Exposure to heavy metal in soil, water, or the environment is a high-risk factor for developing glaucoma, researchers from China have claimed in a study, adding that there is an association between endocrine disruptors and age-related eye diseases.
Glaucoma is described as a group of eye diseases that can cause vision loss and blindness by damaging the optic nerve.
The study was conducted by researchers at the Department of Ophthalmology of ‘The Second Affiliated Hospital’ in the Hefei-based Anhui Medical University. It was published on February 10 in the journal Nature.
“Using follow-up data from the National Health and Nutrition Examination Survey (NHANES) database, we have collected information on 2,572 subjects and used generalised linear model to investigate the association between urinary heavy-metal levels and glaucoma risk…” the researchers write, adding that their results “provided important insights into the potential role of heavy metals in the pathogenesis of glaucoma, facilitated the discovery of new biomarkers for early diagnosis, risk assessment, and timely treatment of glaucoma, and guided public health measures to reduce heavy-metal exposure”.
ABPLive approached Indian doctors to ask some questions arising from the study: For example, how can contact with or exposure to heavy metals cause glaucoma, and what preventive measures can be taken by those involved in industries requiring heavy-metal exposure?
A senior ophthalmologist from a well-known eye hospital in Chennai refused to comment on the study, saying, “… This heavy metal and glaucoma is very new and not really proven, just this study claims and [there is] no real evidence.”
Dr Amrita Kapoor Chaturvedi, a glaucoma specialist at Amrita Hospital, Faridabad, did weigh in on the questions, but said “she doesn’t agree with the findings of this particular China-based study”. Excerpts from the exchange (links mentioned in brackets are sources cited by Dr Kapoor):
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ABP: Cumulatively, what are the common causes of glaucoma?
Dr Amrita Kapoor: Glaucoma is primarily characterised by damage to the optic nerve, often associated with elevated intraocular pressure (IOP). The common causes and risk factors include:
- Elevated Intraocular Pressure: Increased pressure within the eye can damage the optic nerve
- Age: Individuals over 60 are at higher risk
- Family History: A genetic predisposition can increase susceptibility
- Ethnicity: African-Americans, Latinos, and Asian-Americans have a higher prevalence of certain types of glaucoma
- Medical Conditions: Diabetes, hypertension, and heart disease are linked to a higher risk
- Prolonged Corticosteroid Use: Long-term use of steroids can lead to increased IOP
- Eye Injuries: Trauma can damage the eye’s drainage system, leading to glaucoma.
While elevated IOP is a significant risk factor, glaucoma can occur even with normal eye pressure, known as normal-tension glaucoma. (Source: mayoclinic.org)
ABP: How can the presence of heavy metals in the environment affect a person’s eyesight?
Dr Amrita Kapoor: Exposure to heavy metals such as lead, mercury, and cadmium has been implicated in various ocular pathologies. These metals can accumulate in ocular tissues, including the retina and optic nerve, potentially contributing to neurodegenerative processes. For instance, studies have found that toxic metals are taken up by the human retina and optic nerve head, supporting the hypothesis that such accumulations could contribute to the pathogenesis of age-related macular degeneration. (Source: journals.plos.org)
Additionally, chronic exposure to heavy metals has been associated with symptoms like burning sensation, tearing, and periodic redness in the eyes. (Source: pubmed.ncbi.nlm.nih.gov)
ABP: What are the symptoms one should watch out for if one suspects glaucoma development in the eyes?
Dr Amrita Kapoor: Glaucoma is often asymptomatic in its early stages. As the disease progresses, symptoms may include:
- Peripheral Vision Loss: Gradual loss of side vision, often unnoticed until significant damage has occurred
- Tunnel Vision: In advanced stages, vision may narrow, resembling tunnel vision
- Eye Pain: Particularly in acute angle-closure glaucoma, severe eye pain can occur
- Redness in the Eye: Especially during acute attacks
- Halos Around Lights: Seeing rainbow-coloured circles around lights
- Nausea and Vomiting, and accompanying severe eye pain
Regular comprehensive eye examinations are crucial for early detection, as significant optic nerve damage can occur before noticeable symptoms arise. (Source: mayoclinic.org)
ABP: What steps must one take to sanitise the environment of heavy metals; rather, how to eliminate or scale down the risk of developing glaucoma due to heavy-metal exposure?
Dr Amrita Kapoor: To mitigate the risk of heavy-metal exposure affecting ocular health:
- Identify And Eliminate Sources: Determine potential sources of heavy metals in your environment, such as certain industrial activities, contaminated water, or specific consumer products, and take steps to remove or reduce exposure
- Use Water Filters: Install appropriate water filtration systems to reduce heavy-metal content in drinking water
- Ensure Proper Ventilation: In workplaces or homes where heavy metals might be present, ensure adequate ventilation to reduce inhalation risks
- Regular Health Screenings: Undergo routine medical check-ups to monitor heavy-metal levels in your body
- Personal Protective Equipment (PPE): Use appropriate PPE if you work in environments with potential heavy-metal exposure
- Advocate for Environmental Regulations: Support and adhere to regulations aimed at reducing environmental heavy-metal contamination.
While direct causation between heavy-metal exposure and glaucoma is still under investigation, minimising exposure is prudent for overall health.
ABP: How often do you see patients with glaucoma blamed on heavy-metal exposure? How common or rare is this type of glaucoma?
Dr Amrita Kapoor: In clinical practice, attributing glaucoma directly to heavy-metal exposure is relatively uncommon. While studies suggest a potential link between heavy-metal accumulation and ocular diseases, definitive evidence connecting heavy-metal exposure as a primary cause of glaucoma is limited. Most cases of glaucoma are associated with the more established risk factors previously mentioned. However, in patients with known significant heavy-metal exposure, it is advisable to monitor ocular health closely.
In summary, while heavy-metal exposure has been implicated in various ocular conditions, its direct role in causing glaucoma remains an area of ongoing research. Regular eye examinations and minimising exposure to environmental toxins are essential steps in preserving ocular health.
The writer is a senior independent journalist.
[Disclaimer: The information provided in the article, including treatment suggestions shared by doctors, is intended for general informational purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified healthcare provider with any questions you may have regarding a medical condition.]
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