Aspheric microincision intraocular lens implantation with biaxial microincision cataract surgery: efficacy and reliability

Visual and refractive outcomes of new intraocular lens implantation after cataract surgery

To report the visual and refractive outcomes of new aspheric hydrophobic acrylic monofocal intraocular lens (IOL). Retrospective case series. This study included eyes of patients who underwent routine cataract surgery for uncomplicated age-related cataract with implantation of a Aktis SP (NS-60YG; Nidek Co. Ltd., Japan) IOL and attended regular follow ups at 1 week, 1 month, 3 months, and 12 months. At each post-operative visit, ophthalmological evaluation included measurement Uncorrected (UCVA) and Best corrected visual acuity (BCVA), contrast sensitivity, posterior capsular opacification (PCO), optical aberrations, analysis of point spread function (PSF) and modulation transfer function (MTF). The study included 2102 eyes of 1358 patients aged 45 to 75 years (mean age 62.6 years ± 5.6 SD). The mean preoperative BCVA was 0.56 ± 0.26 logMAR. At 1 year follow up, the mean postoperative UCVA and BCVA were 0.11 ± 0.09 and 0.02 ± 0.03 logMAR, respectively. At the end of 6 months, around 1487 (93%) eyes had BCVA of 20/20 and better than 20/30 in 100% of the eyes. Mild posterior capsule opacification (PCO) was observed in 56 patients, but none required Nd YAG laser capsulotomy. There was reduction in ocular spherical aberration and Higher order aberrations (HOAs) as compared to pre operative. This explains better contrast sensitivity obtained by MTF and PSF values. The study shows that the Aktis SP IOL is safe, effective, and stable lens that could be inserted through 2.2 mm incision with satisfactory visual and refractive outcomes, even in late post-operative period.

Effect of capsular tension ring implantation on capsular stability after phacoemulsification in patients with weak zonules: a randomized controlled trial. CTR implantation in cataract patients with weak zonules

BACKGROUND

The use of capsular tension ring (CTR) implantation to treat cataract patients with weak zonules is still controversial. The aim of this study was to examine the effects of CTR implantation on capsular stability after phacoemulsification in patients with weak zonules, especially patients who have undergone pars plana vitrectomy (PPV) or those who suffer from severe myopia.

METHODS

A total of 42 patients who underwent phacoemulsification and received an intraocular lens (IOL) were randomized to undergo CTR implantation or not. The control and CTR groups were compared in terms of uncorrected distant visual acuity (UDVA), best corrected distant visual acuity (BCDVA), refractive prediction error, the area of anterior capsulorhexis, and IOL inclination angle. Follow-up visits were conducted postoperatively at 1 day, 1 week, 1 month and 3 months. Subgroup analyses were performed based on PPV and severe myopia.

RESULTS

Surgery significantly improved UDVA and BCDVA to similar extents in CTR and control patients, and refraction prediction error was similar between the two groups at all follow-up times. At 3 months after surgery, the area of anterior capsulorhexis was significantly larger in CTR patients than in controls (p = 0.0199). These differences were also significant between the subgroups of patients with severe myopia. Vertical IOL inclination was less within CTR groups at 3 months after surgery, especially in patients with severe myopia (p = 0.0286). At 1 week postoperatively, the proportion of individuals whose posterior lens capsule that had completely adhered to the posterior IOL surface was significantly higher among CTR patients (p = 0.023). No serious surgical complications were observed.

CONCLUSION

CTR implantation can benefit cataract patients with weak zonules by maintaining the shape of the capsular bag, reducing capsule shrinkage and stabilizing IOL inclination.

TRIAL REGISTRATION

Chinese Clinical Trial Registry ChiCTR-INR-17011217 , date of registration April 22, 2017, prospectively registered.

Secondary Angle-Closure Glaucoma Due to Posterior Synechiae of Iris Following Combined Phacoemulsification and 23-Gauge Transconjunctival Vitrectomy

PURPOSE

To describe the clinical characteristics of eyes with secondary angle-closure glaucoma following combined phacovitrectomy.

METHODS

Retrospective case series.

