Residual Refractive Astigmatism Research Articles

Способ подбора данных кератометрии для расчета торичности ИОЛ

Purpose. To elaborate the customized principle of determining the actual zone of the corneal astigmatism based on keratotopographic data and compare the accuracy of calculating the toric IOL according to the actual zone and conventional keratometry. Material and methods. The study included 48 patients (48 eyes) who underwent toric IOL implantation. 3–6 months (5.1±0.6) after surgery, all patients were measured the residual refractive astigmatism. The toric IOL was retrospectively calculated according to the data of the actual keratotopographic zone determined by the proposed method (1st group) and according to conventional keratometry (2nd group). Vector and centroid analyses were used to estimate the error in calculating the IOL toricity. Results. The principles of determining the actual zone are based on the assumption that maximum visual acuity and visual quality can be achieved when the regularity of astigmatism in the central parts of the cornea corresponds to the regularity of toric IOL. The mean diameter of the selected actual zone was 2.93±0.61 (from 2.0 to 4.3 mm respectively). The average vector error of toricity calculation in 1st group was 0.30±0.31, in 2nd group – 0.42±0.30 (p=0.006). Centroid analysis showed similar values of centroid error in 1st group and 2nd group (0.09 and 0.08), while the dispersion was higher in 2nd group (0.42 and 0.51, respectively). Conclusion. The customized principle of selecting the actual zone according to topographic maps of the cornea showed a more accurate calculation of the IOL toricity compared with the use of conventional keratometry data. Key words: toric IOL, corneal astigmatism, IOL calculation accuracy, keratometry, keratotopography

Intraocular Lenses for Cataract Surgery

What Is the Issue?
 
 A cataract is an opacity of the lens and is the leading cause of reversible visual impairment worldwide. There are no medical treatments for cataracts but surgical procedures that replace the lens with a synthetic lens (called an intraocular lens [IOL]) have shown to be effective for restoring vision.
 Premium lenses, including lenses to correct astigmatism (called toric lenses), are available but may not be covered by public or private health plans.
 Given that there is an increased cost associated with toric lenses, there is a need to evaluate their effectiveness compared to other available corrective options, including glasses.
 
 What Did We Do?
 
 To inform decisions about the appropriate use of astigmatism-correcting IOLs, CADTH sought to identify and summarize literature that evaluates the clinical effectiveness of toric lenses against other corrective options.
 An information specialist conducted a search of peer-reviewed and grey literature sources. One reviewer screened citations, and selected and critically appraised the included studies.
 
 What Did We Find?
 
 One systematic review (SR), 3 randomized controlled trials (RCTs), 1 prospective nonrandomized study, and 6 retrospective nonrandomized studies were identified that evaluated the clinical effectiveness of toric versus nontoric IOLs implanted during cataract surgery, including 1 with a pediatric focus.
 Toric IOLs may be better than nontoric IOLs for postoperative astigmatism, but this may be dependent on the measurement of astigmatism evaluated (e.g., corneal astigmatism, residual refractive astigmatism, subjective refraction astigmatism, autorefraction astigmatism, spherical equivalent astigmatism, cylinder astigmatism, surgically induced astigmatism).
 Toric IOLs may be better than nontoric IOLs for postoperative uncorrected visual acuity (VA), but it is unclear if this results in a clinically meaningful difference to the patient. None of the studies reported on spectacle independence.
 Patient-centred outcomes were seldomly reported across the studies, and rarely used validated tools, making it difficult to conclude if there were patient-centred outcome differences between toric and nontoric IOLs.
 Harms were reported across the studies through intraoperative complications, postoperative complications, and adverse events. Postoperative complications were statistically higher in the toric group in the SR, but there were not statistically significant differences in harms reported in the primary studies.
 
 What Does it Mean?
 
 It is difficult to draw conclusions across the studies and outcomes due to the variation in how outcomes were reported or because few studies report on these outcomes.
 A proposed minimum set of core outcomes for cataract surgery was published in 2015. The studies included in this report did not align with this minimum set of outcomes. For example, as VA is not synonymous with improved visual functioning for patients, evaluating patient-reported visual functioning with a patient-reported outcome measure (PROM) tool is part of the minimum set of core outcomes. Future research should incorporate core outcomes, including PROMs.
 Although toric IOLs statistically improved uncorrected VA, when compared to nontoric lenses, statistical significance does not imply a difference that is clinically meaningful to a patient.

Accuracy of Astigmatism Calculation with the Barrett, Panacea, and enVista Toric Calculators.

