New anti-angiogenic compound based on chemically modified heparin.

PURPOSE: The purpose of this study was to measure the anti-angiogenic effect of N-desulfated Re-N-acetylated, a chemically modified heparin (mHep). METHODS: In vitro assays (cell tube formation, viability, proliferation, and migration) with endothelial cells were performed after 24 h of treatment with mHep at 10, 100, and 1000 ng/mL or saline. In vivo tests were performed after laser-induced choroidal neovascularization (CNV) in rats, followed by an intravitreal injection (5 µL) of mHep (10, 100, 1000 ng/mL) or balanced salt solution. Immunofluorescence analysis of the CNV was performed after 14 days. RESULTS: mHep produced a statistically significant reduction in cell proliferation, tube formation, and migration, without cell viability changes when compared to saline. Mean measures of CNV area were 54.84 × 106 pixels/mm (± 12.41 × 106), 58.77 × 106 pixels/mm (± 17.52 × 106), and 59.42 × 106 pixels/mm (± 17.33 × 106) in groups 100, 1000, and 10,000 ng/mL, respectively, while in the control group, mean area was 72.23 × 106 (± 16.51 × 106). The P value was 0.0065. Perimeter analysis also demonstrated statistical significance (P = 0.0235) with the mean measure of 93.55 × 104, 94.23 × 104, and 102 × 104 in the 100 ng/mL, 1000 ng/mL, and control groups, respectively. CONCLUSIONS: These results suggest that mHep N-DRN is a potent anti-angiogenic, anti-proliferative, and anti-migratory compound with negligible anticoagulant or hemorrhagic action and no cytotoxicity for retina cells. This compound may serve as a candidate for treating choroidal neovascularization.

Biocompatibility of polyvinyl alcohol/trisodium trimetaphosphate as vitreous substitute in experimental vitrectomy model in rabbits.

Synthetic hydrogels have been proposed as vitreous substitutes recently. This study aims to evaluate the biocompatibility of polyvinyl alcohol (PVA) crosslinked with trisodium trimetaphosphate (SMTP) hydrogel in rabbit vitrectomized eyes. Seven animals were submitted to pars plana vitrectomy and the vitreous was replaced by PVA/SMTP hydrogel. Optical coherence tomography, fluorescein angiogram, clinical, and electrophysiological (ERG) examinations were analyzed at baseline, on postoperative days 7 and 30. The fellow eye was used as the control group. Hydrogel opacification was observed and ERG recordings were reduced in the hydrogel group in rod response, b-wave cone response and flicker. A histological analysis showed retinal disorganization, presence of multinucleated cells, and intraretinal hydrogel particles. The PVA/SMTP hydrogel showed poor biocompatibility. Novel biomaterials compounds should be analyzed in vivo.

Ocular Manifestations and Neuropathy in Type 2 Diabetes Patients With Charcot Arthropathy.

