Differences Between Simulated Keratometry and Total Corneal Power in Eyes With Keratoconus and a Formula to Improve IOL Power Calculation Results.

PURPOSE: To compare simulated keratometry (SimK) and total corneal power (TCP) in keratoconic eyes, to determine whether the differences are systematic and predictable and to evaluate an adjusted TCP-based formula for intraocular lens (IOL) power calculation. METHODS: In a consecutive series of keratoconic eyes, measurements of SimK, TCP, posterior keratometry, and anterior and posterior corneal asphericities (Q-values) were retrospectively collected. The difference between SimK and TCP was linearly correlated to the biometric parameters. In a separate sample of keratoconic eyes that had undergone cataract surgery, IOL power was calculated with the Barrett Universal II, Hoffer QST, Holladay 1, Kane, and SRK/T formulas using the SimK and an adjusted TCP power. The respective prediction errors were calculated. RESULTS: A total of 382 keratoconic eyes (271 patients) were enrolled. An increasing overestimation of SimK by TCP was detected from stage I to III, with a significant correlation between the SimK and TCP difference and SimK in the whole sample (P < .0001, r2 = 0.1322). Approximately 7% of cases presented an underestimation of SimK by TCP. IOL power calculation with the adjusted TCP improved outcomes, achieving a maximum of 80% of eyes with a prediction error within ±0.50 diopters with the Hoffer QST, Holladay 1, and Kane formulas. CONCLUSIONS: Overall, SimK overestimated TCP. Such a difference could not be predicted by any variable. The proposed TCP-adjustment formula (TCPadj = TCP + 0.56 diopters) in keratoconic eyes for IOL power calculation might be valuable for improving refractive outcomes. [J Refract Surg. 2024;40(4):e253-e259.].

Functional Classification of Intraocular Lenses Based on Defocus Curves: A Scoping Review and Cluster Analysis.

PURPOSE: To explore a potential functional classification of intraocular lenses (IOLs) based on monocular visual acuity defocus curves (VADCs) as a primary end-point. METHODS: A systematic literature search was conducted using PubMed. Two independent reviewers screened the literature for inclusion and data extraction. Inclusion criteria were full-text primary clinical studies of IOLs, published in English from 2010 onward, involving patients undergoing cataract or refractive lens exchange. A cluster analysis was conducted to explore similarities in the range of field (RoF) and increase of visual acuity from intermediate to near (ΔVA). RESULTS: A total of 107 studies were ultimately included from the 436 identified in the systematic search, with an additional 5 studies added through the snowballing technique search. The cluster analysis was conducted using 69 reports that included monocular VADCs. Two main categories were identified based on the achieved RoF for 0.2 and 0.3 logMAR: full (FRoF) and partial (PRoF) RoF IOLs. Three subcategories were identified for FRoF depending on ΔVA: continuous (FRoF-C), smooth (FRoF-Sm), and steep (FRoF-St). On the other hand, PRoF IOLs shared the characteristic of monotonous decrease in visual acuity and were subclassified into two subcategories depending on the achieved RoF: narrowed (PRoF-N) and extended (PRoF-Ex). An additional subcategory was added to PRoF, enhanced (PRoF-En), for 7 reports alternating between PRoF-N and PRoF-Ex depending on the use of 0.2 or 0.3 logMAR as a cut-off for calculating the RoF. CONCLUSIONS: IOLs can be functionally classified into six types depending on the RoF and shape of the monocular VADC. [J Refract Surg. 2024;40(2):e108-e116.].

Cataract Grade and Pupil: Comparison Between Conventional Phacoemulsification and Low-Energy Femtosecond Laser Assisted Cataract Surgery.

