Search

Robert Edward T Ang,1 Pedro Tañá-Rivero,2 Francisco Pastor-Pascual,3 Pavel Stodulka,4 Manfred Tetz,5 Isaak Fischinger6 1Cataract and Refractive Surgery Department, Asian Eye Institute, Makati City, Philippines; 2Cataract and Refractive Surgery Department, Oftalvist, Alicante, Spain; 3Cataract and Refractive Surgery Department, Oftalvist, Valencia, Spain; 4Cataract and Refractive Surgery Department, Gemini Eye Clinic, Zlin, Czech Republic; 5Cataract and Refractive Surgery Department, Augentagesklinik Spreebogen, Berlin, Germany; 6Medical Faculty, Johannes Kepler University Linz, Linz, AustriaCorrespondence: Robert Edward T Ang, Asian Eye Institute, 8th Floor PHINMA Plaza, Rockwell Center, Makati City, Philippines, Email angbobby@hotmail.comPurpose: To show the visual and refractive outcomes in cataract patients with corneal astigmatism when bilaterally implanted with a biconvex aspheric toric monofocal intraocular lens (IOL) with a double C-loop haptic-design.Methods: Forty-seven cataract patients (94 eyes) with corneal astigmatism (≥ 0.75D) were implanted with the monofocal PODEYE toric IOL and assessed for 4– 6 months post-surgery. Measurements included monocular and binocular uncorrected-distance visual acuity (UDVA) and corrected-distance visual acuity (CDVA), under both photopic and mesopic lighting conditions. Refraction, photopic and mesopic contrast sensitivity (with and without glare), and rotational stability were also recorded at the last postoperative visit.Results: At 4– 6 months, 78.2% and 98.9% of eyes were within ± 0.50D and ± 1.00D of the target refraction, respectively. The mean spherical equivalent and refractive cylinder values were 0.09± 0.35D and − 0.36± 0.35D, respectively. 76.5% and 98.8% of eyes presented a postoperative refractive cylinder of ≤ 0.50D and ≤ 1.00D, respectively. 91.5% and 100% of patients had a binocular UDVA and CDVA of ≥ 20/25, respectively. The mean binocular UDVA and CDVA were 0.02± 0.08 and − 0.02± 0.07 logMAR, respectively. Under mesopic conditions, 78.7% and 83.0% of patients presented a binocular UDVA and CDVA ≥ 20/32, respectively. The mean binocular UDVA and CDVA were 0.15± 0.11 and 0.12± 0.11 logMAR, respectively. The patients showed good contrast sensitivity under photopic and mesopic conditions. The mean absolute IOL rotation was 1.22± 2.21 degrees with 97.87% of eyes having a rotation of < 10 degrees.Conclusion: This study shows good visual and refractive outcomes for the PODEYE toric IOL when implanted bilaterally in cataract patients with corneal astigmatism.Keywords: monofocal toric, astigmatism, double C-loop, intraocular lens, cataract

Purpose: To determine (1) if measurements of surgically induced astigmatism (SIA) as measured by keratometry (K) and total keratometry (TK) differ (2) if SIA affects the magnitude and/or meridian of keratometric astigmatism (3) if SIA evolves over time., Setting: Tertiary care center., Design: Retrospective data analysis., Methods: A swept-source optical coherence tomography biometry dataset (IOLMaster700) consisting of 498 eyes (327 patients) from a tertiary care center was analyzed. For all eyes preoperative and postoperative biometric measurements at 1-month, 3-month, and 6-months postoperative visits were considered for vector analysis of SIA K and SIA TK ., Results: Centroids in right and left eyes were 0.26 diopters (D) @5 degrees/0.31 D @1 degree for SIA K and 0.27 D @4 degrees/0.34 D @1 degree for SIA TK . Centroids for difference vectors K-TK in right and left eyes were 0.02 D @ 176 degrees/0.03 D @6 degrees. The mean SIA magnitudes in right and left eyes were 0.48 ± 0.41 D and 0.50 ± 0.37 D for SIA K and 0.53 ± 0.42 D and 0.54 ± 0.40 D for SIA TK . In eyes with ATR astigmatism, an increase in postoperative astigmatism magnitude was more common than a decrease. More than 30% of eyes showed changes in the meridian of more than 15 degrees., Conclusions: Overall, we observed differences in K- and TK-derived SIA, and changes in SIA magnitude over time. For postsurgical interventions, postoperative astigmatism meridian values should be measured to base treatments. Astigmatism magnitude showed a tendency to decrease for steep-meridian incisions and to increase in flat-meridian incisions., (Copyright © 2023 Published by Wolters Kluwer on behalf of ASCRS and ESCRS.)

