A Novel 3D High Resolution Imaging Method Using Correlative X-Ray and Electron Microscopy to Study Neodymium-Doped Yttrium Aluminum Garnet Laser-Induced Defects in Intraocular Lenses.

INTRODUCTION: Cataract extraction is the most frequently performed ophthalmological procedure worldwide. Posterior capsule opacification remains the most common consequence after cataract surgery and can lead to deterioration of the visual performance with cloudy, blurred vision and halo, glare effects. Neodymium-doped yttrium aluminum garnet (Nd:YAG) laser capsulotomy is the gold standard treatment and a very effective, safe and fast procedure in removing the cloudy posterior capsule. Damaging the intraocular lens (IOL) during the treatment may occur due to wrong focus of the laser beam. These YAG-pits may lead to a permanent impairment of the visual quality. METHODS: In an experimental study, we intentionally induced YAG pits in hydrophilic and hydrophobic acrylic IOLs using a photodisruption laser with 2.6 mJ. This experimental study established a novel 3D imaging method using correlative X-ray and scanning electron microscopy (SEM) to characterize these damages. By integrating the information obtained from both X-ray microscopy and SEM, a comprehensive picture of the materials structure and performance could be established. RESULTS: It could be revealed that although the exact same energies were used to all samples, the observed defects in the tested lenses showed severe differences in shape and depth. While YAG pits in hydrophilic samples range from 100 to 180 µm depth with a round shape tip, very sharp tipped defects up to 250 µm in depth were found in hydrophobic samples. In all samples, particles/fragments of the IOL material were found on the surface that were blasted out as a result of the laser shelling. CONCLUSION: Defects in hydrophilic and hydrophobic acrylic materials differ. Material particles can detach from the IOL and were found on the surface of the samples. The results of the laboratory study illustrate the importance of a precise and careful approach to Nd:YAG capsulotomy in order to avoid permanent damage to the IOL. The use of an appropriate contact glass and posterior offset setting to increase safety should be carried out routinely.

Neodymium-doped yttrium aluminum garnet (Nd: YAG) laser treatment in ophthalmology: a review of the most common procedures Capsulotomy and Iridotomy.

Nowadays, lasers are used in various medical fields. Ophthalmology was the first medical specialty to utilize lasers in patient treatment and still remains the leading medical field that uses laser energy for both therapeutic and diagnostic purposes. The neodymium: yttrium-aluminum-garnet (Nd: YAG) laser is one of the most common lasers used in ophthalmology. It is a solid-state laser with a wavelength of 1064 nm that works on the principle of photodisruption. Since its introduction in ophthalmology over 40 years ago, it has found various applications, mainly for procedures where cutting or disruption of ocular tissue is required. Compared to surgical alternatives, the use of Nd: YAG lasers on ocular tissue is minimally invasive. In this review, we focus on the two most common ophthalmic applications of Nd: YAG laser - laser peripheral iridotomy and posterior capsulotomy. The history of the techniques, current trends, potential complications, and the prognosis for future use is discussed.

Video analysis of optic-haptic-interaction during hydrophobic acrylic intraocular lens implantation using preloaded injectors.

OBJECTIVE: To compare the optic-haptic interaction of different hydrophobic acrylic IOLs after using six preloaded injectors. METHODS: We reviewed the video-recordings of procedures on a total of 388 eyes that underwent phacoemulsification and intraocular lens (IOL) implantation. For six preloaded injectors: multiSert (Hoya Surgical Optics) [System 1], TECNIS Simplicity (Johnson & Johnson Vision) [System 2], TECNIS iTec (Johnson & Johnson Vision) [System 3], AutonoMe (Alcon, Laboratories) [System 4], Bluesert (Carl Zeiss Meditec) [System 5], and Prosert (OphthalmoPro GmbH) [System 6], we noted in each case the time of IOL delivery and made a descriptive observation of IOL insertion and optic-haptic-interaction. RESULTS: We defined standard haptic behavior where the haptics emerged "folded" from the injector and quickly recovered their pre-implantation appearance. The incidence where the leading haptic emerged in a deformed way for System 1 was 20%, System 2: 19%, System 3: 14%, System 4: 56%, System 5: 24% and System 6: 5%. For trailing haptic deformed behavior, the incidence was 36%, 6%, 4%, 8%, 18% and 2%, respectively for Systems 1 to 6. Optic-haptic adhesion occurred in 2% of cases for System 1, 44% for System 2, 52% for System 3, 48% for System 4, and 11% for System 6 (P < 0.05). Adhesion was not found with System 5. CONCLUSIONS: We observed different deformed behavior for leading and trailing haptics in the six preloaded systems, some systems had as much as 52% optic-haptic adhesion.

Impact of Decentration and Tilt on Spherical, Aberration Correcting, and Specific Aspherical Intraocular Lenses: An Optical Bench Analysis.

