Consensus on the management of astigmatism in cataract surgery

Assessment of the refractive outcomes of patients with regular corneal astigmatism implanted with high-power toric intraocular lenses

BACKGROUND

To describe the refractive outcomes of eyes with high regular corneal astigmatism undergoing age-related cataract surgery.

METHODS

Astigmatic patients who underwent cataract surgery with implantation of high-power XY1AT HOYA® toric lenses (IOLs) (≥ T5) between March 2020 and June 2022 were included. Patients were divided into 2 groups based on the type of Total Corneal Astigmatism (TCA) used for the toric IOL calculation: group 1 = TCATK- 700 (TCA measured by the Iol Master 700®) and group 2 = TCAAK- 700 (TCA estimated from the anterior keratometry of the Iol Master 700® and using the Abulafia-Koch regression). The best-uncorrected (UDVA) and corrected (CDVA) distance visual acuity, subjective spherical equivalent (SSEq) and subjective residual cylinder (SRC) were assessed at 1 month. The predictability (centroid [CEPA] and mean absolute error in predicted astigmatism [MAEPA]) of the 2 TCA assessment methods was analyzed.

RESULTS

96 eyes of 74 patients were included. In the whole cohort, the UDVA was 0.14 ± 0.19 logMAR, the CDVA was 0.04 ± 0.07 logMAR. Postoperative SSEq was - 0.24 ± 0.53D. Postoperative SRC was - 0.48 ± 0.56D. The UDVA, SSEq and SRC did not significantly differ between groups. The MAEPA was significantly better with TCAAK-700 compared to TCATK-700: 0.58 ± 0.52D versus 0.65 ± 0.55D (p = 0.01). No significant difference was observed for the CEPA (p(x) = 0.09, p(y) = 0.19).

CONCLUSIONS

XY1AT HOYA® toric IOLs are a very good alternative even in case of high toricity. Residual astigmatism predictability is high, it would be better with TCAAK- 700. This data should be confirmed with a larger sample of patients.

Effect of low-degree astigmatism on the objective visual quality

AIM

To evaluate the effect of low-degree astigmatism on objective visual quality through the Optical Quality Analysis System (OQAS).

METHODS

This study enrolled 46 participants (aged 23 to 30y, 90 eyes) with normal or corrected-to-normal vision. The cylindrical lenses (0, 0.5, 0.75, 1.0, and 1.25 D) were placed at the axial direction (180°, 45°, 90°, and 135°) in front of the eyes with the best correction to form 16 types of regular low-degree astigmatism. OQAS was used to detect the objective visual quality, recorded as the objective scattering index (OSI), OQAS values at contrasts of 100%, 20%, and 9% predictive visual acuity (OV100%, OV20%, and OV9%), modulation transfer function cut-off (MTFcut-off) and Strehl ratio (SR). The mixed effect linear model was used to compare objective visual quality differences between groups and examine associations between astigmatic magnitude and objective visual quality parameters.

RESULTS

Apparent negative relationships between the magnitude of low astigmatism and objective visual quality were observed. The increase of OSI per degree of astigmatism at 180°, 45°, 90°, and 135° axis were 0.38 (95%CI: 0.35, 0.42), 0.50 (95%CI: 0.46, 0.53), 0.49 (95%CI: 0.45, 0.54) and 0.37 (95%CI: 0.34, 0.41), respectively. The decrease of MTFcut-off per degree of astigmatism at 180°, 45°, 90°, and 135° axis were -10.30 (95%CI: -11.43, -9.16), -12.73 (95%CI: -13.62, -11.86), -12.75 (95%CI: -13.79, -11.70), and -9.97 (95%CI: -10.92, -9.03), respectively. At the same astigmatism degree, OSI at 45° and 90° axis were higher than that at 0° and 135° axis, while MTFcut-off were lower.

CONCLUSION

Low astigmatism of only 0.50 D can significantly reduce the objective visual quality.

Insights into the rotational stability of toric intraocular lens implantation: diagnostic approaches, influencing factors and intervention strategies

Toric intraocular lenses (IOLs) have been developed to enhance visual acuity impaired by cataracts and correct corneal astigmatism. However, residual astigmatism caused by postoperative rotation of the toric IOL is an important factor affecting visual quality after implantation. To decrease the rotation of the toric IOL, significant advancements have been made in understanding the characteristics of toric IOL rotation, the factors influencing its postoperative rotation, as well as the development of various measurement techniques and interventions to address this issue. It has been established that factors such as the patient's preoperative refractive status, biological parameters, surgical techniques, postoperative care, and long-term management significantly impact the rotational stability of the toric IOL. Clinicians should adopt a personalized approach that considers these factors to minimize the risk of toric IOL rotation and ensure optimal outcomes for each patient. This article reviews the influence of various factors on toric IOL rotational stability. It discusses new challenges that may be encountered to reduce and intervene with rotation after toric IOL implantation in the foreseeable future.

