Functional vision after cataract removal with multifocal and accommodating intraocular lens implantation

Visual Acuity and Contrast Sensitivity Function after Accommodative and Multifocal Intraocular Lens Implantation

Purpose

To evaluate visual acuities and contrast sensitivities (CS) after accommodative, refractive, and diffractive multifocal intraocular lens (IOL) implantations.

Methods

After cataract extractions, in 20 eyes accommodative IOL (group 1), in 30 eyes refractive IOL (group 2), and in 20 eyes diffractive multifocal IOL (group 3) implantations were performed. CS were measured with the stereo optical functional acuity contrast test. Uncorrected distance (UCDVA) and distance corrected near visual acuities (DCNVA) and refractive values were determined.

Results

The mean UCDVA (0.99±0.03) and DCNVA (0.98±0.04) of group 3 were significantly better than the other IOL groups. The mean DCNVA of group 2 (0.71±0.14) was significantly better than group 1 (0.5±0.08). One month after the operations CS, values of group 2 were significantly lower than the 2 other IOL groups. Photopic CS values of group 1 at 12 and 18 cycles per degree (cpd) were significantly higher than group 3. Three months after the operations, CS values of group 1 and 3 were significantly higher than that of group 2 at 3, 6, 12, and 18 cpd and in all spatial frequencies respectively. There was no difference between groups 1 and 3 with respect to photopic CS values. Mesopic CS values of group 3 were significantly higher than that of group 1 at 1.5, 3, and 6 cpd. At the 6th and 12th month, CS values of group 3 were similar or better compared to the values of the 3rd month.

Conclusions

The diffractive multifocal IOL resulted in more favorable visual acuities and higher CS values than accommodative and refractive multifocal IOL.

Accommodative Intraocular Lenses: Short-Term Visual Results of Two Different Lens Types

Purpose

To compare the ability of two types of accommodative intraocular lenses (IOLs) to provide uncorrected near and distance visual acuity (VA) after cataract surgery.

Methods

A total of 108 eyes of 75 patients underwent cataract surgery by phacoemulsification and IOL implantation either bilaterally or monocularly with one of two types of accommodative IOLs: the AT-45 lens (69 eyes) or the 1-CU lens (39 eyes). Patients were followed for up to 1 year after cataract surgery. Near VA was measured through the distance correction to obtain the true near vision effect of the accommodating IOL.

Results

Uncorrected distance VA of 20/30 or better was achieved by 84.6% of the bilaterally implanted 1-CU patients and 73.6% of the bilaterally implanted AT-45 IOL patients 1 year following surgery. Uncorrected near VA of J1 or better was achieved by 42% of the patients with the bilateral 1-CU implant and 36.8% of the patients with the bilateral AT-45 implant. For J3 or better near acuity, the values were 92.3% for the bilateral 1-CU patients and 84.2% for the bilateral AT-45 patients at 1 year. A total of 54% of the eyes with 1-CU implants underwent a mild myopic shift (<1.0 D), 21% had a mild hyperopic shift, and 45% of the eyes were emmetropic at 1 year.

Conclusions

Both accommodative IOLs provided good near and distance vision postoperatively. The 1-CU IOL appears clinically to provide slightly better uncorrected distance and distance-corrected near VA than the AT-45 lens.

Diffractive multifocal intraocular lens compared to pseudo-accommodative intraocular lens implant for unilateral cataracts in pre-presbyopic patients

Purpose:

To evaluate the efficacy of diffractive multifocal and pseudo-accommodative IOLs in pre-presbyopes with cataract.

Materials and Methods:

A prospective randomized control study was performed on patients with cataract in the pre-presbyopic age group. Patients were randomly allocated to 2 groups: Group 1 comprised 12 patients who underwent implantation of a diffractive multifocal IOL and Group 2 comprised 13 patients who underwent implantation of a pseudo-accommodative IOL after standard phacoemulsification. Efficacy was measured by postoperative distance and near uncorrected visual acuity, contrast sensitivity, spectacle independence, and glare and halo.

