RECENT TRENDS IN THE CUMULATIVE INCIDENCE AND INTERVENTION PATTERNS OF RETINOPATHY OF PREMATURITY IN JAPAN: A Multicenter Analysis, 2011-2020.

PURPOSE: To investigate recent trends in the cumulative incidence and treatment patterns of retinopathy of prematurity (ROP) in Japan. METHODS: A retrospective multicenter cohort was conducted from 2011 to 2020 using the Diagnosis Procedure Combination inpatient database. Preterm newborns with birth weight <2,500 g were categorized by birth weight. The cumulative incidence of ROP, treatment patterns, and association between treatment and birth weight were investigated. RESULTS: A total of 82,683 preterm infants were identified, of whom 9,335 (11.3%) were diagnosed with ROP. The cumulative incidence of ROP increased by 15% in those with birth weight <500 g over the study period. Among the ROP infants, 20.2% received treatment, including laser photocoagulation (94.8%), intravitreal injection (3.8%), or both (1.8%). The proportion receiving laser photocoagulation decreased followed by an increase in intravitreal injection. This shift in intervention pattern was most conspicuous for those with birth weight 750 to 1,249 g. The risk ratio of receiving laser and intravitreal injection for those weighing <500 g was 24.7 (95% confidence interval, 10.5-58.2) and 28.4 (5.8-138.1), respectively, as compared with infants weighing >1,500 g. CONCLUSION: The cumulative incidence of ROP increased in infants with birth weight <500 g. A shift from laser photocoagulation to intravitreal injection was observed in the more recent years.

Cerebral ventriculomegaly in myotonic dystrophy type 1: normal pressure hydrocephalus-like appearances on magnetic resonance imaging.

BACKGROUND: Cerebral ventriculomegaly is an abnormal feature characteristic of myotonic dystrophy type 1 (DM1). This retrospective study investigated the morphologic changes accompanied by ventriculomegaly in DM1 on brain MRI. METHODS: One hundred and twelve adult patients with DM1 and 50 sex- and age-matched controls were assessed. The imaging characteristics for evaluations included the z-Evans Index (ventriculomegaly), callosal angle (CA), enlarged perivascular spaces in the centrum semiovale (CS-EPVS), temporo-polar white matter lesion (WML) on 3D fluid-attenuated inversion recovery (FLAIR), disproportionately enlarged subarachnoid-space hydrocephalus (DESH), and pathological brain atrophy. The "z-Evans Index" was defined as the maximum z-axial length of the frontal horns to the maximum cranial z-axial length. To determine the imaging characteristics and genetic information (CTG repeat numbers) that were associated with the z-Evans Index, we used binominal logistic regression analyses. RESULTS: The z-Evans Index was significantly larger in the patients than in the controls (0.30 ± 0.05 vs. 0.24 ± 0.02; p < 0.01). The z-Evans Index was independently associated with the callosal angle (p < 0.01) and pathological brain atrophy (p < 0.01) but not with age, gender, CTG repeat numbers, or CS-EPVS. Of the 34 patients older than 49 years, 7 (20.6%) were considered to have DESH. CONCLUSIONS: Our MRI study revealed a normal pressure hydrocephalus (NPH)-like appearance as a morphologic finding accompanied by ventriculomegaly in DM1 that tends to occur in elderly patients.

High-signal venous sinuses on MR angiography: discrimination between reversal of venous flow and arteriovenous shunting using arterial spin labeling.

PURPOSE: It is sometimes difficult to differentiate between high signals originating from a reverse flow on magnetic resonance angiography (MRA) and occult arteriovenous shunting. We attempted to determine whether arterial spin labeling (ASL) can be used to discriminate reversal of venous flow from arteriovenous shunting for high-signal venous sinuses on MR angiography. METHODS: Two radiologists evaluated the signals of the venous sinus on MRA and ASL obtained from 364 cases without arteriovenous shunting. In addition, the findings on MRA were compared with those on ASL in an additional 13 patients who had dural arteriovenous fistula (DAVF). RESULTS: In the 364 cases (728 sides) without arteriovenous shunting, a high signal due to reverse flow in the cavernous sinuses (CS) was observed on 99 sides (13.6%) on MRA and none on ASL. Of these cases, a high signal in the sigmoid sinus, transverse sinus, and internal jugular vein was seen on 3, 3, and 8 sides, respectively. All of these venous sinuses showed a high signal from the reverse flow on MRA images. CONCLUSION: ASL is a simple and useful MR imaging sequence for differentiating between reversal of venous flow and CS DAVF. In the sigmoid and transverse sinus, ASL showed false-positives due to the reverse flow from the jugular vein, which may be a limitation of which radiologists should be aware.

