which the cornea swells. This is because the inside layer of the cornea becomes damaged and fluid starts to accumulate within it. This over-hydration results in corneal edema.

  Corneal edema can be caused by many things, but is usually as the result of other eye conditions. For example corneal edema may be caused by Fuch’s endothelial dystrophy, glaucoma, keratitis, trauma and over-wearing of or ill-fitting contact lenses. Corneal edema may also be a congenital condition.

  Symptoms could include, blurred vision, blister (bullae) formation, halos around light sources and pain.

  Treatment of corneal edema requires hypertonic eye-drops, which draw liquid out of the cornea, or a corneal transplant. Another treatment is tarsorrhaphy, where the upper and lower eyelids are partially sewn together to narrow the opening of the eye and prevent further damage.

• Corneal Ulcer

  This condition is also known as acanthamoeba keratitis and is the inflammation or infection of the outer layer of the cornea.

  Corneal ulcers are most commonly caused by an infection of acanthamoeba – which is a water-borne parasite. Other infections can be bacterial, viral or fungal. Other causes of corneal ulcers are disorders that prevent the eyelid from closing, dry eyes or are the result of chemical burns.

  Symptoms of corneal ulcers are tearing (see above), discharge, redness of the eye, sensitivity to light, blurry vision and a white spot on the cornea.

  Treatment of corneal ulcers are as follows: bacterial - use antibiotics; fungal - use anti-fungal agents and for viral - use anti-viral preparations. Pain relief can also be prescribed.

• Cystoid Macular Edema

  Cystoid Macular Edema is a condition where fluid-filled cystoids appear on the central part of the retina and macula, which causes swelling.

  The most common cause is previous eye surgery such as for cataracts, but it can also be caused by inflammation of the eye, for example, by uveitis.

  Cystoid macular edema symptoms are blurred central vision - as it is the macula, which gives central vision - distorted and pink-tinted vision, and sensitivity to light. The condition is normally treated with anti-inflammatory eye-drops or laser surgery, which extracts fluid from the eye.

• Diabetic Retinopathy

  Diabetic retinopathy is a condition that may be caused by diabetes. There are two stages of diabetic retinopathy, the first of which is called the background stage. This is where blood vessels in the retina become weakened and leak, which leads to retinal edema (swelling). The second stage is called the proliferative stage and this is where new blood vessels develop, to maintain the oxygen levels.

  Diabetes causes retinopathy, as high blood sugar levels cause the blood vessels in the retina to leak fluid or bleed, and this causes the retina to swell.

  Symptoms of diabetic retinopathy are sudden loss of vision, blurred vision, flashes, floaters and retinal bleeding.

  Diabetic Retinopathy can be treated by a surgical procedure of scatter laser treatment. This is used to condense the abnormal blood vessels, which seals them and prevents the production of new blood vessels. A vitrectomy operation is needed when patients with diabetic retinopathy bleed into their vitreous humour.

• Diplopia

  Diplopia, also known as double vision, is where a single object is perceived as two images.

  There are a variety of different causes, including those that induce short-term episodes and others that induce long-term diplopia. Double vision that only appears for a short period of time may be caused by over-consumption of alcohol or being excessively tired. The long-term condition is much more serious and may have many causes. For example cataracts may cause diplopia, as the clouding of the lens causes light rays to scatter, which could result in numerous images. Double vision could also be caused by strabismus (a misalignment of the eyes), a brain tumour or head injury, refractive surgery, keratoconus or corneal dystrophies.

  Symptoms of diplopia include double vision and the appearance of misaligned eyes.

  Treatment of diplopia may comprise of eye exercises, vision therapy, prisms in glasses or if cataracts are the cause, then surgery. Diplopia must be treated in children to prevent it from developing into amblyopia, which is also known as a ‘lazy eye’, as this decreases vision in one or both eyes. In adults, diplopia should be investigated immediately, as an underlying cause of double vision could be a tumour or aneurysm, which would need to be treated urgently.

