Hee Young Choi

Toxicity of indocyanine green injected into the subretinal space: subretinal toxicity of indocyanine green.

Purpose To evaluate the toxicity of indocyanine green (ICG) injected into the subretinal space. Indocyanine green may come in contact with photoreceptors and retinal pigment epithelium through a macular hole during ICG-assisted peeling of the internal limiting membrane. Methods Balanced salt solution or ICG of various concentrations (0.6, 1.25, 2.5, or 5.0 mg/mL) was injected into the subretinal space of rabbit eyes and removed after 1 minute. After 3 days, 1 week, and 4 weeks, the eyes were enucleated and evaluated by light microscopy and electron microscopy. Results When the ICG of 1.25 mg/mL or higher concentration was injected into the subretinal space, degenerative changes of the photoreceptors and the retinal pigment epithelial cells were found after 3 days with light and electron microscopy. After 1 week, the outer retina was disintegrated and the photoreceptors were not found. After 4 weeks in the eyes with 1.25 mg/mL ICG, short photoreceptors and a thin outer nuclear layer were seen. In the eyes with 2.5 mg/mL or higher ICG, the photoreceptors and the outer nuclear layer were destroyed completely. Conclusion The results of this study suggest that the ICG of 1.25 mg/mL or higher concentration has toxicity to the outer retina of the rabbit and may cause adverse effects on the functional outcome after macular hole surgery.

In Vitro Study of Antiadipogenic Profile of Latanoprost, Travoprost, Bimatoprost, and Tafluprost in Human Orbital Preadiopocytes

PURPOSE To investigate the effect of prostaglandin F2α (PGF2α), latanoprost, travoprost, bimatoprost, and tafluprost on human orbital preadipocyte differentiation and intracellular lipid storage, and to reveal the potential mechanisms by which topical prostaglandin analogs induce orbital fat volume reduction and cause deep superior sulcus syndrome. METHODS Human orbital adipose precursors were treated in vitro for 24 h (day 1) with PGF2α, latanoprost, travoprost, bimatoprost, and tafluprost in their commercial formulations (1:100 dilution). Expressions of adipogenic transcription factor, peroxisome proliferator-activated receptor-gamma (PPARγ), and CCAAT-enhancer-binding protein α (C/EBPα) were determined by real-time reverse transcription-polymerase chain reaction (RT-PCR) at day 7. At 14 days, cells were stained with oil red O, intracellular lipid accumulation was evaluated by lipid absorbance, and adipocyte expression marker [Lipoprotein lipase (LPL)] was determined by real-time RT-PCR. RESULTS Our results showed that PGF2α and topical prostaglandin analogs down-regulated the expression of PPARγ and C/EBPα, and inhibited accumulation of intra-cytoplasmic lipid droplets and expression of LPL compared with the untreated control. Comparison between the 4 drugs showed that latanoprost had the weakest antiadipogenic effect, and bimatoprost induced the most significant reduction of adipogenesis. CONCLUSION Latanoprost, travoprost, bimatoprost, and tafluprost inhibited human preadipocyte differentiation and intracellular lipid accumulation. Morphologic and metabolic changes in orbital adipocytes caused by PGF2α analogs are a possible pathophysiologic explanation of superior eyelid deepening in patients with glaucoma.

Cysticidal effect on acanthamoeba and toxicity on human keratocytes by polyhexamethylene biguanide and chlorhexidine.

Purpose: To evaluate the cysticidal effect of polyhexamethylene biguanide (PHMB) and chlorhexidine on Acanthamoeba and its toxic effect on cultured human keratocytes. Methods: Each well of a twofold-diluted Acanthamoeba cyst-containing suspension of 5 × 104 cysts/mL was treated with PHMB and chlorhexidine for 8, 24, and 48 hours to determine the minimal cysticidal concentration (MCC) of each disinfectant. Human corneal keratocytes (5 × 104cells/mL) were exposed to PHMB and chlorhexidine for the same time to determine the survival rate of keratocytes. Inverted phase-contrast and electron microscopy were used to observe the morphologic changes. Results: The mean MCC of PHMB for 8, 24, and 48 hours was 9.42, 5.62, and 2.37 μg/mL, respectively. The mean MCC of chlorhexidine for 8, 24, and 48 hours was 24.32, 10.02, and 7.02 μg/mL, respectively. The respective survival rate of keratocytes at the MCC was 91.7%, 64.6%, and 49.7% for PHMB and 95.7%, 90.6%, and 78.1% for chlorhexidine, respectively. The cysts and keratocytes showed more damaged appearances after treatment with PHMB than chlorhexidine. Conclusions: PHMB and chlorhexidine showed a similar amoebicidal efficacy. However, PHMB seemed to be more toxic to keratocytes than chlorhexidine.

Edema of the Photoreceptor Layer in Vogt-Koyanagi-Harada Disease Observed Using High-Resolution Optical Coherence Tomography

Purpose To evaluate the characteristics of fluid accumulation in the uveitic stage of Vogt-Koyanagi-Harada (VKH) disease using high resolution optical coherence tomography (OCT3). Methods Twenty-eight eyes in 14 patients with VKH disease were reviewed retrospectively. These 28 eyes were divided into 19 eyes with intraretinal fluid (C group) and 9 eyes without intraretinal fluid (N group). Changes in visual acuity and fluid accumulation observed using OCT were compared between the two groups. Results Visual acuity at the time of presentation was significantly worse in the C group than in the N group (p=0.005). The photoreceptor layer appeared to be double-layered due to a cystoid space in the C group. Layered structures and strands found in the cystoid space. Expanding sponge-form edema led to the development of a cystoid space in the photoreceptor layer. Intraretinal fluid resolved earlier than subretinal fluid. There were no observed differences in visual acuity between the two groups after four days of treatment. Conclusions Accumulation of intraretinal fluid was related to poor initial visual acuity, but not to final visual acuity. High resolution OCT findings indicate that edema of the photoreceptor layer participates in the development of a cystoid space.

