Early intraocular lens explantations: 10-year database analysis.

BACKGROUND: The aim of this study was to analyze the causes and characteristics of IOL explantation within the first year after primary implantation. METHODS: In this retrospective, cross sectional database study, a database consisting of over 2500 IOL explants sent from 199 national and international doctors over the past 10 years was analyzed. All IOLs explanted within the first year after implantation were included in this analysis. Explants with insufficient information as well as phakic and Add-on IOLs were excluded. Main outcome measures were the reason for explantation, the time between implantation and explantation, as well as IOLs' and patients' characteristics. Additionally, the explanted IOLs were microscopically and histologically analyzed, as required. RESULTS: Of all explanted IOLs from the database, 1.9% (n = 50) were explanted within the first year after implantation. The most frequent reasons for early IOL explantation were IOL dislocation (32%), visual intolerance (26%), opacification (20%), and intraoperative complications (16%). The time between implantation and explantation was the shortest in cases with intraoperative complications (1.5 ± 3.1 days), followed by IOL dislocation (90.9 ± 103.9 days), visual intolerance (98.3 ± 86.5 days), opacifications (253.5 ± 124.0 days) and other indications (249.7 ± 124.0 days). Calcification of hydrophilic IOLs was the main type of opacification (80%). Notably, seven IOLs required immediate intraoperative exchange due to an intraoperative crack in the optic or a torn off haptic. CONCLUSION: Indications for early IOL explantation were IOL dislocation, visual intolerance, opacification, and intraoperative complications. Especially intraoperative damages to the IOL and early calcification show a potential for improvement of affected IOLs and implantation systems.

Biomechanical Analysis of Tomographically Regular Keratoconus Fellow Eyes Using Corvis ST. / Biomechanische Analyse von tomografisch unauffälligen Keratokonus-Partneraugen mit dem Corvis ST.

BACKGROUND: Keratoconus is a bilateral, yet asymmetric disease. In rare cases, the second eye may show no signs of tomographic changes. The purpose of this study was to analyze the biomechanical characteristics in tomographically regular keratoconus fellow eyes. MATERIALS AND METHODS: This retrospective, consecutive case series analyzed 916 eyes of 458 patients who presented to our keratoconus clinic between November 2020 and October 2022. Primary outcome measures included best-corrected visual acuity (BCVA), tomographic Scheimpflug analysis using Pentacam AXL (Oculus, Wetzlar, Germany), and biomechanical assessment using Corvis ST (Oculus, Wetzlar, Germany). Tomographic changes were assessed via analysis of the anterior and posterior curvature, K-max, thinnest corneal thickness (TCT), the Belin/Ambrosio Deviation Display (BAD-D), and the ABCD-Grading. Biomechanical changes were analyzed using Corvis Biomechanical Index (CBI) and Tomographic Biomechanical Index (TBI). RESULTS: Of 916 eyes, 34 tomographically regular fellow eyes (7.4%) were identified and included in the analysis. Overall, the mean BCVA was - 0.02 ± 0.13 logMAR. Tomographic analysis showed mean K-max of 43.87 ± 1.21 D, mean TCT of 532 ± 23 µm, and mean BAD-D of 1.02 ± 0.43. Biomechanical analysis demonstrated mean CBI of 0.28 ± 0.26 and mean TBI of 0.34 ± 0.30. While normal CBI-values were observed in 16 (47%) of 34 eyes, only 13 eyes (38%) showed a regular TBI and only 7 eyes (21%) showed regular TBI and CBI. The sensitivity of CBI and TBI to detect a tomographically normal keratoconus fellow eye was 53% and 62%, respectively. CONCLUSION: A highly asymmetric corneal ectasia with regular tomographic finding in a fellow eye is rare among keratoconus patients. In such cases, a biomechanical analysis may be useful in detecting early signs of corneal ectasia. In our analysis, the TBI showed high sensitivity for detecting a biomechanical abnormality in tomographically regular fellow eyes.

Reversible Multifocality Achieved Through Polypseudophakia. / Reversible Multifokalität durch Polypseudophakie.

