scholarly journals Effect of peripheral iridectomy on VEGF-A and TGF-β levels in rabbit aqueous humour

2022 ◽  
Vol 22 (1) ◽  
Author(s):  
Annabel C. Y. Chew ◽  
Li-Fong Seet ◽  
Stephanie W. L. Chu ◽  
Nyein C. Lwin ◽  
Tina T. Wong
Keyword(s):  
Anterior Chamber ◽  
Aqueous Humour ◽  
Glaucoma Surgery ◽  
Filtration Surgery ◽  
Glaucoma Filtration Surgery ◽  
Peripheral Iridectomy ◽  
New Zealand White Rabbits ◽  
The Right ◽  
Tgf Β1 ◽  
Time Point

Abstract Background Peripheral iridectomy (PI), routinely performed during glaucoma filtration surgery, may contribute to scarring. This study aims to determine whether PI alters the concentrations of VEGF-A and TGF-β isoforms in the rabbit aqueous humour. Methods Anterior chamber paracentesis (ACP) was performed in both eyes of six New Zealand white rabbits, with additional surgical PI performed in the right eyes. Eyes were examined on postoperative days (PODs) 1, 7, 30 and 60 by means of the tonopen, slit-lamp biomicroscopy, and bead-based cytokine assays for TGF-β and VEGF-A concentrations in the aqueous humor. Results ACP caused a significant reduction in intraocular pressure (IOP) from mean preoperative 11.47 ± 1.01 mmHg to 5.67 ± 1.63 mmHg on POD 1 while PI did not cause further IOP reduction. Limbal conjunctival vasculature appeared slightly increased on POD 1 in both ACP and PI eyes with PI also causing mild bleeding from damaged iris vessels. Two PI eyes developed fibrinous anterior chamber reaction and/ or peripheral anterior synechiae. Aqueous VEGF-A levels were not significantly different between eyes treated with ACP and PI. Aqueous TGF-β concentrations distributed in the ratio of 4:800:1 for TGF-β1:TGF-β2:TGF-β3 respectively. While aqueous TGF-β2 was not significantly induced by either procedure at any time point, TGF-β1 and TGF-β3 were significantly induced above baseline levels by PI on POD 1. Conclusion PI increases the risk of inflammation. The combined induction of aqueous TGF-β1 and TGF-β3 by PI in glaucoma surgery may impact surgery success in glaucoma subtypes sensitive to these isoforms.

scholarly journals Ex-PRESS shunt implantation for intractable glaucoma with posterior chamber phakic intraocular lens: a case report

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Rongrong Hu ◽  
Wei Xu ◽  
Baishuang Huang ◽  
Xiaoyu Wang
Keyword(s):  
Anterior Chamber ◽  
Intraocular Lens ◽  
High Myopia ◽  
Posterior Chamber ◽  
Filtration Surgery ◽  
Phakic Intraocular Lens ◽  
Glaucoma Filtration Surgery ◽  
Shallow Anterior Chamber ◽  
The Right ◽  
Intractable Glaucoma

Abstract Background Implantation of the posterior chamber phakic intraocular lens has been widely performed to correct high and extreme myopia. Chronic intraocular pressure (IOP) elevation may occur in its late postoperative period. For medically uncontrolled cases, surgical treatment is necessary, and benefits should be weighed against risks when determining whether to remove the lens. Case presentation A 32-year-old man with extremely high myopia presented with progressive blurred vision and medically uncontrolled IOP in the right eye. His past ocular history was significant for bilateral implantable collamer lens (ICL) implantation ten years ago. On ophthalmic examination, the ICL was well placed with a vault height of 456 µm in the right eye. The anterior chamber angles were open but narrow, and mild to moderate trabecular pigmentation was noted. Ex-PRESS glaucoma filtration surgery without ICL removal was performed to control IOP. During surgery, an Ex-PRESS P50 shunt was inserted into the anterior chamber via the front edge of the blue-grey transition zone between the sclera and cornea. Transient hypotony and shallow anterior chamber occurred in the first week after surgery, along with an ICL tilt towards the cornea with reduced vault height. No other complications related to either the ICL or the Ex-PRESS shunt were noted. IOP remained stable at 12 ~ 14 mmHg at the first 3-month follow-up. Conclusions Ex-PRESS glaucoma filtration surgery might be a safe and effective alternative treatment for intractable glaucoma with high myopia and ICL implantation. Careful assessment of the ICL position and anterior chamber angle is necessary to plan the appropriate surgical procedure. A postoperative shallow anterior chamber may result in ICL dislocation.

scholarly journals Conventional glaucoma implants and the new MIGS devices: a comprehensive review of current options and future directions

