Assessment of Risk Factors Affecting Refractive Outcomes after Phacovitrectomy for Epiretinal Membrane.

PURPOSE: To investigate factors associated with refractive outcomes after phacovitrectomy for epiretinal membrane (ERM). METHODS: Retrospective review of patients undergoing phacovitrectomy for ERM was done. The main outcome measure was predictive refraction error (PE), defined as observed refraction error - target refraction error, calculated by the SRK/T, Haigis, and SRK II formulae. PE was measured at postoperative 1, 3, and 6 months. Simple and multiple linear regression analysis were used to evaluate factors associated with PE. RESULTS: A total of 53 eyes of 53 patients were included. The mean PEs at postoperative 1, 3, and 6 months were all negative, implying myopic shift in all patients regardless of the intraocular lens formula used. Haigis formula showed the least myopic shift among the three formulae (p = 0.001, Friedman test). There was no significant difference in PE depending on preoperative central macular thickness (CMT) in subgroup analysis. On stepwise multiple linear regression analysis, ERM etiology (ß = 0.759, p = 0.004, SRK/T formula; ß = 0.733, p = 0.008, Haigis formula; ß = 0.933, p < 0.001, SRK II formula), preoperative anterior chamber depth (ß = -0.662, p = 0.013, Haigis formula; ß = -0.747, p = 0.003, SRK II formula), and decrease of CMT (ß = -0.003, p = 0.025, SRK/T formula) were significantly associated with PE at postoperative 6 months. CONCLUSIONS: Myopic shift in PE was observed after combined phacovitrectomy for epiretinal membrane. ERM etiology, preoperative anterior chamber depth, and decrease of CMT were significantly associated with PE at postoperative 6 months. There was no difference in PE after surgery between the two groups defined by CMT (≥500 and <500 µm).

Cost-benefit analysis of a trifocal intraocular lens versus a monofocal intraocular lens from the patient's perspective in the United States.

PURPOSE: To conduct a cost-benefit analysis of AcrySof IQ PanOptix trifocal intraocular lens (TFNT00 IOL) versus AcrySof monofocal IOL (SN60AT) from the patient perspective in the United States (US). METHODS: A de novo Markov model was developed to estimate the mean total lifetime patient costs and vision-related quality of life (measured as quality adjusted life-years (QALYs)) with each intervention (TFNT00 and SN60AT) and the incremental differences between these two treatments. The resulting incremental quality of life gain was mapped to the US patient willingness to pay threshold of $50,000 per QALY gain to estimate the lifetime net monetary value, measured as the net monetary benefit of TFNT00 IOL. Model inputs (transition probabilities, costs, discount rate, utilities, and event rates) were derived from the FDA IDE study (NCT03280108), published literature, clinical experience, and other relevant sources. RESULTS: Bilateral cataract surgery with implantation of the advanced technology IOL (AT-IOL) TFNT00 provides improved vision-related quality of life (QALY gain of 0.67) at an incremental lifetime cost of $2,783 compared to monofocal IOL. This incremental QALY gain translated into a lifetime net monetary benefit of $30,941 at the patient willingness to pay threshold of $50,000/QALY gain. Results were most sensitive to disutility due to wearing glasses, patient out of pocket costs for bilateral AT-IOL procedure, and post-operative spectacle dependence rates. CONCLUSIONS: AcrySof IQ PanOptix IOL provides greater improvement in vision related quality of life compared to no presbyopia correction with a monofocal IOL. This study shows PanOptix is a cost-beneficial treatment strategy for patients willing to pay out of pocket for cataract surgery.

Health economics and manual small-incision cataract surgery: An illustrative mini review.

Cataract extraction is one of the most common surgical procedures performed worldwide. Manual small-incision cataract surgery (MSICS) is a popular technique of cataract extraction. Full economic evaluation of different techniques is of value to policy makers. This was a systematic review of published literature to present a brief overview of evidence available in respect of economic evaluation measures like cost effectiveness, cost utility, and cost parameters in cataract patients regarding MSICS. The data on these was sparse and heterogeneous. Direct costs of MSICS were lower than phacoemulsification (PE): $25.55 (PE) to $17.03 (MSICS) in India, $15 (MSICS) to $70 (PE) in Nepal, and $62.25 (MSICS) to $104.15 (PE) in Thailand. The cost utility analysis for MSICS demonstrated savings of $79.57 (INR6175) per gain in LogMAR BCVA, $8.91 (INR691) per QALY gained and $1.42 (INR110) per VF 14 score increment in India. Incremental cost-effectiveness ratio (ICER) $368.20 (13,215.50 Baht) for MSICS was better than $489.30 (17,561.70 Baht) for PE in Thailand. ICER for femto laser-assisted cataract surgery (FLACS) compared to was €10,703 in femtosecond laser-assisted versus phacoemulsification cataract surgery (FEMCAT) study. The corrected ICER for PE against MSICS is €146.50. The limited data available demonstrates that MSICS is the most cost-effective technique among FLACS, PE, and MSICS. MSICS scores over other existing alternatives of cataract extraction from cost-effectiveness and cost-minimization approaches. Further research is required in this area.

