Comparison of surgically induced astigmatism between one-handed and two-handed cataract surgery techniques

Comparison of perioperative parameters in one-handed rotational phacoemulsification versus conventional phacoemulsification and femtosecond laser-assisted cataract surgery

AIM

To compare perioperative parameters of one-handed rotational phacoemulsification technique (one-handed phaco-roll) with each of other two techniques, "Divide et Conquer" and femtosecond laser-assisted cataract surgery (FLACS).

METHODS

In this retrospective and comparative cohort study, eyes with uncomplicated cataract (nuclear density grade 2 to 3) treated routinely with one-handed phaco-roll (n=23; Group 1) or "Divide et Conquer" (n=23; Group 2) or FLACS (n=23; Group 3) were enrolled. Intraoperative parameters including effective phaco-time (EPt), ultrasound time (USt), aspiration time, surgical time, phacoemulsification (phaco)-power, balanced salt solution (BSS) use, cumulative dissipated energy (CDE) were recorded and compared. Clinical outcomes including best corrected visual acuity (BCVA), corneal endothelial cell density (ECD), endothelial cell loss (ECL), central corneal thickness (CCT) and central macular thickness (CMT), were assessed and compared pre-operatively and at 1mo after surgery.

RESULTS

Aspiration and surgical time, and BSS used were lower in Group 1 (P<0.01) than other groups. EPt, phaco-power and CDE were lower in Group 1 (P<0.05) than Group 2 but not significantly different from Group 3. In Group 1, USt was lower (P<0.05) than Group 2 but higher (P<0.05) than Group 3. BCVA improved in all groups without significant difference between Group 1 and the other ones. No significant differences regarding all post-operative morphologic outcomes (ECD, ECL, CCT, CMT) were reported. No clinical complications occurred.

CONCLUSION

One-handed phaco-roll seems to be less time-consuming than "Divide et Conquer" and FLACS and less energy-consuming than "Divide et Conquer". Furthermore, one-handed phaco-roll seems to have an equal safety profile compared to the other two techniques.

One-Handed Rotational Phacoemulsification Technique

Introduction

We described a one-handed rotational phacoemulsification technique to decrease phaco time and power, and surgical stress on the cornea in eyes with different types of cataract.

Methods

In this technique a single sutureless corneal incision was made without any side-port incision. After hydrodissection and hydrodelamination were performed, a phaco tip was positioned in contact with the nucleus beside the capsulorhexis edge. By using a peristaltic pump, phacoemulsification was started with high levels of vacuum to keep the probe tip on the edge of the lens and to ensure the rotation of the nucleus, and with low ultrasound energy. The torsional mode used required less occlusion time and volume of fluid. The inclination of the tip was modified to 45-degree, directing it toward the lens center. So the nucleus was aspirated from the periphery toward the center by a rotational movement.

Results

The eye in the technical video had a NC4-NO4 cataract. The preoperative vision in this eye was 20/100 with no improvement with refraction. On postoperative day 1, visual acuity had improved to 20/20. We recorded low intraoperative parameters including ultrasound time (21.4 sec), phacoemulsification power (73%), balanced salt solution used (31 mL) and cumulative dissipated energy (7.27) at the conclusion of the case. After 1 month, Central Corneal Thickness changed from 504 µm to 516 µm, and Endothelial Cell Loss was 1.15%.

Conclusion

This technique uses a single clear corneal incision, high vacuum and low ultrasound power to reduce the exposition to excessive surgical maneuvers, fluid turbulence and ultrasound energy.

<p>Effect of Excisional Goniotomy with the Kahook Dual Blade (KDB) on Surgically Induced Astigmatism</p>

Purpose

To determine the effect of Kahook Dual Blade goniotomy with phacoemulsification (Phaco-KDB) compared to phacoemulsification alone (Phaco) on surgically induced astigmatism (SIA).

Design

Prospective study.

Participants

Forty eyes of 28 patients treated with Phaco-KDB and 20 eyes of 13 patients treated with Phaco between 12/27/16 and 7/23/19 with a minimum 1 month follow-up were prospectively enrolled.

Methods

Corneal astigmatism was assessed pre- and post-operatively using the simulated K (simK) values from the Pentacam Holladay report.

Main Outcome Measures

SIA was compared between Phaco-KDB and Phaco groups using mean magnitude SIA, rate of ≥0.50 D SIA, and SIA centroids.