Purpose: This study presents a comparison of pupil changes according to cataract grade between low-energy femtosecond laser-assisted cataract surgery (FLACS) and conventional phacoemulsification (CP) in the same patient. Patients and Methods: Data from surgical records from patients submitted to cataract surgery with CP in one eye and FLACS in the other were retrospectively reviewed. The inclusion criterion was both eyes of the same patient having the same cataract grade in accordance with Lens Opacity Classification System (LOCS) III. Total pupil variation (TPV) was measured after recorded images, with intraindividual comparison between techniques, according to cataract grade (≤3 and >3), age and cumulative dissipated energy (CDE). Results: The study included a total of 124 eyes of 62 patients (mean age 72.65 ± 7.64 years). Analysis showed a statistically significant difference in TPV between techniques in the grade ≤3 cataract group (0.08 ± 0.22 mm²; p=0.034), with less pupil narrowing with FLACS, but not in the grade >3 group (0.01 ± 0.23 mm²; p=0.849). Regarding CDE, a significant difference (p<0.001) was found between techniques in both softer and harder cataracts, with lower values for FLACS. Correlation between CDE and TPV was significant for CP (p=0.021) but not for FLACS (p=0.922). TPV was significantly lower in older patients (age >74 years) for both techniques (p<0.001). Conclusion: There was a statistically significant difference between techniques (although of mild clinical relevance), with less reduction of pupil area with FLACS in softer cataracts (grade ≤3), as compared to CP. Higher levels of CDE are associated with more pupil narrowing in CP.

Managing low corneal astigmatism in patients with presbyopia correcting intraocular lenses: a narrative review.

Cataract surgery has become a refractive procedure in which emmetropia is the goal, with the implantation of extended depth-of-focus or multifocal intraocular lenses (IOLs) being the commonly selected option to restore vision beyond the far distance. The selection criteria for implanting these lenses can differ from those for monofocal IOLs and even between technologies, as eye characteristics can affect postoperative visual performance. Corneal astigmatism is an eye characteristic that can affect visual performance differently, depending on the implanted IOL. The magnitude of corneal astigmatism, the tolerance of the IOL to this astigmatism, economic aspects, comorbidities, and the efficacy of astigmatism treatment are factors that can make surgeons' doubt as to what astigmatism treatment should be applied to each patient. This review aims to summarize the current evidence related to low astigmatism tolerance in presbyopia-correcting lenses, the efficacy achieved through corneal incisions, and their comparison with the implantation of toric IOLs.

Analysis of Daily Visual Habits in a Presbyopic Population.

Purpose: To evaluate and report the visual habits and requirements of a sample of presbyopic patients using an advanced sensor. Methods: Transversal study collecting clinical data from 40 presbyopes candidates for presbyopia-correction intraocular lens (IOL) implantation with mean age of 61.0 years (43-80 years). A complete ophthalmological examination was performed in all patients including visual, refractive, an ocular biometric analysis. Furthermore, patients were instructed about the use of the Vivior Monitor system (Vivior AG, Zürich, Switzerland), which consists of a series of sensors attached to the rim of the patient's glasses that capture information about the visual behavior of the patient. This device was worn for a period of 36 hours or more. The data collected were transferred to a database and analyzed. Results: Mean percentages of time dedicated to distance, intermediate, and near vision were 27.25 ± 11.93% (5-65%), 30.23 ± 9.36% (12-50%), and 42.53 ± 14.96% (13-78%), respectively. Mean percentages of time performing activities under photopic, mesopic, and scotopic conditions were 37.08 ± 23.20% (5-87%), 33.65 ± 13.84% (6-67%), and 29.28 ± 17.03% (4-65%). The percentage of time with digital screens ranged from 2% to 48%. Age was significantly correlated with the percentage of time dedicated to distance vision (r = 0.317, p=0.047) and to activities performed under photopic conditions (r = -0.344, p=0.030). Conclusions: Distance and illumination conditions used to perform different daily life visual activities vary significantly among presbyopes, with a trend to the dedication of more time to intermediate and near visual activities performed under photopic and mesopic conditions. Data interpretation should be done with care until a proper validation of the device used.

ESCRS Clinical Trends Survey 2016-2021: 6-year assessment of practice patterns among society delegates.

PURPOSE: To evaluate clinical opinions and practice patterns of delegates to the ESCRS. SETTING: Clinical Trends Surveys were administered during annual ESCRS congresses held between 2016 and 2021, and data collected online and in-person. DESIGN: Survey questions addressed several specialty areas, including cataract surgery, presbyopia-correcting and toric intraocular lenses (IOLs), ocular surface disease, and glaucoma. METHODS: Survey results were compared and analyzed across 6 years. 4 main profile questions were used for cross-tabulation analyses of questions pertaining to refractive surgery-practice location, years in practice, primary surgery setting, and average annual volume of cataract surgery. RESULTS: The highest number of responses (3019) was collected in 2019, with the lowest (569) received in 2020. The use of presbyopia-correcting and toric IOLs has increased significantly from 2016 to 2021, with certain respondent segments using them more frequently than others. Although optical biometry remains the preferred method for obtaining preoperative measurements, the use of tomography (Scheimpflug) has significantly increased. In 2021, 61.1% and 44.9% of respondents always performed preoperative checks of the ocular surface before refractive and cataract surgery, respectively. The number of respondents who perform glaucoma surgery has significantly decreased over the years, with an increasing number of delegates reporting having only a medical glaucoma practice. On average, 5.4% of patients with cataract and glaucoma underwent combined minimally invasive glaucoma surgery and cataract procedures in 2021. CONCLUSIONS: Evaluation of the Clinical Trends Survey data provides valuable insights into the shifting practice patterns and clinical opinions of ESCRS delegates.