To evaluate residual refractive astigmatism using the Panacea and enVista toric calculators, compared to the gold-standard Barrett toric calculator. A retrospective and comparative study was conducted in one center. We reviewed the medical records of all patients with a diagnosis of senile cataracts and regular corneal astigmatism, without previous corneal or intraocular surgery, who underwent phacoemulsification with implantation of a toric intraocular lens, who had pre- and postoperative corneal topography, biometry, and refraction measurements. The frequency of preoperative astigmatism according to the axis was 70 (84%) eyes showing with-the-rule (WTR) astigmatism, 9 (14%) eyes with against-the-rule (ATR) astigmatism, and 1 (2%) eye with oblique astigmatism. Regarding astigmatism prediction errors, there were statistically significant differences between the enVista and Panacea calculators (median of 0.39, 0.18, and 0.52 for Barrett, enVista, and Panacea, respectively). The residual astigmatism prediction error centroid was similar for the Barrett and enVista toric calculators, and both were lower compared to the Panacea calculator (x-component p < 0.001). The enVista toric calculator incorporating the Emmetropia Verifying Optical (EVO) toric calculator provides similar results to the gold-standard Barrett calculator.

Rotational stability of plate haptic toric intraocular lenses after combined 25-gauge vitrectomy and cataract surgery.

To evaluate the postoperative intraocular lens (IOL) rotational stability and residual refractive astigmatism following combined 25-gauge vitrectomy and cataract surgery with implantation of a plate haptic toric IOL. In this retrospective case series, 32 eyes of 32 patients underwent a combined 25-gauge vitrectomy and phacoemulsification for vitreoretinal diseases and cataract with regular corneal astigmatism of at least 1 diopter (D). A plate haptic toric IOL (AT Torbi 709M, Carl Zeiss Meditec AG) was implanted in all eyes. The outcome measures were rotational stability and refractive astigmatism up to 6mo postoperatively as well as the best corrected visual acuity (BCVA). Preoperative refractive astigmatism was 2.14±1.17 D, which was significantly reduced to 0.77±0.37 D six to eight weeks postoperatively and remained stable throughout the observation period (0.67±0.44 D at three months and 0.75±0.25 D at six months; for all groups: P<0.0001 compared to baseline). BCVA improved significantly from 0.36±0.33 logMAR preoperatively to 0.10±0.15 logMAR following surgery (P=0.02). Mean IOL axis deviation from the target axis was 3.4°±2.9° after six to eight weeks and significantly decreased over time (2.4°±2.6° six months after surgery; P=0.04). In one patient IOL, re-alignment was performed. Corneal astigmatism is significantly reduced following combined 25-gauge vitrectomy and cataract surgery. The plate haptic toric IOL position and axis remain stable during the observation period of six months.

Stereopsis after bilateral implantation of Toric intraocular lenses in high myopic cataract patients with astigmatism

PurposeTo evaluate near, intermediate, distance visual acuity and stereopsis after bilateral implantation of Toric intraocular lenses (IOLs) in high myopic patients with astigmatism. MethodsBilateral Toric or non-Toric IOL implantation (n ​= ​40 eyes each) was performed on high myopic cataract eyes with astigmatism. Best-corrected distance visual acuity (BCDVA), uncorrected intermediate visual acuity (UCIVA), uncorrected near visual acuity (UCNVA), residual refractive astigmatism (RRA), and near, intermediate, and distance stereoacuity were measured postoperatively at 7 days, 1 month, and 3 months. ResultsThe three-month postoperative BCDVA, UCIVA, and UCNVA of the Toric group were 0.08 ​± ​0.07, 0.30 ​± ​0.11, and 0.23 ​± ​0.14 LogMAR. All improved over the preoperative assessments (P ​< ​0.05). The RRA, UCIVA, and UCNVA were significantly better in the Toric group than the non-Toric group at all follow-up examinations (all P ​< ​0.05). At 3 months, the median near and intermediate stereoacuity of the Toric group were 100 (range 40 – 400) and 120 (range 50 – 400) arcsec, which were better than the non-Toric group (both P ​< ​0.05). Fine near stereopsis ≥100 arcsec was present in 65% of the Toric patients, and 50% had good intermediate stereopsis of ≥100 arcsec. However among non-Toric patients, only 15% and 5% achieved fine near and intermediate stereopsis. The postoperative BCDVA and best-corrected distance stereoacuity were similar in the two groups (P ​> ​0.05). ConclusionsIn bilateral high myopic cataract patients with astigmatism, Toric IOLs not only improved UCIVA, UCNVA, and RRA, but also enhanced near and intermediate stereopsis acuity.

