GBRT : Canada 2011

Age, the eye, and how to compensate.

If, like myself, you find you are now eligible for SAGA holidays and are considering a cruise rather than an overseas tour, give me a moment of your time and I will try and explain why your sight picture is more elusive these days, and what we can do to compensate for it.

Age related changes within the eye affect everyone, to varying degrees, and can make significant changes to your sight picture, your accuracy, and hence your enjoyment of shooting: The crystalline lens inside the eye continues to grow and change shape throughout life – this only really becomes apparent to most people in their 40’s, when focusing on things close can become difficult. Time for your first reading glasses? Also, the colour of the lens becomes browner, meaning contrast sensitivity reduces and acuity in low light will deteriorate. However slight at this stage, this is progressive, and can eventually develop into a cataract (i.e.) the formation of opacities in the lens structure, mostly in the 60’s and 70’s.

Potential Problems

The inability to change focus from far to near (like you used to be able to) means that the aperture settings of the front and rear sights will need to be changed from those that have served so well for decades! The rear sight needs to be as small as possible, in order to increase depth of focus (have the foresight and target both as close to in focus as possible). This can be counter intuitive, as going bigger lets more light in and makes the picture look clearer: Beware; this is the most common catastrophic error!

My method is to close down the rear aperture, whilst on aim, until the sight picture goes dark and cobwebby - this is too small, now come back up in size very slowly until the cobwebby appearance disappears but it is still a little darker than you would like: This is the correct setting. The actual size will depend on eye relief, altitude and brightness, pupil size, etc, but will probably be around 0.7 to 0.9. Using over this size in anything other than very low light is probably a mistake!

If it is difficult to get foresight and target in focus together, a compromise will have to be made. It is much more critical that the foresight is clear and black than you have a crisp target. We have all shot in torrential rain or misty & foggy days, and been surprised to achieve groups difficult to achieve on a clear day! My point being, the eye will centre a fuzzy blob every bit as clearly as a crisp black one, providing the foresight is clear. To this end, if you wear an optical correction, you may want to adjust your prescription to achieve this. If this causes the target to be out of focus, fitting it into the same foresight aperture may no longer be possible: it may be necessary to go bigger, probably at least .2 or more.

As contrast sensitivity in the eye reduces, the size of the pupil in the eye also gets smaller, so considering filters may become an issue. It’s difficult to be proscriptive on this issue as there is a significant element of personal preference. However as a general rule; yellow/pink tints enhance contrast between the aiming mark and its background (particularly in hazy conditions) and grey/green tints will help with glare on sunny & bright days.

As the crystalline lens continues to age, and early opacities develop, you may find that in certain light conditions you find one part of the sight picture is distorted. E.g. The top right edge of the aiming mark, and possibly the foresight ring, are distorted and to see a circular aiming mark you have to look off centre through the rear aperture. Effectively what you are doing is looking around the cataract which is causing the distortion. At this stage the opacity can be so small as to be very difficult for your eyecare consultant to see it, and they will be at a loss as to what the problem is. So what to do? Well, in the longer term, the cataract operation is the most commonly carried out procedure in the UK (and probably in the western world) so it is not something to be scared of. But of course you are going to need specialist and shooting sympathetic advice. In the shorter term the best bet is optical correction and a lot of experimentation.

Age related changes in the eye don’t finish with the lens; floaters become much more common and can be a real nuisance, basically these are bits of debris in the jelly inside the eye (the vitreous humour). These bits cast a shadow on the retina and appear as translucent grey blobs of differing size and shape, more easily seen against a bright background like the target! Try dealing with them by looking down while waiting for your shot. Then when coming on aim, if they are interfering too much to cope with, try looking off to one side and back again: this should move the floaters for long enough to release the shot. Good luck!

Editor’s Note: Moving floaters are far less of a problem, and you may not even notice them if you rapidly flick your eyes from side to side a couple of times: they’ll be moving too fast to really disrupt the sight picture... (Doing this vertically may make the problem worse, though.)

At the back of the eye is the retina and in the central point is the maculae, the bit that has the highest concentration of receptor cells to enable accurate vision, the problem here is that it deteriorates with age. ARMD (age related macular degeneration) is the biggest cause of blindness in the world, and once damaged, it is time to try coaching or range officering.

On this, I can only advise a healthy diet, lots of coloured fruit and veg, lots of anti-oxidants and STOP SMOKING!

What can be done?

So, you’ve been shooting for years and your local optician has given you a lens that helps (if they have adjusted the lens to allow for focusing the foresight, and for the back vertex distance due to eye relief, and for the astigmatism axis due to head posture on aim). But it’s still difficult to make out the 1000 yard number boards and the score indicator board. What next?

Eagle eyes are widely in use now (rightly or wrongly is a subject for a different day!) Will that help? Almost certainly: they can significantly magnify the sight picture (requiring a much larger foresight aperture size) but you’ll feel like a teenager again! You may however have to change the power of the correcting lens (in your shooting glasses or other lens at the back) as over correcting to enable a clear foresight aperture, in conjunction with the low plus power eagle eye lens, will result in an image too blurry to shoot at!

Simply put, if you try an eagle eye (such as the “right sight” or any of the similar, large diameter eagle eyes) and it’s blurry, then it can be improved. However you should also consider the multitude of issues raised by these appliances: they sit higher above the barrel (so the sightline is higher and may require a change to the stock and cheek piece which means the bolt cannot be opened), they increase wind buffeting, and so on it goes… Striving for improvement is never easy!

Now the target is looking clearer, what next? Well, the problem is seeing your plot: the shooting lens is a distance correction, so will you need a reading lens as well? Also, your non shooting eye can’t really make out the flags clearly anymore, so how do we fix that? I use a bifocal lens in the left eye to solve these problems but there is an added benefit, in that by using my left eye for the scope (with a bifocal) I can see the mirage in two parts of the range at the same time! So which is better? Shooting glasses, contact lenses, a lens in the backsight or attached to it, dioptre, eagle eye, laser refractive surgery (now there is another choice!), cataract operation, what’s an ageing shooter to do? All of these options are the best option for someone, but we are all different and for good advice, find a shooting optometrist who understands your needs and can help you compensate for the changes that inevitably come with age. The good news is that most of the difficulties you will encounter can be helped.