Reorganization of Photoreceptor Layer on Optical Coherence Tomography Concurrent with Visual Improvement after Macular Hole Surgery

To report three cases in which reorganization of the photoreceptor layer on optical coherence tomography (OCT) was concurrent with long-term visual recovery after macular hole surgery. Serial OCT scans of three eyes in which visual acuity continued to improve for 1 or more years after successful macular hole surgery were reviewed. Case 1. At postoperative four weeks, visual acuity was 20/100 with disorganized photoreceptor layer on OCT. The photoreceptor layer had been reorganized and visual acuity had improved to 20/25 by 1 year. Case 2. Two weeks after the operation, visual acuity was 20/125 and disorganization of the photoreceptor layer was noted. Visual acuity improved to 20/50 by four months. The photoreceptor layer had been partly reorganized and had appearance of a broken line. Visual acuity had improved to 20/40 and the photoreceptor layer had been reorganized further with a residual defect on OCT by 15 months. Case 3. Visual acuity at two weeks was 20/100. OCT revealed disorganization of the photoreceptor layer. Six months after the operation, the partly reorganized photoreceptor layer appeared as a broken line and visual acuity had reached 20/80. Visual acuity had improved further to 20/40 by 1 year, concurrent with improved organization of the photoreceptor layer. The reorganization of the photoreceptor layer plays a part in long-term improvement of visual acuity after macular hole surgery.

Acanthamoeba keratitis related to orthokeratology

PurposeTo report four cases of Acanthamoeba keratitis related to the overnight wearing of orthokeratology lenses.MethodsFour patients had histories of overnight wearing of orthokeratology lenses when they presented with corneal ulcers. They had used a contact lens care system irregularly with tap water.ResultsThe organism isolated by corneal scraping was Acanthamoeba. The patients were treated with polyhexamethylene biguanide (PHMB) and chlorhexidine, resulting in a resolution of ocular inflammation.ConclusionThe risk of Acanthamoeba keratitis as a potential complication of overnight orthokeratology should be considered, especially in patients with over one-year duration of contact lens wearing. Careful contact lens management is needed and tap-water rinsing should be eliminated from the lens care regimen.

Methicillin-resistant Staphylococcus aureus sclerokeratitis after pterygium excision.

Purpose: To report a case of methicillin-resistant Staphylococcus aureus (MRSA) sclerokeratitis after pterygium excision. Methods: Case report. Results: A 72-year-old woman who had undergone pterygium excision 6 months ago was referred for severe pain and decreased visual acuity. Although infectious scleritis caused by Pseudomonas was diagnosed clinically, and intravenous amikacin and ceftazidime and topical ciprofloxacin were started, there was no improvement. MRSA was grown in a cultured test, and topical and systemic vancomycin was applied and resolved the corneoscleral inflammation. Scleral patch graft and sliding conjunctival flap were performed, and no complications or recurrences were found through 14 months after treatment. Conclusions: MRSA should be considered as a possible organism in infectious scleritis after pterygium excision, especially when β-lactam antibiotic therapy is ineffective.

Magnetic resonance imaging assessment of fibrovascular ingrowth into porous polyethylene orbital implants.

Background:  To evaluate fibrovascular ingrowth into porous polyethylene orbital implants, using serial gadolinium (Gd)‐enhanced magnetic resonance imaging (MRI).

Effect of Bevacizumab on Strabismus Surgery in Rabbits

PURPOSE This study was conducted to evaluate the effect of bevacizumab on postoperative inflammation and adhesion after strabismus surgery in rabbits. METHODS Fifteen New Zealand White rabbits were used for this study. Both eyes of each of 15 rabbits underwent reinsertion of the superior rectus muscle (SRM). The right eye of each animal received a subconjunctival bevacizumab injection (2.5 mg/0.1 mL). As controls, normal saline was injected subconjunctivally in the contralateral eye. To assess acute inflammation changes, macrophages, neutrophils, and monocytes were localized in the SRM using an anti-CD11b antibody at postoperative day 1. At 4 weeks, the sites of muscle reattachment were evaluated grossly for postoperative adhesion score and histologically for collagen formation. RESULTS Infiltration of acute inflammatory cells showing CD11b+ was significantly reduced in the bevacizumab injection group (P=0.001). The difference in adhesion (SRM/conjunctiva and SRM/sclera) scores between the two groups was statistically insignificant (P=0.93 and P=0.85). Histopathologic findings revealed that muscle changes and fibrosis showed no significant difference (P=0.69) between the treated eyes and the control eyes. CONCLUSIONS The intraoperative use of bevacizumab reduced inflammatory cell infiltration in the early stage of the procedure, but it was insufficient to prevent postoperative adhesion in rabbit eyes after extraocular muscle surgery.

Endophthalmitis caused by Pseudomonas aeruginosa after phakic posterior chamber intraocular lens implantation to correct high myopia.

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