Supplemental Toric Intraocular Lenses in the Ciliary Sulcus for Correction of Residual Refractive Astigmatism: A Review.

This study conducted a critical review of the peer-reviewed literature on the use of supplemental toric intraocular lenses (STIOL) in the ciliary sulcus to correct residual refractive astigmatism. This review used PubMed as a database from 1 January 2010 to 13 March 2023. According to the inclusion and exclusion criteria defined, 14 articles were selected for the current review. The data of 155 eyes were analyzed. Most of the studies reviewed had a short follow-up and poor or limited design, including case reports, case series, and retrospective cohorts. The follow-up period ranged from 43days to 4.5years. STIOL rotation was the most frequently described complication in the literature, with a mean rotation of 30.48 ± 19.90°. These patients required repositioning in 50 of 155 eyes (32.25%). Moreover, four eyes (2.58%) required scleral fixation sutures and two eyes (1.29%) iris fixation. Other complications were high intraocular pressure (3 eyes, 1.93%), transient corneal edema (2 eyes, 1.29%), corneal decompensation (2 eyes, 1.29%), and pigment dispersion (1 eye, 0.64%). From the total, 57.41% of eyes (89 eyes from 155) achieved within ± 0.50D of target refractive astigmatism. It is important to highlight that at least 52 eyes out of the 155 (33.54%) had an abnormal cornea with irregular astigmatism. STIOL seem to offer good visual and refractive outcomes. However, STIOL showed variable rotational stability, especially in some platforms. Further studies with a more robust design, methodology, and standardized analysis methods are needed to confirm these trends.

Outcomes of Single-Step Transepithelial Photorefractive Keratectomy Compared With Alcohol-Assisted Photorefractive Keratectomy Using Wave-Light EX500 Platform.

Purpose To compare the visual outcome of transepithelial photorefractive keratectomy (PRK) against alcohol-assisted PRK in treating low-to-moderate myopia with or without astigmatism. Setting Dhahran Eye Specialist Hospital, Dhahran, Saudi Arabia. Design This is a retrospective study. Methods Forty eyes of 22 patients with myopia from -0.75 to -6.00 diopters (D) with or without astigmatism from 0 to -3D were included in this study. Preoperative and postoperative data of 20 eyes from 11 patients who underwent transepithelial PRK were compared with 20 eyes from 11 patients who underwent alcohol-assisted PRK were collected and analyzed. The uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), manifest spherical equivalence (SE), manifest cylinder, vector analysis of astigmatism, and efficacy and safety indices were compared between the groups at a mean follow-up of one year postoperatively. Results Baseline characteristics were similar between groups, except the transepithelial PRK group had lower cylinder values than the alcohol-assisted PRK group by 0.69D. Regression analysis was used to control for the difference in the cylinder in all outcome parameters. Both groups had similar mean UDVA (p=0.73), CDVA (p=0.98), the proportion of eyes in either group achieved (20/20, 20/25, and 20/30) UDVA (p=0.72, 0.68 and 0.31 respectively) and percentage of eyes lost two lines of CDVA (p=1.0). There was no statistically significant difference between the two groups in regard to both efficacy and safety indices (p=0.55 and 0.67, respectively). Both groups had similar residual SE (p=0.72), the proportion of eyes within ±0.5D of SE (p=0.29), and residual refractive astigmatism (p=0.87). Both groups had similar difference vectors, surgically induced astigmatism, and correction index (p=0.82, 0.10, and 0.26, respectively). However, the transepithelial PRK group had lower target-induced astigmatism (TIA; p=0.01), higher magnitude of error (ME; p=0.05), and higher angle of error (AE; p=0.02) than the alcohol-assisted PRK group. Conclusion Transepithelial PRK had similar visual and refractive outcomes as alcohol-assisted PRK. This approach was considered as safe and effective as alcohol-assisted PRK in treating patients with low-to-moderate myopia with or without astigmatism.

