Comparison of two digital alignment systems for toric intraocular lens implantation.

PURPOSE: To compare the two most used digital alignment systems regarding precision, repeatability and loss of track. METHODS: 15 eyes of 15 patients older than 21 years with cataracts were included in this prospective study. The two systems were intraoperatively superimposed and recorded, and the alignment of the two displayed alignment axes was analysed regarding precision, repeatability and loss of track. RESULTS: There was a significant difference in precision and repeatability between the two digital alignment systems regarding the projected alignment axis. The deviation from the actual target axis was significantly different, with a mean of 0.34°±0.75° for the Zeiss system and 1.60°±1.08° for the Alcon system (p=0.03, n=14). The within-subject SD was significantly lower with 0.21° for the Zeiss system and 0.34° for the Alcon system (p=0.03, n=14). CONCLUSIONS: The Zeiss Callisto system showed a significantly lower deviation from the target axis, higher stability with eye movements and less need for microscope illumination than the Alcon system. Both systems showed high precision when compared with manual marking methods. TRIAL REGISTRATION NUMBER: NCT05220683.

Comparison of rebubbling rate between preloaded endothelium-in and preloaded no-touch endothelium-out Descemet membrane endothelial keratoplasty transplantation.

BACKGROUND: To compare the difference in rebubbling rates between patients undergoing Descemet membrane endothelial keratoplasty (DMEK) with endothelium-in using a standard IOL cartridge and those with endothelium-out DMEK utilizing a no-touch technique with borosilicate glass cartridge transplantation. METHODS: This retrospective study included all eyes that underwent preloaded endothelium-in or endothelium-out DMEK transplantation from June 2019 to December 2023 at the Hanusch Hospital, Vienna, Austria. All DMEKs were harvested, prepared and preloaded at the European Eye Bank of Venice, Italy. DMEK surgeries were done by one experienced surgeon and the procedure was completed by air tamponade of the anterior chamber. RESULTS: Overall, 32 eyes each of 31 endothelium-out patients and of 29 endothelium-in patients were included. 32 preloaded endothelium-in procedures were followed by 32 preloaded endothelium-out procedures. Rebubbling rate for endothelium-in was 15/32 (47%) and for endothelium-out was 7/25 (28%) (p = 0.035, Pearson's chi-squared test). Donor age was the most important variable for rebubbling in a random forest algorithm model (ROC: 0.69). CONCLUSIONS: Rebubbling rate in endothelium-out DMEK was less than two-thirds compared to endothelium-in DMEK favoring no-touch endothelium-out DMEK as the preferred technique of DMEK transplantation.

Influence of Sutureless Scleral Fixation Techniques With 3-Piece Intraocular Lenses on Dislocation Force.

PURPOSE: To compare 4 different secondary intraocular lens (IOL) fixation techniques regarding the least required force to dislocate a scleral fixated 3-piece IOL in human corneoscleral donor tissue. DESIGN: Experimental laboratory investigation. METHODS: The least required dislocation force (LRDF) of 4 different secondary IOL fixation techniques, namely, the techniques using transscleral tunnels (TTs; as described by Scharioth), glued haptics (GHs; Agarwal), flanged haptics (FHs; Yamane), and bent haptic ends (BH; Behera/Bolz), were investigated using 40 three-piece IOLs (Sensar AR40) fixated to human scleral tissue. The main outcome of the study, dislocation force between different techniques, was measured with a tensiometer. RESULTS: The force needed to dislocate the haptics was highest with the FH technique and was significantly higher than with all the other techniques (GH vs FH: -1.02±0.02 N, P < .001; TT vs FH: -1.08±0.21 N, P < .001; BH vs FH: -1.00±0.25 N, P = .044). There was no significant difference regarding the dislocation force between the other techniques: GH vs TT (-0.06±0.100 N, P = .988), GH vs BH (-0.02±0.03 N, P = .60), TT vs BH (-0.08±0.04 N, P > .99). CONCLUSIONS: The FH technique as described by Yamane proved to be the strongest form of secondary IOL fixation regarding dislocation force in this in vitro study. The other fixation techniques showed significantly less resistance to axial traction.