Results:

The study patients were aged 22–35 years and included 14 females and 11 males. All examinations were performed 6 months postoperatively by a second observer unaware of the study objectives. Mean uncorrected distance visual acuity was 0.125 ± 0.1 LogMAR in Group 1 and 0.1385 ± 0.1 in Group 2 (P = 0.7993). Near visual acuity was 0.0917 ± 0.1 in Group 1 and 0.386 ± 0.2 in Group 2 (P < 0.0001). Contrast sensitivity was good in both groups based on the Pelli-Robson chart (P = 0.3919). Night-time glare was present in 3 (25%) patients in Group 1 and in 2 (15.4%) patients in Group 2. No patients in either group had difficulty driving during the day or night. Ten patients in Group 1 (83.3%) and 7 patients in Group 2 (53.85%) had spectacle independence (P = 0.1249).

Conclusion:

Greater proportions of patients who underwent diffractive multifocal implantation achieved functional distance and near vision as compared to those in the pseudo-accommodative IOL group. There was greater variability in near vision in patients who received the pseudo-accommodative IOL as compared to those in the multifocal IOLs. Contrast sensitivity remained adequate in both the groups. There were more glare and halos in the multifocal group as compared to those in the pseudo-accommodative group. More patients achieved spectacle independence with multifocal IOLs.

Paraxial analysis of the depth of field of a pseudophakic eye with accommodating intraocular lens

PURPOSE

To investigate the depth of field of pseudophakic eye implanted with translating optics accommodating intraocular lenses (AIOLs).

METHODS

Theoretical analyses using paraxial optics equations were used. The crystalline lens in the Navarro eye model was replaced with an AIOL modeled as a thin-lens system with either a single lens element (1E-AIOL) or two element (2E-AIOL). To quantify the depth of field, a reference limit for retinal blur circle diameter was adopted from typical values of depth of field of the normal eye. Effect of various factors including AIOL type, lens element power, implant position, and pseudophakic accommodation on depth of field were analyzed.

RESULTS

Depth of field increased with more posterior positioning of the AIOL and decreased with pseudophakic accommodation by translation of optics. However, the changes did not exceed 0.02 D over the range of factors tested. Effective depth of field, defined as the magnification adjusted depth of field, is relatively independent of the implant position and power combination of AIOL. Effects of varying design factors on the depth of field of AIOL are too small to be clinically observable.

CONCLUSIONS

Although depth of field extends the range of near vision with AIOL, varying design and surgical factors such as depth of implantation and optical power of lens element(s) within clinically practical limits modifies depth of field by an insignificant amount. In the practical sense, attempting to enhance the depth of field of AIOL by varying design factors such as the position of implantation would be unrewarding.

Biconvex posterior chamber accommodating intraocular lens implantation after cataract surgery: long-term outcomes

PURPOSE

To evaluate the long-term efficacy of a biconvex accommodating intraocular lens (IOL) to restore near visual performance.

SETTING

Department of Ophthalmology, Keio University Hospital, Tokyo, Japan.

METHODS

This 4-year study comprised eyes that had cataract surgery with implantation of a 1CU accommodating IOL. At all postoperative visits, the following were assessed: subjective spherical equivalent (SE) refraction; uncorrected (UDVA) and corrected (CDVA) distance visual acuities; uncorrected (UNVA), distance-corrected (DCNVA), and corrected (CNVA) near visual acuities; change in minimum additional (add) power (diopters) to attain CNVA; and accommodation amplitude. A questionnaire was administered at the last visit.

RESULTS

Twelve eyes of 8 cataract patients (mean age 59.0 years +/- 18.4 [SD]) were evaluated. Postoperatively, the mean SE at 1 year and 4 years was significantly more hyperopic than at 1 month (P<.05). The mean UDVA increased significantly at 4 years compared with 1 month (P<.05). There were no significant changes in CDVA, UNVA, CNVA, and DCNVA throughout the follow-up period. The change in the minimum add power to attain CNVA and in the subjective and objective accommodation amplitudes also did not change significantly over time. Eighty-three percent of patients reported being satisfied with the results.

