Pinhole image comparison with white light source for three different multifocal IOL designs'

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Pinhole image comparison with white light source
for three different multifocal IOL designs.

• Richard Tipperman, M.D.

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Purpose

• To compare pinhole images obtained through a
  modified ISO model eye using a 5 mm aperture and
  a white light source.

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Methods

• 3 medium diopter IOLs were evaluated
• AcrySof ReSTOR SN60D3 (22D4D),
• AMO ReZoomTM NXG1 (20D3.5D) and
• AMO Tecnis Multifocal ZM900 (26.5D4D).
• Images were taken through a Modified ISO model
  eye with a 5mm aperature
• Setup was similar to that for obtaining IOL
  Modulation Transfer Function
• 0.2 micron spherical aberration at 6 mm
  entrance pupil

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Methods

• Headlight simulation was created with following
  compilation on the optical bench
• 50µm pinhole,
• white light.
• Light intensity equivalent to a 2006 Honda
  measured at
• 18o off axis,
• 360 meters.

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Methods
CCD Camera
IOL
Pinhole Target
Light Source
The optical bench setup
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Results
Tecnis Multifocal 26.5D4D
ReZoom 20D3.5D
ReSTOR 20D4D
2 arc min
15 arc min
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Results

• Defocused light around the central focused spot
  was evident in all three IOLs.
• Image quality through the SN60D3 provided the
  sharpest image.
• The size of the spread of the NXG1 and ZM900 IOLs
  was similar and both were larger than the SN60D3.
• More halo and ring patterns were evident with the
  ZM900.

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Discussion

• Schwiegerling, et al found similar results when
  comparing a night driving scene through a 6mm
  pupil.

Schwiegerling J, Choi J, Xe Y, and Ernest P.
(2006, September) Nighttime visual quality with
different multifocal IOLs. Poster presented at
the annual meeting for ESCRS, London.
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Discussion

• Intrinsic to the multifocal IOL design is stray
  light arc caused by misdirection of light to the
  near image.
• Each IOL studied has a different design
• SN60D3 Anterior Surface, Apodized Diffractive
• NXG1 Zonal Refractive
• ZM900 Aspheric, Posterior Surface, Full
  Aperture Diffractive.
• The apodized diffractive steps of the SN60D3 IOL
  gradually apportion more light to the far image
  as pupil size increases effectively limiting
  nighttime arc caused by stray light.

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Conclusion

• Simulating car headlights at nighttime, a
  pinhole image viewed through 3 IOLs demonstrated
  that the apodized diffractive design resulted in
  the best image quality for large pupils at
  nighttime. Clinically, these results suggest the
  ReSTOR lens will produce the least amount of
  visual disturbance.