Tilt and Decentration of Intraocular Lenses-a Brief Review

Abstract

Eyes need a flexible, clear and refractively suited lens to provide the retina with sharp images in far and near distance. But even given an optimal lens, the resulting image would be blurred without proper lens positioning, observable in some cases of Marfan syndrome or after ocular trauma with lens dislocation. In contrast, as seen in routine ophthalmologic slit lamp examination, healthy eyes do not suffer from coarse lens misalignment.

Binocular System with Asymmetric Eyes

“…Although, the asymmetry parameters of the refractive surface are defined relative to the optical axis, the assumed values of the tilt given by angle β and the calculated decentration e are of the order of the corresponding values reported in [20,21]. Moreover, the calculated range in (15) agrees with the observed values of the abathic distance in human vision [23,24], its average value being…”

Binocular System with Asymmetric Eyes

“…Although, the asymmetry parameters of the refractive surface are defined relative to the optical axis, the assumed values of the tilt given by angle β and the calculated decentration e are of the order of the corresponding values reported in [20,21]. Moreover, the calculated range in (15) agrees with the observed values of the abathic distance in human vision [23,24], its average value being…”

Binocular system with asymmetric eyes

“…Although, the asymmetry parameters of the refractive surface are defined relative to the optical axis, the assumed values of the tilt given by angle β and the calculated decentration e are of the order of the corresponding values reported in [20,21]. Moreover, the calculated range in (15) agrees with the observed values of the abathic distance in human vision [23,24], its average value being…”

“…The last model, the asymmetric eye, is shown in Figure 4 (b). This is the simplest extension of the reduced eye that includes the foveal displacement from the posterior pole and the cornea and the crystalline lens's misalignments normally present in human eyes [20,21]. The longitudinal horopter curves in the binocular system with asymmetric eyes are found, in this paper, to resemble empirical horopters.…”

Intraoperative trypan blue central landmark and its use in capsulotomy and capsulorhexis centration

“…Furthermore, symmetrical coverage within the IOL decentration tolerance of 0.3 mm is achieved in 100% of capsulotomies centered on the TC landmark (Group 2) and the CPR (Group 3) providing the theoretical optimal optical performance. 11,12 The TC landmark was statistically equivalent to the centration accuracy of centering on the CPR.…”

“…[3][4][5][6][7][8][9][10] IOL centration on the visual axis is critical for IOL performance where a decentration of more than 0.3 mm degrades the optical performance. 11,12 For traditional IOLs with haptics in the capsular bag equator, the capsulotomy does not affect the IOL position immediately, but asymmetric capsulotomy may affect tilt and centration by asymmetric forces on the IOL during postoperative healing. For capsulotomy rim-fixated IOLs, the capsulotomy defines the IOL position, and hence, centration on the visual axis is more critical.…”

Binocular System with Asymmetric Eyes

“…Although, the asymmetry parameters of the refractive surface are defined relative to the optical axis, the assumed values of the tilt given by angle β and the calculated decentration e are of the order of the corresponding values reported in [20,21]. Moreover, the calculated range in (15) agrees with the observed values of the abathic distance in human vision [23,24], its average value being…”

Binocular system with asymmetric eyes

“…Although, the asymmetry parameters of the refractive surface are defined relative to the optical axis, the assumed values of the tilt given by angle β and the calculated decentration e are of the order of the corresponding values reported in [20,21]. Moreover, the calculated range in (15) agrees with the observed values of the abathic distance in human vision [23,24], its average value being…”

“…The last model, the asymmetric eye, is shown in Figure 4 (b). This is the simplest extension of the reduced eye that includes the foveal displacement from the posterior pole and the cornea and the crystalline lens's misalignments normally present in human eyes [20,21]. The longitudinal horopter curves in the binocular system with asymmetric eyes are found, in this paper, to resemble empirical horopters.…”

Intraoperative trypan blue central landmark and its use in capsulotomy and capsulorhexis centration

“…Furthermore, symmetrical coverage within the IOL decentration tolerance of 0.3 mm is achieved in 100% of capsulotomies centered on the TC landmark (Group 2) and the CPR (Group 3) providing the theoretical optimal optical performance. 11,12 The TC landmark was statistically equivalent to the centration accuracy of centering on the CPR.…”

“…[3][4][5][6][7][8][9][10] IOL centration on the visual axis is critical for IOL performance where a decentration of more than 0.3 mm degrades the optical performance. 11,12 For traditional IOLs with haptics in the capsular bag equator, the capsulotomy does not affect the IOL position immediately, but asymmetric capsulotomy may affect tilt and centration by asymmetric forces on the IOL during postoperative healing. For capsulotomy rim-fixated IOLs, the capsulotomy defines the IOL position, and hence, centration on the visual axis is more critical.…”

Binocular System with Asymmetric Eyes

“…Although, the asymmetry parameters of the refractive surface are defined relative to the optical axis, the assumed values of the tilt given by angle β and the calculated decentration e are of the order of the corresponding values reported in [20,21]. Moreover, the calculated range in (15) agrees with the observed values of the abathic distance in human vision [23,24], its average value being…”

Binocular system with asymmetric eyes

“…Although, the asymmetry parameters of the refractive surface are defined relative to the optical axis, the assumed values of the tilt given by angle β and the calculated decentration e are of the order of the corresponding values reported in [20,21]. Moreover, the calculated range in (15) agrees with the observed values of the abathic distance in human vision [23,24], its average value being…”

“…The last model, the asymmetric eye, is shown in Figure 4 (b). This is the simplest extension of the reduced eye that includes the foveal displacement from the posterior pole and the cornea and the crystalline lens's misalignments normally present in human eyes [20,21]. The longitudinal horopter curves in the binocular system with asymmetric eyes are found, in this paper, to resemble empirical horopters.…”

Intraoperative trypan blue central landmark and its use in capsulotomy and capsulorhexis centration

“…Furthermore, symmetrical coverage within the IOL decentration tolerance of 0.3 mm is achieved in 100% of capsulotomies centered on the TC landmark (Group 2) and the CPR (Group 3) providing the theoretical optimal optical performance. 11,12 The TC landmark was statistically equivalent to the centration accuracy of centering on the CPR.…”

“…[3][4][5][6][7][8][9][10] IOL centration on the visual axis is critical for IOL performance where a decentration of more than 0.3 mm degrades the optical performance. 11,12 For traditional IOLs with haptics in the capsular bag equator, the capsulotomy does not affect the IOL position immediately, but asymmetric capsulotomy may affect tilt and centration by asymmetric forces on the IOL during postoperative healing. For capsulotomy rim-fixated IOLs, the capsulotomy defines the IOL position, and hence, centration on the visual axis is more critical.…”