Topics

Public Health Vision Concerns

UV Damage to the Eyes

UV rays, or ultraviolet radiation, can be very damaging to structures of the eye. It is therefore important to protect the eyes when there is exposure to UV rays. UV radiation is electromagnetic radiation between 100-400 nanometers and is not visible to humans.³  UV radiation can be further broken down into UVA, UVB and UVC based on the wavelengths of the rays.^2,4  Ocular damage occurs mainly from UVA and UVB.³  Exposure to UV radiation comes mainly from sunlight, but artificial exposures can come from tanning beds, some indoor lights and some types of lasers.^1,4

Damage can occur at different layers/structures of the eye. Photokeratitis is damage to the cornea (front/clear part of the eye) from intense UVB exposure.  This can occur when welding without proper protection and is known and “welder’s flash.” ³  Other conditions that can form on the anterior portion of the eye from chronic UV exposures are pinguecula and pterygia.³  These are growths that form on the conjunctiva and cornea, respectively. Certain cataracts (clouding of the lens inside the eye) can be caused by exposure to UV radiation.³

Solar UV radiation is the most intense during the summer months and during the midday hours.²  Exposure risks are also elevated when jobs/activities take place on snow, water or sand due to the reflectivity of the rays off these surfaces.²

Because of the ocular conditions that can be associated with UV radiation exposure, it is extremely important to protect the ocular structures when UV exposure is occurring.  It is recommended to wear sunglasses that block 99-100% of UVA and UVB when outdoors.¹  It is also important to wear proper eye protection when exposed to any other source of UV radiation such as lasers, tanning beds and welding machines.

Sources:

1. Ultraviolet (UV) Protection. American Optometric Association website. https://www.aoa.org/healthy-eyes/caring-for-your-eyes/uv-protection?ss=y.
2. Ultraviolet (UV) Radiation. Food and Drug Administration website. https://www.fda.gov/radiation-emitting-products/tanning/ultraviolet-uv-radiation. Last updated August 19, 2020.
3. Ultraviolet Radiation Safety. Case Western Reserve University website. https://case.edu/ehs/sites/case.edu.ehs/files/2018-02/uvsafety.pdf.
4. Ultraviolet Radiation.Centers for Disease Control and Prevention website. https://www.cdc.gov/nceh/radiation/ultraviolet.htm. Last Reviewed August 25, 2016.

Myopia Progression

Myopia, or near-sightedness, is a very common cause of blurry distance vision. Over a quarter of the world’s population has myopia and around 4% of the world’s population has high myopia (defined as > 5.00 D of myopia).^1,4  The World Health Organization estimates that half of the world’s population will be myopic by 2050. Myopia, and especially high myopia, can cause permanent visual impairments due to the development of ocular pathologies such as glaucoma, cataracts, retinal detachments and choroidal neovascularization.^1,2  This presents a public health concern.

The progression of myopia is caused by lengthening of the eye.¹  Current thinking is that unfocused light/images (hyperopic defocus) stimulates a chemical reaction that leads to elongation of the eye .¹  Myopia can also be attributed to activities that involve near visual stimuli, and is related to the length of time and magnitude of the near visual tasks.  Evidence exists that spending more time outdoors during childhood can lower myopia development risk and decrease the progression of myopia.^1,2

A cross-sectional study recently published in JAMA Ophthalmology found that the prevalence of myopia increased 1.4-3 times in 2020 for children age 6-8 years after home confinement in China due to COVID-19.³  The study included data from 6 consecutive years (2015-2020).  During the home confinement period, the children’s indoor activities and screen time were increased and their outdoor activities decreased.

Some current treatments to combat the hyperopic defocus and the chemical cascade that leads to elongation of the eye include spectacles to induce peripheral myopic defocus, contact lenses inducing peripheral defocus, increasing time spend outdoors and low-dose atropine eye drops.^1,4

Sources:

1. Wasserman B, Franz T, Rana N.A Review of Advances in Myopia Management. Review of Ophthalmology website. https://www.reviewofophthalmology.com/article/a-review-of-advances-in-myopia-management. Published August 10, 2020.
2. Lingham G, Mackey D, Lucas R, et al.How Does Spending Time Outdoors Protect Against Myopia? A Review. British Journal of Ophthalmology 2020;104:593-599.
3. Wang J, Li Y, Musch D, et al. Progression of Myopia in School-Aged Children After COVID-19 Home Confinement. JAMA Ophthalmol. 2021;139(3):293-300.doi:10.1001/jamaopthalmol.2020.6239.
4. Holden B, Mariotti S, Kocur I, et al. The Impact of Myopia and High Myopia:Report of the joint World Health Organization-Brien Holden Vision Institute Global Scientific Meeting on Myopia, University of New South Wales, Sydney, Australia, 16-18 March 2015. https://www.who.int/blindness/causes/MyopiaReportforWeb.pdf.

