Hyung Bin Hwang

Beneficial Effects of Adjuvant Intravitreal Bevacizumab Injection on Outcomes of Ahmed Glaucoma Valve Implantation in Patients with Neovascular Glaucoma: Systematic Literature Review

PURPOSE We evaluated the effects of adjuvant intravitreal bevacizumab injection on the outcomes of Ahmed glaucoma valve (AGV) implantation in patients with neovascular glaucoma (NVG) through a systematic literature review. METHODS An extensive search of PubMed, EMBASE, and the Cochrane Library was performed in November 2014 for selection of relevant studies. The weighted mean difference of the percentage of intraocular pressure reduction (IOPR%) from baseline to endpoint was used as the primary efficacy estimate, and Mantel-Haenszel odds ratios and 95% confidence intervals (CIs) of the success rate were used as the secondary efficacy estimates. The incidence of adverse events was also documented through a review of the studies. RESULTS Six studies involving 252 patients (256 eyes) were included in this systematic review. The differences in the means and 95% CIs of the IOPR% of 6 studies showed that adjuvant bevacizumab treatment tended to be more effective than AGV implantation alone. Comparison of the outcomes of AGV implantation only with those of AGV implantation+adjuvant bevacizumab showed a success rate in favor of AGV implantation+adjuvant bevacizumab. The incidence of bleeding-associated complications such as hyphema, vitreous hemorrhage, and suprachoroidal hemorrhage was lower in association with combination treatment than with AGV implantation only. Combination treatment seemed to be associated with a lower incidence of other adverse effects such as hypotony, flat chamber, choroidal detachment/effusion, tube-associated complications, and corneal decompensation. CONCLUSION AGV implantation with adjuvant bevacizumab was more effective and had a higher success rate than surgery alone for lowering IOP in patients with NVG. The combined procedure tended to show a lower incidence of bleeding-associated complications, such as hyphema.

Phototoxic effects of an operating microscope on the ocular surface and tear film.

Purpose: We evaluated light exposure–induced dry eye syndrome by investigating the phototoxic effects of an operating microscope on the ocular surface and tear film in rabbits. Methods: Sixty eyes of 30 rabbits were divided into 3 groups based on the intensity of light exposure received from an operating microscope: Control group, no exposure to light; group A, 40,000-lx intensity for 30 minutes; and group B, 100,000-lx intensity for 30 minutes. To evaluate the potential damage to the ocular surface and tear film, Schirmer tests, rose bengal staining, and conjunctival impression cytology were performed before the light exposure and at 1, 3, and 5 days afterward. In addition, the expression of interleukin 1-beta was analyzed in tear samples. The expression of mucin 5AC was evaluated using immunofluorescence staining, and periodic acid–Schiff staining was conducted on conjunctival tissues. Corneal and conjunctival tissues were observed by means of electron microscopy. Results: Potential damage to the ocular surface and tear film was found in the light-exposed groups as evidenced by decreased aqueous tear production, devitalized corneal and conjunctival epithelial cells, squamous metaplasia of conjunctival epithelial cells, decreased conjunctival goblet cell density, decreased expression of mucin 5AC, ultrastructural cellular damage to corneal and conjunctival tissues, and increased interleukin 1-beta expression in tears. This damage was more noticeable in group B than in group A (P < 0.05). Conclusions: Light exposure from an operating microscope had phototoxic effects on the ocular surface and tear film in this in vivo experiment. These changes seemed to intensify as the intensity of the light increased. Therefore, excessive light exposure during ophthalmic procedures could be a pathogenic factor in dry eye syndrome after a surgery is performed.

