Search Results (78)

Ageing results in the progressive loss of near vision, known as presbyopia, which impacts individuals and society. Existing corrective methods offer only partial compensation and do not restore dynamic focusing at varying distances. This work presents a closed-loop correction system for presbyopia, employing biopotential signals from the ciliary muscle and an artificial neural network to predict the eye’s accommodative state in real time. Non-invasive contact lens electrodes collect biopotential data, which are preprocessed and classified using a multi-layer perceptron. The classifier output guides a control system that adjusts an external focus-tunable lens, enabling both accommodation and disaccommodation similar to a young eye. The system demonstrated an accuracy of 0.79, with F1-scores of 0.78 for prediction of accommodation and 0.77 for disaccommodation. Using the system in two presbyopic subjects, near visual acuity improved from 0.28 and 0.38 to 0.04 and −0.03 logMAR, while distance acuity remained stable. Despite challenges such as signal quality and individual variability, the findings demonstrate the feasibility of restoring near-natural accommodation in presbyopia using neuromuscular signals and adaptive lens control. Future research will focus on system validation, expanding the dataset, and pre-clinical testing in implantable devices. Full article

Background/Objectives: The aim of this study was to evaluate the correlation between the visual curve (ViC) and Area of the Curve (AoC) indices and the subjective perception of vision-related quality of life in patients who had undergone pseudophakic presbyopia correction. The central hypothesis was that AoC indices would show stronger correlations with vision-specific quality-of-life measures than single-point visual acuity (VA) assessments. Methods: A total of 100 patients who underwent bilateral pseudophakic presbyopia correction at the University Hospital of Alexandroupolis, Greece, were included in the study. Six months following surgery, visual acuity was assessed at nine distances using the DDART tool. The AoC was calculated using VA data from four, five, six, and nine distances, and further categorized into Near Vision AoC (AoCN) and Distance Vision AoC (AoCD). Participants also completed the NEI-VFQ-25 questionnaire to evaluate their subjective vision-related quality of life. Results: Statistically significant correlations were observed between AoC values and NEI-VFQ-25 total scores (r = 0.668–0.682, p < 0.001), near activity subscale scores (r = 0.656–0.686, p < 0.001), and distance activity subscale scores (r = 0.733–0.758, p < 0.001). In all analyses, the AoC indices derived from ViC demonstrated stronger correlations with quality-of-life scores than those observed with AoC-derived DCT and single VA measurements, even when the AoC was computed using only four measurement points. Conclusions: The AoC metric is a superior indicator of vision-specific quality of life compared to isolated VA measurements. AoC effectively captures the multifaceted nature of functional vision following presbyopia correction. Full article

Background/Objectives: Ocular wavefront aberrations are clinically relevant for optimizing vision correction and predicting surgical outcomes. This study aimed to establish normative reference ranges for a Korean population by quantifying wavefront aberrations using a Hartmann–Shack wavefront sensor and Zernike coefficients, and to assess correlations with age, sex, and spherical equivalent (SE). Methods: Wavefront aberrations were measured in 98 Koreans (196 eyes) using a Hartmann–Shack aberrometer without cycloplegia. Five repeated measurements per eye at a 6 mm pupil size were averaged. Parameters included Zernike coefficients (Z3–Z20), higher-order aberration (HOA) root mean square (RMS, Z6–Z20), and total RMS (Z3–Z20). Associations with age, sex, and SE were assessed using univariable and multivariable linear mixed-effects models. Second-order polynomial regression assessed nonlinear relationships. Interocular symmetry was evaluated using mirror-symmetry-adjusted Spearman’s correlation and intraclass correlation coefficients (ICCs). Results: Vertical coma (Z7, 0.208 ± 0.174 μm) and spherical aberration (Z12, 0.200 ± 0.161 μm) were the largest contributors to HOA RMS. Mean HOA RMS and total RMS were 0.51 ± 0.21 μm and 3.03 ± 2.51 μm, respectively. HOA RMS increased with age (β = 0.003 μm/year, p = 0.010), whereas total RMS decreased with SE (β = −0.678 μm/D, p < 0.001). Most Zernike coefficients showed positive interocular correlations, with ICCs of 0.75 for total RMS and 0.64 for HOA RMS. Conclusions: In normal Korean eyes, HOAs increased with age and exhibited significant interocular symmetry. Vertical coma and spherical aberration were predominant components. While the pattern was similar to that in Western populations, the absolute values were greater. These normative values may aid future wavefront-guided refractive surgery and presbyopia correction procedures. Full article

