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Professional Arena

 

Glaucoma, low light and winter blues 

Winter is quickly approaching - meaning more time spent reading, watching films and staying cosied up indoors. With shorter days too, we’re also more likely to be driving at night, having to manage contrast and navigating getting around in lower light. 

Naomi Meltzer is an Optometrist and Low Vision Consultant. Here, she discusses the subtle changes that happen to our eyes as a result of glaucoma and general aging, and how to cope with these changes during winter.

As winter rolls in, we turn our thoughts to cosy indoor activities like reading, movies, theatre and spectator sports, or a shopping trip to a bright and glittery shopping mall.

We usually think of the effect of glaucoma as being a reduction in peripheral vision. That leads us to believe that as long as the condition is being well managed medically and the visual field remains relatively unchanged, we continue to function visually as we have always done and assume that reading and other tasks that require detailed central vision will remain unaffected.

The reality is that there are subtle changes that take place beyond the normal aging process which are common to all optic nerve conditions including glaucoma, as well as other neurological conditions. These changes may include reduced contrast sensitivity, increased glare sensitivity and reduced dark adaptation.

CONTRAST is how we detect print or objects standing out from their background. It is the difference in the intensity of print and the intensity of the colour of the background it is printed over. Maximum or “high” contrast is black letters on a white non-shiny background or white letters on a black background, which is often more comfortable for people who are sensitive to glare. The effect of reduced contrast sensitivity is that the world takes on a washed out look which is often described as blur. If there are other conditions such as cataract stopping the light from getting a clear path to the retina at the back of the eye, this will add to the loss of contrast.

To enhance contrast, we can add more light by placing a lamp close to a task so that the light is directed onto the area to be seen. We can also use contrasting colours to highlight details e.g. using a contrasting strip of paint or tape to highlight the edge of a step will make it easier to see and therefore safer. Many people are finding electronic magnifiers which convert low contrast or coloured print to high contrast to be very helpful. Internally lit computers, telephones or e-readers also give enhanced contrast, which is welcomed by people affected by glaucoma.

GLARE SENSITIVTY is that horrible discomfort some people get when there is too much light coming into the eyes from the wrong angle – particularly reflected light from shiny surfaces, water, concrete, or low clouds on a wintery day.

We need light to help us to see. But people with glaucoma are often extra sensitive to glare, preferring to turn off lights and pull down the blinds for extra comfort or wearing dark sunglasses which not only cut out glare but also the light that is required to see with.

The answer is to have control of the light by using devices like polarised lenses with lighter tints, which can often also enhance the contrast. They also help to cut out the glare without reducing the light getting through as much as a dark lens will. Use directional lamps, torches or internally lit magnifiers and cover shiny surfaces to reduce glare.

DARK ADAPTATION is the ability to see in the dark. Glaucoma affects the peripheral retina – which is also the part of the retina that we switch on and use when it gets dark. This means that vision is worse in the dark and it takes longer than normal to adjust from a brightly lit room to a dark hallway or movie theatre. Carrying a small torch or using the light from a mobile phone can be very helpful to light a step, a keyhole, or a dark cupboard.

Most of these subtle changes will not be measured by the vision on the distance chart at the doctor’s room or the familiar peripheral vision tests. However, an awareness of these changes – and the strategies and aids available to counteract them – can increase safety and reduce frustration. Getting enough light (particularly sunlight) can also significantly improve  feelings of wellbeing in winter as well.

Certainly, just magnifying print is not the answer and sometimes magnification can make things harder to see for a person with significantly reduced peripheral vision.

It is not all about size!

Have more questions about managing your vision during winter? Email us at info@glaucoma.org.nz or freephone us on 0800 452 826. We’d love to hear from you! 


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