RESULTS

Nine eyes developed angle-closure glaucoma due to iris posterior synechiae with an incidence rate of 1.82% (95% CI: 0.64 - 3%) among 493 eyes following phacovitrectomy. PDR with TRD was the most common surgical indication. Single piece IOL insertion and silicone oil were present in all cases. Fibrin in the anterior chamber was found in six eyes postoperatively. Mean degree of iris bombe was 310±79.37° at 3.55±1.87 weeks with a mean IOP of 32.56±5.89 mm of Hg. Systemic diabetes and grade of cataract were the only significant risk factors (r² =1; p= 0.016 and 0.049, respectively). Nd:YAG laser PI relieved the angle-closure attack in all cases.

CONCLUSION

Systemic diabetes and advanced grade of cataract are significant risk factors for secondary angle-closure glaucoma following combined phacovitrectomy.

A comparable study of clinical and optical outcomes after 1.8, 2.0 mm microcoaxial and 3.0 mm coaxial cataract surgery

AIM

To evaluate the clinical and optical outcomes after clear corneal incision cataract surgery (CICS) with three different incision sizes (1.8, 2.0 and 3.0 mm).

METHODS

Eyes of 150 patients with age-related cataract scheduled for coaxial cataract surgery were randomized to three groups: 1.8, 2.0, or 3.0 mm CICS. Intraoperative data and postoperative outcomes including surgically induced astigmatism (SIA), the corneal incision thickness, wavefront aberrations and modulation transfer function (MTF) of cornea were obtained.

RESULTS

There were no significant differences among the three groups in demographic characteristics and intraoperative outcome. The 1.8 and 2.0 mm microincisions showed more satisfactory clinical outcomes than the 3.0 mm incision. The 1.8 mm incision showed significantly less SIA than the 2.0 mm incision until postoperative 1mo (P<0.05), but the difference was only 0.14-0.18 D. Combined with less increased incision thickness only at postoperative 1d (P=0.013), the 1.8 mm incision presented better uncorrected distance visual acuity (UCDVA) than the 2.0 mm incision only at 1d postoperatively (P=0.008). For higher-order aberrations and other Zernike coefficients, there were no significant differences between the 1.8 mm group and 2.0 mm group (P>0.05).

CONCLUSION

Converting from 3.0 mm CICS to 1.8 or 2.0 mm CICS result in better clinical and optical outcomes. However, when incision is 1.8 mm, the benefits from further reduction in size compared with 2.0 mm are limited. The necessity to reduce the incision size is to be deliberated.

Early clinical outcome with a new monofocal microincision intraocular lens

The purpose of this study was to evaluate the early visual and refractive outcomes of a new aspheric monofocal microincision intraocular lens (IOL). This retrospective case series included eyes of patients who underwent implantation of a microincision IOL following 1.8 mm manual coaxial microincision cataract surgery and who attended regular postoperative follow-up visits on the first week and first, third, and sixth months. The postoperative uncorrected visual acuity (UCVA), best corrected visual acuity (BCVA), refraction and predictability, intraoperative and postoperative complications, posterior capsule opacification (PCO), IOL centration, and surgically induced astigmatism (SIA) were evaluated. Sixty-three eyes of 38 patients ranging in age from 51 to 86 were included in the study. The mean preoperative BCVA was 0.52 ± 0.42 logMAR. At the postoperative sixth month, the mean postoperative UCVA and BCVA were 0.12 ± 0.11 and 0.01 ± 0.03 logMAR, respectively. The mean postoperative spherical equivalent refraction (SER) was -0.30 ± 0.49 D. The SER was within ± 1.00 D of the attempted correction in 95.2 % of the eyes. The mean SIA measured with vector analysis was 0.45 ± 0.28 D. Mild PCO was observed in 9 eyes (14.7 %) with none requiring Nd:Yag laser capsulotomy. On centration analysis, the IOL was found to be 0.26 mm on average to the supero-nasal position. The aspheric microincision IOL was safely implanted and provided satisfactory visual and refractive outcomes in the early postoperative period.

Comparison of pseudophakic retinal straylight in spherical/aspherical and hydrophobic/hydrophilic intraocular lens

AIM

To study the potential reasons of increased straylight in pseudophakic eyes.

METHODS

Cross-sectional study. Seventy patients diagnosed as bilateral age-related cataract and implanted with Tecnis ZA9003, Sensar AR40e, SA60AT, XLSTABI ZO or Akeros AO intraocular lens (IOL) were enrolled in this research. Straylight was measured by a C-Quant straylight meter three to four weeks postoperatively. Five different modalities of IOL, including spherical/aspherical optics and hydrophobic/hydrophilic material were tested in this study. Normal as well as dilated pupils were used. The main outcome variable for straylight measurement was the logarithmic straylight parameter, log(s).