Job Related Ocular Injuries

Ocular injuries from job related accidents are common. This presents a public health concern. According to the National Institute for Occupational Safety and Health (NIOSH), approximately 2,000 U.S. workers suffer a job related eye injury each day.^1,4  Of these injuries, up to 20% cause temporary or permanent vision loss.  According to information from Industrial Safety & Hygiene News, eye protection could have prevented, or diminished, the severity of 90% of these eye injuries.^2,4  Wearing protective equipment is the best way to prevent these accidents from occurring.

The most at risk jobs to incur an eye injury include construction, mining, automotive work, welding, manufacturing, plumbing and agriculture.²  Other jobs may put people at risk of acquiring diseases from infected bodily fluid droplets contacting another person on the mucous membranes around the eye.²

It is necessary for anyone working in, or around, areas with potential hazards to the eyes to wear protective eyewear that complies with the Occupational Safety and Health Administration standards for eye and face protection. OSHA requires employers to provide employees with appropriate eye and face protection whenever needed to protect against mechanical, chemical, environmental or radiologic hazards.³

Sources:

1. The National Institute for Occupational Safety and Health- Eye Safety. Centers for Disease Control and Prevention website. https://www.cdc.gov/niosh/topics/eye/default.html. Last Reviewed July 29, 2013.
2. Protecting your eyes at work.American Optometric Association website. https://www.aoa.org/healthy-eyes/caring-for-your-eyes/protecting-your-vision?sso=y.
3. Eye and Face Protection.Occupational Safety & Health Administration website. https://www.osha.gov/eye-face-protection.
4. 90% of workplace eye injuries could be lessened or prevented with safety eyewear use. Industrial Safety & Hygiene News website. https://www.ishn.com/articles/103615-of-workplace-eye-injuries-could-be-lessened-or-prevented-with-safety-eyewear-use. March 28, 2016.

Glaucoma

Glaucoma is a disease that damages the optic nerve of the eye. The optic nerve is the information portal from the eye to the brain. Damage from glaucoma is permanent and not reversible.

Glaucoma is a public health concern. Approximately three million Americans have glaucoma and it is the second leading cause of blindness in the world.³  Glaucoma usually does not cause symptoms until the later stages of the disease when a significant amount of vision is lost. Approximately 50% of people that have glaucoma don’t know they have it.⁴

A comprehensive eye exam is the only definitive way to make a diagnosis of glaucoma.²  Once a diagnosis of glaucoma is made, different treatments may be offered including medications and procedures.⁴  The goal of the treatments is to lower the intraocular pressures and slow/stop the progression of the disease. We have landmark glaucoma studies that demonstrate lowering intraocular pressures is of benefit in preventing the onset, or slowing the progression, of glaucoma. The Early Management Glaucoma Trial (EMGT) provided us evidence that patients with early glaucoma, who had their intraocular pressures lowered, experienced slower glaucoma progression and progression that occurred later when compared to patients that did not have intraocular pressures treated.¹

Sources:

1. Heij A, Leske M, Bengtsson B, et al.Arch Ophthalmol.2002 Oct; 120(10):1268-79.Doi:10.1001/archopht.120.10.1268.
2. Kierstan B.Glaucoma. American Academy of Ophthalmology website. https://www.aao.org/eye-health/diseases/what-is-glaucoma#risk. Last reviewed June 15, 2021.
3. Don’t Let Glaucoma Steal Your Sight! Centers for Disease Control and Prevention website. https://www.cdc.gov/visionhealth/resources/features/glaucoma-awareness.html. Last Reviewed November 24, 2020.
4. Glaucoma.National Eye Institute website. https://www.nei.nih.gov/learn-about-eye-health/eye-conditions-and-diseases/glaucoma. Last Updated July 28, 2020.

