Information for Patients

Eye Conditions

Age-Related Macular Degeneration

Age-related macular degeneration involves the deterioration of the macula: a small space in the centre of the retina concerned with distinguishing detail. Therefore, the main symptom of AMD is an inability to clearly see details in your central vision, both from a distance and close-up. Your peripheral vision, however, is not affected. There are two forms of AMD: dry or late (wet). Dry is most common, accounting for 75% of cases, and results after excess matter accumulates under the macula and the retina becomes thinner and weaker in the area it overlaps with the macula. Currently, there is no cure for this form of AMD. Late AMD can occasionally develop from early AMD, and is a more serious form of it. The most common form of late AMD is ‘wet’, and develops after the retina is damaged from atypical blood vessel growth that go on to leak blood and fluid. Permanent loss of central vision can occur, however going completely blind is unlikely as peripheral vision is still intact. Unlike early AMD, late AMD can be treated. The most effective treatment is to have intravitreal injections of ranibizumab continually throughout the year, which can prevent the atypical blood vessels developing, and so their leakage can no longer damage the retina. Early detection of a problem is key in its treatment. 
If you are concerned that you may have AMD, please contact St John.


Cataracts are a relatively visible condition, where the eye’s lens clouds over and causes vision to slowly but progressively become blurred and indistinct. There are many different forms and causes of cataracts, with the most common being age-related (after the patient is 40 years old) and simply occurs as a by-product of a person aging. However, cataracts can also occur from birth (see Congenital Cataracts) or due to some form of trauma to the eye. The treatment for cataracts is replacing the cloudy lens with a clear one through surgery, and mainly only occurs when the cataract is disrupting your ability to carry out your usual, everyday life.
If you are concerned that you may have a cataract, please contact St John.  

Congenital Cataract

Congenital cataracts are cataracts present from birth, where the lens is the eye is partially or fully clouded over. This causes the child’s sight to become blurred, especially when the cataract is concentrated on the centre of the lens. Cataracts may occur in one or both eyes, and if it occurs in only one then it may lead to amblyopia (a lazy eye). If the cataract is too dense and is left untreated, it can cause blindness at a young age. However, if it is only a mild cataract, it will probably be left untreated. When a doctor believes the cataract is interfering too much with the child’s vision, they may propose surgery to remove clouded lens and replace it with a clear lens. Afterwards, the child will most likely have to wear glasses suited to their new lens but will have an overall good standard of vision.
If you are concerned with your child’s congenital cataract, please contact St John

Corneal Abrasion

Corneal abrasions are where the cornea gets scratched, usually following from some form of damage to the eye, whether that be from getting dirt in the eye, scratching it with a nail or using contact lenses. These abrasions will be extremely painful, and may take up to 48 hours to heal. During this time, your vision may be affected and your eye may also become more sensitive to light. Ointment may be prescribed by a doctor to deal with the injury, who will give instructions on how to properly use it, and the eye should not be touched or have a contact lens placed in it. However, if the eye is still painful after the ointment use then a doctor should be contacted.
If you are concerned with having a corneal abrasion, please contact St John

Diabetic Retinopathy

Diabetic retinopathy results from the retina’s blood vessels becoming damaged due to diabetes, and is extremely common in those who have suffered with diabetes for over 10 years. Diabetic retinopathy is usually diagnosed during a regular eye check-up, however if your vision becomes blurry and indistinct, medical advice should be sought as soon as possible. Two forms of diabetic retinopathy can lead to the significant deterioration of sight: proliferative diabetic retinopathy (PDR) and diabetic macular oedema (DMO). PDR causes the retina’s surface to develop extremely delicate blood vessels that damage easily and bleed into the eye, possibly resulting in the retina scarring or even detaching itself. DMO forces the tissue of the retina to swell because of fluid leaking from impaired blood vessels and can cause blurred central vision, meaning the patient is unable to carry out some everyday activities. DMO can be treated through injections of bevacizumab or ranibizumab, or even through laser photocoagulation, where the blood vessel leakage is reduced to stop vision from further deteriorating. 
If you are concerned about possibly having diabetic retinopathy, please contact St John.


Glaucoma, one of the most common causes of blindness, comes about due to damage to the place that the optic nerve leaves the eye. This damage is usually caused from there being too much pressure within the eye on the nerve. Since there are normally no symptoms for glaucoma, the most effective way to discover it is through regular eye check-ups. Glaucoma comes in four main forms: the most common, primary open angle glaucoma, and the more uncommon angle closure glaucoma (a more abrupt and painful type), secondary glaucoma (as a result of other eye-related trauma or disease), and developmental glaucoma (which exists from birth). Loss to vision due to glaucoma is irreversible, however an early diagnosis and frequent medical care can prevent vision from deteriorating further. 
If you are concerned that you may have glaucoma, then please contact St John


Keratoconus occurs after the cornea gradually becomes thinner, with cone-shaped swelling beginning to form.  This swelling means the eye’s vision deteriorates as the eye is unable to correctly focus. Keratoconus is a slow, progressive disease that usually occurs in young adults. When it is first diagnosed, treatment is in the form of wearing glasses or contact lenses, but once the cornea becomes too thin, rigid gas permeable (RGP) contact lenses are a more effective solution. If the RGP contact lenses are not effective in correcting vision, then a corneal transplant can occur.
If you are concerned that you may have keratoconus, then please contact St John.

Strabismus (squint)

When a squint occurs, the eyes are misaligned, and so one will point in a different direction to the other. There are two main types of squint: convergent (eye turning inwards) or divergent (eye turning outwards). Squints frequently occur in children below the age of five, and, if left untreated, can lead to amblyopia (a lazy eye) or double vision. It is important that amblyopia is treated before the age of seven, so if you believe your child has a squint then seek medical advice soon. Squints can, however, also occur in adults although this is less common. Squints are mainly treated through glasses, but may also require surgery in some cases to correct the eyes.
If you are concerned that you or your child may have a squint, please contact St John.

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