Different-sized incisions for phacoemulsification in age-related cataract

Proteomics identifies hypothermia induced adiponectin protects corneal endothelial cells via AMPK mediated autophagy in phacoemulsification

AIM

To explore the molecular mechanism underlying the protective effect of hypothermic perfusion on the corneal endothelium during phacoemulsification.

METHODS

Phacoemulsification was performed on New Zealand white rabbits. Perfusate at different temperatures was used during the operation, and the aqueous humor was collected for proteomic sequencing after the operation. Corneal endothelial cell injury was simulated by a corneal endothelial cell oxygen-glucose deprivation/reoxygenation (OGD/R) model in vitro. Flow cytometry and evaluation of fluorescent LC3B puncta were used to detect apoptosis and autophagy, and western blotting was used to detect protein expression.

RESULTS

A total of 381 differentially expressed proteins were identified between the two groups. In vitro, 4 ℃ hypothermia significantly reduced apoptosis and promoted autophagy. Apoptosis increased after autophagy was inhibited by 3-Methyladenine (3-MA). Furthermore, adiponectin (ADIPOQ) knockdown inhibited phospho-AMPK and blocked the protective effect of hypothermia on corneal endothelial cells.

CONCLUSIONS

We investigated the differential expression of proteins between the hypothermia group and normothermia group by proteomics. Moreover, hypothermia-induced ADIPOQ can reduce apoptosis by promoting AMPK-mediated autophagy.

Comparison of astigmatism correction and visual outcomes in mix-and-match implantations of trifocal intraocular lenses with femtosecond laser-assisted arcuate keratotomy and contralateral bifocal Toric intraocular lenses

Introduction

Astigmatism reduces the postoperative visual performance after non-toric intraocular lenses (IOLs) implantation, and limits the use of refractive IOLs in cataract surgery. The purpose of this study was to compare the efficacy in astigmatism correction and the postoperative visual outcomes between the implantation of a trifocal IOL with femtosecond laser-assisted arcuate keratotomy (FSAK) in one eye and a bifocal toric IOL (TIOL) in the other, in patients with cataract and moderate astigmatism.

Methods

This prospective observational paired-eye study enrolled patients with cataract and corneal astigmatism (CA) between 0.75 and 2.25 D in both eyes. The patients underwent a mix-and-match treatment comprising trifocal IOL implantation with FSAK and bifocal TIOL implantation. We compared the visual acuity (VA) at all distances, defocus curve, postoperative refractive astigmatism (RfA), CA, high-order aberrations, modulation transfer function (MTF) curve, and Strehl ratio between the two eye groups.

Results

In total, 41 patients (82 eyes) were enrolled and completed a 6-month follow-up. The 1- and 3-month uncorrected distance VA and 3-month uncorrected near VA were greater in eyes with bifocal TIOLs than with trifocal IOLs and FSAK (p = 0.036, 0.010, and 0.030, respectively), whereas the latter had greater uncorrected intermediate VA at every visit and greater VA in the intermediate range of defocus curve (at -1.50 and - 2.00 D) than the eyes with bifocal TIOLs. The postoperative RA of the eyes with trifocal IOL and FSAK was significantly higher than that of the bifocal TIOL-implanted eyes at the 3- and 6-month follow-ups.

Discussion

Both FSAK and TIOL implantation effectively reduce pre-existing moderate astigmatism in patients with cataract. The eyes with bifocal TIOLs had more stable long-term astigmatism correction, whereas those with trifocal IOLs and FSAK had better intermediate VA. Therefore, a mix-and-match implantation of trifocal IOL with FSAK and contralateral bifocal TIOL could achieve effective astigmatism correction and provide an overall optimal VA.

Correlation Between Degree of Lens Opacity and the Phacoemulsification Energy Parameters Using Different Imaging Methods in Age-Related Cataract

Purpose

To compare the correlation between degree of lens opacity and the phacoemulsification energy parameter in patients with age-related cataract as determined by slit lamp, 25-MHz ultrasound biomicroscopy (UBM), and Scheimpflug imaging (Pentacam) and to evaluate the application of these three methods to measuring lens opacification.