Dislocation force of scleral flange-fixated intraocular lens haptics.

PURPOSE: To measure the dislocation forces in relation to haptic material, flange size and needle used. SETTING: Hanusch Hospital, Vienna, Austria. DESIGN: Laboratory Investigation. METHODS, MAIN OUTCOME MEASURES: 30 G (gauge) thin wall and 27 G standard needles were used for a 2 mm tangential scleral tunnel in combination with different PVDF (polyvinylidene fluoride) and PMMA (polymethylmethacrylate haptics). Flanges were created by heating 1 mm of the haptic end, non-forceps assisted in PVDF and forceps assisted in PMMA haptics. The dislocation force was measured in non-preserved cadaver sclera using a tensiometer device. RESULTS: PVDF flanges achieved were of a mushroom-like shape and PMMA flanges were of a conic shape. For 30 G needle tunnels the dislocation forces for PVDF and PMMA haptic flanges were 1.58 ± 0.68 N (n = 10) and 0.70 ± 0.14 N (n = 9) (p = 0.003) respectively. For 27 G needle tunnels the dislocation forces for PVDF and PMMA haptic flanges were 0.31 ± 0.35 N (n = 3) and 0.0 N (n = 4), respectively. The flange size correlated with the occurring dislocation force in experiments with 30 G needle tunnels (r = 0.92), when flanges were bigger than 384 micrometres. CONCLUSIONS: The highest dislocation forces were found for PVDF haptic flanges and their characteristic mushroom-like shape for 30 G thin wall needle scleral tunnels. Forceps assisted flange creation in PMMA haptics did not compensate the disadvantage of PMMA haptics with their characteristic conic shape flange.

Attaining the optimal flange technique for transscleral capsular bag stabilization using iris hooks.

PURPOSE: To investigate the flange properties of different iris hooks. SETTING: Vienna Institute for Research in Ocular Surgery (VIROS), Hanusch Hospital, Vienna, Austria. DESIGN: Laboratory study. METHODS: The flanging properties of 4 different iris hooks made from polypropylene (PP), elastic polymer (EP), and nylon were investigated with different heating distances and both with and without forceps gripping. The maximum diameter of the flanges was measured, and the shape of the flanges was evaluated. RESULTS: Although both nylon and EP iris hooks had too small flange diameters for intrascleral fixation, PP iris hooks had a sufficient flange diameter (>330 µm) and mushroom-like shape. Furthermore, in PP hooks, heating distance was directly proportional to flange diameter. CONCLUSIONS: The findings of this study suggest that only PP iris hooks are suitable for flanged intrascleral fixation, which is off-label, to secure adequate fixation.

Size variability and fitting of 30-gauge thin-wall needles and 3-piece intraocular lens haptics for the flanged intrascleral fixation technique.

PURPOSE: To assess the diameter of different 30-gauge thin-wall needles and 3-piece intraocular lens (IOL) haptics readily used for the flanged-haptic intrascleral fixation technique. SETTING: Hanusch Hospital, Vienna, Austria. DESIGN: Laboratory investigation. METHODS: 5 30-gauge thin-wall needles and 5 3-piece IOLs were assessed. An upright light microscopy was used for measurements. The inner and outer diameters of the needles and the end thickness of the haptics were analyzed and compared for haptic fitting into the needle. RESULTS: Among the needles, the inner diameter of the T-lab needle was significantly wider compared with all the others (mean 209.3 ± 8.0 µm, P < .001), followed by TSK (194.8 ± 5.0 µm), MST (194.7 ± 5.8 µm), Sterimedix (187.5 ± 9.0 µm) and significantly narrower Meso-relle (mean 178.7 ± 7.0 µm, P < .05). The outer diameter of the T-lab needle was significantly larger of all (mean 316.0 ± 2.0 µm, P < .001). Concerning the IOLs, the AvanseePreset Kowa's haptic was significantly thinner (mean 127.2 ± 0.7 µm) than all the others, such as the TecnisZA900 Johnson & Johnson (143.5 ± 3.1 µm), the CTLucia202 Zeiss (143.8 ± 1.3 µm), and the AcrysofMA60AC Alcon (143.9 ± 1.4 µm). The only haptic that was thicker than all the others assessed was that of SensarAR40 Johnson & Johnson (170.7 ± 1.7 µm, P < .001). CONCLUSIONS: Most of the analyzed haptics would fit into most of the measured needles, with the exception of the Sensar AR40 in combination with the Meso-relle or Sterimedix needles. The combination of a larger needle lumen and a thinner haptic could result in more ease of insertion during surgery. If the dimensions of the needle and IOL haptics used are unknown, we recommend trying insertion before beginning surgery.

