[Show abstract][Hide abstract] ABSTRACT: Background:
The aim of this study was to evaluate the association between optic nerve head (ONH) parameters and branch retinal vein occlusion (BRVO) using spectral domain optical coherence tomography (SD-OCT).
Both eyes of 40 patients with unilateral BRVO (mean age: 67.4 ± 11.4 years, male: female - 18:22) were enrolled in this study. Control group consisted of randomly selected single healthy eyes of 40 age and gender matched volunteers (mean age: 64.7 ± 15.4 years, male: female - 16:24). ONH parameters (including optic disc area, optic cup area, neuroretinal rim area, cup volume, rim volume, cup-disc area ratio, horizontal and vertical cup-disc ratio, average retinal nerve fiber layer) were measured by SD-OCT. Axial length (AL) of the eyes was measured by non-contact optical low coherence reflectometry. The ONH parameters of eyes with BRVO were compared with those of fellow eyes using mixed model, one-way between-groups analysis of covariance was conducted to compare the ONH parameters of affected and unaffected fellow eyes in BRVO patients with those of the control eyes keeping confounding factors, including AL, age and gender under control in the statistical analysis.
None of the investigated ONH parameters of affected BRVO eyes, unaffected fellow eyes and control eyes were statistically different after controlling for AL, age and gender.
Optic disc morphology might not be a potential anatomical predisposing factor for development of BRVO.
Full-text · Article · Dec 2015 · BMC Ophthalmology
[Show abstract][Hide abstract] ABSTRACT: Femtosecond laser (FSL) cataract surgery is in its infancy but is rapidly gaining popularity due to the improved consistency and predictability for corneal incisions and anterior capsulorhexis. It enables subsequently less phacoemulsification energy and time to be employed, which has gains in terms of reduced corneal oedema. In addition, the FSL allows better circularity of the anterior capsulotomy, capsule overlap, intraocular lens (IOL) placement and centration of the IOL. These advantages have resulted in improved visual and refractive outcomes in the short term. Complication rates are low which reduce with surgeon experience. This review article focuses on the Alcon LenSx system.
[Show abstract][Hide abstract] ABSTRACT: To report the surgical treatment of 3 eyes of 2 patients with bilateral anterior lenticonus due to Alport syndrome using femtosecond laser-assisted cataract surgery (FLACS).
Two patients with Alport syndrome presented to our department due to anterior lenticonus in both eyes. We performed FLACS with posterior chamber lens implantation in both eyes of one patient and in one eye of the other patient. Anterior segment morphologic changes were visualized with a Scheimpflug camera, and anterior segment optical coherence tomography preoperatively and 3 months after surgery. Ultrastructure of the cut capsule edges was observed with scanning electron microscopy and compared to the edge of femtosecond laser capsulotomy performed on an otherwise healthy patient with cataract (control).
The intraocular lens (IOL) postoperative positioning parameters met the international requirements of aspherical and wavefront customized IOLs (tilt <10 degree, decentration <800 µm). Scanning electron microscopy revealed the same characteristics of the cut capsule edges in the Alport and in the control eyes.
Femtosecond laser cataract surgery can be a safe and successful method for optical rehabilitation of anterior lenticonus in patients with Alport syndrome.
No preview · Article · Apr 2015 · European journal of ophthalmology
[Show abstract][Hide abstract] ABSTRACT: To evaluate and compare the mechanical properties of anterior capsule opening performed with femtosecond laser capsulotomy at different energy settings in ex vivo porcine anterior lens capsule specimens.
Twenty-five fresh porcine eyes per group were included in the study. Femtosecond laser capsulotomy was performed with three different pulse energy levels: 2 µJ (low energy group), 5 µJ (intermediate energy group), and 10 µJ (high energy group). The capsule openings were stretched with universal testing equipment until they ruptured. The morphologic profile of the cut capsule edges was evaluated using scanning electron microscopy.
The high energy group had significantly lower rupture force (108 ± 14 mN) compared to the intermediate energy group (118 ± 10 mN) (P < .05) and low energy group (119 ± 11 mN) (P < .05), but the difference between the intermediate energy and low energy groups was not significant (P = .9479). The high energy group had significantly lower circumference stretching ratio (144% ± 3%) compared to the intermediate energy group (148% ± 3%) (P < .05) and low energy group (148% ± 3%) (P < .05), but the difference between the intermediate energy group and low energy group was not significant (P = .9985). Scanning electron microscopy images showed that the edge was only serrated with low and intermediate energy, but additional signs of collagen melting and denaturation were observed at high energy.
