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Wednesday / December 19.
HomemieyecareProtective Eyewear for Myopia

Protective Eyewear for Myopia

The rising tide of myopia brings with it a range of health and economic consequences, both to individuals and to the broader community. Effective eye protection can reduce the risk of mechanical trauma and UV damage to myopic eyes.

Recent modelling predicts a significant rise in myopia and high myopia with an anticipated one billion people predicted to have high myopia by 2050.1 Physiological changes associated with myopia, including the eyes lengthening, are associated with sight threatening eye diseases such as retinal detachment and degeneration. When prescribing for myopes it is important to consider their eye protection needs, to prevent eye injuries associated with mechanical trauma as well as exposure to ultraviolet light from the sun.

Eye protection for high myopes should be considered for moderate to high risk activities

PROTECTION WHILE OUTDOORS

The association between time spent outdoors and the development of myopia is receiving increasing attention. The role of near work has also been implicated in the development of this ocular condition.

Figure 1: The Health Promotion Board of Singapore has developed campaigns to encourage children to “go outside and play”.

The work of Australian researcher Professor Katherine Rose represented some of the first contemporary data examining the effect of outdoor activity on the prevalence of myopia.2 After adjusting for ethnic, genetic, and near work factors, Rose et al concluded that increased time spent outdoors was associated with less myopia and more hyperopia.

There is also increasing evidence to show that the environment plays a role in the regulation of eye growth, though the exact environmental factors are still unclear. Recent data from Australia showed that for young adults, greater time spent in bright light was associated with slower longitudinal axial eye growth.3 A range of interventions and studies are also examining the consequences of outdoor activity and ambient light levels.

Armed with this knowledge about the protective role of light and outdoor activity, children are being encouraged to spend more time outdoors particularly in countries like Singapore.

Some questions have been raised about whether the use of sunglasses will reduce the effective level of light when outdoors. Researchers at Singapore Eye Research Institute conducted an evaluation of light levels in different environments to simulate wear by a 10 year old child (S.M Saw, unpublished). The effects of wearing a hat and different categories of sunglass transmittance on light levels reaching the eye were examined. The study concluded that children should be encouraged to spend more time outdoors to prevent myopia, and that sun protection in the form of hats or sunglasses was advisable.

In Australia it is particularly important to protect the eyes from glare and ultraviolet radiation because time outdoors typically involves high intensity light. Ultraviolet (UVA and UVB) light is known to cause damage to the cornea, lens, and conjunctiva. Optical filters in the form of sunglasses, spectacles, or contact lenses can provide an effective barrier to protect the eyes. In Australia, the sale and supply of sunglasses is legislated. All sunglasses must therefore meet the Australian Standard (AS1067.1), which requires adequate levels of UV protection.

SPORTS AND EYE PROTECTION

Recently published studies indicate a rising incidence of ocular trauma associated with sports and recreational activities in developed countries. One US study found that despite an overall reduction in emergency department visits for children, sports related eye injuries had increased by 12.8 per cent.4 Another study found that the most common sports related eye injuries in children under 17 years old were associated with basketball, baseball, and softball.5

Table 1. Sports activities by risk profile. *UV protection

Prevent Blindness lists basketball as the largest contributor to sports related eye injuries in those over 15 years of age and the second largest contributor in those under 15 in the US. Eye protection, introduced in the United States for high school students playing baseball, field hockey, and ice hockey, has reduced the rate of eye injuries. While cricket is not generally considered a contact sport, notable examples of professional sports people suffering an eye injury from a fast bowl should encourage players to wear eye protection, particularly when batting. A face guard attached to a helmet is the best form of eye protection in this case. One memorable cricket injury occurred when, during his time as Prime Minister, Bob Hawke was batting during the Prime Minister’s first eleven cricket match. His glass spectacles shattered when contacted by the ball, with the glass splintering and entering his eye. A timely reminder to wear the appropriate level of protection when participating in sports, which at a minimum should include impact resistant lenses to avoid such an incident. Fishing presents a unique combination of hazards with a weighted sharp projectile launched at speed, which can result in devastating open and closed globe injuries. Children, who are often spectators and at a more susceptible height, are at risk of injury while fishing and should be encouraged to wear sunglasses with impact resistant lenses.

EYE PROTECTION – WHEN AND WHAT?