3D Modeling of the Crystalline Lens Complex under Pseudoexfoliation.

Pseudoexfoliation, one of the most frequent crystalline lens complex disorders, is prevalent in up to 30% of individuals older than 60 years old. This disease can lead to severe conditions, such as subluxation or dislocation of the lens, due to the weakening of the zonules. The goal for the present study was to understand the relevant biomechanical features that can lead to the worsening of an individual's visual capacity under pseudoexfoliation. To this end, finite element models based on a 62-year-old lens complex were developed, composed by the capsular bag, cortex, nucleus, anterior, equatorial, and posterior zonular fibers. Healthy and pseudoexfoliative conditions were simulated, varying the location of the zonulopathy (inferior/superior) and the degenerated layer. The accommodative capacity of the models with inferior dialysis of the zonular fibers was, on average, 4.7% greater than for the cases with superior dialysis. If the three sets of zonules were disrupted, this discrepancy increased to 14.9%. The present work provides relevant data to be further analyzed in clinical scenarios, as these models (and their future extension to a wider age range) can help in identifying the most influential regions for the reduction of the visual capacity of the lens.

Intraocular lens power calculation with ray tracing based on AS-OCT and adjusted axial length after myopic excimer laser surgery.

PURPOSE: To report the results of intraocular lens (IOL) power calculation by ray tracing in eyes with previous myopic excimer laser surgery. SETTING: G.B. Bietti Foundation I.R.C.C.S., Rome, Italy. DESIGN: Retrospective interventional case series. METHODS: A series of consecutive patients undergoing phacoemulsification and IOL implantation after myopic excimer laser was investigated. IOL power was calculated using ray-tracing software available on the anterior segment optical coherence tomographer MS-39. Axial length (AL) was measured by optical biometry, and 4 values were investigated: (1) that from the printout, (2) the modified Wang/Koch formula, and (3) the polynomial equation for the Holladay 1 and (4) for the Holladay 2 formulas. The mean prediction error (PE), median absolute error (MedAE), and percentage of eyes with a PE within ±0.50 diopters (D) were reported. RESULTS: The study enrolled 39 eyes. Entering the original AL into ray tracing led to a mean hyperopic PE (+0.56 ±0.54 D), whereas with the Wang/Koch formula, a mean myopic PE (-0.41 ±0.53 D) was obtained. The Holladay 1 and 2 polynomial equations lead to the lowest PEs (-0.10 ±0.49 D and +0.08 ±0.49 D, respectively), lowest MedAE (0.37 D and 0.25 D), and highest percentages of eyes with a PE within ±0.50 D (71.79% and 76.92%). Calculations based on the Holladay 2 polynomial equation showed a statistically significant difference compared with other methods used (including Barrett-True K formula), with the only exception of the Holladay 1 polynomial equation. CONCLUSIONS: IOL power was accurately calculated by ray tracing with adjusted AL according to the Holladay 2 polynomial equation.

Comparison of refractive and visual outcomes of 3 presbyopia-correcting intraocular lenses.

