The use of toric intraocular lens to correct astigmatism at the time of cataract surgery

Bibliometric analysis of research relating to refractive cataract surgery over a 20-year period: from 2003 to 2022

AIM

To investigate the research trend on refractive cataract surgery, compare the contributions of different countries, institutions, journals, and authors in the past 20y, and explore its potential research hotspots.

METHODS

All publications were extracted relating to refractive cataract surgery from 2003 to 2022 from Web of Science. Document types were limited to original articles and reviews, and the language was limited to English. Quantitatively and qualitatively of the publications were analyzed through Microsoft Excel and GraphPad Prism. VOSviewer and CiteSpace were used for bibliometric and visualized analysis.

RESULTS

A total of 2090 publications were enrolled. The United States contributed the most publications (434, 20.8%), followed by China (345, 16.5%) and England (163, 7.80%). Publications from the United States were cited more frequently (9552 citations) with the highest H-index of 48. China ranked second in the total number of publications, the papers were not cited that frequently (3237 citations), and the H-index ranked sixth (H-index=29). Journal of Cataract and Refractive Surgery published the most papers (333, 15.9%), and the University of London had the highest number of publications (75, 3.59%). Dick HB from Germany published the most papers. Corneal astigmatism-related research, cataract surgery method-related research, postoperative visual-quality relate to research, and postoperative complications-relate research are the hotspots in this field. The most significant limitation was that the database was updated frequently and the latest publications were not included.

CONCLUSION

The bibliometric analysis shows a brief summarization of the contribution of the authors, institutions, countries, and journals. Corneal astigmatism, cataract surgery method, postoperative visual-quality and postoperative complications related researches have become the emerging hotspots, which can give a direction in the future researches.

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

Purpose

To evaluate near, intermediate, distance visual acuity and stereopsis after bilateral implantation of Toric intraocular lenses (IOLs) in high myopic patients with astigmatism.

Methods

Bilateral 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.

Results

The 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).

Conclusions

In bilateral high myopic cataract patients with astigmatism, Toric IOLs not only improved UCIVA, UCNVA, and RRA, but also enhanced near and intermediate stereopsis acuity.

Visual outcome and refractive status with monofocal toric intraocular lens implantation to correct astigmatism during cataract surgery

Purpose:

Measurement, calculations, visual assessment, and refractive status after monofocal toric intraocular lens (IOL) implantation were the purpose of this study.

Methods:

This was a hospital-based interventional prospective study, where 40 eyes were included with astigmatism of more than 2D. They underwent biometric assessment using Lenstar. Toric IOL power calculation was done based on Barrett's Toric calculation method. Preoperative axis marking was done using both bubble marker and direct slit beam to avoid cyclotorsion in sleeping position. On table, axis marking was reassessed. Post phacoemulsification, monofocal Supra Phob Toric IOL was rotated till its marking matches corneal axis marking. Postoperative best-corrected visual acuity was measured at 1 and 3 months.

Results:

Mean of refractive astigmatism reduced from 3.55 ± 0.97 preoperatively to 0.81 ± 0.28 at 1 month and 0.79 ± 0.27 at 3 months postoperatively. In total, 92.5% had residual astigmatism less than 1D at 3 months postoperatively, while 7.5% eyes had residual astigmatism more than 1D. In total, 72.5% patients had IOL rotation of less than or equal to 5°, 20% patients had it between 6° and 10° and 7.5% eyes had more than 10° at day 7 postoperatively, which required IOL repositioning.

Conclusion:

Accurate measurement of parameters and proper calculation reduce the postoperative residual astigmatism after toric IOL.

Early-stage clinical outcomes and rotational stability of TECNIS toric intraocular lens implantation in cataract cases with long axial length

Background

A major focus of toric intraocular lens (IOL) implantation is the rotational stability, especially in the patients with long axial length (AL). In this study, we aimed to evaluate the clinical outcomes after implantation of TECNIS toric IOL in eyes with long AL and identify factors influencing their early-stage stability with preoperative corneal astigmatism.

Methods

The study population consisted of 64 eyes from 52 cataract patients, and these patients had preoperative corneal astigmatism between 1.0 and 3.7 diopters (D) and underwent phacoemulsification and TECNIS toric IOL implantation. Ophthalmic biological measurements were carried out preoperatively, including AL, anterior chamber depth (ACD), lens thickness (LT), vitreous length (VL), anterior chamber volume (ACV), sulcus-to-sulcus (STS) and keratometric value (K). Clinical examinations, including visual acuity, manifest refraction, keratometry, digital anterior segment photographs with pupillary dilation, were performed at 1 and 3 months after surgery.

