Tamer Tandogan

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

BackgroundThe 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.MethodsOpacified 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.ResultsMacroscopically, 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.ConclusionsThe 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.

Clinical Evaluation of Reading Performance Using the Salzburg Reading Desk With a Refractive Rotational Asymmetric Multifocal Intraocular Lens.

PURPOSE To evaluate functional results and reading performance using the Salzburg Reading Desk after implantation of a sector-shaped near-embedded, rotational asymmetrical multifocal intraocular lens (IOL) and a multifocal toric IOL with a +3.00 diopter (D) near addition. METHODS In a prospective study, the LentisMplus and Mplus toric IOLs (Oculentis GmbH, Berlin, Germany) were implanted in 34 eyes of 18 patients at the University Eye Hospital of Heidelberg. Uncorrected and corrected distance visual acuity (UDVA, CDVA) and uncorrected and corrected near visual acuity (UNVA, CNVA) were evaluated using standardized visual acuity charts (ETDRS). The Salzburg Reading Desk was used to analyze unilateral and bilateral uncorrected and corrected reading acuity, reading distance, reading speed, and the smallest log-scaled print size that could be read effectively at a set (40 cm/80 cm) and subjective chosen near and intermediate distance. RESULTS Postoperatively, the median UDVA was 0.08 logMAR (20/25 Snellen) and the median CDVA was 0.01 logMAR (20/20 Snellen). The median UNVA was 0.12 logMAR (20/25 Snellen) and the median CNVA was 0.03 logMAR (20/20 Snellen). The median uncorrected reading acuity measured with the Salzburg Reading Desk for near distance at 40 cm was 0.18 logMAR (20/32 Snellen). The subjectively preferred near distance was 39 cm and revealed similar visual acuity results. The best reading acuity for intermediate distance with a median of 0.22 logMAR (20/32 Snellen) was achieved at a median distance of 62 cm. CONCLUSIONS Reading performance of the multifocal IOL corresponded for near standardized and individual distance, whereas reading function was better at the patients preferred intermediate distance. [J Refract Surg. 2016;32(8):526-532.].

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

BackgroundLaboratory analysis and optical quality assessment of explanted hydrophilic intraocular lenses (IOLs) with clinically significant opacification after posterior lamellar keratoplasty (DMEK and DSAEK).MethodsThirteen 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).ResultsIn 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.ConclusionsThe 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.

Clinical Evaluation of an Extended Depth of Focus Intraocular Lens With the Salzburg Reading Desk

BACKGROUND Clinical evaluation of an extended depth of focus (EDOF) intraocular lens (IOL) regarding visual performance at various distances, reading performance on an electronic reading desk, and depth of focus on the defocus curve. METHODS In this prospective study, 30 eyes of 15 patients who received the Tecnis Symfony IOL (Abbott Medical Optics, Inc., Santa Ana, CA) were examined 3.60 ± 1.54 months postoperatively. Uncorrected and corrected distance (UDVA and CDVA), uncorrected and distance-corrected intermediate (UIVA and DCIVA), and uncorrected and distance-corrected near (UNVA and DCNVA) visual acuity were determined. The defocus curve was performed with distance correction. Furthermore, the reading acuity at the preferred near and intermediate distances was measured with consideration of the reading distance, speed, and print size. A subjective questionnaire was also administered. RESULTS Results showed a median UDVA of 0.03 logMAR or 20/21.43 Snellen (range: 0.44 to -0.18 logMAR or 20/55.08 to 20/13.21 Snellen), UNVA of 0.20 logMAR or 20/31.70 Snellen (range: 0.46 to 0.00 logMAR or 20/57.68 to 20/20 Snellen), and UIVA of -0.03 logMAR or 20/18.67 Snellen (range: 0.14 to -0.18 logMAR or 20/27.61 to 20/13.21 Snellen). The improved performance at intermediate distance was confirmed by an uncorrected reading acuity of 0.09 logMAR or 20/24.61 Snellen (range: 0.36 to 0.00 logMAR or 20/45.82 to 20/20.00 Snellen) at a preferred intermediate distance of 64.10 cm (range: 52.0 to 75.0 cm). The defocus curve showed an extended range of visual acuity of 0.10 logMAR or better between 1.00 and -1.50 diopters. CONCLUSIONS The EDOF IOL design provided a wide range of improved visual and reading function between far and intermediate distances and also improved near visual acuity. Patients reported a high rate of satisfaction and spectacle independence at the various distances. [J Refract Surg. 2017;33(10):664-669.].