INTRODUCTION: The human eye is not optically symmetrical, and very few intraocular lens (IOLs) are perfectly centered in the eye. That is why contrast sensitivity can degrade in some conditions, especially in low light. In an optical bench analysis, we compare spherical (A), aberration correcting (B), and specific aspherical lenses (C) in terms of impact of decentration and tilt on the modulation transfer function as well as the simulated overall quality with USAF test targets. MATERIAL AND METHODS: The OptiSpheric IOL PRO2 was used to measure the optical performance of IOLs (A, B, C). In order to assess the optical quality of the IOLs, the optical quality parameters for the aperture size of 3.0 mm and 4.5 mm at the IOL plane were assessed. Through Frequency Modulation Transfer Function (MTF) and Strehl Ratio (SR) values, as well as the "US Airforce 1951 resolution test chart images" as qualitative simulation, were analyzed. All measurements (ISO) were repeated and done for centered, decentered (1 mm), and tilted (5°) IOLs. RESULTS: Centered: The MTF (mean) at 50 lp/mm (IOL A, B, C) with 3.0-mm aperture was 0.794/0.716/0.797 (ISO-1 cornea) and 0.673/0.752/0.723 (ISO-2 cornea) and with 4.5-mm aperture 0.728/0.365/0.751 (ISO 1) and 0.276/0.767/0.505 (ISO 2). The SR (mean) with 3.0-mm aperture was 0.763/0.829/0.898 and with 4.5-mm aperture 0.228/0.386/0.432. Decentered by 1 mm: The MTF (mean) at 50 lp/mm with 3.0-mm aperture was 0.779/0.459/0.726 (ISO 1) and 0.695/0.381/0.662 (ISO 2). The MTF (mean) at 50 lp/mm with 4.5-mm aperture was 0.732/0.348/0.653 (ISO 1) and 0.355/0.069/0.346 (ISO 2). The SR (mean) with 3.0-mm aperture was 0.829/0.543/0.397 and with 4.5-mm aperture was 0.259/0.145/0.192. Tilted by 5°: The MTF (mean) at 50 lp/mm with 3.0-mm aperture was 0.731/0.705/0.751 (ISO 1) and 0.623/0.727/0.732 (ISO 2). The MTF (mean) at 50 lp/mm with 4.5-mm aperture was 0.579/0.406/0.701 (ISO 1) and 0.277/0.512/0.429 (ISO 2). The SR (mean) with 3.0-mm aperture was 0.539/0.478/0.514 and with 4.5-mm aperture was 0.262/0.136/0.201. CONCLUSION: Aberration correcting IOLs perform best when perfectly centered. The optical performance of aberration correcting IOLs can be markedly downgraded by misalignment. The examined ZO optic performed well in decentration and tilt. The ZO concept seems to be a good alternative to aspheric lenses, as it achieves to combine benefits of spherical and aspheric intraocular lenses. There is no perfect IOL, but fitting and choosing the right one for the individual case seems to be crucial to take advantage of benefits and minimize disadvantages. This is why knowledge of optical properties is also mandatory for the surgeon.

Analysis of YAG Laser-Induced Damage in Intraocular Lenses: Characterization of Optical and Surface Properties of YAG Shots.

PURPOSE: To assess differences in neodymium:yttrium aluminum garnet (Nd:YAG)-induced defects in hydrophilic and hydrophobic intraocular lenses (IOLs) and describe optical and surface properties of YAG shots/pitting. Describing and measuring the iatrogenic produced defects should achieve higher awareness on this topic and change the mindset of such a trivial procedure to be proceeded with more caution and calmness in the future. MATERIALS: Twelve IOLs from different manufacturers made of hydrophilic and hydrophobic materials were evaluated before and after treatment with the Nd:YAG laser. Microscopy and environmental scanning electron microscopic (ESEM) images were used to visually analyze the defects. Additionally, wavefront measurements were taken for power mapping and Raman spectroscopy was performed. Vertical and horizontal dimensions of the defects were analyzed and compared, and Raman line scans assessed the changes in the chemical structure in the defect area of the IOL. RESULTS: Microscopically, pitting of the surface could be observed in both lens types. Defects in hydrophobic lenses appeared bigger and were visible with less magnification than in hydrophilic lenses. Similar results were obtained with ESEM images where the defects in hydrophobic IOLs seemed to be frayed while defects in hydrophilic IOLs were of circular shape. Raman spectroscopy revealed deeper defects in hydrophobic lenses. Vertical dimensions of the defects were statistically significant (p = 0.036) and greater in hydrophobic materials while horizontal dimensions did not reach significance (p = 0.056). The area of chemical changes was greater than the visible defect area and smaller in hydrophilic than that in hydrophobic materials. CONCLUSION: Nd:YAG seems to have greater impact on hydrophobic IOL materials as that damage was greater and more frayed than that in hydrophilic materials. Moreover, there seems to be larger, distinctive damage area in IOLs (with chemical changes in the material) than that is visually recognizable. Therefore, a very cautious approach is recommended when performing capsulotomy, as defects in the surface structure can occur. This might come along with problems in quality of vision in monofocal and primarily premium IOLs (multifocal, enhanced depth of focus, and toric IOLs), dependent on the size, dimension, and position in the IOL. YAG capsulotomy should not be considered trivial but should be carried out with precision and without time pressure, just like surgery itself.

