Toric Intraocular Lens Research Articles

Influence of Nd:YAG laser capsulotomy on toric intraocular lens rotation and change in cylinder power.

To investigate toric monofocal intraocular lens (TIOL) rotation and associated changes in cylinder power caused by Nd:YAG laser capsulotomy performed due to posterior capsule opacification (PCO). Ekol Eye Hospital, Izmir, Turkey. Prospective case series. 41 eyes of 20 women and 21 men were included in the study. Before and 1 month after Nd:YAG laser capsulotomy, TIOL tilt and decentration were determined with Scheimpflug camera, and TIOL axial rotation and the change in cylinder power induced by this rotation were measured by ray tracing aberrometry. The time interval between cataract surgery and Nd:YAG laser capsulotomy was noted. Rotational misalignment of the TIOL was measured as 4.65 ± 2.75 degrees (range 0 to 11 degrees) before vs 6.97 ± 2.92 degrees (range 0 to 13 degrees) after capsulotomy, and absolute rotation was 2.75 ± 1.94 degrees (range 0 to 7 degrees, P = .028). Before and after Nd:YAG laser capsulotomy, cylinder power was 0.24 ± 0.70 diopter (D) (range 0.00 to 0.63 D) vs 0.56 ± 0.77 D (range 0.02 to 0.91 D), respectively, with an absolute change in cylinder power of 0.34 ± 0.22 D (range 0.01 to 0.90 D, P = .001). After capsulotomy, there was a significant decrease in IOL tilt in the horizontal and vertical planes and an increase in decentration ( P < .05). Time interval (33.02 ± 12.9 months) and IOL horizontal decentration were independent factors affecting IOL rotation after capsulotomy ( P < .05). Nd:YAG laser capsulotomy may cause TIOL rotation as well as tilt and decentration, resulting in a change in the TIOL's corrective effect on corneal astigmatism. Although this change was clinically insignificant, it may be beneficial to consider that TIOL rotational misalignment may occur in patients undergoing early capsulotomy.

Visual Function After Implantation of Trifocal and Trifocal Toric Intraocular Lenses Using Intraoperative Aberrometry.

To evaluate patient outcomes and visual function following trifocal and trifocal toric intraocular lens (IOL) implantation using intraoperative aberrometry at a single site in the US. This prospective, single arm study included 21 subjects that completed 3 month follow-up. Inclusion criteria were visually significant cataract and potential post-operative visual acuity of 20/25 or better. Endpoints included postoperative prediction error, refractive outcomes, uncorrected visual acuities at distance (UDVA), intermediate (UIVA), and near (UNVA), contrast sensitivity, and subject responses on the modified Visual Function Quality of Life Questionnaire (VF-14 QOL). Binocular UDVA, UIVA, and UNVA were 20/25 or better in 100% (21/21), 100% (21/21), 90% (19/21) of subjects. The absolute prediction error was 0.50 D or less in 79% (33/42) of eyes, and 81% (34/42) and 86% (36/42) of eyes achieved ≤0.5 D of residual astigmatism and manifest refraction spherical equivalent, respectively. On the modified VF-14 QOL, driving at night, reading small print, and reading a newspaper or book were the tasks that had the lowest percentages of subjects reporting no difficulty or a little difficulty. Implantation with trifocal and trifocal toric IOLs using intraoperative aberrometry can provide high refractive precision, leading to excellent visual performance and low visual task difficulty at all ranges (distance, intermediate, and near).

Outcomes After Implantation of a Trifocal Toric Intraocular Lens Using Intraoperative Aberrometry, Digital Image Tracking, and Femtosecond Laser.

To evaluate the refractive and visual acuity outcomes when using trifocal toric intraocular lenses (IOLs), femtosecond laser assisted cataract surgery (FLACS), swept-source optical coherence tomography (SS-OCT) biometry, digital image tracking (DT) and intraoperative aberrometry (IA). This prospective, single-arm, observational study of refractive and visual outcomes included 40 eyes of 34 subjects. Preoperative biometry was performed with the Argos, FLACS and digital marking with LenSx, and IA and DT with ORA. Eyes were implanted with the Clareon PanOptix toric IOL. Study outcome measures included absolute prediction error, residual refractive astigmatism, and monocular uncorrected and distance corrected visual acuity at distance (UDVA, CDVA), intermediate (UIVA, DCIVA; 60cm), and near (UNVA, DCNVA; 40cm). Mean absolute prediction error (spherical equivalent) was 0.43 ± 0.36 D, and the percentage of eyes with absolute prediction error ≤ 0.5 D was 72.5% (29/40 eyes). Mean residual astigmatism was 0.36 ± 0.65 D, and the percentage of eyes with residual astigmatism ≤ 0.5 D was 80% (32/40 eyes). Monocular UDVA, UIVA, and UNVA was 20/25 or better in 75%, 64%, and 87% of eyes respectively. Monocular CDVA, DCIVA, and DCNVA was 20/25 or better in 95%, 64%, and 87% of eyes respectively. The results of this study suggest that trifocal toric implantation with SS-OCT, FLACS, DT, and IA can provide excellent refractive and visual outcomes.