Combined Femtosecond Laser-Assisted Keratotomy and Cataract Surgery for Enhancing Refractive Outcomes. An Indonesian Case Study

Purpose

We evaluate the reduction of corneal astigmatism and the improvement of visual outcomes of this surgical method in the Indonesian population. We also assess the accuracy and predictability of using femtosecond laser astigmatic keratotomy (FLAK) combined with cataract surgery.

Patients and Methods

In a retrospective study, a total of 275 subjects (78 with against-the-rule (ATR) astigmatism, 178 with with-the-rule (WTR) astigmatism, and 19 with oblique (OBL) astigmatism) with preexisting corneal astigmatism ranging from 0.75D to 3.00D underwent FLAK. All subjects completed a 3-month follow-up. The femtosecond laser used for creating paired AK 2.2 mm, primary incision, and paracentesis incision was the FEMTO Z8 NEO from Ziemer Ophthalmic System, Switzerland. The surgical approach was guided by the "NAPA" nomogram.

Results

The reduction in postoperative astigmatism was 56.90% for the WTR group, 49.46% for the ATR group, and 47.33% for the oblique group. A significant reduction in astigmatism was observed at the 1-week, 1-month, and 3-month follow-up intervals in both the WTR and ATR groups. The reduction in astigmatism was more favorable in cases of moderate astigmatism within the WTR group, as compared to the ATR and oblique groups. Postoperative astigmatism reduction was found to be more predictable in the right eye than in the left eye.

Conclusion

The combination of FLAK can be considered as a potential method for reducing corneal astigmatism ranging from 1.00D to <3.00D. The highest reduction was observed in the WTR group, along with a higher rate of intended correction without astigmatism meridian shift in the right eye for the WTR group. However, factors such as cyclotorsion resulting from the surgical technique, alignment of docking, incision length, and preoperative astigmatism need to be taken into account for further enhancement and predictability of astigmatism reduction with this method.

Outcomes of toric intraocular lens realignment surgery done using slit-lamp method and wavefront aberrometry method

Purpose

To compare the slit-lamp method and wavefront aberrometry method based on outcomes of toric realignment surgeries.

Settings

Tertiary care ophthalmic hospital.

Design

Retrospective study.

Methods

This study included all eyes undergoing toric intraocular lens (TIOL) realignment surgery between January 2019 and December 2021 for which TIOL axis assessment by slit-lamp method and wavefront aberrometry method was available. Data were retrieved from electronic medical records, and we documented demographics, uncorrected visual acuity (UCVA), subjective refraction, and TIOL axis by slit-lamp and wavefront aberrometry methods on postoperative day 1 and day 14. In patients with misalignment, TIOL was realigned to the original position in group 1 (27 patients) and to an axis based on calculations provided by wavefront aberrometer in group 2 (25 patients). Post-realignment surgery, UCVA, subjective refraction, and TIOL axis by slit-lamp and wavefront aberrometry methods were assessed and analyzed.

Results

We analyzed 52 eyes and found that the mean preoperative misalignment with the slit-lamp method (44.9° ±20.0°) and wavefront aberrometry (47.1° ±19.5°) was similar. The corresponding degrees of misalignment post-TIOL repositioning surgeries were 5.2° ±5.2° (slit-lamp method) and 4.7° ±5.1° (wavefront aberrometry) (P = 0.615). Both groups showed significant improvement in median log of minimum angle of resolution (logMAR) UCVA and reduction in median refractive cylinder.

Conclusions

Slit-lamp method is as good as wavefront aberrometer method to assess TIOL axis. Toric realignment surgery is found to be safe, and realigning TIOL based on either slit-lamp method or wavefront aberrometer method equally improved UCVA and decreased residual refractive cylinder.

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

PURPOSE

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.

METHODS

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.

RESULTS

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 43 days to 4.5 years. 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.

CONCLUSION

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.

The Current Burden and Future Solutions for Preoperative Cataract-Refractive Evaluation Diagnostic Devices: A Modified Delphi Study

Purpose

To obtain consensus on the key areas of burden associated with existing devices and to understand the requirements for a comprehensive next-generation diagnostic device to be able to solve current challenges and provide more accurate prediction of intraocular lens (IOL) power and presbyopia correction IOL success.

Patients and Methods

Thirteen expert refractive cataract surgeons including three steering committee (SC) members constituted the voting panel. Three rounds of voting included a Round 1 structured electronic questionnaire, Round 2 virtual face-to-face meeting, and Round 3 electronic questionnaire to obtain consensus on topics related to current limitations and future solutions for preoperative cataract-refractive diagnostic devices.

Results

Forty statements reached consensus including current limitations (n = 17) and potential solutions (n = 23) associated with preoperative diagnostic devices. Consistent with existing evidence, the panel reported unmet needs in measurement accuracy and validation, IOL power prediction, workflow, training, and surgical planning. A device that facilitates more accurate corneal measurement, effective IOL power prediction formulas for atypical eyes, simplified staff training, and improved decision-making process for surgeons regarding IOL selection is expected to help alleviate current burdens.

Conclusion

Using a modified Delphi process, consensus was achieved on key unmet needs of existing preoperative diagnostic devices and requirements for a comprehensive next-generation device to provide better objective and subjective outcomes for surgeons, technicians, and patients.

