Seungsoo Rho

Influence of blue light-filtering intraocular lenses on retinal nerve fiber layer measurements by spectral-domain optical coherence tomography.

Purpose: The purpose of this study was to assess the influence of blue light-filtering intraocular lenses (IOL) on peripapillary retinal nerve fiber layer (RNFL) thickness measurements by spectral-domain (SD) optical coherence tomography (OCT). Methods: This prospective study included 50 eyes of 50 patients. Patients were randomly assigned to receive either a blue light-filtering IOL (acrysof IQ (SN60WF) [Alcon]) or a clear IOL (Tecnis (Z9003) [AMO]). The peripapillary RNFL thickness was measured using a Cirrus SD OCT before and 8 weeks after cataract surgery. Perioperative differences in RNFL thickness measurements and signal strengths (SS) were evaluated and compared in both IOL groups. Results: Thirty-nine eyes of 39 patients were included in the final analysis. There was a significant increase in average RNFL thickness and SS after cataract surgery in both IOL groups. No significant difference in perioperative changes of RNFL measurements was noted between yellow and clear IOL groups. In the multivariable analysis, the factor affecting perioperative differences of RNFL measurements was not IOL type but SS. Conclusions: Our data suggests that blue-light filtering IOL does not influence RNFL thickness measurements by Cirrus SD-OCT.

Human umbilical cord blood mononuclear cells and chorionic plate-derived mesenchymal stem cells promote axon survivalin a rat model of optic nerve crush injury

The use of mesenchymal stem cells (MSCs) in cell therapy in regenerative medicine has great potential, particularly in the treatment of nerve injury. Umbilical cord blood (UCB) reportedly contains stem cells, which have been widely used as a hematopoietic source and may have therapeutic potential for neurological impairment. Although ongoing research is dedicated to the management of traumatic optic nerve injury using various measures, novel therapeutic strategies based on the complex underlying mechanisms responsible for optic nerve injury, such as inflammation and/or ischemia, are required. In the present study, a rat model of optic nerve crush (ONC) injury was established in order to examine the effects of transplanting human chorionic plate-derived MSCs (CP-MSCs) isolated from the placenta, as well as human UCB mononuclear cells (CB-MNCs) on compressed rat optic nerves. Expression markers for inflammation, apoptosis, and optic nerve regeneration were analyzed, as well as the axon survival rate by direct counting. Increased axon survival rates were observed following the injection of CB-MNCs at at 1 week post-transplantation compared with the controls. The levels of growth-associated protein-43 (GAP-43) were increased after the injection of CB-MNCs or CP-MSCs compared with the controls, and the expression levels of hypoxia-inducible factor-1α (HIF-1α) were also significantly increased following the injection of CB-MNCs or CP-MSCs. ERM-like protein (ERMN) and SLIT-ROBO Rho GTPase activating protein 2 (SRGAP2) were found to be expressed in the optic nerves of the CP-MSC-injected rats with ONC injury. The findings of our study suggest that the administration of CB-MNCs or CP-MSCs may promote axon survival through systemic concomitant mechanisms involving GAP-43 and HIF-1α. Taken together, these findings provide further understanding of the mechanisms repsonsible for optic nerve injury and may aid in the development of novel cell-based therapeutic strategies with future applications in regenerative medicine, particularly in the management of optic nerve disorders.

Chronic Ocular Hypertensive Rat Model using Microbead Injection: Comparison of Polyurethane, Polymethylmethacrylate, Silica and Polystyene Microbeads

Abstract Purpose: To establish and assess an ocular hypertensive rat model using intracameral injection with various microbeads of different sizes and materials. Methods: Chronic elevation of intraocular pressure (IOP) was induced by the injection of various microbeads into the anterior chamber of Sprague-Dawley rat eyes. We compared the IOPs induced by the injection of different microbeads [7- and 17-µm polyurethane (PU), 7- and 15-µm polymethylmethacrylate (PMMA), 13-µm silica, and 15-µm polystyrene (PS)] and selected the appropriate microbeads for a chronic ocular hypertensive model in terms of IOP elevation and adverse events. IOP changes were observed for 4 weeks after microbead injections. Axonal degeneration was assessed with transmission electron microscopic photographs and RGC loss was assessed with retrograde labeling. Results: Seventy-eight rats were included. Three days after a single injection of microbeads, IOPs were increased by 24.0% by 7-µm PU microbeads, 101.8% by 17-µm PU microbeads, 56.6% by 7-µm PMMA microbeads, 22.0% by 15-µm PMMA microbeads, 153.0% by 13-µm silica microbeads, and 34.7% by 15-µm PS microbeads. 17-µm PU microbeads produced constant IOP elevation with good reproducibility (standard deviation of <6.5 mmHg). Silica injected eyes showed severe inflammation. Sustained IOP elevation by two injections of 17-µm PU microbeads resulted in a 42% axon loss and 36.5% RGC loss (p < 0.05, Mann–Whitney U test). Conclusions: PU microbead injections offer an applicable and versatile model for a chronic ocular hypertensive model in rats. Among several biomaterials, PU microbeads produced a more stable IOP elevation without adverse events.