Clinical Performance of an Omnidirectional Aberration-Free Trifocal Toric Intraocular Lens.

To assess the refractive and visual outcomes at different distances following cataract surgery with implantation of an omnidirectional aberration-free diffractive trifocal toric intraocular lens (IOL). A total of 24 patients who underwent bilateral implantation with the TrivaT-aAY IOL were analyzed at 3-4 months post-surgery. Refractive error, monocular and binocular uncorrected and corrected-distance visual acuity (UDVA, CDVA), uncorrected and corrected-distance intermediate visual acuity (UIVA, CDIVA) at 60 cm, uncorrected and corrected-distance near visual acuity (UNVA, CDNVA) at 40 cm, monocular and binocular defocus curve and rotational stability were measured. Patients also completed the Catquest-9SF questionnaire at the last postoperative visit. The postoperative mean values of binocular logMAR CDVA, CDIVA and CDNVA were -0.06±0.06, 0.05±0.07 and 0.07±0.08, respectively. One hundred percent of patients showed a cumulative binocular CDVA ≥20/25, and 95.83% of patients showed a cumulative binocular CDIVA and CDNVA ≥20/32. The mean postoperative spherical equivalent was 0.07±0.26D and 100% and 97.92% eyes were within ±1.00D and ±0.50D, respectively. The mean postoperative refractive cylinder was -0.22±0.29D and 100% and 89.58% eyes showed a value ≤1.00D and ≤0.50D, respectively. The defocus curves showed a wide range of useful vision, with visual acuity values >0.2 logMAR. Mean absolute IOL rotation was 2.19±2.17 degrees and all eyes had a rotation <10 degrees. For the questionnaire, 95.83% of patients reported being quite satisfied to very satisfied with their vision and about 79.17% did not report any difficulty with their vision in their everyday life. Between 83.33% and 95.83% of patients reported no difficulty performing different tasks. No intra- and postoperative complications were reported during the follow-up. Our study shows that the TrivaT-aAY IOL provides good visual acuities at all distances and refractive outcomes with excellent rotational stability and with high satisfaction among our patients after its implantation.

Astygmatyzm w kontekście operacji usunięcia zaćmy z wykorzystaniem torycznych soczewek wewnątrzgałkowych – aktualny przegląd piśmiennictwa

Assessment and management of astigmatism is often difficult, and one of the specific situations in which this problem must be faced is when a patient with astigmatism is qualified for cataract surgery. A relatively predictable method of astigmatism correction during a single procedure and also the method of choice in the treatment of cataracts accompanied by corneal astigmatism is cataract phacoemulsification with implantation of toric intraocular lenses. The aim of the study is to review the current literature on this topic. The prevalence of corneal astigmatism ≥1.0 D in patients with cataract varies in various studies from 34.8 to 66.9%, which illustrates the scale of demand for this procedure. The paper discusses the key aspects of pre-operative assessment of astigmatism, including the changes that occur with the aging process. The importance of measuring the posterior corneal astigmatism and the consequences of its neglect in the form of deviations in the assessment of total corneal astigmatism and postoperative residual refractive errors were emphasized. Attention was paid to available updates of toric calculators and innovations in cases of irregular astigmatism.

