what is keratoconus melbourne

What is Keratoconus? Symptoms, Causes, and Treatment

Keratoconus is an eye disease characterised by progressive thinning of the cornea and a resultant bulging of the weakened tissue. The cornea is the transparent dome at the front of the eye, largely responsible for bending (refracting) light through its surface to provide clear vision. Normally, the cornea is uniformly round, like half a soccer ball. As the cornea thins and bulges outward during keratoconus, it may take on more of a cone shape, which is where the name “keratoconus” is derived from. The distortion of this tissue during keratoconus results in impaired vision. 

Keratoconus is found at a prevalence of about 1 in 2000. Usually, the condition is present in both eyes but it is not uncommon for it to be more advanced in one eye compared to the other. This can lead to differences in the potential to improve vision between the eyes by conventional means, and one eye may require corneal surgery while the other can still be corrected with optical aids like a contact lens.  

Most cases of keratoconus are first detected between the ages of 10 and 25 years old but there are some patients who may go undiagnosed for longer. 

Symptoms of keratoconus can often be dismissed for something else but a thorough eye exam by an optometrist or ophthalmologist can help to diagnose the condition. Typical symptoms include:

  • Blurred or distorted vision: this is a result of the distorted cornea.
  • Glare sensitivity: as light passing through the cornea is distorted, light sources such as oncoming car headlights or traffic lights may appear flared or in a starburst pattern, making them uncomfortable to view.
  • Ghosting or double vision: the irregularity of the cornea can result in the appearance of a second image of the one object. 
  • Frequent changes to your contact lens or glasses prescription: this will typically involve increasing degrees of astigmatism. 

explained what is keratoconus melbourne

Though keratoconus is not typically associated with pain, advanced keratoconus cases may involve a sudden influx of fluid into the cornea, known as hydrops. This situation can be painful and cause an abrupt drop in vision. 

While these symptoms may be nonspecific to keratoconus, an eye care professional can perform tests to identify keratoconus as the underlying condition. These tests include:

  • Pachymetry: a measurement of the thickness of the cornea will determine if it is thinner than average. Multiple measurements over time will detect progressive thinning. 
  • Corneal topography or keratometry: similar to geographical topography, a corneal topographer maps the surface curvature of the cornea, noting any uneven areas. Keratometry is similar but much more simplified and only measures a small area. 
  • Refraction: multiple measurements of your prescription over time can monitor increasing levels of astigmatism as well as keep track of your best corrected visual acuity.  

 

What is Keratoconus Caused By? 

The question what is keratoconus caused by is not currently fully understood. Experts believe there to be a combination of both genetic and environmental factors. Studies suggest that around 20% of people with keratoconus also have at least one relative with the condition. There are also known genetic diseases that are often associated with keratoconus, such as Down’s syndrome, Ehlers-Danlos syndrome, retinitis pigmentosa, and Marfan’s syndrome. It is also possible that there is some genetic predisposition for corneal weakness, as some studies indicate keratoconic corneas lack stable structural fibres or have an impaired ability at repairing oxidative damage to their cells. 

A history of allergic disease, known as atopy, is a known risk factor for the development of keratoconus. Atopy encompasses conditions such as asthma, eczema, and hayfever. Related to this is another known risk factor for keratoconus – eye rubbing. It is thought that vigorous eye rubbing triggers the corneal fibres to break down further and has been implicated as contributing to keratoconus in those with a genetic predisposition. 

 

Treatment

In the early stages of keratoconus it is possible to improve vision with normal glasses or soft contact lenses. However, as the disease progresses, the potential to improve vision with these options becomes less likely and you may need to be fitted with hard contact lenses, known as rigid gas permeable (RGP) lenses. Some cases are suitable for a procedure known as corneal cross-linking, which utilises UV light to strengthen the corneal fibres. In advanced disease, even RGP lenses may be insufficient at improving your vision and your ophthalmologist may recommend corneal surgery. A corneal graft can be performed by an eye specialist experienced in corneal surgery, and may be the only option for successfully restoring sight to a functional level. 

If you need further information on what is keratoconus or suspect that you or a family member may have the condition, speak to your eyecare professional. 

