A case of bilateral amyloidosis localized to extraocular muscles mimicking thyroid eye disease.

BACKGROUND: Amyloidosis is a rare condition characterized by the abnormal deposition of amyloid proteins in various tissues and organs. While systemic amyloidosis has been well-documented, amyloid deposition in extraocular muscles is an exceptionally rare occurrence, with only 35 reported cases. This case report sheds light on the importance of considering amyloidosis in the differential diagnosis of patients presenting with proptosis and diplopia, which are often associated with thyroid eye disease. CASE PRESENTATION: A woman in her twenties sought medical attention due to a complaint of diplopia. Her ocular examination revealed almost normal findings except for exotropia and proptosis. Orbital magnetic resonance imaging displayed fusiform enlargement of nearly all eye muscles, a presentation typically observed in thyroid eye disease. However, despite corticosteroid therapy, her symptoms showed no improvement. Given the unusual lack of response to conventional treatment, and inhomogeneous enhancement of the muscle, an extraocular muscle biopsy was conducted. This biopsy yielded a unique finding-amyloid deposition within the muscle tissue. This discovery was particularly intriguing due to the extreme rarity of amyloidosis affecting extraocular muscles, with fewer than three dozen documented cases worldwide. CONCLUSION: This unique case underscores the critical need for a comprehensive approach to diagnosing patients with proptosis and diplopia. While these symptoms are commonly attributed to thyroid eye disease, it is essential to consider alternative diagnoses such as amyloidosis, especially when standard treatments fail to yield results. The discovery of amyloid deposition in the extraocular muscles, although exceedingly rare, emphasizes the significance of a thorough differential diagnosis. In conclusion, this case report highlights the importance of vigilance in clinical practice, encouraging ophthalmologists to explore less common diagnostic possibilities when faced with challenging cases. Further research and clinical investigation are warranted to better understand the mechanisms and potential treatments for amyloidosis affecting the extraocular muscles.

Chronologic Analysis of Tear Dynamics on Blinking Using Quantitative Manometry in Healthy Humans.

PURPOSE: To analyze the tear dynamics during blinking by measuring the inner pressure of the upper lacrimal drainage system. METHODS: This observational study involved 11 healthy bi- or tricenarian volunteers. Direct manometry was performed using a fiber optic pressure sensor inserted into the conjunctival sac, upper/lower canaliculus (5 mm from punctum), and inferior lacrimal sac (15 mm from punctum) during both involuntary and intentional tight blinking. Pressure was measured 200 times/second during 3 separate blinks and then chronologically analyzed. RESULTS: In all subjects of all locations during both types of blinking, the inner pressures during the stationary eyelid closing/opening were positive/approximately zero, while a positive/negative pressure spike was observed during the eyelid closing/opening movement. The averages of the maximum pressure in the spike during the intentional tight blinking (tPmax: mm Hg) in the conjunctival sac, upper/lower canaliculus, and lacrimal sac were 8.00, 12.39/12.93, and 10.59, respectively, while for the minimum (tPmin: mm Hg), the pressures were -3.18, -3.91/-3.43, and -3.31, respectively. The tPmax and tPmin in the lacrimal duct were positively correlated with that of the conjunctival sac, which suggested synchronism of the drainage system. However, the tPmax in the canaliculus was significantly higher than that of the conjunctival sac, which suggested that tears do not flow from the conjunctival sac into the lacrimal duct during eyelid closure. CONCLUSIONS: The upper lacrimal drainage system functions as one united lumen in the lacrimal pump. The positive /negative pressure spike is essential for the lacrimal pump to efficiently eject/aspirate the tear from the lacrimal/conjunctival sac.

Adjustable Medial Epicanthoplasty Using a Rotational Flap for Epiblepharon Repair.

ABSTRACT: This report aimed to introduce the new adjustable rotational skin flap for epicanthoplasty in combination with traditional epiblepharon repair by the modified Hotz procedure. This retrospective study involved 25 consecutive patients with superficial punctate keratitis secondary to epiblepharon complicated with epicanthal fold who underwent the combined surgery between 2019 and 2020. The mean patient age was 11.4 years in this study with a median follow-up was 8months (range, 3-12months). The rationale of the surgery was to release vertical tension of the eyelids by dissecting dense connective tissue beneath the epicanthal fold and to form a new medial canthus using a rotational skin flap supplied by the redundant the upper and/or lower eyelid skin excised during the epiblepharon repair. Postsurgical resolution ofsuperficial punctate keratitis and patient satisfaction was achieved in all patients. Additionally, there were no complications, and no revisional surgery was required in all patients for a median 8 months follow-up period. Utilizing a rotational skin flap during epiblepharon repair is a useful adjunct during epicanthoplasty surgery. This modification is well tolerated and allows for intraoperative adjustment, whereas minimizing scarring and allowing for improved tissue relaxation.

