Material and thickness: the important factors in the impact resistance of spectacle lenses

Can J Ophthalmol. 1977 Oct;12(4):300-3.


The identify the population at risk of permanent visual impairment from injuries associated with spectacles, we analysed 446 cases of penetrating ocular injury occurring over a ten year period. Sixteen injuries (3.6%) were due to spectacles; 40% of these were adult male amateur athletes. We used the drop-ball test to determine the important factors in the resistance to impact of 177 used spectacle lenses (29 plastic C39, 40 heat-tempered glass, 108 non-tempered glass). We found that material and thickness were the most important. The plastic lenses were the most impact resistant and non-tempered glass lenses the least, with heat-tempered glass lenses falling between. Plastic lenses of adequate centre thickness mounted in plastic frames are recommended for all children and all adults involved in athletics.

MeSH terms

  • Adolescent
  • Adult
  • Athletic Injuries / etiology*
  • Child
  • Eye Injuries / etiology*
  • Eyeglasses / standards*
  • Female
  • Glass / standards
  • Humans
  • Male
  • Plastics / standards
  • Risk
  • Sports


  • Plastics