Architecture evaluation of the main clear corneal incisions in femtosecond laser-assisted cataract surgery by optical coherence tomography imaging

Predicting the impact of femtosecond-assisted arcuate keratotomy combined with tri-planar clear corneal incisions on astigmatism in implantable collamer lens surgery: one-year follow-up

PURPOSE

To investigate the factors associated with and impact on the femtosecond-assisted (FS-assisted) limbal relaxing incision (LRI) combined with the steep-meridian tri-planar clear corneal incision (TCCI) to reduce astigmatism in patients undergoing Implantable Collamer Lens (ICL) surgery.

METHODS

Retrospective case series. The study reviewed patients with ICL surgery combined with FS-assisted LRIs paired with steep-meridian TCCIs. Correlation analysis examined the relationship between independent variables, including preoperative characteristics (intraocular pressure, corneal thickness, axial length, et al.), TCCI, and LRI surgical parameters. The predictors of surgically induced astigmatism (SIA) were determined using individual-level analysis and accounting for inter-eye correlation with the generalized estimating equation (GEE).

RESULTS

The study enrolled 69 patients, with 114 eyes (55 right and 59 left). The mean spherical equivalent (SEQ) was - 10.29 ± 2.99D and - 9.99 ± 2.72D for the right and left eye, respectively, while the mean preoperative corneal astigmatism was - 1.54 ± 0.47D and - 1.54 ± 0.46D for the right and left eyes, respectively. After 12 months of follow-up, univariate analysis revealed significant correlations between SIA and intraocular pressure (IOP), astigmatism type, TCCI position (degree), peripheral corneal thickness (PCT), LRI arc incision diameter, post depth (%), and angle, respectively (P = 0.046, 0.016, 0.039, 0.040, 0.009, 0.000, 0.000). Multivariate analysis using GEE demonstrated that axial length (AL), astigmatism type, LRI arc diameter, and angle were independent predictors of SIA (P = 0.000, 0.005, 0.029, 0.000).

CONCLUSIONS

The type of astigmatism and axial length were independent factors that affected SIA when modifying the LRI arc diameter and angle through FS-assisted steep-meridian TCCI paired with LRI in ICL surgery.

Femtosecond laser-assisted cataract surgery: Update and perspectives

Cataract surgery is among the most frequently performed surgical procedures worldwide and has a tremendous impact on patients' quality of life. Phacoemulsification (PCS) is accepted as a standard of care; its technique has continuously evolved and already achieved good anatomical, visual, and refractive outcomes. Lasers in ophthalmology are widely used in clinical practice, femtosecond lasers (FSLs) for corneal surgery in particular. It was natural to assess the usefulness of FSL in cataract surgery as this technology was within reach. Indeed, precise and reproducible cuttings provided by FSL platforms could improve standardization of care and limit the risk associated with the human element in surgery and provide a step toward robot-assisted surgery. After docking and planning the procedure, femtosecond lasers are used to perform corneal incisions, capsulorhexis, lens fragmentation, and arcuate incisions in an automated manner. A well-constructed corneal incision is primordial as it offers safety during the procedure, self-seals afterward, and influences the refractive outcome. Capsulorhexis size, centration, and resistance to shearing influence the surgery, intraocular lens (IOL) centration and stability, and posterior capsular opacification formation. Lens fragmentation is where most of the energy is delivered into the eye, and its amount influences endothelial cell damage and potential damage to other ocular structures. The arcuate incisions offer an additional opportunity to influence postoperative astigmatism. Femtosecond laser-assisted cataract surgery (FLACS) has been a topic of research in many studies and clinical trials that attempted to assess its potential benefits and cost-effectiveness over PCS and is the subject of this mini-review.

Comparison of wound architecture in implantable collamer lens surgery: Self-sealing single-plane opposite clear corneal incision versus main surgical incision

PURPOSE

Incision architecture can play an important role in corneal astigmatism management through peripheral corneal relaxing incisions. The aim of this study was to compare the incision architecture of single-plane opposite clear corneal incisions (OCCIs) and main surgical incisions (MSIs) in patients undergoing implantable collamer lens (ICL) surgery.

METHODS

A retrospective cross-sectional tomographic analysis of MSI and OCCI architectures was performed 6 months after ICL surgery. Image acquisition was performed using spectral-domain anterior segment optical coherence tomography.

RESULTS

A total of 31 OCCIs and 24 MSIs were evaluated. The mean incision angle was 42.83 ± 5.69 degrees for MSIs and 48.26 ± 6.07 degrees for OCCIs (p < 0.01), and the mean MSI and OCCI length was 1146.70 ± 150.48 µm and 976.68 ± 140.19 µm, respectively (p < 0.01). The mean increase in epithelium depth in the wound was 37.63 ± 11.91 µm in the MSI group and 47.64 ± 15.45 µm in the OCCI group (p = 0.02). Endothelial misalignment was observed in both types of incisions. However, the misalignment with MSI was greater than with OCCI, 106.67 ± 31.84 µm versus 83.75 ± 23.39 µm (p = 0.01), respectively.

CONCLUSION

Both types of incisions, OCCI and MSI, were shown to be safe with complete wound sealing and healing 6 months postoperatively. The MSIs performed in the temporal position were more angled and longer, with greater endothelial retraction and minor epithelial thickening in the wound area compared with astigmatic incisions without manipulation.

Effect of corneal incision features on anterior and posterior corneal astigmatism and higher-order aberrations after cataract surgery

PURPOSE

To evaluate the influence of 2.2 mm clear corneal incision (CCI) features in surgically induced astigmatism (SIA) and higher-order aberrations (HOAs) after cataract surgery.