Improvement of diagnostic performance regarding retinal nerve fiber layer defect using shifting of the normative database according to vessel position.

PURPOSE To evaluate the clinical efficacy of early detection of retinal nerve fiber layer (RNFL) defect in a Korean population using shifting of the normative RNFL thickness database according to vessel position. METHODS Retinal nerve fiber layer thickness data of 151 healthy eyes (normative group) and 120 validation subjects (validation group; additional healthy controls plus early glaucoma) were prospectively obtained using spectral-domain optical coherence tomography (SD-OCT) measurement. Clinical profiles and position of major retinal artery peaks (superotemporal, STa; inferotemporal, ITa) were investigated with position of RNFL peaks. Three different criteria for the lower 1% limit were adopted for the validation. Criterion 1 used normative data from the manufacturer. Criterion 2 used data from healthy volunteers. Criterion 3 used four combinations of two subgroups from data for volunteers, which were divided by the median value of STa in the superior region and that of ITa in the inferior region. The κ value was used to determine the diagnostic performance of each criterion (agreement with standard answer). RESULTS Assessment of the validation group using criterion 3 showed greater accuracy than with criterion 1 or criterion 2 (κ = 0.571, 0.774, and 0.979). Although SD-OCT specificity for RNFL defect detection was similar among the criteria (100%, 98.8%, and 98.9%), sensitivity was highest with criterion 3 (42.4%, 72.7%, and 100%) (all values; criteria 1, 2, and 3, respectively). CONCLUSIONS Shifting of the lower 1% reference line, according to vessel position, could remarkably improve the diagnostic performance regarding RNFL defect detection with SD-OCT.

Scleral fixation technique using a hydrophobic foldable intraocular lens with ring-shaped connecting bridges.

&NA; We introduce a new method of scleral fixation using a hydrophobic foldable intraocular lens (IOL) with ring‐shaped connecting bridges. A double‐armed 10‐0 polypropylene suturing needle is inserted using the routine ab externo technique. The midportion of the thread is pulled out through a main wound and cut. Using another 10‐0 polypropylene needle, the IOL is sutured at both inner ring‐shaped connecting bridges (inner shorter rim). The ring‐shaped connecting‐bridges IOL was carefully injected using the IOL cartridge with gentle pulling out of the thread. The externalized sutures were tied at the corresponding sites. All ties between 2 cut threads were performed using a European death knot. A scleral fixation outcome with the ring‐shaped connecting‐bridges IOL was similar to a poly(methyl methacrylate) IOL outcome; however, the surgeon should consider the possibility of a postoperative myopic shift. Financial Disclosure No author has a financial or proprietary interest in any material or method mentioned.

Bleb Analysis and Short-Term Results of Biodegradable Collagen Matrix-Augmented Ahmed Glaucoma Valve Implantation: 6-Month Follow-up

PURPOSE To evaluate the short-term efficacy of a biodegradable collagen matrix (BCM) as an adjuvant for Ahmed valve implantation surgery to prevent the hypertensive phase. METHODS This prospective study included 43 refractory glaucoma eyes, all followed for 6 months. Refractory glaucoma was defined as an IOP higher than 20 mm Hg with antiglaucoma eye drops without previous glaucoma surgery. Conventional method was performed in 21 eyes and BCM-augmented Ahmed valve implantation (BAAVI) in 22 eyes. In the BAAVI group, a 10 × 10 × 2-mm BCM was sutured on an Ahmed glaucoma valve FP7 model. Complete success was defined as an IOP of 21 mm Hg or lower (target IOP 1) or 17 mm Hg or lower (target IOP 2) without antiglaucoma medications and qualified success as an IOP of 21 mm Hg or lower with or without medications. Maximal bleb thickness was measured using anterior segment optical coherence tomography images. RESULTS The preoperative IOPs and numbers of preoperative antiglaucoma medications were similar for both groups. Complete target IOP 1 success rates were 38.1% and 86.4%, complete target IOP 2 success rates were 19.0% and 59.1%, and qualified success rates were 52.4% and 90.9% in the conventional and BAAVI groups, respectively (P < 0.05). The hypertensive phase rate was lower in the BAAVI group (4.5% vs. 47.6%, P = 0.002). Maximal bleb thickness was increased in the BAAVI group on postoperative days 30 and 180 (P < 0.05). CONCLUSIONS Success rates were higher in the BAAVI group than in the conventional group with the change of bleb morphology. Furthermore, use of BCM significantly decreased the need for antiglaucoma medications for at least 6 months postoperatively.