Results

The difference in mean magnitude SIA was not statistically significant between Phaco-KDB and Phaco (mean = 0.28 D and 0.25 D, respectively, P = 0.621). The difference in the rate of ≥0.50 D SIA was not statistically significant between Phaco-KDB and Phaco (11.6% and 10.0%, respectively, P = 1.00). The SIA centroid for Phaco-KDB was 0.05 D @ 51° ± 0.40 D and 0.07 D @ 3° ± 0.32 D for Phaco.

Conclusion

Neither the mean magnitude SIA nor the rate of astigmatic change ≥0.50 D was significantly different between Phaco-KDB and Phaco groups. SIA centroids between groups showed comparable and negligible effect on corneal astigmatism. KDB combined with phacoemulsification may not significantly affect SIA compared to phacoemulsification alone based on postoperative topography and is likely an astigmatically neutral procedure.

Clinical Outcomes of Steep-Axis One-Handed Phacoemulsification under the Guidance of a Verion Image-Guided System

Purpose

To compare the efficiency and safety of steep-axis one-handed phacoemulsification with steep-axis two-handed phacoemulsification.

Patients and Methods

Patients with cataracts underwent steep-axis one-handed (steep-axis one-handed group) or steep-axis two-handed (steep-axis two-handed group) phacoemulsification with a 2.4 mm clear corneal incision (CCI) under the guidance of the Verion Image-Guided System. Intraoperative phacoparameters, such as visual acuity, surgically induced astigmatism (SIA), total corneal astigmatism (TCA), angle of error (AE), corneal volume (CV), and corneal endothelial cells, were compared.

Results

There were no significant differences in the intraoperative phacoparameters between the two groups. The visual outcomes were significantly better in the steep-axis one-handed group than in the two-handed group at 1 week postoperatively (all p < 0.05) but not at 1 month and 3 months postoperatively. TCAs were significantly decreased in both groups at 1 and 3 months postoperatively (all p < 0.05). There were no significant differences at any follow-up points in both groups (all p < 0.001). At 3 months postoperatively, the SIA was 0.95 ± 0.44 D in the steep-axis one-handed group and 1.01 ± 0.50 D in the steep-axis two-handed group; there was no significant difference between the groups. The AE was 39.45 ± 26.53° in the steep-axis one-handed group and 49.75° ± 26.23° in the steep-axis two-handed group, which were significantly different (p=0.005). Endothelial cell loss was significantly lower in the steep-axis one-handed group than that in the steep-axis two-handed group at all follow-up points (all p < 0.05).

Conclusions

Both the steep-axis one-handed and the steep-axis two-handed techniques could significantly decrease TCA. Compared with the steep-axis two-handed technique, the steep-axis one-handed technique has the advantage of decreasing the AE and reducing trauma to the cornea in soft-to-moderate nuclei.

Effects of steep-axis incision on corneal curvature in one-handed phacoemulsification

AIM

To examine the effects of one-handed phacoemulsification with steep-axis incision on corneal curvature and analyze surgically induced astigmatism (SIA) on the true net power, anterior and posterior corneal surfaces.

METHODS

Patients with cataracts underwent one-handed phacoemulsification with a 2.4-mm steep-axis of clear corneal incision (CCI) based on true net power. CCI was created under the guidance of Verion. Central corneal thickness (CCT), keratometry readings of the true net power and anterior and posterior corneal surface were obtained using Pentacam. Biometry, such as axial length, anterior chamber depth (ACD) and white-to-white (WTW) were performed using Lenstar pre- and 3mo post-operatively.

RESULTS

The study evaluated 68 eyes of 65 patients. The mean age was 65.93±9.40y; CCT was 529.21±37.40 µm; WTW was 11.59±0.35 mm. Regarding true net power, keratometric value at the flattest corneal meridian for the 3-mm central zone (Ks) was significantly decreased postoperatively (P=0.031). Keratometric value at the steepest corneal meridian for the 3-mm central zone (Kf) was increased postoperatively (P>0.05). Astigmatism of true net power was 1.21±0.56 D preoperatively and significantly decreased to 1.02±0.58 D postoperatively (P=0.021). On the anterior corneal surface, no significant difference in Ks and Kf was noted pre- versus postoperatively. Anterior corneal astigmatism was 1.08±0.51 D preoperatively and significantly decreased to 0.87±0.46 D postoperatively (P=0.002). On the posterior corneal surface, Ks and Kf were significantly increased postoperatively (all P<0.05), and posterior corneal astigmatism also increased (P=0.008). The SIA values of true net power and the anterior and posterior corneal surfaces at 3mo postoperatively were 1.26±0.63 D (range: 0.11 to 2.80 D), 1.05±0.54 D (range: 0.23 to 2.40 D), and 0.21±0.17 D (range: 0.01 to 0.07 D), respectively.