Optimal beam quality for chest flat panel detector system: realistic phantom study.

OBJECTIVE: To investigate optimal beam quality for chest flat panel detector (FPD) system by semi-quantitatively assessment using a realistic lung phantom. MATERIALS AND METHODS: Chest FPD radiographs were obtained on a realistic lung phantom with simulated lung opacities using various X-ray tube voltage levels (90-140 kV) with/without copper filter. Entrance skin dose was set to maintain identical for all images (0.1 mGy). Three chest radiologists unaware of the exposure settings independently evaluated the image quality of each simulated opacity and normal structure using a 5-point scale (+ 2: clearly superior to the standard; + 1: slightly superior to the standard; 0: equal to the standard; - 1: slightly inferior to the standard; - 2: clearly inferior to the standard). The traditional FPD image obtained at a tube voltage of 120 kV was used as the standard. The scores of image quality were statistically compared using the Wilcoxon rank test with Bonferroni correction. RESULTS: FPD images using 90-kV shot with copper filter were superior to the traditional 120-kV shot without filter with respect to the visibility of vertebra, pulmonary vessels, and nodules overlapping diaphragm and heart (p < 0.05). There was no significant difference with respect to the visibility of all other simulated lung opacities (lung nodules except for overlying diaphragm/heart and honeycomb opacity) between each tube voltage level with/without copper filter and the traditional 120-kV shot without filter. CONCLUSION: Image quality of FPD images using 90 kV with copper filtration is superior to that using standard tube voltage when dose is identical. KEY POINTS: • FPD image quality using 90 kV with filter is superior to that using traditional beam. • Ninety-kilovolt shot with copper filter may be suitable for chest FPD image. • Clinical study dealing with chest FPD beam optimization would be warranted.

Relationship between VEGF-related gene polymorphisms and brain morphology in treatment-naïve patients with first-episode major depressive disorder.

Vascular endothelial growth factor (VEGF) is involved in the development of major depressive disorder (MDD). Recently, a genome-wide association study has revealed that four VEGF-related single nucleotide polymorphisms (SNPs) (i.e., rs4416670, rs6921438, rs6993770 and rs10738760) were independently associated with circulating VEGF levels. The current study investigated the relationship between brain volume and these four SNPs in first-episode drug-naïve MDD patients. A total of 38 first-episode drug-naïve MDD patients and 39 healthy subjects (HS) were recruited and underwent high-resolution T1-weighted imaging. Blood samples were collected from all the participants for serum VEGF assays and VEGF-related SNPs genotyping. Genotype-diagnosis interactions related to whole-brain cortical thickness and hippocampal subfield volumes were evaluated for the four SNPs. The results revealed a genotype-diagnosis interaction only for rs6921438 (i.e., the MDD patients and HS with the G/G genotype versus the MDD patients and HS with A-carrier genotype) in the subiculum of the left hippocampus (p < 0.05), and not the other SNPs. There was a volume reduction in the left subiculum of G/G genotype patients compared with the other groups. The "hypochondriasis" scores of the HAMD-17 scale were significantly higher in the G/G genotype patients than the A-carrier genotype patients. The association was observed between VEGF-related SNP rs6921438 and subiculum atrophy in first-episode drug-naïve MDD patients.

Postoperative vision loss due to bilateral vitreous hemorrhage after robot-assisted laparoscopic hysterectomy: A case report.