Purpose: To evaluate corneal stiffening of porcine corneas induced by corneal crosslinking (CXL) with constant irradiance as a function of total fluence., Methods: Ninety corneas from freshly enucleated porcine eyes were divided into five groups of 18 eyes. Groups 1-4 underwent epi-off CXL using a dextran-based riboflavin solution and an irradiance of 18 mW/cm 2 , group 5 served as the control group. Groups 1 to 4 were treated with a total fluence of 20, 15, 10.8, and 5.4 J/cm 2 , respectively. Thereafter, biomechanical measurements were performed on 5 mm wide and 6 mm long strips using an uniaxial material tester. Pachymetry measurements were performed on each cornea., Results: At 10% strain, the stress was 76, 56, 52, and 31% higher in groups 1-4, respectively compared to the control group. The Young's modulus was 2.85 MPa for group 1, 2.53 MPa for group 2, 2.46 MPa for group 3, 2.12 MPa for group 4, and 1.62 MPa for the control group. The difference between groups 1 to 4 and the control group 5 were statistically significant ( p  = <0.001; p  = <0.001; p  = <0.001; p  = 0.021). In addition, group 1 showed significantly more stiffening than group 4 ( p  = <0.001), no other significant differences were found. Pachymetry measurements revealed no statistically significant differences among the five groups., Conclusion: Additional mechanical stiffening can be achieved by increasing the fluence of the CXL. There was no threshold detected up to 20 J/cm 2 . A higher fluence could compensate the weaker effect of accelerated or epi-on CXL procedures.

Purpose: Corneal Crosslinking (CXL) strengthens the keratoconus cornea and prevents further disease progression. Modified crosslinking protocols and different riboflavin solutions have been proposed to optimize the procedure and improve treatment success., Methods: PubMed research of relevant publications and report of own experiences with different CXL protocols., Results: Accelerated CXL shows comparable efficiency with shorter surgery time and similar complication rates. Customized CXL provides improved results with faster epithelial healing. CXL in a hyperoxic environment seems to be a safe and effective transepithelial alternative with presumably less complications and fewer side effects. Thin corneas (<400 µm) can be treated safely by corneal swelling using hypoosmolar riboflavin solutions and reducing the applied UV-energy. The combination of CXL with photorefractive keratectomy (PRK) can be considered in patients with contact lens intolerance improving visual acuity, however, with increased risk of visual loss compared to CXL alone. Two-Photon (2Ph) CXL is a promising new technology enabling three-dimensional CXL., Discussion: Recently developed CXL protocols offer advantages over the standard "Dresden-protocol" and should be considered in patients with progressive keratectasia.

Introduction: To report a late onset, deep stromal and endothelial corneal scar in a keratoconus patient after corneal collagen cross-linking (CXL)., Case Description: Observational case report. A 29-year-old man with bilateral keratoconus received an accelerated (A-CXL 10*9) epithelium-off CXL procedure in the left eye.6-months postoperatively, a 2.2 × 1.2 mm inferocentral corneal scar was detected, which was located in the posterior stroma ranging from approximately 350 µm until the endothelium, therefore was situated below the demarcation line. A topical corticosteroid treatment did not influence the magnitude or configuration of the scar. Visual acuity was never affected, which includes the examination 12 months postoperatively., Conclusions: We report a case of a late onset deep stromal and endothelial corneal scar 6 months after accelerated CXL as postoperative complication without affecting visual acuity.

Purpose: The purpose of the study was to evaluate the potential accuracy of different second eye refinement methods in a patient cohort with short axial eye length to assess the performance of intraocular lens (IOL) power calculation schemes in high hyperopes., Methods: The study design was a single-center, single-surgeon retrospective consecutive case series. The setting of the study was in Augen- und Laserklinik, Castrop-Rauxel, Germany. Patients were assessed after uneventful bilateral cataract surgery implanting either spherical (SA60AT) or aspheric (ZCB00) IOLs. Inclusion criteria were an axial eye length of ≤21.5 mm and/or emmetropizing IOL power of >28.5 dpt. Outcome measures were the mean absolute prediction error (MAE), median absolute prediction error, mean prediction error with standard deviation, median prediction error, and the percentage of eyes with an absolute prediction error (absPE) within 0.25 dpt, 0.5 dpt, 0.75 dpt, or 1.0 dpt. Second eye refinement was performed using the first eye prediction error, either with a correction coefficient of 0.50 (SER1), or an individual coefficient optimized for MAE., Results: A total of 55 patients were assessed. A statistically significant reduction in the absPE after the application of SER1 was observed in 9 of 13 formulae. The SER1 refined Hoffer Q, refined Holladay I, refined Holladay II, refined Kane, refined Okulix, and refined PEARL-DGS provided a smaller absPE than other methods., Conclusion: In this patient cohort with a short axial eye length, the second eye refinement led to a lower MAE in almost all formulae. The use of refinement in Kane, Okulix, PEARL-DGS, and Castrop formulae exhibited the lowest MAE.