Rotational stability and refractive outcomes of the DFT/DATx15 toric, extended depth of focus intraocular lens

PurposeTo quantitatively assess postoperative rotational stability and visual acuity with the DFT/DATx15 extended depth of focus (EDOF) toric intraocular lens (IOL).MethodsIn this prospective case series, thirty-five patients with a calculated IOL power between + 15.0 D and + 25.0 D, corneal astigmatism between 0.75 D and 2.25 D, and no significant ocular pathology underwent cataract surgery. Primary outcome was rotational stability of the IOL at 1 month post-operatively. Secondary outcomes included residual refractive astigmatism, absolute residual astigmatism prediction error, and monocular distance and intermediate visual acuities.ResultsMean absolute postoperative IOL rotation was 1.1 ± 0.2 degrees, with no rotation of more than 3 degrees at the final visit. Monocular mean best spectacle-corrected distance visual acuity (BSCDVA) improved from logMAR 0.27 ± 0.030 to 0.078 ± 0.017 (P < .001). Monocular uncorrected distance visual acuity (UCDVA) improved from 0.93 ± 0.096 to 0.18 ± 0.022 (P < .001). Best spectacle-corrected intermediate visual acuity (DSCIVA) was 0.17 ± 0.025, and uncorrected intermediate visual acuity (UCIVA) was 0.27 ± 0.040. Residual regular astigmatic refractive error was 0.21 ± 0.047 D.ConclusionsThe toric DFT/DATx15 EDOF lens showed excellent rotational stability and effective and predictable correction of astigmatism. Its refractive outcomes and safety profile were similar to those identified in prior studies of the non-toric DFT/DAT015 EDOF IOL. A small difference in monocular BSCDVA, of uncertain clinical significance, was found when comparing these outcomes with prior DFT/DAT015 data. The trial was retrospectively registered on November 5, 2021 (TRN ​​NCT05119127).

Does Adjunctive Under-flap CXL Reduce Regression for Hyperopic LASIK?

To investigate whether adding accelerated under-flap corneal cross-linking to hyperopic laser in situ keratomileusis (LASIK-ufCXL) affects postoperative stability and regression, visual and refractive outcomes, and subjective quality of vision. This prospective comparative contralateral eye study included 51 patients with hyperopia (102 eyes) who received LASIK-ufCXL in the eye with highest defocus equivalent (DEQ) or randomized when DEQ equal, with the contralateral control eye receiving LASIK alone. After excimer ablation, 0.25% riboflavin was instilled on the stromal bed for 3 minutes. The flap was repositioned, followed by a total irradiation dose of 3.24 J ultraviolet A (UV-A) light administered to the corneal surface, using 18 mW/cm2 UV-A for 3 minutes. Postoperative hyperopic regression (stability) was the primary outcome measure, defined by the difference in spherical equivalent (SEQ) at 1 week and 24 months postoperatively. Secondary measures reported uncorrected distance visual acuity, corrected distance visual acuity, cylinder vector analysis, subjective quality of vision, subjective night vision disturbances, and corneal haze. At 24 months, the SEQ stability (P = .4273) and the magnitude of hyperopic regression (P = .5613) did not significantly differ between groups, with a small trend showing hyper-opic regression of 0.50 diopters or greater being less frequent in LASIK-ufCXL eyes. There were no significant differences in accuracy, efficacy, and safety (P > .05), with a small trend of more residual refractive astigmatism in the LASIK-ufCXL group (P = .3216, Cohen's d: -0.29). Subjective quality of vision trended inferior in LASIK-ufCXL eyes (P = .2237, Cohen's d: -0.25), with a greater haze grading (P = .0466, Cohen's d: 0.41). Postoperative regression and stability were statistically equivalent between hyperopic LASIK vs LASIK-ufCXL, with identical safety. There were small clinical trends of lower efficacy, accuracy, and subjective quality of vision in LASIK-ufCXL eyes. [J Refract Surg. 2022;38(12):770-779.].

Refractive outcomes following bilateral implantation of a diffractive toric intraocular lens in a multisurgeon hospital setting