Purpose: To report a case of bilateral vitreous hemorrhage (VH) resulting in postoperative vision loss (POVL) after robot-assisted laparoscopic hysterectomy in a 71-year-old female patient. Observations: At initial presentation, best-corrected visual acuity was hand motion at 20 cm in the right eye and 20/666 in the left eye. VH in both eyes and preretinal hemorrhage in the left eye was observed. As the hemorrhage gradually resolved, a full-thickness macular hole was discovered in the right eye, for which the patient did not agree with a surgical treatment. Conclusions and importance: This report describes a rare incidence of bilateral VH as a cause of POVL after non-ophthalmic surgery, which may be related to Trendelenburg positioning, CO2 pneumoperitoneum, and a long surgical duration. Given that POVL can cause severe visual impairment, consultation with ophthalmologists is crucial.

Encircling continuous suture technique for the management of extensive traumatic cyclodialysis: A case report.

PURPOSE: To report a surgical technique of cyclopexy, wherein two laps of encircling continuous sutures are placed around the limbus to treat refractory extensive cyclodialysis. METHODS: Color fundus photography, swept-source optical coherence tomography (OCT) for the anterior segment, and spectral-domain OCT for the macula. RESULTS: Previous attempts, including indirect cyclopexy and direct external cyclopexy with gas injection, failed to successfully resolve the severe cyclodialysis and associated hypotonic maculopathy. In the third surgery, two laps of encircling continuous sutures were placed around the limbus at the distances of 2-3 mm and 3-4 mm, along with phacoemulsification, intraocular lens implantation, and capsular tension ring placement. Following the surgery, hypotony and hypotonic maculopathy were effectively resolved, resulting in a significant improvement in visual acuity, that has been maintained over a year. CONCLUSION: The described surgical technique of encircling continuous sutures may be a viable option for the treatment of severe cyclodialysis.

Effect of magnification error and axial length on circumpapillary capillary density and retinal nerve fiber layer thickness.

This study aimed to evaluate the effect of magnification error and axial length (AL) on circumpapillary capillary density (cpCD) and circumpapillary retinal nerve fiber layer thickness (cpRNFLT) in healthy eyes. Seventy-two healthy eyes of 72 subjects with AL 24.7 ± 1.5 mm (range: 20.9-28.0 mm) were enrolled in this retrospective cross-sectional study and underwent optical coherence tomography angiography scanning. Magnification corrected measurement areas were obtained using AL upon which corrected cpCD, cpRNFLT values were determined. Relationships between AL and the percentage difference between corrected and uncorrected values (ΔcpCD, ΔcpRNFLT) as well as the effect of AL on magnification corrected cpCD, cpRNFLT were evaluated. ΔcpCD significantly increased with AL in the global, inferior nasal and superior nasal sectors (all p < 0.001). ΔcpRNFLT significantly increased with AL in global and all sectors (all p < 0.001) and the correlations were significantly stronger than that of ΔcpCD-AL in all sectors (all p < 0.001). Corrected cpCD did not associate with AL while corrected cpRNFLT demonstrated a significant positive association with AL in the global (p = 0.005) and temporal sector (p < 0.001). Magnification error led to a significant underestimation of cpCD in eyes with longer AL although its underestimation and the effect of AL was smaller in comparison to that of cpRNFLT.

Enhancing Visual Acuity through Combined Intraocular Lens Fixation, Penetrating Keratoplasty, and Vitrectomy: The Role of Temporary Landers Wide-Field Keratoprosthesis.

Introduction: Complex corneal conditions present surgical challenges and necessitate innovation. Here, we present two cases where we performed intraocular lens trans-scleral fixation using the double-needle Yamane technique, followed by penetrating keratoplasty and vitrectomy using a temporary Landers wide-field keratoprosthesis. Case Presentation: Case 1 involved a 70-year-old man with an aphakic eye of bullous keratopathy and corneal opacity owing to multiple penetrating and endothelial keratoplasty, endophthalmitis, and herpetic keratitis. His visual acuity was counting fingers at 20 cm before surgery. Penetrating keratoplasty with vitrectomy and intraocular lens scleral fixation was performed using the double-needle Yamane technique, and 10 months postoperatively, his best-corrected visual acuity improved to 0.6, presenting a clear cornea. Case 2 involved a 62-year-old man who underwent penetrating keratoplasty twice for corneal perforation and therapeutic penetrating keratoplasty with vitrectomy for traumatic globe rupture, resulting in the loss of the intraocular lens. The patient exhibited graft failure, and his best-corrected visual acuity was 0.03. Utilizing a temporary Landers wide-field keratoprosthesis, we performed penetrating keratoplasty and intraocular lens trans-scleral fixation without complications. His final best-corrected visual acuity improved to 0.15 with a clear cornea. Conclusions: Trans-scleral fixation of intraocular lens with penetrating keratoplasty, using temporary Landers wide-field keratoprosthesis, yielded positive clinical outcomes without serious complications.