Purpose : To evaluate rotational stability, tilt and decentration of a new monofocal IOL with a 7.0 mm optic and frame haptics. Methods: Prospective post-market clinical follow-up study at the Kepler University Hospital Linz, Austria. An Aspira-aXA (HumanOptics, Germany) was implanted in 74 eyes of 42 cataract patients. The lens was manufactured with toric markings. IOL rotational stability was evaluated by comparing its position at the end of surgery (EoS) versus 1 day, 1 week, 1 month and 4 months postoperatively. IOL tilt and decentration were measured using a Scheimpflug camera at 1 week, 1 month and 4 months. Results: Median absolute IOL rotation was 1.42 degrees (n = 52; mean = 2.18 ± 2.23°) within 1 day after surgery and was significantly higher compared to all later intervals (median <1.0 degree; P = .001). At the 4 months follow-up, IOL rotation was within 5.0 degrees in 85% of the eyes (n = 40) and within 10.0 degrees in 98% (n = 46) of the eyes. The only eye with an IOL rotation of ≥ 10.ty0 degrees (EoS vs . 1 day) had an AL of 26.45 mm. At the last follow-up, the IOL vertical and horizontal tilt referenced to the pupillary axis was in average less than 1.5 degrees in both eyes (n = 54; maximum 5.85°). Decentration in both meridians was on average less than 0.10 mm in both eyes (maximum 0.30 mm). Conclusion: The one-piece Aspira-aXA IOL showed good and stable positioning within the capsular bag over a 4 months period.

Purpose: To evaluate corneal stiffening in porcine eyes induced by corneal cross-linking (CXL) using riboflavin dissolved in either aqueous dextran or hydroxypropyl methylcellulose (HPMC) solution., Methods: Fifty-one porcine corneas were divided into three groups of 17 each. After deepithelialization, the first (Dresden) group was treated for 30 minutes with 0.1% riboflavin (riboflavin-5-monophosphate in 0.9% NaCl) dissolved in hypertonic 20% dextran and the second (HPMC) group for 30 minutes with isotonic solution containing 0.1% riboflavin and 1.1% HPMC. Thereafter, corneas of both groups were irradiated using 5.4 J/cm 2 (irradiance of 9 mW/cm 2 for 10 minutes; 10*9). After CXL, all corneas were kept in an isotonic 16% dextran bath for 2 hours to obtain an equal hydration state. The third group served as the control group. Stress-strain measurements were performed on 5-mm-wide strips. Corneal thickness was monitored throughout the entire course of the experiments., Results: The required stress for a 10% strain was increased by 83% in the Dresden group and 35% in the HPMC group compared to the control group. Resultant Young's modulus (at 10% strain) was 2.53 ± 0.73, 1.87 ± 0.50, and 1.47 ± 0.44 Pa for the Dresden, HPMC, and control groups, respectively. The differences between the Dresden and HPMC groups ( P = .006), the Dresden and control groups ( P < .001), and the HPMC and control groups ( P = .014) were statistically significant. Pachymetry measurements showed a significantly increased corneal thickness after application of HPMC compared with the Dresden group ( P = .002) and control group ( P = .041)., Conclusions: The biomechanical stiffening of the cornea by CXL can be achieved using dextran- and HPMC-based riboflavin solutions in porcine corneas with an application time of 30 minutes. Dextran-based riboflavin solutions seem to induce a slightly stronger biomechanical response in this setting. HPMC solutions induce less thinning than dextran solutions. [ J Refract Surg . 2021;37(9):631-635.] .