Assessment of the influence of keratometry on intraocular lens calculation formulas in long axial length eyes.

PURPOSE: Hyperopic surprises tend to occur in axial myopic eyes and other factors including corneal curvature have rarely been analyzed in cataract surgery, especially in eyes with long axial length (≥ 26.0 mm). Thus, the purpose of our study was to evaluate the influence of keratometry on four different formulas (SRK/T, Barrett Universal II, Haigis and Olsen) in intraocular lens (IOL) power calculation for long eyes. METHODS: Retrospective case series. A total of 180 eyes with axial length (AL) ≥ 26.0 mm were divided into 3 keratometry (K) groups: K ≤ 42.0 D (Flat), K ≥ 46.0 D (Steep), 42.0 < K < 46.0 D (Average), and all the eyes were underwent phacoemulsification cataract surgery with Rayner (Hove, UK) 920H IOL implantation. Prediction errors (PE) were compared between different formulas to assess the accuracy of different formulas. Multiple regression analysis was performed to investigate factors associated with the PE. RESULTS: The mean absolute error was higher for all evaluated formulas in Steep group (ranging from 0.66 D to 1.02 D) than the Flat (0.34 D to 0.67 D) and Average groups (0.40 D to 0.74D). The median absolute errors predicted by Olsen formula were significantly lower than that predicted by Haigis formula (0.42 D versus 0.85 D in Steep and 0.29 D versus 0.69 D in Average) in Steep and Average groups (P = 0.012, P < 0.001, respectively). And the Olsen formula demonstrated equal accuracy to the Barrett II formula in Flat and Average groups. The predictability of the SRK/T formula was affected by the AL and K, while the predictability of Olsen and Haigis formulas was affected by the AL only. CONCLUSIONS: Steep cornea has more influence on the accuracy of IOL power calculation than the other corneal shape in long eyes. Overall, both the Olsen and Barrett Universal II formulas are recommended in long eyes with unusual keratometry.

Assessment of biosafety and implantation feasibility of novel phakic refractive lens.

PURPOSE: We investigated the biosafety and implantation feasibility of a new phakic refractive lens (PRL) in rabbit eyes. METHODS: Short PRLs (S-PRLs), large PRLs (L-PRLs), and large-grooved PRLs (LG-PRLs), were prepared by molding medical-grade liquid silicon. The cytotoxicity and cellular adhesion of the PRLs was assessed in vitro. To assess implantation feasibility, the S-PRL, L-PRL, and LG-PRL were implanted in the posterior chamber of rabbit eyes and the relative position was assessed by optical coherence tomography. The intraocular pressures (IOP) were compared between the S-PRL, L-PRL, LG-PRL, and control groups to evaluate the PRL biosafety after implantation. RESULTS: The in vitro assays showed that cell viability and cellular adhesion in the S-PRL, L-PRL and LG-PRL groups was not significantly different to those in the control group throughout the study. After implantation into the posterior chamber of rabbit eyes, there were no obvious signs of inflammation or increases in IOP at each time point relative to the control group, demonstrating good biosafety of the PRL. The relative positions of the L-PRLs and LG-PRLs in the posterior chamber were appropriate and the retention frequencies were high. CONCLUSIONS: The newly developed LG-PRL showed good biosafety with negligible in vitro cytotoxicity, ocular inflammation, or fluctuations in IOP. The LG-PRL provided the best implantation feasibility. The grooves on the LG-PRL provided channels for aqueous humor circulation. The LG-PRL is a promising type of PRL with an appropriate size and surface structure for effective correction of refractive errors in rabbit eyes.

Assessment for Macular Thickness after Uncomplicated Phacoemulsification Using Optical Coherence Tomography.

