spherical aberration

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Related to Spherical aberrations: Chromatic aberrations

aberration

 [ab″er-a´shun]
1. deviation from the normal or usual.
2. imperfect refraction or focalization of a lens.
chromatic aberration unequal refraction by a lens of light rays of different lengths passing through it, producing a blurred image and a display of colors.
dioptric aberration (spherical aberration) inability of a spherical lens to bring all rays of light to a single focus.
ventricular aberration aberrant ventricular conduction.

spherical aberration

Aberration or distortion of an image due to rays entering the peripheral portion of a spherical mirror or lens being refracted differently from those closer to the center. Thus the peripheral rays are focused on the optical axis at a different point from the central rays.
See also: aberration
References in periodicals archive ?
Szurman, "Influence of the pupil size on visual quality and spherical aberration after implantation of the Tecnis 1piece intraocular lens," British Journal of Ophthalmology, vol.
Caption: Figure 1: Mean values of root mean square (RMS) in [micro]m of total aberrations (Total), lower-order aberrations (LOAs), higher-order aberrations (HOAs), and coma and Spherical aberrations (SAs) for a 4 mm pupil diameter at baseline and one month after orthokeratology wearing.
The magnitude of induced change in coma (-0.180.17) was more than spherical aberrations (0.1320.36).
As the illuminated portion gets bigger, the astigmatism and spherical aberration grow.
[38] indicated that ocular spherical aberration underwent statistically significant diurnal variation, i.e., spherical aberration was positive during the day and gradually became more negative toward the later afternoon/evening.
Conclusions: In overall comparison the mean RMS of total HOAs and spherical aberrations was significantly increased in hypermetropia group and there was a statistically significant negative correlation of SE of hypermetropia with RMS of total HOAs and spherical aberration.
For optical systems with large apertures, such as the eye with a dilated pupil, spherical aberration is a significant problem since the peripheral lens refracts rays of light more than at the centre.
After both the SMILE and FS-LASIK procedures, the changes in spherical aberrations of the anterior surface and the total cornea were positively correlated with the increase in Q value at the anterior corneal surface (all P <0.001), and the changes in spherical aberrations of the posterior surface were negatively correlated with the increase in Q value at the posterior corneal surface (all P <0.001).
Spherical aberrations of intraocular lenses increase as its optical power increases.
This study only analyzed the changes of total higher-order aberrations, total coma aberration, total spherical aberration, and total trefoil aberration corresponding to the RMS value in the children with with-the-rule astigmatism.
The optical design is based on application of positive and negative spherical aberrations in the central part of the lens, in order to increase the depth of focus and to generate a "continuum range of focus." The optic is divided into three different annular zones: the inner and middle zones have different spherical aberrations with opposite signs, whereas the outer one is a monofocal aspherical zone (see Figure 1(b)).
Aspira-aA Horizontal tilt ([degrees]) 0.35 [+ or -] 1.65 Vertical tilt ([degrees]) 0.63 [+ or -] 1.76 Horizontal decentration (mm) 0.03 [+ or -] 0.16 Vertical decentration (mm) 0.08 [+ or -] 0.15 Tecnis ZCB00 Horizontal tilt ([degrees]) 0.67 [+ or -] 1.42 Vertical tilt ([degrees]) 0.19 [+ or -] 1.24 Horizontal decentration (mm) 0.04 [+ or -] 0.27 Vertical decentration (mm) 0.07 [+ or -] 0.23 p value Horizontal tilt ([degrees]) 0.02 Vertical tilt ([degrees]) 0.35 Horizontal decentration (mm) 0.94 Vertical decentration (mm) 0.96 Table 5: Total ocular higher-order spherical aberrations measured at different pupillary diameters in eyes implanted with Aspira or with Tecnis IOL ([micro]m; mean [+ or -] SD; n = 60).