More than 60% of the 1,700 infectious diseases that affect human come from animals and zoonotic pandemics, after starting from sporadic phenomena limited to rural areas, have become a global emergency. The repeated and frequent zoonotic outbreaks such as the most recent COVID-19 pandemic can be attributed also to human activities. In particular, the creation of enormous intensive domestic animal farms, the indiscriminate use of antibiotics, the destruction of forests, the consumption of the meat of wild animals and the illegal animal trade are all factors causing the insurgence and the transmission of zoonotic diseases from animals to humans. The purpose of this study was to explore the knowledge of the One Health concept including the zoonotic risk potentially derived from illegally traded pet animals and wildlife among adolescents in 6 different countries (Italy, Austria, Slovenia, Germany, Mauritius, and Japan). A representative sample of 656 students was recruited and all participants took an anonymous questionnaire. Data were analyzed by ANOVAs to estimate the prevalence of correct health prevention behaviors and to identify the influential factors for these behaviors. After two theoretical-practical lectures, the same anonymous questionnaire was administered for the second time in order to assess the efficacy of the program. The proportion of students who did not know that many diseases affecting humans come from animals is 28.96% while 32.16% of them did not know what a zoonosis is. The circularity of the One Health concept related to the transmission of diseases from animals to humans and vice-versa is not understood from a large prevalence of the adolescents with 31.40 and 59.91% of wrong responses, respectively. Furthermore, rabies is not considered as a dangerous disease by 23.02% of the adolescents. After two theoretical-practical classroom sessions, the correct answers improved to 21.92% according to the different question. More than a third of the student cohort investigated showed a profound ignorance of the zoonotic risks and a poor understanding of the One Health concept. The authors believe that the teaching of health prevention with a One Health approach and a practical training should be included in every school curriculum., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Zucca, Rossmann, Dodic, Ramma, Matsushima, Seet, Holtze, Bremini, Fischinger, Morosetti, Sitzia, Furlani, Greco, Meddi, Zambotto, Meo, Pulcini, Palei and Zamaro.)

Illegal animal trade (pet, wildlife, animal products, etc.) is an example of transnational organized crime (T.O.C.) that generates a large business with huge profit margins. This criminal activity causes several negative effects on human health (zoonoses), animal health and welfare, market protection, consumer fraud and may be used as tool of agro/bio-terrorism. Illegal animal trade can facilitate the spread of zoonoses that are defined as diseases and infections that are transmitted by vertebrate animals to man. Humans are affected by more than 1,700 known pathogens: 60% of existing human infectious diseases are zoonotic and at least 75% of emerging infectious diseases of humans have an animal origin and 72% of zoonoses originate from wildlife or exotic animals. The Bio-Crime Project was developed in 2017 by Friuli Venezia Giulia Region (Italy) and Land Carinthia (Austria) together with other public institutions to combat illegal animal trade and to reduce the risk of disease transmission from animals to humans. Project partners agreed that a multi-agency approach was required to tackle the illegal animal trade that was high value, easy to undertake and transnational crime. The Bio-crime model of cross-border cooperation introduces the novel approach of replicating the cooperative framework given by the triad of Veterinary Public Health, Justice and Law Enforcements/Customs across borders using the International Police and Custom Cooperation Centres (IPCCCs) as a connection link among public entities of the neighbor countries. This model has been recognized as a best practice at European level because it can be easily replicated and scaled up without any supplementary cost for Member States., (Copyright © 2020 Zucca, Rossmann, Osorio, Karem, De Benedictis, Haißl, De Franceschi, Calligaris, Kohlweiß, Meddi, Gabrutsch, Mairitsch, Greco, Furlani, Maggio, Tolomei, Bremini, Fischinger, Zambotto, Wagner, Millard, Palei and Zamaro.)

