Correction: Kim et al. Correlative Light and Electron Microscopy Using Frozen Section Obtained Using Cryo-Ultramicrotomy. Int. J. Mol. Sci. 2021, 22, 4273.

The authors wish to make a correction to this paper [...].

Correlative Light and Electron Microscopy Using Frozen Section Obtained Using Cryo-Ultramicrotomy.

Immuno-electron microscopy (Immuno-EM) is a powerful tool for identifying molecular targets with ultrastructural details in biological specimens. However, technical barriers, such as the loss of ultrastructural integrity, the decrease in antigenicity, or artifacts in the handling process, hinder the widespread use of the technique by biomedical researchers. We developed a method to overcome such challenges by combining light and electron microscopy with immunolabeling based on Tokuyasu's method. Using cryo-sectioned biological specimens, target proteins with excellent antigenicity were first immunolabeled for confocal analysis, and then the same tissue sections were further processed for electron microscopy, which provided a well-preserved ultrastructure comparable to that obtained using conventional electron microscopy. Moreover, this method does not require specifically designed correlative light and electron microscopy (CLEM) devices but rather employs conventional confocal and electron microscopes; therefore, it can be easily applied in many biomedical studies.

Effect of Cataract Opacity Type and Glaucoma Severity on Visual Field Index.

PURPOSE: To determine the effect of cataract opacity type and glaucoma severity on the visual field index (VFI). METHODS: A total of 152 eyes of 152 patients were analyzed. Patients with glaucoma, previous evaluation with the Swedish Interactive Threshold Algorithm-standard 24-2 VFs, visually significant cataracts, and VFs before surgery were included in this study. Cataract opacity was classified as cortical, nuclear sclerotic, or posterior subcapsular. The patients underwent phacoemulsification cataract extraction surgery. A postoperative VF test was done within 10 months of the previous VF. Glaucoma severity was classified by the postoperative mean deviation (MD) value. Changes in MD, pattern standard deviation (PSD), and VFI value before and after surgery were compared according to cataract opacity and glaucoma severity. RESULTS: The mean age at cataract surgery was 72 ± 10 years. The MD, PSD, and VFI values were less influenced by nuclear sclerotic cataract opacity. In patients with early glaucoma (MD > -6), particularly with cortical cataract opacity, MD, PSD, and VFI improved after cataract extraction (p < 0.05). Cataract opacity could make interpreting the VF indices more difficult in patients with early glaucoma. VFI was a reliable index that was less affected by cataract extraction, except in patients with early glaucoma (MD > -6) and cortical cataract opacity. CONCLUSIONS: Existing cataract opacity and the type of cataract opacity may affect the VF test results. Therefore, both glaucoma severity and the type of cataract opacity should be considered when interpreting VF results.

Effect of sorafenib on experimental choroidal neovascularization in the rat.

PURPOSE: This study was designed to evaluate the effect of sorafenib administration on laser-induced experimental choroidal neovascularization (CNV) in rats. METHODS: A total of 36 rats were divided into three groups. Sorafenib, an oral, multitargeted receptor tyrosine kinase inhibitor, was administered at a dose of 10 mg/kg per day (n = 12) or 30 mg/kg per day (n = 12) for 1 day before the laser induction of CNV. Rats continued to receive the drug for 14 days. Fluorescein angiograms were analysed for CNV dye leakage and the thickness of CNV was assessed by histology. The levels of vascular endothelial growth factor, platelet-derived growth factor, monocyte chemoattractant protein-1 and intercellular adhesion molecule-1 mRNA were measured by the use of real-time quantitative reverse-transcription polymerase chain reaction. RESULTS: Sorafenib-treated rats had significantly less fluorescence leakage as compared with vehicle-treated rats (P < 0.05), The CNV thickness in sorafenib-treated rats was significantly reduced as compared with vehicle-treated rats in a dose-dependent manner (P = 0.00163 for 10 mg/kg and P < 0.00001 for 30 mg/kg). After sorafenib (30 mg/kg) administration, expression of the vascular endothelial growth factor and intercellular adhesion molecule-1 genes was significantly decreased (P < 0.05 and P = 0.00802). CONCLUSION: These results suggest that sorafenib may be potentially beneficial for the treatment of CNV in human; further studies on this subject are warranted.

Effect of a single intraoperative sub-Tenon injection of triamcinolone acetonide on the progression of diabetic retinopathy and visual outcomes after cataract surgery.

