Pulling wool from their eyes

Thursday 2nd November 2023

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Cataracts are observed as a clouding of the eye lens, developing over time and affecting vision quality.

Cataracts are a part of the natural aging process and are observed as a clouding of the eye lens, which develops over time and affects the quality of vision. According to the World Health Organization, over 65 million people worldwide are living with cataracts, which is the leading global cause of vision impairment and blindness. Cataracts often develop between 40 and 50 years of age. By the age of 80 years, most people in Europe and the US either have cataracts or have undergone cataract surgery.

The vision clouding with cataracts is caused by a disorganisation of proteins in the lens that leads to protein clumping, resulting in light scattering and severely reduced transmission to the retina. Although development of cataracts is usually associated with age and family history, repeated unprotected exposure to UV radiation, as well as smoking and medical conditions such as diabetes, can amplify and accelerate the process.

Research suggests that eating foods high in antioxidants, such as vitamins C and E, may help reduce cataract development and progression. There are four clinical stages to cataract development.

1. Early cataracts produce hardly noticeable differences in vision and focus.

2. Immature cataracts occur when the lens is growing cloudier and more difficult to see through, and may be accompanied by blurred vision in low light.

3. Mature cataracts are visibly larger, and the pupil colour changes from black to a deep green. Blurred vision becomes more common, often with difficulty in activities such as driving at night.

4. Hypermature cataracts are associated with extremely blurred vision, and often blindness, and changes to eye colour and appearance (becoming yellow and clouded).

Most age-related cataracts typically develop relatively slow, over a span of years, and may vary based on the individual. Speed of cataract development can even vary between the two eyes in the same person.

Cataract surgery is the mainstay of treatment, relatively fast-healing, and is associated with an excellent safety profile. In the Developed world, surgery is widely accessible and only 5% of blindness is associated cataracts. However, in low- and middle-income countries surgery is less accessible, with cataracts accounting for half of all blindness, most often in women, and intrinsically linked with poverty.

During surgery, an artificial lens is surgically implanted to provide clarity, improve quality of life, and help restore vision. Cataract surgery is often recommended sooner rather than later to improve vision and reduce the risk for falls, injury, and other health problems due to poor eyesight. More advanced techniques are available for lens replacement surgical, including Advanced Laser-assisted Cataract Surgery, which uses a computer-guided femtosecond laser for each precise incision, customised based on a live 3D image during surgery. By contrast, in standard cataract surgery, all incisions are performed manually with a blade. Both standard and advanced methods are extremely successful and well-tolerated, with similar clinical outcomes.

Currently, there are no non-surgical treatments available to remove cataracts. However, in the first research of its kind, recent promising findings have shown that antioxidants and oxysterols improve or reverse lens opacity in mouse cataract models. In laboratory trials, treatment with a topical oxysterol compound showed an improvement in a key optical parameter (refractive index) in around 60% of lenses. This was associated with restoration of the protein organisation of the lens, resulting in improved focus. These results were supported by a reduction in the grade of lens opacity in almost 50% of cases.

Although in early stages, the development of a topical, non-surgical treatment to prevent cataract progression may have a significant impact on current treatment paradigms and patient quality of life.