Cataracts are the leading cause of blindness worldwide. Currently, the only way to treat cataracts is to have them surgically removed. Cataract surgery is one of the most common surgeries performed in Australia. Imagine if cataracts could be treated without the need for surgical intervention. What if surgery became a thing of the past and cataracts were treated with eye drops instead? Well this may sound like a bizarre plot in a science fiction movie, but scientists say it could well be our treatment modality in the near future.
The human lens is comprised of crystallin proteins which are assembled in a highly organised fashion essential for maintaining transparency and refractive power. The function of the lens is to transmit light and focus it on the retina. Disruption to the ordered structure of the lens proteins leads to unordered aggregation of proteins and subsequent formation of cataract.
View of clear healthy lens through pupil.
View of cataractous lens (yellow appearance) through pupil.
Researchers at the University of California, San Diego, have developed a topically applied treatment that has been shown to shrink and even dissolves cataracts. The new treatment has been researched and developed over many years and is based on the use of a naturally occurring steroid, lanosterol. Research has shown that lanosterol inhibits protein aggregation and cataract formation in rabbit and dog lenses in vivo. This is a very exciting technological development in potential cataract treatments because although surgery to remove cataracts is efficacious and safe, ageing populations around the world are predicted to require a two-fold increase in cataract surgery in the next 20 years. This would mean a significant impact on our public health system which is already struggling to cope with long waiting lists for cataract surgery.
It is very easy to screen for cataracts non-invasively with your general eye examination and as the eye is easily accessible for topical application of drugs, a pharmacological treatment for cataract is a promising thought for the future!
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Zhao, L., Chen, X., Jin, X., Lin, D., Wen, C., Abagyan, R., Su, Z., Gao, W., Kozak, I., Granet, D., Yan, Y., Zhang, K., Wu, F., Chung, C., Zhu, J., Xi, Y., Flagg, K., Wang, Y., Tjondro, H. Lanosterol reverses protein aggregation in cataracts: 2015. Nature. 523, 607-611.