• Far-sightedness

  Please see Hyperopia.

• Glaucoma

  Glaucoma is a condition of the eye, which is caused by increased intraocular pressure (IOP). This results in damage to the optic nerve and consequent vision loss.

  Causes of glaucoma may include diabetes, eye surgery, myopia, tumours, uveitis and cataracts. There are other factors that could increase your risk of having the condition, and they include age, family history of glaucoma and poor health.

  The most common type is open-angle glaucoma, which has no symptoms and hence is very dangerous, as vision loss is sudden and permanent. Close-angle glaucoma is less common and has noticeable symptoms, so can be treated quickly. These symptoms include extreme pain in one eye, headaches, sensitivity to light, vision halos and nausea. Glaucoma in children is recognisable by misty, white, enlargement of the cornea and sensitivity to light.

  Routine eye examinations are recommended, so that glaucoma can be detected early and treated. Treatment includes medicine to decrease the production of vitreous humour and laser treatment or surgery if medical or laser treatments do not decrease the intraocular pressure within the eye successfully.

• Hyperopia

  Hyperopia is also known as long-sightedness or far-sightedness and is a condition whereby the light entering the eye forms images behind the retina, instead of focusing on it.

  There are two causes of hyperopia, the cornea of the eye may be too flat or the length of the eye may be shorter than average. This is fairly common in children, but many of them grow out of it. The condition affects young adults less than older people, as their lens can accommodate more efficiently and focus on the image. However, as a person ages, their lens is less elastic and cannot accommodate as well, so hyperopia becomes more apparent.

  Symptoms of hyperopia include headaches, squinting, eyestrain or the feeling of fatigue when working with objects or carrying out tasks that are close to the eye.

  Treatments of hyperopia may be glasses or contact lenses to correct the far-sightedness, laser vision correction or refractive eye surgery.

• Hypertropia and Hypotropia

  Hypertropia is a form of strabismus where one eye has deviated higher than the other. Hypotropia is a similar condition, however in this case one eye has deviated lower in comparison to the other. Both conditions are caused by differences in the intraocular muscles.

  Hypertropia can be acquired or congenital. The causes of acquired hypertropia are trauma induced by eye surgery or the result of other conditions, for example Brown’s or Duane’s syndromes.

  For hypertropia, glasses are used to correct refractive errors, patching can be used and eventually surgery may be used to treat the condition by re-aligning the eyes.

• Hyphema

  Hyphema is a condition, which describes the collection of blood in the anterior chamber of the eye. This occurs when blood vessels in the iris leak into the aqueous fluid. Hyphema may partially block vision.

  The cause of hyphema is normally blunt trauma to the eye, but it can be a result of a surgical procedure or a spontaneous occurrence.

  Symptoms of hyphema include a visible pool of blood in the eye, eye pain, decreased vision, increased intraocular pressure and sensitivity to light.

  Allowing the blood to reabsorb naturally normally clears hyphema but care must be taken not to make the bleeding worse. Therefore bed rest and avoidance of strenuous activity is prescribed, together with eye patches and eye drops. If hyphema does not disappear or gets worse, then the blood is irrigated from the anterior chamber by a surgical procedure.

• Hypotony

  Hypotony is when the eye has a low intraocular pressure.

  The main causes of hypotony are often associated with surgical procedures such as cataract surgery and glaucoma filtration (trabeculectomy). However inflammation within the eye and both retinal and choroid detachment can cause hypotony.

  Symptoms of hypotony include decreased vision and mild pain.

  Surgery induced hypotony is normally treated through patching, injecting blood in the eye to prevent scarring, drainage of the fluid external to the choroid, or using viscoelastics, which reshapes the front inner part of the eye. Retinal detachment is dealt with surgically and inflammation is treated with corticosteroids.

• Keratoconus

  Keratoconus is a condition of the eye in which the corneal tissue thins and then starts to bulge forwards, creating a conical shape of the cornea instead of a gradual rounded one.

