Visual Strehl Performance of IOL Designs with Extended Depth of Focus

Clinical Outcomes of Combined Phacoemulsification, Extended Depth-of-Focus Intraocular Lens Implantation, and Epiretinal Membrane Peeling Surgery

Background/Objectives: To evaluate the clinical efficacy and safety of combined phacoemulsification, extended depth-of-focus (EDOF) intraocular lens (IOL) implantation, and epiretinal membrane (ERM) peeling during vitrectomy surgery for treating patients with ERM, cataracts, and presbyopia. Methods: Patients with preexisting low-grade ERM who underwent cataract surgery with the implantation of an EDOF IOL were included. Corrected distance visual acuity (CDVA), uncorrected distance visual acuity (UDVA), uncorrected intermediate visual acuity (UIVA), uncorrected near visual acuity (UNVA), autorefraction and keratometry, manifest refraction, and central foveal thickness (CFT) were measured before surgery and at postoperative months 3 and 6. A monocular defocus curve was measured 6 months postoperatively. Furthermore, patients were instructed to report symptoms of photic phenomena at each visit. Results: In total, 16 eyes of 16 patients (median age, 59.5 years) were included in this study. Compared with those at baseline, the CDVA, UDVA, UIVA, UNVA, and CFT significantly improved at 3 and 6 months postoperatively. The defocus curve revealed that a visual acuity of 0.12 logarithm of the minimal angle of resolution or better was maintained from +0.5 to -1.5 diopters. No patients reported visual disturbances suggestive of photic phenomena, such as glare or halo. Conclusions: EDOF IOL implantation had excellent outcomes, including improved distance and intermediate visual acuity, functional near visual acuity, and absence of visual symptoms in patients who received phacovitrectomy to treat low-grade ERM.

Objective Versus Subjective Depth of Focus Correlation in Pseudophakic Eyes

PURPOSE

To develop a method for quantifying objective depth of focus (DOF) from the visual Strehl ratio based on the optical transfer function (VSOTF), measured on a ray-tracing aberrometer (iTrace; Tracey Technologies) and to compare it to the subjective clinical DOF in two groups of pseudophakic eyes with varying asphericity of the intraocular lenses (IOLs).

METHODS

In this cross-sectional study, two groups with negatively aspheric (Eyhance; Johnson & Johnson) and aspherically neutral (RayOne; Rayner) IOLs were assessed 3 to 9 months postoperatively. The patient assessments included: logarithm of the minimum angle of resolution visual acuity, refraction, defocus curves, and iTrace assessments. The primary outcome was to determine the threshold of VSOTF (%) corresponding to subjective DOF. Secondary outcomes were uncorrected (UDVA) and corrected (CDVA) distance visual acuities, manifest refraction, keratometry, and wavefront aberrometry. The specific threshold of VSOTF matching the subjective DOF was determined.

RESULTS

Forty-two eyes (21 patients in each IOL group) were analyzed. For the primary outcome, in the Eyhance versus the RayOne IOL group and all eyes together there was no significant difference between 25% (P = .10 vs .28; P = .07) and 30% (P = .55 vs .73; P = .58) VSOTF and subjective DOF, respectively. For secondary outcomes, UDVA was better in the Eyhance group (P = .02). There was no difference in CDVA, manifest refraction, and keratometry. There was a significant difference in total and internal spherical aberration between the two groups, although it was not clinically significant.

CONCLUSIONS

This study showed that a 25% to 30% threshold of VSOTF values on iTrace measurements (Nanavaty Threshold) gives an objective DOF estimate, equivalent to clinical DOF derived from the defocus curve irrespective of the IOL's optical profiles. [J Refract Surg. 2025;41(4):e310-e317.].

Jacobi-Fourier phase masks as ophthalmic elements to correct presbyopia

PURPOSE

Investigations into the correction of presbyopia have considered lens design, clinical implications and the development of objective metrics such as the visual Strehl ratio. This study investigated the Jacobi-Fourier phase mask as an ophthalmic element in the correction of presbyopia. The goal was to develop a contact or intraocular lens whose performance was largely insensitive to changes in pupil diameter.

