From Simple Liquids to Surgical Instruments: On the History of Ophthalmo-Viscosurgical Devices (OVD)

Nowadays, OVDs are regarded as standard tools in ophthalmic surgery. Their discovery and development started about 70 years ago, in 1934, with isolating hyaluronic acid as the substance o f the vitreous body o f the human eye. Sodium Hyaluronate was the first substance used as an OVD and is now the most widely used material for OVDs used in ophthalmic surgery. It has become “the gold standard” to which all other viscoelastics are compared. Since the introduction of viscoelastic substances in the 1970s the properties of these agents have improved the quality o f anterior segment surgery. Therefore OVDs had — and still have — a great impact on the success of ophthalmic surgery — especially o f cataract surgery and intraocular lens implantation. In vivo studies have proven that the molecular and chemical structure of hyaluronic acid is ideal. Interactions between molecules and receptor tissues and inflammatory and immunogenic reactions have also been studied extensively. This article shows the historical development o f the different substances used nowadays and their properties.Preparaty wiskoelastyczne są obecnie uważane za standardowe narzędzia w operacjach okulistycznych. Ich odkrycie i rozwój zostały poprzedzone wyizolowaniem w 1934 roku kwasu hialuronowego z ciała szklistego ludzkiego oka. Hialuronian sodu był pierwszą substancją używaną w charakterze preparatu wiskoelastycznego i obecnie jest najpowszechniej używanym materiałem wiskoelastycznym w operacjach okulistycznych, stając się wzorcem, do którego porównywane są inne substancje wiskoelastyczne. Od momentu zastosowania w latach siedemdziesiątych materiały te, dzięki swoim właściwościom, przyczyniły się do poprawy wyników operacyjnych w przednim odcinku oka. Preparaty wiskoelastyczne miały i nadal mają wielki wpływ na powodzenie zabiegów okulistycznych, a zwłaszcza operacji usunięcia zaćmy i wszczepienia sztucznej soczewki wewnątrzgałkowej. Badania in vivo wykazały, że struktura molekularna i chemiczna kwasu hialuronowego jest idealna. Badane były również wzajemne oddziaływania między kwasem hialuronowym a tkankami oka oraz reakcje zapalne i immunologiczne. Ten artykuł przedstawia historię rozwoju obecnie stosowanych materiałów wiskoelastycznych oraz ich właściwości.Andrzej Grzybowsk

Semi‐Automated Quantification of Retinal and Choroidal Biomarkers in Retinal Vascular Diseases: Agreement of Spectral‐Domain Optical Coherence Tomography with and without Enhanced Depth Imaging Mode

Background: We compared with and without enhanced depth imaging mode (EDI) in semi-automated quantification of retinal and choroidal biomarkers in optical coherence tomography (OCT) in patients with diabetic retinopathy (DR) or retinal vein occlusion (RVO) complicated by macular edema. We chose to study three OCT biomarkers: the numbers of hyperreflective foci (HF), the ellipsoid zone reflectivity ratio (EZR) and the choroidal vascularity index (CVI), all known to be correlated with visual acuity changes or treatment outcomes. Methods: In a single examination, one eye of each patient (n = 60; diabetic retinopathy: n = 27, retinal vein occlusion: n = 33) underwent macular 870 nm spectral domain-OCT (SD-OCT) B-scans without and with EDI mode. Semi-automated quantification of HF, EZR and CVI was applied according to preexisting published protocols. Paired Student’s t-test or Wilcoxon rank-sum test was used to test for differences in subgroups. Intraclass correlation coefficient (ICC) and Bland–Altman plots were applied to describe the agreement between quantification in EDI and conventional OCT mode. The effect of macular edema on semi-automated quantification was evaluated. Results: For the entire cohort, quantification of all three biomarkers was not significantly different in SD-OCT scans with and without EDI mode (p > 0.05). ICC was 0.78, 0.90 and 0.80 for HF, EZR and CVI. The presence of macular edema led to significant differences in the quantification of hyperreflective foci (without EDI: 80.00 ± 33.70, with EDI: 92.08 ± 38.11; mean difference: 12.09, p = 0.03), but not in the quantification of EZR and CVI (p > 0.05). Conclusion: Quantification of EZR and CVI was comparable whether or not EDI mode was used. In conclusion, both retinal and choroidal biomarkers can be quantified from one single 870 nm SD-OCT EDI image

Binocular function to increase visual outcome in patients implanted with a diffractive trifocal intraocular lens