Structure Function Relationships of Vessel Density and Retinal Nerve Fiber Layer Thickness in Early Glaucomatous Eyes With High Myopia.

Purpose: The purpose of this study was to evaluate the structure function relationship of circumpapillary vessel density (cpVD) with visual field sensitivity (VFS) and compare its characteristics with circumpapillary retinal nerve fiber layer thickness (cpRNFLT) in early glaucomatous (EG) and normal eyes with and without high myopia (HM). Methods: Seventy-five EG (mean deviation > -6 dB) and 7 normal eyes with HM (axial length [AL] >26.5 mm) and 111 EG and 11 normal eyes without HM were enrolled in this retrospective cross-sectional study. All patients underwent circumpapillary optical coherence tomography (OCT) and OCT angiography (OCTA) scanning with the Cirrus HD-6000 with AngioPlex OCTA (Carl Zeiss Meditec, Dublin, CA, USA). Structure function correlations were determined by comparing global, superior, inferior, and Garway-Heath sectoral values for cpVD and cpRNFLT with its corresponding 24-2 and 10-2 VFS of Humphrey Visual Field (HFA) analyzer. Results: CpVD showed no significant correlations with AL except for the nasal sector (P = 0.044), whereas cpRNFLT demonstrated significant positive association with AL in the global (P = 0.024), nasal (P = 0.020), and temporal (P < 0.001) sectors. In HM eyes, global and sectoral cpVD significantly correlated with corresponding VFS in all 24-2/10-2 VF sectors (all P < 0.05). CpVD-VFS correlation was significantly stronger than cpRNFLT-VFS in the nasal sector of HM eyes (P = 0.002) and temporal and inferior temporal sector of eyes without HM (P = 0.008 and P = 0.042, respectively). Conclusions: In EG eyes with HM, cpVD was less affected by AL in comparison to cpRNFLT and cpVD-VFS correlation was significant in all 24-2/10-2 VF sectors. AL-associated advantages of cpVD-VFS over cpRNFLT-VFS were observed.

Three-dimensional heads-up surgery in ab-interno trabeculotomy: Image processing-assisted trabeculotomy.

PURPOSE: We compared the visibility and surgeon posture between image-processing-assisted trabeculotomy (IP-LOT) using the NGENUITY® 3D visual system and conventional microsurgery (microscope-assisted trabeculotomy; MS-LOT). METHODS: IP-LOT was performed for five pig eyes. The visibility of the trabecular mesh work was evaluated on images of the trabecular mesh work and the posterior surface of the cornea (Cor) obtained under three different conditions. Images were then analyzed using ImageJ® to measure differences in luminance between the trabecular mesh work and Cor. IP-LOT was also performed for eleven human eyes, and the data were analyzed using the same approach as that used for the pig eyes. The length from the surgeon's abdomen to the operative eye (working distance) during MS-LOT and IP-LOT was measured for 12 different surgeons and compared to evaluate surgeon posture. RESULTS: Image processing significantly increased the difference in luminance between the trabecular mesh work and Cor in both pig and human eyes (p < 0.05). Moreover, the working distance in IP-LOT was significantly shorter than that in MS-LOT (p < 0.05). CONCLUSION: Our findings suggest that the NGENUITY® 3D visual system provides better trabecular mesh work visibility than a normal microscope in conventional surgical methods, and it allows surgeons to operate without moving far from the operative eye.

Effect of pigmentation intensity of trabecular meshwork cells on mechanisms of micropulse laser trabeculoplasty.