Simultaneous implantation of a monofocal or monofocal toric intraocular lens (IOL) into the capsular bag and a multifocal IOL into the ciliary sulcus, referred to as duet procedure, allows us to create multifocality that is more easily reversible than the implantation of a capsular bag-fixated multifocal IOL. The optical quality and results after the duet procedure are equivalent to those of a capsular bag-fixated multifocal IOL. Patients who cannot tolerate the side effects of multifocal optics or who develop an ocular condition leading to loss of function such as age-related macular degeneration (AMD) or glaucoma in the course of their lives may benefit from the reversibility of the procedure.

[Hydrophobic surface properties of hydrophilic acrylic lenses do not protect against calcification]. / Hydrophobe Oberflächeneigenschaften hydrophiler Acryllinsen schützen nicht vor Kalzifikation.

BACKGROUND: Opacification through calcification of hydrophilic acrylic intraocular lenses is a serious complication of cataract surgery, which usually results in explantation of the lens. In the process of calcification, the intraocular lens material plays a crucial role: calcification only occurs in hydrophilic acrylic lenses. Hydrophobic acrylic lenses show no crystal formation within the polymer. Hydrophilic acrylic lenses from some manufacturers have hydrophobic surface properties. The question arises as to what influence these surface properties have on the risk of calcification. OBJECTIVE: The present study investigated whether the hydrophobic surface properties of hydrophilic acrylic lenses can prevent calcification. MATERIAL AND METHODS: Using an electrophoretic in vitro model of calcification, two hydrophilic lenses with hydrophobic surface properties were compared to two hydrophilic lenses and a hydrophobic negative control to determine the risk of calcification. The lenses were then analyzed by optical microscopy, Alizarin Red and Von Kossa staining, scanning electron microscopy (SEM) and energy dispersive X­ray spectroscopy (EDX). RESULTS: All four hydrophilic lens models showed calcification within the polymer. No difference was found between the hydrophilic lenses and the hydrophilic lenses with hydrophobic surface properties in terms of crystal formation. The hydrophobic negative control showed no calcification. CONCLUSION: The investigation conducted in this study under standardized conditions could show that hydrophobic surface properties of hydrophilic acrylic lenses do not protect against calcium phosphate crystal formation within the polymer. There also is a risk of calcification in these lens models.

Development of a standardized in vitro model to reproduce hydrophilic acrylic intraocular lens calcification.

Opacification through calcification of hydrophilic acrylic intraocular lenses (IOL) is a severe complication after cataract surgery. Causing symptoms that range from glare through to severe vision loss, the only effective therapy is explantation of the opacified IOL so far. Although IOL calcification is a well-described phenomenon, its pathogenesis is not fully understood yet. The purpose of the current study was to develop a laboratory model to replicate IOL calcification. Calcification could be reproduced using a horizontal electrophoresis and aqueous solutions of calcium chloride and disodium hydrogen phosphate. The analysis of the in vitro calcified IOLs was performed using light microscopy, Alizarin Red and Von Kossa staining, scanning electron microscopy, energy dispersive x-ray spectroscopy and electron crystallography using transmission electron microscopy and electron diffraction. The presented laboratory model could be used to identify hydrophilic IOLs that are at risk to develop calcification and to assess the influence of associated risk factors. In addition, it can serve as a research tool to further understand this pathology.

Microscopic Characteristics of Late Intraocular Lens Opacifications.