Anterior capsule openings created at a high energy level were slightly weaker and less extensible than those created at low or intermediate levels, possibly due to the increased thermal effect of photo-disruption. [J Refract Surg. 2015;31(3):153-157.].
Copyright 2015, SLACK Incorporated.
No preview · Article · Mar 2015 · Journal of refractive surgery (Thorofare, N.J.: 1995)
[Show abstract][Hide abstract] ABSTRACT: This article reports a case of bilateral simultaneous central retinal vein occlusion (CRVO) and protein S deficiency. The 27-year-old male patient presented with a sudden decrease in vision in both eyes. The patient's medical history documented the death of his father at the age of 33 years due to pulmonary embolism. Thrombophilia screening revealed protein S deficiency.
We report this case to emphasize that in any case of young onset retinal vein occlusion, protein S deficiency should be suspected.
Thrombophilia assays and taking a thorough medical history should be performed.
No preview · Article · Feb 2015 · Der Ophthalmologe
[Show abstract][Hide abstract] ABSTRACT: Purpose:
To review the published literature describing the use of the LenSx femtosecond laser technology (Alcon Laboratories, Inc., Fort Worth, TX) in cataract surgery.
The LenSx system has been used in more than 200,000 cataract surgery procedures to date. Pre-clinical evaluations have shown that this system produces accurate and reproducible capsulorhexes, and that both the energy required for phacoemulsification and total phacoemulsification time are less than with conventional phacoemulsification. In comparative studies, femtosecond lasers have been shown to produce more precise and reproducible capsulorhexes than manual procedures, and better intraocular lens placement; capsule overlap, circularity of capsulotomy, and centration of the intraocular lens are consistently better with femtosecond lasers than with manual procedures. The improved quality of capsulorhexis and intraocular lens positioning are reflected in favorable visual and refractive outcomes. As with any new technology, there is a significant learning curve: prospective cohort studies have shown that the incidence of intraoperative complications such as suction breaks or anterior capsular tears or tags decreases with experience. In general, the incidence of such complications is within the range (< 2%) considered in recent evidence-based guidelines to be feasible and desirable.
Although femtosecond laser cataract surgery is in its infancy, the technology is evolving rapidly and offers the potential for more consistent and predictable results after cataract surgery.
No preview · Article · Nov 2014 · Journal of refractive surgery (Thorofare, N.J.: 1995)
[Show abstract][Hide abstract] ABSTRACT: Purpose
To assess the correlation between keratoconus severity and intereye asymmetry of pachymetric data and posterior elevation values and to evaluate their combined accuracy in discriminating normal corneas from those with keratoconus.
This study included 97 patients: 65 subjects with bilateral normal corneas (NC) and 32 with keratoconus (KC). Central corneal thickness (CCT), thinnest corneal thickness (ThCT) and posterior elevation (PE) at the thinnest point of the cornea were measured in both eyes using Scheimpflug imaging. Intereye asymmetry and its correlation with keratoconus severity were calculated for each variable. The area under the receiver operating characteristic curve (AUROC) was used to compare predictive accuracy of different variables for keratoconus.
In normal eyes, intereye differences were significantly lower compared with the keratoconus eyes (p<0.001, for CCT, ThCT and PE). There was a significant exponential correlation between disease severity and intereye asymmetry of steep keratometry (r2 = 0.55, p<0.001), CCT (r2 = 0.39, p<0.001), ThCT (r2 = 0.48, p<0.001) and PE (r2 = 0.64, p<0.001). After adjustment for keratoconus severity, asymmetry in thinnest pachymetry proved to be the best parameter to characterize intereye corneal asymmetry in keratoconus. This variable had high accuracy and significantly better discriminating ability (AUROC: 0.99) for KC than posterior elevation (AUROC: 0.96), ThCT (AUROC: 0.94) or CCT (AUROC: 0.92) alone.
There is an increased intereye asymmetry in keratometry, pachymetry and posterior corneal elevation values in keratoconic patients compared to subjects with normal corneas. Keratoconus patients with more severe disease are also more asymmetric in their disease status which should be taken into account during clinical care.
[Show abstract][Hide abstract] ABSTRACT: Purpose:
To evaluate and compare the mechanical properties of anterior capsule openings performed with the continuous curvilinear capsulorhexis (CCC) technique and femtosecond laser capsulotomy (FLC) in ex vivo porcine lens capsule specimens.
Fresh porcine eyes were included in the study (CCC group, n = 50; FLC group, n = 30). The capsule openings were stretched with universal testing equipment until they ruptured. The rupture force and circumference stretching ratio were evaluated. The morphologic profile of the cut capsule edges was evaluated using scanning electron microscopy (SEM).