PURPOSE: To evaluate and compare the clinical outcomes after cataract surgery with implantation of 3 types of trifocal diffractive intraocular lenses (IOLs). SETTING: Hospital da Luz, Lisbon, Portugal. DESIGN: Prospective comparative case series. METHODS: Patients undergoing phacoemulsification cataract surgery with implantation of 1 of the 3 trifocal IOLs were enrolled: TECNIS Synergy (Synergy group, 30 patients), Acrysof PanOptix (PanOptix group, 30 patients), and POD F (Finevision group, 30 patients). The outcomes of distance, intermediate, and near visual acuity (VA), refraction, defocus curve, photic phenomena, and spectacle independence were evaluated at the 3-month follow-up. RESULTS: 180 eyes of 90 patients were enrolled. No statistically significant differences were found between groups in monocular distance-corrected intermediate (Synergy group 0.04 ± 0.11, PanOptix group 0.05 ± 0.09, and Finevision group 0.08 ± 0.10; P = .107) and near VA (0.01 ± 0.08, 0.01 ± 0.06, and 0.04 ± 0.10, respectively; P = .186). Similarly, no statistically significant differences among groups were found in binocular uncorrected distance (P = .572), near (P = .929), and intermediate VA (P = .327). By contrast, statistically significant differences between groups were found in the visual acuity for the vergence demands of -0.50, -1.00, -2.00, -3.50, and -4.00 diopters (P ≤ .045). No statistically significant differences among groups were found in the frequency, severity, and bothersomeness of different disturbing visual symptoms, including glare and halos (P ≥ .129). More than 87 (96%) of patients in all groups did not require the use of spectacles at any distance postoperatively. CONCLUSIONS: The 3 trifocal IOLs evaluated provided an effective visual rehabilitation with minimal incidence of photic phenomena. A trend to obtain a wider range of functional focus was observed with the TECNIS Synergy IOL.

Visual outcomes and patient satisfaction after implantation of a presbyopia-correcting intraocular lens that combines extended depth-of-focus and multifocal profiles.

PURPOSE: To evaluate clinical outcomes delivered by a new hybrid presbyopia-correcting intraocular lens (IOL): TECNIS Synergy ZFR00V IOL model (Johnson & Johnson Vision). SETTING: Hospital da Luz Lisboa, Lisbon, Portugal. DESIGN: Prospective observational study. METHODS: Patients undergoing bilateral IOL implantation were included. Visual acuity (VA) was measured for far distance, intermediate (66 cm), and near (40 cm) vision under both photopic and mesopic conditions. In addition, at the 3-month follow-up visit, the defocus curve was obtained for binocular vision, and questionnaires were administered to measure spectacle independence and level of satisfaction ( quality of vision and Catquest-SF9) with the surgical outcomes. RESULTS: 54 eyes of 27 patients were included. At the 3-month follow-up, under photopic conditions, VA values were as follows: corrected distance VA (CDVA) = -0.02 ± 0.07, distance-corrected intermediate VA = 0.03 ± 0.11, and distance-corrected near VA (DCNVA) = 0.00 ± 0.08, whereas under mesopic conditions, VA values were as follows: CDVA = -0.01 ± 0.05 and DCNVA = 0.07 ± 0.09. The binocular defocus curve revealed that mean VA was better than 0.30 logMAR within the +1.00 to -4.00 diopters (D) interval, and better than 0.10 logMAR between +0.50 and -3.00 D. All patients achieved distance vision spectacle freedom, whereas 3.7% of them said they used them in certain intermediate or near vision situations. As much as 88% of the patients reported being fairly satisfied or very satisfied. CONCLUSIONS: The TECNIS Synergy ZFR00V IOL model used for cataract surgery is capable of restoring visual function while providing very good intermediate and near vision, under both photopic and mesopic conditions, resulting in a high level of patient satisfaction.

Evaluation of posterior and total corneal astigmatism with colour-LED topography.

PURPOSE: To characterise the posterior and total corneal astigmatism using colour point-source light-emitting diodes (LED) topography. METHODS: In a prospective case series 400 eyes from 400 patients were evaluated by colour-LED topography. Only eyes with normal topographies were considered. The following parameters were studied: magnitude and distribution of SimK and posterior corneal astigmatism, correlation between SimK and posterior corneal astigmatism, and differences in magnitude and axis between total and anterior corneal astigmatism. RESULTS: The mean SimK corneal astigmatism was 1.21 ± 0.94 D. The mean posterior corneal astigmatism was 0.37 ± 0.24 D. Posterior astigmatism was vertically oriented in 68% of eyes. Twenty-two percent of eyes showed a posterior corneal astigmatism ≥ 0.50 D. The correlation coefficients between SimK and posterior corneal astigmatism were: r2 = 0.066; p = 0.371 in WTR eyes, r2 = 0.112; p = 0.173 in ATR eyes and r2 = -0.019; p = 0.879 in oblique eyes. A difference between SimK and total corneal astigmatism ≥ 0.50 D was found in 7% of eyes. A difference in axis between SimK and total corneal astigmatism ≥ 10° was found in 24% of eyes. CONCLUSIONS: The percentage of eyes with posterior corneal astigmatism ≥ 0.50 D and the differences between anterior and total corneal astigmatism were higher than those previously reported in the literature. Therefore, this study supports the consideration of total corneal astigmatism magnitude and axis is mandatory for a precise surgical correction of astigmatism.

