Cataracts, the most common cause of human blindness, may one day be treated with eye drops rather than surgery.
A study headed by the University of California-San Diego (UCSD) published in the journal Nature illustrates how an eye drop solution containing a natural steroid reduced cataracts in dogs.
Our eyes’ lenses are largely made up of crystallin proteins, which serve two purposes: they allow us to alter focus and they maintain the lens clean. Nobody understands how they accomplish this.
Cataracts arise when the delicate structure of the crystallin proteins is disturbed, causing them to clump together and cloud the lens.
The lens is also high in lanosterol, a substance that is a key component of several important hormones in the body. An enzyme called lanosterol synthase produces lanosterol.
The researchers were interested in lanosterol after discovering that children with an inherited type of cataracts shared the same lanosterol synthase-blocking gene mutation.
They reasoned that in normal eyes, whose lenses are loaded with lanosterol, the clumping of cataract-forming proteins is prevented.
Lanosterol decreased clumping in cataract-forming proteins
Starting with lab cells and advancing to animals, the researchers conducted three sets of studies.
First, the researchers discovered that lanosterol reduced the clumping of cataract-forming proteins in human lens cells. They next demonstrated that treating rabbits with lanosterol decreased cataracts and enhanced lens clarity.
Cataracts: Some Quick Facts
- Risk factors include too much sun, diabetes, tobacco and alcohol.
- Most cataracts develop later in life
- Cataracts account for 51% of world blindness
Finally, they found that the lanosterol solution – in both injection and eye drop form – had the same impact in decreasing protein clumping in live dogs with cataracts as it did in human lens cells and rabbit lenses: cataracts were decreased and lens transparency improved.
The researchers come at the following conclusion:
“Our study identifies lanosterol as a key molecule in the prevention of lens protein aggregation and points to a novel strategy for cataract prevention and treatment.”
It might be a game changer if lanosterol in the form of eye drops proves to be an effective therapy for cataracts in people.
Cataract surgery is now the only technique to treat them. However, this is not a choice offered to everyone. According to the World Health Organization (WHO), there exist restrictions in many countries that prohibit people from receiving treatment, hence cataract remains the major cause of blindness.