Background: To evaluate binocular visual outcome for near, intermediate and distance compared to monocular visual outcome at the same distances in patients implanted with a diffractive trifocal intraocular lens (IOL). Methods: The study comprised of 100 eyes of 50 patients that underwent bilateral refractive lens exchange or cataract surgery with implantation of a multifocal diffractive IOL (AT LISA tri 839MP, Carl Zeiss Meditech, Germany). A complete ophthalmological examination was performed preoperatively and 3 month postoperatively. The main outcome measures were monocular and binocular uncorrected distance (UDVA), corrected distance (CDVA), uncorrected intermediate (UIVA), and uncorrected near visual acuities (UNVA), keratometry, and manifest refraction. Results: The mean age was 59.28 years ± 9.6 [SD] (range 44–79 years), repectively. There was significant improvement in UDVA, UIVA, UNVA and CDVA. Comparing the monocular results to the binocular results there was a statistical significant better binocular outcome in all distances (UDVA p = 0.036; UIVA p < 0.0001; UNVA p = 0.001). The postoperative manifest refraction was in 86 % of patients within ± 0.50 [D]. Conclusions: The trifocal IOL improved near, intermediate, and distance vision compared to preoperatively. In addition a statistical significant increase for binocular visual function in all distances could be found. Trial registration German Clinical Trials Register (DRKS) DRKS0000783

Optical and material analysis of opacified hydrophilic intraocular lenses after explantation: a laboratory study

Background: The opacification of hydrophilic intraocular lenses (IOLs) is a very rare complication in terms of absolute numbers. We report on the analyses of opacified Euromaxx ALI313Y and ALI313 IOLs (Argonoptics, Germany) using light and scanning electron microscopy, X-ray spectroscopy and optical bench analysis. Methods: Opacified Euromaxx ALI313Y and ALI313 IOLs were explanted after patients presented with a decrease in visual acuity. The explants were sent to our laboratory and examined using light and scanning electron microscopy. The composition of the deposits was analysed using X-ray spectroscopy. The optical quality of the intraocular lens (IOL) was assessed using the OptiSpheric IOL PRO optical bench (Trioptics GmbH Wedel, Germany). Modulation transfer function (MTF) was measured at all spatial frequencies and United States Air Force (USAF) 1951 resolution target pictures were documented. Results: Macroscopically, the entire optic was opacified in all IOLs. Light and scanning electron microscopy revealed numerous fine, granular, crystalline-like deposits, which were always distributed in a line parallel to the anterior and posterior surfaces of the IOLs. X-ray spectroscopy could prove the deposits consisted of Calcium and Phosphate. Measurements in the optical bench showed deterioration of MTF values at all spatial frequencies and the USAF target pictures demonstrated a significant reduction of brightness as well as resolution with the opacified IOLs. Conclusions: The calcification of hydrophilic IOLs only occurs rarely. The exact chemical composition of the deposits can be assessed by means of X-ray spectroscopy. Optical quality analysis of the explanted Euromaxx ALI313Y and ALI313 IOLs showed significant reduction of MTF values, which was confirmed by USAF target pictures

Two-Photon Vision in Age-Related Macular Degeneration: A Translational Study

The recently introduced term “two-photon vision” relates to the visual perception resulting from a simultaneous absorption of two photons by photoreceptors. In this study, we determined two-photon retinal sensitivity in age-related macular degeneration (AMD) and compared it that in normal aging. Microperimetry was performed with visible (white) light and infrared (IR) light, which was perceived as green in the two-photon stimulation. In total, 45 subjects were included with one (better) eye studied. Furthermore, best-corrected visual acuity (VA) and ocular straylight were assessed. AMD resulted in decreased median (interquartile range) logMAR VA, i.e., 0.15 (0.05; 0.24), which in normal eyes was −0.02 (−0.06; 0.02). The two groups showed comparable straylight levels. Sensitivity to IR light was significantly lower in the AMD group (p < 0.001): 8.3 (7.4, 9.3) dB than in controls 10.7 (9.7, 11.2) dB. AMD also significantly affected visible light sensitivity (p < 0.001): 14.0 (11.0; 15.5) dB vs. 18.0 (16.3; 18.9) dB. Notably, the two-photon approach yielded a lower data spread. In conclusion, AMD considerably impairs retinal sensitivity measured in the single- and two-photon realm. However, two-photon-vision microperimetry may improve the testing accuracy and offer an additional diagnostic parameter (beyond VA measurements) for retinal function assessment

In vitro optical quality measurements of three intraocular lens models having identical platform

