In our eye, there is a crystalline lens which is encapsulated in a bag. The lens is optically clear and works together with other structures in the eye to transmit light with minimal scattering (like a magnifying glass) to project light onto the retina. This in turn sends signals to the brain for us to perceive images. In addition to helping us see, the crystalline lens also absorbs UV A and UV (harmful UV rays) to protect our retina from UV damage.
The lens grows and changes throughout our life. As we age, the components that support the health of the crystalline lens like protein, vitamins, glutathione, ascorbic acid and water degrade and this result in lesser nutrient intake. These changes, along with structural changes in the lens due to ageing and oxidative damage from UV, cause the lens to become cloudy and hence cataract formation occurs. Cataract causes vision loss and is one of the major leading causes of blindness in the world.
Factors contributing to cataract development in the elderly
A number of factors can cause cataract formation in the elderly population and it includes ageing, exposure to UV, refractive error, systemic health condition (diabetes), drug use (steroid), smoking and trauma (injury). These may cause blurry vision, glares, haloes or starbursts, changes in colour perception, dim and loss of vision. Multiple types of cataracts may form in the crystalline lens.
Ageing and exposure to UV can cause nuclear sclerotic, cortical cataracts and posterior subcapsular cataracts. Those with myopia (short-sightedness) are more prone to nuclear sclerosis cataracts whereas those with hyperopia (long-sightedness) are more prone to cortical cataract formation.
Systemic health conditions like diabetes may contribute to the formation of snowflake cataracts caused by high blood sugar levels leading to structural changes in the lens.
Posterior subcapsular cataracts can be caused by long-term use of steroids, nuclear sclerotic cataracts can be caused by smoking and lastly, traumatic (rosette) cataracts can be caused by injury or trauma.
Preserve your vision as you age
There is a myriad of ways to preserve your vision as you age:
- UV protection
- Quit smoking
- Eat a healthy diet
- Have cataract surgery when the need arises
UV protection like using sunglasses, a sun hat, umbrella may help to reduce UV exposure to the eye, slowing down cataract formation.
Smoking can generate more free radicals in the body, which increases oxidative stress and contributes to age-related cataracts. Hence, those who quit smoking can slow down cataract formation in the eye.
Natural food contains nutrients that aid in eye health like vitamin A, vitamin C, vitamin E, omega-3 fatty acids, lutein, zinc and zeaxanthin. Food with good sources of nutrients:
Vitamin A: Carrot, apricot, cantaloupe
Vitamin C: Orange, tomato, strawberry, lemon, tangerine, red bell pepper, peach
Vitamin E: Avocado, almond, sunflower seed
Omega-3 fatty acids: Salmon, tuna, sardine, halibut and trout
Lutein, zeaxanthin: Kale, spinach, romaine lettuce, broccoli, pea, egg
When a cataract is present and affects the vision, cataract surgery can be performed to regain good vision. The cataract surgeon will use an ultrasonic device to break down the cataract (phacoemulsification) and remove it via a small incision. An artificial intraocular lens (IOL) is then implanted to replace the cataract. In addition, the IOL can protect our retina from UV as it contains UV blocking. At the same time, the IOL may also correct all forms of refractive errors including astigmatism, myopia, hyperopia, and presbyopia.
Cataract treatment in Singapore
Cataract screening and treatment are readily available in Singapore.
Eye tests like visual acuity, eye pressure, slit lamp microscopy and retinal health will be done during a cataract screening for the cataract surgeon to assess the severity of the cataract. Other tests like dilated fundus examination, fundus photo, optical coherence tomography and humphrey visual field may also be performed depending on condition and symptom.
If cataract surgery is recommended, there are different types of IOL one can choose from depending on occupation, lifestyle and eye condition. Below are some common types of IOL:
- The monofocal IOL corrects the refractive error for 1 focal point only. It provides good vision for distance or near vision. Most will choose far vision and use reading glasses for near work.
- The extended depth of focus lens (EDOF) IOL corrects the refractive error for far and intermediate distances using a technology based on elongated focal points, reducing haloes and glare.
- The trifocal IOL corrects refractive error for 3 focal points. It provides good vision for near, intermediate and far distances. Haloes can be seen around point sources of light at night but it provides the greatest convenience.
Standard cataract surgery vs bladeless laser-assisted cataract surgery
There are broadly 2 types of cataract surgery:
Standard cataract surgery
A small incision is made in the cornea for the cataract surgeon to access the anterior chamber of the eye during cataract surgery. An opening is made to the capsular bag and a phacoemulsification handpiece (a small probe) is used to break down the cataract via ultrasonic waves and thereafter removed. An IOL lens implant will then be placed in the capsular bag to replace the cataract that has been removed. The incisions are self-sealing and do not require any stitches.
Bladeless laser-assisted cataract surgery
Bladeless laser-assisted cataract surgery uses femtosecond laser technology to create incisions in the cornea and capsule bag and also to break down the cataract. The broken lens is sucked out and replaced with an IOL in the capsular bag. The incisions made by the femtosecond laser are self-sealing and no stitches are required. A real-time OCT software programme is used throughout the surgery.
If you are concerned about cataracts and will like to consider a cataract screening, please contact Lang Eye Centre at +65 6684 1000 or manager@langeye.sg.
References
1. Aliancy JF, Jan 2018 – Crystalline Lens and Cataract https://europepmc.org/article/nbk/nbk476171
2. Nicola Pescosolido, 2016, Int J Ophthalmol 2016 9(10): 1506-1517 – Age- related changes in the kinetics of human lenses: prevention of the cataract https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5075670/
3. J C Javitt, F Wang, S K West, 1996 Annu Rev Public Health 1996:17:159-77 – Blindness due to cataract: epidemiology and prevention https://pubmed.ncbi.nlm.nih.gov/8724222/
4. Jessica Mathew, 2019 – Exposure of the Eye to Ultraviolet light “https://us.alconscience.com/sites/g/files/rbvwei1736/files/pdf/Exposure-of-the-Eye-to-Ultraviolet-Light-US-PR1-1900053.pdf”
5. Juan Ye, June 2012 – Smoking and risk of age-related cataract: A meta – analysis https://iovs.arvojournals.org/article.aspx?articleid=2128544
6. Celia Vimont, Apr 07 2023 – 36 Fabulous Foods to Boost Eye Health https://www.aao.org/eye-health/tips-prevention/fabulous-foods-your-eyes
7. Geetha David, Jan-Feb 2016 – The Evolution of Cataract Surgery https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6139750/