Results

The mean best corrected distance visual acuity (BCDVA) was improved from 0.93 ± 0.35 logarithms of the minimal angle of resolution (logMAR) preoperatively to 0.07 ± 0.10 logMAR postoperatively at 3 months after surgery. The mean residual astigmatism (RAS) was 0.91 ± 0.74D at 3 months, which was significantly decreased compared with the preoperative corneal astigmatism of 1.71 ± 0.55 D. The mean absolute rotation of TECNIS toric IOL at 1 and 3 months was 7.42 ± 11.32 degree (°) (0–79°) and 7.48 ± 11.19°(0–79°), respectively. The mean area of capsulorhexis and the overlapped area between capsulorhexis and IOL optic intraoperatively was 21.04 ± 3.30 mm² and 7.40 ± 2.87 mm².A positive correlation was found between IOL rotation and the area of capsulorhexis (p = 0.017) at 3 months after surgery. No correlation was found between IOL rotation and AL (p = 0.876), ACD (p = 0.387), LT (p = 0.523), VL (p = 0.546), ACV (p = 0.480), STS (p = 0.884), K1 (p = 0.429), K2 (p = 0.644), average of K1 and K2 (p = 0.520), intraoperative IOL axial direction (p = 0.396), preoperative corneal astigmatism (p = 0.269) or the overlapped area between capsulorhexis and IOL optic intraoperatively (p = 0.131) .

Conclusions

The large CCC was a risk factor for toric IOL rotation. An appropriately smaller sized CCC was conducive to increase the rotational stability of TECNIS toric IOL implantation in cataract cases with long AL.

Occlusion for stimulus deprivation amblyopia

BACKGROUND

Stimulus deprivation amblyopia (SDA) develops due to an obstruction to the passage of light secondary to a condition such as cataract. The obstruction prevents formation of a clear image on the retina. SDA can be resistant to treatment, leading to poor visual prognosis. SDA probably constitutes less than 3% of all amblyopia cases, although precise estimates of prevalence are unknown. In high-income countries, most people present under the age of one year; in low- to middle-income countries, people are likely to be older at the time of presentation. The mainstay of treatment is correction of the obstruction (e.g., removal of the cataract) and then occlusion of the better-seeing eye, but regimens vary, can be difficult to execute, and traditionally are believed to lead to disappointing results.

OBJECTIVES

To evaluate the effectiveness of occlusion therapy for SDA in an attempt to establish realistic treatment outcomes and to examine evidence of any dose-response effect and assess the effect of the duration, severity, and causative factor on the size and direction of the treatment effect.

SEARCH METHODS

We searched CENTRAL (2018, Issue 12), which contains the Cochrane Eyes and Vision Trials Register; Ovid MEDLINE; Embase.com; and five other databases. We used no date or language restrictions in the electronic searches. We last searched the databases on 12 December 2018.

SELECTION CRITERIA

We planned to include randomized controlled trials (RCTs) and controlled clinical trials of participants with unilateral SDA with visual acuity worse than 0.2 LogMAR or equivalent. We specified no restrictions for inclusion based upon age, gender, ethnicity, comorbidities, medication use, or the number of participants.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methodology.

MAIN RESULTS

We identified no trials that met the inclusion criteria specified in the protocol for this review.

AUTHORS' CONCLUSIONS

We found no evidence from RCTs or quasi-randomized trials on the effectiveness of any treatment for SDA. RCTs are needed in order to evaluate the safety and effectiveness of occlusion, duration of treatment, level of vision that can be realistically achieved, effects of age at onset and magnitude of visual defect, optimum occlusion regimen, and factors associated with satisfactory and unsatisfactory outcomes with the use of various interventions for SDA.

Intraoperative capsular marking for toric intraocular lens placement

Preoperatively, the surgeon instills two drops of 0.5% proparacaine and then marks the 0° and 180° points at the limbus using a Gentian violet marker and 26G needle edge. Intraoperatively, after phacoemulsification and irrigation and aspiration of the cortex are complete, the surgeon inspects the previously marked 0°–180° points on the limbus. In case the steeper astigmatic meridian needs to be marked, a Mendez Ring is used and the meridian is marked using a Gentian violet marker and 26G needle edge. The desired markings (2 mm in length only) on the anterior lens capsule can be made using 26G needle bent at the bevel or using micro-vitreoretinal scissors. The toric intraocular lens (IOL) is then rotated in the bag in the desired meridian (customized-toric IOL in 0°–180° meridian and noncustomized toric IOL in steeper marked meridian), viscoelastic substance is aspirated and corneal wounds are hydrated.

Correcting Corneal Astigmatism with Corneal Arcuate Incisions during Femtosecond Laser Assisted Cataract Surgery

BACKGROUND:

Astigmatic management is an important step to achieve the best visual quality after refractive cataract surgery. Nowadays, along with progress in cataract surgery, the femtosecond laser can produce the arcuate incisions high precisely that help the astigmatic correction. In Vietnam, it has not yet any study about this issue, so we perform this study.

AIM:

To assess the efficacy and safety of arcuate corneal incisions in treatment corneal astigmatism during femtosecond laser-assisted cataract surgery.