METHODS

Right eyes of 92 subjects receiving 2.2 mm incision cataract surgery were involved. A total of 38 eyes were categorized as the intact incision group, and 54 eyes were the defective incision group. Pre- and postoperative (1 month and 6 months) corneal astigmatism and HOAs on anterior and posterior corneal surfaces, corneal volume, and corneal thickness (CT) were measured using Pentacam. The CCI features including incision length (IL), incision angles, distance from incision to central cornea (Dis-En/Ex), and CT at incision site were quantified using AS-OCT.

RESULTS

The defective incision group showed shorter IL and larger incision angles [false discovery rate (FDR) - p < 0.05]. Changes in CT at incision site were more pronounced for the defective incision group (FDR - p < 0.05). Some SIA parameters were related to the certain specific CCI features, especially IL (FDR - p < 0.05). Both groups exhibited significant increased 6 mm posterior corneal tHOAs at 1 month (Bonferroni corrected - p < 0.01) and the defective incision group showed increased 6 mm posterior tHOAs at 6 months (Bonferroni corrected - p = 0.023). There were characteristic correlations between Zernike terms and CCI features including IL, CT, Dis-En/Ex, and incision angles at 1 month, especially over 6 mm zone.

CONCLUSION

The CCI deformities can affect corneal recovery and induce more HOAs at 1 month postoperatively. Such effects became minor, but could persist until 6 months. The IL combined with Angle-En/Ex was important factor influencing CCI integrity and corneal optical quality.

Descemet Membrane Detachment Due to Laser Application in Femtosecond Laser-Assisted Cataract Surgery: Incidence and Risk Factors

PURPOSE

To assess the incidence and risk factors of Descemet membrane detachment due to laser application in femtosecond laser-assisted cataract surgery (FLACS).

METHODS

In this retrospective case series, all patients who underwent FLACS with the LenSx system (Alcon Laboratories, Inc) were eligible to participate. The medical records were reviewed to collect data regarding potential risk factors related to Descemet membrane detachment, including patients' demographics, laser parameters, and ocular measurements. The eyes were separated into two groups based on the clinical diagnosis of Descemet membrane detachment as the femto-second laser was performing the corneal incisions.

RESULTS

Five hundred ten eyes (304 patients) were included. Descemet membrane detachment occurred in 20 (3.9%) eyes of 16 (5.3%) patients. Four (1.3%) patients had a detachment in both eyes. In 16 (3.1%) eyes, the Descemet membrane detachment occurred in the secondary incision site. The eyes that had a detachment had a statistically lower mean endothelial cell density (2,193.40 ± 313.37 versus 2,385.08 ± 357.80 cells/ mm²; P = .019), and a statistically higher prevalence of corneal guttata (25.0% versus 8.8%; P = .015). None of the other analyzed variables statistically differed between the groups (P > .05). The risk of having Descemet membrane detachment was statistically higher among eyes with guttata (odds ratio = 3.47; P = .015) and in those with an endothelial cell density of less than 2,000 cells/mm² (odds ratio = 3.26; P = .014).

CONCLUSIONS

The incidence of Descemet membrane detachment due to laser application in FLACS was 3.9%, with the associated risk factors being endothelial cell density of less than 2,000 cells/mm² and corneal guttata. [J Refract Surg. 2021;37(7):466-471.].

Evaluation of femtosecond laser-assisted cataract surgery after 10 years of clinical application

INTRODUCTION

Femtosecond laser-assisted cataract surgery (FLACS) has been considered a technological advance in modern cataract surgery. After years of experience, it has been observed that clinical outcomes had more complications than expected at the beginning. The aim of this study is to compare the benefits and disadvantages of the FLACS technique with conventional cataract surgery.

METHOD

The PubMed and Web of Science platforms were used to search for scientific literature.

RESULTS

The FLACS has currently improved the surgical technique in terms of the shorter ultrasound time used and the lower loss of endothelial cells. Likewise, the centration of capsulotomy and the correction of astigmatism with arcuate incisions have also been improved. As disadvantages, are the high cost of the laser, the intraoperative capsular complications, the induction of intraoperative myosis, and the learning curve of the technique.

CONCLUSIONS

The FLACS technique is considered beneficial for specific cases, such as patients with scheduled premium surgery, or with low endothelial cell count. However, it is believed that given the technological cost it is not a cost effective technique for most standard cases in our daily clinical practice.

The benefits and drawbacks of femtosecond laser-assisted cataract surgery

INTRODUCTION

Since the introduction, femtosecond laser-assisted cataract surgery was believed to revolutionize cataract surgery. However, the judgment of clinical benefit was found to be far more complex than initially might have been thought. The aim of this review was to analyze the benefits and drawbacks of femtosecond laser-assisted cataract surgery compared with traditional phacoemulsification cataract surgery.

METHODS

PubMed and the Web of Science were used to search the medical literature. The following keywords were searched in various combinations: femtosecond laser, femtosecond laser-assisted cataract surgery, phacoemulsification cataract surgery, FLACS.

RESULTS

The benefits of femtosecond laser-assisted cataract surgery include lower cumulated phacoemulsification time and endothelial cell loss, perfect centration of the capsulotomy, and opportunity to perform precise femtosecond-assisted arcuate keratotomy incisions. The major disadvantages of femtosecond laser-assisted cataract surgery are high cost of the laser and the disposables for surgery, femtosecond laser-assisted cataract surgery-specific intraoperative capsular complications, as well as the risk of intraoperative miosis and the learning curve.

CONCLUSION

Femtosecond laser-assisted cataract surgery seems to be beneficial in some groups of patients, that is, with low baseline endothelial cell count, or those planning to receive multifocal intraocular lens. Nevertheless, having considered that the advantages of femtosecond laser-assisted cataract surgery might not be clear in every routine case, it cannot be considered as cost-effective.