[Safety First - Evaluation of IOL Injector Systems]. / Sicherheit geht vor ­ Evaluation von IOL-Injektorsystemen.

INTRODUCTION: Improvements in cataract surgery led to the availability of preloaded IOL delivery systems. These are expected to reduce overall surgery time while being safe and effective. This study evaluates the safety and manageability of the 2-component autoloading system SAFELOADER® (HumanOptics AG, Erlangen, Germany) and compares these results to two other systems. MATERIAL AND METHODS: A total of 167 eyes were enrolled to this single centre prospective study. In 67 eyes, the IOLs were implanted via the SAFELOADER system, in 50 eyes via another preloaded system (TECNIS iTec® Preloaded Delivery System, Johnson & Johnson Vision, Santa Ana, CA, USA) and in 50 eyes via a manual implantation system (UNFOLDER® Platinum 1 Series Delivery System, Johnson & Johnson Vision, Santa Ana, CA, USA). IOL preparation time and implantation time were measured in seconds for each device. The OR workflow and handling of the device by the surgeon and the scrub nurse were rated by a grading system from 1 (very good) to 5 (very poorly). RESULTS: The SAFELOADER and iTec were faster and handier than the manually loaded system. Regarding preparation time, the SAFELOADER with a median of 6.5 (5.3 - 6.9) seconds (s) was about one second slower (p < 0.0001) than iTec with 5.2 s (4.5 - 6.5). Both were significantly faster (p < 0.0001) than the UNFOLDER with 26.9 s (20.6 - 30.1). Implantation time was similar between SAFELOADER with 7.2 s (5.3 - 8.6), iTec with 7.3 s (5.9 - 8.3) and UNFOLDER with 7.2 s (5.9 - 7.6). When graded, SAFELOADER 2.0 (1.0 - 3.0) and iTec 1.0 (1.0 - 3.0) were significantly (p < 0.0001) better than the manual system 5.0 (3.0 - 5.0) with respect to overall OR workflow. The surgeon rated the handling of SAFELOADER and iTec (both median 1.0; 1.0 - 2.0) similarly and significantly better (p < 0.001) than that of the UNFOLDER 2.5 (1.0 - 4.0). For the scrub nurse, SAFELOADER 1.0 (1.0 - 2.0) was significantly better (p < 0.0001) in handling than iTec 2.0 (1.0 - 3.0) and UNFOLDER 4.0 (2.0 - 5.0). CONCLUSION: The 2-component autoloading system SAFELOADER® is intuitive in handling, fast and effective in implantation of the IOL and very safe.

["The Big Five" - Cataract Surgery Under Multiple Ocular Comorbidity: Customised Approach to Prevent Complications]. / "The Big Five" ­ Kataraktchirurgie bei multiplen okulären Komorbiditäten: individuelle Vorgehensweise zur Komplikationsvermeidung.

The co-occurence of 5 diseases (cataract, Fuchs dystrophy, pseudoexfoliation syndrome, age-related macular degeneration and dry eye syndrome) can lead to massive impairment of visual acuity. Our case series show that cataract surgery can lead to an enormous profit in visual rehabilitation and therefore in daily routine.

Geometry of Modern Presbyopia-Correcting Intraocular Lenses and Changes in Haptic-Capsular Bag Behavior According to Compression and Different Well Diameters: A Bench Study Using Computed Tomography.

INTRODUCTION: The geometry of an intraocular lens (IOL), the design of the haptics, and the optic-haptic junction play a role in initial and long-term visual outcome after cataract surgery. Knowledge of the behavior of an implant in the capsular bag and under compression is of major importance. Our laboratory experiment analyzed in-depth the geometry of acrylic, single-piece, premium, presbyopia-correcting intraocular lenses and changes in haptic-capsular bag relationships according to capsular bag size using a range of compression well diameters. METHODS: One hydrophilic (RayOne Trifocal® RAO603F) and three hydrophobic intraocular lenses (AcrySof IQ PanOptix®, Synergy DFR00V™, and AT ELANA 841P®) were scanned with computed tomography (CT) in a dry, uncompressed state for quantitative analyses of haptic and optic-haptic junction (OHJ) dimensions and qualitative assessment of geometry. In the second part of the experiment, CT was performed after sample placement into a series of compression wells (9.0, 10.0, 11.0, 11.5 mm) for analyses of length of contact (LoC) between the haptics and the wells. Axial alignment and haptic-capsular bag relationships were assessed. RESULTS: The qualitative and quantitative evaluations highlighted differences in haptic and OHJ geometry and dimensions across the samples. The mid-zone of the optic was thickest in the hydrophilic sample (RayOne Trifocal® RAO603F) with a maximum of 0.880 mm compared to the thinnest hydrophobic sample (AT ELANA 841P®) with 0.564 mm. The AT ELANA 841P® showed the largest OHJ surface area (3.86 mm2) and OHJ volume (0.60 mm3) of the hydrophobic samples. The TECNIS Synergy DFR00V™ showed the thickest OHJ (0.51 mm), while the AcrySof IQ PanOptix® showed the thinnest OHJ (0.21 mm). The LoC values decreased with increasing well size for all tested samples. The AT ELANA 841P® showed the largest LoC and largest contact zones of hydrophobic samples in all wells. CONCLUSION: The laboratory experiments highlight differences in the haptics, the OHJ geometric characteristics, and behavior of samples in different well diameters. The results support the idea that specific IOL designs may have advantages or disadvantages depending on anatomical dimensions. We cannot make any classification or rating (good versus bad) for clinical practice on the basis these experimental results, as many other factors play a role. However, knowledge of IOL geometry seems important to select the best option in each individual case.