METHODS:

In this clinical interventional study, forty-five cases with cataract and corneal astigmatism (> 0.50D) were treated with corneal arcuate incisions and femtosecond-laser assisted cataract surgery in Vietnam National Institute of Ophthalmology, from January 2017 to May 2018. The uncorrected and corrected distance visual acuity, refraction spherical equivalent, corneal astigmatism were measured (using an OPD-Scan III topographer) before, 1 week and 3 months after surgery. Some features of arcuate corneal incisions (quantity, depth, length and morphology), spectacle independence at a distance and complications were recorded.

RESULTS:

The rate of postoperative spherical refraction equivalent was within ± 0.50D and ± 1.0D at 3 months (in 95.6% and 100% of the eyes respectively). Mean length of arcuate corneal incisions was 53.78o ± 17.683o (range: 20o to 85o). The average of preoperative corneal astigmatism was 1.65 ± 0.83D, decreased to 0.59 ± 0.549D in the third month after surgery. Surgical induced astigmatism was 1.05 ± 0.449D and lower than preoperative corneal astigmatism (1.65 ± 0.83D), thereby this indicated undercorrection. However, the rate of spectacle independence was 82.3%, and no complications were recorded.

CONCLUSION:

Correcting of corneal astigmatism in femtosecond laser-assisted cataract surgery combined with the formation of the arcuate incisions is a new and modern method for high safety and efficacy.

Optimizing outcomes with toric intraocular lenses

Toric intraocular lenses (IOLs) are the procedure of choice to correct corneal astigmatism of 1 D or more in cases undergoing cataract surgery. Comprehensive literature search was performed in MEDLINE using “toric intraocular lenses,” “astigmatism,” and “cataract surgery” as keywords. The outcomes after toric IOL implantation are influenced by numerous factors, right from the preoperative case selection and investigations to accurate intraoperative alignment and postoperative care. Enhanced accuracy of keratometry estimation may be achieved by taking multiple measurements and employing at least two separate devices based on different principles. The importance of posterior corneal curvature is increasingly being recognized in various studies, and newer investigative modalities that account for both the anterior and posterior corneal power are becoming the standard of care. An ideal IOL power calculation formula should take into account the surgically induced astigmatism, the posterior corneal curvature as well as the effective lens position. Conventional manual marking has given way to image-guided systems and intraoperative aberrometry, which provide a mark-less IOL alignment and also aid in planning the incisions, capsulorhexis size, and optimal IOL centration. Postoperative toric IOL misalignment is the major factor responsible for suboptimal visual outcomes after toric IOL implantation. Realignment of the toric IOL is needed in 0.65%–3.3% cases, with more than 10° of rotation from the target axis. Newer toric IOLs have enhanced rotational stability and provide precise visual outcomes with minimal higher order aberrations.

Toric Intraocular Lenses Versus Peripheral Corneal Relaxing Incisions for Astigmatism Between 0.75 and 2.5 Diopters During Cataract Surgery

PURPOSE

To compare the outcomes after toric intraocular lens (tIOL) or peripheral corneal relaxing incisions (PCRI) for keratometric astigmatism (K_A) between 0.75 and 2.5 diopters (D) during cataract surgery.

DESIGN

Prospective randomized clinical trial.

METHODS

Eighty eyes (80 participants) received either tIOL or PCRI and were assessed preoperatively, 1, 3, 6, and 12 months postoperatively.

PRIMARY OUTCOME MEASURE

Uncorrected (UCDVA) and best-corrected distance logMAR visual acuity (BCDVA) at 12 months.

SECONDARY OUTCOME MEASURES

Uncorrected near visual acuity (UCNVA), manifest refraction, K_A and mean keratometry (K_M), corneal aberrometry, tIOL rotation, and quality-of-life questionnaire.

RESULTS

Comparing tIOLs vs PCRIs, there was no significant difference in the UCDVA, BCDVA, and UCNVA. At 12 months, 61% vs 53% had UDCVA of 20/25 or better, 100% vs 76% gained ≥1 lines, and 59% vs 43% were within ±0.13 D spherical equivalent. In the PCRI group, anterior K_A decreased at 1 month and remained stable thereafter; there was a nonsignificant trend toward a flatter posterior K_A and steeper posterior K_M and the total corneal Z₂^-2 was low at 1 and 12 months. Over 12 months, there were changes in posterior corneal tilt, coma, and hexafoil in the PCRI group. The mean rotation of the tIOLs at 12 months was 1.8 ± 1.4 degrees. tIOL patients were happier and were glad to use the nonprescription sunglasses.

CONCLUSION

There was no difference in visual acuity, although more tIOL patients gained ≥1 line and were within ±0.13 D. After PCRIs, the anterior K_A decreased in the early postoperative period and remained stable thereafter and posterior corneal aberrations changed constantly over 12 months.