Wybrane zagadnienia dotyczące implantów torycznych wszczepianych podczas operacji usunięcia zaćmy i operacji refrakcyjnej wymiany soczewki

Toric intraocular lens implantation is currently a preferred method of astigmatism correction in patients with cataract and during refractive lens exchange. Astigmatism-correcting lenses enable significant visual acuity improvement and increase patient satisfaction after the surgery. In order to achieve optimal postoperative results, it is required to conduct proper qualification, thorough and reliable keratometry measurements before surgery as well as consider potential contraindications to toric intraocular lens implantation. The aim of this review is to outline current indications and contraindications for toric lens implantation and to introduce toric lens power calculation methods

Toric Monofocal Intraocular Lenses for the Correction of Astigmatism during Cataract Surgery: A Report by the American Academy of Ophthalmology

To review the published literature evaluating the visual and refractive outcomes and rotational stability of eyes implanted with toric monofocal intraocular lenses (IOLs) for the correction of keratometric astigmatism during cataract surgery and to compare those outcomes with outcomes of eyes implanted with nontoric monofocal IOLs and other astigmatism management methods performed during cataract surgery. This assessment was restricted to the toric IOLs available in the United States. A literature search of English-language publications in the PubMed database was last conducted in July 2022. The search identified 906 potentially relevant citations, and after review of the abstracts, 63 were selected for full-text review. Twenty-one studies ultimately were determined to be relevant to the assessment criteria and were selected for inclusion. The panel methodologist assigned each a level of evidence rating; 12 studies were rated level I and 9 studies were rated level II. Eyes implanted with toric IOLs showed excellent postoperative uncorrected distance visual acuity (UCDVA), reduction of postoperative refractive astigmatism, and good rotational stability. Uncorrected distance visual acuity was better and postoperative cylinder was lower with toric IOLs, regardless of manufacturer, when compared with nontoric monofocal IOLs. Correcting pre-existing astigmatism with toric IOLs was more effective and predictable than using corneal relaxing incisions (CRIs), especially in the presence of higher magnitudes of astigmatism. Toric monofocal IOLs are effective in neutralizing pre-existing corneal astigmatism at the time of cataract surgery and result in better UCDVA and significant reductions in postoperative refractive astigmatism compared with nontoric monofocal IOLs. Toric IOLs result in better astigmatic correction than CRIs, particularly at high magnitudes of astigmatism. Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Scleral Fixation of a Single-Piece AcrySof Toric Intraocular Lens: A Case Report

Purpose: To describe a simple and least invasive surgical method of transscleral fixation of a dislocated single-piece AcrySof® toric intraocular lens (IOL).Case summary: A 62-year-old male was referred with dislocated toric IOL (SN6AT4, AcrySof® IQ Toric; Alcon Laboratories, Fort Worth, TX, USA) in his right eye after an uneventful cataract surgery. Scleral fixation using the toric IOL was performed by placing the suture knot at the optic-haptic junction right beside the toric axis markings which easily achieved the desired positioning of the axis. The preoperative uncorrected distance visual acuity was 20/400 and it improved to 20/60 at 1 week after repositioning of the IOL and the IOL was well-centered with its toric alignment within 5 degrees of the intended axis.Conclusions: Transscleral fixation of single-piece AcrySof toric IOLs is easy to learn technique, which reduces surgical time with minimal manipulation and enables IOL stability with good postoperative toric axis alignment.

Comments on comparison of clinical outcomes of Eyecryl Toric and Alcon Toric intraocular lenses: A real-world study.

Comments on comparison of clinical outcomes of Eyecryl Toric and Alcon Toric intraocular lenses: A real-world study.

Comparison of dynamic visual acuity after implantation of toric bifocal or trifocal intraocular lens in age-related cataract patients: a randomized controlled trial.

To investigate the dynamic visual acuity (DVA) after implantation of toric bifocal or trifocal intraocular lens in age-related cataract patients. This was a prospective randomized controlled trial. Of one hundred and twenty-four patients enrolled and randomized to receive unilateral phacoemulsification and toric trifocal (939 M/MP, Carl Zeiss Meditec AG, Jena, Germany) or toric bifocal (909 M, Carl Zeiss Meditec AG, Jena, Germany) intraocular lenses (IOL) implantation, ninety-nine patients completed the follow-up and were included in final analysis. Postoperatively, uncorrected and corrected distance (UDVA and CDVA), intermediate (UIVA and DCIVA) and near (UNVA and DCNVA) static visual acuity, manifest refraction and uncorrected and corrected distance DVA (UDDVA and CDDVA) at 20, 40 and 80 degrees per second (dps) were evaluated at one week, one month and three months. Three months postoperatively, the UDVA were 0.13 ± 0.11 and 0.14 ± 0.13 in the toric trifocal and bifocal IOL group, respectively. Significant better UIVA (trifocal, 0.17 ± 0.13 vs. bifocal, 0.23 ± 0.13, p = 0.037) and DCIVA (trifocal, 0.16 ± 0.11 vs. bifocal, 0.20 ± 0.12, p = 0.048) were observed in patients implanting toric trifocal than bifocal IOL at three months postoperatively. Patients implanted with toric bifocal IOL obtained better CDDVA at 80 dps (0.5607 ± 0.2032) than the trifocal group (0.6573 ± 0.2450, p = 0.039) at three months. Postoperative UDDVA and CDDVA at 20, 40 and 80 dps were significantly associated with age (p < 0.05, respectively) and postoperative static visual acuity (p < 0.05, respectively). Toric trifocal IOL provides better static intermediate visual acuity, and toric bifocal IOL implantation provides better distance dynamic visual acuity at high speed.

