What is myopia?Myopia, also known as 'short-sightedness' or 'near-sightedness', causes people to have difficulty seeing distant objects clearly. It's estimated that there are currently 2 billion myopic people in the world,1 a figure that is growing rapidly.
Axial myopia is caused by the eyeball being too long. This means that instead of focusing on the back of the eye (the retina), light focuses in front of it, causing blurred vision.
- Myopia usually begins in childhood at school age (six years and onwards) and can worsen until early adult years. This is referred to as youth-onset or juvenile-onset myopia. It can also occur in adults (ages 20 to 40) with no prior history of problems in childhood, termed early adult-onset myopia. One can also be born with high levels of myopia (congenital myopia)
- Myopia can be corrected by spectacles, contact lenses and refractive surgery.
- Myopia affects about 1 in 4 people in Australia, 1 in 3 in America and 1 in 2 in some Asian countries. In 2010, it affected more than a quarter of the world’s population.1
- Growing levels of high myopia are increasing the risks of serious eye conditions, such as myopic macular degeneration, cataract, glaucoma and retinal detachment, many of which may lead to permanent blindness.
- The incidence of myopia has been rapidly increasing across the world. By 2020, it is estimated that the number of people with myopia will grow to one third of the world’s population (2.6 billion) and by 2050 there will be 4.8 billion myopes (around half the world's population).1
- The causes of myopia are both genetic and environmental. It is suggested that increased urbanisation and close-range activities e.g. reading and computer work, are increasing the incidence of myopia.
- It is predicted that by 2050 there will be almost 1 billion high myopes globally.1
What is presbyopia?
Presbyopia literally means ‘old sight’. When we read or look at something close, the flexible lens inside the eye changes shape to provide the close focus required. However, as we age, the lens becomes less flexible and its ability to change shape is reduced.
This inevitable loss of flexibility is called presbyopia and causes near vision to be blurred.
- Presbyopia is a natural part of ageing and a gradual process that usually begins at around 40 years of age. As a result, almost everyone over the age of 45 needs vision correction for reading and other close work.
- Presbyopia is the most widespread ocular problem in the world. There are currently over 1 billion people with presbyopia.2
- In 2010, approximately 44% of the Australian population were in the presbyopic age bracket (almost 10 million people).2
- Presbyopia can be corrected with reading spectacles, bifocal or multifocal spectacles, and contact lenses.
our presbyopia contact lenses click here
What is 'dry eye'?
'Dry eye' is one of the most common ocular complaints but it's not as simple as it sounds. It is a disorder of the tears and ocular surface that results in eye discomfort, visual disturbance, and often ocular surface damage. Producing insufficient tears is only one of several possible causes.
- Five to 30 percent of adults aged 50 years or older have some degree of dry eyes.3 It is more common in women than men and the prevalence is higher in Hispanic and Asian populations.3
- Possible symptoms of dry eye syndrome include sore, watery, red eyes and scratchy, burning/stinging sensations on the eye.
- Common risk factors of dry eyes have been identified. Examples of these include: old age, female gender; post-menopausal oestrogen therapy; a diet low in omega 3 essential fatty acids; refractive surgery; vitamin A deficiency; radiation therapy; some systemic conditions and certain classes of medications.
Causes of dry eye can be complex and vary between individuals, but a simple way of classifying its aetiology would be:
- Decreased tear production
- Excessive tear evaporation
- An abnormality in the production of mucus or lipids normally found in the tear layer
- Diagnosis often depends on a thorough history taking and clinical tests
- Management of dry eye depends on the causes and severity of the condition. Besides the conventional artificial tears and lubricants, other treatment options include topical agents such as cyclosporine, antibiotics and anti-inflammatories such as tetracycline, serum tear substitutes, punctual plugs, dietary supplementation such as essential fatty acids and environmental strategies.
Contact Lens Related ‘Dry Eye’
The presence of a contact lens on the eye creates several changes on the ocular environment, especially to the tear film and blink pattern. The changes are affected by the characteristics of the contact lens and some patients may experience dry eye symptoms.
Ocular dryness related to contact lens wear is different from symptoms related to dry eye disease and could be one of the major issues relating to contact lens discomfort and discontinuation. This is a key area of concern with contact lens wear that the Brien Holden Vision Institute is currently tackling through the 'Ocular Comfort' program.
Meibomian gland dysfunction and dry eyes
‘Dry eye’ is one of the most common complaints by a patient consulting an eye care practitioner. The discomfort caused by dry eyes affects millions of people worldwide.
- The meibomian glands are found in the upper and lower eye lids and secrete an oily substance called meibum. This substance forms the upper lipid layer of the tear film which functions to protect the water-based tears underneath from evaporating. Hence, the presence of a good quality lipid layer is vital to the integrity and stability of the tear film, and subsequently ocular comfort.
- Dysfunction of the meibomian gland occurs when the gland becomes blocked and/or the quantity or quality of the secretion alters.
- Ocular discomfort such as itchiness, dryness and irritation often result.
- Meibomian gland dysfunction is reported to affect 70% of people, with greater prevalence in Asian populations. It is believed to be associated with a form of dry eyes.
Research we are conducting in the area of dry eye includes:
Other Eye Conditions
In addition to common refractive errors, eye conditions that may impact on your vision and eye health include cataract, conjunctivitis, diabetic retinopathy, glaucoma and macular degeneration. Below are brief definitions of some of the more common eye conditions.
Cataract formation can change the power of the eye, alter the perception of colour and ultimately, if left untreated, cause blindness. Usually, both eyes are affected but not necessarily at the same rate. Cataract can be present in a new-born.
Glaucoma is normally associated with raised fluid pressure (high tension) inside the eye. The term 'normal tension' (or 'low tension') glaucoma is used for those cases with optic nerve damage and visual field loss, but normal or low intraocular pressure (IOP). IOP is the only modifiable risk factor for glaucoma. However, some people may have high IOP for many years and never develop nerve damage, while others can develop significant damage at a relatively low pressure.
Glaucoma can be roughly divided into two main categories, "open-angle" and "closed-angle" glaucoma. Closed-angle glaucoma can appear suddenly and is painful; visual loss can progress quickly, but the discomfort often leads patients to seek medical attention before permanent damage occurs. Open-angle (or chronic glaucoma) tends to progress at a slower rate and patients may not notice they have lost vision until the disease has progressed significantly.
- Holden BA, Fricke TR, Wilson DA, Jong M, Naidoo KS, Sankaridurg P, Wong TY, Naduvilath TJ, Resnikoff S, Global Prevalence of Myopia and High Myopia and Temporal Trends from 2000 through 2050, Ophthalmology, May 2016 Volume 123, Issue 5, Pages 1036–1042.
- Holden BA, Fricke TR, May Ho S, Wong R, Schlenther G, Cronjé S, Burnett A, Papas E, Naidoo KS, Frick KD, ‘Global vision impairment due to uncorrected presbyopia’, Archives of Ophthalmology, Vol 126 (No. 12), Dec 2009.
- International Dry Eye WorkShop Subcommittee, 2007, ‘The epidemiology of dry eye disease: Report of the epidemiology subcommittee of the International Dry Eye WorkShop (2007), The Ocular Surface, April 2007, Vol 5 (2).