PURPOSE: Macular edema including cystoid macular edema is one of the main causes of unfavorable visual outcomes after cataract surgery. The macular thickness and the occurrence of macular edema after uncomplicated cataract surgery was evaluated using optical coherence tomography (OCT) in this study. METHODS: Macular map images were taken by OCT before surgery and at 1 week, 1 month, and 2 months postsurgery. The subjects were classified into two groups (group 1, patients with no macular edema; group 2, patients with macular edema). Group 2 was defined as increase in central macular thickness (CMT) by 30% compared with that before surgery. The risk factors for macular edema were evaluated. Group 2 was divided into two subgroups: subclinical macular edema (group 2A) and cystoid macular edema (group 2B) and they were assessed in terms of the clinical course of best-corrected visual acuity and CMT. RESULTS: A total of 376 patients were enrolled in this study, of which 36 (9.57%, group 2) showed macular edema measured by OCT after the surgery. Univariate analysis for group 1 and 2 revealed that intracameral injection of epinephrine during phacoemulsification was associated with the development of macular edema. In group 2, five patients (1.33%) developed cystoid macular edema. Statistically significant differences in the clinical course of CMT were observed at 2 months (201.2 ± 23.1, 250.0 ± 29.8, and 371.0 ± 160.3 in group 1, group 2A, and group 2B, respectively; p < 0.001) and 1 month postoperatively (198.5 ± 23.6, 237.8 ± 40.9, and 314.0 ± 104.5 in group 1, group 2A, and group 2B, respectively; p < 0.001). Group 2B required additional treatment and eventually achieved best-corrected visual acuity of >0.2 with CMT in the normal range. CONCLUSIONS: The intracameral injection of epinephrine may cause macular edema after uncomplicated cataract surgery. Examination of CMT using OCT is recommended for the early detection of macular edema.

Immediate sequential bilateral surgery versus delayed sequential bilateral surgery for cataracts.

BACKGROUND: Age-related cataract affects both eyes in most cases. Most people undergo cataract surgery in both eyes on separate days, referred to as delayed sequential bilateral cataract surgery (DSBCS). An alternative procedure involves operating on both eyes on the same day, but as two separate procedures, known as immediate sequential bilateral cataract surgery (ISBCS). Potential advantages of ISBCS include fewer hospital visits for the patient, faster visual recovery, and lower healthcare costs. Nevertheless, concerns exist about possible bilateral, postoperative, sight-threatening adverse effects with ISBCS. Therefore, there is a clear need for evaluating evidence regarding the safety, effectiveness, and cost-effectiveness of ISBCS versus DSBCS. OBJECTIVES: To assess the safety of ISBCS compared to DSBCS in people with bilateral age-related cataracts and to summarise current evidence for the incremental resource use, utilities, costs, and cost-effectiveness associated with the use of ISBCS compared to DSBCS in people with bilateral age-related cataracts (primary objectives). The secondary objective was to assess visual and patient-reported outcomes of ISBCS compared to DSBCS in people with bilateral age-related cataracts. SEARCH METHODS: We searched CENTRAL (which contains the Cochrane Eyes and Vision Trials Register; 2021, Issue 5); Ovid MEDLINE; Ovid Embase; the ISRCTN registry; ClinicalTrials.gov; the WHO ICTRP; and DARE and NHS EED on the CRD Database on 11 May 2021. There were no language restrictions. We limited the searches to a date range of 2007 onwards. SELECTION CRITERIA: We included randomised controlled trials (RCTs) to assess complications, refractive outcomes, best-corrected distance visual acuity (BCDVA) and patient-reported outcome measures (PROMs) with ISBCS compared to DSBCS. We included non-randomised (NRSs), prospective, and retrospective cohort studies comparing ISBCS and DSBCS for safety assessment, because of the rare incidence of important adverse events. To assess cost-effectiveness of ISBCS compared to DSBCS, we included both full and partial economic evaluations, and both trial-based and model-based economic evaluations. DATA COLLECTION AND ANALYSIS: We used standard Cochrane methodological procedures and assessed risk of bias for NRSs using the ROBINS-I tool. For cost-evaluations, we used the CHEC-list, the CHEERS-checklist, and the NICE-checklist to investigate risk of bias. We assessed the certainty of evidence with the GRADE tool. We reported results for economic evaluations narratively. MAIN RESULTS: We included 14 studies in the review; two RCTs, seven NRSs, and six economic evaluations (one study was both an NRS and economic evaluation). The studies reported on 276,260 participants (7384 for ISBCS and 268,876 for DSBCS) and were conducted in Canada, the Czech Republic, Finland, Iran, (South) Korea, Spain (Canary Islands), Sweden, the UK, and the USA. Overall, we considered the included RCTs to be at 'high to some concerns' risk of bias for complications, 'some concerns' risk of bias for refractive outcomes and visual acuity, and 'high' risk of bias for PROMs. The overall risk of bias for NRSs was graded 'serious' regarding complications and 'serious to critical' regarding refractive outcomes.  With regard to endophthalmitis, we found that relative effects were estimated imprecisely and with low certainty, so that relative estimates were not reliable. Nonetheless, we found a very low risk of endophthalmitis in both ISBCS (1/14,076 participants) and DSBCS (55/556,246 participants) groups. Based on descriptive evidence and partially weak statistical evidence we found no evidence of an increased risk of endophthalmitis with ISBCS. Regarding refractive outcomes, we found moderate-certainty (RCTs) and low-certainty (NRSs) evidence there was no difference in the percentage of eyes that did not achieve refraction within 1.0 dioptre of target one to three months after surgery (RCTs: risk ratio (RR) 0.84, 95% confidence interval (CI) 0.57 to 1.26; NRSs: RR 1.02, 95% CI 0.60 to 1.75). Similarly, postoperative complications did not differ between groups (RCTs: RR 1.33, 95% CI 0.52 to 3.40; NRSs: 1.04, 95% CI 0.47 to 2.29), although the certainty of this evidence was very low for both RCTs and NRSs. Furthermore, we found low-certainty (RCTs) to very low-certainty (NRSs) evidence that total costs per participant were lower for ISBCS compared to DSBCS, although results of individual studies could not be pooled. Only one study reported on cost-effectiveness. This study found that ISBCS is cost-effective compared to DSBCS, but did not measure quality-adjusted life years using preferred methods and calculated costs erroneously. Finally, regarding secondary outcomes, we found limited evidence on BCDVA (data of two RCTs could not be pooled, although both studies individually found no difference between groups (very low-certainty evidence)). Regarding PROMs, we found moderate-certainty evidence (RCTs only) that there was no difference between groups one to three months after surgery (standardised mean difference -0.08, 95% CI -0.19 to 0.03). AUTHORS' CONCLUSIONS: Current evidence supports there are probably no clinically important differences in outcomes between ISBCS and DSBCS, but with lower costs for ISBCS. However, the amount of evidence is limited, and the certainty of the evidence was graded moderate to very low. In addition, there is a need for well-designed cost-effectiveness studies.

