First Author: C.P SPAIN
Co Author(s): A. Dom L. Belda Salmer T. Ferrer Blasco R. Mont
Purpose:
To evaluate visual and optical quality provided by Implantable Collamer Lenses (ICLs) of different powers (-3, -6 and -15 diopters (D)) and the effect of the small- (< 3.2 mm) and large-incision (3.2 to 4.5 mm) surgery through an adaptive optics system used to simulate vision from the ICLs aberration pattern itself.
Setting:
GIO, Optics Department, Faculty of Physics, Universidad de Valencia, Spain.
Methods:
The irx3 Hartmann-Shack wavefront aberrometer (Imagine Eyes, Orsay, France) together with a custom-made wet-cell was used to obtain the in vitro wavefront of the ICL. In order to simulate the vision of post- ICL implantation surgery in each individual, the crx1 was programmed to compensate the eyes wavefront error using the deformable mirror. Then the aberration pattern of ICLs was induced adding the wavefront pattern of the myopic eye and the HOAs caused by the incision. We analyzed the Modulation Transfer Function (MTF), Point Spread Function (PSF) and the Strehl ratio (SR). High (100%)-, medium (50%)- and low (10%)-contrast visual acuity (VA) was measured using the Freiburg Visual Acuity Test (FrACT) software. The contrast sensitivity (CS) was measured for 3 spatial frequencies: 10, 20 and 25 cycles/degree (cpd). Oriented sinusoidal gratings (0o, 45o, 90o and 135o) were randomly generated and displayed on the micro-display using a 4-alternative, forced-choice method. All measures were taken for 3- and 5-mm pupil.
Results:
Decrease of the optical and visual quality when the incision surgery and ICL power increases due to the increment of aberrations. At 3-mm pupil the effect of a large-incision did not seriously affect VA and CS. No statistically significant differences were found between both incision sizes for any ICL power and spatial frequency evaluated, except for -15D ICL at 25 cpd (p<0.05). Instead, at 5-mm pupil the effect of aberrations with large-incisions became apparent; statistically significant differences in SR, VA and CS were found between both incision sizes for all ICL powers (p<0.05). In all cases optical and visual quality was better with a small-incision. ICL power also affected the optical and visual quality, since we found negative spherical aberration, which was greater when the ICL power was increased. At 3-mm pupil, no statistically significant differences were found in VA and CS between ICL powers, except between -3 and -15D at low-contrast VA and at 20 and 25 cpd of CS (p<0.05). At 5-mm pupil, we did not find statistically significant differences in SR, VA and CS between -3 and -6D ICL, but they did become apparent for -15D ICL for both incision sizes, all contrasts and spatial frequencies(p<0.05).
Conclusions:
The ICL provides good optical and visual quality, although these outcomes decreased with large-incision surgery, since it increases HOAs, especially when the pupil size is greater. Eyes with myopic astigmatism should be preferably implanted with a toric ICL through small incision instead of with the spherical ICL model through a large incision. The optical and visual quality also decreases when the ICL power increases (increase negative spherical aberration), but these losses are offset by the effect of the spectacle magnification. FINANCIAL DISCLOSURE?: No
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