CONCLUSION

Four years after implantation of an accommodating IOL, most patients had good vision and were satisfied, although the accommodation amplitude for near vision was not sufficient throughout the follow-up.

Objective accommodation measurements in prepresbyopic eyes using an autorefractor and an aberrometer

PURPOSE

To test the repeatability of the iTrace wavefront aberrometer (Tracey Technologies, Inc.) and the WR-5100K autorefractor (Grand Seiko Co., Ltd.) and to measure accomodation in young and phakic prepresbyopic subjects.

SETTING

University of Houston, College of Optometry, Houston, Texas, USA.

METHODS

This study comprised 30 young adults and 15 prepresbyopic subjects. Accommodation was stimulated with near charts presented at various distances. Measurements were repeated 3 times for each target distance with both instruments. For test-retest reliability, the entire protocol was repeated on 3 additional days in 3 prepresbyopic subjects as well as twice on the same day in the young adults.

RESULTS

The mean age was 25.5 years +/- 3.25 (SD) (range 21 to 31 years old) in the young adult group and 41.2 +/- 2.98 years (range 38 to 49 years) in the prepresbyopic group. Bland-Altman analysis of repeated measures of the young subjects had limits of agreements (LoA) of 1.58 diopters (D) or less for each instrument and when compared between instruments. Normalized mean stimulus response functions in the prepresbyopic group were similar for the 2 instruments. Bland-Altman analysis of the accommodation measurements between the 2 instruments showed a mean difference of 0.07 D and an LoA of 0.70 D. Repeated measures of 3 prepresbyopic subjects had a range of standard deviations from 0.07 to 0.51 D.

CONCLUSION

The accommodative responses measured with the 2 instruments were not significantly different, and testing showed both instruments to be suitable for objective measurement of accommodation in a phakic prepresbyopic population with low accommodative amplitudes.

Refractive lens exchange for presbyopia

True presbyopia correction still remains one of the main challenges amongst eye professionals. Many corrective techniques exist including bifocal spectacle correction, monovision techniques both with corrective lenses and surgery, multifocal corneal excimer laser and refractive lens exchange with either accommodating or multifocal lenses. Refractive lens exchange was first described more than 10 years ago and has become more accepted in recent years with advancements in lens technology and improvements in surgical techniques. This article reviews developments in this field and current available lens options in the treatment of presbyopia.

Pupil size influence on the intraocular performance of the multifocal AMO-Array intraocular lens in elderly patients

PURPOSE

To study the relationship between pupil size and AMO-Array multifocal intraocular lens (MIOL) performance in a population of elderly patients.

METHODS

This prospective trial included 62 patients (mean age 76 years; range 70 to 86) undergoing bilateral cataract phacoemulsification and MIOL (AMO-Array SA-40N, Allergan) implantation. Patients were divided into two groups based on preoperative pupil diameter: small pupil group (pupil size of 2.5-2.9 mm; 45 subjects) and large pupil group (pupil size of 3-5 mm; 17 subjects). The analysis included uncorrected (UC) and best-corrected (BC) near and distance visual acuity (VA), spectacle dependence, and photic phenomena complaints (postoperative follow-up 16.6+/-6.2 months; range 11-26 months).

RESULTS

Patients in the small pupil group showed postoperatively significantly higher distance UCVA and BCVA, but lower near UCVA compared to those in the large pupil group (Mann-Whitney test, p< or = 0.02). Patients with small pupils also tended to: be more (not statistically significant) spectacle independent for distance (73.3% versus 47.1%) and spectacle-dependent for near vision (55.6% versus 28.4%); report significantly less photic phenomena complaints (37.8% versus 93.1%, chisquare test, p<0.001); and, more satisfied with the surgery (95.5% versus 76.5%). Posterior capsular opacification (PCO) was observed in 19.4% of the patients.

