Nasolacrimal intubation in transcanalicular endoscopic dacryoplasty: a long-term follow-up study.

Nowadays, transcanalicular endoscopic dacryoplasty represents the majority of lacrimal duct surgery procedures performed in adults in specialised centers. However, there are still hardly any data available regarding the intra- and postoperative care, particularly regarding the duration of silicone tube intubation (STI). Our aim was to evaluate the relation between tube duration and recurrence of symptoms in patients who underwent transcanalicular microdrill dacryoplasty (MDP) in a long-term setting. Medical records of 576 adult patients after MDP were retrospectively reviewed. A total of 256 eyes of 191 patients could be included. The median follow-up time was 7.83 [7.08; 9.25] years. In 57.0% of the cases there was still full resolution of symptoms at the time of the survey. The median duration of the STI was 6 [3.00; 6:00] months. When distinguishing between a tube duration < 3 months and ≥ 3 months there was a significant difference in the long-term success rate (< 3 months: 38%; ≥ 3 months: 61%; p = 0.011). In conclusion, an early removal of the STI (< 3 months) after transcanalicular MDP seems to be associated with a higher incidence of recurrence of symptoms. This should be considered in the intra- and postoperative care of patients following this minimally invasive first-step procedure.

Biodegradable Nanoparticles Based on Pseudo-Proteins Show Promise as Carriers for Ophthalmic Drug Delivery.

Purpose: Drug delivery to treat ocular diseases still is a challenge in ophthalmology. One way to achieve drug delivery that is investigated currently is topical administration of drug-loaded polymeric nanoparticles (NPs) that are able to penetrate ocular barriers. The purpose of this study was optimal preparation of NPs made from pseudo-proteins and evaluation of their ability to penetrate ocular tissues. Methods: Biodegradable NPs of various types were prepared by nanoprecipitation of pseudo-protein composed of l-leucine (L), 1,6-hexanediol (6), and sebacic acid (8) (8L6). Arginine-based cationic polyester amides 8R6 and comb-like polyester amide containing lateral PEG-2000 chains along with 8L6 anchoring fragments in the backbones were used to construct positively charged and PEGylated NPs. They were loaded with fluorescein diacetate (FDA) or rhodamine 6G (Rh6G) as fluorescent probes. Suspensions of the NPs were given to cultivated microglial cells and retinal pigment epithelial (RPE) cells as well as topically on eyes of C57BL/6 mice. Penetration of NPs into the eyes was checked by fluorescence analysis. Results: NPs were prepared, and their properties were characterized. Cultured microglial cells and RPE cells took up the NPs. After topical administration, penetration of NPs into the cornea of the eyes was clearly seen. Small amounts of fluorescent dyes were also found in the lens, the retina, and the sclera depending on the type of NPs. Conclusions: The results showed that the new NPs penetrate ocular tissues after topical administration and are internalized by the cells. This raises confidence that the NPs may be useful carriers of therapeutic agents for ocular delivery.

[Optical coherence tomography angiography as a future diagnostic tool in sports medicine?] / Optische Kohärenztomographie-Angiographie als zukünftiges Diagnostikum in der Sportmedizin?

BACKGROUND: High-intensity interval training (HIIT) proved to be efficient for increasing health-related fitness in general and in patients with life style-induced chronic diseases. This study aimed to evaluate if (I) individual physical fitness and (II) a HIIT intervention affects optical coherence tomography angiography (OCTA) measurements at the ocular fundus of healthy young adults. METHODS: A total of 65 healthy participants performed a standardized incremental running test to determine their physical fitness. This was defined as speed at the individual anaerobic threshold and maximum running speed followed by a 4-week HIIT with two exercise sessions/week. The OCTA measurements of the foveal avascular zone (FAZ) and flow densities in various segments of the macula and optic nerve head were performed at rest before and after HIIT. RESULTS: An inverse correlation between individual fitness and FAZ area was detected. No further correlations between individual physical fitness and other OCTA parameters were found. In response to HIIT the mean FAZ area in the deep retinal plexus and macular flow density of the superficial layer decreased by 14.00 ± 13.02% and 1.26 ± 3.20%, respectively. The flow density of the nerve head layer in the peripapillary area showed an increase of 1.94 ± 2.39%. All other parameters showed no differences between measurements before and after HIIT. CONCLUSION: Differences were found in the OCTA measurements of the FAZ depending on the individual physical fitness. Performing HIIT can induce significant changes in certain OCTA parameters. Therefore, OCTA imaging appears to be a promising imaging modality in the field of sports medicine.

