Multifocal intraocular lens implantation in patients with traumatic cataract

Full-Diffractive Multifocal Intraocular Lens Posterior Optic Capture for Selected Pediatric Cataracts

PURPOSE

To evaluate the short-term outcomes of implantation of a full-diffractive multifocal intraocular lens (IOL) with optic capture for selected pediatric cataracts.

METHODS

In this prospective study, patients with pediatric cataract aged 3 to 14 years were selected to receive multifocal IOL (Tecnis ZMB00; Abbott Medical Optics) posterior optic capture. Visual acuity, stereopsis, visual quality, and complications were assessed.

RESULTS

Forty-five patients (66 eyes) were recruited with a follow-up of 9.09 ± 5.93 months (range: 6 to 24 months). The cataract was bilateral in 21 patients and unilateral in 24 patients. At the last follow-up visit, the mean distance-corrected distance, intermediate, and near visual acuity was 0.28 ± 0.25, 0.43 ± 0.24, and 0.39 ± 0.27 logMAR, respectively. Among the patients with bilateral cataract, postoperative corrected distance visual acuity (CDVA) was 20/40 or better in 79% (33 of 42) of the eyes and 20/20 in 26% (11 of 42) of the eyes. Of the patients with unilateral cataract, 54% (13 of 24) achieved a CDVA of 20/40 or better but none obtained a CDVA of 20/20. All patients developed stereopsis postoperatively (P < .05). There was no significant difference in modulation transfer function cut-off and Strehl ratio between the eyes with a multifocal IOL and the healthy eyes of patients with unilateral cataract (P > .05). Objective Scatter Index values were significantly better in the healthy eyes (P < .05). No posterior capsule opacification, posterior synechiae, secondary glaucoma, pigmentary IOL deposits, or IOL decentration was observed during the follow-up period.

CONCLUSIONS

Short-term follow-up results suggest full-diffractive multifocal IOL optic capture may benefit appropriately selected patients with pediatric cataract. [J Refract Surg. 2021:37(6):390-397.].

Presbyopia: Effectiveness of correction strategies

Presbyopia is a global problem affecting over a billion people worldwide. The prevalence of unmanaged presbyopia is as high as 50% of those over 50 years of age in developing world populations, due to a lack of awareness and accessibility to affordable treatment, and is even as high as 34% in developed countries. Definitions of presbyopia are inconsistent and varied, so we propose a redefinition that states "presbyopia occurs when the physiologically normal age-related reduction in the eye's focusing range reaches a point, when optimally corrected for distance vision, that the clarity of vision at near is insufficient to satisfy an individual's requirements". Strategies for correcting presbyopia include separate optical devices located in front of the visual system (reading glasses) or a change in the direction of gaze to view through optical zones of different optical powers (bifocal, trifocal or progressive addition spectacle lenses), monovision (with contact lenses, intraocular lenses, laser refractive surgery and corneal collagen shrinkage), simultaneous images (with contact lenses, intraocular lenses and corneal inlays), pinhole depth of focus expansion (with intraocular lenses, corneal inlays and pharmaceuticals), crystalline lens softening (with lasers or pharmaceuticals) or restored dynamics (with 'accommodating' intraocular lenses, scleral expansion techniques and ciliary muscle electrostimulation); these strategies may be applied differently to the two eyes to optimise the range of clear focus for an individual's task requirements and minimise adverse visual effects. However, none fully overcome presbyopia in all patients. While the restoration of natural accommodation or an equivalent remains elusive, guidance is given on presbyopic correction evaluation techniques.

Extended focal length intraocular lens implantation in posttraumatic posterior capsular rupture

We present a case of posterior capsular defect with traumatic cataract after blunt trauma in which an extended focal length intraocular lens (IOL) was implanted in the bag after conventional phacoemulsification and anterior vitrectomy. Anterior segment optical coherence tomography performed preoperatively aided in the confirmation and documentation of the capsular integrity. Intraoperative trocar anterior chamber (AC) maintainer allowed AC maintenance without further complications. IOL was well centered postoperatively at 6 months, and the unaided visual acuity was 20/20 for distance and N8 for near. The report showed that an extended depth of focus IOL can be placed in eyes with ruptured posterior capsule for good visual outcome in posttraumatic young eyes and it may not be considered as a relative contraindication for it.

Assessment of dysphotopsia in pseudophakic subjects with multifocal intraocular lenses

Aim

To better understand the phenomenon of dysphotopsia in patients implanted with multifocal intraocular lenses (IOLs).