  There is no known cause for keratoconus; however, there are certain factors, which are associated with the condition. For example, overexposure of sunlight and ill fitting contact lenses, could all contribute to the disorder. Another view is that keratoconus is genetic, as the condition can reappear in extended families.

  The symptoms of keratoconus include blurred and distorted vision, sensitivity to light and headaches from straining the eyes.

  Soft contact lenses or eyeglasses are used to treat mild keratoconus, but when the disorder progresses, other treatments may be required. For example, soft contact lenses would be replaced with rigid gas permeable contact lenses as they are stronger and firmer, to re-shape the irregular cornea. Eye drops, which contain riboflavin, can also be used as they strengthen the corneal tissue. Finally, the last treatment to be considered is a corneal transplant, for patients who cannot tolerate rigid gas permeable contact lenses and other treatments are not successful.

• Marfan's Syndrome

  Marfan's syndrome is a genetic disorder, which affects the connective tissue, characterised by abnormalities of joints, bones and tendons. Another result of Marfan’s syndrome is that the eye is elongated, which causes high myopia and the lens moves upwards and outwards.

  Symptoms of Marfan's syndrome are reduced vision, diplopia, retinal detachment and glaucoma.

  Contact lenses and glasses are used to treat eyes affected by Marfan's syndrome and surgical procedures may be required if the lens dislocates.

• Myopia

  Myopia, also known as near-sightedness, is a condition where light rays which have entered the eye, focus in front of the retina instead of directly on it.

  There are two causes of myopia, the first is that the eyeball is slightly longer than normal and the second is that the cornea is too steep, and therefore light rays focus in front of the retina. Myopia is hereditary.

  Symptoms of myopia include eyestrain, headaches, clearer vision when squinting and fatigue when concentrating on objects which are long distance, e.g. when driving.

  Treatment for myopia may be corrective glasses, contact lenses or even refractive surgery.

• Near-Sightedness

  Please see Myopia.

• Pink Eye

  Please see Conjunctivitis.

• Posterior Capsular Opacification

  Posterior capsular opacification is a condition in which lens cells grow over the back of an intraocular lens, which has been implanted during cataract surgery.

  The causes of posterior capsular opacification result directly from cataract surgery, when the eye’s natural lens is removed from the lens capsule and replaced with an intraocular lens. Around 20% of people who have had cataract surgery will develop posterior capsular opacification.

  The symptoms of posterior capsular opacification are very similar to those of cataracts. There is a gradual loss of vision, blurred vision and lights might give more glare than they normally would.

  Treatment is very simple and is a non-surgical procedure known as YAG posterior capsulotomy. In this procedure, a YAG laser will be used to make a small opening in part of the capsule to allow light to pass directly to the back of the eye again. Patients will notice results immediately and the procedure is quick and painless.

• Posterior Vitreous Detachment

  Posterior Vitreous Detachment is a condition in which the vitreous humour detaches from the retina, as it shrinks.

  The condition occurs when people age, as the vitreous changes with age. The central part becomes more liquid and the outer part peels away from the retina.

  The symptoms of posterior vitreous detachment include floaters (pigment from the retina floating in the vitreous) (didn’t define ‘floaters’ earlier in article) and flashing lights (which are caused when the pull of the vitreous stimulates the retina and the brain interprets these stimulations as light).

  Unfortunately there is no treatment for posterior vitreous detachment and patients usually adapt to the floaters and flashing lights.

• Presbyopia

  Presbyopia is an age-related condition that causes the inability of the lens to focus upon objects as they are moved closer to the eye.

  Presbyopia is caused through the aging process as the lens becomes less flexible and cannot change shape as easily. This results in the inability of the eye to accommodate and focus on near objects. The exact reason why the lens hardens is still under debate.

  The main symptom of presbyopia is difficulty reading text up close and therefore, holding reading material at arm’s length. Other symptoms include eye fatigue when doing near tasks and headaches, as well as difficulty reading in dim light or when you are tired.