[Comparative assessment of the accuracy of toric intraocular lens calculations]. / Sravnitel'naya otsenka tochnosti rascheta toricheskikh intraokulyarnykh linz.

PURPOSE: To compare the accuracy of toric intraocular lens (IOL) calculations on three modern toric calculators. MATERIAL AND METHODS: The study comprised 35 eyes of 35 patients who underwent phacoemulsification with toric IOL implantation (EnVista Toric). Residual postoperative refractive astigmatism was calculated on three calculators: EnVista Toric Calculator, ASSORT Toric IOL Calculator and the Kane formula. Prediction error for each calculator was determined using vector analysis. RESULTS: The mean absolute deviation of predicted postoperative refractive astigmatism over actual astigmatism in diopters was distributed in the following way: 0.82±0.58, 0.70±0.67 and 0.72±0.76 using EnVista Toric Calculator, ASSORT Toric IOL Calculator and the Kane formula, respectively. Centroid prediction error was 0.08 (EnVista Toric Calculator), 0.06 (ASSORT) and 0.10 (Kane formula). There was a significantly smaller deviation using ASSORT and the Kane formula compared to the online calculator (p<0.05). CONCLUSIONS: Toric calculators ASSORT Toric IOL Calculator and the Kane formula showed higher accuracy of toric IOL calculation than EnVista Toric Calculator.

Immediate versus delayed sequential bilateral cataract surgery in children: a cost-effectiveness analysis.

BACKGROUND/AIMS: Children with bilateral cataracts may undergo immediate sequential bilateral cataract surgery (ISBCS), which involves surgery on both eyes during the same general anaesthesia, or delayed sequential bilateral cataract surgery (DSBCS), which involves operating on each eye on separate days and requires a second anaesthesia. ISBCS is viewed with caution because of the risk of bilateral endophthalmitis. Proponents of ISBCS emphasise that the incidence of serious complications is low and is outweighed by benefits such as avoidance of multiple anaesthesia, faster visual rehabilitation and potential for decreased costs. However, there is a paucity of literature regarding the cost-effectiveness of ISBCS in children. We conducted a cost-effectiveness analysis to determine whether ISBCS is more cost-effective than DSBCS from the societal and health system perspectives in Ontario, Canada, which has a universal, single-payer system. METHODS: A retrospective analysis of children who underwent ISBCS or DSBCS at a tertiary referral paediatric hospital was conducted. A decision tree was constructed using TreeAge Pro 2018 software. Clear visual axis was the measure of effectiveness. A time horizon of 8 weeks postoperatively was adopted. Both direct and indirect costs were included. RESULTS: Fifty-three children were included, 37 in the ISBCS group and 16 in the DSBCS group. ISBCS and DSBCS were equally effective. ISBCS resulted in cost-savings of $3,776 (95% CI:-$4,641 to $12,578) CAD, per patient, from the societal perspective and $2,200 (95% CI:-$5,615 to $10,373) CAD per patient from the health system perspective. CONCLUSION: ISBCS was less costly than DSBCS from both societal and health system perspectives while being equally effective.

