Calculation of Equivalent and Toric Power in AddOn Lenses Based on a Monte Carlo Simulation.

INTRODUCTION: Additional lenses implanted in the ciliary sulcus (AddOn) are one option for permanent correction of refractive error or generate pseudoaccommodation in the pseudophakic eye. The purpose of this paper was to model the power and magnification behaviour of toric AddOn and to show the effect sizes with a Monte Carlo simulation. METHODS: Anonymized data of a cataractous population uploaded for formula constant optimization were extracted from the IOLCon platform. After filtering out data with refractive spherical equivalent (RSEQ) between -0.75 and 0.25 dpt and refractive cylinder (RCYL) lower than 0.75, for each of the N = 6,588 records, a toric AddOn was calculated which transfers the refraction error from spectacle plane to AddOn plane using a matrix-based calculation strategy based on linear Gaussian optics. The equivalent (AddOnEQ) and toric (AddOnCYL) power of the AddOn and the overall lateral magnification change and meridional magnification were derived for the situations before and after AddOn implantation, and a linear modelling was fitted for all 4 parameters. RESULTS: RSEQ is the dominant effect size in the prediction of AddOnEQ and overall change in magnification (ΔM), whereas the lens position (LP), corneal thickness (CCT), and mean corneal radius (CPa) play a minor role. In a simplified model, AddOnEQ can be estimated by 0.0179 + 1.4104 RSEQ. RCYL and corneal radius difference (CPad) are the dominant effect sizes in the prediction of AddOnCYL and the change in meridional magnification (ΔMmer), whereas LP, CCT, CPa, and RSEQ play a minor role. In a simplified model, AddOnCYL can be predicted by -0.0005 + 0.0328 CPad + 1.4087 RCYL. Myopic eyes gain in overall magnification, whereas in hyperopic eyes, we observe a loss. Meridional distortion could be in general reduced to 35% on average with a toric AddOn. CONCLUSION: Our simulation shows that with a linear model, the equivalent and toric AddOn power, as well as overall change in magnification, meridional distortion before and after AddOn implantation, and the reduction in meridional distortion, can be easily predicted from the biometric data in pseudophakic eyes with moderate refractive error.

Calculation of ocular magnification in phakic and pseudophakic eyes based on anterior segment OCT data.

PURPOSE: The purpose of this study is to develop a straightforward mathematical concept for determination of object to image magnification in both phakic and pseudophakic eyes, based on biometric measures, refractometry and data from an anterior segment optical coherence tomography (OCT). METHODS: We have developed a strategy for calculating ocular magnification based on axial length measurement, phakic anterior chamber and lens thickness, keratometry and crystalline lens front and back surface curvatures for the phakic eye, and axial length measurement, anterior chamber and lens thickness, keratometry and intraocular lens power, refractive index and shape factor for the pseudophakic eye. Comparing the magnification of both eyes of one individual yields aniseikonia, while comparing the preoperative and postoperative situation of one eye provides the gain or loss in ocular magnification. The applicability of this strategy is shown using a clinical example and a small case series in 78 eyes of 39 patients before and after cataract surgery. RESULTS: For the phakic eye, the refractive index of the crystalline lens was adjusted to balance the optical system. The pseudophakic eye is fully determined and we proposed three strategies for considering a potential mismatch of the data: (A) with spherical equivalent refraction, (B) with intraocular lens power and (C) with the shape factor of the lens. Magnification in the phakic eye was -0.00319 ± 0.00014 and with (A) was -0.00327 ± 0.00013, with (B) was -0.00323 ± 0.00014 and with (C) was -0.00326 ± 0.00013. With A/B/C, the magnification of the pseudophakic eye was on average 2.52 ± 2.83%/1.31 ± 2.84%/2.14 ± 2.80% larger compared with the phakic eye. Magnification changes were within a range of ±10%. CONCLUSIONS: On average, ocular magnification does not change greatly after cataract surgery with implantation of an artificial lens, but in some cases, the change could be up to ±10%. If the changes are not consistent between the left and right eyes, then this could lead to post-cataract aniseikonia.

Ab interno implantation of glaucoma drainage devices tubes in the posterior chamber.