Background: With recent advances in technology and introduction of new intraocular lens (IOL) models, surgeons today have the opportunity to choose from various optical designs, which can influence the postoperative quality of vision. In our laboratory study, we compared the optical quality of three different IOLs that use the identical platform and are produced by the same manufacturer. The study included two diffractive multifocal IOLs, a bifocal and a trifocal one, as well as a monofocal IOL. Methods: Three IOL models: monofocal CT ASPHINA 409 M, diffractive bifocal AT LISA 809 M, and diffractive trifocal AT LISA Tri 839MP (Carl Zeiss Meditec AG, Germany) were assessed for optical quality by measuring modulation transfer function (MTF) and Strehl Ratio (SR) values at pupil sizes of 3.0 and 4.5 mm on the OptiSpheric® IOL PRO (Trioptics GmbH, Germany). The United States Air Force (USAF) Target images were also recorded to comfirm the optical performance qualitatively. Results: For far focus at 50 lp/mm and 3.0 mm pupil size, MTF value of the monofocal lens (MTF = 0.798) was 1.8-fold and 2.1-fold better than the bifocal (MTF = 0.446) and the trifocal (MTF = 0.382) IOLs, respectively. For near focus, bifocal IOL (MTF = 0.265) was 1.4-fold better than trifocal IOL (MTF = 0.187), while for intermediate focus, the trifocal IOL (MTF = 0.148) was 1.7-fold better than the bifocal IOL (MTF = 0.086). For the same pupil size, total sum of light loss amounted to 5.2% for the monofocal, 16.0% for the bifocal and 6.0% for the trifocal IOL. For a larger pupil, the amount of light loss increased significantly for the multifocal IOLs. Conclusions: The monofocal IOL performed the best for far, the bifocal IOL for near and the trifocal IOL for intermediate focus. While the monofocal IOL created the least amount of light loss for both pupil sizes, the trifocal IOL created less than half the amount of light loss than the bifocal IOL for small pupil. For large pupil, however, less light scatter was observed for the bifocal than the trifocal IOL

Ab interno gel implant in patients with primary open angle glaucoma and pseudoexfoliation glaucoma

Purpose: To compare efficacy and safety results of an ab interno gel implant in patients with pseudoexfoliation glaucoma (PXG) and primary open angle glaucoma (POAG). Methods: Retrospective analysis of the medical records of 110 consecutive eyes with open angle glaucoma who had received a XEN45 gel implant between March 2014 and June 2015. Intraocular pressure course, number of glaucoma medications, the need for additional intervention (including needling) and complications were evaluated until 12 months postoperatively. Results: Data of 67 eyes with POAG and 43 eyes with PXG were analyzed. At 12 months postoperatively, the mean IOP had significantly decreased by 54.0% from preoperatively 31.85 ± 8.5 mmHg to 13.99 ± 2.6 mmHg in the POAG group, (p = 0.000; Wilcoxon test), and by 55.2% from 31.63 ± 9.0 mmHg to 13.28 ± 3.1 mmHg in the PXG group (p = 0.000; Wilcoxon test). The mean number of anti-glaucoma medications had significantly decreased from 3.25 ± 0.8 at baseline to 0.3 ± 0.7 medications at 12 months postoperatively in POAG eyes (p = 0.000; Wilcoxon test), and from 3.05 ± 1.0 to 0.3 ± 0.6 medications in PXG eyes (p = 0.000; Wilcoxon test). Hypotony (IOP ≤ 6 mmHg) was observed in 2 POAG eyes (3.0%) and in 5 PXG eyes (11.7%) at 1 month but normalized in all eyes at 12 months postoperatively. Severe complications were not observed. No statistically significant differences were found between PXG eyes and POAG eyes. Conclusion: Our data indicate that the XEN45 gel implant provides significant and comparable reduction in IOP and anti-glaucoma medication during the one-year follow-up period in POAG as well as PXG eyes. This suggests that it may be a noteworthy alternative to traditional filtering procedures in patients with POAG and PXG respectively

Effects of ranibizumab (Lucentis®) and bevacizumab (Avastin®) on human corneal endothelial cells

Background: Ingrowth of newly formed blood and lymph vessels (angiogenesis) from the limbus region into the cornea can be treated successfully by subconjunctival application of antiangiogenic agents. Currently, there are several angiogenesis inhibitors from various manufacturers available, such as vascular endothelial growth factor (VEGF) antibodies. The aim of the study was to investigate potential cytotoxic effects of two anti-VEGF agents, ranibizumab (Lucentis®) and bevacizumab (Avastin®) on the human corneal endothelium. Methods: Human donor corneas, not suitable for corneal transplantation, were organ-cultured in the presence of either ranibizumab (Lucentis®) or bevacizumab (Avastin®) at different concentrations (group 1: 250 μg / ml, group 2: 25 μg / ml, group 3: 2.5 μg / ml) for a period of up to 4 weeks. Microscopic imaging for endothelial cell counting, detection of morphologic alterations of the endothelium, and molecular biology testing (Enzyme-linked Immunosorbent Assay [ELISA]) for metabolic changes was performed. Results: Background-corrected results showed neither a significant lactate dehydrogenase (LDH) change with increasing culturing time nor a significant difference between ranibizumab (Lucentis®) and bevacizumab (Avastin®) treatment. The endothelial cell density revealed also no statistically significant difference between the two treatment groups with ranibizumab (Lucentis®) and bevacizumab (Avastin®) at all concentrations tested in this study. Conclusions: In this study, the anti-angiogenic agents ranibizumab (Lucentis®) and bevacizumab (Avastin®) demonstrated no cytotoxic effects on the corneal endothelium of human organ-cultured donor corneas over the limited study time period of 4 weeks. However, based on the study design (in-vitro) and the limited follow-up period, no conclusions on potential long-term effects can be drawn

