Imaging the Whole Human Eye

Getting the whole picture of the human eye—from front to retina—has required multiple investigations. Now, researchers at two European universities have combined optical coherence tomography (OCT) with an electrically tunable lens to make a system for imaging the entire eye at once (Optica, doi:10.1364/OPTICA.5.000052).

A new instrument

According to the team led by physicist Ireneusz Grulkowski of Nicolaus Copernicus University (Poland), the new adaptive-focusing, non-invasive instrument can provide more detailed images of ocular structures than other systems and could speed up ophthalmic examinations by eliminating the need for physicians to use separate instruments to see different regions of the eye. Existing medical instruments can focus to a depth of a few millimeters on the front or rear of a patient’s eye.

The scientists, including members of OSA Fellow Pablo Artal’s group at the Universidad de Murcia (Spain), tested the performance of the tunable lens by shining a collimated light beam through it at varying electrical currents. They studied the beam profiles and quantified the aberrations that gravity induces in the tunable lens.

Seeing is believing

For the actual experiments, the researchers incorporated a rapidly tunable swept-source laser, with a central wavelength of 1050 nm, into the system. The light source improves the OCT system’s resolution and depth performance. After testing anterior and retinal imaging separately, the team operated the system at fast switching between the two modes for “quasi-simultaneous” whole-eye imaging. Finally, the scientists used the system to make biometric measurements of the eyes of seven healthy volunteers and compared the data to measurements made with existing clinical ophthalmic instruments.

The new imaging system could also help detect ocular tumors and lead to a better understanding of age-related changes to the interface between the eye’s retina, vitreous gel and crystalline lens.