The optical coherence pachymeter (OCP) is a state-of-the-art device for determining the thickness of the cornea (cornea of the eye). The procedure is used in a supportive role to calculate intraocular pressure, which is particularly important in glaucoma diagnosis. Glaucoma is a disease caused by increased intraocular pressure. As it progresses, this pressure primarily damages the optic nerve and can lead to blindness.
Indications (areas of application)
- Suspicion of glaucoma
- Elevated intraocular pressure – without other signs of glaucoma.
- Normal intraocular pressure – but with conspicuous optic nerve findings.
The procedure
During glaucoma screening, intraocular pressure is measured using a technique called tonometry. Specifically, the procedure of applanation tonometry is based on the measurement of the force required to flatten the cornea with a flat surface (equipped with sensors) 3 mm. The basis of this determination of intraocular pressure is the assumption that the cornea has an average thickness of 0.550 mm. However, individual corneal thickness varies and can falsify the result. If the cornea is thinner than assumed, tonometry measures too low a pressure. The actual pressure is higher. Conversely, a thicker cornea results in elevated values, while the correct intraocular pressure is lower.
The optical coherence pachymeter allows accurate measurement of the true corneal thickness. The intraocular pressure can be correctly determined based on the calculated data. The pachymeter achieves very high measurement accuracy by using invisible laser light. The corneal thickness can be measured down to a thousandth of a millimeter.
In contrast to ultrasound pachymetry, the optical coherence pachymeter does not touch the eye during treatment. For this reason, local anesthesia (local anesthetic) is not necessary. The procedure is painless in its entirety and the patient can immediately return to driving. The examination time is very short and involves little effort for the patient.
The optical coherence pachymeter is a highly precise method for determining corneal thickness. It is important for the diagnosis of glaucoma and the subsequent course of therapy.