Purpose: To assess endothelial safety and efficacy of ex vivo corneal collagen cross-linking (CXL) in human corneal transplants stored in 2 different culture media., Design: Fellow-eye controlled laboratory study of ex vivo human donor corneas., Methods: Three sets of paired human donor corneas, 5 pairs each, were stored in organ culture medium before deswelling either at 31 C or at room temperature. One eye of each pair was cross-linked by 0.1% riboflavin in hydroxylpropyl methylcellulose (HPMC) instillation for 10 minutes followed by 10 minutes of ultraviolet-A (9 mW/cm 2 ) irradiation while contralateral eyes served as controls. In Set 1, endothelial cell densities were determined. In Set 2, paired samples were assigned to the 2 deswelling media and CXL efficacy was assessed comparing to untreated controls using collagenase-A-assisted enzymatic digestion. In Set 3, biomechanical testing was performed in the eye pairs (treated vs control) by stress/strain measurements., Results: There was no difference in endothelial cell counts between CXL samples and controls (P = .21). No statistically significant difference in digestion dynamics was found between tissues stored in the 2 different culture media. Complete enzymatic digestion was slowed down by 3 hours in the cross-linked samples (P = .036). Stress needed for a 12% strain was increased by 34% in the treatment group compared to control (P = .04)., Conclusions: Ex vivo CXL of human donor tissue is an effective and safe procedure with no difference regarding efficacy between 2 commercially available deswelling media. Biochemical and biomechanical resistance were significantly increased after CXL. Patients requiring keratoplasty owing to corneal melting might benefit from the strengthening effect of preoperative CXL of donor tissue., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Purpose: To study the intraocular pressure (IOP) variation during vacuum and docking of femtosecond laser application., Setting: Department for Ophthalmology, Kepler University Hospital, Johannes Kepler University Linz, Austria., Design: Experimental study., Methods: Intracameral intraocular pressure (IOP) was monitored in 30 porcine ex vivo models using a dual femtosecond laser platform (VICTUS). Five different baseline IOP levels (10 to 30 mm Hg) were assessed during fluid-filled (liquid) docking, full-contact (applanating) docking, and vacuum application without docking., Results: Raising the baseline intracameral IOP from 10 to 30 mm Hg increased the IOP from 27.55 mm Hg ± 5.93 (SD) to 56.85 ± 6.10 mm Hg in the fluid-filled docking group, and from 60.91 ± 8.41 mm Hg to 90.11 ± 6.64 mm Hg in the full-contact docking group. The full-contact docking procedure per se (excluding vacuum effect) increased the IOP by 61.7% (+36.58 ± 5.84 mm Hg). In contrast, fluid-filled docking (excluding vacuum effect) raised the IOP by only 3.1% (+0.72 ± 2.71 mm Hg). Each 5 mm Hg reduction of baseline IOP resulted in a mean IOP reduction of 7.33 ± 3.05 mm Hg in the fluid-filled group, and 7.30 ± 6.88 mm Hg in the full-contact docking group (P < .001). Decreasing baseline intracameral IOP from 15 to 10 mm Hg resulted in the highest IOP reduction between all subgroups (P < .01)., Conclusions: Baseline IOP, docking procedures, and vacuum influenced IOP during femtosecond laser application in a synergistic manner. Lowering the baseline intracameral IOP resulted in a significantly lower IOP during fluid-filled docking for cataract surgery and full-contact docking for refractive surgery. Full-contact (applanating) docking resulted in a significantly higher IOP elevation compared with similar IOP values found during fluid-filled (liquid) docking and the application of the suction ring alone without docking., (Copyright © 2019 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.)

Purpose: To investigate safety of accelerated corneal crosslinking during the first postoperative month., Methods: In this retrospective study, 76 eyes of 60 patients with verified progressive keratectasia were enrolled in this study and followed for 1 month after accelerated CXL (18 mW/cm 2 for 5 min, radiant exposure 5.4 J/cm 2 ) (A-CXL(5*18)). Preoperatively, objective refraction, slit lamp inspection, and corneal tomography were performed. Early postoperative slit lamp examinations were performed on days 1 and 4. At 1 month, objective refraction, slit lamp inspection, and corneal tomography were performed., Results: Gender distribution was m:f = 55:21, OD:OS was 40:36, and the average age was 26.5 ± 8.6 years at surgery. Only 71 of the 76 eyes completed the 1-month follow-up, indicating a dropout rate of 6.6%. In 7.0% (n = 5), sterile infiltrates were observed; 5.6% of eyes (n = 4) showed delayed epithelial healing (> 4 days) in 2.8% (n = 2); an infection occurred and in 1 eye (1.4%), a stromal scar was detected; no other complications, neither a loss of two or more Snellen lines at 1 month postoperatively, were observed. As a risk factor for sterile infiltrates, thin preoperative pachymetry could be identified (p = 0.027)., Conclusions: This study revealed no difference in early postoperative safety between CXL using 18 mW/cm 2 and standard corneal CXL. Thinner preoperative pachymetry could be identified predicting a higher rate of postoperative sterile infiltrates.