Endothelial Cell Loss after Phacoemulsification according to Different Anterior Chamber Depths

Purpose. To compare the loss of corneal endothelial cells after phacoemulsification according to different anterior chamber depths (ACDs). Methods. We conducted a prospective study on 135 eyes with senile cataracts. Eyes with nuclear density grades of 2 to 4 were divided into three groups according to ACD: ACD I, 1.5 < ACD ≤ 2.5 mm; ACD II, 2.5 < ACD ≤ 3.5 mm; or ACD III, 3.5 < ACD ≤ 4.5 mm. Intraoperative mean cumulative dissipated energy (CDE) was measured. Clinical examinations included central corneal thickness (CCT) and endothelial cell count (ECC) preoperatively and 2 months postoperatively. Results. There were no significant differences in CDE among the ACD groups (P > 0.05). Endothelial cell loss was significantly higher in ACD I than in ACD III in grades 3 and 4 cataract density groups 2 months after phacoemulsification (P < 0.05). There were also more changes in CCT in all of the cataract density groups in the ACD I group compared to the ACD II and III groups 2 months postoperatively, but the difference was not statistically significant. Conclusions. Eyes with shallow ACDs, especially those with relatively hard cataract densities, can be vulnerable to more corneal endothelial cell loss in phacoemulsification surgery.

Ranibizumab Injection for Corneal Neovascularization Refractory to Bevacizumab Treatment

Vascular endothelial growth factor inhibitor is an emerging therapeutic modality for various ocular diseases with neovascularization (NV). However, for corneal NV, controversy remains regarding whether bevacizumab or ranibizumab is superior. A 32-year-old female diagnosed with herpetic keratoconjunctivitis with refractory corneal NV despite two previous subconjunctival and intrastromal bevacizumab injections, received two subconjunctival and intrastromal ranibizumab injections. Six months postoperatively, there was significant regression of the neovascular area and vessel caliber. Here, the authors report a case of improvement in corneal NV with subconjunctival and intrastromal ranibizumab injections, which was previously refractory to bevacizumab injection. The findings may suggest a new prospect in treating corneal NV.

Efficacy of Additional Glaucoma Drainage Device Insertion in Refractory Glaucoma: Case Series with a Systematic Literature Review and Meta-Analysis

Abstract Purpose: To report the efficacy of additional glaucoma drainage device (GDD) insertion in eyes with refractory glaucoma and which have a failed primary GDD. Methods: We conducted a non-comparative, retrospective study on eight eyes of eight patients who had a failed primary GDD and received an additional GDD in the same eye. Intraocular pressure (IOP), visual acuity (VA), the number of anti-glaucomatous medications, and complications were analyzed during the most recent office visit. Success was defined as an IOP between 6 and 21 mmHg and a 20% decrease in IOP after additional GDD insertion, with or without anti-glaucomatous medication. Results: The mean decrease in IOP at the final follow-up was 19.3 mmHg (56.1%). The mean number of anti-glaucomatous medications used at the final follow-up (2.38) was significantly less than the preoperative mean (3.50). Seven patients achieved the criteria for success, whereas one patient had an unsuccessful outcome because of corneal graft failure after additional GDD insertion. Conclusions: We showed that after the failure of a primary GDD, an additional GDD offered favorable IOP control and stable VA. In agreement with a review of previous literature, GDD insertion is the best option for treating refractory glaucoma, even in patients with a failed primary GDD.

The Effect of Prostaglandin Analogues on the Ciliary Zonular Fibers of the Rabbit Crystalline Lens

ABSTRACT Purpose: To evaluate the influence of prostaglandin (PG) analogues on the ciliary zonular fibers of the crystalline lens using scanning electron microscopy (SEM) of rabbit eyes, and to measure the matrix metalloproteinase (MMP) and tissue inhibitor of metalloproteinase (TIMP) levels of the aqueous humor and crystalline lens treated with topical PG analogues Methods: Fifty eyes from 25 New Zealand white rabbits were divided into five groups of five rabbits each. In the control group, balanced salt solution was administered via the topical route once a day to the eyes. The benzalkonium chloride (BAC) group was treated with 0.02% BAC, the Latanoprost group with 0.005% latanoprost, the Travoprost group with 0.004% Travoprost, and the Bimatoprost group with 0.03% Bimatoprost for 10 months. We examined the ciliary zonular fibers using SEM. We also measured the MMP and TIMP levels of the aqueous humor and crystalline lens. Results: SEM revealed some splitting of zonular fibers in eyes treated with topical PG analogues when compared with the control and BAC groups. The MMP-1 and TIMP-1 levels after treatment with the PG analogues did not differ significantly from the control and BAC groups (P > 0.05). There was no significant difference in MMP-1, MMP-3, TIMP-1, and MMP-1/TIMP-1 levels in the lens among all five groups. Conclusions: PG analogues may induce zonular change in rabbits microscopically. There was no association between zonular changes and the levels of certain types of MMP or TIMP in the aqueous humor or crystalline lens after topical treatment with PG analogues.