Non-pathologic components are associated with reduced visual acuity in myopes after spectacle correction

Purpose

To find the association between reduced best-corrected visual acuity and non-pathologic components after optical correction in individuals with low to high myopia.

Methods

Myopic children under 16 years of age were reviewed using electronic medical records and the following data were extracted and recorded: participant's age, gender, uncorrected visual acuity (UCVA), manifest refraction, and best corrected visual acuity (BCVA). Spherical equivalent and cylinder were classified into low, moderate, and high categories based on the magnitude range. Similarly, astigmatism was defined into with-the-rule, against-the-rule, and oblique based on the location of the steepest meridian. Reduced BCVA was defined when the decimal visual acuity was less than 0.66 (equivalent to Snellen's acuity of 6/9 or 20/30). Logistic regression was performed to test the factors associated with reduced visual acuity after optical correction in the absence of myopic pathologic changes. Statistical significance was considered if P < 0.05.

Results

Overall 44.9% (N = 242/538) of myopes had reduced best-corrected visual acuity (BCVA) and none of the patients had pathologic myopic lesions. Using logistic regression, we found that high spherical refraction (OR 27.98, 95% CI 14.43-54.25, P < 0.001) and moderate spherical refraction (OR 5.52, 95% CI 2.56-11.91, P < 0.001) were significantly associated with reduced best corrected visual acuity despite any pathological lesions. Additionally, oblique and ATR astigmatism were associated with reduced visual acuity in myopic children with (OR 2.05, 95% CI 0.77-5.42) and (OR 1.59, 95% CI 0.82-3.08).

Conclusion

Higher magnitude of refractive error components causes reduced visual acuity in the absence of pathologic changes.

Impact of Total Corneal Astigmatism Estimated With the Abulafia-Koch Formula Versus Measured With a SS-OCT Biometer on the Refractive Outcomes of a Toric Intraocular Lens in Cataract Surgery

PURPOSE

To compare the impact of total corneal astigmatism (TCA) estimated with the Abulafia-Koch formula (TCA^ABU) versus measured by Total Keratometry (TK), swept-source optical coherence tomography (OCT) coupled with telecentric keratometry (TCA^TK) on the refractive outcomes after cataract surgery with toric intraocular lens (IOL) implantation.

METHODS

Two hundred one eyes of 146 patients who underwent cataract surgery with toric IOL implantation (XY1AT; HOYA Corporation) were included in this single-center, retrospective study. For each eye, TCA^ABU (estimated from the anterior keratometry values measured with the IOLMaster 700 [Carl Zeiss Meditec AG]) and TCA^TK (measured using TK IOLMaster 700) were entered into the HOYA Toric Calculator. Patients were operated on based on TCA^ABU. For each eye, centroid and mean absolute error in predicted residual astigmatism (EPA) were calculated according to TCA used (TCA^ABU or TCA^TK). The cylinder power and the axis of the posterior chamber IOL were compared.

RESULTS

The mean uncorrected distance visual acuity was 0.07 ± 0.12 logMAR, the mean spherical equivalent was 0.11 ± 0.40 D, and mean residual astigmatism was 0.35 ± 0.36 D. Mean centroid EPA was 0.28 D at 132° with TCA^ABU and 0.35 D at 148° with TCA^TK (P(x) < .001; P(y) < .01). Mean absolute EPA was 0.46 ± 0.32 D with TCA^ABU and 0.50 ± 0.37 D with TCA^TK (P < .01). In the with-the-rule astigmatism subgroup, a deviation from the target of less than 0.50 D was achieved in 68% of eyes with TCA^ABU versus 50% of eyes with TCA^TK. The proposed posterior chamber IOL was different depending on the calculation methods used in 86% of cases.

CONCLUSIONS

Both calculation methods showed excellent results. However, the predictability error was significantly reduced when TCA^ABU was used compared to TCA^TK measured with the IOLMaster 700 in the whole cohort. Finally, TCA was overestimated by TK in the with-the-rule astigmatism subgroup. [J Refract Surg. 2023;39(3):171-179.].

Epidemiology and Burden of Astigmatism: A Systematic Literature Review

SIGNIFICANCE

This is the first literature review to report the epidemiology, patient burden, and economic burden of astigmatism in the general adult population. The unmet needs of astigmatism patients with coexisting ocular conditions (cataract, glaucoma, dry eye, presbyopia, or macular degeneration) and risks associated with untreated astigmatism are also reviewed and reported.

PURPOSE

This study aimed to identify, report, and summarize the published literature on epidemiology, patient burden, and economic burden of astigmatism using a systematic literature review.

METHODS

MEDLINE, EMBASE, and Cochrane Library databases were searched (January 1996 to May 2021). Search results were limited to the English language. Proceedings (2018 to 2021) from ophthalmology congresses were searched along with gray literature using the Google Scholar platform.