Prospective comparative study of tolerance to refractive errors after implantation of extended depth of focus and monofocal intraocular lenses with identical aspheric platform in Korean population

Background: To evaluate the clinical outcomes of extended depth of focus (EDOF) and monofocal intraocular lenses (IOLs) that share identical aspheric platform and compare their visual acuity tolerance to postoperative refractive errors. Methods: This non-randomized, prospective comparative study included 120 eyes undergoing cataract surgery with implantation of either Tecnis ZCB00 IOL (Abbott Medical Optics Inc., Santa Ana, CA) (monofocal group: 60 eyes of 30 patients) or Tecnis Symfony IOL (Abbott Medical Optics, Inc.) (EDOF group: 60 eyes of 30 patients). Monocular and binocular visual outcomes, changes in refraction, defocus curve, contrast sensitivity, and perception of photic phenomena (Halo &amp; Glare Simulator; Eyeland Design Network, Vreden, Germany) were evaluated 3 months postoperatively. To compare the refractive tolerance, each group was divided into three subgroups according to the postoperative uncorrected distance visual acuity (UDVA) and postoperative spherical equivalent (SE). Results: In the EDOF group, the mean 3-months postoperative monocular UDVA, intermediate (UIVA), and near (UNVA) visual acuities were 0.03 ± 0.07, 0.09 ± 0.15, and 0.24 ± 0.16 logMAR, respectively. A total of 100, 96.55, and 68.97% of eyes in the EDOF group achieved binocular UDVA, UIVA, and UNVA values of 0.20 logMAR or better, respectively. In respect to refractive tolerance, the EDOF group showed higher SE values and statistically significantly better mean UDVA than the monofocal group in all subgroups, with UDVA of − 0.013 and 0.028 logMAR for EDOF and monofocal groups (p = 0.037), respectively, in the subgroup where SE was within ±0.50 D, UDVA of 0.004 and 0.048 logMAR for EDOF and monofocal groups (p = 0.046), respectively, in the subgroup where SE was within − 1.00 D, and UDVA of 0.020 and 0.083 logMAR for EDOF and monofocal groups (p = 0.026), respectively, in the subgroup where SE was more than − 1.00 D. The mean patient satisfaction scores for spectacle-free distance, intermediate, and near visual acuities were 86.0, 85.0, and 66.0, respectively. Conclusions: The EDOF IOL provided excellent postoperative visual outcomes in far and intermediate distances, with high patient satisfaction rate. Regarding the postoperative refractive tolerance to SE, the Tecnis Symfony IOL showed better tolerance to residual postoperative refractive error than the monofocal IOL with the same material and optical platform

Hydrophilic intraocular lens opacification after posterior lamellar keratoplasty - a material analysis with special reference to optical quality assessment

Background: Laboratory analysis and optical quality assessment of explanted hydrophilic intraocular lenses (IOLs) with clinically significant opacification after posterior lamellar keratoplasty (DMEK and DSAEK). Methods: Thirteen opacified IOLs after posterior lamellar keratoplasty, 8 after descemet stripping automated endothelial keratoplasty (DSAEK), 3 after descemet membrane endothelial keratoplasty (DMEK) and 2 after both DSAEK and DMEK were analysed in our laboratory. Analyses included optical bench assessment for optical quality, light microscopy, scanning electron microscopy (SEM) and energy dispersive X-Ray spectroscopy (EDS). Results: In all IOLs the opacification was caused by a thin layer of calciumphosphate that had accumulated underneath the anterior optical surface of the IOLs in the area spared by the pupil/anterior capsulorhexis. The calcifications lead to a significant deterioration of the modulation transfer function across all spatial frequencies of the affected IOLs. Conclusions: The instillation of exogenous material such as air or gas into the anterior chamber increases the risk for opacification of hydrophilic IOLs irrespective of the manufacturer or the exact composition of the hydrophilic lens material. It is recommended to avoid the use of hydrophilic acrylic IOLs in patients with endothelial dystrophy that will likely require procedures involving the intracameral instillation of air or gas, such as DMEK or DS(A)EK