CONCLUSION

One-handed phacoemulsification with steep-axis incision can effectively decrease astigmatism of true net power and anterior corneal astigmatism. In the same surgery, the difference in personal SIA potentially originated from a difference in personal corneal thickness and diameter, both CCT and WTW distance should always be measured preoperatively when planning steep-axis phacoemulsification.

One-handed revolving technique for soft cataract extraction

This study describes a new one-handed revolving technique for soft cataract extraction. Following hydrodissection, the endonucleus is removed piecemeal while the lens is rotated using a phaco tip. A peripheral groove is created in the 6 o’clock direction and, after lens rotation through 180° using the phaco tip, another 6 o’clock groove is created. After a further 90° of lens rotation, the residual plate is readily flipped over and emulsified. The entire procedure requires only a phaco tip; it is not necessary to create a corneal side port or use any instrument.

Comparative Analysis of One-Handed and Two-Handed Coaxial Phacoemulsification with 2.4-mm Clear Corneal Incision

PURPOSE

To compare the efficiency and safety of one-handed and two-handed coaxial phacoemulsification Material and Methods: Patients with cataracts underwent one-handed (one-handed group) or two-handed coaxial phacoemulsification (two-handed group) with a 2.4-mm clear corneal incision. Intraoperative phaco parameters, total surgical time, postoperative visual acuity, surgically induced astigmatism (SIA), corneal volume (CV), central corneal thickness (CCT) and corneal endothelial cell counts/size were compared between the two groups.

RESULTS

Each group comprised 105 eyes. There were no significant differences in the intraoperative phaco parameters and total surgical time between the two groups (all p > 0.05). Visual outcomes were significantly better in the one-handed group than in the two-handed group 1 week postoperatively (all p< 0.05) but not 1 month postoperatively. There was no significant difference in SIA between the two groups 1 week (p = 0.695) or 1 month postoperatively (p = 0.772). CV, CCT and endothelial cell loss were significantly lower in the one-handed group than in the two-handed group 1 week postoperatively (CV: p = 0.004; CCT: p = 0.046; endothelial cell loss: p = 0.021), but the above differences were absent 1 month postoperatively except for endothelial cell loss (endothelial cell loss: p = 0.038).

CONCLUSIONS

Both one-handed and two-handed coaxial phacoemulsification were effective and safe surgical techniques. However, the one-handed technique had the advantages of less trauma to the cornea and better early clinical outcomes than the two-handed technique for cataract patients within nuclear opalescence (NO) 3 grade ≤ 3.

Comparison of variations in cornea after one-handed and two-handed coaxial phacoemulsification

Purpose

To compare corneal variations in patients undergoing one-handed and two-handed coaxial phacoemulsification.

Setting

Eye Institute, Affiliated Hospital of Nantong University, Nantong, China.

Design

Prospective consecutive nonrandomized comparative cohort study.

Methods

Patients with cataracts were subject to one-handed (one-handed group) or two-handed coaxial phacoemulsification (two-handed group). Intraoperative phaco parameters and postoperative outcomes, such as visual acuity, surgically induced astigmatism (SIA), corneal volume, central corneal thickness, and corneal endothelial cell counts/size were compared.

Results

No significant differences in the intraoperative phaco parameters were noted between the 2 groups. At postoperative week 1, visual outcomes were significantly improved in the one-handed compared with the two-handed group (all P<0.05). Corneal volume, central corneal thickness, and average cell size were significantly decreased in the one-handed group compared with two-handed group (all P<0.05), but the aforementioned differences were ameliorated at 1 month and 3 months postoperatively. Endothelial cell loss was significantly decreased in the one-handed group compared with the two-handed group at any follow-up point (all P<0.05). No significant differences in SIA on the anterior surface were noted between the 2 groups. SIA on the posterior surface was significantly decreased in the one-handed group compared with the two-handed group at 1 week postoperatively (P=0.043) but not at 1 month and 3 months postoperatively.

