Anterior segment optical coherence tomography in glaucoma

In recent years, the rapid development of diagnostic optic devices has generated optical coherence tomography (OCT) as a new, non-invasive diagnostic method. With technical progress of the infrared spectrum at 1310 nm, OCT of the anterior segment also became feasible. With anterior segment OCT different examinations which so far were ruled out by ultrasound in contact manner could be executed in a non-contact technique: pachymetry, goniometry, illustration of iris and lens configuration as well as postoperative results after different glaucoma surgeries such as trabeculectomy, deep sclerectomy and glaucoma drainage devices. Additionally, anterior segment OCT provides an imaging device for experimental approaches in glaucoma. Today two commercially available units are available: SL OCT (Heidelberg Engineering, Heidelberg, Germany) und Visante (R) OCT (Zeiss Meditec, Jena, Germany). For all applications OCT delivered a high inter- and intraobserver reproducibility, is equal to ultrasound in accuracy and involves a higher patient comfort. Within the different applications, a direct comparison with ultrasound technique reveals minor differences depending on the device type. Therefore, it is advised to indicate the device type with all measurements. OCT enables precise, two-dimensional, non-contact imaging of the anterior segment in high resolution. For glaucomatous diseases, anterior segment OCT enlarges and enriches the armamentarium of glaucoma diagnostics and postoperative care of current modern glaucoma surgery.