Monocular Defocus Curve Research Articles

Predicting the Postoperative Addition Power of a Multifocal Intraocular Lens at the Spectacle Plane.

To establish a simple clinical method of predicting addition power achieved with a multifocal intraocular lens (IOL). In this prospective cohort study, 41 patients were bilaterally implanted with the Bi-Flex MY multifocal IOL (Medicontur) with +3.50 diopters (D) near addition power. Monocular defocus curves were plotted for each patient and effective addition power was calculated as the dioptric difference between the distance and near inflection points of the defocus curve. Six biometry formulas (Haigis, Holladay, SRK/T, Hill RBF, Barrett Universal II, and Holladay 2) were used to predict the addition power at the spectacle plane. Mean effective addition power was 2.60 ± 0.29 D, with significant (P < .01) differences between the prediction methods. Significant differences were found between predicted and effective addition when the Holladay, SRK/T, Hill RBF, and Holladay 2 formulas were used. A moderate but significant correlation (r = 0.342, P = .033) was found with the Barrett formula, and this was also the method to show the least proportional bias with Bland-Altman analysis. The study demonstrates that the effective addition power can be predicted using the proposed simple clinical method derived using the Barrett Universal II formula. The proposed technique may have significant clinical value in screening for patients where ocular biometry may lead to aberrant addition power. [J Refract Surg. 2021;37(5):318-323.].

Clinical Outcomes with a Novel Extended Depth of Focus Presbyopia-Correcting Intraocular Lens: Pilot Study

PurposeTo evaluate the clinical outcomes of cataract surgery with implantation of a novel model of extended depth of focus (EDOF) intraocular lens (IOL).MethodsPilot case series enrolling a total of 27 eyes of 16 patients (49 to 84 years) undergoing uncomplicated phacoemulsification cataract surgery with implantation of the EDOF IOL Synthesis PLUS (Cutting Edge, Montpellier, France). Near (UNVA, uncorrected near visual acuity; DCNVA, distance-corrected near visual acuity) and distance visual acuity (uncorrected and corrected distance visual acuity, UDVA and CDVA), monocular defocus curve and refractive outcomes were evaluated during a 3-month follow-up.ResultsMean postoperative UDVA, UNVA and DCNVA were 0.11±0.17, 0.14±0.22 and 0.37±0.36 logMAR, respectively. A total of 84.6%, 91.7%, and 96.3% of eyes achieved postoperative UDVA, UNVA and CDVA of 0.20 logMAR or better. A total of 78.6% of eyes achieved postoperative DCNVA of 0.30 logMAR or better. Mean postoperative spherical equivalent was −0.76±0.53 D. The distance-corrected visual acuity was maintained on average over a value of 0.30 logMAR for the range of defocus levels between +1.00 and −1.50 D.ConclusionThe implantation of the Synthesis plus EDOF IOL after cataract surgery seems to provide functional levels of distance, intermediate and near visual acuity. The near visual performance with this new IOL might be significantly enhanced using a micro-monovision approach. The results of this pilot study should be confirmed in future clinical trials.

A Comparative Evaluation of Visual, Refractive, and Patient-Reported Outcomes of Three Extended Depth of Focus (EDOF) Intraocular Lenses.

ObjectiveTo compare visual, refractive, and patient-reported outcomes of patients implanted with one of three types of extended depth of focus (EDOF) intraocular lenses.SettingAsian Eye Institute, Philippines.DesignRetrospective cohort study.MethodsSubjects implanted with Symfony (Johnson and Johnson, USA), IC-8 (AcuFocus, USA), and WIOL (Medicem, Czech Republic) EDOF intraocular lenses were recruited. Spherical equivalent, uncorrected and corrected visual acuity, defocus curve, and modulation-transfer function, Strehl ratio, and visual Strehl optical transfer function values, photic phenomena, and questionnaire answers were measured and assessed.ResultsA total of 32 eyes with the Symfony lens, 30 with the IC-8 lens, and 32 with the WIOL lens were included in the study. Mean postoperative spherical equivalent was −0.24 D for the Symfony, −0.17 D for the IC-8, and 0.27 D for WIOL. There were no significant differences in postoperative monocular and binocular uncorrected and corrected visual acuity. On a monocular defocus curve, the IC-8 and Symfony showed significantly better vision than WIOL. The Symfony had significantly better modulation-transfer function, Strehl ratio, and visual Strehl optical transfer function. No difference was seen among the three lenses with regard to glare or starburst, while patient satisfaction remained high in all groups for far, intermediate, and near vision.ConclusionAll eyes implanted with the three EDOF designs achieved excellent far and intermediate vision, with acceptable near vision. The IC-8 and Symfony exhibited a better range of vision on defocus-curve testing. The Symfony showed superior results in quality of vision. Patient satisfaction was high in all three EDOF groups.

