Bleb geometry and morphology after Preserflo Microshunt surgery: Risk factors for surgical failure.

PURPOSE: To investigate the possible risk factors for treatment failure in patients who had undergone Preserflo Microshunt (PMS) implantation, using anterior-segment optical coherence tomography (AS-OCT) to analyze the internal structures of the bleb. METHODS: The PMS blebs of 54 patients were evaluated with AS-OCT. A mathematical model was used to calculate the total filtering surface of the episcleral fluid cavity (EFC) and the hydraulic conductivity (HC) of the bleb wall. Complete and qualified success were defined as IOP between 6 and 17 mmHg with or without glaucoma medication. The relation between baseline characteristics and probability of bleb success was analyzed by bivariate and multivariate logistic regression. The main outcome measures were mean bleb wall thickness (BWT), reflectivity (BWR), HC, mean horizontal and vertical diameter and total filtering surface (TFS) of the EFC. RESULTS: Blebs from 74% patients were considered as complete success and 26% as failure. BWR and BWT increased linearly up to the first year in both groups. BWR was higher in the group failure (p = 0.02) and BWT in the group success (p<0.001). EFC was wider and shorter in the success group (p = 0.009, p = 0.03). Higher TFS showed a negative correlation with IOP (r = -0.4, p = 0.002). Higher baseline IOP was associated with success of PMS by multivariate analysis (p = 0.01). Mean HC, 0.034 ± 0.008 (µL/min)/mm2/mmHg, was negatively correlated with bleb surface (r = -0.5, p<0.0001) and wall´s thickness (r = -0.3, p = 0.01). CONCLUSIONS: AS-OCT revealed that successful PMS blebs could show either thick hyporreflective walls or wide filtering surfaces with thin capsules. A higher baseline IOP increased the probability of surgical success.

Comparison of the optical quality vision between real post-LASIK myopic laser surgery and the simulated implantation of a phakic IOL in low myopia.

A phakic intraocular lens (PIOL) of - 4.5 D was characterized from its wavefront aberration profile. A preclinical study was conducted using pre- and post-surgery data from four patients that had undergone myopic laser refractive surgery. All these patients would have needed a PIOL of - 4.5 D. Pre-surgery data were used to simulate the effect of a PIOL implantation. Post myopic refractive surgery data were used to calculate the post-LASIK eye model. Modulation transfer function (MTF), point spread function (PSF) and simulation of optotypes vision were obtained and compared. The PIOL did not worsen the optical quality of the eyes evaluated. High order Aberrations were always higher in the post-LASIK eye model. Optics quality trended to be better in PIOL implantation than post-LASIK surgery as pupil size increased.

Efficacy of astigmatic correction after femtosecond laser-guided cataract surgery using intraoperative aberrometry in eyes with low-to-moderate levels of corneal astigmatism.

PURPOSE: To evaluate the efficacy of astigmatic correction with two types of toric intraocular lenses (IOLs) after femtosecond laser-assisted cataract surgery (FLACS) in eyes with low-to-moderate corneal astigmatism using intraoperative aberrometry for optimizing the position of the toric IOL. METHODS: Retrospective study includes a total of 99 eyes of 73 patients with anterior keratomeric astigmatism ≤ 3 D and undergoing FLACS (Catalys, Johnson & Johnson Vision) with implantation of a monofocal (Ankoris, PhysIOL) or a multifocal toric IOL with the same platform (Pod FT, PhysIOL). In all cases, intraoperative aberrometry was used (Optiwave refractive analysis, ORA, system, Alcon). Visual and refractive outcomes were evaluated preoperatively and at 4 months after surgery with vector analysis of astigmatic changes. RESULTS: A total of 89.9%, 93.9% and 97.0% showed a postoperative sphere, cylinder and spherical equivalent within ± 0.50 D, respectively. Mean difference vector (DV) was 0.22 ± 0.27 D, mean magnitude of error (ME) was 0.13 ± 0.29 D, and mean angle of error (AE) was 1.52 ± 11.64°. Poor correlations of preoperative corneal astigmatism with DV (r = - 0.032, p = 0.833), ME (r = - 0.344, p = 0.001) and AE (r = - 0.094, p = 0.377) were found. Likewise, no statistically significant differences were found between monofocal and multifocal toric IOL subgroups in DV (p = 0.580), ME (p = 0.702) and AE (p = 0.499). CONCLUSIONS: The combination of FLACS and intraoperative aberrometry to optimize the position of a toric IOL allows a very efficacious correction of preexisting low-to-moderate corneal astigmatism.