Trends, Factors, and Outcomes Associated with Immediate Sequential Bilateral Cataract Surgery among Medicare Beneficiaries.

PURPOSE: To report the incidence of immediate sequential bilateral cataract surgery (ISBCS) and delayed sequential bilateral cataract surgery (DSBCS) and to identify factors associated with undergoing ISBCS. DESIGN: Retrospective cohort study. PARTICIPANTS: Medicare beneficiaries aged ≥ 65 who underwent ISBCS and DSBCS from 2011 through 2019. METHODS: Population-based analysis of the 100% Medicare fee-for-service carrier claims data. Logistic regression models were performed to evaluate factors associated with ISBCS. MAIN OUTCOME MEASURES: Incidence of ISBCS and DSBCS; demographic, ocular, and medical characteristics associated with receipt of ISBCS; and rates of endophthalmitis and cystoid macular edema (CME) after ISBCS or DSBCS. RESULTS: A total of 4014 (0.2%) ISBCS and 1 940 965 (99.8%) DSBCS patients were identified. Black (odds ratio [OR], 2.31; 95% confidence interval [CI], 2.06-2.59), Asian (OR, 1.82; 95% CI, 1.51-2.19), and Native American (OR, 2.42; 95% CI, 1.81-3.23) patients were more likely to receive ISBCS than White patients. Patients residing in rural areas showed a higher likelihood of ISBCS (OR, 1.26; 95% CI, 1.17-1.35) than patients in metropolitan areas. Patients undergoing surgery at a hospital, compared with an ambulatory setting (OR, 2.71; 95% CI, 2.53-2.89), were more likely to receive ISBCS. Patients with bilateral complex versus noncomplex cataract (OR, 3.23; 95% CI, 2.95-3.53) were more likely to receive ISBCS. Patients with a Charlson comorbidity index (CCI) of 1 to 2 (OR, 1.45; 95% CI, 1.29-1.62), 3 to 4 (OR, 1.70; 95% CI, 1.47-1.97), 5 to 6 (OR, 1.97; 95% CI, 1.62-2.39), and CCI ≥ 7 (OR, 1.97; 95% CI, 1.55-2.50) were more likely to receive ISBCS than those with a CCI of 0. In contrast, patients with glaucoma (OR, 0.82; 95% CI, 0.76-0.89), macular degeneration (OR, 0.75; 95% CI, 0.68-0.82), and macular hole or epiretinal membrane (OR, 0.55; 95% CI, 0.48-0.65) were less likely to undergo ISBCS than those without. Cumulatively, no significant difference was found in endophthalmitis rates within 42 days between ISBCS (1.74 per 1000 ISBCS procedures) and DSBCS (1.01 per 1000 DSBCS procedures; P = 0.15). Similarly, there was no significant cumulative difference between CME rates (P = 0.45) in ISBCS (1.79 per 100 ISBCS procedures) and DSBCS (1.96 per 100 DSBCS procedures). CONCLUSIONS: Overall use of ISBCS among Medicare beneficiaries remained low over the past decade, although rates of endophthalmitis and CME were comparable to DSBCS. Race, geography, and systemic and ocular comorbidities were associated with receiving ISBCS. ISBCS represents a potential opportunity to improve access to cataract surgery.

Intraoperative OCT for the assessment of posterior capsular integrity in pediatric cataract surgery.

PURPOSE: To study the morphology of the posterior lens cortex and posterior capsules (PCs) in pediatric patients with posterior lens opacities using intraoperative optical coherence tomography (iOCT). SETTING: Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China. DESIGN: Prospective observational study. METHODS: Pediatric patients with posterior lens opacities were imaged using iOCT during cataract surgery. The morphology of the posterior lens cortex and PC, along with the common patterns to indicate PC integrity, was assessed. Moreover, PC rent during surgery was observed. RESULTS: A total of 62 eyes from 53 patients were included. The mean age of patients was 3.8 years. 4 morphological variants of posterior lens opacity were observed: type I (34/62 [54.8%]) with an intact PC; type II (20/62 [32.3%]) with an intact PC, which protruded into the anterior vitreous; type III (3/62 [4.8%]) with a deficient PC and an inability to delineate the PC; and type IV (5/62 [8.1%]) with dense opacity and an inability to characterize the posterior cortex and PC. Phacoemulsification could be performed in types I and II. In types III and IV, manual nucleus removal was performed instead of phacoemulsification. 3 cases (100%) of type III PC dehiscence developed during surgery, whereas no cases developed PC dehiscence of other types. CONCLUSIONS: The morphology of the PC and posterior lens cortex in pediatric posterior lens opacities could be categorized, and PC integrity could be assessed using iOCT, which was useful to guide surgical strategies and increase safety in pre-existing PC dehiscence in pediatric cataract surgery.