Background: Intraocular lens (IOL) alignment is crucial for optimal performance in presbyopia-correcting designs. The aim was to report a case of a patient with a high angle kappa implanted with the continuous transitional focus (CTF) Precizon Prebyopic NVA IOL. Case presentation: A 51-year-old patient presenting large angle kappa values (0.6/0.8 mm) was implanted with the Precizon Prebyopic NVA IOL and followed-up 1 and 10 months post-surgery. This IOL is designed with a butterfly-shaped central area that allows the orientation of the lens so that the visual axis passes through the wider diameter of the optic zone. Postoperative refraction was −0.25D of cyl at 80° for the right eye and +0.25D −0.50D cyl at 170°. Corrected distance visual acuity (CDVA) at the last visit was −0.1 logMAR monocularly and −0.2 logMAR binocularly. Binocular uncorrected distance (UDVA), intermediate (UIVA) and near visual acuities (UNVA) were −0.1, 0.1 and 0.1 logMAR, respectively. The corrected binocular defocus curve exhibited outstanding vision at the 0.00D defocus level and showed a continuous range of functional vision from distance to near. Overall excellent satisfaction was reported, along with low levels of photopic phenomena. Conclusions: Precizon Presbyopic NVA IOL provided satisfactory vision and low levels of photic phenomena in a high angle kappa patient who would potentially be excluded from presbyopia-correcting IOL implantation. Full article

Presbyopia is a ubiquitous age-related condition characterized by reduced near focusing ability due to lenticular stiffening. Pharmacologic agents such as pilocarpine have re-emerged as a less-invasive treatment option by inducing miosis and thereby enhancing depth of focus. However, the optimal pharmacologically induced pupil size that balances improved near vision with sufficient retinal illuminance remains undetermined. In this work, we present for the first time a direct integration of advanced theoretical modeling with a systematic synthesis of clinical trial outcomes to define the optimal target pupil size for pharmacologic presbyopia correction. We modeled visual performance using the Visual Strehl Ratio of the Optical Transfer Function (VSOTF) and convolved images of optotypes across a range of pupil diameters from 1.5 mm to 3.5 mm. This combined optical–clinical approach allowed us to quantitatively compare modeled image quality and depth of focus predictions with real-world clinical efficacy data from pilocarpine-based interventions. Simulations showed that smaller pupil sizes (1.5–2.5 mm) significantly extended depth of focus compared to standard multifocal optics while maintaining image quality within acceptable limits. These findings align with clinical trials of pilocarpine formulations, which commonly achieve post-treatment pupil diameters in the 2.0–2.5 mm range and are associated with clinically meaningful gains in near vision. Our analysis uniquely demonstrates that these clinically achieved pupil sizes closely match the theoretically optimal 2.0–3.0 mm range identified in our modeling, strengthening the evidence base for drug design and patient selection. These results reinforce the role of pharmacologically controlled pupil size as a central target in presbyopia management. By explicitly linking predictive optical modeling with aggregated clinical outcomes, we introduce a novel framework to guide future pharmacologic development strategies and refine clinical counseling in the emerging era of presbyopia therapeutics. Full article

Background/Objectives: Age-related macular degeneration (AMD) is a leading cause of visual impairment in older adults and often coexists with cataracts. The indication of presbyopia-correcting intraocular lenses (IOLs) in these patients remains controversial. This study aimed to evaluate the clinical performance of a non-diffractive extended depth-of-focus (EDOF) IOL (LuxSmart™) compared to a monofocal plus IOL (Tecnis Eyhance™) in cataract patients with early-stage dry AMD. Methods: In this prospective observational study, 41 patients with early-stage AMD underwent bilateral cataract surgery with either LuxSmart™ or Tecnis Eyhance™ IOL implantation, targeting postoperative emmetropia. The eye selected for analysis was the first eye scheduled for surgery. Preoperative and postoperative evaluations included high and low-contrast distance visual acuity, intermediate and near visual acuity, defocus curves, ocular light scatter (halometry), and quality of life assessment (NEI VFQ-25). Postoperative biometric accuracy and refractive outcomes were also analyzed. Results: Both IOLs showed high refractive accuracy, with 100% of eyes within ±0.50 D of target. Postoperative uncorrected distance visual acuity was 0.10 ± 0.06 LogMAR for Eyhance and 0.07 ± 0.02 for LuxSmart (p = 0.06). Low contrast VA at 20% was 0.22 ± 0.11 (Eyhance) and 0.26 ± 0.16 (LuxSmart) (p = 0.49). Depth of focus was approximately 1.75 D for both lenses. Light scatter (LDI) improved postoperatively in both groups with no significant differences (p = 0.54). VFQ-25 scores showed improvement in daily activities, though no changes were observed in driving or mental health domains. Conclusions: Both lenses are safe and effective options for early AMD patients undergoing cataract surgery, providing good functional vision at multiple distances Full article