The intraocular pressure (IOP)-lowering mechanisms of micropulse laser trabeculoplasty (MLT) remain unclear. The present study was performed to investigate the mechanism of action of MLT, and to determine whether the pigmentation intensity of trabecular meshwork (TM) cells is associated with the treatment effects. Primary human TM cells were exposed to melanin granules to artificially introduce different levels of pigmentation. Micropulse (MP) laser irradiation was performed, and interleukin (IL)-1α/ß, matrix metalloproteinases (MMPs), tissue inhibitor of metalloproteinases (TIMPs), and extracellular matrix (ECM) protein expression were evaluated by RT-qPCR and immunocytochemistry. IL-1α/ß and MMP-1, -3, and -9 mRNA expression were significantly upregulated at 4 and 24 h after MP laser irradiation, respectively, but there were no significant changes in TIMP expression. The extent of these upregulation was greater in cells with strong pigmentation intensity. Protein expressions of fibronectin and collagen I were significantly decreased in cells with strong staining intensity. These results suggested that MP laser irradiation alter the MMP/TIMP ratio and enhance ECM turnover, resulting in increased outflow of aqueous humor. The pigmentation intensity of the TM tissues may affect the treatment efficacy of MLT, because TM cells with strong staining intensity showed a significantly enhanced response to MP laser irradiation.

Potential Mechanisms of Intraocular Pressure Reduction by Micropulse Transscleral Cyclophotocoagulation in Rabbit Eyes.

Purpose: To evaluate the histological changes associated with, and the potential mechanisms of, intraocular pressure (IOP) reduction by micropulse cyclophotocoagulation (MP-CPC) in rabbit eyes. Methods: MP-CPC was performed on the right eyes of Dutch belted rabbits, whereas the left eyes served as controls. The laser power settings were 250, 500, 750, 1000, 1500, and 2000 mW, 10 seconds per sweep, 100 seconds in total. IOP, outflow facility, and uveoscleral outflow tract imaging, using a fluorescent tracer, were examined at one week after MP-CPC. Changes of morphology and protein expressions in the outflow tissues, conjunctiva, and sclera were also evaluated. Results: Significant reductions in IOP after MP-CPC were observed at 500 to 1000 mW (P = 0.036 and P = 0.014, respectively). The pre-MP-CPC IOP was 11.35 ± 0.41 mm Hg. At one week after surgery, the respective IOP values in the eyes treated at 500 mW and 1000 mW were 9.45 ± 0.49 mm Hg and 7.4 ± 0.27 mm Hg, respectively. Severe ciliary body damage was observed at 1500 to 2000 mW. MMP1-3 and fibronectin expression levels in the outflow tract and ciliary body were upregulated after MP-CPC. The α-smooth muscle actin (α-SMA) was upregulated at higher power levels. MP-CPC significantly increased uveoscleral outflow, whereas the outflow facility did not change. The α-SMA, collagen, and fibronectin were significantly upregulated in the subconjunctiva and sclera. Conclusions: Reactive fibrotic responses were observed in the outflow tract, conjunctiva, and sclera after MP-CPC. A potential mechanism of IOP reduction by MP-CPC in pigmented rabbit eyes may involve increased uveoscleral outflow related to MMP upregulation.

Short-term outcomes of micropulse transscleral laser therapy using the revised delivery probe in refractory glaucoma.

PURPOSE: To evaluate the effectiveness of MicroPulse® transscleral laser therapy (MP-TLT) using both the original and revised MicroPulse P3® delivery probes in patients with refractory glaucoma. STUDY DESIGN: Retrospective study METHODS: We analyzed the data of patients with refractory glaucoma who underwent MP-TLT with the original and with the revised MicroPulse P3® Delivery Device from January 2018 to December 2020 at the University of Tokyo Hospital and who were followed up for 3 months. Patients' demographics, preoperative and postoperative intraocular pressure (IOP), medication scores, best-corrected visual acuity (BCVA), and complications were analyzed. RESULTS: This study enrolled 40 patients in both probe groups. At baseline, the mean IOP was 31.1 mmHg in the original group and 29.2 mmHg in the revised group, and it decreased to 22.6 mmHg and 21.6 mmHg after 3 months, respectively (paired t-test p=0.001, 0.001). No significant difference was noted between the number of medications and BCVA at baseline and 3 months in either probe group (paired t-test, p>0.05). Nor were any serious complications observed. CONCLUSION: MP-TLT using the revised MicroPulse P3® Delivery Device for the treatment of refractory glaucoma was effective in reducing IOP across glaucoma types with an excellent safety profile and was well-tolerated by the patients.