The average rupture force was higher in the CCC group (median: 155 mN; interquartile range [IQR]: 129 to 201 mN; range: 71 to 294 mN) than in the FLC group (median: 119 mN; IQR: 108 to 128 mN; range: 91 to 142 mN) (P < .01, Mann-Whitney U test). The average circumference stretching ratio in the CCC group was greater (median: 150%; IQR: 146% to 156%; range: 136% to 161%) than in the FLC group (median: 148%; IQR: 145% to 150%; range: 141% to 154%) (P = .0468, Mann-Whitney U test). When less than 71 mN, no capsular tear occurred in either group. When less than 91 mN, no capsular tear occurred in the FLC group, whereas at 91 mN, the probability of capsular tears was 9% for the CCC group. SEM examination found that the CCC group had smooth edges, whereas those of the FLC group were gently serrated.
According to the current results in a porcine eye model, FLC had less average resistance to capsule tear than CCC, but the weakest openings were seen in the CCC group.
No preview · Article · Oct 2014 · Journal of refractive surgery (Thorofare, N.J.: 1995)
[Show abstract][Hide abstract] ABSTRACT: The mechanical behaviour of zonular fibres greatly affects the accommodation process in mammalian eyes. This paper introduces a detailed measurement procedure for the purpose of obtaining the force-displacement diagram necessary to evaluate the mechanical properties of porcine zonular fibres in situ. It is a complex technique, keeping the integrity of the zonular bundles between the crystalline lens and the ciliary muscle cells. We present a brief description of the measurement procedure both in theory and in practice, along with the force-displacement diagrams acquired from a porcine sample group. The strengths of this newly developed method are the unequivocal force transmission between the sample and the transducer, and the intact connection between the ciliary body and the crystalline lens via zonular fibres. With the aid of these measurements, we define an estimated material model for the zonular apparatus both analytically and using the finite element method. The two different evaluation methods show close agreement in the calculated Young׳s modulus for the zonular fibres. The range of the calculated elastic modulus is 200-250kPa. This new measuring method is adaptable to human specimens. Despite its complexity, the entire procedure and the evaluation part are reproducible. The constitutive model aims to shed light on the mechanics of the accommodation process.
No preview · Article · Sep 2014 · Journal of Biomechanics
[Show abstract][Hide abstract] ABSTRACT: Purpose:
To evaluate femtosecond laser-assisted and manual clear corneal incisions and their effect on surgically induced astigmatism (SIA) and corneal higher-order aberrations (HOAs).
In a prospective randomized study, conventional phacoemulsification with a 2.8-mm clear corneal incision using a disposable keratome was performed in 20 eyes of 20 patients (manual group), and femtosecond laser-assisted cataract surgery with a 2.8-mm biplanar clear corneal tunnel created by a femtosecond laser (LenSx; Alcon Laboratories, Inc., Aliso Viejo, CA) was performed in 20 eyes of 20 patients (femtosecond laser group). Corneal topography readings and corneal wavefront aberrations (diameter: 9.0 mm) were obtained using a Scheimpflug camera (Pentacam HR; Oculus Optikgerate, Wetzlar, Germany) preoperatively and 3 months postoperatively.
There was no significant difference in SIA between the groups (femtosecond laser group: 0.47 ± 0.13 vs manual group: 0.41 ± 0.14; P = .218), but the axis deviation of the SIA axis from the previously planned axis was significantly smaller in the femtosecond laser group compared to the manual group (4.47°± 2.59° vs 7.38°± 4.72°, respectively; P = .048). Corneal HOAs increased significantly in both groups (femtosecond laser group: 0.13 ± 0.09 to 0.18 ± 0.12, P = .025; manual group: 0.13 ± 0.05 to 0.15 ± 0.05, P = .002), but preoperative and postoperative values did not differ significantly between them (P = .472 and .078, respectively). Lower-order and total corneal aberration values remained stable in both groups (P > .05).
There was no difference in SIA and induced HOAs between manual and femtosecond laser-created clear corneal incisions.