Objective: Diabetes can affect the eye in many ways beyond retinopathy. This study sought to evaluate ocular disease and determine any associations with peripheral neuropathy (PN) or cardiac autonomic neuropathy (CAN) in type 2 diabetes (T2D) and Charcot arthropathy (CA) patients. Design: A total of 60 participants were included, 16 of whom were individuals with T2D/CA, 21 of whom were individuals with T2D who did not have CA, and 23 of whom were healthy controls. Ocular surface evaluations were performed, and cases of dry eye disease (DED) were determined using the Ocular Surface Disease Index (OSDI) questionnaire, ocular surface staining, Schirmer test, and Oculus Keratograph 5M exams. All variables were used to classify DED and ocular surface disorders such as aqueous deficiency, lipid deficiency, inflammation, and ocular surface damage. Pupillary and retinal nerve fiber measurements were added to the protocol in order to broaden the scope of the neurosensory ocular evaluation. PN and CAN were ascertained by clinical examinations involving the Neuropathy Disability Score (for PN) and Ewing's battery (for CAN). Results: Most ocular variables evaluated herein differed significantly between T2D patients and controls. When the controls were respectively compared to patients with T2D and to patients with both T2D and CA, they differed substantially in terms of visual acuity (0.92 ± 0.11, 0.73 ± 0.27, and 0.47 ± 0.26, p=0.001), retinal nerve fiber layer thickness (96.83 ± 6.91, 89.25 ± 10.44, and 80.37 ± 11.67 µm, p=0.03), pupillometry results (4.10 ± 0.61, 3.48 ± 0.88, and 2.75 ± 0.81 mm, p=0.0001), and dry eye symptoms (9.19 ± 11.71, 19.83 ± 19.08, and 24.82 ± 24.40, p=0.03). DED and ocular surface damage also differed between individuals with and without CA, and were associated with PN and CAN. Conclusion: CA was found to be significantly associated with the severity of ocular findings. DED in cases of CA was also associated with PN and CAN. These findings suggest that intrinsic and complex neurosensory impairment in the eyes, peripheral sensory nerves, and the autonomic nervous system are somehow connected. Thus, a thorough ocular evaluation may be useful to highlight neurological complications and the impact of diabetes on ocular and systemic functions and structures.

Association of Weight-Adjusted Caffeine and ß-Blocker Use With Ophthalmology Fellow Performance During Simulated Vitreoretinal Microsurgery.

Importance: Vitreoretinal surgery can be technically challenging and is limited by physiologic characteristics of the surgeon. Factors that improve accuracy and precision of the vitreoretinal surgeon are invaluable to surgical performance. Objectives: To establish weight-adjusted cutoffs for caffeine and ß-blocker (propranolol) intake and to determine their interactions in association with the performance of novice vitreoretinal microsurgeons. Design, Settings, and Participants: This single-blind cross-sectional study of 15 vitreoretinal surgeons who had less than 2 years of surgical experience was conducted from September 19, 2018, to September 25, 2019, at a dry-laboratory setting. Five simulations were performed daily for 2 days. On day 1, performance was assessed after sequential exposure to placebo, low-dose caffeine (2.5 mg/kg), high-dose caffeine (5.0 mg/kg), and high-dose propranolol (0.6 mg/kg). On day 2, performance was assessed after sequential exposure to placebo, low-dose propranolol (0.2 mg/kg), high-dose propranolol (0.6 mg/kg), and high-dose caffeine (5.0 mg/kg). Interventions: Surgical simulation tasks were repeated 30 minutes after masked ingestion of placebo, caffeine, or propranolol pills during the 2 days. Main Outcomes and Measures: An Eyesi surgical simulator was used to assess surgical performance, which included surgical score (range, 0 [worst] to 700 [best]), task completion time, intraocular trajectory, and tremor rate (range, 0 [worst] to 100 [best]). The nonparametric Friedman test followed by Dunn-Bonferroni post hoc test was applied for multiple comparisons. Results: Of 15 vitreoretinal surgeons, 9 (60%) were male, with a mean (SD) age of 29.6 (1.4) years and mean (SD) body mass index (calculated as weight in kilograms divided by height in meters squared) of 23.15 (2.9). Compared with low-dose propranolol, low-dose caffeine was associated with a worse total surgical score (557.0 vs 617.0; difference, -53.0; 95% CI, -99.3 to -6.7; P = .009), a lower antitremor maneuver score (55.0 vs 75.0; difference, -12.0; 95% CI, -21.2 to -2.8; P = .009), longer intraocular trajectory (2298.6 vs 2080.7 mm; difference, 179.3 mm; 95% CI, 1.2-357.3 mm; P = .048), and increased task completion time (14.9 minutes vs 12.7 minutes; difference, 2.3 minutes; 95% CI, 0.8-3.8 minutes; P = .048). Postcaffeine treatment with propranolol was associated with performance improvement; however, surgical performance remained inferior compared with low-dose propranolol alone for total surgical score (570.0 vs 617.0; difference, -51.0; 95% CI, -77.6 to -24.4; P = .01), tremor-specific score (50.0 vs 75.0; difference, -16.0; 95% CI, -31.8 to -0.2; P = .03), and intraocular trajectory (2265.9 mm vs 2080.7 mm; difference, 166.8 mm; 95% CI, 64.1-269.6 mm; P = .03). Conclusions and Relevance: The findings suggest that performance of novice vitreoretinal surgeons was worse after receiving low-dose caffeine alone but improved after receiving low-dose propranolol alone. Their performance after receiving propranolol alone was better than after the combination of propranolol and caffeine. These results may be helpful for novice vitreoretinal surgeons to improve microsurgical performance.