CONTEXT.­: The increases in overall life expectancy and in lens surgeries performed on younger patients have resulted in a significant increase in the anticipated duration of artificial intraocular lenses (IOLs) in the eye. Thus, the physicochemical properties of the IOL become a critical issue, and several types of postoperative IOL opacifications have been reported. OBJECTIVE.­: To describe the microscopic characteristics of opacified IOLs. Glistenings and subsurface nanoglistenings are fluid-related phenomena developing mainly in hydrophobic acrylic IOLs and are associated with aqueous influx into the IOL matrix. Calcification presents in hydrophilic acrylic or silicone IOLs as deposits of hydroxyapatite or other phases of calcium. Snowflake degeneration is less common, and it manifests in older polymethyl methacrylate IOLs. DATA SOURCES.­: PubMed and ScienceDirect databases were searched for the following keywords: intraocular lens, IOL, cataract surgery, phacoemulsification, opacification, glistening, subsurface nanoglistenings, calcification, snowflake degeneration. English-language articles published up to October 15, 2019 were included in the study. The manuscript contains mainly a literature review; however, it was supplemented with original investigations from the David J. Apple International Laboratory for Ocular Pathology. CONCLUSIONS.­: Glistenings and subsurface nanoglistenings should be evaluated in a hydrated state and at room temperature; they manifest as microvacuoles sized from 1.0 to greater than 25.0 µm and less than 200 nm, respectively. Calcification deposits are situated on or underneath the surface of the IOL and can be stained with a 1% alizarin red solution or with the von Kossa method. Snowflake degeneration manifests as "particles" or "crystals," causing whitish IOL discoloration. Scanning electron microscopy or energy dispersive X-ray spectroscopy may improve the diagnostic accuracy.

Reversibility of the duet procedure: Bilateral exchange of a supplementary trifocal sulcus-fixated intraocular lens for correction of a postoperative refractive error.

PURPOSE: We present the case of a 49-year old female who underwent bilateral exchange of a supplementary trifocal sulcus-fixated intraocular lens (IOL) to correct a residual refractive error. Six months beforehand, she had been treated for hyperopia, astigmatism and presbyopia with a duet procedure to create reversible trifocality. OBSERVATIONS: Refractive lens exchange with combined implantation of a monofocal toric IOL into the capsular bag and a trifocal supplementary IOL into the ciliary sulcus (duet procedure) had been performed in both eyes. Decreased uncorrected distance visual acuity due to the refractive outcome of -0.75 diopter sphere (DS)/-0.25 diopter cylinder (DC)x10° for the right eye and -1.0DS for the left eye as well as the perception of photic phenomena were inacceptable for the patient. In the second operations, we exchanged the supplementary IOLs to correct the residual refractive error and achieve the target refraction of emmetropia. UDVA increased from 0.50 logMAR in both eyes prior to the IOL exchange to -0.22 logMAR in the right eye and -0.20 logMAR in the left eye. Binocular uncorrected near and intermediate visual acuity were -0.10 logMAR and 0.00 logMAR respectively after exchanging the sulcus-fixated supplementary IOLs, allowing for complete spectacle independence. CONCLUSIONS: This case demonstrates one of the most important benefits of the duet procedure: the possibility, if necessary, to easily remove or exchange the supplementary IOL from the ciliary sulcus. The duet procedure offers a safe treatment option in the event of postoperative complications like residual refractive error or intolerance to a multifocal optic.

Dispersive viscosurgical devices demonstrate greater efficacy in protecting corneal endothelium in vitro.

OBJECTIVE: During phacoemulsification, the corneal endothelium is protected by an ophthalmic viscosurgical device (OVD). In this in vitro study, we assessed six different OVDs for their effectiveness in protecting the corneal endothelium. METHODS AND ANALYSIS: Phacoemulsification was performed in cadaver eyes of young pigs. Five syringe units of six different OVDs were tested (Healon EndoCoat, Viscoat, Methylvisc, Healon, Healon GV, ProVisc). After surgery, the area of endothelium coated with OVD was determined in relation to the total endothelial surface. Additionally, an endothelial cell count was obtained. As a control, an endothelial cell count was obtained from freshly trephined corneas. Statistical analysis was performed using the Mann-Whitney U test and the Spearman correlation. RESULTS: The least postoperative endothelial coating and cell count were observed in the cohesive OVDs while the dispersive OVDs showed statistically significant higher values. Healon EndoCoat and Viscoat yielded a coating area of 86 (85-92)% and 85 (85-90)%, respectively. Endothelial cell count was highest in the two dispersive groups with 4065 (3928-4088) cells/mm2 (Methylvisc) and 4032 (4015-4115) cells/mm2 (Viscoat). Endothelial coating area and endothelial cell count correlated statistically significantly. CONCLUSION: Dispersive OVDs from this study showed greater adherence to the endothelial surface than the cohesive ones. Furthermore, postoperative endothelial cell counts of corneas treated with dispersive OVDs were higher than of corneas treated with cohesive OVDs. Our in vitro results suggest that dispersive OVDs protect the corneal endothelium better during phacoemulsification than cohesive OVDs.