High order aberration and straylight evaluation after cataract surgery with implantation of an aspheric,aberration correcting monofocal intraocular lens

AIM To evaluate the quality of vision in respect to high order aberrations and straylight perception after implantation of an aspheric, aberration correcting, monofocal intraocular lens (IOL). METHODS Twenty-one patients (34 eyes) aged 50 to 83y underwent cataract surgery with implantation of an aspheric, aberration correcting IOL (Tecnis ZCB00, Abbott Medical Optics). Three months after surgery they were examined for uncorrected (UDVA) and corrected distance visual acuity (CDVA), contrast sensitivity (CS) under photopic and mesopic conditions with and without glare source, ocular high order aberrations (HOA, Zywave II) and retinal straylight (C-Quant). RESULTS Postoperatively, patients achieved a postoperative CDVA of 0.0 logMAR or better in 97.1% of eyes. Mean values of high order abberations were +0.02±0.27 (primary coma components) and -0.04±0.16 (spherical aberration term). Straylight values of the C-Quant were 1.35±0.44 log which is within normal range of age matched phakic patients. The CS measurements under mesopic and photopic conditions in combination with and without glare did not show any statistical significance in the patient group observed (P≥0.28). CONCLUSION The implantation of an aspherical aberration correcting monofocal IOL after cataract surgery resulted in very low residual higher order aberration (HOA) and normal straylight.

In vitro comparative optical bench analysis of a spherical and aspheric optic design of the same IOL model

BackgroundTo analyse objective optical properties of the spherical and aspheric design of the same intraocular lens (IOL) model using optical bench analysis.MethodsThis study entailed a comparative analysis of 10 spherical C-flex 570 C and 10 aspheric C-flex 970 C IOLs (Rayner Intraocular Lenses Ltd., Hove, UK) of 26 diopters [D] using an optical bench (OptiSpheric, Trioptics, Germany). In all lenses, we evaluated the modulation transfer function (MTF) at 50 lp/mm and 100 lp/mm and the Strehl Ratio using a 3-mm (photopic) and 4.5-mm (mesopic) aperture.ResultsAt 50 lp/mm, the MTF values were 0.713/0.805 (C-flex 570 C/C-flex 970 C) for a 3-mm aperture and 0.294/0.591 for a 4.5-mm aperture. At 100 lp/mm, the MTF values were 0.524/0.634 for a 3-mm aperture and 0.198/0.344 for a 4.5-mm aperture. The Strehl Ratio was 0.806/0.925 and 0.237/0.479 for a 3-mm and 4.5-mm aperture respectively. A Mann–Whitney U test revealed all intergroup differences to be statistically significant (p < 0.01).ConclusionThe aspheric IOL design achieved higher MTF values than the spherical design of the same IOL for both apertures. Moreover, the differences between the two designs of the IOL were more prominent for larger apertures. This suggests that the evaluated IOL provides enhanced optical quality to patients with larger pupils or working under mesopic conditions.

LYSOPHOSPHATIDIC ACIDS AND AUTOTAXIN IN RETINAL VEIN OCCLUSION.

Purpose: To analyze the levels of lysophosphatidic acids (LPAs) and autotaxin (ATX) in undiluted vitreous of untreated patients with retinal vein occlusion (RVO). Methods: Sixty-four vitreous samples (40 RVO, 24 controls with idiopathic floaters) were analyzed in this retrospective case series using LC/MS for LPAs 16:0, 18:0, 18:1, 20:4, and ELISA kits or Luminex technology for ATX, angiopoetin-1 (ANG-1), interleukin-6 (IL-6), interleukin-7 (IL-7), interleukin-8 (IL-8), monocyte chemoattractant protein-1 (MCP-1), pigment epithelium-derived factor (PEDF), and vascular endothelial growth factor (VEGF). LPA and ATX levels were correlated with the visual acuity, central macular thickness (CMT), average retinal thickness (AvT), vitreal cytokine levels and with each other. Results: Levels of every LPA species tested and ATX were significantly increased in the vitreous fluid from all patients with RVO (total LPAs: 968.0 ± 842.3 nM; ATX: 2.5 ± 1.02 nM) compared with controls (total LPAs: 225.2 ± 292.8 nM, P < 0.0001; ATX: 1.9 ± 1.00 nM, P = 0.005). There were strong positive correlations between the vitreal levels of IL-6, IL-8, MCP-1, VEGF and LPAs. Conclusion: Levels of LPAs and ATX were positively correlated with proinflammatory cytokines and VEGF and might thus play an important role in the development of macular edema secondary to RVO.