Background: Intravitreal anti-VEGF therapy is the gold standard in the treatment of neovascular age-related macular degeneration (nAMD). In recent literature, the benefit of additional photodynamic therapy (PDT) has been debated. The aim of our study was to compare the functional and structural effects of long-term combination therapy with PDT plus ranibizumab with monotherapy with ranibizumab. Material and Methods: In a retrospective study, patients suffering from nAMD were followed up for at least 42 months. Patients were assigned to group A (monotherapy with ranibizumab according to pro re nata [PRN]) or group B (combination therapy with one-time PDT plus ranibizumab according to PRN). The best-corrected visual acuity (BVCA) was evaluated at the starting and end points, together with central retinal thickness (CRT), maximal retinal thickness (MRT) and the maximal diameter of the base of the subretinal plaque in spectral-domain optical coherence tomography (SD-OCT), at the first measurement and at the end point. Results: Group A consisted of 21 eyes (17 patients) and group B consisted of 12 eyes (11 patients). The average follow-up from starting to end point was 64 months and 47 months, from the first measurement of SD-OCT to the end point. Within this period, patients in group A received 19 ± 14 intravitreal injections, and patients in group B received 22 ± 10 intravitreal injections. BCVA at the starting point was 0.31 ± 0.26 in group A and 0.31 ± 0.17 in group B. At the end point, BCVA in group A was 0.29 ± 0.25 (p = 0.405), and in group B 0.25 ± 0.20 (p = 0.142). CRT decreased in group A by 72 ± 178 µm (p = 0.024) and group B by 28 ± 98 (p = 0.1335). MRT decreased in group A by 25 ± 135 µm (p = 0.166) and in group B by 2 ± 118 µm (p = 0.421). The base of the subretinal plaque increased in group A by 32 ± 1468 µm (p = 0.242) and in group B by 748 ± 1024 (p = 0.025). Conclusion: In a long-term follow-up of 5.3 years, patients with nAMD in both groups exhibited good stabilisation of visual acuity. In both groups, retinal thickness decreased and the base of the subretinal plaque increased. With respect to SD-OCT morphological criteria, patients in group A (monotherapy) responded slightly better to therapy than patients in group B (combination group)., Competing Interests: Interessenkonflikt: Nein., (Georg Thieme Verlag KG Stuttgart · New York.)

Purpose: To determine the riboflavin concentration gradient in the anterior corneal stroma when using hydroxypropyl methylcellulose (HPMC) or dextran as the carrier agent., Methods: Four different groups of porcine corneas (5 each) were compared regarding the riboflavin concentration in the anterior stroma. Prior to all experiments, stable hydration conditions were established for the corresponding solution. The dextran groups were treated with 0.1% riboflavin in 20% dextran for 10 and 30 minutes and the HPMC groups with 0.1% riboflavin in 1.1% HPMC for 10 and 30 minutes. After imbibition, nonlinear microscopy and consecutive image analysis were used to determine two-photon fluorescence intensities. To determine the riboflavin concentration, corneas were saturated and measured a second time by two-photon microscopy. With this measurement, a proper correction for absorption and scattering could be performed. Ultraviolet-A (UVA) transmission was measured after the application time for each group., Results: Riboflavin concentration decreased with increasing depth and increased with longer application times in all groups. Comparing the dextran for 30 minutes and HPMC for 10 minutes groups, a significantly higher stromal riboflavin concentration was found within the most anterior 70 µm in the dextran group for 30 minutes, whereas deeper than 260 µm HPMC-assisted imbibition for 10 minutes yielded higher concentrations. In dextran-treated corneas, values obtained from pachymetry were substantially reduced, whereas HPMC-assisted imbibition led to a decent swelling. UVA transmission values were higher in dextran-assisted imbibition than in HPMC-assisted imbibition., Conclusions: Stromal riboflavin gradients are similar when applied in dextran for 30 minutes and HPMC for 10 minutes. When using HPMC solutions, a shallower cross-linked volume is expected due to a higher corneal hydration. [J Refract Surg. 2016;32(12):798-802.]., (Copyright 2016, SLACK Incorporated.)