Diagnostic accuracy of code-free deep learning for detection and evaluation of posterior capsule opacification.

OBJECTIVE: To train and validate a code-free deep learning system (CFDLS) on classifying high-resolution digital retroillumination images of posterior capsule opacification (PCO) and to discriminate between clinically significant and non-significant PCOs. METHODS AND ANALYSIS: For this retrospective registry study, three expert observers graded two independent datasets of 279 images three separate times with no PCO to severe PCO, providing binary labels for clinical significance. The CFDLS was trained and internally validated using 179 images of a training dataset and externally validated with 100 images. Model development was through Google Cloud AutoML Vision. Intraobserver and interobserver variabilities were assessed using Fleiss kappa (κ) coefficients and model performance through sensitivity, specificity and area under the curve (AUC). RESULTS: Intraobserver variability κ values for observers 1, 2 and 3 were 0.90 (95% CI 0.86 to 0.95), 0.94 (95% CI 0.90 to 0.97) and 0.88 (95% CI 0.82 to 0.93). Interobserver agreement was high, ranging from 0.85 (95% CI 0.79 to 0.90) between observers 1 and 2 to 0.90 (95% CI 0.85 to 0.94) for observers 1 and 3. On internal validation, the AUC of the CFDLS was 0.99 (95% CI 0.92 to 1.0); sensitivity was 0.89 at a specificity of 1. On external validation, the AUC was 0.97 (95% CI 0.93 to 0.99); sensitivity was 0.84 and specificity was 0.92. CONCLUSION: This CFDLS provides highly accurate discrimination between clinically significant and non-significant PCO equivalent to human expert graders. The clinical value as a potential decision support tool in different models of care warrants further research.

Attaining optimal flange size with 5-0 and 6-0 polypropylene sutures for scleral fixation.

A technique for achieving an optimal flange size with 5-0 polypropylene and 6-0 polypropylene used for flanged intrascleral intraocular lens fixation is described. Flange size in polypropylene sutures is dependent on heating length and independent of forceps grip during heating. It was identified that heating of 1 mm created the optimal flange size for a 5-0 polypropylene suture when used for a 27-gauge needle scleral tunnel and for a 6-0 polypropylene suture when used for a 30-gauge needle scleral tunnel. Alternatively, 2 mm heating of a 6-0 polypropylene suture fits well for a 27-gauge needle tunnel. Even gentle forceps grip caused flattening of the polypropylene sutures but did not influence shaping and sizing of the flange.

The human lens: An antioxidant-dependent tissue revealed by the role of caffeine.

Cataract is the leading cause of blindness worldwide and surgery is the only option to treat the disease. Although the surgery is considered to be relatively safe, complications may occur in a subset of patients and access to ophthalmic care may be limited. Due to a growing and ageing population, an increase in cataract prevalence is expected and its management will become a socioeconomic challenge. Hence, there is a need for an alternative to cataract surgery. It is well known that oxidative stress is one of the main pathological processes leading to the generation of the disease. Antioxidant supplementation may, therefore, be a strategy to delay or to prevent the progression of cataract. Caffeine is a widely consumed high-potency antioxidant and may be of interest for the prevention of the disease. This review aims to give an overview of the anatomy and function of the lens, its antioxidant and reactive oxygen species (ROS) composition, and the role of oxidative stress in cataractogenesis. Also, the pharmacokinetics and -dynamics of caffeine will be described and the literature will be reviewed to give an overview of its anti-cataract potential and its possible role in the prevention of the disease.

Comparison of methods to experimentally induce opacification and elasticity change in ex vivo porcine lenses.