Long-term Results of Trimethoprim-Sulfamethoxazole Versus Placebo to Reduce the Risk of Recurrent Toxoplasma gondii Retinochoroiditis.

PURPOSE: To compare the effects of 1 year of treatment with trimethoprim-sulfamethoxazole (TMP-SMZ) vs placebo in reducing the risk of recurrence of toxoplasmic retinochoroiditis during a 6-year follow-up period. DESIGN: Randomized, double-masked clinical trial. METHODS: This cohort included 141 subjects recruited in Campinas, Brazil. The inclusion criterion was unilateral active recurrent toxoplasmic retinochoroiditis. All subjects were treated with 1 dose of TMP-SMZ (160 mg/800 mg) twice daily for 45 days, and all lesions healed after this treatment. After this initial treatment, subjects were randomly assigned to group 1 (1 TMP-SMZ dose every other day for 311 days) or group 2 (1 identical placebo tablet containing starch with no active ingredients every other day for 311 days). Between the second and sixth years of follow-up appointments, none of the subjects received treatment unless a new recurrence episode had occurred. The primary outcomes were recurrent toxoplasmic retinochoroiditis within the first year of follow-up and recurrent toxoplasmic retinochoroiditis in the 6 years of follow-up. RESULTS: The cumulative probability of recurrence 1, 2, 3, 4, 5, and 6 years after the initial infection was, respectively, 13.0% (9/69), 17.4% (12/69), 20.3% (14/69), 23.2% (16/69), 26.1% (18/69), and 27.5% (19/69) in the placebo group and 0%, 0%, 0%, 0%, 0%, and 1.4% (1/72) in the TMP-SMZ group (P < .001; log-rank test). There were 3 cases (3/69; 4.3%) of multiple recurrences in the same individual in the placebo group. No treatment-limiting toxicity or side effects were observed in either group. New recurrences were more frequent among female subjects. CONCLUSIONS: TMP-SMZ may be used safely for prophylaxis of recurrent toxoplasmic retinochoroiditis and may provide long-term benefits.

Robot-assisted tremor control for performance enhancement of retinal microsurgeons.

Pars plana vitrectomy is a challenging, minimally invasive microsurgical procedure due to its intrinsic manoeuvres and physiological limits that constrain human capability. An important human limitation is physiological hand tremor, which can significantly increase the risk of iatrogenic retinal damage resulting from unintentional manoeuvres that affect anatomical and functional surgical outcomes. The limitations imposed by normal physiological tremor are more evident and challenging during 'micron-scale' manoeuvres such as epiretinal membrane and internal limiting membrane peeling, and delicate procedures requiring coordinated bimanual surgery such as tractional retinal detachment repair. Therefore, over the previous three decades, attention has turned to robot-assisted surgical devices to overcome these challenges. Several systems have been developed to improve microsurgical accuracy by cancelling hand tremor and facilitating faster, safer and more effective microsurgeries. By markedly reducing tremor, microsurgical precision is improved to a level beyond present human capabilities. In conclusion, robotics offers potential advantages over free-hand microsurgery as it is currently performed during ophthalmic surgery and opens the door to a new class of revolutionary microsurgical modalities. The skills transfer that is beyond human capabilities to robotic technology is a logical next step in microsurgical evolution.