BACKGROUND: Glaucoma drainage device (GDD) implantation in the anterior chamber are associated with corneal complications. We describe a novel technique to implant GDD tubes in the posterior chamber of pseudophakic eyes. METHODS: Ten patients with glaucoma who required GDD tube implantation were included. RESULTS: The new technique begins with the passage of one of two straight needles existing at each end of a 10-0 Polypropylene suture through the GDD tube. A 23-gauge needle then is inserted at an angle 180° away and passed from the anterior to the posterior chamber and finally through the sclera. The two suture straight needles from the 10-0 Polypropylene suture are positioned in the lumen of the 23-gauge needle. The 23-gauge needle is then extracted from the eye by passing the 2 needles through the lumen. The suture remains inside the posterior chamber, and the tube is inserted into the posterior chamber by pulling on the suture from the other side. No intra-operative complications were found such as bleeding, vitreous tube placement, bent tubes, etc. CONCLUSIONS: This surgical procedure to implant a tube into the posterior chamber of the pseudophakic eyes is uncomplicated and facilitates the insertion of the flexible tube into the posterior chamber. This eliminates the tendency of the tube to enter the vitreous as the tube is always placed in the posterior chamber away from the cornea. TRIAL REGISTRATION: Current Controlled Trials ISRCTN14276553 (31th May, 2019) Retrospectively registered.

Based on the Real-Life Data of Türkiye; Comparison of Anatomical and Functional Outcomes of Phakic and Pseudophakic Patients in Wet Type Age-Related Macular Degeneration.

Objectives: The aim of the study was comparison of wet-type age-related macular degeneration in phakic and pseudophakic patients in terms of anatomical and functional success based on the real-life data of Türkiye. Methods: The multicenter retrospective real-life study data of the. retinal study group were used in this study. Among 867 eyes of 867 patients were included in the study. Patients were divided into two groups according to the status of the lens; phakic group and pseudophakic group. The follow-up period of the two groups, the number of injections at the 1st, 2nd, and 3rd years, and changes in the central macular thickness (CMT, µ) and visual acuity (VA, logMAR) of the patients at the beginning, 6th, 12th, 24th, and 36th months were examined. Results: In our study, the number of injections in the 1st, 2nd, and 3rd years, respectively, was 4.2±2.0, 1.8±1.9, and 1.0±1.7 in the phakic group, and 3.9±2.0, 1.7±1.9, and 0.8±1.4 in the pseudophakic group. When the two groups were compared in terms of the number of injections, there was a statistically significant difference in the 1st year, but there was no significant difference in the 2nd and 3rd years (p=0.001, p=0.350, and p=0.288, respectively). There was no statistically significant difference between the groups in terms of CMT in the baseline, 6th, 12th, 24th, and 36th months (p=0.991, p=0.327, p=0.652, p=0.599, and p=0.873, respectively). Although there was no difference in VA between groups at the beginning (p=0.052), the phakic group showed statistically better VA in controls at 3rd, 6th, 12th, 24th, and 36th months (p=0.001, p=0.001, p=0.000, p=0.000, and p=0.003, respectively). Conclusion: Differences in the number of injections and visual results between phakic and pseudophakic patients in wet type AMD may necessitate the creation of different treatment and follow-up protocols.

Efficacy of Intravitreal Injection of Filtered Modified Low-Dose Triamcinolone Acetonide and Ranibizumab on Pseudophakic Cystoid Macular Edema.

PURPOSE: To compare the visual and morphological effects between intravitreal injection of filtered modified 2 mg triamcinolone acetonide (TA) and 0. 5 mg ranibizumab in patients with pseudophakic cystoid macular edema (PCME). METHODS: A retrospective, interventional study was conducted from January 2015 to February 2020 involving patients with PCME after uneventful cataract surgery. A total of 25 patients (25 eyes) with PCME received an intravitreal injection of 0.22 µm filtered modified 2 mg TA, while 15 patients (15 eyes) received 0.5 mg ranibizumab injection. Central macular thickness (CMT), best-corrected visual acuity (BCVA), intraocular pressure (IOP), times of repeated injections, and other side effects were observed at 2 weeks, 1 month, 3 months, and 6 months after injection; then, the data were compared with preinjection information in each group and between the two groups. RESULTS: Both the TA and ranibizumab intravitreal injection can achieve improved BCVA and reduced CMT in patients with PCME (P < 0.05), with a trend toward greater improvement in the TA group, but the difference was only significant at 3 months (P < 0.05). IOP was in the normal range without any significant difference (P > 0.05). Thirty-three percent of patients in the ranibizumab group required repeated intravitreal injection compared to 4% in the TA group. Further stratified analysis showed that the better therapeutic effect of the TA group at 3 months after injection only existed in patients with diabetes mellitus (DM), while not in patients without DM. There was no repeat injection in the TA group and 12.5% in the ranibizumab group for patients without DM, while 16.7% in the TA group and 57.1% in the ranibizumab group required repeated injection for patients with DM, which had a significant difference (P < 0.05). CONCLUSION: Intravitreal injection of filtered modified 2 mg TA is safe, effective, and an inexpensive alternative to antivascular endothelial growth factor (anti-VEGF) agents for patients with PCME, especially for patients concurrently with DM. A large number of clinical randomized controlled studies along with long-term follow-up observations are needed.

Metric-Based Visual Acuity and Defocus Curve Simulation of Two Multifocal Intraocular Lens Models.