Activation of Mast-Cell-Derived Chymase in the Lacrimal Glands of Patients with IgG4-Related Ophthalmic Disease.

The purpose of this present study was to investigate the distribution and expression of chymase in the lacrimal glands (LGs) of patients afflicted with IgG4-related ophthalmic disease (IgG4-ROD). LGs from patients with severe canalicular obstruction were considered the control group. Toluidine blue staining confirmed a significant increase in the number of mast cells in the LGs obtained from the IgG4-ROD patients. In addition, immunostaining of serial sections from the LGs showed a significant increase in the number of chymase-positive cells and tryptase-positive cells in the IgG4-ROD LGs compared to the normal control LGs. The mRNA expression of chymase, tryptase, TGF-ß1, and collagen-I tended to increase in the IgG4-ROD LGs. Immunostaining of vimentin and α-smooth muscle actin (α-SMA) showed that myofibroblasts were the main cellular components in severely fibrotic regions of LGs in patients with IgG4-ROD. Linear regression analyses on the number of mast cells, chymase-positive cells, and tryptase-positive cells revealed significant positive correlations between those respective cells. Our findings suggest that chymase may play a role in the fibrotic disorder of IgG4-ROD LGs through the regulation of TGF-ß1 activation and collagen-I deposition, and that it may be a therapeutic target for patients afflicted with IgG4-ROD.

Rituximab Monotherapy for Compressive Optic Neuropathy With Giant Ocular Adnexal Mucosa-Associated Lymphoid Tissue lymphoma.

A rare case of compressive optic neuropathy due to giant mucosa-associated lymphoid tissue lymphoma in the orbit was presented. A 87-year-old woman was aware of a slow progressive left ocular proptosis for 10 years and presented after becoming aware of a sudden progression of the proptosis accompanying visual disturbance over the previous 2 months. Orbital imaging and a biopsy of the tumor revealed a mucosa-associated lymphoid tissue lymphoma occupying her left orbit compressing and stretching the left optic nerve. Considering her age and the additional adverse effects of external beam radiation therapy to her damaged optic nerve, rituximab monotherapy was utilized. The intervention resulted in almost complete regression without any serious adverse effect, with left eye best-corrected visual acuity improving from 12/200 to 16/20. Rituximab monotherapy can be one of the first-choice treatment options for mucosa-associated lymphoid tissue lymphoma, especially in cases with the critical damage in the optic nerve.

Roscovitine, a Cyclin-Dependent Kinase-5 Inhibitor, Decreases Phosphorylated Tau Formation and Death of Retinal Ganglion Cells of Rats after Optic Nerve Crush.

Tauopathies are neurodegenerative diseases characterized by abnormal metabolism of misfolded tau proteins and are progressive. Pathological phosphorylation of tau occurs in the retinal ganglion cells (RGCs) after optic nerve injuries. Cyclin-dependent kinase-5 (Cdk5) causes hyperphosphorylation of tau. To determine the roles played by Cdk5 in retinal degeneration, roscovitine, a Cdk5 inhibitor, was injected intravitreally after optic nerve crush (ONC). The neuroprotective effect of roscovitine was determined by the number of Tuj-1-stained RGCs on day 7. The change in the levels of phosphorylated tau, calpain-1, and cleaved α-fodrin was determined by immunoblots on day 3. The expression of P35/P25, a Cdk5 activator, in the RGCs was determined by immunohistochemistry. The results showed that roscovitine reduced the level of phosphorylated tau by 3.5- to 1.6-fold. Calpain-1 (2.1-fold) and cleaved α-fodrin (1.5-fold) were increased on day 3, suggesting that the calpain signaling pathway was activated. P35/P25 was accumulated in the RGCs that were poorly stained by Tuj-1. Calpain inhibition also reduced the increase in phosphorylated tau. The number of RGCs decreased from 2191 ± 178 (sham) to 1216 ± 122 cells/mm2 on day 7, and roscovitine preserved the level at 1622 ± 130 cells/mm2. We conclude that the calpain-mediated activation of Cdk5 is associated with the pathologic phosphorylation of tau.

