Post date: 
Tuesday, 21 October 2014

Hannah Flynn takes a look at research into the causes of myopia and cataracts.

Myopia increases with education

Higher levels of education are associated with higher levels of myopia in Europeans, a study in Germany published in Journal Ophthalmology has shown.  

The study looked at more than 4,600 Caucasian participants between the ages of 35 and 74 and showed that higher levels of school and post-school professional education are associated with higher levels of short-sightedness, or myopic refraction. Participants with higher educational achievements were more frequently myopic than individuals with less education.

One potential reason for this is that “near work”, like reading a book or a computer screen, can cause the eye to grow and get longer, causing myopia, explains researcher Dr Alireza Mirshahi, from University Medical Center in Mainz.

The phenomenon was already being studied in East Asia, he added. “They are studying classes where some children spend more time than normal doing outdoor activities to see if they are less myopic than those who stay indoors,” Mirshahi explained. 

Researchers also looked at the effect of genetics on myopia, but concluded that it had much less impact on the severity of near-sightedness than education level, according to the study.

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Cataract formation explained

A reason why UV light exposure can lead to cataract formation has been discovered by researchers and is reported in the Journal of Biological Chemistry. 

The study shows that UV light can damage lens proteins in a distinct way (called glycation) that can cause clouding of the lens, leading to cataracts. 

The theory had been suggested before. However, the team at Case Western Reserve University in Cleveland, Ohio, were the first to demonstrate the chemical changes caused by UV light hitting the lens.

Young human lenses (matching pairs of 20- to 36-year-old lenses from donor eyes) were used in the study, as well as lenses from one-month-old mice. Lenses with and without cataracts from donors age 58 to 76 years were also studied.

UVA light caused more damage than UVB light, the study concluded. 

An antioxidant that occurs in the eye and other tissues, called glutathione, offered little protection against the damaging effects of UV light. Other clinical studies have looked at using antioxidant supplements to prevent or slow age-related cataract, with mixed results.

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Over-40s could be risking preventable sight loss

Over half of people in the UK aged over 40 do not get an eye test every two or three years, despite free eye tests being available to groups most at risk of glaucoma, the International Glaucoma Association (IGA) has shown in a survey

The survey of 1,039 respondents over the age of 40 in the UK was conducted earlier this year by Fly Research Ltd for the IGA. 

Failing to get eyes tested regularly could lead to glaucoma being left undetected, which could lead to preventable sight loss. Russell Young, CEO, IGA, commented: “Glaucoma has commonly been described as tunnel vision, yet this is rare. It is far more common for people to experience patchy or misty vision in places.

“Encouragingly, our research shows the role of the optician as a health professional is largely understood, with the majority (89 per cent) being aware that the optician can detect eye conditions that can lead to loss of sight if not successfully treated”.

Remote screening investigated in premature babies 

Remote screening using photographs of infant retinas could be used to detect retinopathy of prematurity, a condition that can cause blindness in premature babies, it has been reported in the journal JAMA Ophthalmology.

In the study, which took place in the US, a total of 1,257 babies born 13 weeks premature on average were examined every nine days or so by ophthalmologists, and photographs taken were sent to a remote imaging centre. 

Staff using remote screening were able to correctly identify 90 per cent of ophthalmic referrals from photographs, in a study funded by the US National Institute of Health (NIH). 

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