An eyelash curler is a hand-operated mechanical device for curling eyelashes for cosmetic purposes. Usually only the upper eyelashes are curled.
There were different patents of this invention between 1923 and 1940. The first known patent for the eyelash curler states that it was filed by Charles Stickel and William McDonell from Rochester, New York. However, William Joseph Beldue is recognized as one the first inventors while he was working in Kurlash Co., in Rochester, NY. William Beldue and his Kurlash Company held patents in Canada , the United States and Great Britain for the eyelash curler and improvements to it.
In the 1930s and in 1940s, at the top of the make up fashion, these curlers were very popular and not expensive. The eyelash curler was patented April 7, 1931 and the images drawn in the patent application look very much the same as the eyelash curlers seen on the market today. Originally named Rodal, the brand smartly changed the product’s name to Kurlash. 
Eyelash curlers are usually made of metal, and often have rubber pads where the curlers make contact with the lashes. The general design of these devices remains the same from 1940s. Manufacturers include ForteBellezza, Shiseido and Shu Uemura.
The two most common types of eyelash curlers are heated curlers and traditional eyelash curlers. Heated eyelash curlers deliver a more intense curl that lasts longer. However a simpler step to add to an eye makeup routine includes a more traditional, unheated eyelash curler. An unheated curler that is curved for the natural shape of an individual's eye includes a plentiful enough pad to press against eyelashes. Before using, an unheated curler can be heated for a short time with a hair dryer, but not to the extent to burn the delicate skin above the eyes. Self-heating, battery-operated units are available.
For traditional eyelash curlers, start by holding the curler like a pair of scissors and opening it completely. Keep your eyes open and bring the tool towards your upper lashes. Place your lashes in between the top and padded base, stopping as close to the root of your eyelashes as possible without pinching skin. For the first round of curling, keep your tool upright by the roots of your lashes. Check that all of your lashes are inside the curler.
To avoid a sharp bend and to create a natural curled look, gently release the curler and move it up the lash, away from the lid, by one or two millimeters, and again clamp the lashes for five to 10 seconds. Gently release the curler and repeat the process one or two more times, moving the curler up the lashes, closer to the end of the lashes each time. Continue avoiding a sharp bend by moving the curler slightly up the lashes away from the roots for another clamp. Lastly, wiggle the curler up towards the tip of your lashes and close down softly with the same pulsating pressure to complete the curl. An easy trick is to start with the lash curler at the base of your lashes and then do a slow blink. The pressure of the blink helps curl your lashes as they move through the curler.
If you're using a clamp-style heated curler, start crimping at the base of your lashes and then slowly ease the curler toward the ends. One swoop - from the base to upwards takes around 10 to 15 seconds, gently holding in certain areas to set the curl. It is the combination of heat and holding the position that creates the style of curl. Take time to bend the lashes back and push back to create the curl you want. Move slowly and experiment with the angles at which you hold it.
In order to create the effects of a heated eyelash curler with only the accessibility of a traditional one, a user can warm it up with a hair dryer. To get the best results, it is recommended to use it directly after warming up with a hair dryer because it lasts longer. When using heated eyelash curlers, it is very important to be cautious of the temperature the curler is heated to. To avoid the risk of burning the eyelid with the hot metal curlers, many companies have introduced plastic based curlers. Some companies are looking into introducing self-heated curlers to control the temperature and completely eliminate the risk of a burn.
To begin, warm up the curler and then curl the eyelashes for 10 to 15 seconds. Continue curling them until you have the desired shape. Next, apply more coats of mascara and curl the eyelashes once more for the final look. Repeat the application of mascara and curling of the lashes until the desired length is reached. Due to varying eyelash length, some users may need to apply mascara and curl the eyelashes multiple times.
An eyelash curler is a good makeup kit tool because it gives the illusion of bigger and brighter eyes and helps lengthen the eyelashes. When it is applied using different tactics such going heavier on the outer corner eyelashes, it gives a different and well-defined shape to the eyes. It is easy to use without professional training and is not very expensive to purchase. Additionally, it is not a very big tool, so it can be comfortably placed in the makeup bag.
A heated eyelash curler makes the curling process easier and an eyelash curl to last significantly longer. The heated element of the curler saves time and unnecessary pressure for a user, creating an easily curl without the need to hold the clamp down for long periods of time. Alongside this, the majority of heated curlers are wand-like, which means there's nothing pulling or pinching at your eyes. If a user has fragile lashes or lashes that are falling out, a heated eyelash curler will lift up eyelashes for a gentle curl without applying any force whatsoever. Heated eyelash curlers also tame and even out eyelashes that stick out in different directions, creating a flawless look for a user. 
Among many advantages, there are some disadvantages to the eyelash curler. If not used with care, pulling on the eyelashes while curling can lead to weakening of the roots. Many people can damage their eyelashes by holding down the clamp on their lashes for increased lengths of time, leading to their lashes either being pulled out or falling out due to the stress of continuous clamping. This may result in the eyelashes becoming weak and eventually lead to shedding which can be very bad for an eye because they protect the eye from wind and dust and don’t grow back quickly.
If not used carefully, eyelash curlers can lead to accidents where a user pinches the eyelid. Depending on the amount of pressure they apply, this can cause a serious injury to the eye. Similarly, when used warm, an eyelash curler, especially those made of metal, can cause serious burns to the eyelid. Also, some heated eyelash curlers require batteries to run, which will require maintenance to run in terms of replacement on time for smooth functioning.