METHODS

Numerical simulations based on Fourier optics were performed to evaluate three different Jacobi-Fourier polynomials, with the aim of providing a range of clear vision (1 Dioptre (D)). Performance was evaluated for three pupil sizes (6, 4 and 2 mm), while polychromatic images were simulated using three different wavelengths (656.3, 587.6 and 486.1 nm). The Neural Transfer function was included in the simulation. To validate the method and results, we used the Visual Strehl combined objective metric (VSCombined) currently used in visual optics. This metric gives more weight to the phase transfer function and is more suitable for non-symmetrical phase functions.

RESULTS

Numerical validation showed the suitability of the Jacobi-Fourier phase masks for extending the range of clear vision of presbyopic eyes, providing a visual acuity of at least 0.10 logMAR (6/7.5 Snellen) at all distances between 1 and 6 m. The results show a range of clear vision of 1D was not affected by changes in pupil size, an increase in retinal image contrast accompanied by image artefact reduction by increasing the radial order of the Jacobi-Fourier phase mask and a reduction of wavelength dependence of the retinal images. These results are supported by simulated images and the objective criterion VSCombined.

CONCLUSIONS

The use of Jacobi-Fourier phase masks as ophthalmic elements for presbyopic correction show promising results, with a good range of clear vision and reduced dependence on pupil size and chromatic aberration.

Visual and clinical outcomes after bilateral implantation of a novel extended depth of focus lens post cataract surgery

PURPOSE

To assess the visual and clinical outcomes after bilateral implantation of the novel extended depth of focus (EDOF) (AcrySof IQ Vivity) intraocular lens (IOL) using a micromonovision strategy.

METHODS

This was a prospective interventional study at a tertiary care center. Twenty patients (40 eyes) underwent bilateral implantation of AcrySof IQ Vivity IOL. Twelve weeks postoperatively, both uncorrected vision and corrected vision were assessed. Uniocular and binocular defocus curves with and without correction were noted subjectively as well as objectively on I-trace. Contrast sensitivity was assessed with a FACT (Functional Acuity Contrast Testing) machine, and objective parameters like modulation transfer function and Strehl ratio were also measured on I-Trace. Subjective quality of vision using a subjective questionnaire was also evaluated.

RESULTS

The mean binocular postoperative uncorrected distance visual acuity in LogMAR was -0.03 ± 0.09, the uncorrected intermediate visual acuity was 0.03 ± 0.09, and the uncorrected near visual acuity was 0.28 ± 0.18. All defocus curves were smooth and broad with the uncorrected defocus curve (with the micromonovision strategy) better than the corrected defocus curve. The subjective depth of focus (DOF = 3.73) was more than objective DOF (1.93) (P < 0.05). Photopic contrast was better than mesopic at all frequencies. All aberrations increased at 5 mm pupil size compared to 3 mm pupil size and were statistically significant, except for the total eye spherical aberration, which shows no significant difference at 3 mm and 5 mm pupil size (P = 0.27). Spectacle independence for distance, intermediate, and near was achieved in 100%, 94.7%, and 94.7% cases in this study, respectively.

CONCLUSIONS

Using the micromonovision strategy, the visual performance of this novel EDOF IOL was outstanding both subjectively and objectively.

Clinical Retinal Image Quality of a Non-diffractive Wavefront-Shaping Extended Depth of Focus (Vivity) Intraocular Lens

PURPOSE

To evaluate clinical retinal optical image quality following implantation of an extended depth of focus intraocular lens (EDOF IOL) (Vivity; Alcon Laboratories, Inc), and to compare it with a monofocal and a trifocal IOL.

METHODS

This prospective, comparative, case-control study included 88 eyes implanted with: (1) 19 monofocal IOLs (AcrySof SA60AT; Alcon Laboratories, Inc); (2) 38 EDOF IOLs (AcrySof IQ Vivity); and (3) 31 trifocal IOLs (AT LISA tri 839MP; Carl Zeiss Meditec AG). Total root mean square, ocular lower (LOA) and higher (HOA) order aberrations, point spread function (PSF) Strehl ratio (PSF with LOA), and PSF Strehl ratio excluding LOA (PSF without LOA) were analyzed using a Pyramidal WaveFront-based sensor aberrometer Osiris (Costruzione Strumenti Oftalmici) at two different pupil sizes (3 and 4 mm).