Methods

Forty-five patients (aged 61.8±8.9 years) implanted bilaterally with Tecnis ZM900 (diffractive multifocal), Lentis Mplus MF30 (segmented refractive multifocal) or Softec-1 (monofocal) IOLs (each n=15) 4-6 months previously and who had achieved a good surgical outcome were examined. Each reported their dysphotopsia symptoms subjectively, identified its form (EyeVisPod illustrations), quantified retinal straylight (C-Quant) and halo perception (Aston halometer). Retinal straylight and halometry was repeated by a second masked clinician to determine interobserver repeatability.

Results

Subjective dysphotopsia ratings were able to differentiate Tecnis ZM900 from Lentis Mplus MF30 (p<0.001), but not Lentis Mplus MF30 from groups implanted with Softec-1 (p=0.290). Straylight was similar between the monofocal and multifocal IOL designs (p=0.664). ZM900 IOLs demonstrated a uniform increase in dysphotopsia in comparison with the monofocal IOL (p<0.001) as measured with the halometer, whereas sectorial refractive multifocal IOLs demonstrated a localised increase in dysphotopsia over the inferior visual field. Intraobserver repeatability was good for the straylight (intraclass correlation coefficients (ICC)=0.77) and halometry (ICC=0.89). There was no significant correlation between the subjective dysphotopsia severity and the straylight (p=0.503) or halometry (p>0.10) quantification or between straylight and the halo area (p>0.30).

Conclusions

Multifocal IOLs induce symptoms of dysphotopsia. Straylight did not differentiate between IOL designs, however halometry identified clear differences in light scatter due to the IOL optics. Whereas, subjective rating of overall dysphotopsia are not strongly associated with straylight or halo perception, the halometry polar diagram reflected the subjective descriptions of dysphotopsia.

[Optical performance of multifocal intraocular lenses. Investigation of the Array SA40N vs. Acri. Twin at the "physical eye" according to Reiner and Jacobi]

BACKGROUND

Reduced contrast sensitivity, glare disability and insufficient bifocality are the main drawbacks of multifocal intraocular lenses (IOL). The bilateral implantation of diffractive IOL with an asymmetrical light distribution for distance and near focus is an alternative concept that aims to improve the contrast sensitivity and bifocality of conventional multifocal IOL.

PATIENTS AND METHODS

The optical performance of monofocal (PhacoFlexII SI40) and multifocal IOL (Array SA40N; Acri. Twin 737D/733D) was quantitatively assessed in 18 healthy probands and qualitatively determined by digital photographic recording using an optical apparatus, the "physical eye", according to Reiner and Jacobi. Vision examination included standard tests of distance and near visual acuity, contrast sensitivity and low contrast visual acuity testing under varying pupil size using a video acuity tester.

RESULTS

Distance visual acuity was significantly superior with the SI40 and distant-dominant 737D compared to the SA40N and near-dominant 733D. At near, the 733D had the best performance. Contrast sensitivity was better with the 737D than the SA40N when both were compared with the SI40. No normal contrast sensitivity could be determined with the 733D because of the optical phenomenon of 'spurious resolution'. Variation in pupil size had less impact on contrast acuity with the Acri. Twin IOL compared to the SI40 and SA40N. Photographic testing revealed better edge contrast with the Acri. Twin than the SA40N.

CONCLUSIONS

The optical performance of multifocal IOL correlates with the properties of physical light distribution. Differences in edge contrast may be discerned using photographic recording.

Multifocal intraocular lenses

PURPOSE OF REVIEW

Multifocal intraocular lenses (IOLs) are growing in popularity among patients and surgeons, and opened the way to refractive lens exchange. Still they are not used routinely in cataract surgery, for reasons probably connected to the frequently observed reduction in contrast sensitivity. Recent papers with clinical study outcomes can help in understanding the advantages and the limits of multifocal IOLs.

RECENT FINDINGS

Emerging from every published study, both refractive and diffractive multifocal IOLs usually provide good near visual acuity with distance correction. As many multifocal IOLs are distance-dominant, near vision can be improved by correcting for near the distance focus. The near contrast sensitivity thus obtained is similar to that of monofocal IOLs. Multifocal IOLs have been employed with success in complicated cataract surgery and in trauma cases, with the same outcome as in normal cataract cases. Presbyopic lens exchange remains controversial, with a high success rate in original ametropic eyes, but limited success in original emmetropic eyes. Secondary procedures to improve the refractive outcome are usually of little efficacy in improving patient satisfaction. A new anterior chamber phakic multifocal IOL has been designed to correct presbyopia and small refractive errors. The first clinical results indicate high patient satisfaction, with 7.3% explantation rate.

SUMMARY

Multifocal IOLs can be more widely used after cataract surgery, but should be used with caution in almost emmetropic eyes with little or no cataract. Refractive lens exchange with multifocal IOL is especially worthwhile in hyperopic eyes. The new phakic multifocal IOL adds the concept of reversibility to presbyopic lens exchange.