Three-dimensional assessment of posterior capsule-intraocular lens interaction with and without primary posterior capsulorrhexis: an intraindividual randomized trial.

PURPOSE: To assess the morphologic and clinical features of posterior capsule-intraocular lens (IOL) interaction following cataract surgery with and without primary posterior continuous curvilinear capsulorrhexis (PPCCC) at a three-dimensional (3-D) level using Scheimpflug imaging. METHODS: This prospective intraindividual randomized comparative study comprised 56 patients (112 eyes) with age-related cataract who had bilateral cataract surgery and hydrophobic acrylic IOLs implantation. In randomized order, cataract surgery with PPCCC was performed in 1 eye (PPCCC group), and the posterior capsule was left intact in the fellow eye (NPCCC group). Scheimpflug imaging containing 25 images distributed in 360° was taken 1 day, 1 week, 1 month, and 3 months postoperatively. RESULTS: 46 patients completed 3 months follow-up. Posterior capsule-IOL interaction can be morphologically classified into two types including complete adhesion and floppy shape in PPCCC group, and six types including full area wave, full area flat, concentric ring wave, concentric ring flat, sector, and complete adhesion in NPCCC group. The adhesion index (AI), defined as the proportion of complete adhesion of posterior capsule-IOL in 25 cross-section tomograms, was 0.45 ± 0.45, 0.79 ± 0.37, 0.92 ± 0.26 and 1.00 ± 0.00 in PPCCC group, while 0.05 ± 0.18, 0.41 ± 0.47, 0.87 ± 0.34, and 0.96 ± 0.21 in NPCCC group at 1 day, 1 week, 1 month and 3 months postoperatively, respectively (p = 0.001, 0.001, 0.338 and 0.151). CONCLUSIONS: 3-D Scheimpflug imaging was favorable in observing of posterior capsule-IOL interaction. Faster posterior capsule adhesion to the IOL was found in PPCCC group than in NPCCC group.

Ratio of torus and equivalent power to refractive cylinder and spherical equivalent in phakic lenses - a Monte-Carlo simulation study.

BACKGROUND: Spherical and astigmatic powers for phakic intraocular lenses are frequently calculated using fixed ratios of phakic lens refractive power to refractive spherical equivalent, and of phakic lens astigmatism to refractive cylinder. In this study, a Monte-Carlo simulation based on biometric data was used to investigate how variations in biometrics affect these ratios, in order to improve the calculation of implantable lens parameters. METHODS: A data set of over sixteen thousand biometric measurements including axial length, phakic anterior chamber depth, and corneal equivalent and astigmatic power was used to construct a multidimensional probability density distribution. From this, we determined the axial position of the implanted lens and estimated the refractive spherical equivalent and refractive cylinder. A generic data model resampled the density distributions and interactions between variables, and the implantable lens power was determined using vergence propagation. RESULTS: 50 000 artificial data sets were used to calculate the phakic lens spherical equivalent and astigmatism required for emmetropization, and to determine the corresponding ratios for these two values. The spherical ratio ranged from 1.0640 to 1.3723 and the astigmatic ratio from 1.0501 to 1.4340. Both ratios are unaffected by the corneal spherical / astigmatic powers, or the refractive cylinder, but show strong correlation with the refractive spherical equivalent, mild correlation with the lens axial position, and moderate negative correlation with axial length. As a simplification, these ratios could be modelled using a bi-variable linear regression based on the first two of these factors. CONCLUSION: Fixed spherical and astigmatic ratios should not be used when selecting high refractive power phakic IOLs as their variation can result in refractive errors of up to ±0.3 D for a 8 D lens. Both ratios can be estimated with clinically acceptable precision using a linear regression based on the refractive spherical equivalent and the axial position.

Quantitative assessment of photic phenomena in the presbyopia-correcting intraocular lens.

This was a prospective study to evaluate the feasibility of the photic phenomena test (PPT) for quantifying glare, halo, and starburst. We compared two presbyopia-correcting intraocular lenses (IOLs), the Symfony IOL and the PanOptix IOL, as well as the monofocal Clareon IOL in 111 IOL-implanted eyes of 111 patients who underwent the PPT 1 month postoperatively. The reproducibility of photic phenomena with the PPT was assessed in 39 multifocal IOL-implanted eyes of 20 patients and among the examiners. Patients with ocular diseases, except for refractive errors, were excluded. The mean values of the groups were evaluated. Bland-Altman plots were used to analyze statistical data (Easy R version 1.37; R Foundation for Statistical Computing, Vienna, Austria). The PPT reproducibility assessment revealed no fixed bias or regressive significance. Reproducibility was confirmed. The glare size did not differ significantly between the Symfony, PanOptix, and Clareon groups. The halo size was significantly larger in the Symfony group (p < 0.01) than in the PanOptix group. The halo intensity was significantly brighter in the PanOptix group (p < 0.01) than in the Symfony group. In contrast, no halos were perceived in the Clareon group. The starburst size or intensity did not differ significantly between the Symfony, PanOptix, and Clareon groups. We identified the photic phenomenon related to various IOLs.

