Optical characterization and through-focus performance of two advanced monofocal intraocular lenses

PURPOSE

To compare the refractive power profile, subjective depth-of-field and objective optical quality of two advanced monofocal intraocular lenses (IOLs) designed to improve intermediate vision.

METHODS

This prospective study evaluated forty-six eyes of twenty-three patients, aged 54-68 years, binocularly implanted with two monofocal enhanced intraocular lenses (IOLs), the Tecnis Eyhance and the Physiol Isopure. Subjective through-focus visual acuity curves were obtained by placing trial lenses in front of the eye while wearing its best spherical-cylindrical correction for distance. Objective optical quality was defined as the area under the modulation transfer function, calculated from the wavefront maps measured with a high-resolution aberrometer. The optical design of both lenses was compared based on their refractive power profiles measured with the lenses immersed in saline solution.

RESULTS

Both lenses have progressive aspherical geometries, in which the sagittal power decreases rapidly from the center to the edge of the optical zone. Mean monocular through-focus curves show a best corrected distance visual acuity of - 0.02 logMAR with both lenses. Through-focus visual acuity was marginally higher for the Eyhance, with a difference of 1 letter at the defocus position of - 0.5D and 3 letters between - 1.0D and - 2.0D. Objective assessment of optical quality revealed only a difference of about 2 points in MTF area at distance.

CONCLUSION

Both IOLs use a similar approach to improve intermediate vision. The Eyhance showed marginally better subjective performance than the Isopure at the target vergences between - 1.00D and - 2.00D, although these results did not reach statistical significance and were not replicated by the objective findings.

BCLA CLEAR Presbyopia: Evaluation and diagnosis

It is important to be able to measure the range of clear focus in clinical practice to advise on presbyopia correction techniques and to optimise the correction power. Both subjective and objective techniques are necessary: subjective techniques (such as patient reported outcome questionnaires and defocus curves) assess the impact of presbyopia on a patient and how the combination of residual objective accommodation and their natural DoF work for them; objective techniques (such as autorefraction, corneal topography and lens imaging) allow the clinician to understand how well a technique is working optically and whether it is the right choice or how adjustments can be made to optimise performance. Techniques to assess visual performance and adverse effects must be carefully conducted to gain a reliable end-point, considering the target size, contrast and illumination. Objective techniques are generally more reliable, can help to explain unexpected subjective results and imaging can be a powerful communication tool with patients. A clear diagnosis, excluding factors such as binocular vision issues or digital eye strain that can also cause similar symptoms, is critical for the patient to understand and adapt to presbyopia. Some corrective options are more permanent, such as implanted inlays / intraocular lenses or laser refractive surgery, so the optics can be trialled with contact lenses in advance (including differences between the eyes) to better communicate with the patient how the optics will work for them so they can make an informed choice.

Clinical performance and shape analysis of trifocal intraocular lenses via scanning electron microscopy

BACKGROUND

To evaluate visual performance after implantation of the TFNT (Acrysof Panoptix, Alcon, Fort Worth, Texas, USA) and CNWT (Clareon Panoptix, Alcon, Fort Worth, Texas, USA) intraocular lens (IOL), and compare the lens shape observed by scanning electron microscope (SEM).

METHODS

Eighteen patients (18 eyes) received implantation of the CNWT and Twenty patients (20 eyes) received implantation of the TFNT. Exclusion criteria were previous ocular surgeries, ocular pathologies, or corneal abnormalities. Intervention or Observational Procedure(s): Postoperative examination at 1 months including manifest refraction; evaluation of refractive error, distance-corrected visual acuity (DCVA) at 5 m, 1 m, 70 cm, 50 cm, 40 cm, and 30 cm, slit-lamp examination; defocus curve testing; contrast sensitivity (CS) was performed. The lens shape of the TFNT and the CNWT was examined under SEM.

RESULTS

Mean spherical equivalent was 0.11 ± 0.41 D (CNWT group) and 0.12 ± 0.34 D (TFNT group) 1 month postoperation. DCVA and defocus curve showed no significant difference between the two groups. CS was significantly higher in CNWT group than TFNT group at spatial frequencies of 6 cycles per degree (cpd). Observation of the IOL with a scanning electron microscope (SEM) revealed that CNWT group had improved diffraction structure and edge processing accuracy compared to TFNT group.

CONCLUSION

There was no significant difference between the two groups in the defocus curve and visual acuity at all distances. CS was better in the CNWT group than in the TFNT group. IOL surface features may affect CS.

