Cataract

The lens is mainly composed of protein and water. A cataract is caused by the coalescence of natural proteins in the lens. Normally, these proteins are organized in such a way that the lens remains clear, and light is not blocked from entering the eye. However, as we age, the protein components of the lens tend to fuse together forming a cloudy area.

The lens is responsible for focusing light on the retina, the light-receptive tissue that lines the back of the eye. In a normal healthy eye with a clear lens, light passes unobstructed through the lens to the retina. The retina then converts the light into neural signals that are sent to the brain. In order for the brain to receive a sharp image, the lens must be clear. 

Consequently, people with cataracts often experience blurry vision over time as their lens gets cloudier. Additionally, cataracts due to age can cause discolouration of the lens from clear to a yellowish or brownish hue. This change in colour may result in a change in colour perception. Other symptoms of cataracts include glare, difficulty with night vision, poor vision in low lighting conditions, and double vision occurring in one eye.

A cataract can be detected during a routine comprehensive eye examination. Routine eye exams are also helpful in monitoring cataract progression. 

• Cataracts are identified by measuring changes in your vision and in your prescription, by assessing your eyes with a slit lamp biomicroscope, ophthalmoscopy, and photography. It is very helpful to have annual exams with the same eye doctor or clinic so that your records can be reviewed for changes over time.

Although cataracts are irreversible, there are methods of managing the symptoms: 

• In the early stages, your optometrist will ensure that you are retaining the level of vision required for driving, and that you are comfortably able to do your daily tasks and hobbies. 
• Often, slowly progressing cataracts will create a change in the lens shape such that your eyeglass prescription needs to change. Keeping your prescription current and selecting appropriate anti-reflective coatings can help reduce glare. Wearing prescription sunglasses and other UV protection will also reduce cataract formation over time. 
• With the dulling of vision caused by cataract changes, using brighter lighting for reading, and even magnifying lenses for small detail, may be necessary. 

Your doctor will carefully review changes in your vision performance, and if these options are ineffective, cataract surgery may be advised to remove the cloudy lens and replace it with an artificial intraocular lens (IOL).

Most cataracts are due to aging and known as nuclear sclerotic cataracts. However, there are other types of cataracts: traumatic cataracts are cataracts that have developed due to injury; congenital cataracts are present at birth and may or may not affect vision; a radiation cataract is caused by exposure to certain types of radiation. 

Cataracts develop at different rates and affect vision more or less dramatically based on what part of the lens they are located in, or how dense they are. Cortical cataracts present like crystal-like spokes starting from the outer part of the lens and grow inwards. Posterior subcapsular cataracts start at the back outer layers of the lens, and often are more centrally located.

Certain lifestyle changes may help prevent cataract formation, such as maintaining a healthy antioxidant-rich diet, protecting the eyes from ultraviolet radiation by wearing sunglasses and hats, and refraining from smoking.

Numerous medications and medical conditions can increase the development of cataracts. Your optometrist will review your medical history and medications to ensure we are aware of any risk factors. Annual eye exams are recommended to best monitor the development of cataracts, and the effect they may be having on your vision.