RESULTS

The trifocal IOL showed the highest PSF without LOA at both pupil sizes (0.52 ± 0.12 and 0.31 ± 0.07, respectively), followed by the AcrySof SA60AT (0.39 ± 0.10 and 0.27 ± 0.07) and AcrySof IQ Vivity (0.34 ± 0.11 and 0.24 ± 0.09) (P < .001). The AcrySof IQ Vivity and monofocal IOLs were comparable (P > .05). Despite the comparable postoperative low spherical equivalent among the IOL groups, the AT LISA tri 839MP retinal image quality (PSF with LOA) was the most severely affected by such residual refractive errors (dropped to 0.26 ± 0.06 at 3 mm; P < .001) compared to the monofocal AcrySof SA60AT (0.24 ± 0.07 at 3 mm) and EDOF Acrysof IQ Vivity (0.23 ± 0.06 at 3 mm) groups. The PSF with LOA was comparable (P > .05) among the three groups at both the 3-and 4-mm pupil size.

CONCLUSIONS

Although trifocal IOLs provided significantly better retinal image quality if influence of LOA is excluded, they also demonstrated to be the most sensitive to residual refractive errors. Both the EDOF Acrysof IQ Vivity and mono-focal AcrySof SA60AT IOLs showed a comparable retinal image quality, and they are also comparable with trifocal IOLs when considering the clinically real PSF (PSF with LOA). [J Refract Surg. 2023;39(2):103-110.].

Evaluating Optical Quality of a New Hydrophilic Enhanced Monofocal Intraocular Lens and Comparison to the Monofocal Counterpart: An Optical Bench Analysis

INTRODUCTION

The aim of the study was to analyze the optical properties of a new hydrophilic enhanced monofocal intraocular lens (IOL) using optical bench analysis and compare it with its monofocal counterpart.

METHODS

This laboratory study investigates the enhanced monofocal intraocular lens (L-333) and the monofocal counterpart (L-313) IOL by Teleon Surgical, Spankeren, Netherlands on the optical bench, using OptiSpheric IOL PRO2 (Trioptics, Germany) in order to assess the optical quality according to ISO 11979 with ISO-2 Cornea. IOLs (power 22.0 D) were evaluated regarding through frequency modulation transfer function (MTF), Strehl ratio (SR), and through focus MTF at 50 lp/mm using a 3.0-mm and a 4.5-mm aperture. Tilt and decentration were applied. In addition, wavefront measurements were obtained using WaveMaster® IOL 2 device (Trioptics, Germany) and analyzed.

RESULTS

Centered: The MTF (mean) at 50 lp/mm (L-333/L-313) with 3.0 mm aperture was 0.606/0.724 and with 4.5 mm aperture 0.330/0.409. The SR (mean) with 3.0 mm aperture was 0.586/0.809 and with 4.5 mm aperture 0.330/0.348. Decentered by 1 mm: The MTF (mean) at 50 lp/mm (L-333/L-313) with 3.0 mm aperture was 0.485/0.705 and with 4.5 mm aperture 0.255/0.374. The SR (mean) with 3.0 mm aperture was 0.457/0.739 and with 4.5 mm aperture 0.185/0.268. Tilted by 5 degrees: The MTF (mean) at 50 lp/mm (L-333/L-313) with 3.0 mm aperture was 0.577/0.657 and with 4.5 mm aperture 0.345/0.336. The SR (mean) with 3.0 mm aperture was 0.583/0.702 and with 4.5 mm aperture 0.269/0.237. In through focus MTF and aperture of 3.0 mm, the L-333 showed a peak of 0.41 with some enlarged depth of power of about 2 D. For the aperture of 4.5 mm, the MTF values of L-313 and L-333 were slightly reduced; L-333 showed an MTF peak of 0.23 and some reduced depth of power of about 1.5 D. Wavefront measurements showed no major aberrations for the L-313, while a combination of moderate increase in Z 4-0 and Z 6-0 with opposite sign was revealed for the L-333.

CONCLUSION

The enhanced monofocal Lentis Quantum (L-333) produces some enlarged depth of focus by combining spherical aberration of different order and opposite sign. The Lentis Quantum performs very well in comparison to the aspherical monofocal counterpart owing to its optical design. Results with large apertures were sufficient too, suggesting that  the lens is a good option in eyes with a wide pupil and thus in refractive surgeries of young patients.

