Use of lutein and zeaxanthin alone or combined with Brilliant Blue to identify intraocular structures intraoperatively

Anatomical and functional changes after internal limiting membrane peeling

Internal limiting membrane (ILM) peeling has been an acceptable step in vitrectomy surgeries for various retinal diseases such as macular hole, chronic macular edema following epiretinal membrane (ERM), and vitreoretinal traction. Despite all the benefits, this procedure has some side effects, which may lead to structural damage and functional vision loss. Light and dye toxicity may induce reversible and irreversible retina damage, which will be observed in postoperative optical coherence tomography scans. Retinal nerve fiber layer damage is attributed to ganglion cell degeneration and axonal transport alteration and dissociated optic nerve fiber layer is due to Müller cell damage. Eccentric MHs and recurrence of previous MHs may also lead to vision loss. Iatrogenic retinal damage may cause structural retinal changes without significant vision loss or progression to choroidal neovascularization. The mechanism of persistent macular edema after membrane peeling is still unclear, but it has been related to tractional trauma and blood-retina barrier damage. The reappearance of ERM is another cause of decreased vision after ILM peeling, which might be secondary to incomplete membrane removal. In glaucoma patients, ILM peeling is associated with significantly worsening the mean deviation on the visual field test after the surgery. We discussed various causes of vision loss and structural changes following ILM peeling. These causes may be attributed to the surgical procedure itself or the associated steps, instruments, and dyes used during the ILM peeling procedure.

Clinical significance of signal shadowing during intraoperative optical coherence tomography-assisted vitreoretinal surgery

This study aimed to analyze the clinical significance of signal shadowing during intraoperative optical coherence tomography (iOCT)-assisted vitreoretinal surgery caused by vitreoretinal instruments, tissue dyes, and vitreous substitutes, and to objectively quantify its impact on iOCT imaging. This is a retrospective observational study of postoperative image analysis from one hundred seventeen (117) patients who underwent iOCT-assisted vitrectomy. The image data were divided into three groups: vitreoretinal instruments, tissue dyes, and vitreous substitutes. The data was then processed using graphic software to measure the grade of picture quality distortion and compared to paired image controls without clinically perceptive interference, then analyzed statistically. The intraocular portion of all studied vitreoretinal instruments caused a high average gray level interference compared to controls ranging from 32 to 68% reduction, obscuring the area of interest significantly. The tips of the instruments produced low-grade shadowing, allowing the underlying tissue to be distinguished. The analyzed dyes demonstrated a wide interference range: ICG (- 75.12%), and triamcinolone (- 26.13%) showed dose-dependent high shadowing, while VITREODYNE™ (49.3%) and brilliant blue G (14.06%) exhibited no perceived distortions whilst increasing average gray levels. All analyzed vitreous substitutes (air, SF6, C3F8, PFCL, and silicone oil) showed an insignificant shadowing effect on iOCT. Certain dyes and vitreous substitutes produce a negligible shadowing effect compared to controls and other dyes, providing an advantage during real-time iOCT imaging. All analyzed vitreoretinal instruments showed a significant interference that should prompt the development of new imaging techniques or the implementation of materials with low-grade interference to overcome a clinically relevant shadowing effect on iOCT, maximizing the technology's visual accuracy and surgical diagnostic aid proficiency.

Safety Profile of Lutein- Versus Triamcinolone Acetonide-Based Vitreous Staining

Purpose

To assess the safety profile of a new lutein-based vitreous dye (LB-VD) formulation compared with various triamcinolone acetonide (TA) formulations with and without subsequent exposure to perfluorodecalin (PFD) in vitro.

Methods

Human adult retinal pigment epithelial cells (ARPE-19) were treated with the following formulations: undiluted preserved TA (TA-BA), diluted preserved TA (D-TA-BA), preservative-free TA (TA-PF), and LB-VD. First, cell tolerability was evaluated with MTT, LDH, and ATPlite assays after 1, 5, and 30 minutes of exposure to each tested formulation. Then, cells were sequentially exposed to formulations and PFD. After 24 hours of exposure to PFD, cell tolerability was evaluated through MTT and ATPlite assays.

Results

Among the formulations tested, LB-VD showed the highest levels of cell viability, cell metabolism, and cell proliferation and induced the lowest release of LDH, whereas the TA-based formulations demonstrated a cytotoxic effect on ARPE-19 cells in vitro. After subsequent 24-hour exposure to PFD, a greater reduction of cell viability was noted for all the formulations; however, this reduction was not significant only for the combination LB-VD-PFD, which was the best tolerated condition.

Conclusions

LB-VD showed a better safety profile compared with all TA-based formulations, even when used in combination with PFD.

Translational Relevance

In surgical practice, LB-VD may be preferred to TA-based formulations for vitreous staining in the light of its more favorable safety profile.

