Sclervey allows for precision lens fitting after a single appointment, due to its astonishingly precise measurement of the eye's shape. The device uses its array of seven ICX424 CCDs to image every portion of the eye with at least three cameras simultaneously, each capturing 550 pixels per millimeter, allowing Sclervey to move beyond the realm of fit (tolerance of 50 μm) to the realm of comfort, with a standard deviation of measurement of 17 μm.
Sclervey makes scleral lens fitting a data-driven process by providing a single 3D image of the entire sclera. The device takes four images of the eye: looking forward, right, down-left, and up-left, guided by an alignment light. These four partial 3D maps are then stitched together with software to yield a single 3D image, with a 21 mm arc diameter, sufficient for fitting all common custom scleral lenses with no guesswork.
The thirteen printed circuit boards (PCBs) containing the CCD cameras (blue) and LED arrays (red) of Sclervey as well as the thirteen lenses that focus them are held together by a block, machined out of a single brick of material by a 5-axis milling machine to 5 μm. This precision allows the lenses and PCBs to be positioned accurately and focus cleanly on the eye's surface with minimal calibration.
Sclervey operates by combining the images taken from different cameras, analyzing their overlap, and using stereo-geometry to construct a 3D model. However, only two cameras are necessary to find the 3D position of the eye by this method. By having every point visible to at least three cameras, Sclervey has enough information to improve its data about the precise locations of its cameras and lenses, allowing the device to become more accurate with every patient.
By projecting dots from embedded LEDs rather than lines or other continuous images, and by using a mass-produced camera CCD chip, Sclervey is able to keep the cost of its electrical components to a minimum, without any compromise in precision or reliability.