At the moment, cataract, which is the opacification of the eye's lens, can only be treated by surgery. In order to develop and test new pharmacological treatment strategies for the disease, there is a need for an appropriate in vitro model using ex vivo animal lenses. In this study, porcine lenses were incubated in either culture medium, glucose, triamcinolone acetonide, sodium chloride, hydrogen peroxide, sodium selenite, neutral buffered formalin, or were exposed to microwave heating to experimentally induce lens opacification. Changes in the lens morphology, weight, size, and elasticity were monitored 7 days after treatment. The fastest induction of dense opacification was seen in lenses exposed to sodium chloride, neutral buffered formalin, and microwave heating. No change in the size and weight of the lenses were detected, whereas loss in elasticity could be detected in lenses treated with formalin solution or microwave heating. Thus, neutral buffered formalin- and microwave-treated ex vivo porcine lenses seem to be a suitable model for mature cataracts, whereas hypertonic sodium chloride may be useful for studies on osmolarity-induced lens opacification.

Intraoperative optical coherence tomography guided corneal sweeping for removal of remnant Interface fluid during ultra-thin Descemet stripping automated endothelial keratoplasty.

BACKGROUND: Remnant interface fluid following Descemet stripping automated endothelial keratoplasty (DSAEK) is associated with postoperative detachments. The aim of this study was to assess outcomes of intraoperative optical coherence tomography (iOCT) guided meticulous peripheral corneal sweeping for removal of interface fluid during ultra-thin (UT) DSAEK. METHODS: This retrospective study included all eyes underwent iOCT guided UT-DSAEK from October 2016 to February 2018 at the Hanusch Hospital, Vienna, Austria. Peripheral meticulous corneal sweeping was performed to remove excess fluid. Central graft thickness (CGT) was measured prior to surgery, after graft bubbling and after corneal sweeping. Remnant interface fluid rates were compared between eyes that underwent rebubbling and those that did not. RESULTS: Overall, 28 eyes of 28 patients with a mean age of 73.9 ± 10.0 years were included. An iOCT guided meticulous peripheral sweeping was performed in 89.3% (n = 25) of the cases. Following 84% (n = 21) of the peripheral sweeping performed, remnant fluid was no longer identified. Following peripheral sweeping the interface fluid height was reduced from 17.31 ± 15.96 µm to 3.46 ± 9.52 µm (p < 0.001) and CGT was reduced by 7% (p < 0.001). Rebubbling was performed in 17.9% (n = 5) of the cases. The rebubbling group had a greater proportion of patients that had remnant fluid identified with iOCT at the end of surgery despite meticulous peripheral sweeping (60.0% versus 4.4%, p = 0.01). CONCLUSION: The iOCT identified subclinical remnant fluid in nearly 90% of UT-DSAEK cases. An iOCT guided peripheral corneal sweeping led to resolution of interface fluid in a majority of cases. Eyes with persistent remnant fluid despite peripheral corneal sweeping are more likely to require subsequent rebubbling.

Single high-dose peroral caffeine intake inhibits ultraviolet radiation-induced apoptosis in human lens epithelial cells in vitro.

PURPOSE: The aim of the present study was to determine whether caffeine concentrations in human lens epithelial cells (LECs) achieved from acute peroral caffeine intake inhibit ultraviolet radiation-induced apoptosis in vitro. METHODS: Patients were planned for cataract surgery of both eyes with a caffeine abstinence of 2 weeks in total, starting 1 week before surgery of the first eye. The second eye was scheduled 1 week after the first eye. At the day of the second eye surgery, patients were given coffee containing 180 mg caffeine shortly before surgery. Lens capsules including LEC, harvested after capsulorhexis, were transferred to a cell culture dish and immediately exposed to close to threshold ultraviolet radiation (UVR). At 24 hr after UVR exposure, apoptotic LECs were analysed by TdT-mediated dUTP-biotin nick end labeling (TUNEL) staining. RESULTS: TUNEL-positive cells were detected in UVR-exposed lens capsules both after caffeine intake and in controls. The mean difference in TUNEL-positive cells between caffeine intake and contralateral controls (no caffeine) resulted in a 95% CI 15.3 ± 10.4% (degrees of freedom: 16). CONCLUSION: Peroral caffeine consumption significantly decreased UVR-induced apoptosis in LEC supporting epidemiological findings that caffeine delays the onset of cataract.