Methods

This observational study was conducted in 319 patients (381 eyes) with different types of age-related cataract. The average age of patients was 67.3 ± 11.4 years. The degree of lens opacity acquired by slit lamp, 25-MHz UBM, and Pentacam was determined by the Lens Opacity Classification System III (LOCSIII), pixel units calculated by ImageJ, and lens density, respectively. We primarily analyzed and compared the correlation between lens opacity and the cumulative dissipated energy (CDE) values of phacoemulsification.

Results

Cortical, nuclear, and posterior subcapsular (PSC) cataracts were evaluated as follows: LOCSIII grades 3.31 ± 1.42, 3.29 ± 1.49, and 0.91 ± 0.83; pixel units 120.91 ± 22.8, 93.2 ± 15.9, and 99.7 ± 13.0; and lens density 51.8 ± 31.2, 21.2 ± 6.10, and 53.3 ± 35.3, respectively. The CDE values were 12.1 ± 12.4, 13.5 ± 9.11, and 3.93 ± 1.96. In cortical cataract, there was a linear correlation among LOCSIII, pixel units, and CDE value (r = 0.560, r = 0.832, and r = 0.582, respectively; both P < 0.05), but lens density had no correlation with other parameters. In nuclear cataract, there was a linear correlation among LOCSIII, lens density, and CDE value (r = 0.747, r = 0.865, and r = 0.906, respectively; both P < 0.05), but pixel units had no correlation with other parameters. In PSC, only pixel units and LOCSIII showed a correlation.

Conclusions

The various imaging methods offered different advantages in terms of determining lens opacity, a feature related to types of age-related cataracts. Choosing the most suitable imaging method to evaluate lens opacification based on the type of age-related cataract is important for accurately predicting the phacoemulsification parameters for cataract surgery.

Translational Relevance

Determining the appropriate phacoemulsification strategy depends on quantitative analysis of the degree of lens opacity to reduce intraoperative and postoperative complications and to obtain the optimal postoperative visual outcome.

Risk factors for fluctuations in corneal endothelial cell density (Review)

The cornea is a transparent, avascular and abundantly innervated tissue through which light rays are transmitted to the retina. The innermost layer of the cornea, also known as the endothelium, consists of a single layer of polygonal endothelial cells that serve an important role in preserving corneal transparency and hydration. The average corneal endothelial cell density (ECD) is the highest at birth (~3,000 cells/mm²), which then decrease to ~2,500 cells/mm² at adulthood. These endothelial cells have limited regenerative potential and the minimum (critical) ECD required to maintain the pumping function of the endothelium is 400-500 cells/mm². ECD < the critical value can result in decreased corneal transparency, development of corneal edema and reduced visual acuity. The condition of the corneal endothelium can be influenced by a number of factors, including systemic diseases, such as diabetes or atherosclerosis, eye diseases, such as uveitis or dry eye disease (DED) and therapeutic ophthalmological interventions. The aim of the present article is to review the impact of the most common systemic disorders (pseudoexfoliation syndrome, diabetes mellitus, cardiovascular disease), eye diseases (DED, uveitis, glaucoma, intraocular lens dislocation) and widely performed ophthalmic interventions (cataract surgery, intraocular pressure-lowering surgeries) on corneal ECD.

Cataract: Advances in surgery and whether surgery remains the only treatment in future

Background

Cataract is the world's leading eye disease that causes blindness. The prevalence of cataract aged 40 years and older is approximately 11.8%-18.8%. Currently, surgery is the only way to treat cataracts.

Main Text

From early intracapsular cataract extraction to extracapsular cataract extraction, to current phacoemulsification cataract surgery, the incision ranges from 12 to 3 ​mm, and sometimes to even 1.8 ​mm or less, and the revolution in cataract surgery is ongoing. Cataract surgery has transformed from vision recovery to refractive surgery, leading to the era of refractive cataract surgery, and premium intraocular lenses (IOLs) such as toric IOLs, multifocal IOLs, and extended depth-of-focus IOLs are being increasingly used to meet the individual needs of patients. With its advantages of providing better visual acuity and causing fewer complications, phacoemulsification is currently the mainstream cataract surgery technique worldwide. However, patient expectations for the safety and accuracy of the operation are continually increasing. Femtosecond laser-assisted cataract surgery (FLACS) has entered the public's field of vision. FLACS is a combination of new laser technology and artificial intelligence to replace fine manual clear corneal incision, capsulorhexis, and nuclear pre-fragmentation, providing new alternative technologies for patients and ophthalmologists. As FLACS matures, it is being increasingly applied in complex cases; however, some think it is not cost-effective. Although more than 26 million cataract surgeries are performed each year, there is still a gap in the prevalence of cataracts, especially in developing countries. Although cataract surgery is a nearly ideal procedure and complications are manageable, both patients and doctors dream of using drugs to cure cataracts. Is surgery really the only way to treat cataracts in the future? It has been verified by animal experiments that lanosterol therapy in rabbits and dogs could make cataract severity alleviated and lens transparency partially recovered. Although there is still much to learn about cataract reversal, this groundbreaking work provided a new strategy for the prevention and treatment of cataracts.