This study describes and validates a novel method for assessing anterior crystalline lens curvature along vertical and horizontal meridians using radial measurements derived from Scheimpflug imaging. The aim was to evaluate whether pupil diameter (PD), anterior lens curvature, and anterior chamber depth (ACD) change during accommodation and whether these changes are age-dependent. A cross-sectional study was conducted on 104 right eyes from healthy participants aged 21–62 years. Sixteen radial images per eye were acquired using the Galilei Dual Scheimpflug Placido Disk Topographer under four accommodative demands (0, 1, 3, and 5 dioptres (D)). Custom software analysed lens curvature by calculating eccentricity in both meridians. Participants were analysed as a total group and by age subgroups. Accommodative amplitude and monocular accommodative facility were inversely correlated with age. Both PD and ACD significantly decreased with higher accommodative demands and age. Relative eccentricity decreased under accommodation, indicating increased lens curvature, especially in younger participants. Significant curvature changes were detected in the horizontal meridian only, although no statistically significant differences between meridians were found overall. The vertical meridian showed slightly higher eccentricity values, suggesting that it remained less curved. By enabling detailed, meridionally stratified in vivo assessment of anterior lens curvature, this novel method provides a valuable non-invasive approach for characterizing age-related biomechanical changes during accommodation. The resulting insights enhance our understanding of presbyopia progression, particularly regarding the spatial remodelling of the anterior lens surface. Full article

Background/Objectives: A new, purely refractive extended depth-of-focus (EDOF) intraocular lens (IOL) was designed with a continuous change in power to bridge the gap between monofocal and multifocal IOLs. This study aimed to evaluate the real-world clinical outcomes of the new EDOF IOL compared with those of the enhanced monofocal IOL. Methods: A retrospective analysis was conducted on 100 eyes from 50 patients undergoing bilateral cataract surgery with either the PureSee™ EDOF (ZEN00V) or Eyhance™ (ICB00) monofocal IOL at a single institution. Visual acuity, defocus curves, contrast sensitivity, and patient-reported outcomes were evaluated three months postoperatively. Results: The ZEN00V group demonstrated superior uncorrected intermediate (0.11 ± 0.08 vs. 0.17 ± 0.11 logMAR, p = 0.006) and near visual acuity (0.25 ± 0.08 vs. 0.31 ± 0.13 logMAR, p = 0.023) compared to the ICB00 group, with comparable distance visual acuity. Both groups exhibited comparable defocus curves and contrast sensitivity. While photic phenomena were more frequent in the ZEN00V group, spectacle dependence was significantly lower for near vision (36% vs. 80%, p = 0.002) and comparable for intermediate and far vision. Conclusions: The PureSee™ EDOF IOL demonstrated enhanced intermediate and near vision with minimal compromise to distance vision while maintaining high contrast sensitivity. It also offered significant spectacle independence and patient satisfaction, making it a promising option for presbyopia correction. Full article