Examining Penetration and Residual Depth in Modern Acrylic Foldable Intraocular Lenses: A Laboratory Study Using Differential Interference Contrast Microscopy to Compare Hydrophilic and Hydrophobic Materials.

Introduction The material of modern intraocular lenses must meet the highest standards and fulfill various requirements. It is crucial that the material shows the best biocompatibility and should be flexible for an uncomplicated implantation process through small corneal incisions but also sufficiently rigid for good stability and centering in the capsular bag. In addition, the optic must remain clear for life and retain the best optical properties. Methods In this laboratory experiment, we performed scratch tests for the mechanical assessment of acrylic intraocular lenses. The aim was to determine differences in the behavior in regard to the manufacturing process and water content of hydrophilic and hydrophobic acrylic intraocular lenses. The scratch tests were performed using a Nano Scratch Tester. A conical indenter with a tip radius of 1 µm and a cone angle of 90° was selected to scratch the samples at three different constant loads of 5, 10, and 15 mN, respectively. The scratch length was set to 100 µm at a scratch speed of 200 µm/min. Hydrophilic and hydrophobic acrylic intraocular lenses (with different water content) were tested. Results The results showed that for sample A (hydrophilic acrylate), the penetration depth increases steadily with increasing force from 25-30 µm (5 mN) to 28-33 µm (10 mN) and 34-37 µm (15 mN). The penetration depths during the scratches seem to be load-dependent. In sample B (hydrophobic acrylate), the same forces lead to steadily increasing penetration depths: 25-30 µm (5 mN), 40-44 µm (10 mN), and 54-57 µm (15 mN). The evaluation of the residual depth showed much lower values for all samples. In the hydrophilic, softer samples (A), the residual depth was between 1 µm and 4 µm. In the hydrophobic, more solid, samples (B), the residual depth was more pronounced with values between 5 µm and 17 µm. The plastic influence and deformation zone seemed to be wider for the hydrophobic samples than for the hydrophilic samples. Conclusion The laboratory experiment confirms that modern, acrylic intraocular lenses are sensitive to scratches/touch, and penetration depths during scratching depend on the load. The remaining depths after the scratches are significantly lower and show a load dependence. The deforming zone was higher in the hydrophobic acrylates than in the hydrophilic acrylates. However, the results confirm that damage can occur with hydrophobic and hydrophilic acrylic materials, depending on the force applied. Therefore, careful handling during the preparation and implantation process is crucial to prevent permanent defects.

VIVEX: A Formula for Calculating Individual Vitreous Volume: A New Approach Towards Tailored Patient Dosing Regime in Intravitreal Therapy.

INTRODUCTION: Personalized medicine and patient-tailored drug dosing have been substantiated through thousands of clinical studies, demonstrating their safety and efficacy. The principle: "as much as necessary, as little as possible" is widely spread. Quantities and doses are therefore adjusted individually. This is not the case for intravitreal injections in the context of retinal diseases. Intravitreal injections are not adjusted in relation to the vitreous volume. The vitreous body is described as "approx. 4 cm3" in the literature. METHODS: In this retrospective observational study, we included 72 eyes of patients who had undergone magnetic resonance imaging (MRI) of the orbit and biometry measurements of the anterior chamber depth (ACD) and axial length. After segmentation of the volume data, the vitreous volume was extracted by voxel integration, and a simple prediction model was derived to determine the vitreous volume from the axial length (AL) measurement with AL3·π/6·(0.76 + 0.012·(AL-24). This is the volume of a sphere AL3·π/6 and a correction term 0.76 + 0.012·(AL-24) to account for the portion of the vitreous in the entire globe and the proportional increase of the vitreous portion for long (myopic) eyes. RESULTS: Emmetropic eyes with an axial length of 22.50-23.50 mm had a vitreous volume of around 4.5-5.5 cm3. Myopic eyes with an axial length of 30.00 mm had a calculated vitreous volume of 9.0-10.0 cm3. Hypermetropic eyes with an axial length of 20.00 mm showed a vitreous volume of 3.0-4.0 cm3. CONCLUSIONS: By implementing the new calculation formula on the IOLCON website, it will be easy to get the exact individual vitreous volume. The data could be used by retinal surgeons prior to surgery. The knowledge of anatomical dimensions and exact individual vitreous volume seems to be important for gas and silicone oil fillings. With the newly derived knowledge, multicentric studies can evaluate the impact of the dose in intravitreal therapies. Patient-tailored dosing could prevent side effects and improve effectiveness.