[In Vitro Evaluation of the Optical Quality of Segmental Refractive Multifocal Intraocular Lenses]. / In-vitro-Untersuchung zur optischen Qualität segmental refraktiver multifokaler Intraokularlinsen.

OBJECTIVES: In customised patient care, it is important to know the optical quality of different intraocular lenses (IOL). In this study, the optical quality of three segmental intraocular lenses were compared. MATERIALS AND METHODS: The LENTIS Comfort LS-313 MF15, LENTIS Mplus X LS-313 MF30 and LENTIS High Add IOL LS-313 MF80 (Oculentis, Berlin, Germany) with a far power of + 21 D were analysed at the optical bench OptiSpheric IOL PRO (Trioptics GmbH, Wedel, Germany). The lenses have almost the same optical design but differ in the power of the near segment. The MF15 has a + 1.5 D addition to improve vision in intermediate distances, the MF30 has a near addition of + 3 D and the MF80 has a near addition of + 8 D. The modulation transfer function area (MTFa) and the Strehl ratio were examined for apertures of 3 mm (photopic) and 4.5 mm (mesopic). RESULTS: The MTFa values for the far focus are 33.34/30.80/51.53 (MF15/MF30/MF80) with an aperture of 3 mm and 25.38/22.52/43.15 for 4.5 mm. The MTFa values for the intermediate focus are 29.85/16.21/6.25 for a 3 mm aperture and 23.92/8.05/3.08 for 4.5 mm. The MTFa values for the near focus are 9.75/21.49/33.12 for an aperture of 3 mm and 4.95/22.70/31.68 for 4.5 mm. The Strehl ratio of the far focus is 0.34/0.30/0.52 for an aperture of 3 mm and 0.24/0.22/0.43 for 4.5 mm. For the intermediate focus, the Strehl ratio is 0.30/0.17/0.07 for an aperture of 3 mm and 0.24/0.08/0.03 for 4.5 mm. The Strehl ratio of the near focus is 0.10/0.22/0.33 for an aperture of 3 mm and 0.05/0.23/0.32 for 4.5 mm. CONCLUSION: We confirmed that the addition influences the optical quality of segmental bifocal intraocular lenses. For the far focus, the results of the MF15 and MF30 are similar. In intermediate distances, the MF15 achieves the best results. For near distances, the MF30 achieves better optical values than the MF15. The lens MF80, which has been designed for patients with maculopathies, achieves good results for far and near distances.

Does surgical treatment within 4 hours after trauma have an influence on neurological remission in patients with acute spinal cord injury?

BACKGROUND: The proper timing for surgery in patients with acute spinal cord injury is controversial. This study was conducted to detect if there is an advantage in early (within the first 4 hours after trauma) compared to late (between 4 and 24 hours after trauma) surgery on neurological outcome. METHODS: In this single institution prospective cohort study, data were analyzed from 51 spinal cord injured patients with an average age of 43.4 (±19.2) years. The influence of early (29 patients within the first 4 hours) as opposed to late (22 patients between 4 and 24 hours) decompression was evaluated by comparing data for neurological outcome. Patients of the study collectively suffered acute spinal fractures from C2 to L3 (cervical 39.2%, thoracic 29.4%, and lumbal 21.6%) or nonosseous lesions (9.8%). American Spinal Injury Association (ASIA) Impairment Scale (AIS) grades were assessed at time of admission and 6 months after trauma or longer depending on the time of release. Surgical treatment included early stabilization and decompression within 24 hours. RESULTS: No significant difference between improved neurological function, measured with the AIS, and an early or late surgery time can be seen (P=0.402). Furthermore, binary logistic regression shows no significant difference between sex or age, and AIS improvement as possible confounders. CONCLUSION: In our study, all patients with spinal cord injury were treated with spine stabilization and decompression within the first 24 hours after trauma. Surgical decompression within the first 4 hours after trauma was not associated with improved neurological outcome compared to treatment between 4 and 24 hours. In a clinical context, this indicates that there is a time frame of at least 1 day in which optimal care is possible.