RESULTS

The literature search yielded 6804 citations, of which 125 met the inclusion criteria (epidemiology, 68; patient burden, 60; economic burden, 6). Astigmatism prevalence in the general population varied from 8 to 62%, with higher rates in individuals 70 years or older. The prevalence of with-the-rule astigmatism was higher in individuals 40 years or younger, whereas rates of against-the-rule and oblique astigmatism increased with age. Astigmatic patients experienced decreased vision quality, increased glare (53 to 77%), haloes (28 to 80%), night-time driving difficulties (66%), falls, and spectacle dependence (45 to 85%). Astigmatic patients performed vision-related tasks slower (1 D, 9% slower; 2 D, 29% slower) and made more errors (1 D, 38% more errors; 2 D, 370% more errors) compared with fully corrected individuals. In cataract patients with astigmatism, the annual mean per-patient productivity loss costs ranged from €55 ($71) to €84 ($108), and mean informal care costs ranged from €30 ($39) to €55 ($71) with a mean of 2.3 to 4.1 hours spent on informal care.

CONCLUSIONS

Uncorrected astigmatism decreases patients' vision-related quality of life, decreases productivity among working-age adults, and poses an economic burden on patients and their families.

The prevalence of refractive errors in college students in Israel

PURPOSE

To determine the prevalence of refractive errors in Jewish and Arab college students in Israel and associations with ethnicity and sex.

METHODS

In this retrospective cross-sectional study, first-year college students underwent non-cycloplegic autorefraction and answered a questionnaire to assess age, sex, and self-identified ethnicity. Spherical equivalent refractive error (SER) was calculated, and the prevalence of hyperopia (>+0.50 Diopter, D), emmetropia (>-0.50 to +0.50 D), myopia (≤-0.50D, low ≤-0.50 to >-3.0D, moderate <-3.0 to >-6.0D, high ≤-6.0D), and astigmatism (>0.50D) were determined. Groups were compared using Chi-square or Fisher test. Univariate and multivariate analyses were conducted to identify factors associated with refractive errors.

RESULTS

Participants (n = 807) had a mean age of 22.1 ± 2.6 years (range: 17-30 years) and SER of -1.7 ± 2.2D (range: -13.3 to +5.7D). The prevalence and 95% confidence internal of myopia was 66.3% (63.0-69.6). Jewish students had a higher prevalence than Arab students for myopia (69.2% vs 60.3%), moderate (18.5% vs 12.2%) and high myopia (5.9% vs 1.9%) and astigmatism (51.4% vs 43.9%, p<0.05 for all), but not low myopia or hyperopia. Females had a higher prevalence of myopia than males (68.1% vs 58.7%, p<0.03). Jewish ethnicity was associated with myopia (OR=1.48, p = 0.01) and moderate myopia (OR=1.72, p = 0.01), and studying optometry was associated with moderate myopia (OR=1.63, p = 0.02). Sex and age were not associated with myopia.

CONCLUSION

Myopia prevalence in Israeli college students is high, showing associations with Jewish, but not Arab, ethnicity, suggesting that ethnic factors may play a role in the refractive differences between Arabs and Jews.

Do limbal relaxing incisions during cataract surgery still have a role?

BACKGROUND

Though Limbal Relaxing Incisions (LRI) were used widely to correct pre-existing corneal astigmatism during cataract surgery, they have been replaced recently with the more expensive methods like the use of toric Intra Ocular Lenses (IOL) and femtosecond during cataract surgery. We conducted our study to re-evaluate the role of (LRI) in correcting pre-existing moderate corneal astigmatism during cataract surgery in settings where other options are neither available nor affordable.

METHODS

Retrospective analysis of all consecutive cases of LRI performed by a single surgeon at the time of cataract surgery to correct moderate corneal astigmatism (1.5-3D) in a community hospital over a period of 6 months. Corneal astigmatism, uncorrected distance visual acuity (UDVA) and best corrected distance visual acuity (CDVA) were recorded pre-operatively, 4 weeks and 3 months post-operatively. Data on age, intraocular lens (IOL) power, predictive refraction and post-operative spherical equivalent was also collected and analyzed. The number and position of LRI was determined based on the pre-existing corneal astigmatism using online calculator.

RESULTS

29 eyes of 25 patients with the mean age of 73.6 years (range: 46 to 90 years) and corneal astigmatism between 1.5 to 3D were included. Statistically significant reduction in the mean corneal astigmatism was recorded from 2.05 ± 0.45D preoperatively to 0.85 ± 0.56D postoperatively (P < 0.0001). All eyes showed reduction in astigmatism; 83% of eyes had < 1.0D post-operatively and 66% of eyes had < 0.75D. UDVA of 6/9 or better was recorded in 80% of eyes post-operatively (CDVA of 6/9 or better in 100%). The spherical equivalent was within 1.0D of the predictive refraction postoperatively in nearly all eyes (97%) and within 0.5D in 86% of the eyes. There were no peri-operative or post-operative complications were recorded in any case.

CONCLUSION

Combining LRI and cataract surgery to address moderate degrees of corneal astigmatism is a safe, reliable and predictable option especially in areas where more expensive methods such as toric IOL or excimer laser are not available or affordable. LRI has no significant effect on the spherical equivalent and is an excellent tool in reducing patient's spectacle dependence.