PURPOSE: To predict clinical defocus curve performance of the PanOptix intraocular lens (IOL) model TFNT00, a population-based image quality metric was applied to a pseudophakic eye model. METHODS: Visual acuity (VA) was simulated using a 2-surface reduced eye model. For each virtual eye, the derived corneal surface was combined with scaled IOL surface. Corneal power and aberration, anterior chamber depth, and pupil size were iterated using a Monte-Carlo approach. Image quality of the IOLs was assessed using the total aberration map to compute the amplitude point spread function. A diffraction-normalized light-in-the-bucket metric was calculated for each virtual eye for defocuses from -3.5 D to +1.0 D (step size 0.25 D) and transformed to VAs and defocus curves. Simulated VA for the ReSTOR +3.0 D lens was used to generate a calibration function by linear regression correlation of simulated data with clinical VA data. Simulated TFNT00 VA was then validated by comparing defocus curves to clinical TFNT00 data. RESULTS: From -3.5 D to +1.0 D, the simulated defocus curve was generally consistent with the defocus curve from the TFNT00 clinical trial. The mean absolute difference was 0.022 logMAR (~1 letter) for simulated VA versus clinical trial VA. CONCLUSION: IOL image quality can be assessed using a population-based virtual eye model to simulate VA and predict clinical performance. Computational modeling and simulation can be applied to future IOL development before clinical trials are conducted.

Comparison of Anatomical and Functional Outcomes of Intravitreal Dexamethasone Implant between Phakic and Pseudophakic Eyes with Diabetic Macular Edema.

PURPOSE: To compare the effectiveness of dexamethasone (DEX) intravitreal implants for the treatment of diabetic macular edema between phakic and pseudophakic eyes after a follow-up. METHODS: A total of 79 eyes in 79 patients with diabetic macular edema who were insufficiently responsive to the previous anti-vascular endothelial growth factor treatment and applied intravitreal DEX implant were included in this retrospective study. The patients were divided into two groups according to their type of lenses: pseudophakic (group 1) and phakic (group 2). Best-corrected visual acuity, intraocular pressure (IOP), retinal nerve fiber layer thickness, and central macular thickness changes in the two groups were compared. RESULTS: Group 1 comprised 42 eyes in 42 patients with a mean age of 64.02 ± 3.79 years, while group 2 comprised 37 eyes in 37 patients with a mean age of 64.19 ± 5.08 years. In both groups, best-corrected visual acuity improved significantly with a significant decrease in central macular thickness (p < 0.001). In both lens types, the IOP values decreased significantly on the first day but subsequently increased significantly compared to baseline from one week to six months. Increases in IOP values were significantly higher in group 1 at the first week, 1st month, and 6th month compared with group 2. During follow-up, the inferior quadrant retinal nerve fiber layer showed a significant decrease in both groups. CONCLUSIONS: In both phakic and pseudophakic eyes, intravitreal DEX implantation is an effective treatment method with low-risk complications. In our study, the pseudophakic group experienced a significantly earlier increase in IOP and at higher levels than did the phakic group. In light of these data, we suggest that in patients with pseudophakic eyes, follow-ups for IOP should be stricter and started earlier after intravitreal DEX treatment.

Evaluation of Visual Quality in Pseudophakic Eyes with Different Ocular Spherical Aberrations.

Purpose: To evaluate the effects of different residual total ocular spherical aberration (SA) on objective and subjective visual quality in pseudophakic eyes. Methods: This prospective consecutive study comprised 171 patients with age-related cataract and undergone unilateral uneventful phacoemulsification. All participants were divided into four groups based on residual ocular SA at 6 mm pupil: negative SA (≤-0.10 µm, group A), neutral SA (0.00 ± 0.05 µm, group B), slightly positive SA (0.10 ± 0.05 µm, group C), and more positive SA (0.20 µm, group D), respectively. Subjective visual acuity and contrast sensitivity, and objective optical quality and ocular aberrations were analyzed 3 months postoperatively. Results: There was no significant difference in baseline measurements across all groups. Postoperatively, no statistically significant differences were found in visual acuity between groups (P > .05), while differences reached statistical significance in mesopic contrast sensitivity at 12 and 18 cpd (P < .01). There were significant differences in ocular SA and higher-order aberrations at 6 mm pupil, as well as in optical quality parameters (P < .05). Group C showed a minimum value of objective scatter index (1.17 ± 0.55) but maximum values of modulation transfer function cutoff (31.94 ± 9.18) and optical quality value OV 100% (1.07 ± 0.31), indicating lower intraocular scattering and superior optical quality. Conclusions: This comprehensive evaluation is conducive to deepening the understanding of visual and optical performance of pseudophakic eye. A modest amount of positive ocular SA seemed to be a more preferable option for enhancing visual quality after aspheric ntraocular lense (IOL) implantation.