Conclusions

Although cataract surgery is nearly ideal, it is still insufficient, we expect the prospects for cataract drugs to be bright.

Retrospective Comparison of Intraoperative Parameters, Efficacy and Safety in Cataract Surgery Between Halogen and Light-Emitting Diode (LED) Illuminated Surgical Microscope

Purpose

The objective was to compare the operative time, ultrasound time, efficacy and safety of phacoemulsification with IOL insertion between using halogen and light-emitting diode (LED) illuminated microscope.

Patients and Methods

Two hundred and twenty-seven surgical charts of cataract patients who underwent phacoemulsification with IOL insertion between June 2018 and October 2020 were reviewed. There were 113 cases operated on under halogen-illuminated microscope (Carl Zeiss OPMI LUMERA S7^®) and 114 cases operated on under light-emitting diode (LED)-illuminated microscope (Leica PROVEO 8^®). All cases were operated on by the same surgeon (S.T.). The difference in operative time and ultrasound time between two groups was compared by independent samples t-test. The proportion of cases with 3-months BCVA that was better than 20/30 and the proportion of cases with intraoperative complications from the operation between two groups were compared by Pearson’s Chi-squared test.

Results

The mean ultrasound time was 121.29±53.60 seconds in halogen group and 123.98±61.53 seconds in LED group. The mean difference was −2.69±8.44 seconds which was not statistically significant (95% CI, −19.35 to 13.97; p=0.573). The mean operative time was 19.83±4.77 minutes in the halogen group and 17.20±3.02 minutes in the LED group. The mean difference was 2.63±0.53 minutes (95% CI, 1.59 to 3.67; p < 0.001). The cases with BCVA better than 20/30 was 93.69% in halogen group and 95.49% in LED group. The proportion of cases with intraoperative complications was 3.53% in halogen group and 2.63% in LED group. The difference of both proportions was not statistically significant (p=0.553 and p=0.692, respectively).

Conclusion

This study shows statistically significant operative time reduction with LED microscope. This evidence could be used for making the decision to switch from halogen microscope to LED microscope. Upgrading to LED-illuminated microscope might be beneficial for productivity improvement if there were at least six to seven cases operated on per day. The ultrasound time, efficacy, and safety showed no significant difference.

MicroRNA-124 facilitates lens epithelial cell apoptosis by inhibiting SPRY2 and MMP-2

Age-related cataract (ARC) is the primary cause of blindness worldwide. Abnormal expression of microRNAs (miRNAs/miRs) has been reported to be associated with multiple diseases, including ARC. However, the potential role of miR-124 in ARC remains unclear. The present study used the human lens epithelial cell line, SRA01/04, to investigate the potential role of miR-124 in ARC. Reverse transcription-quantitative PCR analysis was performed to detect the expression levels of miR-124, protein sprouty homolog 2 (SPRY2) and matrix metalloproteinase-2 (MMP-2) in ARC tissues, while western blotting was performed to detect the protein levels of SPRY2 and MMP-2. Cell viability and apoptosis of SRA01/04 cells were assessed via Cell Counting Kit-8 and TUNEL assays, respectively. The interaction between miR-124 and SPRY2 or MMP-2 was confirmed via the dual-luciferase reporter and RNA immunoprecipitation assays. The results of the present study demonstrated that miR-124 expression was significantly upregulated in ARC tissues, and knockdown of miR-124 increased SRA01/04 cell viability and suppressed apoptosis. In addition, SPRY2 and MMP-2 expression was decreased in ARC tissues, and were demonstrated to directly bind to miR-124. Overexpression of SPRY2 or MMP-2 increased SRA01/04 cell viability and repressed apoptosis, the effects of which were reversed following overexpression of miR-124. Taken together, these results suggested that miR-124 facilitates lens epithelial cell apoptosis by modulating SPRY2 or MMP-2 expression, providing a novel treatment approach for ARC.

