BOOK_CONTENT
From Adaptive Optics for Vision Science

10.3.3   Light Path

The light path in an AOSLO can be thought of as a series of telescopes that
relay the light to the various elements that act on the beam. For example,


FIGURE 10.4 Schematic of an adaptive optics scanning laser ophthalmoscope. The optical path is described in the text. The specific labeled elements are: CL, collimating lens; AOM, acousto-optic modulator; EP, entrance pupil; BS, beamsplitter; DM, deformable mirror; HS, horizontal scanning mirror; VS, vertical scanning mirror; PT, pupil tracking mirror; LA, lenslet array; CP, confocal pinhole; PMT, photomultiplier tube. Pupil conjugates and retinal conjugates are labeled p and r, respectively. Mirrors and lenses are labeled M# and L# though the optical path. Telescope lens/mirror pairs for relaying the pupil through the path are L1–L2, L3–L4, M1–M2, M3–M4, M5–M6, M7–M8.


wavefront sensing (p6 in Fig. 10.4), wavefront correcting (p3), and tip and tilt
adjustments (p1 and p2) for raster scanning the beam all need to be done in
a pupil-conjugate plane. At present, each of these actions is done with a separate
component, and hence, a telescope is required to relay conjugate images
of the pupil to the various components. So the AOSLO is comprised of five
different telescopes that relay the light to six different pupil-conjugate positions
(aside from the actual pupil). To consider the optical path in this way
makes calculations of the magnification of the system simple since the relative
magnification between any two pupil-conjugate planes is the product of the
magnification of the telescopes that lie between them. Likewise, the retinal-
conjugate paths are connected by a series of telescopes made up of the same
mirror lenses.

Maintaining conjugacy is critical in an AOSLO. If, for example, the pupil
is not conjugate to the scanning...


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Topics of Interest

10.3.4   Light Delivery It is important to start with a point source or a well-collimated beam in order to focus a beam onto the retina. The light source in an SLO generally originates from a...

10.2.3   Optical Components As shown in the schematic, the deformable mirror and lenslet array of the wavefront sensor are strategically positioned conjugate to the eye’s pupil. There are...

10.3.6   Raster Scanning Two mirrors are generally used to scan the focused spot in a raster pattern on the retina. One mirror scans the line, defining the line rate, and the other scans...

18.1   INTRODUCTION Conventional phoropters are used by ophthalmologists and optometrists to estimate and correct for the lower order aberrations of the eye, defocus and astigmatism, in order to...

10.5.3   Refraction To relieve the demand on the deformable mirror, it is important to correct for as much of the refractive error of the patient prior to AO correction. The defocus of the eye...