RESULTS

The straylight parameter increased significantly after pupil dilation (P<0.05). Straylight of aspherical IOL was significantly higher after pupil dilation (P<0.05) compared to spherical IOL. In normal pupil, straylight of hydrophobic IOL was significant higher when compared with hydrophilic IOL (P<0.05).

CONCLUSION

Straylight and visual acuity stand for the different aspects of visual function. Several factors including pupil diameter, optic material, aspherical design of IOL influence intraocular light scattering in pseudophakic eyes. Further investigation was needed to study the impact of optic material and optic surface design on pseudophakic straylight.

Risk factors for posterior synechiae of the iris after 23-gauge phacovitrectomy

AIM

To identify risk factors for the development of posterior synechiae of the iris (PSI) after 23-gauge phacovitrectomy.

METHODS

A retrospective chart review was performed in consecutive Asian patients treated with 23-gauge phacovitrectomy with a 3-piece intraocular lens (IOL) or a single-piece 4 haptics IOL.

RESULTS

A total of 263 eyes from 242 patients were included in the study. Postoperative PSI was identified in 16 (6.1%) eyes. In multivariate analysis, C3F8 gas tamponade, oil tamponade, and long operation time were significantly associated with PSI formation. There was no difference in the incidence of PSI between the groups using two different types of IOL (P=0.779).

CONLUSION

C3F8 gas or oil tamponade and long operation time increased the incidence of PSI after 23-gauge phacovitrectomy. The single-piece 4 haptics IOL, in lieu of a 3-piece IOL, may be inserted into the capsular bag with a comparable incidence of PSI.

Comparative outcomes of bimanual MICS and 2.2-mm coaxial phacoemulsification assisted by femtosecond technology

PURPOSE

To compare the efficacy and safety outcomes of bimanual microincision cataract surgery (MICS) versus 2.2-mm coaxial phacoemulsification assisted by Femtosecond LenSx (Alcon-LenSx Inc., Aliso Viejo, CA).

METHODS

This prospective, randomized, observational, comparative case series comprised 50 cataractous eyes of 50 patients receiving femtosecond laser refractive lens surgery followed by a bimanual MICS technique with two 1-mm incisions (25 patients) (FemtoMICS group) and a coaxial phacoemulsification technique with a 1-mm paracentesis and a 2.2-mm principal incision (25 patients) (FemtoCoaxial group). The main outcomes measures were: ultrasound power, effective phacoemulsification time, postoperative spherical equivalent, higher-order aberrations (corneal and internal), corneal thickness, endothelial cell count, macular thickness, and complications during and after surgery. Both groups were absolutely comparable for all variables preoperatively.

RESULTS

Mean ultrasound power was 1.8% ± 0.9% for MICS and 14.7% ± 4.9% for 2.2-mm incisions (P < .001). Effective phacoemulsification time values for MICS and 2.2-mm incisions were 1.5 ± 0.9 and 4.5 ± 2.9 sec, respectively (P = .002). Mean postoperative spherical equivalent was −0.26 for FemtoMICS and −0.33 for FemtoCoaxial (P > .05). The efficacy index at 1 month postoperatively was 160.2% for FemtoMICS and 149% for FemtoCoaxial. No significant differences were found in corneal thickness, endothelial cell count, and macular thickness. Complications included posterior capsule rupture (4%) and anterior capsule rupture with no posterior capsule tear (4%) for FemtoMICS and bridges due to incomplete capsulorhexis (4%) for FemtoCoaxial.

CONCLUSIONS

MICS and coaxial phacoemulsification techniques assisted by the Femtosecond LenSx achieved excellent safety and efficient outcomes. The FemtoMICS technique was surgically and statistically more efficient than the FemtoCoaxial technique.

Fellow-eye comparison of posterior capsule opacification between 2 aspheric microincision intraocular lenses

PURPOSE

To compare posterior capsule opacification (PCO) between 2 microincision hydrophilic intraocular lenses (IOLs) and with a conventional spherical hydrophobic IOL.

SETTING

St. Thomas' Hospital, London, United Kingdom.