One-year follow-up of changes in refraction and aberrations induced by corneal incision

Purpose

To evaluate the surgically induced changes in refraction (sphere and astigmatism) and higher order aberrations by corneal incision for one year.

Setting

University Hospital “Virgen de la Arrixaca”, Murcia, Spain.

Design

Retrospective interventional case series.

Methods

Corneal power, astigmatism and higher order aberrations (HOA) were calculated from corneal topography measured in 27 eyes prior to surgery and at 2 weeks, 1, 2, 3 and 6 months and 1 year following cataract surgery with 3.2-mm corneal incision. At every stage, optical changes were calculated as the difference between pre- and post-surgery data (in each follow-up) using the formulas of obliquely crossed cylinders for the refraction and Zernikes coefficients for HOA.

Results

At 2 weeks after surgery the mean corneal values of induced sphere, cylinder and the root mean square (RMS) of HOA were +0.54±0.27 D, -0.77±0.32 D and 0.15 microns respectively. These parameters decreased significantly (p-values between 0 and 0.01) at 3 months to +0.33±0.27 D sphere, -0.50±0.24 D cylinder and 0.10±0.05 microns HOA and were stable at the next follow-ups. Induced spherical equivalent was around zero at all visits. The changes in HOA were mainly due to trefoil aberration.

Conclusions

Linear corneal incisions do not change the spherical power but can induce significant values of astigmatism and trefoil aberration in the cornea. However, these changes revert fully or partially to preoperative values by the third month after surgery and remain stable with time.

Astigmatismus

Der Astigmatismus ist der weltweit häufigste Refraktionsfehler vor Hypermetropie und Myopie. Man unterscheidet den äußeren vom inneren Astigmatismus. Der äußere Astigmatismus kann weiter in „mit der Regel“, „gegen die Regel“ und „schräg“ unterteilt werden. Die Summierung des äußeren und inneren Astigmatismus ergibt den refraktiven Zylinder. Astigmatismus wurde lange als zweidimensionales Phänomen gesehen, doch erst die dreidimensionale Betrachtung hat den Blick auf bestehende Analyseverfahren (Topo- und Tomographie) erweitert. Die Vektoranalyse nach Alpins ist hierbei eine bekannte Methode zur Therapieplanung. Zur Therapie des Astigmatismus stehen konservative Optionen wie Brille oder torische Kontaktlinse sowie unterschiedlichste chirurgische Verfahren wie photorefraktive Keratektomie, Femtosekundenlaser-assistierte Keratotomie, Laser-in-situ-Keratomileusis, „small-incision lenticule extraction“ und die Implantation torischer Intraokularlinsen zur Verfügung.

[Astigmatism]

Astigmatism is the most frequent refractive error worldwide followed by hyperopia and myopia. Internal astigmatism has to be differentiated from external astigmatism. Furthermore, external astigmatism can be divided into "with the rule", "against the rule" and "oblique". The summation of internal and external astigmatism results in the refractive cylinder. Astigmatism has for a long time been regarded as a two-dimensional phenomenon; however, only a three-dimensional consideration expanded the view on existing analytical methods (topography and tomography). Alpins' vector analysis is a commonly used method for treatment planning. Multiple options exist for treatment of astigmatism with conservative approaches, such as eyeglasses or toric contact lenses as well as various surgical procedures, such as photorefractive keratectomy, femtosecond laser-assisted keratotomy, laser in-situ keratomileusis, small incision lenticule extraction and toric intraocular lens implantation.

Induction of oxidative stress in human aqueous and vitreous humors by Nd:YAG laser posterior capsulotomy

AIM

To evaluate whether the Q-switched Nd:YAG laser treatment applied in routine capsulotomy elicits oxidative stress in aqueous and vitreous humors.