Calculated Drug Concentrations in Currently Available Intravitreal Therapies: Determination of Dilution Factor and Deviation From Recommended Doses.

In ophthalmology, intravitreal therapies are currently not personalized/customized and are not adjusted to the individual vitreous volume. With reference to the recently published calculation formula for a more accurate estimation of the vitreous body, we determined the dose of intravitreal medication for different vitreous volumes and compared them with the average volume. Using the axial length of the eye, the formula for the vitreous volume exact (VIVEX) can provide a more accurate indication of the vitreous volume in individual cases than an assumed standard volume of 4 mL. The concentration of active substances in small eyes may be twice as high as that in normal-sized emmetropic eyes. In contrast, large eyes may show less than half of the recommended drug concentration. The calculated concentrations of the investigated intravitreal drugs in small and large eyeballs showed impressive differences with large deviations from the recommended doses. Further systematic studies should follow to find out whether this has any impact on the effectiveness or side effects of the injected drugs.

Image Contrast and Spectral Transmission of Presbyopia-Correcting Intraocular Lenses: Evaluating the Impact of Nd:YAG Laser Associated Defects.

PURPOSE: Neodymium yttrium aluminum garnet (Nd:YAG) laser capsulotomy is considered gold standard in the treatment of posterior capsule opacification (PCO). In this laboratory study, we measured spectral transmission to evaluate the image contrast and analyze the impact of Nd:YAG associated defects in presbyopia-correcting intraocular lenses (IOLs). METHODS: Two hydrophobic, acrylic IOLs as classic multifocal lenses with diffractive ring segments and different amount of near addition (A, B), one hydrophilic, trifocal IOL (C), one sector-shaped, plate haptic IOL (D) and one hydrophobic, enhanced depth of focus (EDOF) IOL (E) were studied. Measurements included surface topography characterization, United States Air Force resolution test chart (USAF) analysis, spectral transmittance measurements and through focus contrast measurement. Measurements were done with unaltered samples, damages (n = 7) were intentionally created in the central 3.5 mm zone using a photodisruption laser (2.0 mJ) and measurements were repeated. RESULTS: Significant differences were shown between unmodified samples and samples with YAG pits. The YAG-pits decreased the image contrast and spectral transmission and changed results of USAF test images. The imaging contrast decreased to 66%, 64%, 60%, 52% and 59% with the YAG shots in samples (A-E). The light transmission decreased to 88%, 87%, 92%, 79% and 91% (A-E) on average between 400 nm to 800 nm. In all IOLs a reduction of the relative intensity of transmitted light was observed. CONCLUSION: The image performance of all tested presbyopia-correcting IOLs is significantly influenced and disturbed by YAG-pits. The intensity of transmitted light is reduced in the wavelength between 450-800 nm. USAF test targets show worse results compared to unmodified samples and contrast is significantly deteriorated. No ranking/rating among tested IOLs should be made as many other factors play a role in real world scenario. High care should be taken when performing Nd:YAG capsulotomy on premium IOLs to avoid any damages.

Incorrectly Focused Neodymium:Yttrium-Aluminum-Garnet (Nd:YAG) Laser Beam Leads to Massive Destructive Effects in Small-Aperture (Pinhole) Intraocular Lenses.

INTRODUCTION: Pinhole intraocular lenses (IOLs) were developed to improve reading by compensating for loss of accommodative function. The IC-8® Apthera™ is a small-aperture presbyopia-correcting IOL that combines the proven principle of small-aperture optics with an aspheric monofocal lens to deliver a continuous range of vision for patients with cataracts from distance to near vision. Posterior capsule opacification is the most common sequela after cataract surgery. It is effectively treated by laser capsulotomy. However, if the laser beam is incorrectly focused, the IOL can be permanently damaged (pits/shots). METHODS: In this experimental study, yttrium-aluminum-garnet (YAG) pits were purposefully created. Defects were analyzed and compared between the periphery of the ring in the clear area of the hydrophobic acrylic lens and at the carbon black (CB)-polyvinylidene fluoride (PVDF) filtering component (FilterRing™) of the pinhole lens. All defects were made using identical settings/energy levels (2.6 mJ). The damage induced to the IC-8® Apthera™ IOL was examined by low-magnification images, light microscopy, scanning electron microscopy, and micro-computed tomography (micro-CT). RESULTS: YAG defects in the carbon black filter ring were much more severe than those in the clear zone due to the high absorption of the carbon black. Massive defects and destruction of the lens with tearing out of fragments and particles were observed. The missing volume calculated from the micro-CT reconstruction was 0.266 mm3, which is 1.6% of the entire IOL volume, or more than 1000 times the volume damaged in the largest shot in the periphery. CONCLUSION: Based on the results, we highly recommend using the lowest possible energy levels, posterior offset setting, and circular pattern for maximum safety when performing laser capsulotomy with pinhole implants. Care should be taken to avoid creating irreversible iatrogenic defects that may affect overall quality. The safest area for performing capsulotomy seems to be the periphery of the ring segment. Video available for this article.