Clinical and Aberrometric Evaluation of a New Monofocal IOL with Intermediate Vision Improvement

Purpose

The aim of the study was to evaluate the visual outcomes, aberrometric results, and subjective and objective optical qualities 12 months after implantation of a new monofocal intraocular lens (Physiol IsoPure 1.2.3) in comparison with a standard monofocal intraocular lens (Tecnis PCB00).

Materials and Methods

Cataract patients without ocular comorbidities had bilateral implantation of the IsoPure IOL or the PCB00 IOL. One month after eye surgery, the visual acuity and monocular defocus curve were assessed. Twelve months after surgery, the visual acuity, binocular defocus curve, contrast sensitivity, and subjective/objective optical quality were assessed. Furthermore, wavefront analysis was performed. The primary endpoint was the best distance correct/uncorrected visual acuity at intermediate and far distances. The secondary endpoint was an aberration evaluation of the IOLs and contrast sensitivity.

Results

The study comprised a total of 42 patients (84 eyes). Monocular and binocular uncorrected and corrected distance were similar between groups, and uncorrected intermediate visual acuity was significantly higher in the IsoPure group. There was no difference in contrast sensitivity and subjective and objective optical qualities. The optical aberrations at 3.0 and 5.0 mm aperture diameters were similar in both groups.

Conclusion

The IsoPure IOL, based on greater depth of focus than the aspheric monofocal IOL, may offer a good option for the distance and intermediate vision without increasing optical aberrations and any photic phenomena.

Extended depth-of-focus intraocular lenses: power calculation and outcomes

The extended depth-of-focus intraocular lenses (EDOF IOLs) represent one of the most exciting advancements in the field of lens surgery. EDOF IOLs promise an excellent visual experience, minimizing visual disturbances (ie, halos and glare) commonly associated with multifocal IOLs. The pros and cons of EDOF IOLs should be evaluated in comparison with other more traditional multifocal or monofocal IOLs. The aim of this review is to provide the most current information regarding EDOF IOLs for power calculating formulas, refractive outcomes, incidence of photic phenomena, and patient satisfaction.

Extended Depth-of-Field Intraocular Lenses: An Update

Extended depth-of-focus (EDOF) is a new intraocular lens (IOL) technology in the treatment of presbyopia. In contrast to multifocal (MF) IOLs, EDOF lenses create a single elongated focal point, rather than several foci, to enhance depth of focus. In this way, EDOF IOLs aim to reduce photic phenomena, glare, and halos, which have been reported in MF IOLs. A potential disadvantage is a decrease of retinal image quality if the amount of the aberrations is excessively increased. Frequently, EDOF IOLs are combined with MF optical designs; for this reason, EDOF IOLs are commonly a subject of confusion with optical multifocality concepts. The aim of this article is to clarify what an EDOF IOL is and to discuss the recently reported outcomes with these IOLs. We propose naming lenses that have combined optical designs as "hybrid IOLs."

Model of the light sword intraocular lens: in-vitro comparative studies

This work presents the first models of light sword intraocular lenses (LS IOLs) with angularly modulated optical power. We performed an experimental, comparative study with multifocal and extended depth of focus intraocular lenses, which are available on the market. The measurements conducted in an original optical bench were utilised for an analysis of point spread functions, elongated foci, modulation transfer functions and the areas defined by them. The LS IOL models perform homogeneous imaging in the whole range of designed defocus. The proposed concept of extended depth of focus seems to be promising for the development of presbyopia-correcting intraocular lenses capable of regaining fully functional vision.

Clinical and aberrometric evaluation of a new extended depth-of-focus intraocular lens based on spherical aberration

PURPOSE

To compare the refractive, visual, and aberrometric results with a new extended depth-of-focus intraocular lens (EDOF IOL) based on alternating positive and negative spherical aberration in the central 3.0 mm optical zone and an aspheric monofocal IOL of the same platform.

SETTING

Ophthalmology, University Hospital of Verona, Italy.

DESIGN

Prospective case series.