PURPOSE: To assess the effect of a single intraoperative sub-Tenon injection of triamcinolone acetonide on the progression of diabetic retinopathy (DR), visual outcomes, and cystoid macular edema (CME) after cataract surgery. SETTING: Department of Ophthalmology and Visual Science, College of Medicine, The Catholic University of Korea, Seoul, Korea. METHODS: This prospective controlled study comprised 46 eyes of 23 diabetic patients. The control group comprised eyes not treated with a triamcinolone acetonide injection, and the triamcinolone group comprised contralateral eyes treated with a single posterior sub-Tenon injection of triamcinolone acetonide at the end of cataract surgery. The visual acuity, central macular thickness (CMT) by optical coherence tomography, and progression of DR were compared between the 2 groups. RESULTS: One month postoperatively, the mean change in lines of best corrected visual acuity was significantly greater in the triamcinolone group (P = .045) and the mean change in CMT was significantly greater in the control group (P = .015). The incidence of CME was higher in the control group (P = 0.04). Scores for progression of DR at 6 months were not statistically significantly different between the 2 groups (P = 0.08). CONCLUSIONS: A posterior sub-Tenon injection of triamcinolone acetonide lowered the incidence of CME after cataract surgery in diabetic patients, improved visual recovery, and reduced the amount of CMT increase in the short term (< or = 1 month postoperatively). However, triamcinolone acetonide did not affect DR progression over the 6-month follow-up.

The effect of Nd:YAG laser membranotomy and intravitreal tissue plasminogen activator with gas on massive diabetic premacular hemorrhage.

BACKGROUND AND OBJECTIVE: To investigate the combined therapeutic effects of Nd:YAG laser membranotomy and intravitreal tissue plasminogen activator (tPA) (Actilyse; Boehringer Ingelheim, Ingelheim, Germany) injection with perfluoropropane (C3F8, 100%) injection on massive diabetic premacular hemorrhage. PATIENTS AND METHODS: Nd:YAG laser membranotomy was performed on the hemorrhagic membrane of premacular hemorrhage, and tPA (25 microg/0.1 mL) was injected into the vitreous cavity of seven eyes with massive diabetic premacular hemorrhage. For each procedure 0.2 mL of C3F8 was also injected. RESULTS: After the combined therapy, the patients recovered vision within 4 weeks and the hemorrhages were completely absorbed within 8 weeks. Visual acuity at the last follow-up visit improved to a mean of 10 logarithm of the minimum angle of resolution lines in all cases. There were no associated ophthalmic complications. CONCLUSION: The combined therapy resulted in resolution of premacular hemorrhages with proliferative diabetic retinopathy and may allow for faster resolution of premacular hemorrhages and lessen the need for vitrectomy.

Comparison of the effect of intracameral moxifloxacin, levofloxacin and cefazolin on rabbit corneal endothelial cells.

PURPOSE: To compare the effect on corneal endothelial cells among intracameral moxifloxacin, levofloxacin and cefazoline in rabbits. METHODS: Thirty-six eyes from eighteen rabbits were divided into four groups. The control solution (balanced salt solution), cefazolin 1000 microg/0.1 mL, levofloxain 500 microg/0.1 mL or moxifloxacin 500 microg/0.1 mL was injected into the anterior chamber of the rabbit eye. The central corneal thickness was assessed before the injection of intracameral antibiotics. Endothelial toxicity was evaluated according to the central corneal thickness, specular microscopy, scanning electron microscopy and transmission electron microscopy 1 day after injection. RESULTS: Before the injection, the central corneal thickness was not different among four groups. After injection, there was no significant difference of the corneal thickness and endothelial cell count between the control and study groups. The central corneal thickness after injection of antibiotics did not significantly change when compared with control. Scanning electron microscopy showed normal hexagonality. Normal architecture of the endothelial cells was noted in transmission electron microscopy in all four groups. CONCLUSIONS: Intracameral injection of antibiotics (cefazolin 1000 microg/0.1 mL, levofloxain 500 microg/0.1 mL, moxifloxacin 500 microg/0.1 mL) did not show significant toxicity on the endothelial cells compared with the control group. Intracameral injection of one of these antibiotics appears to be safe for surgical prophylaxis.

Comparison of Nd: YAG capsulotomy rate between 1-piece and 3-piece acrylic intraocular lenses: A STROBE-compliant article.