Two cases of diabetic macular edema complicated by an atypical macular hole.

BACKGROUND: Here we report two patients who developed an atypical macular hole (MH) during the treatment course for diabetic macular edema (DME). CASE PRESENTATIONS: Patient 1 was a 73-year-old male. Optical coherence tomography (OCT) revealed perifoveal retinoschisis (RS) in addition to cystoid macular edema and serous retinal detachment (SRD) in his left eye, and that an MH had developed during the clinical course. A convex surface was formed at the MH margin toward the vitreous cavity, and granular shadows were observed in the fluid cuff. Intraoperative findings revealed a thin epiretinal macular membrane (ERM) around the MH. Patient 2 was a 79-year-old male. Although the patient underwent pars plana vitrectomy (PPV) for proliferative diabetic retinopathy (PDR) in both eyes, RS and a thin ERM in addition to SRD was observed in his left eye after surgery, and an MH developed during the clinical course. As in Patient 1, a convex surface was formed at the fluid cuff margin toward the vitreous cavity. CONCLUSIONS: Both patients had persistent DME, SRD, RS, and a thin ERM before the development of the MH. OCT revealed the formation of a convex surface at the MH margin toward the vitreous cavity, suggesting that the fragility of the layered structure of the retina combined with tangential retinal traction may have been involved in the atypical MH form.

Analysis of Periorbital Soft Tissue in Thyroid Eye Disease.

PURPOSE: To investigate periorbital tissue enlargement in thyroid eye disease (TED) by 3-dimensional CT volumetric analysis. METHODS: Twenty-four adult subjects, 16 with TED and 8 controls, were studied. Three-dimensional volumetric calculations were performed on CT imaging of the orbit and face, focusing on the retroorbicularis oculi fat, suborbicularis oculi fat, facial muscles in periorbital region, orbital fat, extraocular muscles, and orbital volume. Analysis was performed using JMP version 12 software. Each measure was compared between the TED and control groups using Wilcoxon rank sum test. Correlations were investigated between periorbital and orbital tissue using the Spearman's correlation coefficient method. RESULTS: A statistically significant increase in volume was measured in TED patients in the superior and inferior periorbital fat tissue (p = 0.0044, p = 0.047), including the retroorbicularis oculi fat (p = 0.0011), suborbicularis oculi fat (p = 0.0093), and a decrease in facial muscle of superior periorbital region (p = 0.035). Strong positive correlation was noted between the muscles of superior and inferior periorbital region (rs = 0.65; p = 0.0006), and between the suborbicularis oculi fat and retroorbicularis oculi fat (rs = 0.50; p = 0.013). No correlation was observed between orbital and periorbital tissue, except between the orbital fat and the inferior periorbital fat tissue (p = 0.047). CONCLUSIONS: Facial fat in the periorbital region is enlarged in TED, with the superior component correlating with orbital fat tissue expansion. These findings may assist in the clinical evaluation and management of disfigurement in TED patients.Superior and inferior periorbital fat is enlarged in thyroid eye disease with the superior periorbital fat expansion correlating with orbital fat expansion.

Newly Designed Universal Trans-punctal Rigid Lacrimal Microendoscope.

PURPOSE: To report the development and clinical findings of a universal trans-punctal lacrimal microendoscope design. METHODS: In this study, we examined a unique and original "2-bend" (i.e., double-angle) rigid lacrimal microendoscope designed for universal applications for anatomical variations. The shape of endoscope was initially evaluated in 6 lacrimal systems of cadavers (4 Caucasian-cadaver lacrimal systems and 2 Asian-cadaver lacrimal systems). Second, a prospective clinical study involving 45 consecutive cases of nasolacrimal duct obstruction in Japanese patients was conducted to compare the facility and ease of use between the conventional single-bend type and our original 2-bend type trans-punctal lacrimal microendoscope for examination of the lacrimal drainage system. RESULTS: The findings in the cadaver study revealed that original 2-bend lacrimal microendoscope, which was designed double-angled 20°-30° at 10 and 30 mm from the tip of the scope, could more easily used to insert and image all lacrimal systems, while the conventional single-bent lacrimal microendoscope was difficult to insert in subset of patients with a prominent nasal process of the frontal bone. In the clinical trial, our findings showed that 26.7% of lacrimal systems could not be passed using the conventional single-bend design, while using the 2-bend design, all cases could successfully be investigated. CONCLUSIONS: The original 2-bend-design microendoscope was found to be effective and valuable for universal use in examination and evaluation of the lacrimal passage.