Purpose: To compare the efficacy of customized corneal cross-linking (CXL) with standard CXL., Design: Prospective, nonrandomized comparative clinical study., Methods: In a prospective study at the Institut für Refraktive und Ophthalmo-Chirurgie (IROC), Zurich, Switzerland, 40 eyes of 40 patients with documented progressive primary keratoconus were treated with customized CXL (n = 20) or standard CXL (n = 20) and followed for 1 year. Customized irradiation patterns had an energy fluence of 9 mW/cm(2) and total energy levels ranging from 5.4 J/cm(2) up to 10 J/cm(2) and were centered on the maximum of the posterior float. The control group received homogenous irradiation with a fluence of 9 mW/cm(2) and a total energy of 5.4 J/cm(2). Scheimpflug tomographies, endothelium cell count, best spectacle-corrected visual acuity (BSCVA), and anterior segment optical coherence tomography (OCT) were compared preoperatively and 1 year postoperatively., Results: Pachymetry and ΔKmax showed significant changes 1 year postoperatively within each group. Epithelial healing time, ΔKmax, and regularization index (RI) were significantly better in the customized CXL group. Two out of 19 eyes (11%) in the standard group but 7 out of 19 eyes (37%) in the customized CXL group showed a flattening of 2 or more diopters (P = .03). The RI was 5.2 ± 2.7 D in the customized group vs 4.1 ± 3.1 D in the control group (P = .03). Statistically significant correlations between RI and preoperative Kmax, preoperative pachymetry, and preoperative posterior float were found only in the customized group., Conclusions: Customized CXL seems to be as safe as standard CXL with stronger flattening in Kmax and RI, and a faster epithelial healing period., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Purpose: To report two cases with very late-onset scarring of the cornea after photorefractive keratectomy (PRK) induced by cataract surgery., Methods: Case report and literature review., Results: Two patients presented with a subepithelial corneal scar more than 20 years after PRK. Scarring occurred within the first few months after cataract surgery. Scar tissue was successfully removed by laser-assisted anterior lamellar keratoplasty., Conclusions: A few cases of late-onset corneal scarring after PRK have been described in the literature following trauma or ophthalmic surgery. Due to the need for cataract surgery in an aging population with previous PRK, this might become a more common problem., (Copyright 2016, SLACK Incorporated.)

Purpose: To determine the riboflavin concentration gradient in the anterior corneal stroma when using the Dresden protocol with different dextran solutions., Methods: Three different groups of porcine corneas, five each, were compared regarding the riboflavin concentration in the anterior stroma. Before all experiments, stable hydration conditions were established for the corresponding solution. All groups were treated with 0.1% riboflavin in different dextran solutions (15%, 16%, 20%). After imbibition, two-photon microscopy was used to determine fluorescence intensity. For signal attenuation and concentration determination corneas were saturated and measured a second time by two-photon microscopy. Additionally, the distribution was calculated mathematically and compared to the empiric results., Results: Riboflavin concentration is decreasing with depth for all dextran solutions. A nearly constant concentration could be determined over the first 75 μm. Analysis of the fit functions leads to diffusion coefficients of D = 2.97 × 10-7 cm2/s for the 15% dextran solution, D = 2.34 × 10-7 cm2/s for the 16% dextran solution, and D = 1.28 × 10-7 cm2/s for the 20% dextran solution. The riboflavin gradients of the 20% dextran group were statistically significantly different from 15% dextran starting at a depth of 220 μm and deeper (P = 0.047). The 16% dextran group differed statistically at a depth of 250 μm and deeper (P = 0.047). These results show a significant difference to those published previously., Conclusions: With correct settings two-photon microscopy is a precise way to determine the concentration of riboflavin in cornea. The measured gradient is excellently fit by a Gaussian distribution, which comes out as a solution of Fick's second law.

Purpose: To determine the safety of superficial corneal crosslinking after laser in situ keratomileusis (LASIK)., Setting: Institut für Refraktive und Ophthalmo-Chirurgie, Zurich, Switzerland., Design: Prospective study., Methods: Eyes with an ectasia risk score of 2 or higher were treated with standard LASIK (90 μm flap) for myopia correction, after which a rapid corneal crosslinking was performed in the interface (riboflavin 0.5% for 2 minutes, 9 mW/cm(2) for 5 minutes) (Group 1). The follow-up was up to 1 year. The prevalence of complications was statistically compared with that in a group of eyes matched regarding age, sex, and attempted refractive correction that were treated with standard LASIK only (Group 2)., Results: One month postoperatively, 5 eyes in Group 1 lost 1 line of corrected distance visual acuity (CDVA) compared with 1 eye in Group 2 (P < .05). One year postoperatively, all eyes regained their preoperative CDVA, indicating a complication rate of less than 5%. The refractive success was identical in both groups. Early postoperative complications such as erosions (16%), diffuse lamellar keratitis (DLK) stage 1 (38%), and DLK stage 2 (5%) were statistically significantly more frequent after superficial corneal crosslinking, leading to a statistically significantly reduced uncorrected distance visual acuity at 1 month (P < .001)., Conclusions: Based on 1-year results, superficial corneal crosslinking might be considered a safe adjunct to LASIK, with a delayed visual rehabilitation and a higher prevalence of transient side effects. It is not proved whether superficial corneal crosslinking can prevent iatrogenic keratectasia., Financial Disclosure: No author has a financial or proprietary interest in any material or method mentioned., (Copyright © 2015 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.)