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

Repositioning Rates of Toric IOLs Implanted in Cataract Surgery Patients: A Retrospective Chart Review.

To determine the incidence of postoperative repositioning of toric intraocular lenses (IOLs) due to clinically significant rotation. This study included consecutive cataract patients with pre-existing astigmatism who had undergone cataract surgery with toric IOL implantation by a single experienced surgeon. Case records of patients who were recommended to undergo toric IOL repositioning surgery due to clinically significant postoperative IOL rotation from the implanted axis were identified. The need for a secondary intervention to manage residual astigmatism was based upon postoperative residual astigmatic error ≥0.75 D, the patient's qualitative dissatisfaction with the level of postoperative distance vision, dilated post-op examination, and confirmation of the significant potential for astigmatism reduction. Case records of 993 eyes implanted with AcrySof toric (N = 362), Tecnis Toric I (N = 53), Tecnis Toric II (N = 308), or enVista Toric IOLs (N = 270) were included. Postoperative toric IOL repositioning was recommended in 16 eyes (1.6%). The repositioning rate was highest in the eyes implanted with Tecnis Toric I (5.7%), followed by AcrySof Toric (2.2%), enVista Toric IOLs (1.1%), and Tecnis Toric II (0.6%). This real-world analysis of eyes implanted with toric IOLs revealed that the rate of surgical IOL repositioning due to clinically significant IOL rotation was lower than 2% for enVista and Tecnis Toric II IOLs. When needed and with appropriate planning, toric IOL repositioning can be very successful.

Comparison of two objective methods for measuring postoperative toric intraocular lens orientation under the natural pupil.

To evaluate and compare the accuracy of iTrace and CASIA2 in measuring the postoperative orientation of toric intraocular lens (IOL) without mydriasis. Tianjin Medical University Eye Hospital, Tianjin, China. Prospective cohort study. Patients with SN6AT toric IOLs implanted after cataract surgery were enrolled. 1 month after surgery, the toric IOL orientation were measured by iTrace and CASIA2 in non-mydriatic, semi-dark conditions. Then, the toric axis was directly reviewed using the slit-lamp under full mydriasis. Axis measurement differences between each of the 2 devices and the slit-lamp, described as their relative differences (RDs), were calculated and compared. The percentage of RDs within 5 degrees, within 10 degrees and greater than 30 degrees were analyzed. 77 eyes of 70 patients were included. Generally, the mean toric axis measurement RDs of CASIA2 and iTrace were 9.24 ± 10.53 degrees and 13.89 ± 15.47 degrees respectively ( P = .04). For CASIA2 (72 eyes), 54.17% (39), 72.22% (52), and 4.17% (3) of eyes had RDs within 5 degrees, within 10 degrees and greater than 30 degrees, compared with 40.00% (28), 61.43% (43) and 12.86% (9) for iTrace (70 eyes). The 95% limits of agreements of CASIA2 with slit-lamp was narrower than that of iTrace with slit-lamp. The median RD of CASIA2 was significantly smaller in eyes with pupil ≥4 mm under dark condition compared with eyes with pupil <4 mm ( P = .03). CASIA2 demonstrates greater precision in measuring toric IOL orientation under non-mydriatic conditions compared with iTrace. Moreover, the accuracy of CASIA2 is enhanced in cases of pupil >4 mm.

Head-to-Head Comparison of Intermediate Vision of Two Monofocal Intraocular Lenses.