The aim of the study is to compare Nd:YAG capsulotomy rate between acrylic 1- and 3-piece intraocular lenses. Among 924 eyes of 762 patients who received cataract surgery, we selected the 303 patients (404 eyes) implanted with an SN60WF 1-piece intraocular lens (Alcon, Fort Worth, TX) or a YA-60BBR 3-piece intraocular lens (Hoya Co., Tokyo, Japan). For intraindividual comparison, we enrolled the 17 patients implanted with an SN60WF in 1 eye and a YA-60BBR in the contralateral eye. We compared Nd:YAG capsulotomy rate between acrylic 1- and 3-piece intraocular lenses 24 months after the operation. Of the 404 eyes in this study, Nd:YAG capsulotomy was performed in 20 of 268 eyes (7.5%) in the SN60WF 1-piece intraocular lens group and 24 of 136 eyes (17.6%) in the YA-60BBR 3-piece intraocular lens group; the difference was statistically significant (P = .002). Among the 17 patients (34 eyes) who were implanted with 2 different inraocular lenses, Nd:YAG capsulotomy was performed in only 2 eyes (12%) in the SN60WF group and 9 eyes (53%) in the YA-60BBR group; the difference was statistically significant (P = .020).The authors found a significantly greater incidence of Nd:YAG capsulotomy in eyes who received 3-piece lenses compared with those who received 1-piece lenses.

Thicknesses of the fovea and retinal nerve fiber layer in amblyopic and normal eyes in children.

PURPOSE: This study was designed to assess and compare the thicknesses of the fovea and the retinal nerve fiber layer in normal children and children with amblyopia. METHODS: Optical Coherence Tomography (OCT) was performed on 26 children (52 eyes total) with unilateral amblyopia that was due to anisometropia or strabismus. OCT was also performed on 42 normal children (84 eyes), for a total of 136 eyes. Retinal thickness measurements were taken from the fovea, and the retinal nerve fiber layer thickness measurements were taken from the superior, inferior, nasal and temporal quadrants in the peripapillary region. RESULTS: The average age of the normal children was 8.5 years, and the average age of the children with amblyopia was 8.0 years. The average thickness of the fovea was 157.4 microm in normal eyes and was 158.8 microm in amblyopic eyes. The difference between the two groups was not statistically significant (p = 0.551). The thicknesses of the superior, inferior, nasal and temporal quadrants of the retinal nerve fiber layer between the normal children and the children with amblyopia were also not statistically significant (p = 0.751, 0.228, 0.696 and 0.228, respectively). However, for the children with anisometropic amblyopia and the children with strabismic amblyopia, the average thicknesses of the fovea were 146.5 microm and 173.1 microm, respectively, and the retinal nerve fiber layer thicknesses were measured to be 112.9 microm and 92.8 microm, respectively, and these were statistically significant differences (p = 0.046, 0.034, respectively). CONCLUSIONS: Normal thicknesses of the fovea and the retinal nerve fiber layers were established, and there were no differences in the fovea and the retinal nerve fiber layer thickness found between normal children and children with amblyopia.

Clinical study for the undercorrection factor in intermittent exotropia.

PURPOSE: The surgical technique for intermittent exotropia [X(T)] is quite simple. However, in many cases, the condition recurs due to any one of a number of causes, including undercorrection. This study examined the factors associated with undercorrection on X(T) patients. METHODS: The study examined 199 X(T) patients who underwent bilateral recession of the lateral rectus muscle or unilateral recession of the lateral rectus muscle and resection of the medial rectus muscle, and who were followed-up for more than a year. Patients whose near and far distance angles of deviation were 9 prism diopters (PD) or more at one year after surgery were designated as group 1. Those whose PD was 8 or below or who had orthophoria were assigned to group 2. Various factors were compared and analyzed. RESULTS: One day after surgery, group 1 showed an average overcorrection of 1.9 and 4.1 PD at near and far, respectively, and group 2 showed an average overcorrection of 6.3 and 7.6 PD at near and far, respectively. A statistically significant difference was observed between the two groups (p < 0.05). Factors such as the age of onset of strabismus, age at the time of surgery, the interval from the onset of strabismus to surgery, the preoperative angle of deviation, the dissociated vertical deviation, amblyopia, anisometropia and vertical strabismus had no influence on the undercorrection of X(T) patients (p > 0.05). CONCLUSIONS: Of the many factors that might influence the surgical results of X(T) patients, the angle of deviation during the initial postoperative period is the most important factor.