CONCLUSIONS

Bilateral AMO-Array MIOL implantation in elderly patients seems to be an effective and safe surgical procedure that improves distance and near UCVA, providing spectacle independence in many cases. The use of these MIOLs, however, can induce photic phenomena and cause PCO. Patients with small preoperative pupils (<3 mm) presented less photic phenomena complaints and expressed a higher visual outcome satisfaction after surgery.

Comparing the 1CU accommodative, multifocal, and monofocal intraocular lenses: a randomized trial

OBJECTIVE

To compare the binocular near vision performance in patients implanted with the 1CU accommodating intraocular lens (IOL) with a multifocal and monofocal IOL.

DESIGN

Prospective, randomized, double-masked clinical trial.

PARTICIPANTS

Ninety patients presenting for cataract surgery to the Department of Ophthalmology, Hillingdon Hospital were randomized to receive the 1CU accommodative IOL, a multifocal IOL, or a monofocal IOL (control group).

METHODS

Patients underwent bilateral sequential phacoemulsification with implantation of 1 of the 3 IOL types and were assessed at 3 and 18 months after second-eye surgery.

MAIN OUTCOME MEASURES

Logarithm of the minimum angle of resolution distance and near visual acuities (VAs) (unaided and distance corrected), contrast sensitivity, and accommodative amplitude (near point and defocusing) were measured at 3 and 18 months. Reading speed was assessed at 18 months, and glare symptoms and spectacle independence were compared using a standardized questionnaire.

RESULTS

Mean unaided and distance-corrected binocular near VAs were similar in the 1CU and multifocal and were significantly higher than the control group's (P<0.02). There was no significant difference in reading speed between any of the groups, but critical print sizes were similar in the 1CU and multifocal groups and significantly better than the control group's (P = 0.02). The accommodative range was highest in the multifocal group and lowest in the control group, and there was no significant difference between the 1CU and control groups for defocus or near point at 18 months. Of the 1CU group and control group, 71.4% and 63.2%, respectively, experienced no glare at 18 months, compared with only 25% of the multifocal group (P = 0.01). Of the 1CU group and multifocal group, 19% and 27.3%, respectively, were completely spectacle independent at 18 months; none of the control group was (P = 0.05).

CONCLUSIONS

The 1CU accommodating IOL provides improved near vision compared with a monofocal IOL. There is a discrepancy between the near function and accommodative amplitude measured in the 1CU. The multifocal provides excellent near acuity, but photopic phenomena remain a problem inherent in the lens design.

Development of a near activity visual questionnaire to assess accommodating intraocular lenses

PURPOSE

To develop a questionnaire that subjectively assesses near visual function in patients with 'accommodating' intraocular lenses (IOLs).

METHODS

A literature search of existing vision-related quality-of-life instruments identified all questions relating to near visual tasks. Questions were combined if repeated in multiple instruments. Further relevant questions were added and item interpretation confirmed through multidisciplinary consultation and focus groups. A preliminary 19-item questionnaire was presented to 22 subjects at their 4-week visit post first eye phacoemulsification with 'accommodative' IOL implantation, and again 6 and 12 weeks post-operatively. Rasch Analysis, Frequency of Endorsement, and tests of normality (skew and kurtosis) were used to reduce the instrument. Cronbach's alpha and test-retest reliability (intraclass correlation coefficient, ICC) were determined for the final questionnaire. Construct validity was obtained by Pearson's product moment correlation (PPMC) of questionnaire scores to reading acuity (RA) and to Critical Print Size (CPS) reading speed. Criterion validity was obtained by receiver operating characteristic (ROC) curve analysis and dimensionality of the questionnaire was assessed by factor analysis.

RESULTS

Rasch Analysis eliminated nine items due to poor fit statistics. The final items have good separation (2.55), internal consistency (Cronbach's alpha=0.97) and test-retest reliability (ICC=0.66). PPMC of questionnaire scores with RA was 0.33, and with CPS reading speed was 0.08. Area under the ROC curve was 0.88 and Factor Analysis revealed one principal factor.