Long-term efficacy of glycerine-processed amniotic membrane transplantation in patients with corneal ulcer.

PURPOSE: The aim of this study was to determine the long-term treatment efficacy of glycerine-preserved human amniotic membrane transplantation in patients suffering from corneal ulcers. METHODS: This was a retrospective, non-controlled, monocentric analysis. Included were patients with corneal ulcers that were non-responsive to ointment or contact lenses and had been treated by amniotic membrane transplantation with either the overlay or sandwich procedure. Analysis parameters were visual acuity before and following treatment, recurrence rate and subjective comfort at the last follow-up. RESULTS: Of the 371 amniotic membrane transplantations that were conducted, 135 surgical treatments in 108 patients (51.9% male, 48.1% female; mean age 63.7 years) met the inclusion criteria. In total, 99 overlay and 36 multilayer amniotic membrane transplantations were performed. The follow-up period was 47.5 ± 66.7 weeks (mean ± SD). The recurrence rate at the last follow-up was 47.8% with overlay membranes and 51.8% with the sandwich technique. There was no significant change in best-corrected visual acuity following treatment with overlays (p = 0.219) or sandwich procedure (p = 0.703). At the last follow-up, 72.1% (overlay) and 78.3% (sandwich) of the patients reported either no pain or increased comfort. CONCLUSION: The recurrence rates and changes in visual acuity following overlay or sandwich amniotic membrane transplantation in patients suffering from corneal ulcer were lower than reported elsewhere in the literature. More than half of the patients profited from each of the amniotic membrane transplantation techniques with respect to recurrence and postoperative comfort.

Human RPE stem cells grown into polarized RPE monolayers on a polyester matrix are maintained after grafting into rabbit subretinal space.

Transplantation of the retinal pigment epithelium (RPE) is being developed as a cell-replacement therapy for age-related macular degeneration. Human embryonic stem cell (hESC) and induced pluripotent stem cell (iPSC)-derived RPE are currently translating toward clinic. We introduce the adult human RPE stem cell (hRPESC) as an alternative RPE source. Polarized monolayers of adult hRPESC-derived RPE grown on polyester (PET) membranes had near-native characteristics. Trephined pieces of RPE monolayers on PET were transplanted subretinally in the rabbit, a large-eyed animal model. After 4 days, retinal edema was observed above the implant, detected by spectral domain optical coherence tomography (SD-OCT) and fundoscopy. At 1 week, retinal atrophy overlying the fetal or adult transplant was observed, remaining stable thereafter. Histology obtained 4 weeks after implantation confirmed a continuous polarized human RPE monolayer on PET. Taken together, the xeno-RPE survived with retained characteristics in the subretinal space. These experiments support that adult hRPESC-derived RPE are a potential source for transplantation therapies.

Subretinal delivery of ultrathin rigid-elastic cell carriers using a metallic shooter instrument and biodegradable hydrogel encapsulation.

PURPOSE: To develop a surgical technique for the subretinal implantation of cell carriers suitable for the transplantation of cultured retinal pigment epithelium (RPE) in a preclinical animal model. METHODS: Cell carriers were porous 10-µm-thick polyester membranes. A custom-made shooter instrument consisted of a 20-gauge metallic nozzle with a nonstick plunger. Fetal human RPE cultures were used for vitality assessment during instrument handling. Transvitreal subretinal implantation of carriers without RPE was performed in 31 rabbits after vitrectomy. Fourteen of 31 implants were encapsulated in gelatin. Fluid turbulence over the implantation site was minimized using a novel infusion cannula. Six rabbits had intravitreal plasmin injections before surgery. SD-OCT in vivo images were obtained after 3, 7, and 14 days, followed by perfusion-fixed histology. RESULTS: Gelatin encapsulation of RPE/polyester implants made cell loss during handling reproducible, compared with 40% of controls showing random, large damage zones. Gelatin implants were ejected smoothly in 12 of 14 surgeries (86%), whereas "naked" implants frequently became trapped with the instrument, which reduced success to 9 of 17 cases (53%). Vitreous remnants after vitrectomy alone complicated subretinal placement of encapsulated and naked implants in 7 of 25 cases (28%). Plasmin-assisted vitrectomy resulted in implant ejection unperturbed by vitreous adhesions in six experiments. SD-OCT and histology demonstrated atraumatic subretinal implant delivery after uncomplicated surgery. CONCLUSIONS: A novel shooter instrument design allows for safe and atraumatic transvitreal delivery of hydrogel-encapsulated, ultrathin, rigid-elastic carriers into the subretinal space. The procedure may be used in the future to deliver cultured RPE.