Endoscopic Evaluation of Lacrimal Mucosa With Indigo Carmine Stain.

PURPOSE: Histological investigation in the use of indigo carmine for detection of mucosal pathology in lacrimal microendoscopy. To investigate the histopathological correlation of staining found on lacrimal microendoscopy. METHODS: A prospective case series was conducted in patients with a history of nasolacrimal duct obstruction and dacryocystitis requiring treatment with dacryocystorhinostomy or dacryocystectomy. Prior to lacrimal surgery, all patients underwent endolacrimal evaluation using transpunctal lacrimal microendoscopy. Indigo carmine dye (0.2 mg/0.5 ml) was injected into the lacrimal system via the irrigation channel of the endoscope, and after copious irrigation, the differential mucosal staining was recorded. Histopathologic analysis of tissue samples of positively and negatively stained lacrimal sac mucosa collected after surgery was performed to investigate the correlation with the results of each endoscopic evaluation. RESULTS: Four patients underwent dacryocystorhinostomy and 2 patients underwent dacryocystectomy. Histopathology of positive-stained lacrimal sac mucosa corresponded to areas of the advanced fibrous stage of mucosal changes resulting from dacryocystitis, which showed atrophy of epithelium associated with the loss of goblet cells and subepithelium fibrous scarring. In contrast, areas of lacrimal mucosa that did not stain with indigo carmine were still in an active inflammatory stage of dacryocystitis preserving columnar epithelium with goblet cells. CONCLUSIONS: This study suggests that indigo carmine staining is a useful adjunct in lacrimal microendoscopy for accurately detecting areas of highly damaged fibrous lacrimal mucosa, as it allows for direct visualization of lacrimal mucosal pathology and can provide prognostic insight and guidance in regard to treatment options for patients with lacrimal drainage obstruction.Use of indigo carmine dye as an in vivo adjunct in lacrimal microendoscopy is useful for accurately detecting areas of highly damaged lacrimal mucosa.

Impairment of Autophagy Causes Superoxide Formation and Caspase Activation in 661 W Cells, a Cell Line for Cone Photoreceptors, under Hyperglycemic Conditions.

Microvascular changes are the earliest adverse events in diabetic retinopathy, but recent studies have shown that oxidative stress induced by photoreceptors is associated with the development of the retinopathy. The purpose of this study was to determine the roles played by superoxides formed by photoreceptors under hyperglycemic conditions on autophagy. To accomplish this, we cultured 661 W cells, a transformed murine cone cell line, with 5.5 or 25 mM glucose in the presence or absence of 3 methyl adenine (3MA) or rapamycin. The superoxides were determined by flow cytometry using hydroethidine as a fluorescence probe. The autophagy activity was determined by changes in the expression of LC3B2 and P62 by immunoblotting. The degree of mitophagy was determined by the accumulation of mitochondria and lysosomes. Apoptotic changes of 661 W cells were determined by the caspase 3/7 activities. Our results showed higher levels of P62 and superoxides in cells cultured in 25 mM glucose than in 5.5 mM glucose. Addition of 3MA caused a significant increase of P62, superoxides, and caspase 3/7 activities in the 661 W cells cultured in high glucose but not in low glucose. These findings suggest that autophagy is important for the functioning and survival of 661 W cells under hyperglycemic conditions.

Investigation of scleral thermal injuries caused by ultrasonic pars plana phacoemulsification and aspiration using pig eyes.