Femtosecond laser-assisted capsulotomy for treatment of bilateral anterior capsule contraction.

A 51-year-old woman developed severe fibrosis and occlusion of the visual axis in 1 eye, maintaining a pinhole aperture in the fellow eye, 2 months after uneventful cataract surgery and implantation of a hydrophilic trifocal intraocular lens in the capsular bag. She had not exhibited any risk factor for anterior capsule contraction preoperatively. Femtosecond laser-assisted capsulotomy with a fluid-filled interface system was used to perform a simultaneous anterior capsulotomy in both eyes. Preoperative calculations of the incision depth of the capsulotomy were performed using optical coherence tomography (OCT) and adjusted intraoperatively with the OCT system of the femtosecond laser. The energy level used in the first eye was increased for the second eye (4 µJ to 6 µJ) because of severe capsulotomy tags that had to be cut with scissors. Despite the increase in energy, a free-floating capsulotomy could not be achieved in the second eye.

Effect of the Femtosecond Laser on an Intracorneal Inlay for Surgical Compensation of Presbyopia during Cataract Surgery: Scanning Electron Microscope Imaging.

PURPOSE: To investigate the effect of the femtosecond laser-assisted cataract surgery (FLACS) on porcine eyes implanted with a Kamra corneal inlay and to describe how the inlay may change the effect of the femtosecond laser on the lens. METHODS: FLACS was performed on six porcine eyes and a Kamra corneal inlay had been implanted, exploring the lens under the surgical microscope. Another Kamra corneal inlay was attached to the upper part of the transparent hemisphere used for calibration of the femtosecond laser. Capsulorhexis, arcuate incisions, and phacofragmentation were carried out. The Kamra corneal inlay was compared with a nontreated one using a scanning electron microscope (SEM), and the hemisphere was analyzed with a surgical microscope. RESULTS: Capsulorhexis and phacofragmentation were completed in all the porcine eyes, although accuracy to determine the exact effect on the lens was not possible to achieve. The effect of the femtosecond laser on the PMMA hemisphere through the Kamra corneal inlay showed the capsulorhexis was placed outside the outer margin of the inlay and a sharply sculpted fragmentation pattern with a three-dimensional (donut-shaped) annulus untreated beneath it. SEM images of the nontreated and the treated inlays were comparable. No ultrastructural changes were found in the treated Kamra corneal inlay. CONCLUSIONS: FLACS can be performed with a Kamra corneal inlay for surgical compensation of presbyopia without the risk of damaging the inlay. The Kamra corneal inlay acts as a screen that avoids the laser to reach the areas beneath its shadow, but not the exposed areas of the lens.

Porcine Model to Evaluate Real-Time Intraocular Pressure During Femtosecond Laser Cataract Surgery.

PURPOSE: To investigate the changes in intraocular pressure (IOP) in porcine eyes during femtosecond laser-assisted cataract surgery using a liquid-optic interface system. MATERIALS AND METHODS: Femtosecond laser cataract surgery with the Catalys™ was performed on freshly enucleated porcine eyes in Oftalvist Moncloa, Madrid, Spain. Capsulorhexis and lens fragmentation were completed in all the eyes without complications. IOP was measured with a reusable blood pressure transducer connected by direct cannulation to the anterior chamber, recording data before suction (basal), at the beginning of the suction phase, every five seconds during femtosecond procedure and after the removal of the suction ring from the eye. RESULTS: Nine porcine eyes were used in this study. Basal IOP before suction was 5.67 ± 2.39 mmHg, rising to 20.33 ± 4.18 mmHg at the beginning of the suction phase (p < 0.001). During femtosecond procedure, pressure reached a value of 19.74 ± 4.31 mmHg, remaining stable during the entire process. The IOP recorded prior to removal of the suction ring was 21.00 ± 6.93 mmHg, returning to basal values in all the eyes after the suction ring was removed, with no statistical differences between basal and post-suction IOPs. Total femtosecond procedure time was 125.9 ± 15.9 s. CONCLUSIONS: Real-time IOP can be measured during surgery using a transducer connected to the anterior chamber. The results showed a significant increase in IOP during the procedure due to the pressure exerted by the suction ring but not by the effect of the femtosecond laser.