Low intensity pulsed ultrasound in the treatment of long bone nonunions: Evaluation of cytokine expression as a tool for objectifying nonunion therapy.

BACKGROUND: Nonunion is one of the most common complications in bone healing. After several clinical studies, the effect of low intensity pulsed ultrasound (LIPUS) in the treatment of nonunions remains unclear because of the difficulty in evaluating its effect on bone healing. In former studies, the analysis of serum cytokine expression patterns over time has proven to be an objective method for showing the bone healing process and evaluating nonunion therapies. This study evaluates LIPUS as a treatment option for patients with nonunions based on the analysis of serum cytokine expression. METHODS: In this prospective, single institution study, venous blood samples from 23 patients were taken from October 2012 to October 2013 before starting LIPUS therapy and at the end of week 1 and 2 and after 1, 2, and 3 months. Patients attended clinical and radiological follow-up examinations at the same intervals. After treating all patients according to the LIPUS therapy protocol, we divided them into two groups: Group 1 consisted of patients with healing at the nonunion site, and Group 2 consisted of patients with failed nonunion therapy. We measured transforming growth factor-ß1 (TGF-ß1), platelet-derived growth factor (PDGF), and basic fibroblastic growth factor (bFGF) at all time-points. RESULTS: The TGF-ß1 serum concentration increased from the pre-treatment value to 1 week within the unsuccessful group. Otherwise, no significant differences between groups in measured cytokines during LIPUS therapy could be detected. CONCLUSION: Our findings suggest that LIPUS does not lead to a significant increase in cytokine levels in patients with nonunions. It is likely that "successful" treatment can be attributed to spontaneous healing. Our results suggest that LIPUS is not a proper treatment for long bone nonunions.

Failed treatment of long bone nonunions with low intensity pulsed ultrasound.

INTRODUCTION: The use of low intensity pulsed ultrasound (LIPUS) in the treatment of nonunions is still controversial. The present study is concerned with whether this procedure has a clinical use and which cofactors influence its therapeutic results. METHODS: In this prospective, single institution, observational study, data from October 2010 to October 2013 from 61 nonunions in 60 patients treated with EXOGEN(®) LIPUS therapy were analysed. The average age was 45.4 ± 9.81 (18-63) years. Treatment was primarily done on long bones of the lower extremity (75.4 %). All 61 nonunions were examined after treatment, and the rate of healing as well as functional and subjective results were evaluated. Based on clinical and radiological findings, patients were divided into two groups: G1-successful treatment; and G2-unsuccessful treatment. Groups were compared to one another to identify possible factors influencing treatment. RESULTS: Twenty (32.8 %) patients showed bone consolidation with an average time of healing of 5.3 (2-7) months. In patients without successful treatment, who underwent revision surgery instead, full weight bearing took on average 3.7 months longer, and they were able to return to work 6.8 months later. Most of the treated patients (70.5 %) reported no improvement in pain. In G2, 12 (29.3 %) patients suffered in their previous history from osteitis; in G1 there were only two patients (10 %) (p = 0.012). There were further significant differences in the age of the fracture, the type of osteosynthesis, the gap size, as well as the NUSS score. CONCLUSION: Despite patients being chosen strictly according to EXOGEN(®) indications, only a small number of patients with nonunions who underwent LIPUS therapy experienced successful treatment (32.8 %). Overall, its use resulted in a clear delay in the time of treatment, so that according to our results, the use of LIPUS should be seen critically in long bone nonunions and use should be made on a case-by-case basis.