Distribution and Diversity of Ocular Microbial Communities in Diabetic Patients Compared with Healthy Subjects

ABSTRACT Purpose: The aim of this study was to identify differences in the major (core vs. variable) microbial genera of human subjects with and without diabetes. Methods: Bacterial 16S rRNA genes obtained from conjunctival swabs of 19 healthy subjects and 30 diabetic patients were sequenced using the Illumina MiSeq platform, and the sequencing data were analyzed using QIIME 1.9.1. To elucidate the microbial diversity in the ocular surface (OS), test programs from various bioinformatics domains were used. Results: Diversity index and rarefaction analysis showed that the microbial community of the diabetic patients was more diverse than that of the healthy subjects. Proteobacteria, Firmicutes, Actinobacteria, Cyanobacteria and Bacteroidetes were the dominant taxa present in the OS, and there was a significant difference in the relative abundance of the bacterial phyla between the diabetic patients and control subjects. Proteobacteria were more abundant in the diabetic group, whereas Firmicutes was more abundant in the control group. Analysis of bacterial taxa at the genus level showed that the core microbiome of diabetic patients comprised Acinetobacter, Burkholderia, Sphingomonas, and Ralstonia, whereas that of the controls comprised Bradyrhizobiaceae, Staphylococcus, Corynebacterium, Pseudomonas, Novosphingobium, Neisseriaceae, and Acinetobacter. Conclusions: There was a significant difference in the microbial community composition between diabetic patients and healthy subjects. A high abundance of Acinetobacter in the OS of diabetic patients may arise from the unique characteristics of the OS compared with those of other organ surfaces.

Two cases of myotonic dystrophy manifesting various ophthalmic findings with genetic evaluation.

We report two cases of myotonic dystrophy in one family; both diagnosed from genetic analysis following ophthalmic indications, but before the manifestation of systemic symptoms. A 39-year-old female visited our clinic for routine examination. Mild ptosis, sluggish pupillary response, and bilateral snowflake cataracts were found. Fundus examination revealed an increased cup-to-disc ratio (CDR) in both eyes and a defect in the retinal nerve fiber layer in the right eye. Intraocular pressure was low, but within the normal range in both eyes. Because cataracts are characteristic of myotonic dystrophy, we suggested that her 14-year-old daughter, who did not have any systemic complaints, undergo ophthalmic examination. She also had mild ptosis and snowflake cataracts. Both patients underwent genetic evaluation and were diagnosed with myotonic dystrophy caused by unstable expansion of cytosine-thymine-guanine trinucleotide repeats in the dystrophia myotonica-protein kinase gene. Ophthalmologists can diagnose myotonic dystrophy based on clinical and genetic findings, before the manifestation of systemic abnormalities.

Anterior dislocation of an empty capsular bag in a pseudophakic eye: A rare case report

Spontaneous intraocular lens (IOL) dislocation is uncommon in the absence of any ocular areas with zonular weakness or trauma. There have been no reports of spontaneous capsular bag dislocation into the anterior chamber without an IOL. We report a rare, interesting case of spontaneous capsular bag anterior dislocation, without an IOL, into the anterior chamber with no history of genetic disease, ocular trauma, or pseudoexfoliation that might predispose to a zonular abnormality.

A case of corneal cystinosis in a patient with rickets and chronic renal failure.

A 22-year-old man diagnosed with nephropathic cystinosis at the age of 4 years was found to have progressive bilateral corneal crystal deposition. He presented with severe photophobia and decreased visual acuity. Ocular cystinosis was diagnosed on observing the typical crystals. Optical coherence tomography showed multiple areas of stromal hyperreflectivity due to crystal deposits within the corneal stroma. Ex vivo transmission electron microscopy of the cornea showed pathognomonic crystal deposits in corneal stromal keratocytes. Using polymerase chain reaction sequencing of the entire coding region, we identified five gene mutations, including two unreported mutations.