The eye is subject to high levels of oxidative stress because -of course- a lot of radiation is falling in, while the lack of blood flow to the retina means it has a reduced supply of antioxidants. Since tocotrienols can penetrate tissue even without their own transport molecule (TTP), they could play an important role in protecting the eye.
We have good studies for Macular degeneration, in which the macula is damaged by angiogenesis - newly created capillary blood vessels. The tocotrienols, which act against angiogenesis, act against this damage in the eye. The same applies to retinopathy caused by diabetes. [PMID 19702331,PMID 19071006].
For cataract, there is an animal study which proves the effectiveness against cataracts, but only in relatively low concentrations (0.02 to 0.03% T3 in direct application to the eye) [PMID 24940038]. A second study from 2017 demonstrated its effectiveness in cataracts caused by diabetes [PMID 28350848].
The usability of tocotrienol (but not of conventional vitamin E - alpha-tocopherol) in topical application to the eye was confirmed in [PMID 15506242].
Since tocotrienols also penetrate skin and tissue, topical application should also be effective on the skin around the eye rather than in the eye itself.