Clinical Performance of New Enhanced Monofocal Intraocular Lenses: Comparison of Hydrophobic C-loop and Hydrophilic Plate-Haptic Platform.

INTRODUCTION: Enhanced monofocal intraocular lenses (IOLs) represent a new type of lens, which should lead to a very good distance vision similar to monofocal IOLs and an improved intermediate vision without increasing the risk for photic phenomena. METHODS: The aim of this clinical observation/registry study was to directly compare two different IOL platforms (hydrophilic acrylic L-333 (group A) vs hydrophobic acrylic AN6Q (group B)) with the same enhanced monofocal optic principle but different material and haptic design in clinical routine. A total of 102 cataract cases (51:51) were included in the study. Groups A and B were similar regarding demographics, age (71.6 ± 9 years for L-333 and 73.6 ± 8 years for AN6Q) and their calculated IOL power (20.9 ± 2.0 D for L-333 and 21.5 ± 3.4 D for AN6Q). Spherical equivalent (SE), (un)corrected distance, intermediate visual acuity, the surgeons' experience and patient feedback were assessed postoperatively. RESULTS: SE improved significantly in the AN6Q group, while the L-333 group showed a slightly smaller standard deviation postoperatively. In group A the uncorrected distance visual acuity (UDVA) improved from pre-op (0.43 ± 0.16 logMAR) to 1 month post-op (0.06 ± 0.04 logMAR) significantly and in group B from pre-op (0.54 ± 0.19 logMAR) to (0.05 ± 0.06 logMAR) postoperatively. Both groups showed excellent outcomes for distance without negative side effects. On testing uncorrected intermediate vision (80 cm) with Radner charts, 80% reached line 5 (0.0 logRAD) with fewer than one mistake and 10% reached line 4 (- 0.1 logRAD) in group A; 74% reached line 5 with fewer than one mistake and 4% reached line 4 in group B. CONCLUSION: Both IOL models (groups A and B) provided satisfying results regarding implantation behaviour, refractive error, visual acuity and overall patient satisfaction. The haptic design might influence the outcome of refractive error. Long-term follow-up data should be considered in multicentre studies to further characterize both platforms and to optimize IOL power calculation (constants, surgeon factor). It was shown that the enhanced monofocal optic can provide good visual acuity for far distance and improve intermediate distance. This type of new monofocal optic design, which however must be strictly separated from typical refractive/diffractive multifocal, presbyopia-correcting lenses, could be a good option in standard cataract care.

Implantable vision-enhancing devices and postoperative rehabilitation in advanced age-related macular degeneration.

Age-related macular degeneration (AMD) results in progressive vision loss that significantly impacts patients' quality of life and ability to perform routine daily activities. Although pharmaceutical treatments for AMD are available and in clinical development, patients with late-stage AMD are relatively underserved. Specialized rehabilitation programs and external low-vision aids are available to support visual performance for those with advanced AMD; but intraocular vision-improving devices, including implantable miniature telescope (IMT) and intraocular lens (IOL) implants, offer advantages regarding head motion, vestibular ocular reflex development, and depth perception. IMT and IOL technologies are rapidly evolving, and many patients who could benefit from them remain unidentified. This review of recent literature summarizes available information on implantable devices for improving vision in patients with advanced AMD. Furthermore, it discusses recent attempts of developing the quality of life tests including activities of daily life and objective assessments. This may offer the ophthalmologist but also the patient a better possibility to detect changes or improvements before and after surgery. It is evident that surgery with new implants/devices is no longer the challenge, but rather the more complex management of patients before and after surgery as well as the correct selection of cases.

Nano-Indentation to Determine Mechanical Properties of Intraocular Lenses: Evaluating Penetration Depth, Material Stiffness, and Elastic Moduli.