Comparison of clinical outcomes of 3 trifocal IOLs.

PURPOSE: To compare the clinical outcomes obtained after implantation of 1 of 3 models of diffractive trifocal IOLs. SETTING: Hospital da Luz, Lisbon, Portugal. DESIGN: Prospective randomized comparative study. METHODS: Patients undergoing cataract surgery with bilateral implantation of 1 of 3 models of diffractive trifocal IOLs were enrolled. The IOL models implanted were the FineVision POD F, RayOne Trifocal, or the AcrySof IQ PanOptix IOL (30 eyes of 15 patients in each group). Visual acuity (VA), refraction, defocus curve, and contrast sensitivity outcomes were evaluated during a 3-month follow-up. Furthermore, the Quality of Vision questionnaire (QoV) was used to evaluate the frequency, severity, and discomfort of different visual symptoms. RESULTS: A total of 90 eyes of 45 patients were included. No statistically significant differences were found between groups in distance, intermediate, and near VA (P ≥ .112) and postoperative refraction (P ≥ .059). Postoperative binocular uncorrected intermediate VA of 0.10 logarithm of the minimum angle of resolution (logMAR) or better was found in 14 (93.33%) patients in the 3 groups. Postoperative binocular uncorrected near VA of 0.10 logMAR or better was found in 13 (86.67%), 14 (93.33%), and 13 (86.67%) patients in the POD F, RayOne, and PanOptix IOLs groups, respectively. No statistically significant differences were found between groups in scotopic contrast sensitivity with and without glare and in the QoV scores (P ≥ .057), except for the difference between the POD F and RayOne IOLs groups in depth perception severity, which was less in the RayOne IOL group (P = .019). CONCLUSIONS: The 3 trifocal IOLs evaluated provided a complete visual restoration with good visual quality outcomes.

How Can We Improve Toric Intraocular Lens Calculation Methods? Current Insights.

In this paper, we review current strategies for calculating toric intraocular lenses (IOLs). We discuss the prevalence and clinical relevance of astigmatism and the assessment of toric IOL candidates. We detail recommendations for evaluating astigmatism and current biometry and IOL power calculation techniques. Finally, error sources and results of current toric IOL calculators are discussed.

Comparison of visual and refractive outcomes of 2 trifocal intraocular lenses.

PURPOSE: To compare clinical outcomes after cataract surgery and bilateral implantation of 2 diffractive trifocal toric intraocular lenses (IOLs). SETTING: Hospital da Luz, Lisbon, Portugal. DESIGN: Double-arm, randomized, prospective case series. METHODS: A total of 60 patients were randomly allocated to receive bilateral implantation of either the FineVision Pod FT toric IOL (PhysIOL) or the AcrySof IQ PanOptix toric IOL (Alcon). Visual and refractive outcomes, contrast sensitivity, IOL misalignment, and quality of vision outcomes (QoV questionnaire) were evaluated at 3 months postoperatively. Surgically induced astigmatic changes were evaluated by vector analysis. RESULTS: Each group (FineVision toric and AcrySof IQ PanOptix toric) comprised 30 patients (60 eyes). No significant differences between groups were found regarding uncorrected and corrected distance and near visual outcomes (P ≥ .333). Mean postoperative distance-corrected intermediate visual acuity at 60 cm was 0.04 ± 0.09 logarithm of the minimum angle of resolution (logMAR) and 0.09 ± 0.11 logMAR in the PanOptix and Pod FT group, respectively (P = .032). Mean IOL axis misalignment was 1.59 degrees ± 2.15 degrees (PanOptix group) and 1.89 degrees ± 3.31 degrees (Pod FT group) (P = .821). Mean magnitude of error of astigmatic correction was -0.09 diopters (D) and -0.11 D in the PanOptix group and Pod FT group, respectively (P = .333). Contrast sensitivity, QoV scores for the presence of photic phenomena, and the level of spectacle independence were similar in both groups (P > .05). CONCLUSIONS: Both trifocal toric IOLs allowed complete patient visual restoration, and good spectacle independence and good visual quality outcomes. The PanOptix IOL provided superior intermediate visual acuity for distances around 60 cm.