Corns are one of the most common foot problems, and they can also be one of the most painful. Corns are calluses, patches of thickened dead skin, and they show up as raised bumps on the foot. The center is usually hard and the area around it often becomes inflamed, which can be very painful when pressure is applied.

Calluses are caused by constant friction or pressure that isn't strong enough to cause a blister. What makes corns different from other calluses is the pattern of the friction. Corns form when pressure is applied in an elliptical pattern; this often happens when badly fitting shoes rub against the feet. The central point of the pattern becomes the center of the corn. While a normal callus is often painless and can protect against further friction a corn is different; its hard center results in it being pressed painfully into the foot.

Corns can be easily treated by shaving away the dead skin at the center, which will immediately reduce pain. The problem is that if the pressure continues the corn will quickly regrow, so the treatment has to be constantly repeated. A common home treatment is the use of corn plasters. These are sticking plasters with a thick felt ring on the back, which are placed around the corn. They come in a variety of sizes to suit large or small corns, and work by preventing pressure being applied to the corn itself. Many modern ones are also impregnated with chemicals such as salicylic acid, which can soften the corn and reduce the effects of pressure. There are some issues with corn plasters, though. They need to be replaced daily so the cost can add up quite fast, especially if you have several corns. They also can transfer the pressure from the corn itself to the surrounding skin, which can become irritated by this.

A better solution is to prevent corns from occurring in the first place, and fortunately this is actually very easy. The key is to reduce the pressure and friction that causes them in the first place; more specifically, you need to prevent pressure from acting in an elliptical pattern. This means keeping the feet secure inside your shoes to prevent repeated patterns of movement happening. Obviously you don't want to wear shoes that are too tight, because this is painful and causes lots of problems of its own, so the key is to use a properly fitted custom insole.

A custom insole is moulded to the exact shape of your foot, so it acts as a support that holds your foot in the proper position inside the shoe. This can prevent corns forming, and if you've already suffered from one and had it removed it should stop it from growing again. Of course it also prevents other symptoms of pressure or friction, like blisters and raw skin.

In the past custom insoles needed to be ordered from a podiatrist and getting them fitted meant taking plaster casts of the feet then using these to create moulds. Technology has made it a lot simpler though - and as simple means cheap, costs have fallen too. This means that you can now afford custom insoles for every pair of shoes you regularly wear, and that will save you money too because constant removal is bad for insoles and shortens their life.

The new patented process uses two key pieces of technology. The first is image recognition, which can build up a 3D computer model of an object from multiple photographs. To design your insoles all you have to do is take three photos of each foot using either a smartphone app developed for the purpose or a standard digital camera. A computer then combines these into a perfect model. The model is then recreated in plastic by a 3D printer and it's this plastic version that becomes the mould for your insoles. Because the model exactly replicates the size and shape of your feet it guarantees a secure fit in your shoes, and no more friction.