Learn › Track 02 · Equipment & physics
Glasses, iris & blinders
Hold the pistol out and look along the sights. The rear notch is under a metre away, the front blade about a metre, the target ten. Your eye can only focus at one distance at a time. So which one gets it?
Think first: Front blade about 1 m from your eye, target 10 m away. What should be sharp while you aim?
- The target: that is where the shot goes
- The front sight: the target can stay a grey blur
- Switch back and forth between them during the hold
Toggle the focus and compare. With the blade sharp, the light gaps are crisp and you can see the smallest offset. With the target sharp, the blade turns fuzzy and the gaps smear.
This is why shooting glasses for pistol are unusual: they are not set for the target, they are set for the front sight. The eye-side technique is in eye dominance & focus.
A lens for the front sight
A young eye can focus on a front sight a metre away without help. As eyes age, that near focus gets harder, and the blade starts to blur. A lens fixes it by adding focusing power, measured in dioptres (D). The power you need is 1 divided by the distance in metres.
Think first: With your distance prescription in place, how much extra lens power do you need to focus at 1.0 m?
Try your own eye-to-blade distance:
Front sights usually sit about 0.9–1.1 m from the eye, and many shooters end up with an add of about +0.5 to +0.75 D on the shooting lens. These figures come from shooters’ experience. Have an optometrist measure your actual eye-to-front-sight distance in your shooting position and prescribe from that.
Shooting glasses are usually a frame with one lens holder in front of the aiming eye, set so you look straight through its centre in your head position. One common system takes 23 mm or 37 mm lens holders, and these also carry an iris, an eye shield or a polarising filter.
The iris
An iris is an adjustable hole in front of your eye, like the aperture of a camera.
Think first: You close the iris on your shooting glasses to a smaller opening. What changes?
- The picture gets brighter and the target blurrier
- More of the scene is in acceptable focus, but the picture gets darker
- Nothing optical: it only blocks glare from the side
Close it too far and the picture goes dim, and a dim picture is hard to read too. The iris also has to be centred on your line of sight through the sights.
Filters, blinders and both eyes
Coloured filters are used to raise contrast or cut glare under range lighting. The sources on which colour helps are unconfirmed, so try filters in training before you trust one in a match.
Think first: Your range has harsh lighting and you want a yellow filter. Where may it go?
- Clipped to the rear sight
- In your shooting glasses
- Either place: it's your choice
The other eye needs a plan too. The rules do not require either eye to be open or closed, but they do limit what you may put in front of it.
One front blinder, at most 30 mm wide, may cover the non-aiming eye. Side blinders are allowed in shotgun only, not at 10 m.
The usual coaching advice: keep both eyes open, with a translucent blinder or tape on the lens in front of the non-aiming eye. It blocks the view but lets light through, so both eyes get equal light.
The ISSF recommends that athletes wear shatterproof glasses.
- Focus on the front sight. The target is a grey blur, and the gaps must be sharp.
- Extra lens power to focus at distance d is about 1 ÷ d dioptres. Let an optometrist measure your real distance.
- A smaller iris gives more depth of field but less light. Keep it centred.
- Lenses and filters go in your glasses, never on the pistol.
- One front blinder up to 30 mm over the non-aiming eye; no side blinders at 10 m.