What are cataracts?
Cataracts are cloudy patches on the lens in the eye, which cause blurred vision and eventual blindness if left untreated. It is estimated that in the UK one in three people aged 65 has a cataract in one or both eyes.
Most develop due to age-related changes in the lens
- An imbalance between free radicals (unstable atoms that damage cells) and antioxidants (which keep free radicals in check). Cells in the body produce both, but smoking, drinking too much alcohol and exposure to chemicals can speed up production of the damaging free radicals.
- As we age, fewer antioxidants are produced, resulting in oxidative stress, leading to tissue damage; proteins and fibres in the lens start to break down and calcium builds up in the lens.
- Cataracts are also linked to conditions such as diabetes and to medications, includinglong-term use of steroids.
Current treatment
The current treatment is to replace the cloudy lens in a 30-minute operation under local anaesthetic. The cloudy lens is removed through a small cut in the eye, and replaced with a plastic one. About 350,000 cataract operations are performed in the UK each year.
New treatment developed
Scientists at US-based Nacuity Pharmaceuticals have developed a 'pellet' implant (NPI-002) that is injected into the eye to prevent cataracts forming, and might even reverse the growth of existing cataracts without surgery. This is now being tested in the first clinical trial.
- The implant is thought to work by lowering calcium levels in the eye.
- The implant is loaded with antioxidants and injected into the vitreous, the gel-like fluid between the lens and the retina (the light-sensitive area in the eye). The solution includes N-acetylcysteine amide (NACA), an effective antioxidant.
- The implant slowly releases its contents into the vitreous, which carries them to the lens where it acts on the cataract.
First clinical trial
An animal study by ophthalmologists at Washington University, US, and other centres, reported in the journal BMC Ophthalmology in 2018, showed that the implant prevented and reduced the severity of cataracts. It also led to an increase in protective antioxidants, and reduced calcium levels to 2.5 times lower than a control group.
The first human trial, in the US, will start soon (late 2021) and will involve 30 patients aged 65 and over with cataracts.
Initial interest in the implant is tempered with caution. Gwyn Williams, a consultant ophthalmologist at Singleton Hospital in Swansea, said "It is a very interesting idea and I look forward to seeing the results. Cataracts are multi-factorial and I am sceptical that this one approach will be effective by itself, though this remains to be seen."
Source: Scientists develop 'pellet' that can be injected into patient's eye to prevent cataracts forming - and could even reverse existing traces. Daily Mail (5 Oct. 2021)