Vital dyes in macular hole surgery

Currently, surgical techniques, such as internal limiting membrane peeling, are used widely for macular holes, macular puckers, epiretinal membranes, diabetic macular edema, retinal detachment, retinal vein occlusions, vitreomacular traction, optic pit maculopathy, and Terson syndrome. This study aimed to highlight any differences regarding visual acuity and ocular tomography coherence changes after staining the internal limiting membrane with dilutions of Brilliant Blue G vs. lutein/zeaxanthin-based dyes. This study involved 30 eyes of 30 patients who had undergone posterior pole vitrectomy for idiopathic stage 4 macular hole. The study lot was divided in two subgroups, 15 eyes colored with Brilliant Blue and the other 15 eyes colored with lutein and zeaxanthin dyes. The association between visual prognosis, ocular tomography coherence changes and intraocular pressure was analyzed. The surgical treatment with required endoillumination levels and a 2-min period of dye using the Alcon Constellation Vision System had no negative impact on cell viability and improved visual acuity by 30%. Staining makes it easier to remove, to be quick and precise while performing macular surgeries. In has been observed that lutein and zeaxanthin dyes offer an intraoperative protective screen that protects photoreceptors more than Brilliant Blue while performing pars plana vitrectomy. Both study groups had good results in time. Surgical visualization is an evolving technology.

Cytoprotective effect of crocin and trans-resveratrol on photodamaged primary human retinal pigment epithelial cells

PURPOSE

Light-induced damage to retinal pigment epithelium during pars plana vitrectomy remains a hot topic in ophthalmology. Improvements in technology led to a change of light sources, selective filters, and shorter light exposure time. Currently, there is no satisfying solution to the problem. The aim of the study was to investigate the cytoprotective effects of crocin and resveratrol on light-induced damage to primary human retinal pigment epithelial cells in vitro.

METHODS

Primary human retinal pigment epithelial cells were exposed to light analogous to the illumination during pars plana vitrectomy. To evaluate the cytoprotective effects and potential toxicity of resveratrol and crocin, human retinal pigment epithelial cells were incubated with varying concentrations of both before 3-[4,5-dimethylthiazol-2-yl] tetrazolium bromide (MTT) viability assay. Furthermore, glutathione levels were measured to investigate synergistic antioxidant potential. Apoptosis of human retinal pigment epithelial cells was determined by a nucleosome detection enzyme-linked immunosorbent assay.

RESULTS

Crocin and resveratrol improved cell viability in photodamaged human retinal pigment epithelial cells significantly from 40.65 ± 21.99% in illuminated human retinal pigment epithelial cells and reached a peak viability of 85.64 ± 11.37% in crocin and resveratrol pretreated cells (for all: p < 0.001). In line, the combination of the supplements increased glutathione levels significantly from 39.35 ± 21.96% to 80.74 ± 10.32% (p = 0.017). No toxic effects were detected (p > 0.99). However, no change in apoptosis rates could be observed following pretreatment with crocin and resveratrol (p > 0.99).

CONCLUSION

Crocin and trans-resveratrol revealed cytoprotective effects on human retinal pigment epithelial cells supporting both supplement's development as potential perioperative treatments in light-induced retinal pigment epithelial damage.

The protective effect of zeaxanthin on human limbal and conjunctival epithelial cells against UV-induced cell death and oxidative stress

AIM

To explore the protective effect of zeaxanthin on human limbal and conjunctival epithelial cells against UV-radiation and excessive oxidative stress.

METHODS

Human limbal and conjunctival epithelial cells were isolated from cadaver and cultured in vitro. They were challenged with UVB radiation and H₂O₂ with and without zeaxanthin pretreatment. Cell viability, p38 and c-JUN NH(2)-terminal kinase (JNK) phosphorylation, IL-6, IL-8 and MCP-1 secretion and malondialdehyde (MDA) content were measured.

RESULTS

Zeaxanthin had no measurable cytotoxicity on limbal or conjunctival epithelial cells when used at concentrations of 5 µg/mL and below. At 30 mJ/cm² UVB, the pretreatment of zeaxanthin increased the percentage of live cells from 50% to 69% (P=0.01) and from 66% to 75% (P=0.05) for limbal and conjunctival epithelial cells, respectively. The concentrations of IL-6, IL-8 and MCP-1 in the culture medium reduced to 66% (for IL-6 and MCP-1) and 56% (for IL-8) of the levels without zeaxanthin. This was accompanied by reduced p38 and JNK protein phosphorylation. Pretreatment of zeaxanthin also reduced intracellular MDA content caused by H₂O₂ stimulation from 0.86 µmol/L to 0.52 µmol/L (P=0.02) in limbal epithelial cells and from 0.96 µmol/L to 0.56 µmol/L in conjunctival epithelial cells (P=0.03). However, zeaxanthin did not have significant effect on H₂O₂-induced cell death in limbal or conjunctival epithelial cells.