UVR-B-induced NKR-1 Expression in Ocular Tissues is blocked by Substance P Receptor Antagonist Fosaprepitant in the Exposed as well as Unexposed Partner Eye.

Purpose: To investigate the effect of NKR-1 antagonists in an established UVR-B-induced cataract mouse model. Furthermore, to examine the expression of pro-inflammatory cytokines/chemokines in mouse eyes following unilateral UVR-B exposure.Methods: Mice received intraperitoneally injections of Fosaprepitant and Spantide I, before and after unilateral exposure to UVR-B. After day 3 and 7 post-exposure, ocular tissues were extracted for the detection of NKR-1 protein level by ELISA.Results: Pretreatment with Fosaprepitant decreases NKR-1 expression in exposed ocular tissues as well as in the unexposed lens epithelium compared to the saline group. Spantide I treatment showed a tendency of NKR-1 overexpression in ocular tissues.Conclusion: The clinically approved NKR-1 receptor antagonist Fosaprepitant decreases NKR-1 protein expression effectively not only in the exposed but also in the unexposed partner eye in a UVR-B irradiation mouse model. No effect was seen on the protein concentration of pro-inflammatory cytokines/chemokines in either eye.

Caffeine Uptake into the Vitreous after Peroral Coffee Consumption.

INTRODUCTION: Caffeine and its metabolites have antioxidant activity, scavenging reactive oxygen species. The aim of our study was to measure caffeine concentrations in vitreous samples after peroral caffeine intake. METHODS: This prospective study included patients scheduled for 23-G pars plana vitrectomy with membrane peeling due to epiretinal membranes. The study was performed in two parts: in the first part, patients were recruited into three different groups: group A consisted of habitual coffee drinkers who agreed to drink coffee containing 180 mg caffeine 1 h before surgery (n = 10), group B consisted of habitual coffee drinkers who were not offered coffee before surgery (n = 5), and group C consisted of non-habitual coffee drinkers, forming the control group (n = 5). In the second part (group D) patients (habitual coffee drinkers) agreed to give additional blood serum samples for measurement of caffeine concentration. Harvested samples of vitreous (groups A-D), epiretinal membranes (groups A-C), and blood serum samples (group D) were examined for concentrations of caffeine with gas chromatography-mass spectrometry. RESULTS: Samples of 40 eyes of 40 patients were harvested. The concentrations of caffeine in the vitreous samples were 1,998 ± 967 ng/mL in group A and 1,108 ± 874 ng/mL in group B. In group C, caffeine concentrations were below 176 ng/mL in all vitreous samples. Both groups A and B had significantly higher concentrations of caffeine in the vitreous samples than group C (p < 0.002, p < 0.01, Mann-Whitney U test). Caffeine concentrations in epiretinal membranes were below the limits of detection. Correlation of caffeine concentrations between blood serum samples and vitreous samples in group D was high, with significantly higher caffeine concentrations in the blood serum. CONCLUSION: Coffee consumption leads to significant caffeine levels in the vitreous compared to patients in the control group, and caffeine concentrations in the vitreous showed a high correlation to blood serum concentrations of caffeine after peroral coffee consumption.

[Effect of Dyes Containing Lutein on Enhanced Visibility of Epiretinal Pathologies in Intraoperative OCT]. / Effekt von Chromovitrektomiefarbstoffen mit Lutein auf die verbesserte Darstellung von epiretinalen Pathologien im intraoperativen OCT.