Red and green defocus curves and duochrome test in different age groups

PURPOSE

To compare the eye defocus curves (DCs) obtained with stimuli on red, green, and white backgrounds and to investigate the applicability of the duochrome test (DT) in different age groups.

METHODS

12 elderly (ELD: 59.3 ± 3.9 years) and 8 young (YG: 22.1 ± 1.1 years) subjects were recruited. An optometric assessment with the DT was carried out to obtain the subjective refraction at distance. DCs at distance on green, white, and red backgrounds were measured and the following parameters were deduced: dioptric difference between red-green, green-white, red-white focal positions (minima of the DCs), best corrected visual acuity (BCVA), and widths of the DCs for red, green, and white.

RESULTS

The DC difference between the green-white focal positions (mean ± standard deviation) was -0.12±0.17 diopters (D) (ELD, p = 0.012) and -0.11±0.12 D (YG, p = 0.039), while the red-white difference was not statistically significant. The DC red-green difference was 0.20±0.16 D (ELD, p = 0.002) and 0.18±0.18 D (YG, p = 0.008). The ELD BCVA with green background was significantly worse than BCVA with red (p = 0.007) and white (p = 0.007). The mean value of the DC's width in ELD for green (1.01±0.36 D) was higher than for red (0.77±0.21 D) and for white (0.84±0.35 D), but with no statistical significance.

CONCLUSION

Both age groups showed a slight focusing preference for red when using white light. Moreover, ELD showed a worse BCVA with a green compared to a red background. Despite these results deduced by DC analyses, these aspects do not compromise the possibility of using the DT in clinical practice both in the young and in the elderly. Furthermore, the difference of about 0.20 D between red-green DC in both groups confirms the clinical appropriateness of the widespread use of 0.25 D step as the standard minimum difference in power between correcting lenses.

Depth of field and visual performance after implantation of a new hydrophobic trifocal intraocular lens

Purpose

To assess the depth of field (DOF) by means of defocus curve analysis applying different visual acuity criteria in patients following cataract surgery and bilateral implantation of a new trifocal diffractive intraocular lens (IOL).

Methods

Fifty eyes of 25 consecutive patients who underwent implantation of the Asqelio™ trifocal IOL (AST Products Inc., USA) were enrolled in this observational prospective study. Monocular subjective DOF was obtained from defocus curves with absolute and relative criteria of tolerance for different visual acuities values. Patient’s visual satisfaction, postoperative refraction and visual acuity at far, intermediate (67 cm) and near (40 cm) distances were also measured at 1 and 3-months post-surgery. Analysis of variance was used to assess differences in refractive error after the surgical procedure, and paired t-tests were used to assess differences in VA. Patient satisfaction results were reported as percentages.

Results

Spherical equivalent was 0.05 ± 0.23 D and residual cylinder 0.01 ± 0.23 D 3-months after the surgery. Absolute DOF obtained was 3.29 ± 0.91 D considering 0.1 LogMAR as cut-off value, and 4.82 ± 0.69 D when 0.3 logMAR as cutoff value. Relative DOF considering a drop of 0.1 logMAR from maximum visual acuity was 2.57 ± 0.82 D, and 1.27 ± 0.70 D when a drop of 0.04 logMAR was considered. Visual acuities obtained 3-months after the surgery were 0.03 ± 0.13, − 0.05 ± 0.06, 0.03 ± 0.08 and 0.04 ± 0.08 logMAR for uncorrected and best-corrected for distance, and best distance-corrected for intermediate and near distances, respectively. Average response to visual satisfaction queries was 8.24/10 at distance, 8.04/10 at intermediate, and 7.88/10 at near.

Conclusions

Patients implanted with this trifocal IOL showed a significant improvement in visual acuity at different distances providing wide absolute and relative DOF values. The outcomes demonstrate that this lens is predictable yielding good patient satisfaction rates.

Comparison of visual results and optical quality of two presbyopia-correcting intraocular lenses: TECNIS symfony versus TECNIS synergy

PURPOSE

This study compared the extended depth of focus (EDOF) intraocular lens (IOL) (ZXR00; Tecnis® Symfony^®, Johnson & Johnson Vision, Santa Ana, CA, USA) and a new presbyopia-correcting IOL that combines EDOF and multifocal profiles (ZFR00; Tecnis^® Synergy^®, Johnson & Johnson Vision, Santa Ana, CA, USA) with the same material.

METHODS

The medical records of patients undergoing cataract surgery with ZXR00 or ZFR00 implantation between March 2021 and July 2021 and with the data available for the 3-month visit were reviewed. The uncorrected near, intermediate, and distance visual acuity (VA), corrected distance VA, defocus curves, refractive errors (RE), optical quality parameters, and patient-reported visual performance parameters were the main outcome measures.