METHODS

Cataract patients free from other ocular disease had bilateral implantation of the EDOF Mini Well IOL or the monofocal Mini IOL. Four to 6 weeks after second-eye surgery, the refraction, visual acuity, defocus curve, contrast sensitivity, and photic symptoms were assessed. Wavefront analysis was performed. The primary endpoint of was the amplitude of the dioptric interval for 0.1 logarithm of the minimum angle of resolution (logMAR) visual acuity. The secondary endpoint was an aberration comparison between the two IOLs.

RESULTS

The study comprised two groups of 25 patients each. The corrected distance visual acuity was better with the monofocal IOL by 0.02 logMAR (P = .03). The 0.1 logMAR dioptric interval was 2.0 diopters (D) for the EDOF IOL and 1.0 D for the monofocal IOL (P < .001). The mean CDVA at -2.0 defocus was 0.15 logMAR ± 0.08 (SD) and 0.52 ± 0.14 logMAR, respectively (P < .001). There was no difference in contrast sensitivity or photic symptoms. The optical aberrations at 4.0 mm and 6.0 mm aperture diameters were similar in the two groups.

CONCLUSION

The EDOF IOL based on spherical aberration provided greater depth of focus than the aspheric monofocal IOL without increasing optical aberrations and with few photic symptoms.

The Light Sword Lens - A novel method of presbyopia compensation: Pilot clinical study

Purpose

Clinical assessment of a new optical element for presbyopia correction–the Light Sword Lens.

Methods

Healthy dominant eyes of 34 presbyopes were examined for visual performance in 3 trials: reference (with lens for distance correction); stenopeic (distance correction with a pinhole ϕ = 1.25 mm) and Light Sword Lens (distance correction with a Light Sword Lens). In each trial, visual acuity was assessed in 7 tasks for defocus from 0.2D to 3.0D while contrast sensitivity in 2 tasks for defocus 0.3D and 2.5D. The Early Treatment Diabetic Retinopathy Study protocol and Pelli-Robson method were applied. Within visual acuity and contrast sensitivity results degree of homogeneity through defocus was determined. Reference and stenopeic trials were compared to Light Sword Lens results. Friedman analysis of variance, Nemenyi post-hoc, Wilcoxon tests were used, p-value < 0.05 was considered significant.

Results

In Light Sword Lens trial visual acuity was stable in tested defocus range [20/25–20/32], Stenopeic trial exhibited a limited range of degradation [20/25–20/40]. Light Sword Lens and reference trials contrast sensitivity was high [1.9–2.0 logCS] for both defocus cases, but low in stenopeic condition [1.5–1.7 logCS]. Between-trials comparisons of visual acuity results showed significant differences only for Light Sword Lens versus reference trials and in contrast sensitivity only for Light Sword Lens versus stenopeic trials.

Conclusions

Visual acuity achieved with Light Sword Lens correction in presbyopic eye is comparable to stenopeic but exhibits none significant loss in contrast sensitivity. Such correction method seems to be very promising for novel contact lenses and intraocular lenses design.

Patient-reported outcomes of multifocal and accommodating intraocular lenses: analysis of 117 patients 2-10 years after surgery

Purpose

The purpose of this study was to determine the satisfaction levels of patients at least 2 years after cataract surgery implantation with bilateral accommodating or bilateral multifocal intraocular lenses (IOLs) and to determine the relative rate of spectacle independence and adverse symptoms in that same time frame.

Design

Patient questionnaire administered in a single-center private practice at least 2 years after cataract surgery with presbyopia-correcting IOL implantation.

Methods

Patients who had undergone uncomplicated cataract surgery with an accommodating or multifocal IOL implant were eligible for inclusion. Patients with visually significant non-IOL-related postoperative morbidity were excluded. Patients with astigmatism or residual refractive error were not excluded. The main outcome measure was patient satisfaction at least 2 years after IOL implantation.

Results

Sixty-eight patients who received accommodating lenses and 49 patients who received multifocal lenses completed the questionnaire. The mean age of all patients was 75.7 years at the time of survey; the mean number of years since cataract surgery was 5.4 years. Overall, there were no significant differences between the two groups or within each group between the different lenses used. About 90% of patients in each group were “very satisfied” or “somewhat satisfied” with their vision at least 2 years after the initial surgery. Conversely, only one in eleven patients found his vision to be worse than expected.

