The Link Between Age-Related Cataracts and Genetics
We all age, but the ways in which our bodies change, particularly, our eyesight, is influenced and could even be predicted by your genetics.
From fluctuations in weight to changes in the appearance of hair and skin, we are ever-evolving people. The same can be true for our vision.
Although many people are born with healthy eyes, others have to wear corrective lenses to achieve the ideal 20/20 vision.
If you have your sights set on trying to understand whether your vision will change as you age, we are here to tell you that it probably will- in some sense, at least.
Many people over the age of 40 require reading glasses for crisp up-close vision, but others may require more extensive eye care based on the development of age-related cataracts.
Although we can’t entirely plan for the future, taking the guesswork out of future eye health can help us understand how our vision may change over time. That’s where genetic testing comes in, helping you determine if you’re at increased risk of developing age-related cataracts, or other eye health conditions, based solely on your DNA.
Let’s explore the link between age-related cataracts and genetics.
What are age-related cataracts?
Age-related cataracts (ARC), also known as senile cataracts, are cloudy or opaque areas that form on the eye's lens.
A cataract begins when excess proteins in the eye form clumps on the lens, preventing it from sending clear images to the retina. Without clear images, the retina can not send proper signaling to your optic nerve, translating it into messaging for the brain.
They can appear in one or both eyes, generally at different times, and are most prevalent in older adults. They develop slowly over a few years and cause impaired vision.
As you age, your risk of developing cataracts increases each decade, beginning at age 40. By the age of 75, half of all white Americans have cataracts.
Cataracts are treated with specialized surgery. However, if left untreated, they can cause blindness. In fact, age-related cataract is the leading cause of blindness worldwide, accounting for approximately 80% of all cases of blindness during old age.
Symptoms
Common age-related cataract symptoms include:
- blurry vision
- trouble seeing at night
- seeing colors as faded
- increased glare and light sensitivity
- double vision
- a need for frequent changes in prescription glasses
Types
Various types of cataracts are classified based on how they develop.
They include:
- Nuclear cataracts– form in the middle of the lens and cause the center to become yellow or brown.
- Cortical cataracts– wedge-shaped and form around the edges of the nucleus.
- Posterior capsular cataracts– a faster forming type that affects the back of the lens.
- Congenital cataracts– present at birth or form during a baby’s first year. These are far less common than age-related cataracts.
- Secondary cataracts– caused by disease or medications, including glaucoma, diabetes, and the use of prednisone.
- Traumatic cataracts– develop after an injury to the eye.
- Radiation cataracts– form after a person undergoes radiation for cancer treatment.
Risk Factors
Along with old age and genetics, there are other risk factors associated with cataract development, including:
- heavy alcohol use
- smoking
- obesity
- high blood pressure
- eye injuries
- sun exposure
- diabetes
- exposure to radiation
Do genetics play a role in developing cataracts as we age?
Yes, genetics play a significant role in age-related cataract risk and development.
The development of ARC is complex, but recent studies have reported that genetic effects may explain almost 50% of the variation in the severity of cataracts with age.
Previous studies showed that specific genes involved in encoding antioxidant enzymes were associated with ARC susceptibility. 1 But more recently a wide review of existing original studies (a literature analysis of Pubmed, Web of Science,China National Knowledge Internet published before 2016) in this field was conducted to confirm or discover new genetic markers that can help explain which populations are at higher risk of developing age-related cataracts.3
The analysis showed that participants with the AA genotype4 tended to have an increased risk for ARC. This review was the first to provide a relatively thorough summary of the genes/loci involved in previous association studies of ARC.
How Do I Know If My Genes Play a Role in Age-Related Cataract Development?
DNA analysis might be the best way to determine your genetic tendency for age-related cataracts.
A DNA testing kit is simple to use. Your genetic DNA test results can reveal many answers to questions about age-related cataracts and other eye-related conditions.
Once you’ve taken an at-home DNA test, you can use your raw DNA file for further analysis of your genetic profile. Simply sign in to the Genomelink dashboard to upload your DNA file, and we will take care of the rest.
Unlock your full genetic potential today!
1 polymorphisms of genes encoding antioxidant enzymes, like glutathione S transferase (GST); genes encoding DNA repair enzymes, such as xeroderma pigmentosum complementation group D (XPD); and X-ray cross-complementing group 1 (XRCC1) have been confirmed to be associated with ARC susceptibility.
2https://pubmed.ncbi.nlm.nih.gov/28253266/
3All genetic polymorphisms reported were systematically reviewed, followed by extraction of candidate genes/loci with sufficient genotype data in 3 studies for the meta-analysis.
A total of 144 polymorphisms in 36 genes were reported in the 61 previous genetic association studies. Three polymorphisms in two genes were extracted, including rs1801131 in the methylenetetrahydrofolate reductase NADPH [MTHFR] gene, which were new for meta-analysis or the previous meta-analysis needed to be updated. They had sufficient genotype data in 3 studies.
4AA genotype of rs1801131