RESULTS

Among the twenty-three enrolled patients, twelve patients (21 eyes) received ZXR00 and nine patients (17 eyes) received ZFR00. The mean age of the patients was 59.6 ± 10.6 (range: 49 to 70) and 65.2 ± 8.2 (range: 45 to 82) years in ZXR00 and ZFR00 groups, respectively, without significant difference. There was not a significant difference between the two groups in terms of baseline parameters and postoperative RE. The ZFR00 group showed markedly superior intermediate and near VA (p < 0.001 for all) at 3 months postoperatively. In terms of optical quality, ZXR00 was significantly better than ZFR00 (p < 0.001).

CONCLUSIONS

Both IOLs had comparable distance VA. ZFR00 IOL was superior for intermediate and near visual acuity, but ZXR00 IOL was better for optical quality. Research with more participants is needed to support this finding.

Comparison of an aspheric monofocal intraocular lens with the new generation monofocal lens using defocus curve

Purpose:

The aim of this study was to compare the visual outcomes of two monofocal intraocular lenses (IOLs), with emphasis on the defocus curve.

Methods:

A total of 116 consecutive eyes with cataract, undergoing phacoemulsification with IOL implantation were included in the observational case series, and divided into two groups. 71 eyes were implanted with Tecnis Eyhance and 45 with Tecnis 1 monofocal IOL. Eyes with ocular comorbidities, previous ocular surgeries and corneal astigmatism >1 Diopters (D) were excluded from the study. Complete ophthalmic evaluation including uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), uncorrected intermediate visual acuity (UIVA), corrected intermediate visual acuity (CIVA), uncorrected visual acuity (UNVA), corrected near visual acuity (CNVA) was noted and defocus levels ranging from - 4.00 D to + 1.00 D were plotted postoperatively in both groups.

Results:

Uncorrected intermediate visual acuity (UIVA) and uncorrected near visual acuity (UNVA) was significantly better in Tecnis Eyhance group compared to Tecnis 1 monofocal. Both the IOLs have similar performance for distance vision but visual acuity at intermediate and near is significantly better with Tecnis Eyhance compared to Tecnis 1 piece IOL.

Conclusion:

Tecnis Eyhance IOL with its better defocus curve, not only provides good distance, but intermediate vision as well. With significantly better visual acuity across the range of near and intermediate vision, Tecnis Eyhance IOL can prove to be a viable and reasonable option for patients who are more dependent on intermediate vision in daily activities.

Comparison of visual and refractive outcomes of diffractive bifocal toric and trifocal toric intraocular lenses 12 months after implantation in patients with moderate to high myopia

PURPOSE

To compare the visual and refractive outcomes of bifocal toric and trifocal toric intraocular lenses (IOL) in patients with moderate to high myopia at 12 months after implantation.

METHOD

This is a prospective and comparative study. In 120 eyes with moderate to high myopia and astigmatism, bifocal toric IOLs (n = 60 eyes) or trifocal toric IOLs (n = 60 eyes) were implanted. Eyes with axial lengths from 24.0 to 26.5 mm were included. Postoperative examinations measured near, intermediate, and distance visual acuity (VA), along with refractive measurements, binocular defocus curves, and patient satisfaction with the National Eye Institute Visual Function Questionnaire.

RESULTS

For uncorrected- and corrected distance intermediate VA, the trifocal group showed significantly better VA at 1, 3, 6, and 12 months than the bifocal group. Driving subscale scores from the questionnaire were significantly better in the trifocal than the bifocal group. Concerning the binocular defocus curve, uncorrected distance VA was significantly higher in the trifocal than bifocal group at test distances of -1.5 D.

CONCLUSIONS

Both trifocal and bifocal toric IOLs effectively corrected the near, intermediate, and distance vision in patients with moderate to high myopia and astigmatism. However, intermediate vision was significantly better in eyes with trifocal than bifocal toric IOLs.

Optical and visual quality assessment of an extended depth-of-focus intraocular lens based on spherical aberration of different sign

PURPOSE

To assess the optical quality and the visual performance of patients implanted with an extended depth-of-focus (EDOF) intraocular lens (IOL).

METHODS

Thirty-eight eyes underwent implantation of the Mini WELL Ready EDOF IOL and were evaluated at 3-months postsurgery. Higher-order aberrations (HOAs) and modular transfer function (MTF) were measured at 3- and 5-mm pupils. Binocular uncorrected-distance visual acuity (UDVA) and corrected-distance visual acuity (CDVA), uncorrected-distance intermediate visual acuity (UIVA) and corrected-distance intermediate visual acuity (CDIVA) at 80 cm, and uncorrected-distance near visual acuity (UNVA) and corrected-distance near visual acuity (CDNVA) at 40 cm were obtained. Postoperative refraction, binocular defocus curve, halometry and subjective ad hoc patients' questionnaire were also evaluated.