Conclusion

One-handed phacoemulsification has the advantages of less trauma to the cornea and better early visual outcomes compared with the two-handed technique.

Comparison of iris-fixated foldable lens and scleral-fixated foldable lens implantation in eyes with insufficient capsular support

AIM

To compare the outcomes of vision using two different intraocular lens (IOL) replacement techniques, iris-fixated foldable intraocular lens (IF-IOL) and scleral-fixated foldable intraocular lens (SF-IOL) in patients with insufficient capsular support.

METHODS

Total 63 eyes (62 patients) with insufficient posterior capsule support underwent replacement of IF-IOL or SF-IOL between January 2008 and August 2011. Outcome measures included changes in visual acuity, slit lamp examination, refractive indices and corneal curvatures.

RESULTS

The mean improvement of uncorrected visual acuity (UCVA) was greater in IF-IOL group compared to the SF-IOL group (0.43 D±0.19 D vs 0.35 D±0.18 D, P<0.05). Moreover, 12 (38.71%) eyes in IF-IOL group and 4 (12.50%) in SF-IOL group had a higher postoperative UCVA than preoperative best corrected visual acuity (BCVA) while 9 (29.03%) eyes in IF-IOL group and 18 (56.25%) in SF-IOL group had a lower postoperative UCVA than preoperative BCVA. The myopic mean manifest sphere and mean cylinder magnitude were lower in the IF-IOL group than that in the SF-IOL group (-0.47 D±0.58 D vs 0.50 D±0.43 D, P<0.01; 0.84 D±0.53 D vs 1.23 D±0.70 D, P<0.05). No difference of corneal astigmatism and surgically induced astigmatism was found between the two groups. In addition, fewer complications were observed in IF-IOL eyes.

CONCLUSION

IF-IOL implantation can give a significant improvement in vision with fewer complications than SF-IOL in patients with insufficient capsular support.

Cataract surgery on the previous corneal refractive surgery patient

Cataract surgery in cases with previous corneal refractive surgery may be a major challenge for the ophthalmologist. The refractive outcome of the case deserves special attention in the preoperative planning process, which should be tailored for the type of prior refractive procedure: incisional, ablative under a flap, or on the corneal surface. Avoiding refractive surprise after cataract surgery in these cases is principally dependent on the accuracy of the intraocular lens calculation, together with the selection of the appropriate biometric formula for each case. Modern techniques for cataract surgery help surgeons to move toward the goal of cataract surgery as a refractive procedure free from refractive error. We give practical guidelines for the cataract surgeon in the management of these challenging cases.

Surgical options for correction of refractive error following cataract surgery

Refractive errors are frequently found following cataract surgery and refractive lens exchange. Accurate biometric analysis, selection and calculation of the adequate intraocular lens (IOL) and modern techniques for cataract surgery all contribute to achieving the goal of cataract surgery as a refractive procedure with no refractive error. However, in spite of all these advances, residual refractive error still occasionally occurs after cataract surgery and laser in situ keratomileusis (LASIK) can be considered the most accurate method for its correction. Lens-based procedures, such as IOL exchange or piggyback lens implantation are also possible alternatives especially in cases with extreme ametropia, corneal abnormalities, or in situations where excimer laser is unavailable. In our review, we have found that piggyback IOL is safer and more accurate than IOL exchange. Our aim is to provide a review of the recent literature regarding target refraction and residual refractive error in cataract surgery.

Management of residual refractive error after cataract surgery

PURPOSE OF REVIEW

To provide a review of the recent literature on the management of residual refractive error after cataract surgery.

RECENT FINDINGS

Laser in-situ keratomileusis (LASIK) is the most accurate procedure to correct residual refractive error after cataract surgery. Lens-based procedures, such as intraocular lens (IOL) exchange or piggyback lens implantation, are also possible alternatives in cases with extreme ametropia, corneal abnormalities, or in situations where excimer laser is not available. In this review, we found that Piggyback IOL were safer and more accurate than IOL exchange.

SUMMARY

Emmetropia is our main target today in modern cataract surgery. Accurate biometric analysis, selection and calculation of the adequate IOL, and modern techniques for cataract surgery all help surgeons to move toward the goal of cataract surgery as a refractive procedure free from refractive error. However, in spite of all these inputs, residual refractive error still occasionally occurs after cataract surgery and LASIK seems to be the most accurate method for its correction.