Decentration of 5.1 mm intraocular lenses after continuous curvilinear capsulorhexis and in-the-bag fixation

Visual and optical performance of the Akreos Adapt Advanced Optics and Tecnis Z9000 intraocular lenses: Swedish multicenter study

PURPOSE

To compare the subjective visual and objective optical performance of 2 aspherical intraocular lenses (IOLs), the Akreos Adapt Advanced Optics (AO) (Bausch & Lomb, Inc.) and the Tecnis Z9000 (Advanced Medical Optics, Inc.).

SETTING

Four university hospitals in Sweden.

METHODS

This study comprised 80 patients, 20 each from 4 university hospital centers in Sweden. All patients had bilateral clear corneal phacoemulsification with implantation of an Akreos Adapt AO IOL in 1 eye and Tecnis Z9000 IOL in the other eye according to a randomization protocol. Preoperatively, 90% contrast Early Treatment Diabetic Retinopathy Study (ETDRS) visual acuity was measured and the mesopic pupil sizes were determined. Ten to 12 weeks postoperatively, 12.5% and 90% contrast ETDRS visual acuities and photopic and mesopic Functional Acuity Contrast Test chart contrast sensitivities were determined. Wavefront analysis was performed with the Zywave II aberrometer (Bausch & Lomb, Inc.), and a questionnaire on the subjective quality of vision was completed by each patient.

RESULTS

The Akreos AO IOL and Tecnis Z9000 IOL produced similar high- and low-contrast visual acuities as well as photopic and mesopic contrast sensitivities. The Tecnis Z9000 IOL resulted in lower spherical aberrations of the eye (mean 0.05 +/- 0.13 microm versus 0.35 +/- 0.13 microm root mean square, 6.0 mm pupil) (P<.001); however, the Akreos AO IOL provided a larger depth of field (mean 1.22 diopter [D] +/- 0.48 [SD] versus 0.86 +/- 0.50 D, 6.0 mm pupil) (P<.001). Patient satisfaction was generally high, although 68.8% of the patients reported some type of visual disturbance postoperatively. Twenty-eight percent of patients reported better subjective visual quality in the Akreos AO eye and 14%, in the Tecnis Z9000 eye (P<.0001). Accordingly, 33% perceived more visual disturbances in the Tecnis Z9000 eye and 11%, in the Akreos AO eye (P<.0001).

CONCLUSIONS

Maximum reduction of spherical aberration did not maximize subjective visual quality. The higher perceived quality of vision with the Akreos AO IOL could be because of differences in depth of field, IOL material, or IOL design.

Update on fixation of rigid and foldable posterior chamber intraocular lenses. Part I: Elimination of fixation-induced decentration to achieve precise optical correction and visual rehabilitation

PURPOSE

Realizing that precise posterior chamber intraocular lens (PC-IOL) centration is needed to consistently achieve good optical results and visual rehabilitation after modern cataract surgery, the authors assessed the status and success rate of lens haptic fixation and its correlation with lens optic centration-decentration in a large series of eyes with PC-IOLs obtained postmortem.

DESIGN

Prospective analysis of pseudophakic eyes obtained postmortem.

PARTICIPANTS

A total of 3493 human eyes obtained postmortem, the largest database of such specimens available to date.

METHODS

Miyake-Apple posterior photographic technique.

MAIN OUTCOME MEASURES

The amount of decentration of rigid PC-IOLs and small-incision foldable PC-IOLs was analyzed, and the results were correlated with the type of fixation that had been achieved in each case.

RESULTS

Determination of mean values revealed that capsular bag fixation was achieved in 52.05% of eyes, asymmetric bag-sulcus fixation in 34.21 % of eyes, and sulcus-sulcus fixation in 13.74% of eyes. Asymmetrically fixed lenses consistently showed significant decentration. During the past 5 years (1993-98), the overall rate of in-the-bag fixation increased to 59.2%; by 1998 it had increased to 64%. Most significantly, success in achieving bag-bag fixation of foldable IOLs implanted in association with modern capsular surgery with small incisions has surged to 90% over the past 4 years.

CONCLUSIONS

The authors found a direct correlation of decentration in eyes with asymmetric fixation, and the results underscore the need for careful in-the-bag haptic placement. Although few surgeons today would dispute the goal to implanting haptics in the capsular bag, these findings show that the overall success rate over the years has, while improving, remained surprisingly low. The overall success rate of about 60% seen with all lens designs is probably as good as can be expected with classic large-incision extracapsular techniques. However, and most important and encouraging, the success rate of haptic fixation in cases with foldable lenses has improved dramatically during the past 4 years (up to the 90% range). This coincides with the present emphasis on modern capsular surgery and small-incision techniques used to insert these lenses.