Final answer:
Severe damage to the eyeball from a direct blow is typically caused by a force similar to a 680-g mass, leading to increased intraocular pressure and structural trauma. Conditions like glaucoma and cataracts as well as photo keratitis from UV exposure are related eye health issues. Protective eyewear is essential in preventing such damage.
Step-by-step explanation:
The likely mechanism for severe eye damage from a direct blow to the eye involves a combination of increased intraocular pressure and physical trauma to the eyeball's structure. A force equivalent to the weight of approximately a 680-g mass (around 1.5 lb) resting on the eye can cause significant damage.
Normal eye pressure is much less, equivalent to a weight of about 120 g. In older individuals, particularly those over 40, the risk of glaucoma increases, which is a condition associated with high intraocular pressure. This pressure can be measured via tests that gently exert force on the eye or use a puff of air to measure the eye's deformation and rebound response.
Moreover, long-term exposure to UV-B light can lead to the formation of cataracts and other eye issues such as photo keratitis or arc eye. Excessive UV exposure also poses a risk of suppressing the immune system. Pertinent eye protection, such as sunglasses, is crucial in preventing damage from UV light.