Information on Cataracts
What is a Cataract?
Medically termed “Cataract” is the clouding of the crystalline lens in our eyes (Boyd, DeAngelis, & Turbert, 2019). The crystalline lens is located behind the coloured part of our eyes (iris). The crystalline lens helps to focus light onto the back part of our eyes (retina) which is responsible for transporting images to the brain for interpretation.
What are the causes of Cataract?
A clear crystalline lens in our eyes allows us to have a clear vision. The most common cause of cataract is aging, a common eye disease seen among the elderly above the age of 40 (Boyd, DeAngelis, & Turbert, 2019). The normal proteins in the crystalline lens starts to break down around age 40. This is usually the reason of what causes the lens to get cloudy. However, with factors like age, family history of cataracts, certain eye diseases, diabetes, Marfan Syndrome, under certain medications (corticosteroids), injuries to the eye, our environment or even development defects since birth can cause the lens to turn cloudy over time and eventually opaque. One of the most common causes of cataract is related to occupations or lifestyles with long hours in the sun, especially without any sunglasses to protect your eyes from harmful ultraviolet (UV) rays (Taylor, 1988).
In a population - based study by The Singapore Epidemiology of Eye Diseases, 10% of the participants aged 40 years and above were found to have visually significant cataract (best corrected visual acuity worse than 6/12 according to Wisconsin Cataract Grading System) in either eye (Chua, et al., 2017). On the other hand, people over age 60 start to have some clouding of their lenses with no significant vision problems. The rate of clouding of the lens varies between individuals.
What are the symptoms of Cataract?
Optometrist and Ophthalmologist are equipped with the knowledge and skills to detect the presence of Cataract with diagnostic equipment such as the slit lamp biomicroscopy and direct ophthalmoscope.
Early stages of Cataract may not be presented with symptoms. As the Cataract matures, the light passes through the cloudy lens in our eyes will be scattered. This results in light not being properly focused on the retina, causing blurring of vision which cannot be corrected by glasses. Other possible symptoms include phobia to light, dimming of lights / colours and / or foggy vision (Boyd, DeAngelis, & Turbert, 2019). Adopted from American Academy of Ophthalmology
What are the available treatments for Cataract?
The only treatment available now is through Cataract surgery performed by the Ophthalmologist. Usually, surgery is not necessary as long as the vision remains well, blurred vision is not affecting patients’ daily activities or increasing the risk of certain eye conditions.
Phacoemulsification surgery is a procedure to replace the natural Cataractous Cataract in our eyes with Artificial IntraOcular Lens Implant (IOL Implant) (Thompson, 2018). This process involves a small incision to the front part of our eyes to break up the Cataract into small pieces by an ultrasound probe before removal through the same incision. IOL implant will be inserted into the lens bag in our eyes through the small incision. Throughout the surgery, most of the patients will be awake with local anaesthesia to the eyes.
The Singapore National Eye Centre (SNEC) has more than 10,000 Cataract surgeries performed every year by its team of ophthalmologists. Phacoemulsification surgeries performed at SNEC has a success rate of 99.5%.
There are 2 types of IOL implant; Monofocal Lens Implant and Multifocal Lens Implant. Monofocal Lens Implant has only one focal point, usually targeted for distance vision. Thus, the patient is still required to wear reading glasses for near tasks (Thompson, 2018). Multifocal IOL Implants has more than one focal point which corrects both functional distance and near vision simultaneously with both eyes through the different ring zones of the IOL Implant. Thus, the patient is not required to wear reading glasses for near tasks (Thompson, 2018).
One way to reduce the rate of Cataract progression is to protect against sun ultraviolet by wearing sunglasses or hat when being outdoors (Boyd, DeAngelis, & Turbert, 2019).
According to the World Health Organization (WHO), it is estimated that too much exposure to ultraviolet (UV) rays from the sun causes up to 20% of the Cataracts.
It is hence critical to visit an optometrist or an ophthalmologist for a regular comprehensive eye examination to screen for cataract or other possible eye diseases, especially for the elderly so that proper and timely management can be advised.
Speak to our Optometrist and Optician to find out more how we can protect your eyes from cataracts. Let's delay onset of cataract together! #EMMEVisioncare #HarbourFrontCentreSingapore #OptometristsAndOpticians #VisionCare #OptometricServices #ComprehensiveEyeExamination #OrthokeratologyShapingSystem #FundusPhotography #OphthalmicLenses #HardContactLenses #SoftContactLenses #ProgressiveLenses
Boyd, K. (2019, October 1). What Are Cataracts? Retrieved from https://www.aao.org/eye-health/diseases/what-are-cataracts.
Chua, J., Lim, B., Fenwick, E. K., Gan, A. T. L., Tan, A. G., Lamoureux, E., … Cheng, C.-Y. (2017). Prevalence, Risk Factors, and Impact of Undiagnosed Visually Significant Cataract: The Singapore Epidemiology of Eye Diseases Study. Plos One, 12(1). doi: 10.1371/journal.pone.0170804
Clinical Outcomes at Singapore National Eye Centre. (2018, November 22). Retrieved November 6, 2019, from https://www.singhealth.com.sg/patient-care/patient-education/clinical-outcomes-snec.
Taylor, H. R., West, S. K., Rosenthal, F. S., Munoz, B., Newland, H. S., Abbey, H., & Emmett, E. A. (1988). Effect of ultraviolet radiation on cataract formation. The New England Journal of Medicine, (22), 1429.
Thompson, V. (2018). Could cataract-dissolving drops replace cataract surgery someday? Retrieved November 2, 2019, from https://www.allaboutvision.com/conditions/cataract-surgery.htm.
The known health effects of UV. (2017, October 16). Retrieved November 6, 2019, from https://www.who.int/uv/faq/uvhealtfac/en/index3.html.