Future developments - Adaptive Optics Applied to Glaucoma Imaging

Scanning laser ophthalmoscopy (SLO) and optical coherence tomography (OCT) have substantially advanced ophthalmic imaging by improving the transversal resolution and axial resolution beyond that which can be achieved by the fundus camera. SLO improved the transversal resolution by using a small aperture in front of the photodetector and OCT improved the axial resolution by employing principles of coherence gating. Combining the two technologies into a single instrument produces an OCT instrument with the transversal resolution of an SLO but the finer axial resolution afforded by OCT principles, typically 5-10 um or less. Transversal resolution of both SLO and OCT instruments is limited by the aberrations of the eye to more than 15 um with a pupil size of less than 3 mm. Transversal resolution in both instruments can, in principle, be improved to less than 3 um resolution by enlarging the beam diameter. In practice, this often fails due to imperfections in the crystalline lens, cornea, intraocular fluid, and tear film that disturb the wavefront, and hence distort the round uniformity of the spot illuminating the retina. Applying adaptive optics (AO) principles, aberrations of the eye can be both measured and compensated