Optical coherence tomography findings after surgery for sub-inner limiting membrane hemorrhage due to ruptured retinal arterial macroaneurysm.

Ruptured retinal arterial macroaneurysm (RAM) can cause sub-inner limiting membrane (ILM) hemorrhage, leading to acute vision loss in the elderly. Vitrectomy has been established as an effective treatment to remove hemorrhage and facilitate visual recovery. Although optical coherence tomography (OCT) is useful for the diagnosis of sub-ILM hemorrhage before surgery, little is known about the postoperative OCT findings. Here, we retrospectively investigated the records of nine eyes of nine patients who underwent surgery for sub-ILM hemorrhage due to RAM rupture. On postoperative OCT, hyperreflectivity throughout the full thickness of the central fovea was observed in eight eyes (88.9%), and disruption of the ellipsoid/interdigitation zone (EZ/IZ) was observed in seven out of eight eyes (87.5%). The widths of the hyperreflectivity and EZ disruption gradually decreased. Visual recovery was least favorable in two eyes, in which the EZ line continuation did not recover until the final follow-up. The OCT findings corresponded to the hemorrhagic staining identified on fundus photographs in at least four eyes; as per the fundus photographs the findings persisted even after the hemorrhage was absorbed. In contrast, the OCT findings resembled the appearance before the development of a full-thickness macular hole, suggesting fragility caused by the RAM rupture.

Differential gene expression analysis using RNA sequencing: retinal pigment epithelial cells after exposure to continuous-wave and subthreshold micropulse laser.

PURPOSE: Subthreshold micropulse laser (SMPL) is more clinically efficient for the treatment of diabetic macular edema (DME) than the conventional continuous-wave (CW) laser. We aimed to characterize transcriptome changes after the application of these lasers and to compare the transcripts. METHODS: Human pluripotent stem cell-derived retinal pigment epithelial cells were exposed to laser irradiation. Differentially expressed genes (DEGs), distribution of heat shock protein (Hsp) family, gene expression profile, and gene ontology (GO) enrichment analysis based on RNA sequencing data were investigated at 3 h and 24 h after irradiation. RESULTS: CW laser induced more DEGs than SMPL (1771 vs. 520 genes). The expression of the Hsp family was confirmed in both groups: however, the induction patterns was different for different genes. GO enrichment analysis revealed that CW laser upregulated the expression of DEGs involved in vasculature development (GO: 0001944), related to apoptosis and repair after cell injury whereas SMPL upregulated the expression of DEGs involved in photoreceptor cell maintenance (GO: 0045494), photoreceptor cell development (GO: 0042461), and sensory perception of light stimuli (GO: 0050953). CONCLUSIONS: The results provide insights into the genetic responses and may contribute to the understanding of the molecular mechanisms of laser-induced thermal effects.

Diagnostic ability and sectoral structure-function relationship of circumpapillary and macular superficial vessel density in early glaucomatous eyes.

This study aimed to evaluate the diagnostic ability and sectoral structure function relationship of circumpapillary vessel density (cpVD) and macular vessel density (mVD) with optical coherence tomography angiography (OCTA) in early glaucomatous (EG) eyes. 224 EG eyes of 167 patients (mean deviation (MD) > - 6 dB) and 70 normal eyes of 70 subjects were enrolled in this retrospective cross-sectional study. All patients underwent OCT and OCTA scanning. Diagnostic abilities were evaluated with area under receiver operating characteristic curves (AUROC). Structure function relationships of superior, inferior and Garway-Heath sectoral values with its corresponding visual field (VF) sensitivity were determined using linear mixed models. AUROCs were 0.798, 0.621, 0.876 and 0.835 for cpVD, mVD, circumpapillary retinal nerve fiber layer thickness (cpRNFLT) and ganglion cell-inner plexiform layer, respectively. AUROC of cpVD was significantly lower than cpRNFLT (P = 0.010) and higher than mVD (P < 0.001). All Garway-Heath sectors of cpVD significantly correlated with its corresponding VF sensitivity except for the nasal sector. MVD also showed significant structure function relationship and the correlations were stronger in the perifoveal region (6 mm annulus) than in the parafoveal region (3 mm annulus). CpVD demonstrated moderate diagnostic ability and both cpVD and mVD demonstrated significant association with VF sensitivity in EG eyes.