CONCLUSION

Zeaxanthin is an effective reagent in reducing the detrimental effect of UV-radiation and oxidative stress on ocular surface epithelial cells.

Lutein and Brilliant Blue-Based Dye for Donor Preparation and Transplantation in Descemet Membrane Endothelial Keratoplasty

PURPOSE

Trypan blue (TB) is used for visualization of the endothelium-Descemet membrane graft during Descemet membrane endothelial keratoplasty (DMEK). However, TB is assumed to have a dose-dependent toxic effect on the corneal endothelium. We retrospectively compared a lutein/zeaxanthin and Brilliant Blue (LZ/BB)-based dye for preparation and transplantation of the graft in DMEK to TB.

METHODS

In 20 patients, a dye composed of 1% LZ /0.025% BB was used, and in 22 patients, 0.06% TB was used for graft visualization in DMEK. We evaluated the rebubbling rate, best spectacle-corrected visual acuity (BSCVA), central corneal thickness (CCT), and endothelial cell density (ECD) before and 3 and 6 months after transplantation.

RESULTS

Staining of endothelium-Descemet membrane with LZ/BB was faint but sufficient. There was no significant difference between both groups, except in CCT after 3 months, which was lower in the LZ/BB group (P = 0.02). In the LZ/BB group, BSCVA improved from 0.48 ± 0.39 before DMEK to 0.19 ± 0.09 after 6 months (P < 0.05) (20% rebubbling rate). Donor ECD decreased from 2735 ± 259 cells/m preoperatively to 1876 ± 316 cells/mm (P < 0.0001) at 6 months (31.4%). CCT decreased from 642 ± 130 μm preoperatively to 519.8 ± 38 μm (P < 0.0001) at 6 months. In the TB group, BSCVA improved from 0.43 ± 0.27 to 0.17 ± 0.14 (P = 0.0003) at 6 months (30% rebubbling rate). ECD decreased from 2825 ± 263 to 1777 ± 302 cells/mm (P < 0.0001) after 6 months (36.3%), CCT from 638 ± 48 μm preoperatively to 531 ± 48 μm (P < 0.0001) at 6 months.

CONCLUSIONS

LZ/BB-based dyes are suitable for DMEK with outcomes comparable to TB. However, available formulas result in faint staining, discouraging their routine use in donors with assumed difficult preparation.

Idiopathic epiretinal membrane

BACKGROUND

Idiopathic epiretinal membrane (iERM) is a fibrocellular membrane that proliferates on the inner surface of the retina at the macular area. Membrane contraction is an important sight-threatening event and is due to fibrotic remodeling.

METHODS

Analysis of the current literature regarding the epidemiology, clinical features, and pathogenesis of iERM and fibrotic tissue contraction.

RESULTS

Epidemiologic studies report a relationship between iERM prevalence, increasing age, and posterior vitreous detachment. Clinically, iERM progresses through different stages characterized by an increased thickness and wrinkling of the membrane. Pathophysiologically, iERM formation is a fibrotic process in which myofibroblast formation and the deposition of newly formed collagens play key roles. Anomalous posterior vitreous detachment may be a key event initiating the formation of iERM. The age-related accumulation of advanced glycation end products may contribute to anomalous posterior vitreous detachment formation and may also influence the mechanical properties of the iERM.

CONCLUSION

Remodeling of the extracellular matrix at the vitreoretinal interface by aging and fibrotic changes, plays a significant role in the pathogenesis of iERM. A better understanding of molecular mechanisms underlying this process may eventually lead to the development of effective and nonsurgical approaches to treat and prevent vitreoretinal fibrotic diseases.

Dye solutions based on lutein and zeaxanthin: in vitro and in vivo analysis of ocular toxicity profiles

PURPOSE

To study the safety profile of Lutein/Zeaxanthin(L/Z)-based natural dye solutions in in vitro and in vivo models.

MATERIAL AND METHODS

In vitro cytotoxicity and cellular growth experiments were carried out on ARPE-19 and human corneal epithelial (HCE) cell lines using different L/Z-based dye solutions, either alone or in association with brilliant blue (BB) or trypan blue (TB). Light and transmission electron microscopy studies were performed seven days after intravitreal injection of dye solutions in rabbits. Electroretinogram (ERG) recordings were taken at baseline and before histopathology.

RESULTS

In vitro cytotoxicity assays demonstrated that the different L/Z-based solutions (from 0.3 to 2%), either alone or in association with BB (0.025%) or TB (0.04%), did not significantly alter mitochondrial activity (≤15%) in the cell lines tested. In addition, in vitro cell growth was inhibited by up to 60% depending on the dye solution, and in direct proportion to the concentration assayed. There was no evidence of structural alterations in the neurosensory retina, retinal pigment epithelium (RPE), or choriocapillaris-choroidal complex. b-Wave ERG records showed no significant differences (±15.2%) in comparison with baseline.