DESIGN

Prospective randomized comparative study.

METHODS

A microincision Acri.Smart 36A (negatively aspheric) or Akreos MI-60 (aspherically neutral) IOL was randomized to the first eye of patients with the alternative IOL implanted in the fellow eye within 3 weeks. Postoperatively, 100% and 9% logMAR corrected distance visual acuity (CDVA) were assessed. Retroillumination photographs were analyzed using the posterior capsule opacity software system. The data on PCO scores were compared with those of a conventional spherical hydrophobic IOL (Acrysof SN60AT).

RESULTS

One hundred percent CDVA was significantly better at 12 months and 9% CDVA was better at 6, 12, and 24 months (P<.05) with the negatively aspheric IOL. One eye in each group with microincision IOLs developed capsule phimosis at 1 month. Neodymium:YAG capsulotomies were required by 2 years in 2 eyes with a negatively aspheric IOL and 8 eyes with an aspherically neutral IOL. At 24 months, the mean PCO score remained less than 10% with the conventional spherical IOL, whereas it increased with time in the negatively aspheric IOL (up to 16%) and the aspherically neutral IOL (up to 23%).

CONCLUSIONS

The negatively aspheric IOL had a better PCO profile than the aspherically neutral IOL. This may be attributed to the difference in the edge design between the IOLs. The microincision IOLs had more PCO than the conventional 1-piece hydrophobic IOL.

Fellow-eye comparison of 2 aspheric microincision intraocular lenses and effect of asphericity on visual performance

PURPOSE

To evaluate visual performance and aberrations with aspheric and spherically neutral microincision intraocular lenses (IOLs) and assess the influence of asphericity on visual performance, wavefront aberration, and depth of focus.

SETTING

St. Thomas' Hospital, London, United Kingdom.

DESIGN

Clinical trial and cohort study.

METHODS

In the first study, patients with bilateral cataract were randomized to receive an aspheric Acri.Smart 36A IOL or a spherically neutral Akreos MI60 IOL in the first eye. The other IOL was implanted in the second eye within 3 weeks. Assessments at 3 months were 100% and 9% corrected distance visual acuity (CDVA) and distance-corrected near visual acuity (DCNVA). Aberrations and depth of focus were computed using iTrace software. In the second study, data from the other published study was combined to assess the visual performance, aberration, and depth of focus in groups of spherical, spherically neutral, and negatively aspheric (asphericity -0.17 μm) IOLs.

RESULTS

In part 1, there was no difference in 100% or 9% CDVA, DCNVA, or depth of focus between the 2 microincision IOLs. Total spherical aberration was lower with the aspheric IOL. In part 2, the CDVA and DCNVA were not different between the spherical (n = 44), spherically neutral (n = 32), or aspheric (n = 76) IOLs. Total spherical (P<.01) and vertical coma aberrations decreased with increasing IOL asphericity (P<.01). Depth of focus (4.0 mm pupil) also decreased with increasing asphericity and was significant between the spherical IOL and aspheric IOLs. The DCNVA did not differ between groups.

CONCLUSION

Asphericity of IOLs did not affect distance visual acuity. The difference in depth of focus was significant only between negatively aspheric and spherical IOLs. Asphericity differences up to 20 μm did not influence depth of focus.

Wavefront analysis and Zernike polynomial decomposition for evaluation of corneal optical quality

Wavefront-guided excimer laser refractive surgery and new customized intraocular lens and contact lens designs are major clinical applications of corneal wavefront analysis. Other therapeutic applications include corneal disorders, conventional excimer laser refractive surgery, incisional techniques and cataract surgery, corneal transplantation, intrastromal corneal ring segment implantation, and crosslinking therapy. Basic data regarding corneal wavefront aberrations, such as distribution in the population and changes with aging, are essential for understanding the nature of each aberration and correcting it. Corneal aberrometry also improved our comprehension of the optical effects of the aforementioned topics while helping us assess the success of the procedures. Zernike polynomials are representations of the higher- and lower-order aberrations of the cornea, allowing a mathematical approach to their determination. Polynomials are used to model individual components of the wavefront in familiar terms. This article reviews the current knowledge of the wavefront aberrations of the human cornea and analyzes studies in the fields of anterior segment surgery and/or therapy, diseases, and optical quality in the context of this knowledge.