Clinical and Biological Evaluations of Biodegradable Collagen Matrices for Glaucoma Drainage Device Implantation

Purpose To characterize the clinical and biological properties of biodegradable collagen matrices (BCMs) for possible glaucoma drainage device implantation. Methods A total of 68 refractory glaucoma eyes, followed up postoperatively for at least 6 months, were consecutively enrolled after retrospective chart review. The BCM-augmented Ahmed valve implantations (BAAVI) using our Ologen-6 and Ologen-7 valves were performed and compared with a conventional method. Complete surgical success was defined as an IOP of ≤21 mm Hg (IOP 1) or ≤17 mm Hg (IOP 2) without antiglaucoma medications. Qualified success was defined as an IOP ≤21 mm Hg with or without antiglaucoma medications. The biological properties of each BCM were assessed by enzymatic degradation rates via collagenase under ocular physiological conditions. Results The mean ages and preoperative IOPs were similar for the groups. In the conventional, BAAVI with Ologen-6, and BAAVI with Ologen-7 groups, complete success rates with target IOP 1 were 29.2%, 40.0%, and 66.7%; those with target IOP 2 were 12.5%, 30.0%, and 45.8%; qualified success rates were 45.8%, 55.0%, and 75.0%, respectively. The enzymatic degradation rate of Ologen-7 was significantly slower than that of Ologen-6 (12.5 × 10-3 vs. 28.8 × 10-3). Conclusions The surgical success rate was highest in the Ologen-7 BAAVI group, with the lowest dependency on postoperative antiglaucoma medication use compared with the conventional and Ologen-6 BAAVI groups. The clinical results correlated with the different biological and physicochemical properties based on the degree of enzymatic degradation and on the structural morphology.

Long-term Results of Deep Sclerectomy with Small Collagen Implant in Korean

Purpose To describe the long-term results of deep sclerectomy with collagen implant (DSCI) with or without adjuvant mitomycin C in Korean patients with primary or secondary open-angle glaucoma (OAG). Methods This retrospective review was comprised of 65 Korean patients who received DSCI with or without adjuvant mitomycin C due to primary or secondary OAG. Patients were followed for 72 months after surgery. Complete success was defined as intraocular pressure (IOP) <21 mmHg without medication and qualified success was defined as IOP <21 mmHg with or without medication. Results Mean postoperative follow-up period was 53.0 ± 16.2 months. Mean IOP was 30.5 ± 11.7 mmHg preoperatively, 8.4 ± 4.3 mmHg at postoperative day one and 13.4 ± 3.8 mmHg 60 months after surgery. The mean number of glaucoma medications was decreased from 3.6 ± 1.1 to 1.6 ± 1.3 at 60 months after the operation. Complete and qualified success rates were 36.7% and 79.6% at postoperative 60 months, respectively (Kaplan-Meier survival curve). No shallow or flat anterior chamber, endophthalmitis, or surgery-induced significant cataract was observed. Conclusions The results of DSCI in Korean patients presented here seem reasonably excellent with qualified success rates of over 70% at six years with negligible complications.

Agreement of New Automated Matched Alternation Flicker using Undilated Fundus Photography for the Detection of Glaucomatous Structural Change

ABSTRACT Purpose: To determine the agreement among glaucoma experts and general ophthalmologists regarding detection of glaucomatous structural changes using a new automated matched alternation flicker (AMAF) method with fundus photographs (FPs) of undilated eyes. Methods: Sixty-six pairs of FPs of normal tension glaucoma patients were collected. FPs were taken at intervals of more than 12 months. Alternating flicker images were created using a new AMAF application. In a blinded manner, two glaucoma experts and two general ophthalmologists compared the presence of glaucomatous structural changes using either the AMAF method or the side-by-side comparison method. The interobserver and intraobserver agreements were compared using the Bland and Altman plot analysis. Results: The glaucoma experts detected more glaucoma progression using the AMAF method (average, 50.7%) compared with the side-by-side method (average, 32.5%). General ophthalmologists detected more glaucomatous progression with the AMAF method (average, 40.9%) than with the side-by-side method (average, 25.0%). The AMAF method showed fair to substantial interreader agreement (k = 0.511–0.724) and fair to perfect intrareader agreement (k = 0.631–0.943). Interreader and intrareader agreements using the AMAF method were better for the glaucoma experts compared with the general ophthalmologists. Conclusions: The AMAF method showed more changes in FPs than the classical side-by-side comparison method. Regarding inter- and intrareader agreements, agreement for the glaucoma experts was best using the AMAF method, but for the general ophthalmologists agreement was best using the side-by-side comparison method.