Ocular findings in 22q11.2 deletion syndrome: A systematic literature review and results of a Dutch multicenter study

The 22q11.2 deletion syndrome (22q11.2DS) is a multisystem disorder with an estimated prevalence of 1:3000 live births. Manifestations show a marked variability in expression and include speech‐ and language delay, intellectual disability, and neuropsychiatric disorders. We aim to provide an overview of ocular findings in 22q11.2DS in order to optimize recommendations for ophthalmic screening. We combined results from a systematic literature review with results from a multicenter cross‐sectional study of patients with 22q11.2DS who were assessed by an ophthalmologist. Our systematic literature search yielded four articles, describing 270 patients. We included 132 patients in our cross‐sectional study (median age 8.9 [range 0–56] years). Most reported ocular findings were retinal vascular tortuosity (32%–78%), posterior embryotoxon (22%–50%), eye lid hooding (20%–67%), strabismus (12%–36%), amblyopia (2%–11%), ptosis (4%–6%), and refractive errors, of which hyperopia (6%–48%) and astigmatism (3%–23%) were most common. Visual acuity was (near) normal in most patients (91%–94%). Refractive errors, strabismus, and amblyopia are treatable conditions that are frequently present in patients with 22q11.2DS and should be corrected at an early stage. Therefore, in 22q11.2DS, we recommend ophthalmic and orthoptic screening at the age of 3 years or at diagnosis, and a low‐threshold referral in adults.

Calculation of Toric Intraocular Lens Power with the Barrett Calculator and Data from Three Keratometers

Aim

To investigate the interdevice agreement for differences in toric power calculated using data on anterior corneal astigmatism obtained with corneal topography/ray-tracing aberrometry (iTrace), partial coherence interferometry (IOLMaster 500), and Scheimpflug imaging (Pentacam).

Methods

The analysis included 101 eyes (101 subjects) with regular astigmatism. The main outcome measures were corneal cylinder power, axis of astigmatism, and keratometry values. Toricity and toric IOL power were calculated using the online Barrett toric calculator. Interdevice agreement for measurement and calculation was assessed using a paired sample t-test and a nonparametric test.

Results

Significant interdevice differences were noted in the magnitude of astigmatism and flat, steep, and mean keratometry values between iTrace and IOLMaster (all P < 0.01); in flat, steep, and mean keratometry values (all P < 0.001) but not in the magnitude of astigmatism (P=0.325) between iTrace and Pentacam; and in the magnitude of astigmatism and steep and mean keratometry values (all P < 0.01) but not in flat keratometry values (P=0.310) between IOLMaster and Pentacam. The toric IOL power calculated using data from the three devices showed the following trend: iTrace > IOLMaster (0.49 ± 0.36, P < 0.001) and Pentacam (0.39 ± 0.42, P < 0.001) and Pentacam was <IOLMaster (-0.10 ± 0.39, P=0.009). There were differences in toricity calculated using data from the three devices (P=0.004).

Conclusions

Differences in toric IOL power and toricity calculated using anterior keratometry data from iTrace, IOLMaster 500, and Pentacam should be noted in clinical practice.

Astigmatism Management with Astigmatism-Correcting Intraocular Lens Using Two Toric Calculators - A Comparative Case Series

Background

To compare refractive outcomes after phacoemulsification and toric IOL implantation using two different toric calculators for initial astigmatism assessment in a real-world setting.

Methods

This was a retrospective, comparative, interventional case series. Patients over 30-year-old who underwent phacoemulsification and toric IOL implantation (AcrySof^® Toric IOL) by the same surgeon between 2017 and 2018 were included. Eyes with irregular astigmatism, previous corneal refractive surgery, intraocular surgery, corneal pathology, macular pathology and pupil abnormalities were excluded. IOL toricity was determined by using a calculator provided by the AcrySof Toric calculator before 2018 and Barrett Toric Calculator after 2018. Patient demographics, corneal topography, vector and preoperative and postoperative refraction were collected and analyzed at three months postoperative.

Results

Thirty-two eyes of 32 patients were included in the final analysis. 0.1D for surgically induced astigmatism was used. Group 1 included 14 eyes assessed with the original (AcrySof) toric IOL calculator, and group 2 included 18 eyes assessed with the Barrett toric IOL calculator. In group 1, postoperative astigmatism less than −1.00D, −0.75 D, and −0.5D was achieved in 88.2%, 76.1% and 53.7% of eyes, respectively, while, in group 2, 89% eyes achieved postoperative residual astigmatism less than 0.5D and all eyes achieved postoperative residual astigmatism less than 0.75D. The proportion of patients with lower postoperative astigmatism was significantly higher in Group 2 (p< 0.05 by chi-square test), a pattern that still held when we divided patients into multiple groups. Vector analysis with the Alpins methods also supported better outcomes in the Barrett group (0.71 D vs 0.35 D).

Conclusion

The Barrett Toric calculator resulted in better results in the prediction of residual astigmatism than original (AcrySof) toric calculators.