A force measurement platform for a vitreoretinal surgical simulator using an artificial eye module integrated with a quartz crystal resonator.

To provide quantitative feedback on surgical progress to ophthalmologists practicing inner limiting membrane (ILM) peeling, we developed an artificial eye module comprising a quartz crystal resonator (QCR) force sensor and a strain body that serves as a uniform force transmitter beneath a retinal model. Although a sufficiently large initial force must be loaded onto the QCR force sensor assembly to achieve stable contact with the strain body, the highly sensitive and wide dynamic-range property of this sensor enables the eye module to detect the slight forceps contact force. A parallel-plate strain body is used to achieve a uniform force sensitivity over the 4-mm-diameter ILM peeling region. Combining these two components allowed for a measurable force range of 0.22 mN to 29.6 N with a sensitivity error within -11.3 to 4.2% over the ILM peeling area. Using this eye module, we measured the applied force during a simulation involving artificial ILM peeling by an untrained individual and compensated for the long-term drift of the obtained force data using a newly developed algorithm. The compensated force data clearly captured the characteristics of several types of motion sequences observed from video recordings of the eye bottom using an ophthalmological microscope. As a result, we succeeded in extracting feature values that can be potentially related to trainee skill level, such as the mean and standard deviation of the pushing and peeling forces, corresponding, in the case of an untrained operator, to 122.6 ± 95.2 and 20.4 ± 13.2 mN, respectively.

Bionic eye system mimicking microfluidic structure and intraocular pressure for glaucoma surgery training.

Among increasing eye diseases, glaucoma may hurt the optic nerves and lead to vision loss, the treatment of which is to reduce intraocular pressure (IOP). In this research, we introduce a new concept of the surgery simulator for Minimally Invasive Glaucoma Surgery (MIGS). The concept is comprised of an anterior eye model and a fluidic circulatory system. The model made of flexible material includes a channel like the Schlemm's canal (SC) and a membrane like the trabecular meshwork (TM) covering the SC. The system can monitor IOP in the model by a pressure sensor. In one of the MIGS procedures, the TM is cleaved to reduce the IOP. Using the simulator, ophthalmologists can practice the procedure and measure the IOP. First, considering the characteristics of human eyes, we defined requirements and target performances for the simulator. Next, we designed and manufactured the prototype. Using the prototype, we measured the IOP change before and after cleaving the TM. Finally, we demonstrated the availability by comparing experimental results and target performances. This simulator is also expected to be used for evaluations and developments of new MIGS instruments and ophthalmic surgery robots in addition to the surgical training of ophthalmologists.

Comparison of 12-month surgical outcomes of ab interno trabeculotomy with phacoemulsification between spatula-shaped and dual-blade microhooks.

PURPOSE: To compare 12-month clinical results of spatula-shaped and dual-blade microhooks ab interno trabeculotomy with phacoemulsification. STUDY DESIGN: Retrospective comparative study. METHODS: We conducted a retrospective chart review of Japanese open-angle glaucoma patients who underwent ab interno trabeculotomy with phacoemulsification with a 12-month follow-up. Two types of trabecular hook were used: the spatula-shaped Tanito Trabeculotomy ab interno Micro-hook® and the Kahook Dual Blade®. Changes in intraocular pressure (IOP) and medication scores comprised the main outcome metrics. We also analyzed and compared patient demographics and the occurrence of complications. RESULTS: Trabeculotomy was performed using a spatula-shaped hook in 17 eyes and a dual-blade hook in 15 eyes. Significant reductions in IOP (p < 0.001) and medication scores (p < 0.001) were noted in both groups after the 1-month time point. The percentage changes of IOP from baseline at each time point were not significantly different between groups, though there was a significant difference in medication scores at 12 months (p = 0.0192). Postoperative complications occurred similarly in both groups; one case in the dual-blade group required additional filtration surgery. CONCLUSIONS: Ab interno trabeculotomy with phacoemulsification was effective in lowering IOP both with spatula-shaped and with double-blade microhooks. At 12 months more medications were used postoperatively in the spatula-shaped microhook group; however, the reductions in the medication scores from baseline were statistically significant in both groups.