Background: Personalized precision medicine has become a prevailing trend and applies to the selection of intraocular lenses (IOLs) for cataract surgery based on the unique corneal morphology of each person. The choice of presbyopia-correcting IOLs for post-laser-assisted in situ keratomileusis (LASIK) cataract surgery is a significant concern. However, few direct comparison studies exist between eyes with and without LASIK history. We analyzed the performance of extended depth of focus (EDOF) IOL implantation in these two groups. Methods: In this retrospective single-center study, we included patients with or without previous LASIK who underwent cataract surgery and EDOF Symfony IOL implantation, with ≥1 follow up. All patients underwent optical biometry using the IOLMaster. IOL power was calculated using the Sanders Retzslaff Kraff/theoretical and Haigis-L formulas for patients without and with LASIK, respectively. Uncorrected distance visual acuity (UDVA), uncorrected near visual acuity (UNVA), refraction, and corneal tomography were recorded. The prediction error was the absolute difference between the postoperative sphere and target refraction. The right eyes of patients who met the inclusion criteria were selected for analysis. Results: Among the 321 recruited eyes, 18 underwent previous LASIK. After 1:3 age/sex matching, 17 LASIK and 49 non-LASIK eyes from 66 patients were analyzed. No significant preoperative differences existed in target refraction, spherical equivalent, or best-corrected visual acuity. All surgical procedures were uneventful. LASIK exhibited non-inferiority to non-LASIK for predictive refraction error and UNVA. An age/sex-matched regression analysis indicated no UDVA superiority between the two groups. Conclusions: Previous LASIK may have no discernible effect on the visual performance of presbyopia-correcting EDOF IOLs with respect to the absolute refractive error, UNVA, and UDVA. Longer follow-up and larger-scale studies are required to further validate these results. Full article

Background: The objective was to preliminarily evaluate the short-term clinical outcomes obtained in presbyopic patients with a novel, multifocal, customized corneo-scleral contact lens (CSCL). Methods: A total of 11 presbyopic subjects (age 45–80 years, corrected-distance visual acuity ≤ 0.1 LogMAR, near addition ≥ +1.00 D) were recruited and fitted with a multifocal corneo-scleral contact lens in this pilot study. Pre-fitting evaluations included stereopsis, contrast sensitivity (CS), and ocular aberrometry, with follow-up assessments conducted at 20 min and 1-month post-fitting. The defocus curve was also measured to assess visual performance across varying distances. Results: Twenty-two eyes from 11 participants (53.9 ± 4.7 years, 10 female) were included in this study. Significant changes were observed post-fitting for primary and secondary spherical aberration, coma, and stereopsis (p ≤ 0.033). No significant changes in Strehl ratio and total root mean square were detected (p ≥ 0.182). Binocular contrast sensitivity was better with spectacles than with the fitted CSCL at all frequencies (p ≤ 0.048), but the change in monocular did not reach statistical significance for 18 cycles per degree (p = 0.109). All patients and 90.9% of patients achieved a visual acuity of 0.0 LogMAR or better at distance and at intermediate, respectively, and 91.8% achieved 0.3 LogMAR or better for near vision. Conclusions: The customized CSCL evaluated provided functional recovery of visual quality across distances, with acceptable reductions of CS and stereopsis that are comparable to those reported for other multifocal contact lenses. Full article

Background/Objectives: To evaluate the efficacy and visual quality provided by the extended depth-of-focus AcrySof IQ Vivity lens (Alcon Laboratories, Inc., Fort Worth, TX, USA) in patients undergoing refractive lens exchange (RLE) surgery for presbyopia correction. Methods: This descriptive prospective single-arm clinical study included 30 patients (60 eyes) aged 49–69 years (mean 60.2) who underwent clear lens surgery for presbyopia correction. Postoperative 3-month assessments included uncorrected distance visual acuity (UDVA), uncorrected intermediate visual acuity (UIVA), uncorrected near visual acuity (UNVA), distance-corrected intermediate visual acuity (DCIVA), and distance-corrected near visual acuity (DCNVA) measurements. Patient satisfaction and visual disturbances were evaluated using a standardized questionnaire. Results: Postoperative binocular visual acuity results were as follows: UDVA, 0.00 ± 0.06 logMAR; UIVA 0.08 ± 0.07 logMAR; and UNVA, 0.18 ± 0.10 logMAR. Refractive outcomes showed mean spherical equivalent values of −0.15 D ± 0.28 diopters (D) for the right eye and −0.18 D ± 0.30 D for the left eye postoperatively. Most patients (93.2%) were satisfied or very satisfied with the surgery, and 63.3% never needed glasses at any distance postoperatively. Mild and non-disabling photic phenomena were reported by 23% of patients for halos and 30% for glares. Conclusions: The study IOL provides excellent visual acuity for far and intermediate distances, as well as functional near vision under photopic conditions, with high levels of patient satisfaction and minimal visual disturbances. This lens is a promising option for non-cataract patients undergoing RLE for presbyopia correction. Full article