Should Artificial Tears Be Used During the Preoperative Assessment of Toric IOLs Before Age-Related Cataract Surgery? The TORIDE Study.

PURPOSE: To assess the impact of the use of artificial tears during the preoperative work-up performed before age-related cataract surgery, when a toric intraocular lens (IOL) was indicated. METHODS: This was a monocentric prospective study assessing 73 eyes of 51 patients, included consecutively after a preoperative work-up performed without artificial tears (no artificial tears group), when a toric IOL was indicated. Each included patient underwent a second series of examinations: biometry using the IOLMaster 700 (Carl Zeiss Meditec AG) and topography using the OPD-Scan II (Nidek), 1 minute after artificial tears instillation (artificial tears group; hyaluronate de sodium 0.15%, threalose 3% [Théalose; Théa]). Changes in anterior corneal astigmatism and subsequent changes in toric IOL calculation were analyzed. The error in predicted residual astigmatism was calculated. RESULTS: Anterior corneal astigmatism and total corneal astigmatism measured with the IOLMaster 700 were significantly modified when artificial tears were instilled before the examinations (1.51 ± 0.57 diopters [D], range: 0.75 to -3.55 vs 1.42 ± 0.63 D, range: 0.42 to 3.35 D; P = .043 and 1.59 ± 0.54 D, range: 0.87 to 3.48 vs 1.51 ± 0.59 D, range: 0.56 to 3.27 D, P = .038, respectively). This modification led to a change in IOL cylinder calculation in 43.8% of cases and to a change in implantation axis greater than 10° in 17.7% of cases. These changes were significantly greater in patients with a breakup time (BUT) less than 5 seconds (57.5% and 27.8%, with P = .009 and .029, respectively). In the subgroup of patients with a BUT of less than 5 seconds, the mean absolute error in predicted astigmatism was significantly lower after artificial tears instillation (0.48 ± 0.50 D, range: 0.00 to 2.79 vs 0.37 ± 0.25 D, range: 0.00 to 1.10 D, P = .048). CONCLUSIONS: Dry eye significantly impacted toric IOL calculations and should be taken into account during the preoperative assessments. Using artificial tears reduced the number of refractive errors. [J Refract Surg. 2021;37(11):759-766.].

Role of Scheimpflug imaging for assessment of posterior lens capsule in pediatric traumatic cataract.

PURPOSE: To find the accuracy of Scheimpflug imaging for the evaluation of posterior lens capsule and to assess the incidence of pre-existing posterior capsular tear (PCT) in pediatric traumatic cataracts. METHODS: It was a prospective, non-randomized, and interventional study. Scheimpflug imaging was done preoperatively to detect pre-existing PCT in pediatric traumatic cataracts after blunt trauma. All patients underwent cataract extraction with intraocular lens implantation. Intraoperatively, the posterior capsule status was noted and compared with the preoperative Scheimpflug images. RESULTS: Forty-seven eyes of 47 children having traumatic cataracts following closed-globe injury were included. There were 32 males and 15 females with a mean age of 10.91 ± 2.75 years. The mean duration of performing the Scheimpflug imaging from injury was 41.7 ± 7.78 days. Preoperative Scheimpflug imaging showed intact posterior lens capsule in 36 eyes and PCT in 11 eyes. Intraoperative, 37 eyes had an intact posterior lens capsule and 10 eyes had PCT. The Scheimpflug imaging did not detect the PCT in three eyes (false-negative), and in four eyes, PCT was detected falsely on Scheimpflug imaging (false-positive). The sensitivity and specificity of the Scheimpflug imaging were 70 and 89.18%, respectively. The accuracy of the technique was 85.11%. CONCLUSION: Scheimpflug imaging is a useful modality for the detection of PCT preoperatively in cases with doubtful posterior lens capsule integrity.

Time-efficiency assessment of guided toric intraocular lens cataract surgery: pilot study.