No preview · Article · Jul 2014 · Journal of refractive surgery (Thorofare, N.J.: 1995)
[Show abstract][Hide abstract] ABSTRACT: Femtosecond lasers represent a new frontier in cataract surgery. Since their introduction and first human treatment in 2008, a lot of new developments have been achieved. In this review article, the physical principle of femtolasers is discussed, together with the indications and side effects of the method in cataract surgery. The most important clinical results are also presented regarding capsulotomy, fragmentation of the crystalline lens, corneal wound creation, and refractive results. Safety issues such as endothelial and macular changes are also discussed. The most important advantage of femtolaser cataract technology at present is that all the important surgical steps of cataract surgery can be planned and customized, delivering unparalleled accuracy, repeatability, and consistency in surgical results. The advantages of premium lenses can be maximally used in visual and presbyopia restoration as well. The advantages of premium lenses can be maximally used, not only in visual, but in presbyopia restoration as well. Quality of vision can be improved with less posterior chamber lens (PCL) tilt, more centralized position of the PCL, possibly less endothelial damage, less macular edema, and less posterior capsule opacification (PCO) formation. This technological achievement should be followed by other technical developments in the lens industry. Hopefully this review article will help us to understand the technology and the results to demonstrate the differences between the use of femtolasers and phacoemulsification-based cataract surgery. The most important data of the literature are summarized to show ophthalmologists the benefits of the technology in order to provide the best refractive results to the patient.
[Show abstract][Hide abstract] ABSTRACT: Purpose:
To describe femtosecond laser cataract surgery and discuss the published peer-reviewed articles to have a fair evaluation of this new technology and its comparisons to conventional phacoemulsification surgery.
The technology information released in this article comes from the key individuals in each of the U.S. Food and Drug Administration-approved companies and from the available commercial information. Bibliographic research was performed in PubMed and MEDLINE for the published prospective or retrospective clinical studies.
The femtosecond laser has been reported to be safe intraoperatively and postoperatively, with less cornea and macula effect than conventional phacoemulsification. The incision is integrated, stable, and aberration free. Many studies reported the high precision of the capsulotomy over manual continuous curvilinear capsulorhexis, which favors less intraocular lens tilt, higher optical quality, and more accurate premium intraocular lens centration. The lens fragmentation is effective with significant reduction of the phacoemulsification power and effective phacoemulsification time. The refractive difference between femtosecond laser and standard phacoemulsification is minimal, with no difference in corrected distance visual acuity, but the optical quality and the internal aberrations results are significantly better for femtosecond laser phacoemulsification.
Femtosecond laser cataract surgery is a good addition to cataract surgery despite its few remarkable advantages among experienced phacoemulsification surgeons.
No preview · Article · Jun 2014 · Journal of refractive surgery (Thorofare, N.J.: 1995)
[Show abstract][Hide abstract] ABSTRACT: To analyze complications of femtosecond lasers used for cataract surgery.
Department of Ophthalmology Semmelweis University, Budapest, Hungary.
Intraoperative complications of the first 100 femtosecond laser-assisted (Alcon-Lensx, Inc.) cataract surgeries were collected. Possible complications of femtosecond capsulotomies and their management were also assessed.
The complications were as follows: suction break (2%), conjunctival redness or hemorrhage (34%), capsule tags and bridges (20%), anterior tear (4%), miosis (32%), and endothelial damage due to cut within the endothelial layer (3%). There were no cases of capsule blockage or posterior capsule tear. During the learning curve, there was no complication that would require vitrectomy. All complications occurred during the first 100 cases.
Femtosecond laser cataract surgery had a learning curve during the first 100 cases. With cautious surgical technique, the complications can be avoided. The femtosecond laser-assisted method was efficient and safe for cataract surgery.
Drs. Nagy, T. Juhász, and Slade are consultants to Alcon-Lensx, Inc. No other author has a financial or proprietary interest in any material or method mentioned.
No preview · Article · Jan 2014 · Journal of Cataract and Refractive Surgery
[Show abstract][Hide abstract] ABSTRACT: The aim of this study was to evaluate the balance and changes of corneal higher order aberrations (HOAs) after photorefractive keratectomy (PRK).
Myopic and myopic-astigmatic patients (89 eyes of 48 patients) were enrolled in this study. A PRK was performed using an Asclepion Meditec MEL 80 G flying-spot excimer laser. The mean ablation depth and diameter were 76.78 μm (±19.40 μm) and 6.0 mm (±0.06 mm), respectively. Before and 1 year after the surgery, uncorrected and best spectacle-corrected visual acuities were determined. Wavefront aberrations of the anterior [root mean square (RMS)-HOA anterior], posterior (RMS-HOA posterior), and total cornea (RMS-HOA total) were measured using a Scheimpflug Camera. Linear piecewise regression analysis was used for correlations between the ablation depth and aberration of the anterior corneal surface. The follow-up time was 1 year.