Reply.

We thank Dr. Galvis and team for the attentive reading of our study on defocus curves. In our study, we compared the visual performance of 4 presbyopia-correcting IOLs and found that the 4 IOLs provided patients with equally good corrected distance visual acuity (CDVA). The extended depth-of-focus IOL demonstrated a slightly better intermediate CDVA, however a worse near CDVA than the other IOLs, with only the panfocal IOL presenting a better intermediate VA at 50 cm. We agree that the patients' uncorrected vergence is 0.25 D for an object at 4 m distance. In our study, the manifest refraction was performed with Early Treatment Diabetic Retinopathy Study charts at 4 m distance, and the defocus curves were performed with the values of this manifest refraction. Thus, the vergence of 0.25 D of measuring VA at 4 m was already included in the manifest refraction used for defocus curve measurement, and consequently, the 4 m distance of the defocus curve can be seen as the reciprocal of the diopters used for measurement. The same defocus curve testing was used for all IOLs, allowing a relative comparison of the differences between the IOLs. Other published studies on the visual performance of IOLs, including that of Gundersen and Potvin, used the same methods to test VA and defocus curves.1–3 One of the main purposes of defocus curves is that they allow the comparison of the visual performance of IOLs with different designs, not just the simulation of visual performance in daily life. We agree that binocular measurements reflect more real-world viewing because of the presence of retinal disparity cues in addition to blur. However, the monocular defocus curve approach is suitable to compare the visual performance of various IOL designs. Because the main aim of our study was to compare the visual performance of presbyopia-correcting IOLs, the monocular defocus curve was the method of choice. The testing of positive IOLs in defocus curves is traditionally performed to compare the vision of preoperated patients with that of postoperated patients.4 We included positive defocus testing to allow the comparison of other published studies that had tested with an overcorrection of +1.00 to −4.00 D.2,3 We agree with the authors that positive IOL-simulated defocus testing takes some additional time; however, in our study, only 3 additional lens powers per eye were tested up to +1.50 D vs 8 lens powers for the myopic side up to −4.00 D.5 Thus, the impact on additional test time was rather low. In addition, defocus curves for both positive and negative IOLs have an important advantage in that they allow an understanding of how well residual refractive errors are tolerated by IOL designs and if the VA reduces monotonically as a function of defocus on this side. In our study, there were no differences between IOLs identified, with all IOLs showing a similar drop of VA as a function of induced positive IOLs. In conclusion, we agree that the relationship between lens vergence and distance defocus is essential for interpreting the resultant defocus curves as performed in our study.

Comparison of visual outcomes after bilateral implantation of two intraocular lenses with distinct diffractive optics.