Laboratory Evaluation of the Influence of Decentration and Pupil Size on the Optical Performance of a Monofocal, Bifocal, and Trifocal Intraocular Lens

PURPOSE To assess the influence of decentration and aperture size on the optical quality of different intraocular lenses (IOLs) of the same material, body design, and refractive power using standardized optical bench testing. METHODS Using an optical bench set-up, an aspheric monofocal (CT ASPHINA 409M; Carl Zeiss Meditec, Jena, Germany), an aspheric diffractive bifocal (AT LISA 809M; Carl Zeiss Meditec), and an aspheric diffractive trifocal (AT LISA 839M; Carl Zeiss Meditec) intraocular lens (IOL) were evaluated, each with the same distance power, body design, and material. Modulation transfer function (MTF) values were measured at spatial frequencies of 50 lp/mm and aperture sizes of 3 and 4.5 mm. Each IOL was measured while centered, then decentered by 0.25, 0.5, 0.75, and 1 mm. RESULTS MTF values for the monofocal IOL at far focus with 3- and 4.5-mm aperture size were 0.80/0.80 with maximum reduction to 0.77/0.73 for 1-mm decentration, respectively. Centered IOL MTFs of the bifocal and trifocal IOLs were lower for the far focus at 0.46/0.41 and 0.39/0.26, with reduction at 1-mm decentration to 0.35/0.25 and 0.25/0.18, respectively. Values for near focus of the bifocal and trifocal IOLs reduced from 0.27/0.31 and 0.19/0.18 to 0.2/0.21 and 0.12/0.13, respectively. The trifocal intermediate focus MTF reduced from 0.15/0.10 to 0.12/0.08. MTF values of all three lenses decreased significantly under all conditions with decentration of 0.5 to 0.75 mm. CONCLUSIONS Monofocal lenses were least negatively affected by decentration, with mean optical quality reduction of less than 10% for 1-mm decentration at physiological pupil sizes. For diffractive bifocal and trifocal lenses, optical quality at all distances was significantly reduced if decentration exceeded 0.75 mm, with intermediate focus showing the least reduction. [J Refract Surg. 2017;33(12):808-812.].

Impact of Indocyanine Green Concentration, Exposure Time, and Degree of Dissolution in Creating Toxic Anterior Segment Syndrome: Evaluation in a Rabbit Model

Purpose. To investigate the role of indocyanine green (ICG) dye as a causative material of toxic anterior segment syndrome (TASS) in an experimental rabbit model. Method. Eight eyes of four rabbits were allocated to this study. Capsular staining was performed using ICG dye, after which the anterior chamber was irrigated with a balanced salt solution. The effects of different concentrations (control, 0.25, 0.5, and 1.0%), exposure times (10 and 60 seconds), and the degree of dissolution (differently vortexed) were investigated. The analysis involved anterior segment photography, ultrasound pachymetry, prostaglandin assay (PGE2 Parameter Assay, R&D systems, Inc.), and scanning electron microscopy of each iris. Result. There was no reaction in the control eye. A higher aqueous level of PGE2 and more severe inflammatory reaction were observed in cases of eyes with higher concentration, longer exposure time, and poorly dissolved dye. Additionally, scanning electron microscopy revealed larger and coarser ICG particles. Conclusion. TASS occurrence may be associated with the concentration, exposure time, and degree of dissolution of ICG dye during cataract surgery.

In Vivo Imaging of Intraocular Fluidics in Vitrectomized Swine Eyes Using a Digital Fluoroscopy System

Purpose. To describe the characteristics of intraocular fluidics during cataract surgery in swine eyes with prior vitrectomy. Methods. We prepared three groups of enucleated swine eyes (nonvitrectomized, core, and totally vitrectomized). Irrigation and aspiration were performed (2.7 mm conventional sleeved phacosystem) using a balanced saline solution mixed with a water-soluble radiopaque contrast medium at 1 : 1 ratio. We imaged the eyes using a digital fluoroscopy system (DFS) during phacoemulsification and compared the characteristics of the intraocular fluid dynamics between the groups. Results. The anterior chamber depth (ACD) after the commencement of irrigation differed between groups (2.25 ± 0.06 mm; 2.33 ± 0.06 mm; 3.17 ± 0.11 mm), as well as the height of the fluid flowing from the anterior chamber into the posterior cavity that was identified by lifting up the iris to correct the infusion deviation syndrome (0.00 ± 0.00 mm; 0.41 ± 0.04 mm; 2.19 ± 0.35 mm). Conclusions. DFS demonstrated differences in fluid dynamics during phacoemulsification in swine eyes with or without prior vitrectomy. In completely vitrectomized eyes, the large ACD, which developed during phacoemulsification, could be reduced by lifting the iris and allowing the fluid to shift to the posterior cavity. Recognizing the differences in fluidics of vitrectomized eyes as compared to those of the nonvitrectomized eyes may reduce the frequency of intraoperative complications.