CONCLUSION

The pilot data indicates the questionnaire to be internally consistent, reliable and a valid instrument that could be useful for assessing near visual function in patients with 'accommodating' IOLS. The questionnaire will now be expanded to include other types of presbyopic correction.

Longterm results of 1 CU® accommodative intraocular lens implantation: 2-year follow-up study

PURPOSE

To evaluate the longterm efficacy of 1 CU accommodative intraocular lenses (IOLs) to restore near visual performance.

METHODS

This prospective study comprised 14 eyes previously included in a 6-month, case-control clinical trial, undergoing phacoemulsification and implantation of a 1 CU accommodative IOL. The main outcome measures were subjective refraction, uncorrected distance visual acuity (UCDVA), best corrected distance VA (BCDVA), distance-corrected near VA (DCNVA), best corrected near VA (BCNVA), and subjective amplitude of accommodation (AA). In addition, anterior and posterior capsule opacification were assessed. Patients were examined over a 2-year follow-up period.

RESULTS

Distance and near visual performance worsened after 6 months. Uncorrected DVA and BCDVA were 0.8 +/- 2.1 and 1.0 +/- 0.8 at 6 months and 0.4 +/- 0.1 and 0.6 +/- 0.1 at 1 year, respectively (p = 0.001). Distance-corrected NVA and BCNVA were 3.7 +/- 2.1 Jaeger (J) and 1.0 +/- 0.7 J at 6 months and 8.1 +/- 0.7 J and 1.5 +/- 0.5 J at 1 year, respectively (p = 0.001). Anterior and posterior capsule opacification were present, respectively, in 28% and 21% of patients at 6 months and in 100% of patients at 1 and 2 years (p < 0.001). After Nd:YAG laser capsulotomy (performed in 100% of patients), UCDVA and BCDVA increased to 0.7 +/- 0.2 (p = 0.007) and 1.0 +/- 0.1 (p = 0.001), respectively, at 2 years. Distance-corrected NVA improved to 7.3 +/- 0.5 J (p = 0.006). Mean AA was 1.9 +/- 0.8 D at 6 months, 0.3 +/- 0.2 D (p = 0.004) at 1 year and 0.3 +/- 0.2 D at 2 years.

CONCLUSIONS

Patients implanted with 1 CU IOLs lost their accommodation capacities with time because of the high incidence and degree of anterior and posterior capsule opacification. The accommodative lens material and design may have played a role in capsule fibrosis.

Meta-analysis of accommodating intraocular lenses

Accommodating intraocular lenses (IOLs) based on the concept of optic shift were introduced to restore accommodation after cataract surgery. Currently, 3 types of accommodating IOLs are commercially available: 1CU (HumanOptics), BioComFold (Morcher), and AT-45 Crystalens (eyeonics, Inc.). We present a meta-analysis of the peer-reviewed data from studies of these IOLs that use optic-shift measurements and visual acuity as the main outcome measures. In the 6 randomized controlled studies, 5 of which studied the 1CU IOL, the visual acuity results showed moderate to no improvement in near visual acuity compared with control IOLs and a statistically significant but small and inter-patient variable anterior shift of the IOL optic after pilocarpine stimulation. More clinical trials with randomized, controlled, and patient- and examiner-masked study designs that follow the guidelines of evidence-based medicine are needed to prove a benefit of accommodating focus-shift IOLs.

Potentially Accommodating 1CU Intraocular Lens: 1-year Results in 553 Eyes and Literature Review

PURPOSE

To investigate the advantages, clinical outcomes, and safety after implantation of the 1CU (HumanOptics AG) optic shift intraocular lens (IOL) in comparison with a conventional monofocal IOL.

METHODS

In a prospective non-randomized study, 553 eyes implanted with the 1CU IOL were examined. In a control group, a monofocal posterior chamber IOL (MCTE, Dr Schmidt) was implanted in 219 eyes. Follow-up was performed at 1, 6, and 12 months postoperatively. The clinical effect for near visual acuity was evaluated by subjective measurements using an accommodometer, defocusing curve, and Nieden charts.