Background: Pupil centroid shift (PCS) is an easily measured parameter which is rarely taken into consideration when planning surgery., Purpose: The aim of this study was to determine the physiological range of PCS and to evaluate its role in refractive and cataract surgery., Methods: The pupil center was measured in 103 eyes of 103 patients using the newest PCS module of the Allegro Topolyzer Vario (Version 1.76r58, Wavelight-Alcon, Erlangen, Germany) and the difference between a mesopic and a photopic environment was determined as PCSm. Additionally, these measurements were linearly extrapolated to pupil diameters of 2 mm and 7 mm (photopic-scotopic, PCSe). The statistical analysis included correlations between various demographic and topographic parameters and PCS., Results: The average (± standard deviation) PCSm was 0.12 ± 0.08 mm with a range of 0.02-0.53 mm, with 2 eyes out of 95 (2%) having a PCSm of more than 0.4 mm. The extrapolated PCSe was 0.24 ± 0.16 mm and ranged from 0.03 to 0.78 mm, with 14 eyes out of 95 (15%) having a PCSe of more than 0.4 mm. Of the 95 eyes 3 (3%) showed a PCSe of more than 0.7 mm. There was no correlation between PCS with any of the demographic parameters tested., Conclusion: Up to 15% of the patients showed a PCS of more than 0.4 mm which requires a decision of the (refractive) ophthalmic surgeon as to whether the optical zone should be centered on the photopic or mesopic/scotopic pupil center. In the 3% of patients with a PCSe value greater than 0.7 mm, the implantation of multifocal intraocular lens (IOL) is not recommended.

Purpose: To experimentally evaluate the efficacy of corneal crosslinking (CXL) by injecting the photomediator riboflavin into the corneal stroma via intrastromal channels., Methods: Five groups of pig corneas, nine each, were compared regarding stress-strain relationship and UV-absorption. Group 1 had intrastromal channels floated with riboflavin 0.5%-solution followed by UVA-irradiation (3 mW/cm(2) for 30 minutes); group 2 was handled like group 1, but were irradiated with 9 mW/cm(2) for 10 minutes; group 3 was treated according to the Dresden protocol (epi-off, 9 mW/cm(2) for 10 minutes); group 4 had the identical channel system, no riboflavin but identical irradiation; group 5 with native corneas served as a control group. The intrastromal channels were created with a femtosecond laser. The stress-strain relations were measured in corneal strips using a uniaxial material tester at strains up to 12%. The UV-transmission of the corneas was measured in groups 1, 3, and 5., Results: The stress needed for a 10% strain was significantly increased by 82% in the corneas treated with the Dresden protocol compared with native cornea (P = 0.0005). With intrastromal application of riboflavin the significant increase was 87% (P = 0.0005) in group 1 and 64% (P = 0.007) in group 2. The channel formation alone did not alter biomechanics (P = 0.923). The corneal UVA-transmission was 2.4% after intrastromal riboflavin application, 8.9% after the treatment according to the Dresden protocol, and 57.9% in native corneas., Conclusions: The experiments demonstrate the intrastromal application of riboflavin by means of intrastromal channels a feasible "epi-on" approach for CXL. More experimental data are needed before clinical testing., (Copyright 2014 The Association for Research in Vision and Ophthalmology, Inc.)

Background: More than 10 years after the clinical introduction of corneal cross-linking (CXL) the indications and contraindications are still not yet defined. Fundamental for such a list is the incidence of complications., Methods: A PubMed search for complications of corneal crosslinking published up to March 2013 was carried out., Results: The published complication rates ranged from 1 % to 10 % depending on the stage of keratoconus. Early postoperative complications were transient stromal haze, sterile infiltrates, endothelium decompensation, delayed epithelial healing and infectious keratitis. Stromal opacity can be a delayed postoperative event., Conclusions: Complications after corneal cross-linking treatment for keratoconus are rare but the management of these complications may need keratoplasty.