This is the measurement of the corneal thickness. The cornea is the front clear window of the eye and covers the iris; the colored part of the eye. On average the cornea is about 550 microns thick or just over ½ mm. Patients with thinner corneas are at greater risk for glaucoma. and so this measurement is part of a baseline OCT measurement. The cornea can also become thicker or thinner with different corneal problems. For patients interested in laser refractive surgery the corneal thickness is a major factor in determining if they are a good candidate.
Our office has two methods of determining the corneal thickness. A hand-held pachymeter requires a drop of anesthetic and then the probe gently touches the eye for a few seconds to determine the thickness using ultrasound. Alternatively the OCT can measure the corneal thickness without touching the eye, using light reflections.