CPT® Code 92136

Ophthalmic biometry by partial coherence interferometry is a specialized diagnostic procedure utilized primarily in the preoperative assessment of patients undergoing cataract surgery. This technique is essential for determining the appropriate intraocular lens (IOL) power required to achieve optimal visual outcomes post-surgery. The procedure is also known by other terms such as optical coherence biometry (OCB) or laser Doppler interferometry, reflecting its reliance on advanced optical technologies. During the biometry process, three critical measurements are obtained: the axial length of the eye, the corneal radius, and the anterior chamber depth. The axial length is specifically measured using partial coherence interferometry, which employs a laser Doppler to illuminate the eye. This method involves the use of a beam-splitting prism that directs light to the cornea and the retinal pigment epithelium, where the reflected light creates an interference pattern. A photodetector captures this interference, allowing for precise calculations of the axial length based on the path difference between the two reflective surfaces. Additionally, the same device is capable of measuring the corneal radius through keratometry and the anterior chamber length using slit lamp illumination. These measurements are crucial for ensuring that the selected IOL will provide the best possible refractive outcome for the patient following cataract surgery.