ObjectifÉvaluer l’astigmatisme réfractif résiduel postopératoire après l'implantation bilatérale de lentilles intraoculaires (LIO) trifocales toriques dans un contexte réel où évoluent plusieurs chirurgiens. NatureÉtude prospective regroupant plusieurs chirurgiens (6 chirurgiens dans 2 établissements). MéthodesOn a procédé à l'implantation bilatérale de LIO trifocales toriques (LIO AcrySof PanOptix; Alcon Vision LLC, Fort Worth, Texas, États-Unis) dans 140 yeux de 70 patients. Les patients ont été évalués au jour 1 et 3 mois après l'intervention. Le principal paramètre de mesure consistait en la présence d'astigmatisme résiduel. Au nombre des paramètres secondaires, mentionnons l'erreur de prédiction absolue, la rotation des LIO, l'acuité visuelle binoculaire non corrigée, l'acuité visuelle corrigée de près (40 cm), à distance intermédiaire (60 cm) et de loin (6 m) de même que l'indépendance aux lunettes évaluée par un questionnaire validé de satisfaction envers les LIO. RésultatsLe cylindre préopératoire moyen se chiffrait à 1,25 ± 0,72 D pour atteindre 0,39 ± 0,28 D 3 mois après l'intervention. Lors de l’évaluation à 3 mois, l'astigmatisme résiduel moyen était de 0,39 ± 0,28 D (fourchette : 0–1,25 D); l'astigmatisme postopératoire s’élevait à 0,5 D ou moins dans 118 yeux (84,3 %). Pour sa part, l'erreur de prédiction absolue moyenne était de 0,25 ± 0,21 D (fourchette : 0–1,13 D); l'erreur de prédiction absolue se chiffrait à 0,5 D ou moins dans 124 yeux (88,6 %). La rotation moyenne absolue était de 2,0 ± 2,7 degrés, comparativement aux valeurs de départ (fourchette : 0–15 degrés); 133 LIO (95,0 %) se situaient à ≤ 5 degrés de l'axe d'implantation. Enfin, 55 patients (79 %) ont signalé ne jamais porter de lunettes ou affirmé ne les porter que rarement pour la vision de près, au même titre que 66 patients (94 %) pour la vision à distance intermédiaire et que 67 patients (96 %) pour la vision de loin. ConclusionsSi l'on en croit les résultats de notre étude, l'implantation de LIO toriques PanOptix peut donner d'excellents résultats réfractifs et visuels qui s'accompagnent d'un astigmatisme résiduel peu marqué.

Toric intraocular lens implantation vs femtosecond laser-assisted arcuate keratotomy for correction of moderate astigmatism in cataract surgery.

To compare toric intraocular lens (TIOL) implantation and femtosecond laser-assisted arcuate keratotomy (FSAK) during phacoemulsification surgery in correction of moderate astigmatism. Clinical research study. Prospective randomized comparison study. Patients with age-related cataract and moderate preoperative corneal astigmatism of 1.25 to 3.0 diopters (D) were randomized into a TIOL implantation group and an FSAK group with symmetrical paired corneal arcuate keratotomies. The preoperative evaluation included corrected distance visual acuity (CDVA), corneal topography, autokeratometry, and ocular biometry. Postoperative examinations were performed at 1 month and 3 months and included CDVA and uncorrected distance visual acuity, manifest refraction, autokeratometry, and corneal topography. Vector analysis of astigmatic changes was performed using the Alpins vector method. This study comprised 75 eyes from 67 patients. The mean residual refractive astigmatism at 3 months was -0.63 ± 0.55 D in the TIOL group and -0.90 ± 0.53 D in the FSAK group ( P = .037) and was ≤1.00 D in 32 eyes (84%) and 25 eyes (64%), respectively. There were no statistically significant differences between the 2 groups in difference vector, angle of error, magnitude error, or correction index in the 3-month follow-up. The index of success was 0.32 ± 0.33 D in the TIOL group and 0.48 ± 0.29 D in the FSAK group ( P = .029). TIOL implantation showed better results in correcting moderate astigmatism. Despite this, FSAK is shown to be a safe technique for reducing astigmatism.

Type of residual astigmatism and uncorrected visual acuity in pseudophakic eyes

It is difficult to assess the pure impact of the type of residual astigmatism (with-the-rule; WTR, against-the-rule; ATR, and oblique astigmatism) on uncorrected distance visual acuity (UDVA) in pseudophakic eyes due to different age distribution of patients between those subgroups. We conducted the current study to investigate the association between astigmatism type and UDVA in eyes after cataract surgery with consideration for various confounding factors such as age. Data were retrospectively collected from 1535 pseudophakic eyes with corrected distance visual acuity (CDVA) of 20/20 or better, and spherical equivalent between − 0.125 D and 0.0 D. They were classified based on the pattern of residual refractive astigmatism into four groups; minimum astigmatism (< 0.5 D), WTR, ATR, and oblique astigmatism groups. The stepwise multivariate regression analysis showed that the magnitude of residual refractive astigmatism (standardized partial regression coefficient β = 0.559, p < 0.001), CDVA (β = 0.381, p < 0.001), minimum astigmatism group (β = − 0.188, p < 0.001), and WTR astigmatism group (β = − 0.058, p < 0.001) were significantly associated with UDVA (r2 = 0.795). Variables excluded from the multivariate regression model include age, preoperative corneal astigmatism, axial length, anterior chamber depth, intraocular lens power, and postoperative spherical equivalent. These results indicate that UDVA is significantly better in eyes with minimum and WTR astigmatism than in those with ATR and oblique astigmatism, after adjustment for confounding parameters. In pseudophakic eyes, oblique and ATR astigmatism exerts a greater impact on UDVA than WTR astigmatism does, even after controlling for age.