METHODS

Thirty-six patients who had to undergo a 25 gauge pars plana vitrectomy due to vitreoretinal disorders were enrolled, 15 of them underwent a Q-switched Nd:YAG laser capsulotomy 7d before vitrectomy due to posterior capsule opacification (PCO) (Nd:YAG laser group) while the remaining 21 patients were not laser treated before vitrectomy (no Nd:YAG laser group). Samples of the aqueous and vitreous humors were collected during vitrectomy from all patients for the assessment of oxidative parameters which were compared between the Nd:YAG laser group and no Nd:YAG laser group. Thiobarbituric acid reactive substances (TBARS), a product of membrane lipid peroxidation, nitrite levels, the antioxidative activities of SOD and catalase, the 4-HNE-protein conjugate formation, indicating structural modifications in proteins due to lipoperoxidation, were assessed in aqueous and vitreous samples.

RESULTS

In the human vitreous humor TBARS levels are significantly higher in the Nd:YAG laser group compared to the no Nd:YAG laser group and importantly, there is a significant correlation between the TBARS levels and the total energy of Nd:YAG laser used during capsulotomy. Moreover the anti-oxidative activities of SOD and catalase were significantly decreased by Nd:YAG laser treatment, both in aqueous and vitreous humors. In accordance with the TBARS data and anti-oxidative enzyme activities, significantly higher levels of proteins were conjugated with the lipoperoxidation product 4-HNE in the aqueous and vitreous humors in the Nd:YAG laser-treated group in comparison to no Nd:YAG laser group.

CONCLUSION

These data, clearly suggest that any change that Q-switched Nd:YAG photo disruption may cause in the aqueous and vitreous compartments, resulting in a higher level of oxidative damage might be of considerable clinical significance particularly by accelerating the aging of the anterior and posterior segments of the eye and by worsening the intraocular pressure, the uveal, the retinal (especially macular) pathologies.

Corneal astigmatism in cataract surgery patients from Bosnia and Herzegovina

PURPOSE

To determine corneal astigmatism prevalence, its correlations with age and symmetry pattern in fellow eyes of patients undergoing cataract surgery.

METHODS

This is a clinical-based retrospective cross-sectional study. Keratometry measurements of patients undergoing cataract surgery assigned to University Clinical Center Tuzla, Bosnia and Herzegovina, between January 2011 and June 2012 were recorded and analyzed retrospectively.

RESULTS

The study consisted of 4080 eyes of 2205 consecutive cataract surgery patients with a mean age of 68.24 years ± 9.25 (SD) (range 32-84 years), and 54.0% of the patients were women. Mean corneal astigmatism was 0.72 ± 0.61 D (range 0-6.5 D). The prevalence of corneal astigmatism 1.0 D or more was in 1291 eyes (31.64%), 1.5 D or more in 736 eyes (18.03%), 2.0 D or more in 396 eyes (9.71%) and 3.0 D or more in 108 eyes (2.65%). There was no significant difference in the magnitude of astigmatism between age groups (p = 0.10), male and female (p = 0.29) or right and left (p = 0.75) eyes. The prevalence and amount of astigmatism increased with age (p < 0.05). Gradual shift from with-the-rule astigmatism toward against-the-rule astigmatism was observed (p = 0.03). Patients with higher amount of astigmatism in one eye are more likely to have significant astigmatism in fellow eye (p < 0.01). Symmetry in pairs of eyes is present in eyes with astigmatism greater than 2.5 D (p < 0.01).

CONCLUSION

This study provides useful reference data for cataract surgeons and patients from Bosnia and Herzegovina.

A comparison of surgical efficacy between a 1.8-mm microincision and 3.2-mm and 5.5-mm incisions for phacoemulsification

Phacoemulsification is a commonly used surgical method in cataract surgery. This paper observes and compares the surgical efficacy of three incisions of different length for phacoemulsification to identify the optimal method for cataract surgery. Ninety patients were enrolled in the present study and divided into three groups. The 1.8-mm group received Bausch & Lomb MI60 foldable intraocular lens (IOL) implantation (n=30), 3.2-mm group received Bausch & Lomb Akreos AO foldable lens implantation (n=30), and 5.5-mm group received Alcon TYPE 05 rigid IOL implantation (n=30). Visual acuity, Oculyzer-based anterior segment analysis, and corneal endothelial cell count before surgery, and 3, 7, 30, and 90d after surgery were recorded and compared. Pseudophakic accommodation three days, one week, one month, and three months after surgery was determined. Intraoperative ultrasound time and ultrasonic energy were recorded. It was finally concluded that for phacoemulsification with the same phaco tip, a 1.8-mm microincision can lead to quicker recovery of visual acuity, more stable astigmatism, and higher pseudophakic accommodation than conventional incision.