Treatment of neurotrophic keratopathy with nicergoline.

PURPOSE: The aim of this study was to determine the effect of nicergoline in patients with neurotrophic keratopathy. METHODS: This is a prospective, noncomparative interventional study. The study included 27 eyes of 24 patients with neurotrophic keratopathy who were unresponsive to conventional therapy. Patients were treated with 10 mg of oral nicergoline twice daily for at least 2 weeks. Slit-lamp examination, photography, corneal fluorescein dye testing, Cochet-Bonnet corneal sensitivity, and best-corrected visual acuity tests were performed before and after treatment. Tear nerve growth factor levels were measured before and after treatment. RESULTS: In 23 eyes (85%), epithelial defects healed completely between 7 and 30 days of treatment with nicergoline (mean, 15.6 ± 8.0 days). Epithelial defects persisted in 4 eyes (15%). The mean corneal sensitivity before and after treatment with nicergoline was 20.5 ± 8.5 and 30.2 ± 10.8 mm, respectively (P < 0.001). The best-corrected visual acuity (measured in units according to the logarithm of the minimum angle of resolution) was significantly improved from 1.1 ± 0.6 to 0.8 ± 0.6 (P < 0.001). The tear nerve growth factor levels were significantly higher ranging from 3.2 ± 0.3 to 6.2 ± 0.3 pg/mL (P < 0.001). CONCLUSIONS: Treatment with nicergoline helps patients with neurotrophic keratopathy in whom conventional treatment has failed.

Oral steroid therapy as an adjuvant treatment for severe epidemic keratoconjunctivitis in patients younger than 3 years.

PURPOSE: To evaluate the therapeutic effect of oral steroids given to patients younger than 3 years with epidemic keratoconjunctivitis (EKC) accompanied by severe eyelid edema and inflammatory ptosis, in whom eye drops were not feasible. METHODS: This study included 9 patients treated for EKC in local clinics whose condition failed to improve due to severe eyelid swelling together with difficulties in application of eye drops and pseudomembrane removal. We analyzed the extent of eyelid swelling, corneal damage, follicles, chemosis, and pseudomembrane formation in these patients before and after oral corticosteroid therapy in collaboration with the pediatrics department. RESULTS: After a mean of 1.8 ± 0.7 days of oral steroid treatment, eyelid edema, corneal damage, conjunctival injection, follicles, and chemosis improved in all patients. CONCLUSIONS: Oral steroids are an effective adjuvant treatment for EKC in patients younger than 3 years in whom eye drops could not be administered frequently due to severe eyelid edema.

Effect of cataract surgery on the progression of diabetic retinopathy.

PURPOSE: To study the effect of cataract surgery and other factors on the progression of diabetic retinopathy using the nonoperated contralateral eye as a control. SETTING: Department of Ophthalmology, Catholic University Medical College, Uijongbu St. Mary's Hospital, Seoul, Korea. METHODS: Monocular cataract surgery was performed in 75 patients who had the same degree of retinopathy or no retinopathy in both eyes preoperatively. Patients were assigned to 1 of 2 groups as follows: Group A, progression of retinopathy in the operated eye caused by cataract surgery; Group B, no progression of retinopathy bilaterally, comparable level of progression in both eyes, or more progression of retinopathy in the nonoperated eye than in the operated eye. The differences between the 2 groups in age, duration of and treatment methods for diabetes, renal function, and presence of preoperative macular edema were compared. The 1-year follow-up included evaluation of the progression of retinopathy. RESULTS: Surgery caused the retinopathy to progress in 23 patients (30.6%, Group A); 52 patients (69.4%, Group B) had no progression of retinopathy or a comparable level of retinopathy postoperatively. The operated eye had more progression of retinopathy than the nonoperated contralateral eye (P <.05). There was no significant difference between the 2 groups in age, diabetes duration, surgical method, or hypertension. Preoperative macular edema and poor renal function significantly affected the progression of diabetic retinopathy after cataract surgery (P <.05). CONCLUSIONS: Diabetic retinopathy progressed after cataract surgery. The presence of preoperative macular edema and poor renal function increased the progression of retinopathy postoperatively.

The effects of nicergoline on corneal nerve regeneration in rat corneas after photorefractive keratectomy.