PurposeThe aim of this study was to compare the visual outcomes and subjective visual quality between bilateral implantation of an extended depth of focus intraocular lens, J&J Vision Tecnis Symfony® ZXR00 (Group A) and bilateral implantation of a diffractive trifocal intraocular lens, Alcon Acrysof IQ PanOptix® TNFT00 (Group B).MethodsThis prospective, nonrandomized, comparative study of consecutive cases assessed 52 eyes of 26 patients operated on by the same surgeon (WTH) and binocularly implanted with multifocal intraocular lenses between May 2016 and July 2018. Binocular visual acuity for far, intermediate and near was tested in all cases. Ophthalmological evaluation included the measurement of binocular uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), uncorrected near visual acuity (UNVA) at 40 cm, uncorrected intermediate visual acuity (UIVA) at 70 cm, monocular visual defocus curve and the quality of life (QoL) questionnaire, National Eye Institute Visual Functioning Questionnaire - 25 ( NEI-VFQ 25).ResultsPostoperative UDVA was 0.00 and 0.09 logMAR (P<0.001), UIVA was 0.20 and 0.39 logMAR (P<0.001) and UNVA was 0.16 and −0.01 logMAR (P<0.001) in groups A and B, respectively; postoperative CDVA was −0.05 and 0.06 logMAR (P<0.001) in groups A and B, respectively.ConclusionBoth groups reported good subjective quality of vision regarding long, intermediate and short distances. Group A had a better performance for binocular UDVA, UIVA at 70 cm and CDVA, while regarding the monocular defocus curve, Group A outperformed Group B for long distances. Furthermore, Group B surpassed it in the short to very short distances, between the range of ≥2.00 D to 5.00 D of vergence. While Group A had a better performance regarding the vergences between 0.00 and 1.00 D (P<0.05) and at the vergence of +2.50 D (P=0.007). Group B outran Group A for UNVA at 40 cm.

First results with a new intraocular lens design for the individual correction of spherical aberration

To assess the feasibility of individual compensation of corneal spherical aberration with a custom intraocular lens (IOL). Department of Ophthalmology, Rudolf Virchow Klinikum Glauchau, Glauchau, Germany. Prospective case series. Cataract patients were randomized to receive an individual aberration-correcting IOL (Invidua-aA; Group A) or a standard aspheric aberration-free IOL of otherwise identical design (Aspira-aA; Group B). In Group A, the IOL was designed according to preoperative calculation of the corneal spherical aberration Z(4,0). The aim was to achieve an overall postoperative ocular spherical aberration close to zero. Four weeks and 3months postoperatively, the refraction, visual acuity (far, intermediate, and near distance), photopic and mesopic contrast sensitivities (with and without glare), defocus curve, corneal and ocular spherical aberration, and pupil size were measured. Group A, 57 eyes of 42 patients and Group B, 29 eyes of 27 patients. Preoperatively, there was no difference in corneal spherical aberration between groups (P>.05). Three months postoperatively, residual ocular spherical aberration Z(4,0) was significantly lower in Group A (P<.001). Photopic and mesopic contrast sensitivities (with and without glare) were significantly higher in Group A at most spatial frequencies. Monocular defocus curve and distance, intermediate, and near visual acuity outcomes did not differ significantly between groups. Implantation of a custom monofocal aspheric IOL effectively reduced overall ocular spherical aberration. Clinical outcomes indicate that IOLs with an individual spherical aberration correction improve functional vision, especially contrast sensitivity, compared with standard aberration-free IOLs.

Short term visual outcomes of a new trifocal intraocular lens

BackgroundToday, patients often expect to achieve spectacle independance after cataract surgery. New trifocal intraocular lenses have been developed to try and fullfill this demand. The purpose of this study is to report the short-term visual outcomes of a new trifocal intraocular lens (AcrySof PanOptix™).MethodsConsecutive adult patients undergoing cataract surgery with bilateral implantation of the study intraocular lens in a private practice clinic were considered for inclusion. Exclusion criteria were the presence of other ocular pathologies or preoperative astigmatism >1.5 diopters (D). Patients with intraoperative complications were excluded from analysis. One month after surgery patients underwent: monocular defocus curve; monocular and binocular uncorrected visual acuity in photopic and mesopic conditions, for far (4 m), intermediate (60 cm) and near (33 cm) distances and binocular contrast sensitivity. Patients completed a visual satisfaction questionnaire between 9 and 12 months after surgery.ResultsOne hundred and sixteen eyes of fifty-eight patients receiving bilateral implantation of the study intraocular lens were analysed. Mean binocular uncorrected visual acuity in photopic conditions was 0.03 LogMAR for far, 0.12 for intermediate and 0.02 for near distances. All patients achieved a binocular uncorrected visual acuity better than 0.3 LogMAR (20/40 Snellen equivalent) for distance and near vision and 94.8% of patients for intermediate vision. Mesopic binocular uncorrected visual acuity values were similar to photopic values. The monocular defocus curves showed that the best visual acuity was reached at a vergence of 0.00D. Visual acuity dropped slightly at −1.00D and peaked again at −2.00D. Visual acuities better than 0.2 LogMAR were maintained between −2.50D and +0.50D. Contrast sensitivity was high and similar in photopic and mesopic conditions. As regards patient-evaluated outcomes, only 2 patients (3.4%) were fairly dissatisfied with their sight after surgery. Three patients (5.1%) reported the need for spectacle correction for certain activities. All other patients (94.8%) reported never using spectacle correction.ConclusionsThe PanOptix trifocal IOL provides good short-term visual outcomes, with good intermediate performance and excellent patient-reported satisfaction. The similar values achieved in mesopic and photopic conditions in binocular uncorrected visual acuity and contrast sensitivity suggest low pupillary dependence for light distribution.Trial registration numberISRCTN60143265, retrospectively registered on the 24th of April 2017.

