Every Thoroughbred racehorse is an individual athlete with his or her own unique abilities and personality quirks. While saddles, stirrups, bridles, and bits are standard gear worn by every horse when they compete in order for their jockeys to ride them and control their movements, some horses improve with added headgear such as blinkers.

Blinkers are cups usually made of plastic that are fitted to a hood placed on a horse’s head. They are positioned near each eye and are used to limit a horse’s vision when he/she runs.

Why would a horse need blinkers to limit vision? Because some horses are more easily distracted than others, and blinkers prevent them from seeing what’s behind or next to them during a race. Horses have eyes positioned on each side of their head and therefore have near-panoramic vision – the only places they cannot see are directly behind and right in front of their nose.

A trainer will therefore add blinkers to a horse to improve focus during a race, which could help a horse who has early speed break better out of the starting gate and use that speed to set the pace, or help a horse that prefers to come from behind in races relax early on and focus on the targets in front (other horses) it will try to pass in the homestretch. The blinkers can be cut to various lengths depending on how much vision a horse’s trainer wants to restrict. Keep in mind that just as blinkers can be added, they can also be removed from a horse that has been wearing them while racing, if the trainer believes they are starting to hinder his or her ability.

When the equipment change works as intended, a horse’s performance can improve by leaps and bounds. For example, current Kentucky Derby contender Burnham Square finished second and third in his first two races and was positioned far back in the field both times before rallying late. Trainer Ian Wilkes then added blinkers to Burnham Square, and in his subsequent two races the gelding was positioned much closer to the early lead and won both times by a combined margin of 10 ¾ lengths.

Bonus Explainer: What is a shadow roll?

A shadow roll, or piece of fleece attached to the noseband of a bridle, is a piece of equipment that also limits a racehorse’s vision so that it doesn’t try to jump shadows on the track if/when it encounters them, which would slow it down.