 

 

Note: Any surgical or invasive procedure carries risks. Before proceeding, you should seek a second opinion from an appropriately qualified health practitioner.

symptoms of dry eye melbourne

Symptoms of Dry Eye – Understanding Dry Eye Disease

Many people will encounter at least one of the symptoms of dry eye in their lifetime. For some, dry eye may be a mild, transient irritation, while for others it can be a significant, debilitating condition that interferes with daily tasks and can only be controlled with targeted dry eye treatment

The condition of dry eyes has now been recognised as a real disease with real impact, sometimes called dry eye disease or dry eye syndrome. The global prevalence of dry eye disease varies, with some studies reporting up to 50% of the population suffers from some degree of the condition. As the symptoms of dry eye disease and its effects vary across such a wide range, dry eye is thought to be significantly under-diagnosed. Many people with only a mild case of dryness may opt to self-manage rather than seek the care of an eye care professional for dry eye treatment

 

What is Dry Eye Disease?

Dry eye syndrome, or dry eye disease, is a little more complex than simply being eyes that feel dry. A healthy eye’s surface is covered by a stable layer of tears, known as the tear film. This tear film is composed of many different components, such as proteins, lipids, and antibodies, that work together to keep the surface of the eye well lubricated, protected, and nourished. The main bulk of the tear film is produced by three types of glands around the eye:

  • The lacrimal gland is located above the upper eyelid, producing the watery, or aqueous, component of the tear film
  • Goblet cells of the conjunctiva secrete a mucous layer which helps the tear film to adhere to the eye
  • The meibomian glands line the upper and lower eyelids, secreting an oil which sits at the outer surface of the whole tear film, reducing evaporation of the aqueous component

treatment symptoms of dry eye melbourneThere are a multitude of factors that can contribute to dry eye disease. Experts have divided the condition into two broad classifications – evaporative dry eye and aqueous deficiency dry eye. Evaporative dry eye occurs when the tear film is unstable and evaporates too quickly from the surface of the eye.

The majority of evaporative dry eye conditions are a result of a dysfunction of the meibomian glands mentioned earlier but can also be caused by blepharitis (accumulation of irritants around the eyelashes and subsequent inflammation of the eyelids), eye allergies, preservatives in eye drop medications, or contact lens wear. Most cases of dry eye disease are evaporative in nature.  Aqueous deficiency dry eye comprises a much smaller percentage of dry eye disease but includes underlying causes such as autoimmune disease, systemic medications, laser eye surgery, or dysfunction of the lacrimal gland. Identifying the type of dry eye and the contributing factors is important for effective dry eye treatment

 

What Are the Symptoms of Dry Eye? 

The symptoms of dry eye are not always obvious, and some may be mistaken for other conditions, resulting in inappropriate treatments which are ineffective. 

Symptoms of dry eye can include:

  • The sensation of dryness: not everyone with dry eye will identify the eyes as actually feeling dry, though this is the most obvious symptom. The feeling of dryness can range in severity from person to person. 
  • Grittiness, stinging, or burning: these are also common sensations associated with dry eye. Some people may describe the feeling of having a foreign object, like an eyelash or speck of dust, stuck in the eye that can’t be washed out. The irritation felt by a dry eye is due to the underlying inflammation associated with dry eye disease, as well as the surface of the eye becoming exposed to the environment as the protective tear layer evaporates.
  • Red eyes: while this is a common symptom of dry eye disease, the presence of a red or pink tinge to the whites of the eye or the rims of the eyelids can cause some people to seek inappropriate treatments, such as antihistamines or antibiotics, when there is no allergy or infection involved. Although the added moisture from these eye drops may help alleviate some of the redness, they are not an effective dry eye treatment
  • Blurry vision: because the tear film is the first refractive surface that light passes through in order to reach the back of the eye for vision, if this tear layer is uneven or unstable, it can cause vision to appear blurry. People with dry eye may find their vision is quite variable, especially between blinks. 
  • Glare sensitivity: light scattered by an uneven tear film may cause the eyes to feel more uncomfortable and sensitive to light sources, whether it be the sun outdoors or the light from a screen. 
  • Watery eyes: counterintuitively, watery eyes may in fact be a symptom of dryness. As the eye’s surface feels dehydrated, biological feedback mechanisms trigger a reflex to produce more tears, which can end up with the eye feeling watery instead. 

Dry eye disease is a very common condition. In most cases it can be managed with simple remedies such as lubricant eye drops or home therapies such as warm compresses. In some cases, a comprehensive eye examination with an eyecare professional may be necessary to formulate a more intensive, targeted treatment plan.