Comparing IOLM700 TK, Berdahl and Hardten astigmatism fix calculator and Barrett Rx formula in managing residual astigmatism due to toric intraocular lens misalignment.

Purpose:To compare the accuracy in astigmatism reduction by using IOLM 700 steep total keratometry (TK) axis, Berdahl and Hardten astigmatism fix, and Barrett Rx formula following misaligned toric intraocular lens (IOL).Methods:Ten patients with residual refractive astigmatism due to misalignment following toric IOL implantation were included in this retrospective study. They were analyzed at days 4, 7/8, and 10/11 following primary cataract surgery on the platform of Berdahl and Hardten astigmatism fix, Barrett Rx formula, and IOLM 700 to determine the optimum axis of repositioning, and underwent IOL realignment on the steep TK axis of IOLM 700 assisted by the Callisto eye. The final outcome parameters were subjective refraction and orientation of toric IOL assessed 22 ± 1 days following repositioning surgery. These parameters were fed in the Barrett Rx formula and its vector analysis graph was utilized to determine the predicted ideal axis with the least residual astigmatism and the estimated residual astigmatism if the toric IOL was realigned according to the axis suggested by Berdahl and Hardten astigmatism fix and Barrett Rx formula.Results:Realigning the toric IOL on IOLM 700 steep TK axis along with the Callisto eye reduces the residual refractive astigmatism significantly (P = 0.003) from 2.00 ± 0.78 D to 0.18 ± 0.12 D (90.5 ± 7.6%) in comparison to the estimated 0.57 ± 0.31 D (68.4 ± 21.9%) by Berdahl and Hardten astigmatism fix and 0.61 ± 0.33 D (66.4 ± 23.5%) by Barrett Rx formula.Conclusion:Realigning the misaligned toric IOL on the IOLM 700 steep TK axis gives a better reduction in the residual refractive astigmatism in comparison to Berdahl and Hardten astigmatism fix and Barrett Rx formula.

Comparative assessment of the accuracy of toric intraocular lens calculations

To compare the accuracy of toric intraocular lens (IOL) calculations on three modern toric calculators. 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. 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). Toric calculators ASSORT Toric IOL Calculator and the Kane formula showed higher accuracy of toric IOL calculation than EnVista Toric Calculator.

Clinical Outcomes of Monofocal Toric IOLs Using Digital Tracking and Intraoperative Aberrometry.

PurposeTo evaluate clinical outcomes of a toric IOL using digital tracking (DT) and intraoperative aberrometry (IA).MethodsThis was a retrospective, single surgeon study examining 151 eyes of 106 patients. Inclusion criteria were subjects who presented with visually significant cataracts (or as a candidate for clear lens extraction) and were implanted with a toric intraocular lens. Spherical equivalent prediction errors for IA and preoperative planning were calculated and compared. Preoperative and postoperative refractive data and monocular uncorrected distance visual acuity (UDVA) and corrected distance visual acuity (CDVA) were also collected at 3 months postoperatively.ResultsPostoperative actual residual refractive astigmatism with IA was 0.50 D or less in 140 eyes (92.8%) and was 0.50 D or less in 88 eyes (58.3%) with back-calculations based on preoperative planning. The absolute spherical equivalent prediction error was 0.50 D or less in 135 eyes (89.4%) for IA compared to 123 eyes (85.4%) for preoperative planning. Postoperative monocular UDVA was 0.10 logMAR or better in 124 eyes (82.1%) and 0.00 logMAR or better in 90 eyes (59.6%). Postoperative CDVA was 0.10 logMAR or better in 147 eyes (97.4%) and 134 eyes (88.7%) were 0.00 logMAR or better.ConclusionThe results demonstrate that toric implantation with DT and IA can provide excellent refractive and visual outcomes.

Clinical Outcomes After Femtosecond Laser-Assisted Arcuate Corneal Incisions versus Manual Incisions.

