In medicine, a speculum is an instrument that holds parts of the body open temporarily. As the eyelids blink constantly to relieve the dryness of the eye when it is open for too long, surgeries or diagnostic procedures are easier to perform with an eyelid speculum keeping the eye open for longer than usual. Examples of situations where an eyelid speculum may be used include laser eye surgeries, cataract removal operations and some eye examinations.
A variety of medical procedures involve the use of a speculum, as many parts of the human body have orifices or cavities that are protected either by a closing mechanism, like the eye, or a flexible tissue wall, such as the ear canal. As these areas require a tool to open the cavity further or for longer than usual, the medical profession invented the speculum. Typically, a speculum has handles for the doctor to hold, which are attached to a set of jaws that are either flexible within a certain opening range, or which can be set to a specific opening width.
The eyes and eyelids are very delicate. An eyelid speculum, therefore, needs to be light and have blunt edges so as not to damage the area. Specula to hold the eyes open come in two main forms, which are suitable for different uses. One is the wire speculum, which is made up of flexible wire that can hold the eyelids open, but which is not adjustable for individuals. The other is the rigid speculum, which has an opening range that can be set by a mechanism like a screw, which is a useful feature when dealing with a range of eyelids such as those found in growing children.
Specula can be reusable or they can be disposable. Commonly, an eyelid speculum is made out of a metal like steel, as plastic can shatter more easily, and produce damage to the eye area. During a procedure, the surgeon or the ophthalmologist inserts the speculum between the top and bottom eyelids of the patient, who may or may not be under general anesthetic.
Surgeries that typically involve the use of an eyelid speculum include laser eye surgery for vision improvement and cataract surgery. A local anesthetic eye drop is commonly used during operations like these. A potential risk of the use of an eyelid speculum is that the top eyelid may become weaker and droopier than normal. An ophthalmologist who needs to perform an eye examination without the interruption of blinking may also use an eyelid speculum.