To compare intermediate visual outcomes in patients previously implanted with bilateral Clareon monofocal IOLs versus bilateral Eyhance IOLs. This was a non-interventional, single-center, examiner-masked, comparative study. Participants were cataract patients presenting at least 3 months after uncomplicated, bilateral implantation of either Clareon or Eyhance non-toric and toric IOLs. Outcomes measures included binocular distance-corrected intermediate visual acuity (DCIVA), binocular corrected distance visual acuity (CDVA), binocular best-corrected defocus curve, postoperative mean residual spherical equivalent (MRSE), and residual astigmatism. A total of 620 eyes of 310 subjects (155 subjects per group) were evaluated. The mean difference in DCIVA was 0.05 logMAR between the Eyhance and Clareon IOLs which was significant (p < 0.01), but within the 0.1 logMAR non-inferiority margin. Mean CDVA of the Clareon group was 0.01 ± 0.03 logMAR compared to 0.02 ± 0.03 logMAR of the Eyhance Group (p > 0.05). Defocus curves from +1.0 D to -3.0 D were not clinically nor statistically different between the Clareon and Eyhance groups (p > 0.05). The results of this study show that bilateral implantation of Clareon monofocal IOLs and Eyhance monofocal IOLs lead to similar distance and intermediate visual outcomes.

Comparison of toric intraocular lens calculation with the integrated K method and three single biometric devices.

To compare astigmatic outcomes using the Integrated K method and anterior surface keratometry from 3 different biometric devices. Lions Eye Institute, Perth, Australia. Retrospective case series. Eyes of patients who underwent uneventful cataract surgery were analyzed. Predicted postoperative astigmatism was calculated for Integrated K method, IOLMaster 700, Lenstar and Pentacam. The mean centroid error in predicted postoperative refractive astigmatism (PE), mean absolute PE and percentage of eyes within 0.5 diopter (D), 0.75 D and 1 D of absolute magnitude of PE were compared. A subset analysis was done where the difference in cylinder magnitude between the 2 methods was more than 0.25 D. Spherical prediction outcomes were also analyzed. 241 eyes of 139 patients were included in the study. The mean centroid PE of Integrated K method (-0.07 @ 69) was significantly different from IOLMaster and Pentacam. The mean absolute PE with Integrated K method (0.33 ± 0.17) was significantly lower than all 3 devices. The percentage of eyes within 0.5 D and 0.75 D of absolute magnitude of PE was 82% and 99% for Integrated K method, 76% and 95% for IOLMaster and Lenstar, and 60% and 86% for Pentacam. In the subset analysis, the improvement in accuracy of the Integrated K method compared with a single device was greater in terms of the percentage of eyes predicted within 0.5 D. The Integrated K method did not impact the spherical prediction outcomes. The integrated K method is more accurate and precise than anterior surface keratometry from a single biometric device.

Accuracy of Toric Intraocular Lens Calculations Using Estimated Versus Measured Posterior Corneal Astigmatism

To compare the prediction accuracy of toric intraocular lens calculations using estimated vs measured posterior corneal astigmatism (PCA). Retrospective case series. A total of 110 eyes of 110 patients with uncomplicated toric intraocular lens implantation were included in this study. Predicted postoperative refractive astigmatism was calculated with the Barrett Toric Calculator using the estimated PCA (E-PCA), the measured IOLMaster 700 PCA (I-PCA), and the measured Pentacam PCA (P-PCA). Refractive astigmatism prediction errors (RA-PEs), including their trimmed (tr-) centroid (mean vector), spread (precision), tr-mean absolute RA-PE (accuracy), and percentage within a certain threshold, were determined using vector analysis and compared between groups. University Eye Clinic, Maastricht University Medical Center+, the Netherlands. The tr-centroid RA-PEs of the E-PCA (0.02 diopter [D] at 82.2°), the I-PCA (0.08 D at 35.5°), and the P-PCA (0.09 D at 69.1°) were significantly different from each other (P < .01), but not significantly different from zero (P = .75, P = .05, and P = .05, respectively). The E-PCA had the best precision (tr-mean 0.40 D), which was not significantly lower than the I-PCA (0.42 D, P = .53) and P-PCA (0.43 D, P = .06). The E-PCA also had the best accuracy (0.40 D), which was not significantly different from the I-PCA (0.42 D, P = .26) and significantly better than the P-PCA (0.44 D, P < .01). The precision and accuracy of the I-PCA did not significantly differ from those of the P-PCA. There were no statistically significant differences in the percentage of eyes within a certain absolute RA-PE threshold. The Barrett Toric Calculator using the E-PCA, I-PCA, or P-PCA showed a comparable prediction of postoperative refractive astigmatism in standard clinical practice.