PurposeTo compare the relative effectiveness of Verion-LenSx guided femtosecond arcuate incisions and manual incisions in reducing postoperative refractive astigmatism.Patients and MethodsThis was a contralateral eye, prospective study that included subjects with 0.50 D to 1.75 D of corneal astigmatism who wanted less refractive astigmatism post cataract surgery. The surgeon used anterior keratometry and the Woodcock astigmatism nomogram for preoperative planning, while the LenSx femtosecond laser with the Verion Image Guided System was used to create all laser arcuate incisions. Manual incisions were planned using the Donnenfeld nomogram and made with a fixed-depth diamond knife. The primary outcome measure was the residual refractive astigmatism at 3 months postoperative. Secondary outcome measures included the manifest refraction, uncorrected distance visual acuity and the change in corneal astigmatism from 1 to 3 months postoperative.ResultsForty-one subjects were successfully enrolled in the study, with data from 38 subjects available at 3 months. There were no statistically significant differences in refractive astigmatism, corneal astigmatism, uncorrected distance visual acuity or manifest refraction between the Manual and Femto groups at either 1 month or 3 months. Significant changes in refractive and corneal astigmatism were noted between 1 months and 3 months. Ninety percent of eyes in both groups had ≤0.50 D of refractive astigmatism at 3 months. Two minor non-serious adverse events (full-thickness incisions of the cornea) occurred in two eyes of two different subjects in the Manual group; they were resolved without incident.ConclusionLaser arcuate incisions appear to be an effective means of reducing postoperative refractive astigmatism at the time of cataract surgery. No significant clinical differences were observed between incisions made manually and those made with an image-guided femto-second laser system. The lower number of minor adverse events experienced with the femtosecond laser system is an apparent advantage.

Clinical differences between toric intraocular lens (IOL) and monofocal intraocular lens (IOL) implantation when myopia is determined as target refraction

BackgroundThe aim of this study is to analyze and compare the clinical results of toric intraocular lens (IOL) and monofocal IOL implantation when the target refraction value is -3 diopter (D) in cataract patients with corneal astigmatism > 1.5 diopters (D).Methods We performed a retrospective chart review for patients with corneal astigmatism > 1.5D who underwent cataract surgery and their target refraction is -3D. 100 eyes (100 patients; monofocal IOL, 60; toric IOL, 40) were enrolled in the current study. Near and distant uncorrected visual acuity (UCVA), corrected VA, spherical equivalent and refractive, corneal astigmatism were evaluated before and after surgery.ResultsThe near UCVA of the toric IOL group (0.26 ± 0.33) after cataract surgery was significantly better than that of the monofocal IOL group (0.48 ± 0.32) (p = 0.030). The distant UCVA of the toric IOL group (0.38 ± 0.14) was also significantly better than that of the monofocal IOL group (0.55 ± 0.22) (p = 0.026). Best-corrected visual acuity (p = 0.710) and mean spherical equivalent (p = 0.465) did not show significant differences between the toric IOL group and the monofocal IOL group. In the toric IOL group, postoperative refractive astigmatism was − 0.80 ± 0.46D and postoperative corneal astigmatism was − 1.50 ± 0.62D, whereas the corresponding values in the monofocal IOL group were − 1.65 ± 0.77D and − 1.45 ± 0.64D; residual refractive astigmatism was significantly lower with toric IOL implantation compared with monofocal IOL implantation (p = 0.001). There were no postoperative complications.ConclusionsWhen myopic refraction such as -3D was determined as the target power in patients with corneal astigmatism, toric IOL implantation led to excellent improvement in both near and distant UCVA.