PURPOSE: To compare the time spent on toric intraocular lens (IOL) implantation during cataract surgery using a manual-marking vs a digital image-guided system (t Verion) for toric IOL alignment. SETTING: Instituto Oftalmológico Quirónsalud ophthalmology clinic, A Coruña, Spain. DESIGN: Experimental and longitudinal study. METHODS: A total of 98 eyes of 65 participants (68.2 ± 12.2 years) were divided into 2 groups: 49 eyes operated with toric IOL alignment using a manual-marking technique (manual group) and another 49 eyes operated using image-guided marking (Verion group). The primary variable for comparison between both groups was cataract surgery time. Other outcomes such as toric IOL misalignment, spherical equivalent, astigmatism, uncorrected distance visual acuity, and corrected distance visual acuity were also measured. RESULTS: The total cataract surgery time was 2:09 minutes shorter (P < .001) with the Verion system (12:12 ± 2:20 in 49 eyes operated) compared with the surgical procedure performed using manual marking (15:27 ± 3:04 in 49 eyes operated). One month after surgery, there were no statistical differences in terms of toric IOL misalignment between the Verion (3.38 ± 2.95 degrees) and the manual group (4.66 ± 3.95 degrees). No statistical differences were observed between groups for refractive and visual outcomes (P ≥ .05). CONCLUSIONS: The cataract surgery time was reduced when the procedure was assisted using the Verion system to align the IOL compared with manual marking, maintaining the same efficacy in terms of toric IOL misalignment, residual refraction, and visual acuity.

The Economic Impact of Presbyopia.

Presbyopia is the world's number one cause of vision loss with more than 1 billion individuals affected globally. The total global costs associated with correcting near vision impairment due to uncorrected presbyopia have been estimated at $30.8 billion for a comprehensive eye care model. Both cost to the patient and cost to society, which is greater in low-income countries relative to high-income areas, should be considered. Ultimately, surgical correction of the nonaccommodating dysfunctional natural lens may provide the "cure" for presbyopia. Presbyopia-correcting intraocular lenses (IOLs) may provide better visual acuity and fewer adverse effects. Patients are pursuing cataract surgery at a younger and younger age. Although this expands the viable pool for lens exchange, this younger group of patients has extreme demands and has a much more scrutinizing frame of reference for comparison (a milder cataract). Thus, they are at a much higher risk for dissatisfaction and have a much higher chance of noticing potential adverse effects from multifocal IOLs. Setting appropriate expectations and thoroughly educating patients preoperatively helps create a partnership with the patient and a strong foundation for a successful surgical outcome. A cure for presbyopia has always been considered the holy grail of ophthalmology. In 2021, ophthalmologists are moving closer to achieving this goal while also creating a safer, more productive, cost-effective solution to presbyopia on an individual and on a global level. [J Refract Surg. 2021;37(6 Suppl):S17-S19.].

Assessment of a software guided system to reduce pre-existing astigmatism in cataract surgery.

The aim of this pilot study was to assess the astigmatism after small incision cataract surgery by use of a novel software guided surgical technique. The software system guides the surgeon toward a hypothetical shape of the cornea. When this shape is achieved, the vertical meridian is relaxed and the incision does not produce any astigmatism. How that hypothetical shape is to be achieved by the surgeon is described. If preoperative astigmatism exists, the hypothetical shape calculated by the system takes that into account. This enables the surgeon to reduce preexisting astigmatism, without having to change the site or size of the standard 6 mm 12 o clock incision of SICS. Results: Results indicated that preoperative astigmatism reduced in 11 out of 14 cases at the end of 8 weeks, remained unchanged in one, and increased by less than 0.5D in two cases. This proves the hypothesis that the vertical corneal meridian is under higher tension and relaxing it by flattening the perpendicular meridian has a reducing effect on postoperative astigmatism.

Recurring themes during cataract assessment and surgery.

The aim of this review was to discuss frequently encountered themes such as cataract surgery in presence of age-related macular degeneration (AMD), dementia, Immediate Sequential Bilateral Cataract Surgery (ISBCS), discussing non-standard intraocular lens (IOL) options during consultation in the National Health Services (NHS) and the choice of the biometric formulae based on axial length. Individual groups of authors worked independently on each topic. We found that cataract surgery does improve visual acuity in AMD patients but the need for cataract surgery should be individualised. In patients with dementia, cataract surgery should be considered 'sooner rather than later' as progression may prevent individuals presenting for surgery. This should be planned after discussion of patients' best interests with any carers; multifocal IOLs are not proven to be the best option in these patients. ISBCS gives comparable outcomes to delayed sequential surgeries with a low risk of bilateral endophthalmitis and it can be cost-saving and efficient. Patients are entitled to know all suitable IOL options that can improve their quality of life. Deliberately withholding this information or pressuring patients to choose a non-standard IOL is inappropriate. However, one should be mindful of the not spending inappropriate amounts of time discussing these in the NHS setting which may affect care of other NHS patients. Evidence suggests Hoffer Q, Haigis, Hill-RBF and Kane formulae for shorter eyes; Barrett Universal II (BU II), Holladay II, Haigis and Kane formulae for longer eyes and BU II, Hill-RBF and Kane formulae for medium axial length eyes.