Age Related Macular Degeneration

Age-related macular degeneration (AMD) is a disease that damages the area of the retina (called the macula) responsible for sharp, fine-detailed central vision.  While early abnormalities may begin to develop in a person’s forties or fifties, more significant vision loss tends to occur in a person’s sixties or seventies and can continue to worsen with age.²  The condition affects approximately 11 million Americans and 170 million people throughout the world with these numbers expected to increase as our older populations increase.² AMD is the leading cause of permanent fine-detailed central vision loss in people 65 years and older, making it a public health concern.

There are two types of AMD, wet and dry. The majority of people with AMD (85-90%) have the dry form, leaving 10-15% to suffer from the wet form. Dry AMD (non-exudative AMD) is characterized by degeneration/thinning of the retinal pigment epithelium (RPE) and photoreceptors within the macular area. This is seen clinically as pigment changes of the RPE and accumulation of yellow deposits called drusen.⁴The wet form of AMD (neovascular or exudative AMD) is caused by atypical blood vessels growing from the choroid into the retina.⁴These vessels then leak blood and fluid into the retina causing distorted vision or blind spots. These leaking blood vessels can eventually lead to scarring of the macula and permanent central vision loss.⁴

Certain factors can place people at a higher risk of developing AMD. As the name suggests, age is a significant risk factor for developing AMD. The prevalence of advanced AMD has been found to increase with each decade of life, and is highest after 75 years of age.⁵Smoking tobacco can increase a person’s risk of developing AMD by 2-3x compared to a person that has never smoked.⁴Other factors that may contribute risk include hypertension, heart disease, high fat diet, low antioxidant diet, obesity and ultraviolet ray exposure.² Genetics have also been considered as possible risk factors for the development of AMD.

Different treatment modalities exist depending on the type and severity of AMD. AMD is categorized as early, intermediate or advanced based on the clinical findings.

Early AMD, as defined by the Age Related Eye Disease Study (AREDS), is small drusen (<63 microns in diameter), few medium drusen (63-124 microns in diameter) and/or minimal to no pigment epithelial abnormalities in the macula.⁷Currently, there is no recommended treatment for early AMD as AREDS did not show evidence to support the use of supplements for these patients.⁷

Intermediate AMD, as defined by AREDS, is extensive medium drusen (63-124 microns in diameter) or one or more large drusen (125 microns or greater in diameter) in one or both eyes.⁷Based on AREDS and AREDS 2, the rate of development to advanced AMD at 5 years is reduced in participants taking the combination treatment of antioxidant vitamins with zinc and copper.^6,7

Advanced AMD, as defined by AREDS, is either neovascular AMD or geographic atrophy that involves the center of the macula.⁷Again, based on both AREDS trials, the rate of developing advanced AMD in an eye without advanced AMD and a fellow eye with lesions of advanced AMD was reduced in participants taking the combination treatment of antioxidant vitamins with zinc and copper.^6,7

Treatments for neovascular AMD exist. As there are high levels of vascular endothelial growth factor (VEGF) causing the abnormal blood vessel growth, anti-VEGF intravitreal injections are typically the first line treatment for neovascular AMD.⁴Thermal laser photocoagulation surgery is a less common treatment for neovascular AMD. It involves firing a thermal laser at the abnormal blood vessels to destroy them.⁴

A treatment used for all forms of AMD is low vision rehabilitation. Optometrists and ophthalmologists that are trained in low vision help patients, who suffer from vision loss, learn how to better perform their daily activities independently.

As AMD is the leading cause of irreversible central vision loss in the western hemisphere ⁵, and as the population continues to age, AMD is, and will continue to be, a public health concern.

Sources:

1. https://www.nei.nih.gov/learn-about-eye-health/eye-conditions-and-diseases/age-related-macular-degeneration
2. https://medlineplus.gov/genetics/condition/age-related-macular-degeneration/#causes
3. https://www.cdc.gov/visionhealth/basics/ced/index.html
4. Gopalasamy K et al.Age Related Macular Degeneration: A Systematic Review. J. Pharm. Sci. & Res. Vol. 8(6), 2016, 416-420.
5. Hadziahmetovic M, Malek G.Age-Related Macular Degeneration Revisited: From Pathology and Cellular Stress to Potential Therapies. Front. Cell Dev. Biol. 2021 Jan. doi: 10.3389/fcell.2020.612812
6. The Age-Related Eye Disease Study 2 (AREDS 2) Research Group. JAMA. 2013; 309(19):2005-2015.Doi: 10.1001/jama.2013.4997.
7. Age-Related Eye Disease Study Research Group. Arch Ophthalmol. 2001; 119(10):1417-1436.Doi: 10.1001/archopht.119.10.1417.

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