Refractive Status in Eyes Implanted with Toric and Nontoric Intraocular Lenses during Combined Cataract Surgery and Microhook Ab Interno Trabeculotomy

Purpose

To compare the refractive status between eyes implanted with toric and nontoric intraocular lenses (IOLs) during combined cataract surgery and microhook ab interno trabeculotomy (μLOT), a minimally invasive glaucoma surgery (MIGS).

Methods

Twenty eyes of 20 patients who had open-angle glaucoma, cataract, and preexisting regular corneal astigmatism exceeding 1.5 diopters (D) and underwent combined μLOT and phacoemulsification were recruited retrospectively. Ten eyes were implanted with a toric IOL and 10 eyes with a nontoric IOL. The primary outcomes were the uncorrected visual acuity (UCVA) and refractive cylinder at 3 months postoperatively.

Results

The mean UCVA of the toric IOL group (logarithm of the minimum angle of resolution (logMAR), 0.23 ± 0.25) was significantly better than that of the nontoric IOL group (logMAR, 0.45 ± 0.26) at 3 months postoperatively (p < 0.05). The mean absolute residual refractive cylinder of the nontoric IOL group (2.25 ± 0.62 D) was significantly greater than that of the toric IOL group (1.30 ± 0.68 D) (p < 0.05). Postoperatively, 60% of eyes in the toric IOL group and 10% in the nontoric IOL group had an absolute refractive astigmatism level of 1.5 D or less. Surgically induced astigmatism (0.77 ± 0.43 D for toric group and 0.60 ± 0.32 D for nontoric group) and IOP reduction (33.9 ± 15.6% for toric group and 29.4 ± 11.7% for nontoric group) were not different between groups.

Conclusions

Use of toric IOL during combined cataract surgery and μLOT is possible and better than not, but physician should prevent their patient of persisting residual astigmatism. The study was registered at https://www.umin.ac.jp/, and the clinical trial accession number is https://clinicaltrials.gov/ct2/show/UMIN000043141.

Randomized trial comparing visual outcomes of toric intraocular lens implantation using manual and digital marker

Purpose:

The aim of this study was to compare the visual outcome of participants undergoing toric intraocular lens (IOL) implantation after cataract extraction using manual marking versus digital marking for intraoperative guidance.

Methods:

Randomized controlled trial of participants with cataract and corneal astigmatism of 1.00 D-4.50 D. The eyes were grouped into manual marking (Group 1) and digital marking (Group 2). Preoperative Uncorrected distance visual acuity (UDVA), Corrected distance visual acuity (CDVA), and corneal astigmatism were determined. IOL power and axis of alignment were determined using Barrett toric calculator. Eyes were marked by bubble marker and Mendez ring in group 1 and by VERION (Alcon, Fort Worth, Texas) digital overlay in Group 2. Postoperatively, UDVA, CDVA, residual refractive cylinder and IOL misalignment were determined (iTrace system, Tracey technologies) at 1 week, 6 weeks, and 3 months.

Results:

A total of 61 eyes of 50 participants, 31 in Group 1 and 30 in Group 2, were studied. The mean postoperative cylindrical error was 0.50 ± 0.39 D in Group 1 and 0.29 ± 0.34 D in Group 2 (P = 0.03). 67.74% (n = 21) and 93.55% (n = 29) eyes achieved a residual astigmatism of ≤0.50 D and ≤1.00 D, respectively, in Group 1, whereas 83.33% (n = 25) and 100% (n = 30) eyes achieved a residual astigmatism of ≤0.50 D and ≤1.00 D, respectively, in Group 2 at 3 months postoperatively. Toric IOL misalignment was 4.71 ± 3.12° in Group 1 and 4.03 ± 2.99° in Group 2 (P = 0.39).

Conclusion:

Accurate manual marking and digital marking are equally effective guides for toric IOL alignment, intraoperatively.

Clinical evaluation of toric intraocular lens implantation based on iTrace wavefront keratometric astigmatism

Background

Currently, there is no standard technique for determining corneal astigmatism. The iTrace wavefront aberrometry of cornea calculated steep power and axis based on the best Zernike mathematical fit from all topo data within 4 mm circle. It was supposed to be more accurate than iTrace simulated keratometry which was calculated based on only 4 points on the circle of 3 mm. This aim of this study was to evaluate visual outcomes and rotational stability after toric intraocular lens (IOL) implantation using the wavefront aberrometry of the cornea with iTrace.

Setting: Single site in China, Shanxi Eye Hospital, Shanxi, China.

Design: Prospective case series.

Methods

The study included 85 eyes of 63 patients undergoing phacoemulsification and toric IOL implantation. The IOL power and cylinders were chosen with the help of the iTrace toric planning program using wavefront keratometric astigmatism. Astigmatic changes were assessed using Alpins vector method over a 3-month follow-up period.

Results

Preoperative mean corneal topographic astigmatism was 1.91 diopters (D) ± 0.69 (standard deviation). Postoperative mean refractive astigmatism decreased significantly to 0.48 D ± 0.34. Surgical induced astigmatism was 1.73 D ± 0.77 and the mean correction index was 0.89 ± 0.22, showing a slight undercorrection. The proportion of astigmatism ≤0.50 D increased from 0 to 71.8% postoperatively.