  Presbyopia is treated through bifocal eyeglasses, multifocal contact lenses or simply reading glasses when you are doing tasks near to the eye.

• Recurrent Corneal Abrasion

  Recurrent corneal abrasion is a condition in which epithelial cells on the cornea adhere poorly to the basement membrane and become displaced easily.

  This condition occurs as a result of the incomplete healing of a previous corneal injury (see corneal abrasion) or corneal dystrophy.

  Symptoms of recurrent corneal abrasion include intense pain and tearing (see above) upon wakening, sensitivity to lights, blurred vision and red eye.

  Initial treatment of recurrent corneal abrasion is with antibiotic cream and the use of an eye pad, so that the cornea can heal without the eye blinking and hindering the process. Therapeutic contact lenses may also be considered to prevent abrasion during blinking and some patients may benefit from laser phototherapeutic keratectomy (PTK), which removes the external layer of corneal cells.

• Red Eye

  Red Eye, or subconjunctival haemorrhage, is a condition that occurs when a blood vessel under the conjunctiva breaks and bleeds, turning the sclera red.

  A subconjunctival haemorrhage can be spontaneous or caused by a sudden blow to the eye, an eye injury, sneezing or coughing, which causes the blood vessels to rupture.

  Red eye is painless and vision remains exactly the same, so the only symptom is the appearance of a red spot on the white part of the eye.

  There is no treatment for a subconjunctival haemorrhage as it is not harmful. The eye will reabsorb the blood naturally between one and three weeks. If red eye recurs however, you should see a doctor to make sure that it is not occurring due to high blood pressure or blood clotting problems.

• Retinal Detachment

  Retinal detachment occurs when the retina’s sensory layer peels away from the support layer. This means that the brain cannot construct a precise image from the signals being received from the damaged retina.

  The condition can be caused spontaneously, through trauma or because of diabetes. Retinal detachment can also occur as a result of posterior vitreous detachment.

  Symptoms of retinal detachment include flashes of light, a decrease in vision, central vision loss and floaters.

  Pneumatic retinopexy is a procedure, which can treat retinal detachment, and is carried out under local anaesthetic. This procedure involves injecting a small gas bubble into the vitreous, which rises up and presses against the part of the retina, which has peeled away. This allows the sensory layer of the retina to seal with the underlying layer. In addition to pneumatic retinopexy, cryotherapy can be performed, which uses nitrous oxide to fix the retina in place. Another surgical procedure, which can be used to treat retinal detachment, is called scleral buckle surgery. This attaches a silicone band to the outside of the eyeball, pushing the wall of the eye against the hole in the retina, thus holding the retina in position and allowing it to re-attach. The final procedure is a victrectomy, in which some of the vitreous humour is removed, and replaced with a gas bubble or silicone oil to reattach the retina.

• Subconjunctival Haemorrhage

  Please see Red Eye.

• Uveitis

  Uveitis is a condition that affects the uvea, which is the middle layer of the eye. The uvea consists of the iris, ciliary body and choroid and any inflammation of the uvea is called uveitis. Uveitis is classified in different ways depending on the location of the inflammation within the eye. Anterior uveitis affects the iris or ciliary body and is the most common type. Intermediate uveitis affects the area behind the ciliary body and part of the edge of the retina and is the second most common type. Finally, posterior uveitis affects the choroid and is the least common type.

  Uveitis can be caused by infection from a virus or fungus or it may be due to a parasite. Trauma can also cause uveitis, but many causes are unknown.

  The symptoms of uveitis depend on which type it is. Anterior uveitis includes sensitivity to light, blurred vision, pain, tearing (see above) and redness around the pupil. Intermediate uveitis includes blurred vision and floaters, while posterior uveitis includes blurred visin and pain.

  Glucocorticoid steroids are normally used to treat uveitis, as these anti-inflammatory drugs suppress the immune system and reduce inflammation and irritation. Eye drops are also used to treat anterior uveitis and reduce inflammation.

As with all the research we provided please consult your Doctor or Optician before taking any medical action!