PURPOSE: The purpose of this study was to investigate the thermal injuries caused by ultrasonic pars plana phacoemulsification and aspiration (PPPEA) using pig eyes. METHOD: Using a 20-gauge (G) vitrectomy system (Accurus®, Fragmatome; Alcon Laboratories) in both the 'open-tip' and 'closed-tip' techniques, PPPEA was performed in pig eyes and the subsequent thermal injuries generated around the scleral wound were measured by infrared thermal imaging (thermography). Post surgery, the state of the scleral wound was observed under a microscope, and a tissue slice containing the scleral wound was then prepared and observed under an optical microscope. RESULTS: Thermography measurements revealed a slight temperature rise around the scleral wound in the open-tip case, yet a marked temperature rise in the closed-tip case. The scleral wound incision produced by the open tip was linear, while that produced by the closed tip was expanded. Histological examination revealed mild degeneration of the sclera around the wound in the open-tip case, yet marked tissue degeneration by thermal injuries in the closed-tip case. CONCLUSION: Our findings showed that in PPPEA, the temperature of the tip of a 20G vitrectomy system rapidly increases due to the closed-tip technique, thus producing obvious thermal damage to the scleral wound. In order to prevent thermal injuries to the scleral wound during PPPEA, it is important to shorten the time of ultrasonic oscillation during surgery as much as possible while the tip is occluded with nuclear fragments.

Orbital fat regeneration following hormonal treatment of metastatic breast carcinoma.

Enophthalmos in the setting of breast cancer metastatic to the orbit results primarily from the disease pathogenesis, or secondary to treatment effects. Orbital volume restoration and fat regeneration following endocrine treatment monotherapy has not been previously reported. A 76- year-old previously healthy female presented with progressive right enophthalmos secondary to metastatic lobular breast carcinoma. Treatment with an aromatase inhibitor (letrozole) resulted in tumor regression and orbital fat restoration with a corresponding improvement in orbital volume and enophthalmos on clinical exam. The patient is alive on continued letrozole with no progressive disease ten years after diagnosis. This case illustrates the resilience of orbital soft tissues and ability of orbital fat to regenerate in face of breast cancer metastasis. We hypothesize that endocrine monotherapy, and avoidance of radiation therapy, allowed for differentiation of remaining orbital stem cells, and facilitated the fat regenerative process.

Case of asteroid hyalosis that developed severely reduced vision after cataract surgery.

BACKGROUND: To report our findings in a patient with asteroid hyalosis (AH) who had a severe reduction of his visual acuity following cataract surgery. The vision was improved by vitreous surgery. CASE PRESENTATION: The patient was an 81-year-old man. Following cataract surgery on his left eye, his decimal best-corrected visual acuity (BCVA) was markedly reduced from 0.2 to 0.02. A large number of asteroid bodies (ABs) was observed to be concentrated on the posterior surface of the implanted intraocular lens. Ultrasound B-mode images showed turbidity of the vitreous that was denser in the anterior vitreous where the ABs were concentrated. During vitrectomy, the ABs were observed to be concentrated in the anterior vitreous cavity, and a complete posterior vitreous detachment (PVD) was present. After vitrectomy successfully removed the ABs, the visibility of the fundus improved and the BCVA recovered to 1.0. CONCLUSION: We suggest that the visual impairment after the cataract surgery was due to the concentrated ABs in the anterior vitreous cavity. The clustering of the ABs in the anterior vitreous cavity was most likely caused by the PVD that developed during the cataract surgery.

Negative impact of AQP-4 channel inhibition on survival of retinal ganglion cells and glutamate metabolism after crushing optic nerve.

The purpose of this study was to determine whether inhibition of aquaporin 4 (AQP4) is neuroprotective or neurodestructive after crushing the optic nerve of rats. The left optic nerves of rats were crushed, and TGN-020 (5.0 mg/kg, crush TGN-020) or its vehicle (DMSO, crush placebo) was injected intraperitoneally just after the crushing. As controls, the left optic nerves were exposed but not touched in other rats (sham controls). The retinal damages were determined by the density of retinal ganglion cells (RGCs) and the ratio of BAX/Bcl-2 on day 7. The glutamate level in the optic nerve on day 1 after the crushing was determined. The expressions of glutamine synthetase, glutamate-aspartate transporter (GLAST), and AQP4 were determined on day 3 by immunoblotting. The effects of AQP4 inhibition on the glutamate-induced changes of AQP4 expression and on the glutamate uptake were determined for optic nerve astrocytes in culture. The results showed that the density of RGCs was 2040 ± 91.3 cells/mm(2) (n = 6) in the sham control, and it was significantly decreased to 1072 ± 134.3 cells/mm(2) after crushing the optic nerve (P < 0.0001, crush placebo, n = 7; Fisher). An intraperitoneal injection of TGN-020 led to a further significant (P = 0.02, Fisher) decrease of the density of RGCs to 743 ± 371 cells/mm(2) (crush TGN-020, n = 7). The mRNA level of BAX/Bcl-2 ratio was 0.37 ± 0.05 in the sham control (n = 6) which was significantly increased to 0.88 ± 0.10 after crushing the optic nerve (placebo crush, n = 7; P = 0.0001, Scheffe). TGN-020 also significantly increased the BAX/Bcl-2 ratio to 1.29 ± 0.4 (n = 6) from the crush placebo group (P = 0.04, Scheffe). Immunoblotting showed similar changes in the protein levels. The glutamate level in the optic nerve was significantly increased to 53.7 ± 6.0 µM/mg/protein on day 1 (n = 4) from the sham control level of 45.9 ± 3.1 µM/mg/protein (n = 4; P = 0.04, t test). TGN-020 significantly (P < 0.05, Scheffe) depressed the expression of glutamate metabolism-related proteins on day 3. Exposure of cultured optic nerve astrocytes to glutamate (1.0 mM, n = 4) significantly increased the expression of AQP4 (P < 0.001, Scheffe) that was depressed by TGN-020 (100 nM, n = 4). In addition, glutamate uptake was inhibited by TGN-020 at 10 nM or higher. These results indicate that an inhibition of AQP4 enhances the loss of RGCs and retinal damages after crushing the optic nerve. Inhibition of AQP4 impairs glutamate metabolism which may account in part for these neurodestructive events.