The measurement of electrical potentials in the human body is becoming increasingly important in healthcare as a valuable diagnostic parameter. In ophthalmology, while these signals are primarily used to assess retinal function, other applications, such as recording accommodation-related biopotentials from the ciliary muscle, remain poorly understood. Here, we present the development and evaluation of a novel implantable ring electrode for recording biopotentials from the ciliary muscle. Inspired by capsular tension rings, the electrode was fabricated using laser cutting, wiring, and physical vapor deposition coating. The constant impedance and weight over a simulated aging period of 391 days, demonstrated the electrode’s stability. In vivo testing in non-human primates further validated the electrode’s surgical handling and long-term stability, with no delamination or tissue ingrowth after 100 days of implantation. Recorded biopotentials from the ciliary muscle (up to 700 µV) exceeded amplitudes reported in the literature. While the results are promising, further research is needed to investigate the signal quality and origin as well as the correlation between these signals and ciliary muscle activity. Ultimately, this electrode will be used in an implanted device to record ciliary muscle biopotentials to control an artificial lens designed to restore accommodation in individuals with presbyopia. Full article

Small-incision lenticule extraction (SMILE) is a safe and effective procedure to correct myopia and myopic astigmatism. The corneal stromal lenticules extracted from SMILE surgery have good light transmission, mechanical properties, and biocompatibility, which are suitable for the treatment of a variety of corneal diseases and can solve the problem of donor cornea shortage. At present, no single method of preserving corneal stromal lenticules has been universally accepted as ideal, as the preservation of tissue integrity, optical transmittance, cellular viability, and the potential for long-term storage remain key challenges. Current approaches include short-term preservation methods such as the use of dehydrating agents and Optisol GS, and long-term preservation strategies such as cryopreservation, hydrogel nutrient capsules, and silicone oil. Standardized storage methods can improve the use of SMILE-derived lenticules as a substitute for donor corneal tissue in clinical settings. The reuse of corneal stromal lenticules is a highly regarded research area, especially in hyperopia, presbyopia, keratoconus, and some corneal ulcerative diseases, providing new possibilities for addressing corneal tissue shortage and improving surgical outcomes. Here, we review various preservation methods and clinical applications of SMILE-extracted lenticules, highlighting their potential in addressing corneal tissue shortages and the treatment of a variety of corneal diseases. Full article

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. Full article

Objectives: To investigate the dynamics of accommodation during and immediately after a sustained reading task on a digital device across various age groups under monocular and binocular conditions. Methods: Seventeen subjects were selected and divided into three age groups: young adults (n = 4, age: 21.3 ± 3.2 years), adults (n = 4, age: 34 ± 3.56 years), and incipient presbyopes (n = 9, age: 45 ± 3.61 years). Dynamic accommodation and disaccommodation were objectively measured using the WAM-5500 open-view autorefractor during 2 min of distance fixation (Maltese cross at 6 m), 5 min of sustained near reading on a teleprompter app at the nearest readable distance, and 2 min of distance vision. Six sequential temporal landmarks were identified. Quantitative metrics for accommodation lag (AL), slope of slow accommodation (SSA), slope of slow disaccommodation (SSD), peak velocity of accommodation (PVA) and peak velocity of disaccommodation (PVD) were obtained as absolute values of spherical equivalent refractive (SER) change. Results: SSA, SSD, and AL were significantly and positively correlated with age (ρ = 0.75, 0.73, 0.51, respectively; p ≤ 0.038). For subjects under 45 years of age SSA and SSD increased quadratically with age, while for those above 45 years, both SSA and SSD decreased linearly. Linear regression of PVA and PVD with age indicated that the disaccommodation mechanism is faster than accommodation (slope = –0.15 and –0.23, respectively). PVA was significantly faster under monocular than binocular conditions (p = 0.124). Conclusions: Incipient presbyopes demonstrate a complex response in both accommodation and disaccommodation. The accommodation system responds quickly, but there is also a slower response that can provide up to an additional 1D of accommodative response during sustained near reading tasks. It is hypothesized that the crystalline lens exhibits hysteresis in returning to its unaccommodated state, due to its viscoelastic properties, which means it takes time to relax. Full article