Conclusions

This is the first study on evaluation of clinical outcomes of toric IOL implantation in corneal astigmatism patients using iTrace wavefront keratometric readings. The findings show that use of iTrace built-in toric calculator is safe and effective for planning toric IOL surgery for wavefront keratometric astigmatism.

Trial registration

Current Controlled Trials ISRCTN94956424, Retrospectively registered (Date of registration: 05 February 2020).

Impact of Thermal Pulsation Treatment on Astigmatism Management and Outcomes in Meibomian Gland Dysfunction Patients Undergoing Cataract Surgery

Purpose

This study aimed to assess the effects of thermal pulsation system (TPS) treatment on astigmatism management in meibomian gland dysfunction (MGD) patients undergoing cataract surgery.

Patients and Methods

This single-center pilot study included 25 eyes of 23 patients who had visually significant cataract and concomitant MGD-associated dry eye in at least 1 eye and were willing to undergo TPS treatment and wait for at least 6 weeks for tear film stabilization prior to cataract surgery. Post-TPS keratometric readings were used for presurgical planning, and the actual postoperative residual refractive astigmatism (RRA) was recorded. Pre-TPS keratometry was used to mathematically simulate the RRA that would have been obtained from the lens choice and astigmatism management without TPS treatment.

Results

Following TPS treatment, the magnitude of astigmatism increased in 52% of eyes, decreased in 24%, and remained unchanged in 24%. Correspondingly, astigmatism treatment modality changed in 68% of eyes after tear film stabilization with TPS treatment. The type of astigmatism management increased (ie, shifted from no treatment to LRI or LRI to toric IOL) in 25% of eyes and decreased in 8%. Actual RRA ≤0.5 D was achieved in 76% of eyes, compared to simulated RRA ≤0.5 D in 40% of eyes (p=0.004).

Conclusion

Stabilization of the tear film with TPS treatment resulted in less RRA than if pre-TPS keratometric readings had been used to determine the astigmatism management method and toric IOL power and axis.

Astigmatism Management with Intraocular Lens Surgery

Corneal astigmatism is common. More than 40% of patients undergoing cataract surgery have 1 diopter (D) power or more of astigmatism, which left untreated is visually significant. Because toric intraocular lenses (IOLs) are available, the current standard of care is to offer treatment of astigmatism at the time of cataract surgery. PubMed, MEDLINE, Embase databases, and the Cochrane Library were systematically searched from inception to October 2019. Search words included astigmatism, corneal astigmatism, toric IOLs, alignment, and IOL calculation. Studies evaluated included review articles regarding the origin and history of astigmatism, the diagnosis and management of the disease, and the history of surgical management options for astigmatism. Other studies evaluated in this review included clinical trials, meta-analyses, and retrospective analysis of surgical refractive outcomes. Prediction of refractive outcomes was evaluated with a review of IOL calculators and their use in lens prediction for cataract surgery. Evaluation of these articles also showed improved uncorrected visual acuity with the use of toric IOLs in patients undergoing cataract surgery. New diagnostic technology, new toric IOLs, updated lens formulas, intraoperative guidance, and advanced imaging technology and software have contributed to improvements in the surgical correction of astigmatism.

When is refraction stable following routine cataract surgery? A systematic review and meta-analysis

PURPOSE

We systematically reviewed the literature to investigate when refraction is stable following routine cataract surgery implanting monofocal intraocular lenses. Current advice recommends obtaining new spectacles 4-6 weeks following surgery. Due to advancements in surgical techniques, we hypothesised that refractive stability would be achieved earlier, which could have major short-term improvements in quality of life for patients.

METHODS

Medline, CINAHL, AMED, Embase, Web of Science and the Cochrane Library were searched with key words chosen to find articles, which assessed refraction following uncomplicated cataract surgery. Citation chains and the reference lists of all included papers were searched. Unpublished literature was identified using OpenGrey (www.opengrey.eu). The review considered studies that measured refraction at regular intervals following surgery until stability was achieved.

RESULTS

The search identified 6,680 papers. Two reviewers independently screened the abstracts and nine papers were found to fit the criteria, of which five were included in the meta-analysis. The quality of the papers was evaluated using the Methodological Index for Non-Randomised Studies (MINORS) instrument. Meta-analysis of 301 patients' data of spherical, cylindrical and spherical equivalent correction were performed using Review Manager 5 (RevMan 5.3) (https://revman.cochrane.org/). Refraction at 1-week versus the gold standard of 4-weeks showed no significant difference for sphere data (effect size and 95% confidence interval of; ES = 0.00, 95% CI: -0.17, 0.17; p = 1.00), cylindrical data (ES = +0.06; 95% CI: -0.05, 0.17; p = 0.31), and spherical equivalent (ES = -0.01; 95% CI: -0.12, 0.10; p = 0.90). Heterogeneity was non-significant (I²  < 25%) for all refractive elements. Data were similar for 2- versus 4-weeks post-surgery. Acquired data from one study highlighted a small number of patients with very unstable cylindrical corrections at 1-week post-operatively.