It is important to ensure the correct level of eye protection is prescribed for your myopic patients, according to the level of risk associated with activities they undertake. High myopes in particular are at risk of retinal detachment (Figure 2).

Table 1 identifies sports by risk category. Eye protection for high myopes should be considered for moderate to high risk activities. Additionally, they should be counselled against some sports involving significant body contact, such as martial arts and boxing, because effective eye protection is not available.

The lens material you prescribe is vital as lens fracturing is a secondary hazard to the wearer. A potentially blunt injury can convert into a devastating penetrating eye injury when a person is wearing lenses that can fracture or shatter under impact. The consequences of any resulting open globe injury are more likely to result in significant vision loss. Impact resistant materials such as Polycarbonate and Trivex should be the material of choice.

Figure 2: Recommended eye protection based on individual and their activity risk factors.

Currently there are no sports eye protection standards in Australia. The Australian Standards for racquet sports (AS/ NZS 4066)6 and faceshields for cricket players (AS/ NZS 4499) have been withdrawn. For cricketers it is recommended that they use an integrated faceguard with their helmet, ensuring adequate coverage to prevent the ball entering while balancing the need for sufficient visual fields.7 For other sports, such as basketball, softball, and lacrosse the United States has standards intended to protect participants in these sports. A range of American Society for Testing and Materials (ASTM) standards are available and include eye protection for skiing (F659), paintball (F1776-18), field hockey (F2713-14), motor sports (F2879- 18), and for woman’s lacrosse (F3077- 17). Currently there are International Organization for Standardization (ISO) standards in development for racquet sports and downhill skiing, and ASTM standards for football, baseball, softball, and handball.

COUNSELLING AND GUIDING YOUR PATIENTS

Optometrists and ophthalmologists play an important role in guiding patients to appropriate eye protection. When prescribing everyday spectacles, always recommend an impact resistant material for all at risk patients, including children and high myopes.

Anyone who has young children will appreciate a child’s desire to fit in! In the absence of adequate role models wearing eye protection in sport, ensuring your younger patients feel comfortable wearing the eyewear you recommend as being most appropriate for their sport may be a challenge. To maximise compliance, practices need to carry a range of protective eyewear and take the time to help patients choose a frame that fits comfortably and looks good.

Annette Hoskin is a Research Fellow at Save Sight Institute, The University of Sydney and the Lions Eye Institute, University of Western Australia, the Standardisation Manager for Essilor and the Australian representative to International Standardization Organization committees relating to eye protection, sunglasses and spectacles. Her previous roles include regulatory and compliance assessment of sunglasses, spectacles and eye protectors, technology transfer and corporate development. Ms. Hoskin combines her experience and knowledge in the design and development of eye protection with in-depth understanding of the incidence and epidemiology of ocular trauma to help develop effective injury prevention strategies. She is widely published internationally in ocular trauma and the development of eye injury prevention strategies. 

References 

  1. Holden BA, Fricke TR, Wilson DA, Jong M, Naidoo KS, Sankaridurg P, et al. Global Prevalence of Myopia and High Myopia and Temporal Trends from 2000 through 2050. Ophthalmology. 2016;123(5):1036-42. 
  2. Rose KA, Morgan IG, Ip J, Kifley A, Huynh S, Smith W, et al. Outdoor activity reduces the prevalence of myopia in children. Ophthalmology. 2008;115(8):1279-85. 
  3. Ulaganathan S, Read SA, Collins MJ, Vincent SJ. Influence of seasons upon personal light exposure and longitudinal axial length changes in young adults. Acta Ophthalmol. 2018. 
  4. Matsa E, Shi J, Wheeler KK, McCarthy T, McGregor ML, Leonard JC. Trends in US Emergency Department Visits for Pediatric Acute Ocular Injury. JAMA Ophthalmol. 2018;136(8):895-903. 
  5. Miller KN, Collins CL, Chounthirath T, Smith GA. Pediatric Sports- and Recreation-Related Eye Injuries Treated in US Emergency Departments. Pediatrics. 2018;141(2).
  6. Standards Australia AS/NZS 4066- 1992. Eye protectors for racquet sports. 
  7. Standards Australia AS/ NZS 4499.3- 1997. Protective headgear for cricket. Part 3: Faceguards.