Oculus Pentacam HR
Oculus Pentacam HR is the gold standard for anterior segment topography and the most advanced device in its series. This German made, high quality unit provides our ophthalmologists with exceptional image quality of the patient’s eye, including the anterior and posterior corneal surfaces, iris, lens, anterior chamber and anterior chamber angle.
Unlike conventional topographers, Pentacam HR measures corneal elevation and does not rely only on curvature values. Because of its outstanding precision, it is of great importance in refractive surgery as well as in the diagnostics of glaucoma and corneal diseases such as keratoconus.
Pentacam HR works on the principle of illuminating the anterior segment of the eye. Different ocular structures reflect and scatter the light beam in different ways, which allows them to be differentiated and visualised. The reflected light is then recorded from multiple angles by two Scheimpflug digital cameras that rotate 360 degrees around the patient’s eye, producing sharp images from the very anterior corneal surface all the way to the posterior surface of the transparent lens.
Illumination principle
Pentacam HR operates on the principle of illuminating the anterior segment of the eye. Different ocular structures reflect or scatter the light beam in different ways, which allows them to be differentiated and visualised. The reflected light is then recorded from several angles by two Scheimpflug digital cameras that rotate 360 degrees around the patient’s eye, producing sharp images from the very anterior surface of the cornea all the way to the posterior surface of the transparent lens.
A second pupil camera tracks eye movements, and the software uses this information to correct the final result so that poor cooperation (blinking, eye movements) does not reduce measurement accuracy. Imaging with this device takes only 2 seconds and there is no contact with the eye, which ensures precise and reliable data. In such a short time Pentacam HR acquires 50 cross sectional images of the cornea consisting of 138,000 individual elevation points.
Detection of subtle changes
In addition to corneal elevation, the device measures the depth and volume of the anterior chamber, chamber angle, pachymetry (corneal thickness), corneal curvature, anterior and posterior corneal topography and the total refractive power of the cornea. At the end of the scan, the ophthalmologist has at their disposal a 3D model of the entire anterior segment, a detailed geometric description and a wide range of high resolution colour maps (up to five times higher resolution than older models).
This allows the ophthalmologist to detect all, even the most subtle opacities of the cornea and lens, both natural and pseudophakic. Previous corneal injuries, pathological changes and performed refractive procedures also become visible in great detail.
The rotating measurement system provides excellent coverage of the corneal surface and reduces the influence of surrounding structures such as the nose or upper orbital rim. Measurement accuracy is +/- 0.1 D (dioptres).
Pentacam HR is also used in the implantation of multifocal toric lenses, where it is very helpful for determining keratometric values to ensure the best possible postoperative vision quality in patients with astigmatism. We also use it in preparation for laser vision correction, a procedure in which a healthy cornea and precise topography measurements are crucial. Corneal topographic mapping is one of the essential examinations before laser dioptre removal can even be considered, so that both the patient and the surgeon can be satisfied with the outcome. Pentacam HR can also be used to assist the ophthalmologist in selecting and fitting contact lenses.