INTRODUCTION: Intraocular lenses (IOL) should remain in the eye for life after implantation into the capsular bag during cataract surgery. The material must meet various requirements. It is crucial that the material has the best biocompatibility, and it should be flexible and soft for best possible implantation process but also sufficiently stable and stiff for good centering in the eye and posterior capsule opacification prevention. METHODS: In this laboratory experiment, we used nano-indentation for the mechanical assessment of three hydrophobic acrylic (A, B, C), three hydrophilic acrylic (D, E, F), and one silicone (G) intraocular lens. We wanted to determine whether some react more sensitively to touching/handling than others. The indentation elastic modulus and the creep were obtained from the force displacement curve. For measuring penetration depth and testing of possible damage to the intraocular lenses, the samples were measured at room temperature. A 200-µm-diameter ruby spherical tipped indenter was used for all the tests. Indentations were made to three different maximum loads, namely 5 mN (milli Newton), 15 mN, and 30 mN and repeated three times. RESULTS: The lowest penetration depth (12 µm) was observed with IOL B. However, IOL A, D, and F showed similar low penetration depths (20, 18, and 23 µm, respectively). Lenses C and E showed slightly higher penetration depths of 36 and 39 µm, respectively. The silicone lens (G) showed the greatest penetration depth of 54.6 µm at a maximum load of 5 mN. With higher maximal loads (15 and 30 mN) the penetration depth increased significantly. Lens C, however, showed the same results at both 15 and 30 mN with no increase of penetration depth. This seems to fit well with the material and manufacturing process of the lens (lathe-cut). During the holding time of 30 s at constant force all six acrylic lenses showed a significant increase of the creep (CIT 21-43%). Lens G showed the smallest creep with 14%. The mean indentation modulus (EIT) values ranged from 1 to 37 MPa. IOL B had the largest EIT of 37 MPa, which could be caused by the low water content. CONCLUSION: It was found that results correlate very well with the water content of the material in the first place. The manufacturing process (molded versus lathe-cut) seems to play another important role. Since all included acrylic lenses are very similar, it was not surprising that the measured differences are marginal. Even though hydrophobic materials with lower water content showed higher relative stiffness, penetration and defects can also occur with these. The surgeon and scrub nurse should always be aware that macroscopic changes are difficult to detect but that defects could theoretically lead to clinical effects. The principle of not touching the center of the IOL optic at any time should be taken seriously.

Clear corneal incision, an important step in modern cataract surgery: a review.

A clear corneal incision (CCI) is the most commonly used entrance site in modern phacoemulsification cataract surgery. Despite some initial concerns about increased endophthalmitis rates through a self-sealing CCI, recent literature suggests that the risk of infection with proper wound construction and all other necessary precautions is minimal. The technique of creating a clear corneal incision has, with recent developments in corneal imaging, undergone critical appraisal leading to a better understanding of incision architecture. Many surgeons operate through smaller incisions, and they have a wide choice of surgical instruments to create their corneal incisions. The aim of this review is to discuss the history and the current status of clear corneal incision creation, the design and materials of surgical blades, and the current trends in manufacturing and sustainability. Although disposable instruments have some advantages and are very popular, recycling, if possible, and avoiding unnecessary plastic waste are important considerations. In any case, the step of CCI is a small one for the surgeon, but a big one for the eye. That is why it has to be done with the utmost precision and in-depth knowledge is important.

Geometry of Acrylic, Hydrophobic IOLs and Changes in Haptic-Capsular Bag Relationship According to Compression and Different Well Diameters: A Bench Study Using Computed Tomography.

INTRODUCTION: Characteristics of the haptics and optic-haptic junction (OHJ) of an intraocular lens (IOL) affect IOL position in the capsular bag, positional stability, and the development of posterior capsule opacification. Therefore, the haptics and OHJ have a role in determining initial and long-term visual outcomes after cataract surgery. Understanding differences in the haptics and OHJ of available IOLs and in the relationships between the haptics of each IOL and the capsular bag across a range of capsular bag sizes might inform selection of an IOL model for individuals. PURPOSE: To evaluate the geometry of five currently marketed, commonly used one-piece hydrophobic acrylic monofocal IOLs and changes in haptic-capsular bag relationships according to capsular bag size using a range of compression well diameters. METHODS: AcrySof SN60WF, CT LUCIA 621PY, enVista MX60, TECNIS ZCB00, and Vivinex XY1 IOLs were scanned with computed tomography (CT) in a dry, uncompressed state for quantitative analyses of haptic and OHJ dimensions and qualitative assessment of geometry. CT scanning was done after IOL placement into a series of compression wells (11.5, 11.0, 10.0, and 9.0 mm) for analyses of haptic angle of contact (AoC) and capsular bag contact (CBC). IOL axial alignment and haptic-capsular bag relationships were assessed on side-view and 3-dimensional top-view images, respectively. RESULTS: The qualitative and quantitative evaluations highlighted differences in haptic and OHJ geometry and dimensions across the five IOLs. All haptic dimensions (length, thickness, surface area, volume) and all OHJ dimensions (surface area and volume) were greatest for the CT LUCIA 621PY IOL. Compared to the IOL that had the smallest measurement for each parameter, the value for the CT LUCIA 621PY IOL was 31-91% larger. The lens with the largest OHJ surface area and volume showed values that were 500% and 240% greater than the corresponding values for the lens with the smallest OHJ surface area and OHJ volume. The AoC and CBC values decreased with increasing well size for all IOLs. The CT LUCIA 621PY had the greatest AoC and CBC values for all well sizes and the smallest percentage change in AoC and CBC comparing the values from the 9.0 mm and 11.5 mm wells. CONCLUSION: The in vitro evaluations in this study highlight differences in the haptic and OHJ geometric characteristics of the five IOLs studied. The collected evidence refutes opinions that all hydrophobic acrylic one-piece IOLs are the same and supports the idea that individual IOLs can have relative advantages and disadvantages that depend on the individual case. We believe the knowledge of geometry is necessary for the surgeon to have the opportunity to select the best "customized" option in the individual case as a result of anatomical conditions and secondary diagnoses. Our bench study shows how big the differences are in currently available monofocal hydrophobic acrylic lenses.