CONCLUSIONS

No statistical difference was found when comparing sphere, cylindrical and spherical equivalent values at 1- and 4-weeks post cataract surgery. This suggests that new glasses could be provided 1-week after surgery. However, from a clinical perspective, a small number of patients (~7%) from an acquired dataset (N = 72) showed very unstable cylindrical corrections at 1-week. Further work is needed to determine why this is the case and how these patients can be detected.

Agreement between IOLMaster® 500 and Pentacam® HR for keratometry assessment in type 2 diabetic and non-diabetic patients

AIM

To evaluate inter-device agreement of anterior keratometry obtained by the IOLMaster^® 500 and Pentacam^® HR in type 2 diabetic and non-diabetic patients.

METHODS

Corneal measurements were sequentially performed in 60 diabetes mellitus (DM) and 48 age and sex-matched controls undergoing cataract surgery. Variables recorded included flat and steep keratometry, mean keratometry (K_m), astigmatism magnitude, axis location, J0 and J45 components. Bland-Altman plots and intraclass correlation coefficients were used for examination of agreement. Subgroup analyses were performed for astigmatism magnitude, diabetes duration, hemoglobin A1c (HbA1c) levels and diabetic retinopathy (DR) stage.

RESULTS

Agreement for K_m and astigmatism magnitude were considered good and moderate, with 95% limits of agreement (LoA) of -1.09 to 1.23 diopters (D) and -0.83 to 0.86 D in DM group, respectively; and -0.59 to 0.72 D and -0.98 to 0.75 D in non-DM group, respectively. In contrast, the 95% LoA for corneal axis exceeded the clinically relevant margins in both groups. In the total sample, only 41 eyes (38%) had a smaller than 5-degree difference. Diabetes duration, HbA1c levels and DR stage were not found to significantly affect agreement. Logistic regression showed that higher corneal power (P=0.021) and astigmatism magnitude (P=0.011) were associated with a decreased risk of having a difference in axis location greater than 10-degrees.

CONCLUSION

In both groups, IOLMaster and Pentacam agree well for corneal power and moderately for astigmatism. However, axis location disagreement is frequent in eyes with flatter corneas and small amounts of astigmatism.

Management of Cataract in Patients with Irregular Astigmatism with Regular Central Component by Phacoemulsification Combined with Toric Intraocular Lens Implantation

Purpose

To evaluate visual acuity (VA) and refractive status in patients with cataract and irregular astigmatism with a regular central component after phacoemulsification with implantation of a toric intraocular lens (IOL).

Methods

Patients with cataract associated with irregular astigmatism with a regular central component were enrolled. All patients underwent phacoemulsification and toric IOL implantation. Postoperative visual acuity, residual astigmatism, toric IOL rotation, higher-order aberration, and objective and subjective visual quality were measured 3 months after surgery.

Results

Twenty-three eyes were included in the study. The logMAR corrected and uncorrected distance visual acuity values were decreased at 3 months postoperatively (p  <  0.005). The preoperative average corneal astigmatism and postoperative residual astigmatism were 1.15–6.97 D (1.99 ± 1.26 D) and 0–2.75 D (0.65 ± 0.57 D), respectively. The average IOL rotation was 3.17 ± 2.01°. Some objective indicators of visual quality, including the modulation transfer function (p  <  0.05), Strehl ratio (p  <  0.005), 100% VA (p  <  0.005), 20% VA (p  <  0.005), and 9% VA (p  <  0.005), were significantly higher than the corresponding preoperative values. The objective scatter index (p  <  0.005) was significantly lower than that before surgery. The postoperative VF-14 scale score was 83.99 ± 14.58.

Conclusion

Toric IOL implantation has a good corrective effect on certain specific types of corneal irregular astigmatism with cataract. This effect can be attributed to its ability to correct the regular component of irregular astigmatism. The indications for toric IOL implantation could be expanded to some extent, thereby bringing benefit to more patients.

How much astigmatism to treat in cataract surgery

PURPOSE OF REVIEW

Astigmatism correction in cataract surgery is a common surgical challenge. Although there are numerous approaches to its treatment during cataract surgery, there remains a lack of consensus on what level of postoperative astigmatism to target. We examine the literature to determine the effect of astigmatism on visual function and provide a recommendation on how much to treat in cataract surgery.

RECENT FINDINGS

Distance visual acuity decreases as myopic, hyperopic, or mixed astigmatism increases. Near visual acuity decreases with hyperopic astigmatism but improves with myopic astigmatism. The effect of astigmatism is generally independent of axis; however, against-the-rule (ATR) astigmatism with mild myopia may benefit reading. A progressive ATR shift occurs with age whether or not an individual undergoes cataract surgery. In the presence of higher order aberrations, correction of astigmatism below 0.5 D shows minimal practical benefit. Presbyopia-correcting intraocular lenses (IOLs) are sensitive to astigmatism but achieve distance visual acuities similar to monofocal IOLs and reach their full near and/or intermediate potential when residual astigmatism 0.5 D or less.

SUMMARY

In cataract surgery, we recommend correction to 0.5 D or less of postoperative residual astigmatism to achieve optimum visual function and patient satisfaction following cataract surgery.