BACKGROUND: Epiretinal membranes are a disorder leading to metamorphopsia and loss in visual function. The gold standard in therapy is vitrectomy with membrane peeling, usually performed with chromovitrectomy. The aim of this study was to examine whether dyes containing lutein are capable of enhancing visualization of epiretinal tissue in intraoperative optical coherence tomography (iOCT). PATIENTS AND METHODS: This was a prospective study that included 20 eyes of 20 patients with idiopathic epiretinal membranes scheduled for surgery. 23 G pars plana vitrectomy with intraoperative assistance of iOCT was performed in all cases. Staining of epiretinal membranes was performed with dyes containing trypan blue, brilliant blue G and lutein (tripledyne and dualdyne, both Kemin Industries Inc., USA). RESULTS: In all patients (n = 20), staining of epiretinal tissue was good, and crystalline lutein particles could be well depicted in iOCT compared to soluble lutein that does not enhance visualisation of epiretinal tissue in iOCT. CONCLUSIONS: The addition of lutein to commonly used dye formulations offers good staining properties and, in case of crystalline lutein, also enhances epiretinal tissue in iOCT.

Ultraviolet Radiation Exposure of One Eye Stimulates Sympathizing Expression of Neurokinin-1 Receptor but Not Monocyte Chemoattractant Protein-1 in the Partner Eye.

PURPOSE: To investigate the influence of unilateral ultraviolet radiation (UVR) exposure on the unexposed, partner eye in vivo. To characterize the immunological cross-talk between the eyes and verify a sympathizing reaction of the partner eye via a neurokinin-dependent signaling pathway of substance P and its neurokinin-1 receptor (NKR-1) and/or monocyte chemoattractant protein-1 (MCP-1). METHODS: C57BL/6 mice were unilaterally exposed in vivo to UVR-B to a 5-fold cataract threshold equivalent dose of 14.5 kJ/m2 with a UV irradiation Bio-Spectra system. The unexposed contralateral eye was completely shielded during irradiation. After 3 and 7 days post exposure, eyes were stained with fluorescence-coupled antibody for substance P NKR-1. The same was performed in control animals receiving only anesthesia but no UVR-B exposure. NKR-1 and MCP-1 levels in ocular tissue lysates were quantified by enzyme-linked immunosorbent assay. RESULTS: UVR-B induces NKR-1 upregulation after 3 and 7 days in the exposed and in the unexposed, contralateral mouse eye. NKR-1 protein level was upregulated in the exposed and contralateral iris/ciliary body complex, choroidea and in the contralateral retina as well as in the exposed cornea. MCP-1 levels were elevated in the exposed cornea, iris/ciliary body complex, and aqueous humor but not in contralateral ocular tissues. CONCLUSIONS: UVR-B exposure triggers NKR-1 upregulation not only in the exposed but also in the unexposed, partner eye in various ocular tissues. Following UVR-B exposure, MCP-1 protein levels are upregulated in the exposed eye, but the contralateral side remains unaffected.

Automated qualitative and quantitative assessment of posterior capsule opacification by Automated Quantification of After-Cataract II (AQUA II) system.

BACKGROUND: The present study aims to investigate an automated qualitative and quantitative assessment system (Automated Quantification of After-Cataract [AQUA II]) of posterior capsule opacification (PCO) in high-resolution digital retroillumination images and consequently reduce observer bias and increase accuracy of PCO grading. METHODS: A data set of 100 eyes with no to severe PCO was analysed. Ten eyes were consecutively photographed twice and ten images were rotated to give a total of 120 images for PCO assessment. Validity was determined by including subjective grading and repeatability was determined by evaluating the 20 additional images. Evaluation of posterior capsular opacification (EPCO), posterior capsule opacity (POCO) and AQUA I methods were included for comparative analysis of the data. RESULTS: The system developed proved to classify six types of PCO. Validity was confirmed by a Pearson correlation coefficient of r = 0.95 (EPCO r = 0.93; POCO r = 0.72 and AQUA I r = 0.94). Repeatability was better in AQUA II (95% confidence interval [CI] for mean difference: 0.5 ± 1.2) than in subjective grading (95% CI for mean difference: 0.6 ± 1.7), in EPCO grading (95% CI for mean difference: - 0.2 ± 1.5), in POCO grading (95% CI for mean difference: 1.6 ± 2.7) and in AQUA I (95% CI for mean difference: - 1.1 ± 1.9). CONCLUSIONS: AQUA II is a system that for the first time not only objectively quantifies PCO, but also qualitatively assesses PCO in an automated manner with texture classification. AQUA II showed an excellent validity and repeatability.

