Published: 1 September 2020 · Last updated: 16 September 2026 · Publisher: Smart Vision Optometry
At a glance
Myopia and cataracts are different conditions, but population studies show an association between myopia and some forms of cataract. A cataract can also change the eye’s focusing power and make a prescription more short-sighted. This does not mean that one condition always causes the other. People with high myopia benefit from regular eye-health checks and individual planning if cataract surgery is considered.
What are myopia and cataracts?
Myopia, or short-sightedness, is a refractive condition in which distant objects look blurred because light focuses in front of the retina. It commonly occurs when the eye is longer than expected for its focusing power.
A cataract is clouding of the eye’s normally clear lens. Cataracts usually develop gradually and may cause blurred vision, glare, haloes, reduced contrast or difficulty driving at night. They are common with ageing, although younger people and children can also develop them. Healthdirect Australia’s cataract guidance explains symptoms, risk factors and treatment.
What does the evidence show?
The relationship is an association rather than a simple cause-and-effect rule. The population-based Blue Mountains Eye Study found evidence linking myopia with incident cataract and cataract surgery after adjustment for several other factors. A later longitudinal analysis from the same study found that myopia was associated with a higher incidence of nuclear and posterior subcapsular cataract. The size of an individual patient’s risk cannot be inferred from these studies alone.
High myopia is also associated with other retinal and macular risks. Our related article explains the distinction between cataract and myopic macular degeneration; the two conditions affect different structures and require different assessment and management.
Why can a cataract change a glasses prescription?
Changes in the lens, particularly with a nuclear cataract, can alter refraction and create a shift towards myopia. Some people temporarily notice better unaided near vision, sometimes called “second sight”, while their distance vision or overall clarity worsens. This is not a recovery of eye health and may be a reason to have the change assessed rather than simply replacing reading glasses.
How are cataracts assessed and treated?
An eye examination can assess visual acuity, refraction and the lens, and may include retinal imaging or other tests where clinically appropriate. Smart Vision Optometry’s advanced eye-health testing page explains the available assessment tools.
Updated glasses can sometimes help during early cataract development. When cataracts interfere with everyday activities, referral to an ophthalmologist may be appropriate. Cataract surgery removes the cloudy lens and replaces it with an artificial intraocular lens; experimental compounds should not be presented as established alternatives to surgery.
What does high myopia mean for cataract-surgery planning?
High myopia does not mean that cataract surgery cannot be performed. It does mean that axial length, retinal health, previous retinal treatment and the choice of lens power may need particular attention. A large US registry study found retinal detachment after approximately 1 in 500 cataract procedures in people over 40 within one year, with high myopia among the additional risk factors. An ophthalmologist can explain an individual’s risks and expected refractive outcome.
New flashes, a sudden increase in floaters, a shadow or a curtain across vision require urgent assessment because they can be symptoms of retinal detachment. Do not wait for a routine appointment if these symptoms occur.
Monitoring myopia and eye health
For a child or young person whose myopia is progressing, an assessment can consider prescription history, eye growth, eye health and suitability for evidence-informed management. Learn about myopia control at Smart Vision Optometry and the dedicated information available from Myopia Prevention Australia.
Book an eye-health assessment, or contact the Bondi practice on (02) 9365 5047 or the Mosman practice on (02) 9969 1600.
Frequently asked questions
Does myopia cause cataracts?
Population studies show an association between myopia and some cataract types, but that does not prove that myopia directly causes every cataract. Age, ultraviolet exposure, smoking, diabetes, medicines, eye injury and other factors may also affect cataract risk.
Can a cataract make my prescription more short-sighted?
Yes. Changes in the lens, especially with a nuclear cataract, can shift refraction towards myopia. A sudden or repeated prescription change should be assessed because clearer near vision does not necessarily mean the eye is healthier.
Does high myopia change cataract-surgery planning?
It can. The surgeon may give particular attention to axial length, retinal health, previous retinal treatment, intraocular-lens calculations and the person’s desired focusing outcome. Risks and benefits should be discussed for the individual eye.