Effect of rebamipide ophthalmic suspension on the success of lacrimal stent intubation.

PURPOSE: To evaluate the effect of the postoperative administration of rebamipide ophthalmic suspension on the success rate of lacrimal stent intubation (LSI) for the treatment of primary acquired nasolacrimal duct obstruction (PANDO). METHODS: This comparative interventional cohort study investigated 110 consecutive patients with PANDO who were treated with LSI and followed up for 12 months postoperatively at one institution. LSI was performed by one surgeon, and all patients received identical postoperative care. Among the total 110 patients, 71 underwent LSI with postoperative administration of rebamipide ophthalmic suspension, and 39 underwent LSI without administration of the suspension. Data related to patient age, gender, laterality, and postoperative administration of rebamipide ophthalmic suspension were collected and used as independent variables, and logistic regression analyses were performed to compare the anatomical success rate at 12 months postoperatively between patients with and without postoperative administration of the suspension. RESULTS: The anatomical success rate of LSI in patients with and without postoperative administration of rebamipide ophthalmic suspension was 90.1 and 69.2 %, respectively. A comparison of these success rates showed statistical significance, in that the rate of treatment success was higher in PANDO patients who underwent LSI with postoperative administration of the suspension [odds ratio (OR), 3.37; P < 0.05]. CONCLUSIONS: The findings of this study show that postoperative administration of rebamipide ophthalmic suspension increases the rate of anatomical success in patients who undergo LSI for the treatment of PANDO.

Nitric Oxide Increases the Expression of Aquaporin-4 Protein in Rat Optic Nerve Astrocytes through the Cyclic Guanosine Monophosphate/Protein Kinase G Pathway.

AIMS: Nitric oxide (NO) is associated with neuroinflammation in the central nervous system. We determined whether NO increases the expression of aquaporin-4 (AQP4) in optic nerve astrocytes of rats. METHODS: Isolated astrocytes were incubated under normoxic or hypoxic conditions with or without glucose (5.5 mM). The astrocytes were also exposed to different concentrations of S-nitroso-N-acetyl-DL-penicillamine (SNAP, 1.0-100 µM), an NO donor. The expression of AQP4 was determined by Western blot analyses, and NO formation was measured by the Griess reaction. The changes in astrocytic cellular volumes were determined by flow cytometry. RESULTS: Hypoxia and glucose deprivation increased AQP4 expression and NO formation. Inhibition of NO synthetase (NOS) significantly suppressed these changes. SNAP caused a significant increase in AQP4 expression, and the increase was significantly suppressed by carboxy-PTIO, a scavenger of NO. Incubation with 8-Br-cyclic guanosine monophosphate (cGMP) mimicked the effects of SNAP, while the addition of either 1H-[1,2,4]oxadiazolo[4,3,-a]quinoxalin-1-one (ODQ; inhibitor of soluble guanylate cyclase) or KT5823 (protein kinase G inhibitor) suppressed the SNAP-induced increase in AQP4 significantly. SNAP also caused a significant increase in astrocytic cellular volume through the AQP4 channels. CONCLUSIONS: NO increased the AQP4 expression of optic nerve astrocytes through the cGMP/protein kinase G pathway and enlarged their volume.

