The cornea is the ‘window’ to the outside world. It is a clear, curved structure with considerable strength. The function of the cornea is to allow transmission of light into the eye and help to focus the light near to the retina.
Any problems within the cornea can lead to symptoms of blur due to either a lack of transparency or due to an irregular shape. Pain can be associated with corneal disease.
Corneal pathology can be from a variety of factors but the most common diseases are listed below.
Irregular bulging of the cornea and distorted vision.
What is Keratoconus?
Keratoconus is an eye disease that causes the central area of the cornea to become weak and thinner, making the shape ‘bulge’ in an irregular manner. This results in a refractive error with the end result being distorted vision. The cornea is the transparent dome-shaped front part of our eyes, allowing for focusing of the eye. To function properly it must be smooth and appropriately shaped.
Although it can begin at any age, keratoconus often starts during puberty and progresses over time until it stabilises, many years later. It is estimated to affect 1 person in 2000. Therefore keratoconus is not uncommon.
Keratoconus is usually first diagnosed in the form of an Astigmatism, where the cornea is seen to bulge slightly, which in turn, will impair the eyes’ ability to focus. However, for some patients keratoconus will progress to the point where vision is impaired such that glasses or contact lenses cannot improve the vision further. Although often only one eye is noticeably affected, it is common for both eyes to be affected.
There are many treatment options for patients diagnosed with Keratoconus. Your consultant surgeon can expertly guide you through the best treatments for you.
Herpes Simplex Keratitis (HSK)
Eye pain, watering and redness. The localised infection can often be treated very effectively but if it is left untreated, it can cause permanent damage to the vision.
What is Herpes Simplex Keratitis (HSK)?
Herpes Simplex Keratitis (HSK) is an infection of the cornea caused by the Herpes virus.
The virus is present in over 99% of the population and lives within the host indefinitely as there is no way to eradicate the virus completely. In some people, the virus will cause an infection of the cornea which initially presents with pain, watering and redness.
This is a clinical diagnosis made by examination. Sometimes, doctors can perform swabs to test for the presence of this virus.
The virus itself cannot be eradicated so recurrences are treated as and when they occur. However, if attacks are frequent, then treatment can be given to reduce the episodes in order to reduce the risk of damage and improve quality of life.
Fuch’s endothelial dystrophy (FED)
In the early stages of the condition, vision tends to be blurred on waking in the morning. This clears often in an hour or two. This occurs as the cornea is normally thicker in the morning, and it retains fluids during sleep that evaporate in the tear film while we are awake. But as the dystrophy worsens, this swelling will remain constant and reduce vision for longer and eventually blurred vision remains throughout the day. In the most severe cases the cornea forms blisters that can cause pain.
What is Fuchs’ Endothelial Dythrophy?
Fuch’s endothelial dystrophy (FED) is a slowly progressive disease. There is a slow loss of endothelial cells from the inner layer of the cornea. If the number of cells drops below a critical density the cornea will begin to become cloudy and blur the vision. Although early signs of the dystrophy can be seen in people of their 30s and 40s, the disease rarely affects the vision until the person reaches their 60s or later. Happily, many patients may have microscopic signs of FED without ever having any significant visual symptoms.
Fuchs dystrophy occurs when endothelial cells (the back layer of the cornea) gradually deteriorate without any apparent reason. With time the endothelial cells are lost, preventing the cornea from effectively pumping water out of the stroma (middle layer of the cornea). This causes the cornea to swell and distort vision. Eventually, the epithelium (front layer of the cornea) takes on water, resulting in blisters which can cause pain and severe visual impairment.
FED is often diagnosed by the optometrist or ophthalmic surgeon in the very early stages. A characteristic pattern in the inner layer of the cornea can be seen under the microscope. This can often be diagnosed many years before visual symptoms develop.
Monitoring can be by watching for the visual symptoms such as blurred vision in the mornings. Measurements in the clinic can be performed. The corneal thickness can be measured. The thickness will increase as the condition deteriorates. The density of cells can be monitored using an endothelial cell counter.
The early stages do not require treatment. There is unfortunately no known way of preventing the condition from deterioration. However, many patients deteriorate very slowly and often do not suffer any significant visual deterioration. Some cases may improve using ointments to reduce the swelling, or by the use of a hair dryer, held at arm’s length or directed across the face to dry out the cornea or the blisters if they are very uncomfortable.
In more severe cases when the disease starts limiting one’s lifestyle by making daily living more difficult, a corneal transplant may be considered to restore sight. Your consultant surgeon can expertly guide you through the best treatments for you.
Recurrent erosion syndrome
Patients typically report attacks of mild to severe eye pain, redness, tearing, and light sensitivity. Some patients may report blurred vision. Most patients report symptoms after awakening from sleep. During rapid eye movement (REM) sleep, the eyelids contact the moving cornea leading to abrasions, which present the symptoms listed above. A small proportion of patients report pain after trying to open their eyes in the morning.
What is Recurrent Erosion Syndrome (RES)?
Recurrent erosion syndrome (RES) refers to repeated episodes of superficial, spontaneous abrasions leading to eye pain. Erosions are “scratches” on the surface of the cornea, the clear portion of the eye overlying the iris and the pupil. In many cases, the cells of the outer layer of the cornea are loosely attached to the underlying tissue. These cells spontaneously slough leading to recurrent erosions. Most episodes occur without an identifiable precipitant. RES remains a common and often under diagnosed condition that can have a great impact on the quality of life for patients.
RES typically occurs in eyes that have suffered from an abrasive injury such as from a fingernail or paper cut. The area heals initially, but is prone to recurrent erosions in the future. Some patients may have an underlying corneal dystrophy that predisposes to RES.
The treatment of recurrent erosion syndrome is often inadequate, with many patient suffering with symptoms for years. The surgeons can perform the most effective treatment with the aid of the excimer laser. Photo therapeutic keratectomy (PTK), which uses the excimer laser to treat the surface, has the highest success rates for treating RES as proven by several studies.
How do I make an appointment?
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