brisbane optometrist cataract screening and eye testingWHAT IS A CATARACT? A cataract is a clouding of the natural crystalline lens of the eye. The crystalline lens sits behind the iris and pupil, and is responsible for the dynamic range of focus we have. Our eyes can accurately focus from distance to near as a direct result of the lens changing shape, similar to a camera. A naturally clear lens passes focussed light through to the retina which gives us clear vision. If the lens becomes cloudy, then less light passes through to the retina, and our vision becomes blurred or foggy as shown in the second image.
HOW ARE CATARACTS DETECTED? A cataract is most often discovered due to reduced vision on a distance letter chart. This typically would happen during examination by an optometrist or general practitioner. Once the presence of reduced vision has been established, then further examination of the eye with a slitlamp microcope will confirm whether cataracts are present and the cause of the reduced vision. As cataracts generally have a greater effect on vision in dim light, a low contrast chart can be used to help grade the severity of vision loss due to the cataract. It is important to realise that cataracts can be present with other eye conditions such as glaucoma and macular degneration, so it is still important to be screened for these common eye conditions.

WHAT ARE THE RISK FACTORS FOR CATARACT? Cataracts most commonly occur with increasing age, due to the gradual clouding of the otherwise clear crystalline lens. This natural process begins after the age of 40 and continues throughout life. Some factors that may cause cataracts or increase cataract development include excessive UV exposure, injury, family history, diabetes, smoking and corticosteroid medication. Cataracts are readily detected by routine eye examination, and typically can be visualised using a slitlamp microscope.

ARE THERE DIFFERENT TYPES of CATARACT? Different types of cataracts exist, with the most common causing a general clouding of the central portion of the lens, whilst other forms cause clouding on the front or back surface of the lens. Each type can have a slightly different effect on vision, however generally each will cause blurred vision and glare sensitivity in various degrees.

slitlamp-brisbane-optometristHOW DO I KNOW IF I HAVE CATARACTS? Common symptoms of cataracts include, blurry or foggy vision, difficulty with driving particularly in low light, needing more light to read or sew, changes in spectacle prescription, increased glare sensitivity, seeing colours as being more faded. Cataracts often progress slowly however sometimes cataracts develop very quickly, so we recommend having an eye examination at least once a year when early cataracts have been diagnosed. 

WHAT IS THE TREATMENT OF CATARACT? Cataracts are readily resolved by cataract surgery. Cataract surgery involves removing the cloudy natural lens of the eye, and replacing it with a new clear artificial lens. This proceedure is performed as day surgery and is relatively quick, painless, with a short recovery time. After surgery medicated eye drops will typically be used for the first month and vision improves over the first week and usually stabilises by one month after surgery. At this point, it is usually safe to have your prescription checked and new glasses made to suit your new vision.

DO I NEED GLASSES AFTER CATARACT SURGERY? This is probably one of the most asked questions once someone realises they would benefit from cataract surgery. Normally prior to cataract surgery consideration is given to the visual outcomes following surgery. This is often determined by what you have previously worn in the form of glasses and contact lenses. Four common options are typically discussed.

  • Distance vision is provided for both eyes, with glasses being required after surgery for reading and middle vision.
  • Mini-monovision whereby distance vision is aimed for in the dominant eye, and a small amount of reading/middle vision is provided in the non-dominant eye. This option provides less dependance on glasses in everyday tasks, however glasses are still often required for long distance or night driving, and for extended periods of reading particularly with small print.
  • Full monovision provides distance vision in the dominant eye and near vision in the non-dominant eye. Although the brain can usually adapt to this option over a period of months, it is prudent to simulate this option with a contact lens for a week to see how you cope. We can provide this service to you even if you haven't worn contact lenses previously. Once more, this option provides less dependance on glasses in everyday tasks, however glasses are still often required for long distance or night driving, and for extended periods of reading.
  • Multifocal intraocular lenses are available which offer distance and near vision for each eye. Glasses may still be required in low light, and halos and glare can be significant for some people.