Page 248 - Optofluidics Fundamentals, Devices, and Applications

Bio-Inspir ed Fluidic Lenses for Imaging and Integrated Optics 223

CMOS sensor

Pupil &
IR filter
Mirror

Carneal Fluidic
lens IOL

Water

FIGURE 9-18 Schematic of experimental pseudoaphakic eye with a plano-
convex fl uidic IOL. (W. Qiao, F. Tsai, S. H. Cho, and Y.-H. Lo, “Fluidic
intraocular lens with a large accommodation range,” IEEE Photonic
Technology Letters, copyright (year) IEEE.)

CMOS sensor is displayed on the computer screen and digitally
recorded for visualization and further analysis. Behind the plano-
convex corneal lens is a biconvex lens, which is later on replaced with
the fluidic lens to evaluate the image quality and range of accommoda-
tion. A 5-mm-diameter pupil and an infrared filter are inserted between
the cornea and the lens. The experimental eye model is filled with
water. A 45-mirror deflects the light path toward the CMOS image sen-
sor, which is placed right above water to acquire data at the equivalent
position of the fovea. The dimension of the pixel is 3.18 μm. The near
point of the experimental eye model is defined to be 45 cm. At this
distance, the eye model shows a resolution of 0.07 mm, corresponding
to the same resolution as the near point of 25 cm for emmetropia eye
with normal visual acuity (i.e., one arc minute). After finishing the opti-
cal quality evaluation of the eye model, the fixed biconvex lens is
replaced with a plano-convex fluidic IOL. When changing the curva-
ture of the fluidic IOL, a well-focused image can be formed from one
half of the near distance (22.5 cm) to infinity. Since one half of the near
point in the experiment is equivalent to 12.5 cm for emmetropia eye,
the experimental eye model can achieve a subject accommodation
range of 8 D. Taking pseudo-accommodation (i.e., accommodation
caused by the influence of depth of field) into consideration, the real
tuning range of effective focal length is a bit smaller than subjective
accommodation range.
Figures 9-19 and 9-20 are taken with the aforementioned pseu-
doaphakic eye model using a plano-convex fluidic IOL. Figure 9-19a