RESULTS

HOAs were 0.171 ± 0.046 µm and 0.406 ± 0.137 µm at 3 and 5 mm, respectively. MTFs decreased as the spatial frequency increased being comparable for both pupils. 92.10% of eyes were within ± 1.00D, and the mean postoperative spherical equivalent was - 0.25 ± 0.65D. Mean UDVA, UIVA and UNVA were 0.06 ± 0.12, 0.05 ± 0.10 and 0.26 ± 0.28 logMAR, respectively. Mean CDVA, CDIVA and CDNVA were - 0.01 ± 0.08, 0.06 ± 0.11 and 0.24 ± 0.12 logMAR, respectively. Defocus curve showed a continuous range of vision, especially at intermediate distances. Mean discrimination index was 0.79 ± 0.04. Questionnaire revealed that about 79% of patients reported a high or moderately high satisfaction with the procedure, and about 95% of patients would undergo the same procedure again.

CONCLUSIONS

The Mini WELL Ready EDOF IOL provided good optical and visual quality with high level of patient satisfaction and seems to be a valuable option to provide unaided vision at different distances minimizing visual disturbances.

Characterization of optical performance with defocusing curve: Analysis of two refractive intraocular lens models with high and medium addition

PURPOSE

To characterize the optical performance of two models of refractive bifocal intraocular lenses, with medium and high addition, using defocus curves.

METHODS

20 eyes from 20 subjects were included in this study. 10 eyes underwent caratact surgery with an implant of a medium addition refractive bifocal intraocular lens (IOL) (Lentis LS-313 MF20) and the other 10 eyes underwent cataract surgery with an implant of a high addition refractive bifocal IOL (Lentis LS-313 MF30). Six weeks after surgery, subjective refraction and defocus curve were made.

RESULTS

Mean final residual refraction in spherical equivalent was +0.10±0.07D in the LS-313MF30 group and +0.12±0.10D in the LS-313MF20 group. Defocus curve showed a different optical performance in intermediate/near distance depending on the IOL model. The medium addition IOL provided good visual acuity (VA) at far and intermediate distance up to 50cms, and the high addition IOL provided better VA in near distance up to 25cms.

CONCLUSIONS

The high addition intraocular lens provides better visual acuity in the spatial range from infinity to the point close to 25cm. The medium addition intraocular lens provides excellent visual acuity in far and intermediate vision. The defocus curve seems to be a valid and reproducible tool for evaluating the optical behavior of multifocal sector refractive lenses.

Quality of vision, patient satisfaction and long-term visual function after bilateral implantation of a low addition multifocal intraocular lens

PURPOSE

The aim of the current study was to compare the quality of vision, contrast sensitivity and patient satisfaction with a biaspheric, segmented, rotationally asymmetric IOL (Lentis Comfort LS-313 MF 15-Oculentis GmbH, Berlin, Germany) as opposed to those of a monofocal IOL.

METHODS

This prospective single-blind comparative study included two groups of patients affected by bilateral senile cataract who underwent lens extraction and IOL implantation. The first group received a bilateral implantation of a monofocal IOL, and the second group received a bilateral implantation of the Comfort IOL. Twelve months after surgery uncorrected and corrected visual acuity at different distances (30, 50, 70 cm and 4 m), defocus curve and contrast sensitivity were assessed. Patient's satisfaction and spectacle independence were evaluated by mean of the NEI RQL-42 questionnaire.

RESULTS

No significant differences were found between the groups in terms of near vision. The group of patients implanted with a Comfort IOL obtained the best results at intermediate distances (50 and 70 cm P < .001). Both groups showed an excellent uncorrected distance visual acuity (4 m). No statistically significant differences were found in terms of corrected near, intermediate and distance visual acuity. Concerning contrast sensitivity, no statistically significant differences between the groups were observed at any cycles per degree. The NEI RQL-42 questionnaire showed statistically significant differences between the group for "near vision" (P = .015), "dependence on correction" (P = .048) and "suboptimal correction" (P < .001) subscales.

CONCLUSION

Our findings indicated that the Comfort IOL +1.5 D provides a good intermediate spectacle independence together with a high quality of vision, with a low amount of subjective symptoms and a contrast sensitivity similar to those obtained with a monofocal IOL.