Conclusions

The majority of patients who received either accommodating or multifocal IOLs remain satisfied with their lens of choice more than 5 years after the original surgery. Glare and halos remain more noticeable in patients who received multifocal lenses.

Pupil size stability of the cubic phase mask solution for presbyopia

Presbyopia correction involves different types of studies such as lens design, clinical study, and the development of objective metrics, such as the visual Strehl ratio. Different contact lens designs have been proposed for presbyopia correction, but performance depends on pupil diameter. We will analyze the potential use of a nonsymmetrical element, a cubic phase mask (CPM) solution, to develop a contact or intraocular lens whose performance is nearly insensitive to changes in pupil diameter. We will show the through focus optical transfer function of the proposed element for different pupil diameters ranging from 3 to 7 mm. Additionally, we will show the images obtained through computation and experiment for a group of eye charts with different visual acuities. Our results show that a CPM shaped as 7.07  μm*(Z33-Z3-3)-0.9  μmZ20 is a good solution for a range of clear vision with a visual acuity of at least 0.1 logMar from 0.4 to 6 m for pupil diameters in the 3- to 7-mm range. Our results appear to be a good starting point for further development and study of this kind of CPM solution for presbyopia.

Intraocular Telescopic System Design: Optical and Visual Simulation in a Human Eye Model

Purpose. To design an intraocular telescopic system (ITS) for magnifying retinal image and to simulate its optical and visual performance after implantation in a human eye model. Methods. Design and simulation were carried out with a ray-tracing and optical design software. Two different ITS were designed, and their visual performance was simulated using the Liou-Brennan eye model. The difference between the ITS was their lenses' placement in the eye model and their powers. Ray tracing in both centered and decentered situations was carried out for both ITS while visual Strehl ratio (VSOTF) was computed using custom-made MATLAB code. Results. The results show that between 0.4 and 0.8 mm of decentration, the VSOTF does not change much either for far or near target distances. The image projection for these decentrations is in the parafoveal zone, and the quality of the image projected is quite similar. Conclusion. Both systems display similar quality while they differ in size; therefore, the choice between them would need to take into account specific parameters from the patient's eye. Quality does not change too much between 0.4 and 0.8 mm of decentration for either system which gives flexibility to the clinician to adjust decentration to avoid areas of retinal damage.

Power Profiles and In Vitro Optical Quality of Scleral Contact Lenses: Effect of the Aperture and Power

OBJECTIVE

To assess the power profile and in vitro optical quality of scleral contact lenses with different powers as a function of the optical aperture.

METHODS

The mini and semiscleral contact lenses (Procornea) were measured for five powers per design. The NIMO TR-1504 (Lambda-X) was used to assess the power profile and Zernike coefficients of each contact lens. Ten measurements per lens were taken at 3- and 6-mm apertures. Furthermore, the optical quality of each lens was described in Zernike coefficients, modulation transfer function, and point spread function (PSF). A convolution of each lens PSF with an eye-chart image was also computed.

RESULTS

The optical power fluctuated less than 0.5 diopters (D) along the optical zone of each lens. However, the optical power obtained for some lenses did not match with its corresponding nominal one, the maximum difference being 0.5 D. In optical quality, small differences were obtained among all lenses within the same design. Although significant differences were obtained among lenses (P<0.05), these showed small impact in the image quality of each convolution.

CONCLUSIONS

Insignificant power fluctuations were obtained along the optical zone measured for each scleral lens. Additionally, the optical quality of both lenses has showed to be independent of the lens power within the same aperture.

Assessment of imaging with extended depth-of-field by means of the light sword lens in terms of visual acuity scale

We present outcomes of an imaging experiment using the refractive light sword lens (LSL) as a contact lens in an optical system that serves as a simplified model of the presbyopic eye. The results show that the LSL produces significant improvements in visual acuity of the simplified presbyopic eye model over a wide range of defocus. Therefore, this element can be an interesting alternative for the multifocal contact and intraocular lenses currently used in ophthalmology. The second part of the article discusses possible modifications of the LSL profile in order to render it more suitable for fabrication and ophthalmological applications.