Evaluating Optical Quality of a New Hydrophilic Enhanced Monofocal Intraocular Lens and Comparison to the Monofocal Counterpart: An Optical Bench Analysis.

INTRODUCTION: The aim of the study was to analyze the optical properties of a new hydrophilic enhanced monofocal intraocular lens (IOL) using optical bench analysis and compare it with its monofocal counterpart. METHODS: This laboratory study investigates the enhanced monofocal intraocular lens (L-333) and the monofocal counterpart (L-313) IOL by Teleon Surgical, Spankeren, Netherlands on the optical bench, using OptiSpheric IOL PRO2 (Trioptics, Germany) in order to assess the optical quality according to ISO 11979 with ISO-2 Cornea. IOLs (power 22.0 D) were evaluated regarding through frequency modulation transfer function (MTF), Strehl ratio (SR), and through focus MTF at 50 lp/mm using a 3.0-mm and a 4.5-mm aperture. Tilt and decentration were applied. In addition, wavefront measurements were obtained using WaveMaster® IOL 2 device (Trioptics, Germany) and analyzed. RESULTS: Centered: The MTF (mean) at 50 lp/mm (L-333/L-313) with 3.0 mm aperture was 0.606/0.724 and with 4.5 mm aperture 0.330/0.409. The SR (mean) with 3.0 mm aperture was 0.586/0.809 and with 4.5 mm aperture 0.330/0.348. Decentered by 1 mm: The MTF (mean) at 50 lp/mm (L-333/L-313) with 3.0 mm aperture was 0.485/0.705 and with 4.5 mm aperture 0.255/0.374. The SR (mean) with 3.0 mm aperture was 0.457/0.739 and with 4.5 mm aperture 0.185/0.268. Tilted by 5 degrees: The MTF (mean) at 50 lp/mm (L-333/L-313) with 3.0 mm aperture was 0.577/0.657 and with 4.5 mm aperture 0.345/0.336. The SR (mean) with 3.0 mm aperture was 0.583/0.702 and with 4.5 mm aperture 0.269/0.237. In through focus MTF and aperture of 3.0 mm, the L-333 showed a peak of 0.41 with some enlarged depth of power of about 2 D. For the aperture of 4.5 mm, the MTF values of L-313 and L-333 were slightly reduced; L-333 showed an MTF peak of 0.23 and some reduced depth of power of about 1.5 D. Wavefront measurements showed no major aberrations for the L-313, while a combination of moderate increase in Z 4-0 and Z 6-0 with opposite sign was revealed for the L-333. CONCLUSION: The enhanced monofocal Lentis Quantum (L-333) produces some enlarged depth of focus by combining spherical aberration of different order and opposite sign. The Lentis Quantum performs very well in comparison to the aspherical monofocal counterpart owing to its optical design. Results with large apertures were sufficient too, suggesting that  the lens is a good option in eyes with a wide pupil and thus in refractive surgeries of young patients.

Removing residual cortical material during cataract surgery: Visco polishing and the grindstone effect as a new surgical technique.

PURPOSE: To describe a new technique for removing residual cortical material adjacent to posterior lens capsule during cataract surgery with the help of cohesive ophthalmic viscosurgical devices. METHODS: In this technique, if there are still cortical remnants and lens epithelial cells left after the routine irrigation-aspiration and polishing at the final steps of cataract surgery, the capsule is filled to about one-third with a highly viscous cohesive ophthalmic viscosurgical device. Rinsing is performed from the anterior chamber with the water jet directed tangentially to the ophthalmic viscosurgical device bolus and towards the posterior capsule, which creates a turbulence creating a "grindstone effect". The ophthalmic viscosurgical device bolus transforms into a ball and starts to rotate very quickly within the capsule, grinding away the cortical remnants. RESULTS: In the first series of 62 cases, there were no intra-operative or post-operative complications. At day 1 there was no corneal oedema and no hypertension of intraocular pressure. Visual outcomes were good with a mean best corrected distance visual acuity of -0.01 ± 0.11 logMAR. CONCLUSION: This technique appears to be effective and fast in removing persistent cortical remnants from the surface of the posterior capsule, while minimising risks such as capsule aspiration during irrigation/aspiration. There is limited pressure and mechanical force applied on the capsule; the anterior chamber and the corneal endothelium remain safe since the ophthalmic viscosurgical device stays inside the capsular bag to its high cohesiveness and molecular weight. More data on a larger cohort of patients is planned to confirm these results and evaluate long-term effects on posterior capsule opacification.