At baseline, RMS-HOA anterior proved to be significantly higher compared with RMS-HOA total (P < 0.001). After the PRK was performed, the RMS-HOA anterior (P < 0.001) and RMS-HOA total values (P < 0.001) increased significantly; however, RMS-HOA posterior values (P = 0.12) remained stable. Above an ablation depth of 76.78 μm, the RMS-HOA anterior increased 2.4-fold. Uncorrected and best spectacle-corrected visual acuities were 1.0 (20/20) in 95.5% and 98.8% of the patients 1 year postoperatively.
Aberrations of the posterior corneal surface seem to compensate for wavefront alterations of the anterior cornea, decreasing the amount of wavefront error regarding the total cornea in myopic patients. PRK induced increased HOAs with respect to the anterior corneal surface; however, the posterior surface remained stable. The increase in the HOAs was measured to be significantly larger above 76.78 μm photoablation depth.
[Show abstract][Hide abstract] ABSTRACT: Analysis of the femtosecond laser refractive lens surgery corneal incision configuration and corneal higher-order aberration (HOA) effect from the first postoperative day.
High-resolution anterior segment optical coherence tomography was used to assess 20 eyes undergoing femtosecond laser refractive lens surgery with 2.2-mm minimal incision. The primary incision (tri-planar) actual length, cord length, surface angle, surface irregularity, and regional pachymetry values and the secondary incision (uni-planar) length, angle, surface irregularity, and pachymetry values were analyzed. Hartmann-Shack aberrometer was used to assess corneal HOAs to correlate the effect. Assessment was done preoperatively and 1 month postoperatively.
The actual length, cord length, and surface angle means for the primary incision in the first postoperative day and month were 1.50 ± 0.1 and 1.47 ± 0.2 mm (P = .5), 1.41 ± 0.1 and 1.42 ± 0.2 mm (P = .8), and 27° ± 4° and 23° ± 5° (P = .07), respectively. The length and surface angle for the secondary incision in the first postoperative day and month were 1.17 ± 0.01 and 1.04 ± 0.1 mm (P = .05) and 52° ± 3° and 42° ± 5° (P = .007). The regional pachymetry values for the primary and secondary incisions were significantly increased in the first postoperative day and then significantly decreased after 1 month. All irregularities occurred in the posterior surface (endothelium): 2 cases of posterior gap (first day) and 1 case of posterior retraction (first month). The HOAs had not significantly changed preoperatively and after 1 month.
The femtosecond laser refractive lens surgery incision is stable and does not significantly change the HOA. [J Refract Surg. 2013;29(9):590-595.].
No preview · Article · Sep 2013 · Journal of refractive surgery (Thorofare, N.J.: 1995)
[Show abstract][Hide abstract] ABSTRACT: To report the anterior segment imaging characteristics after femtosecond laser assisted cataract surgery.
Cataract surgery was performed with the LenSx femtosecond laser (Alcon-LenSx Inc., Aliso Viejo, CA) in 40 eyes of 40 patients. The laser was programmed to perform a 4.5-mm capsulorhexis, a cross-pattern fragmentation of the nucleus, a 2.8-mm main incision, and a 1.0-mm side-port incision. The anterior segment was then analyzed using the Visante OCT anterior segment program (Zeiss-Meditec AG, Jena, Germany).
The preoperatively set treatment parameters correlated well with the achieved results. For the capsulorhexis, the femtosecond laser cut was programmed to start 350 μm behind the anterior lens capsule and OCT measured 377 ± 55.3 μm. Nucleus fragmentation was programmed to start 750 μm in front of the posterior capsule and end 550 μm behind the anterior capsule, and OCT measured 794 ± 111 and 568 ± 147 μm, respectively. The diameter of the capsulorhexis measured by OCT was 4.54 ± 0.2 mm, compared to the 4.5 mm programmed.
Anterior segment OCT imaging was able to detect the tissue changes within the lens after femtosecond laser capsulorhexis and nucleus fragmentation. The measured values correlated well with the planned treatment parameters.
No preview · Article · Feb 2013 · Journal of refractive surgery (Thorofare, N.J.: 1995)
[Show abstract][Hide abstract] ABSTRACT: The development of femtosecond (FS) lasers in ophthalmology has been reviewed elsewhere (Chaps. 3 and 4). Their widespread application in corneal refractive surgery is one of the factors that led to an overall improvement in the clinical results of LASIK during the decade from 1995 to 2005, when rates of postoperative 20/20 UCVA increased from approximately 50–60 % to nearly 90 %. Similar to early stage corneal refractive surgery, rates of postoperative 20/20 UCVA in refractive cataract surgery currently stand at around 50–60 %, affecting both distance and near corrections [1–3].