Spectacle plane add power of multifocal intraocular lenses according to effective lens position

ObjectiveTo evaluate the accuracy of predicting the spectacle plane add power of multifocal intraocular lenses (MIOLs) based on the effective lens position (ELP) using the Haigis formula. DesignRetrospective cross-sectional study. ParticipantsA total of 26 eyes from 18 consecutive patients who underwent phacoemulsification with Tecnis MIOL (Z*B00) implantation. MethodsThe postoperative spectacle plane add power of MIOLs was determined from the monocular defocus curve. The predicted add power error was defined as the difference between the predicted and postoperatively measured spectacle plane add power. The median absolute predicted add power error determined by the preoperatively estimated ELP using the Haigis formula was compared with power error calculated using the value presented by the manufacturer. The correlations among predicted add power error, postoperative spectacle plane add power, and back-calculated ELP were analyzed. ResultsThe median absolute predicted add power error calculated using the Haigis formula (0.13 D) was significantly smaller than that calculated using the value presented by the manufacturer (0.26 D). The predicted add power error determined by the value presented by the manufacturer was negatively correlated with back-calculated ELP. The postoperative spectacle plane add power was negatively correlated with back-calculated ELP in the ZKB00 IOL (n = 21). ConclusionsThe predicted spectacle plane add power of MIOLs using the ELP of the Haigis formula was more accurate than that using the value presented by the manufacturer. The spectacle plane add power of MIOLs decreased as ELP increased.

Influence of +3.00 D and +4.00 D near addition on functional outcomes of a refractive multifocal intraocular lens model

To clinically evaluate different near additions (adds) (+3.00 diopters [D] and +4.00 D) of the M-flex 630F refractive multifocal intraocular lens (IOL). Departments of Ophthalmology, University of Heidelberg, Germany, and Lithuanian University of Health Sciences, Kaunas, Lithuania. Clinical prospective nonrandomized unmasked study. Preoperatively, cataract patients were assigned to receive bilateral +3.00 D IOLs, +4.00 D IOLs, or +3.00 D (dominant eye) and +4.00 D (nondominant eye) IOLs. Follow-up examinations were performed up to 6 months postoperatively and included refraction, visual acuity (near at 40 cm and distance), the defocus curve, contrast sensitivity, and a subjective questionnaire. Fifty-two patients were enrolled. No significant differences were found in the visual acuity results (P>.05). Four to 6 months postoperatively, the following median uncorrected and corrected distance visual acuity, uncorrected and distance-corrected near visual acuity, and corrected near visual acuity (logMAR) were found in all patients: -0.08, -0.12, 0.20, 0.10, and 0.10. Ninety-eight percent of patients reported being satisfied. The highest near peak versus the biggest intermediate decline in the median monocular defocus curves comparing +3.00 D and +4.00 D multifocal IOLs (logMAR) were 0.16 at 40 cm versus 0.22 at 33 cm (P=.24) and 0.38 at 66 cm versus 0.54 at 50 cm (P<.01). Compared with the +4.00 D add, the +3.00 D near add gave better intermediate results in the defocus curve without compromising distance or near visual acuity.