Refractive errors occurring with tilt of intraocular lenses.

A thin lens technique was developed to determine how the effective powers of toric monofocal intraocular lenses (IOLs) are influenced by tilt and the refractive errors associated with the tilt. A series of steps determined the effective power of the cornea at the IOL, the IOL power, the effective power of the tilted IOL, the correction required at the front of the eye and the power of an IOL that would compensate for the tilt. The correction was determined by starting at the ideal reduced image vergence at the IOL, backwards raytracing to obtain a reduced image vergence at the cornea, and subtracting the cornea power from this reduced image vergence. Examples are presented for different situations where the IOL is either tilted about the vertical or an oblique axis. Raytracing with a thick lens verified the accuracy of the technique.

Online intraocular lens calculation.

To showcase the majority of online intraocular lens (IOL) calculation tools and highlight some of their characteristics. Online tools are available for preoperative and postoperative IOL-related calculations, including IOL power and toricity selection for standard patients, patients who underwent prior refractive surgery, keratoconus, limbal relaxing incisions for astigmatism management, realignment of a misplaced or rotated toric IOL, surgical induced astigmatism (SIA), formulae comparison, and other tools. As there are new online developments and technology is advancing rapidly, we hope that this review will assist ophthalmologists in becoming acquainted with a large variety of online tools.

Contribution of Posterior Corneal Astigmatism to Total Corneal Astigmatism among Saudi Population

Background: Astigmatism is an error of refraction in which incident parallel rays cannot be focused on a single point. It could be corneal astigmatism (CA), lenticular astigmatism (LA), or both. Regarding CA, it is due to the difference in the corneal curvature in the different meridians of both the anterior and posterior surfaces. The anterior and posterior corneal surfaces contribute to total corneal astigmatism (TCA). Newer technologies, such as slit-scanning technology, Scheimpflug devices, and optical coherence tomography, are now used in the clinical setting for measuring the posterior corneal surface. However, it has been shown that relying only on the anterior corneal surface measurement and neglecting the relationship between the anterior and posterior corneal surfaces can lead to unacceptable intraocular lens (IOL), power calculation results after corneal refractive surgery, and errors during the calculation of toric IOLs. Objectives: This study aimed to determine the percentage of contribution of the magnitude of posterior corneal astigmatism (PCA) to total corneal astigmatism (TCA) and to investigate the correlation between anterior corneal astigmatism (ACA), PCA, and TCA. Methods: A prospective cross-sectional study including 55 subjects aged 18 – 31 years old and divided into 3 groups based on spherical equivalent (SE), Emmetropia, Hyperopia, and Myopia were included. All subjects underwent full ophthalmological examinations and corneal topography. ACA and PCA were evaluated. TCA was computed by the addition of the ACA and PCA using vector analysis. The percentage of contribution of the PCA to the magnitude of the TCA and the correlation between ACA, PCA, and TCA were calculated. Results: All subjects had anterior corneal with the rule (WTR) astigmatism. The contribution of PCA to TCA for all subjects in 3 groups (Emmetropia, Hyperopia, and Myopia) was 35%, 37%, and 37%, respectively, with P &gt; 0.05, which was not statistically significant. There was a correlation between ACA, PCA, and TCA in all study groups. Conclusion: TCA is composed of both corneal surfaces, and PCA impacts the outcomes of refractive surgeries for correcting astigmatism and in toric intraocular lens (IOL) calculation when just based on the data of the anterior corneal surface.

Intraocular Lenses for Cataract Surgery

What Is the Issue?&#x0D; &#x0D; 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.&#x0D; Premium lenses, including lenses to correct astigmatism (called toric lenses), are available but may not be covered by public or private health plans.&#x0D; 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.&#x0D; &#x0D; What Did We Do?&#x0D; &#x0D; 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.&#x0D; 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.&#x0D; &#x0D; What Did We Find?&#x0D; &#x0D; 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.&#x0D; 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).&#x0D; 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.&#x0D; 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.&#x0D; 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.&#x0D; &#x0D; What Does it Mean?&#x0D; &#x0D; 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.&#x0D; 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.&#x0D; 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.&#x0D;