Measurement of vitreous humor pressure in vivo using an optic fiber pressure sensor.

We conducted a study to assess the pressure difference between the aqueous and vitreous humors in rabbit eyes using a direct intraocular pressure (IOP) measurement method. A micro-optic-fiber pressure sensor was utilized for this purpose. Preliminary experiments with enucleated porcine eyes confirmed the sensor's accuracy in measuring both aqueous and vitreous humor pressure. The main study involved six healthy albino rabbits, where the sensor measured the pressure in the anterior chamber (aIOP) and posterior vitreous-cavity (pIOP). These measurements were compared to aIOP values obtained through rebound tonometry. Additionally, pre- and postoperative pressure comparisons were made after performing a vitrectomy. Results revealed a significant disparity between aqueous and vitreous humor pressures. Prior to vitrectomy, pIOP was 22.8 mmHg, over twice as high as aIOP (11.0 mmHg), but decreased to a similar level following the procedure. Comparison between the sensor measurements and rebound tonometry showed agreement in aIOP values. In conclusion, our study demonstrates that vitreous humor pressure is consistently higher than aqueous humor pressure, reaching the upper limit of normal IOP. Furthermore, vitrectomy effectively reduces pIOP, aligning it with aIOP. These findings contribute valuable insights into intraocular pressure dynamics and have implications for clinical interventions targeting ocular pressure regulation.

A randomized clinical trial of triamcinolone acetonide injection for suppression of inflammation after blepharoptosis surgery.

This study aimed to determine the effectiveness of triamcinolone acetonide in suppressing inflammation after blepharoptosis surgery. The study was designed as prospective, randomized, two medical centers' clinical trial. Thirty-two patients with involutional blepharoptosis of the same degree in both eyelids underwent bilateral transcutaneous levator advancement. At the end of the surgery, 4 mg/0.1 ml of triamcinolone acetonide was injected into a randomly selected upper eyelid. The fellow eyelid was not injected and was used as control. Facial photographs were taken on day 1, week 1, month 1, and month 3, and the degree of inflammation, the margin reflex distance 1 (MRD-1), and levator function (LF) between the two eyelids of each patient were compared. The primary outcome was the selection of the less inflamed eyelid decided by the majority of three individuals unrelated to the study. MRD-1 and LF were analyzed for secondary outcomes. As a result, the injected eyelid was judged to be the less inflamed eyelid in all cases. The MRD-1 in the postoperative period less than 1 month was significantly larger in the injected eyelids than the control eyelids (P<0.03). The postsurgical MRD-1 at month 3, the postsurgical LF at all postsurgical examination times were not statistically different. Adverse complications by the injection, including ptosis, levator dysfunction, increase of the intraocular pressure, and visual disturbance were not observed. In conclusion, a triamcinolone acetonide injection after ptosis surgery is both safe and effective in reducing the early postsurgical inflammation and helpful in an earlier return to a daily routine for the patients.

Change of intraocular blood flow during treatment for thyroid eye disease.

To report a sequential observational study of changes in the retinal and choroidal blood flow during medical and surgical treatments for a thyroid eye disease (TED) patient, using optical coherence tomography angiography (OCTA) and laser speckle flowgraphy (LSFG). A 28-year-old man with a history of Graves' disease diagnosed 8 months prior was presented in the active phase of TED. His clinical activity score (CAS) was 6, but without diplopia or visual loss. Intraocular pressure measurement was OD 20 mmHg and OS 24 mmHg. Thyrotropin receptor antibody (TRAb) and thyroid-stimulating antibody levels were 18.8 IU/L and 4347%. Magnetic resonance imaging revealed enlargement of both extraocular muscles and fat compartments in both orbits. The patient underwent IV pulsed steroid therapy (1 g/day, 3 days) followed by an oral prednisone for 1 month. His CAS score decreased to 4. Bilateral orbital fat decompression decreased his final CAS score to 1 in both eyes. Intraocular blood flow was measured using laser speckle flowgraphy (LSFG), and OCTA was performed. Retinal blood flow increased slightly, but choroidal blood flow showed a robust increase. Choroidal blood flow measured using both LSFG and OCTA was negatively correlated with the CAS score and TRAb. In our case report, the ocular perfusion, especially choroidal blood flow, may decrease in active TED, which may be reversed by medical and surgical treatment.