INFLUENCE OF THE SCLERAL LENS AND FLUID RESERVOIR THICKNESSES ON RESIDUAL ASTIGMATISM

PurposeThis study aims to determine if lens or tear fluid reservoir thicknesses (LT/FRT) may influence the presence of residual astigmatism and participant’s visual acuity.&#x0D; MethodsThe study was a randomized, non-dispensing, prospective study. Empirically and randomly chosen participants were fitted with 4 combinations (350 and 250 um LT fitted with 250 and 350 um FRT) of 16 mm diameter scleral lenses, designed using a corneo-scleral profiler software (sMap 3D, Visionary Optics, US). Lenses haptics were kept spherical for all lenses. They were evaluated under a slit lamp, anterior segement OCT (objective fluid reservoir and lens thicknesses), topography over lenses and aberrometry, after 30 minutes of lens wear. Spherico-cylindrical refraction and logMar acuity were also assessed.&#x0D; ResultsStudy population was composed of 24 participants aged 24.2 + 4.7 years old. Baseline refractive error was -2.3 + 1.6 D with -0.48 + 0.26 D of astigmatism. In vivo (OCT) lens A was 344.1 ± 15.4 um thick, fitted with a vault of 213.6 ± 42.4 um; Lens B was 346.2 ± 12.5/327.2 ± 44.8; Lens C was 260.3 ± 17.7/214.0 ± 40.6 um and Lens D was 262.2 ±13.2/330.8 ± 52.0 respectively. All lenses were found similarly decentered inferiorly by 0.10 to 0.15 um. BCVA was −0.32 + 0.08 (A), −0.21 + 0.10 (B), −0.28 + 0.08 (C), and −0.14 + 0.10 (D), compared to −0.25 + 0.08 (A), −0.11 + 0.10 (B), −0.23 + 0.06 (C), and −0.05 + 0.12 (D) when sphere only was compensated. Residual refractive astigmatism (RA = -0.50 to -0.75D) is found significantly higher based on the FRT (F=9.560; p=0.037) and not LT(F=0.429; p=0.522). There is no correlation be-tween RA and over-k readings (Lens A r=-0.078, p=0.773; Lens B r=−0.073, p=0.788; Lens C r=−0.345, p=0.171; Lend D r=0.019, p=0.944). Higher order aberrations, mostly vertical coma, were found clinically significant but not statistically different between lenses (A= 0.350 + 0.032; B=0.382 + 0.053, C=0.329 + 0.044 and D=0.385+ 0.062; p=0.776)&#x0D; ConclusionThis study proves that low level of RA may be found when scleral lenses are fitted on normal corneas. Its occurrence is related to the presence of high-order aberrations and less likely to lens flexure.

Rotation Characteristics of Three Toric Monofocal Intraocular Lenses.

PurposeTo evaluate the rotational stability of the three monofocal toric intraocular lenses (IOLs) via data from an online toric IOL back-calculator.MethodsA retrospective data review of an online toric IOL back-calculator, which allows users to input preoperative toric planning information, postoperative lens orientation, and subjective refraction. Inputted data were used to determine the optimal orientation of the toric IOL to minimize residual refractive astigmatism. Aggregate data from 3/11/2019 to 3/10/2020 were extracted and validated. Only data with ≥0.5D of residual refractive astigmatism were used in the study. Pre-operative intended IOL orientation and post-operative IOL orientation were used to calculate IOL rotation.ResultsAfter validation, 5397 entries were determined to represent patient eyes, of which 3238 represented the three monofocal IOLs evaluated. The rate of rotation for AcrySof, TECNIS, and enVista Toric IOLs was 72.7%, 83.4%, and 83.0%, respectively, and location only significantly impacted TECNIS IOLs. The magnitude of rotation for rotated IOLs was similar for all models and was significantly more for IOLs initially placed in the oblique axis. All IOL models tended to rotate in a counterclockwise direction (53.2%, 73.0%, 69.7%, respectively; p<0.05), and the tendency was greater for IOLs initially located horizontally.ConclusionThe AcrySof IQ Toric IOL was more rotationally stable than both the TECNIS and enVista Toric IOLs; there was no significant difference in rotational stability of the latter two.

&lt;p&gt;Primary Topography-Guided LASIK: A Comparative Study Comparing Treating the Manifest versus the Topographic Astigmatism&lt;/p&gt;

PurposeTo investigate if topography-guided laser in situ keratomileusis (LASIK) depending on the topographic astigmatism which is measured using the Topolyzer leads to a better refractive outcome when compared to treatment of the manifest refractive astigmatism in cases of myopic astigmatism.MethodsThis was a prospective non-masked, randomized study (block randomization) of postoperative vision and refraction of patients with myopic astigmatism that had LASIK using Contoura vision software. They were divided into three groups according to the treatment strategy, treating the manifest astigmatism in one group, the topographic astigmatism with compensation for the spherical power in the second group and treating the topographic astigmatism without changing the spherical power in the third group. It was conducted at Kasr Alainy Hospital and Dar Eloyon Hospital.ResultsThe postoperative uncorrected distant visual acuity (UDVA) in each group separately was better than the preoperative corrected distant visual acuity (CDVA) (58% (n=35) had UDVA better than 20/20 and gained 1 line or more); however, eyes treated with the topographic astigmatism without changing the spherical power showed the statistically best results (75% (n=15) had UDVA better than 20/20). The residual anterior corneal astigmatism was lower in this group (the mean 0.47 vs 0.95 and 0.59). No significant difference was noted in the residual refractive astigmatism, but it was also the least in that group.ConclusionTopography-guided LASIK is a safe and effective ablation profile for treatment of myopic astigmatism. Treating according to the topographic astigmatism shows the best outcome as regards the vision and residual astigmatism.