RESULTS

No significant differences were noted in distance best spectacle-corrected visual acuity (BSCVA) between groups. Average near visual acuity with distance BSCVA for the 1CU was 0.41 and 0.35 for the control group. The difference in the accommodation response between both groups measured with the accommodometer was 11 cm (P < .01). The refraction tolerance for the 1CU was 0.25 D whereas the MCTE revealed no refraction tolerance (P < .01). Decentration and tilting of the 1CU resulted in explantation of three IOLs.

CONCLUSIONS

The 1CU indicates a minor statistical advantage of half a reading step towards monofocal IOLs measured with subjective methods in near point, defocusing curve, and near visual acuity with distance BSCVA. This could be due to pseudophakic accommodation by the optic shift mechanism or a result of additional pseudophakic pseudoaccommodation. The accommodative effect of the 1CU differed from patient to patient and was not predictable.

Predicting the performance of accommodating intraocular lenses using ray tracing

PURPOSE

To predict and compare the amount of accommodation achievable by pseudophakic accommodating intraocular lenses (IOLs) using optical ray-tracing analysis.

SETTING

Computational laboratory.

METHODS

Two-element IOLs (2E-IOL, with mobile front or back optical elements) were compared with single-element IOLs (1E-IOL). Modeling using computer-assisted ray tracing of both IOL types assumed lens elements were equiconvex/equiconcave. The 4 possible combinations of configurations representing a wide range of varying positive and negative power (up to +40 diopters [D]) of front and back optical elements were evaluated.

RESULTS

The 1E-IOLs offered limited amplitude of accommodation with axial shift (approximately 1.2 D/mm). For 2E-IOLs, configurations with high positive-power front elements returned the best amplitude of accommodation (up to approximately 3.0 D/mm when the front element power was +40 D).

CONCLUSIONS

Considering the maximum potential amounts of axial shifts available, 1E-IOLs were predicted to provide 1.0 D of accommodation or less and 2E-IOLs were predicted to provide up to 3.0 D to 4.0 D depending on design configuration and amount of axial shift achievable. Potential issues relating to accommodative aniseikonia and spherical aberration have been identified.

Intraokularlinsen zur Korrektur von Refraktionsfehlern

In this overview, the current status of intraocular lens surgery to correct refractive error is reviewed. The interventions are divided into additive surgery with intraocular lens implantation without extraction of the crystalline lens (phakic intraocular lens, PIOL) or removal of the crystalline lens with implantation of an IOL (refractive lens exchange, RLE). Phakic IOLs are constructed as angle-supported or iris-fixated anterior chamber lenses and posterior chamber lenses which are fixated in the ciliary sulcus. The implantation of phakic IOLs has been demonstrated to be an effective, safe, predictable and stable procedure to correct higher refractive errors. Complications are rare and differ for the three types of PIOL; for posterior chamber lenses these are mainly cataract formation and pigment dispersion. RLE is preferable in cases of high ametropia in which the natural lens has lost its accommodative effect. The main complications for myopic RLA include retinal detachment, while hyperopic refractive lens exchange may be associated with surgical problems in the narrower anterior eye segment.

Intraokularlinsen zur Korrektur von Refraktionsfehlern

In this overview, the current status of intraocular lens surgery to correct refractive error is reviewed. The interventions are divided into additive surgery with intraocular lens implantation without extraction of the crystalline lens (phakic intraocular lens, PIOL) or the removal of the crystalline lens with implantation of an IOL (refractive lens exchange, RLE). Phakic IOLs are constructed as angle-supported or iris-fixated anterior chamber lenses and posterior chamber lenses that are fixated in the ciliary sulcus. The implantation of phakic IOLs has been demonstrated to be an effective, safe, predictable and stable procedure to correct higher refractive errors. Complications are rare and differ for the three types of PIOL; for anterior chamber lenses these are mainly pupil ovalization and endothelial cell loss.