Keratometry is a process used to measure the curvature of the cornea. It is performed by an ophthalmologist such as an ophthalmologist, using a device known as a keratometer or ophthalmometer. No special preparation is required on the part of the patient for a keratometry session, and the procedure is generally painless, unless a patient experiences difficulty lying still. The basic keratometer was developed in 1880, although the design has been significantly refined since then.
In a keratometry procedure, a device is used to measure the degree of curvature in the cornea, looking for the deepest and steepest curves. Most modern keratometers use computers and optical sensors, rather than forcing the doctor to do calculations, and the computer can compare the patient's cornea to a database of known measurements and typical norms. Ultimately, numbers will be produced so that the keratometry data can be recorded in the patient's medical record or passed on to other physicians.
One of the main reasons for performing keratometry is to check a patient's astigmatism, a vision problem caused by irregularities in the shape and curvature of the cornea, and to determine the degree of astigmatism. Using the numbers from the keratometer, the doctor can determine what options are available to correct astigmatism so the patient can see more clearly. The device can also be used to look for irregularities in the corneal shape between the eyes.
Before certain types of eye surgery, the surgeon may order keratometry to obtain a complete image of the eye, and the measurements may also be used to guide the procedure. It is also common to have sessions with a keratometer after eye surgery in order to follow the results of the surgery and monitor changes in the eye. Early identification of unexpected changes in the eye is critical as it can mean that an emerging problem is caught quickly.
As with corrective lens prescriptions, patients can take their keratometry readings with them if they wish to receive care from another physician. Patients can also request copies of their charts, something patients may want to do if they have complex eye problems and are moving to another area. Having a copy of the chart on hand can save a new ophthalmologist time and ensure that the patient receives the most appropriate care and treatment from the first eye appointment.