PURPOSE: We wanted to investigate the effect of nicergoline on corneal nerve regeneration in rat corneas after photorefractive keratectomy (PRK). METHODS: Twenty Sprague-Dawley male rats were divided into two groups, the control group and the group that had been treated with nicergoline for 4 weeks. Corneal wound healing was evaluated by fluorescein staining after PRK. Immunofluorescent staining was performed in the rat corneas at 1 month after PRK with monoclonal antibodies for class III ß-tubulin, calcitonin gene-related peptide (CGRP), and substance P (SP). The stained nerve areas were calculated using an image-analysis program. RESULTS: The corneal wound healing rate was not significantly different between the nicergoline-treated rats and the control rats after PRK. At 1 month after PRK, the tubulin-positive, substance P-positive, and CGRP-positive nerve areas were significantly greater in the treatment group than those in the control group. CONCLUSION: Nicergoline treatment increased the corneal nerve area in the rats after they had undergone PRK. Nicergoline may help patients who have a decreased corneal sense, such as those with neurotrophic keratopathy and those patients after they undergo refractive surgery.

Safety of moxifloxacin and voriconazole in corneal storage media on porcine corneal endothelial cells.

PURPOSE: The aim of this study was to evaluate the safety of moxifloxacin and voriconazole as a supplement in corneal storage media for porcine corneal endothelial cells. METHODS: Twenty-eight eyes were divided into 4 groups. In the control group (the C group), corneal buttons were stored for 3 days in Optisol-GS. In the treatment group, the corneal buttons were preserved for 3 days in Optisol-GS mixed with 250 microg/mL moxifloxacin (M group), 100 microg/mL voriconazole (V group), and 250 microg/mL moxifloxacin plus 100 microg/mL voriconazole (MV group). We evaluated the samples via specular microscopy before and after 3 days of preservation. The mean changes of endothelial cell counts were compared among the 4 groups. Scanning electron microscopy was conducted after 3 days of preservation. RESULTS: Before the preservation, the endothelial cell counts did not differ among the 4 groups (P > 0.05). After 3 days of preservation, the endothelial cell count in the MV group was the lowest among the 4 groups (P < 0.05). After 3 days of preservation, the rate of corneal endothelial cell loss in the M and V groups did not differ significantly from the control group (P > 0.05). The rate of endothelial cell loss in the MV group was significantly higher than that of the control group (P < 0.05). Scanning electron microscopy revealed a normal mosaic pattern for the C, V, and F groups, but hexagonality was not preserved in the MV group. CONCLUSION: Preservation in Optisol-GS mixed with moxifloxacin (250 microg/mL) plus voriconazole (100 microg/mL) induced significant toxicity on the endothelial cells in porcine corneas, when compared with the control group.

The comparison of mydriatic effect between two drugs of different mechanism.

PURPOSE: To maximize effective use of mydriatic drugs through comparing the pupillary dilation effects between 1% tropicamide and 2.5% phenylephrine. METHODS: Fifty people requiring pupillary dilation were divided into 3 groups. Group 1 was treated with one drop of 1% tropicamide in the right eye and one drop of 2.5% phenylephrine in the left eye. Group 2 was treated twice during a 5-minute interval with 1% tropicamide in the right eye. Group 3 was treated twice during a 5-minute interval with 2.5% phenylephrine in the right eye. Groups 2 and 3 were treated with 2.5% phenylephrine and 1% tropicamide in the left eye, administered during a 5-minute interval. The pupillary size was measured in all groups for 40 minutes following eye drops administration. RESULTS: The mean patient age was 15.7 years. Group 1 included 10 patients, and groups 2 and 3 included 20 patients each. Eight patients in group 1 and 16 patients in group 2 developed a larger right pupil. Fourteen patients in group 3 developed a larger left pupil. CONCLUSIONS: Our study showed that 1% tropicamide, with its parasympathetic antagonistic mechanism of action, was more effective at inducing pupillary dilation than 2.5% phenylephrine, and the combination of 1% tropicamide and 2.5% phenylephrine was more effective than multiple drops of single eye drops.

Macular hole formation, spontaneous closure, and reopening in severe hypertensive chorioretinopathy.

Macular hole is rarely reported in severe hypertensive chorioretinopathy, and spontaneous closure of a macular hole is uncommon. We report a case of reopening after spontaneous closure of a full-thickness macular hole in a patient with severe hypertensive chorioretinopathy.