CONCLUSIONS

L/Z-based dye solutions demonstrated a safe profile in in vitro and in vivo models, and may be a useful tool for staining intraocular structures.

Lutein: a new dye for chromovitrectomy

PURPOSE

To evaluate the feasibility, advantages, and safety of a novel lutein-based dye for improving identification and removal of the vitreous, internal limiting membrane, and epiretinal membrane during chromovitrectomy in humans.

METHODS

We prospectively evaluated 12 eyes that underwent pars plana vitrectomy using the dye in patients with macular hole, epiretinal membrane, or proliferative diabetic retinopathy/tractional diabetic macular edema. One surgeon performed standard chromovitrectomy and completed a postoperative questionnaire to compare the staining with that of the available dyes. The peeled membranes were evaluated histologically. Follow-up examinations were performed on postoperative Days 1, 7, 30, 90 and 180; best-corrected visual acuity, optical coherence tomography, fluorescein angiography, autofluorescence, and visual fields were performed.

RESULTS

The green dye was deposited on the posterior pole because of its higher density than balanced saline solution; vigorous dye flushing into the vitreous cavity was unnecessary. The dye stained the posterior hyaloid/vitreous base by deposition onto the vitreous; brilliant blue stained the internal limiting membrane. The epiretinal membrane was poorly stained. The best-corrected visual acuity improved in all eyes without clinical toxicity or toxicity on images/visual fields. Histology showed effective removal of the internal limiting membrane and epiretinal membrane in all eyes.

CONCLUSION

The new dye improved intraoperative identification of the internal limiting membrane and the posterior hyaloid/vitreous base during chromovitrectomy.

Lutein and zeaxanthin toxicity with and without brilliant blue in rabbits

PURPOSE

To evaluate the safety profile of solutions containing lutein and zeaxanthin alone or associated with brilliant blue (BB).

METHODS

Twenty-eight New Zealand rabbits were used to evaluate 4 concentrations of the various dye solutions: 0.5% lutein/zeaxanthin; 0.5% lutein/zeaxanthin associated with 0.0125% BB; 0.3% lutein/zeaxanthin associated with 0.025% BB; and 0.25% lutein/zeaxanthin associated with 0.05% BB. The pHs of the dye solutions ranged from 6.5 to 7.2 and the osmolarities from 280 to 320 mOsm/mL. Each rabbit had 0.1 mL of one of the dyeing solutions injected into the vitreous cavity of the right eye, while balanced salt solution (BSS) was injected into the left eye as the control. Scotopic electroretinography responses were recorded in all eyes at different time points. The animals were sacrificed at 1 and 7 days after injection; the eyes were analyzed by light and transmission electron microscopy.

RESULTS

No significant (P>0.05) differences were seen in the a- and b-wave amplitudes among groups at any given point in time. Light and electron microscopy findings showed no significant abnormalities either, and were similar to the histological findings after intravitreal BSS injection.

CONCLUSIONS

Lutein and zeaxanthin alone or in association with BB showed a good safety profile in this experimental model.

Soluble lutein in combination with brilliant blue as a new dye for chromovitrectomy

A new dye for vitreoretinal surgery comprised of soluble lutein/zeaxanthin 1 % and brilliant blue 0.025 % is advantageous compared with other dyes currently used for chromovitrectomy, and showed no signs of toxicity at 1 month of follow-up.

PURPOSE

To evaluate the feasibility and safety of a dye [soluble lutein/zeaxanthin (LZ) 1 % and brilliant blue (BB) 0.025 %] for improving removal of vitreous, epiretinal membranes (ERM), and internal limiting membranes (ILM) in humans.

METHODS

We prospectively evaluated 18 eyes treated surgically for a macular hole or ERM. Eighteen surgeons performed chromovitrectomy using the dye, and completed a questionnaire to evaluate the efficacy and safety of the dye. . Examinations included best-corrected visual acuity and intraocular pressure measurements and optical coherence tomography, fluorescein angiography, and autofluorescence performed at baseline and days 1, 7, and 30 postoperatively.

RESULTS

The green dye was deposited on the posterior pole; vigorous dye flushing into the vitreous cavity was unnecessary. All surgeons reported that the ILM stained greenish-blue; 94.4 % reported ILM peeling adequate; the ERM stained poorly. No evidence of toxicity was observed.

CONCLUSION

The new dye deposited on the posterior pole due to its higher density. The ability to stain the ILM was similar to BB. The new dye has ability to stain the vitreous, hyaloid, and especially the ILM satisfactorily. The new dye may be useful during chromovitrectomy.