Attaining the optimal flange for intrascleral intraocular lens fixation.

We describe a technique for making an optimal flange in intraocular lenses (IOLs) used for flanged intrascleral IOL fixation. The flange shape varies in poly(methyl methacrylate) (PMMA) haptics of different IOLs of different manufacturers. We identified the distance between the forceps grip of the haptic and the end of the haptic during heating with a cauter as a critical factor for the optimal flange shape in 5 PMMA haptics but not in 2 polyvinylidene fluoride haptics.

Pharmacokinetics of Caffeine in the Lens Capsule/Epithelium After Peroral Intake: A Pilot Randomized Controlled Study.

Purpose: To determine the pharmacokinetics of perorally administered caffeine, a widely consumed and potent dietary antioxidant, in the anterior lens capsule and lens epithelial cells, a crucial cell monolayer for cataract development. Methods: Bilateral cataract patients were scheduled for cataract surgery with a caffeine abstinence of 1 week before surgery of each eye. At the day of surgery of the second eye patients were administered no drink (0-mg group) or coffee with 60-, 120-, or 180-mg caffeine. After capsulorhexis the lens capsule including lens epithelial cells was transferred to a test tube for analysis of caffeine concentration by gas chromatography-mass spectrometry (GC-MS/MS). Results: Coffee consumption significantly (P < 0.05) increased caffeine levels of the lens capsule/epithelium in the 60-, 120-, and 180-mg group. Caffeine concentrations (caffeine ng/lens capsule/epithelium) measured as difference between 1st and 2nd eye were -0.52 ± 1.16 (0-mg group, n = 7), 1.88 ± 2.02 (60-mg group, n = 8), 2.09 ± 0.67 (120-mg group, n = 9), and 3.68 ± 1.86 (180-mg group, n = 9). The increase constant of caffeine in a linear regression model was estimated as a 95% CI 0.02 ± 0.0046 (degrees of freedom; 25; r = 0.85). Conclusions: Peroral intake of coffee significantly increased caffeine concentrations in the lens capsule and lens epithelial cells in a dose-dependent manner. This information is important for further investigations on preventing cataract.

Ultraviolet radiation exposure triggers neurokinin-1 receptor upregulation in ocular tissues in vivo.

The purpose of this study was to investigate the neurokinin receptor-1 (NKR-1) protein expression in ocular tissues before and after supra-cataract threshold ultraviolet radiation (UVR-B peak at 312 nm) exposure in vivo in a mouse model. Six-week-old C57Bl/6 mice were unilaterally exposed to a single (2.9 kJ/m2) and an above 3-fold UVR-B cataract threshold dose (9.4 kJ/m2) of UVR. UVR-exposure (λpeak = 312 nm) was performed in mydriasis using a Bio-Spectra exposure system. After latency periods of 3 and 7 days, eyes were fixed in 4% paraformaldehyde, embedded in paraffin, sectioned and stained with fluorescence coupled antibody for NKR-1 and DAPI for cell nuclei staining. Control animals received only anesthesia but no UVR-exposure. Cataract development was documented with a Leica dark-field microscope and quantified as integrated optical density (IOD). NKR-1 is ubiquitously present in ocular tissues. An above 3-fold cataract threshold dose of UV-radiation induced NKR-1 upregulation after days 3 and 7 in the epithelium and endothelium of the cornea, the endothelial cells of the iris vessels, the pigmented epithelium/stroma of the ciliary body, the lens epithelium, pronounced in the nuclear bow region and the inner plexiform layer of the retina. A significant upregulation of NKR-1 could not be provoked with a single cataract threshold dose (2.9 kJ/m2 UVR-B) ultraviolet irradiation. All exposed eyes developed anterior subcapsular cataracts. Neurokinin-1 receptor is present ubiquitously in ocular tissues including the lens epithelium and the nuclear bow region of the lens. UV-radiation exposure to an above 3-fold UVR-B cataract threshold dose triggers NKR-1 upregulation in the eye in vivo. The involvement of inflammation in ultraviolet radiation induced cataract and the role of neuroinflammatory peptides such as substance P and its receptor, NKR-1, might have been underestimated to date.