Eye ◽  
2021 ◽  
Author(s):  
Inês C. F. Pereira ◽  
Rosanne van de Wijdeven ◽  
Hans M. Wyss ◽  
Henny J. M. Beckers ◽  
Jaap M. J. den Toonder
Keyword(s):  
Anterior Chamber ◽  
Aqueous Humour ◽  
Alternative Pathway ◽  
Glaucoma Surgery ◽  
Future Directions ◽  
Plate Design ◽  
Glaucoma Drainage Devices ◽  
Abnormal Increase ◽  
Preventable Blindness ◽  
Glaucoma Implants

AbstractGlaucoma is a progressive optic neuropathy that is the second leading cause of preventable blindness worldwide, after cataract formation. A rise in the intraocular pressure (IOP) is considered to be a major risk factor for glaucoma and is associated with an abnormal increase of resistance to aqueous humour outflow from the anterior chamber. Glaucoma drainage devices have been developed to provide an alternative pathway through which aqueous humour can effectively exit the anterior chamber, thereby reducing IOP. These devices include the traditional aqueous shunts with tube-plate design, as well as more recent implants, such as the trabeculectomy-modifying EX-PRESS® implant and the new minimally invasive glaucoma surgery (MIGS) devices. In this review, we will describe each implant in detail, focusing on their efficacy in reducing IOP and safety profile. Additionally, a critical and evidence-based comparison between these implants will be provided. Finally, we will propose potential developments that may help to improve the performance of current devices.

Corneal Complications

2013 ◽  
Author(s):  
Clark L. Springs
Keyword(s):  
Dna Synthesis ◽  
Intraepithelial Neoplasia ◽  
Glaucoma Surgery ◽  
Filtration Surgery ◽  
Proliferating Cells ◽  
Glaucoma Filtration Surgery ◽  
Normal Tissues ◽  
Corneal Haze ◽  
Vascular Proliferation ◽  
Pterygium Surgery

The desired effects of antifibrotic agents 5-fluorouracil (5-FU) and mitomycin-C (MMC) in glaucoma filtration surgery result from their ability to limit postoperative scarring by inhibiting vascular proliferation and fibroblastic transformation. However, these same mechanisms of action can have deleterious effects on surrounding normal tissues such as the cornea. Knowing how to use these agents is important in preventing antifibrotic-related complications. 5-FU is an inhibitor of DNA synthesis, specifically thymidylate synthetase, and blocks thymidine from being incorporated into DNA. In addition to affecting DNA synthesis, 5-FU also may be incorporated into RNA, interfering with RNA synthesis and therefore protein synthesis. Thus, it is more toxic to actively proliferating cells. In glaucoma filtration surgery, 5-FU is generally administered intraoperatively (50 mg/mL for 5 minutes). 5-FU can also be administered as a subconjunctival injection postoperatively with a dosage of 5.0–7.5 mg in 0.1–0.15 mL solution directly from the 50 mg/mL bottle. A series of injections may be given over several weeks and titrated based on clinical response. In addition to glaucoma filtration surgery, 5-FU has also been used for other ophthalmic applications such as pterygium surgery, lacrimal surgery, and during vitrectomy to prevent proliferative vitreoretinopathy. MMC is an alkylating agent that crosslinks DNA. It requires enzymatic activation via cytochrome p450 prior to exerting its inhibitory effects on DNA synthesis. MMC activity is independent of cell cycle and affects both actively replicating and nonreplicating cells. However, variations in enzymatic activity among individuals may contribute to the differences in efficacy, as well as toxicity of MMC. In glaucoma filtration surgery, MMC is typically administered as a single intraoperative application. It is applied after dissection of the conjunctival flap and prior to the formation of the scleral flap. Most surgeons use a dose of 0.1–0.5 mg/mL with an exposure time of 1–5 minutes depending upon the clinical indication. MMC use has also been well established for refractive surgery to prevent corneal haze after photorefractive keratectomy in patients at high risk of developing corneal haze, pterygium surgery, and corneal intraepithelial neoplasia. For more information on 5-FU and MMC in glaucoma surgery, see Chapter 3.

scholarly journals Angle stability and outflow in excisional ab interno trabeculectomy with active versus passive chamber management

2017 ◽  
Author(s):  
Chao Wang ◽  
Yalong Dang ◽  
Susannah Waxman ◽  
Xiaobo Xia ◽  
Robert N Weinreb ◽  
...  
Keyword(s):  
Anterior Chamber ◽  
Anterior Segment ◽  
Anterior Chamber Depth ◽  
Glaucoma Surgery ◽  
Training Model ◽  
Training System ◽  
Angle Stability ◽  
Ab Interno Trabeculectomy ◽  
The Right ◽  
Ab Interno

Purpose: To compare the intraoperative angle stability and the postoperative outflow of two ab interno trabeculectomy devices that excise the trabecular meshwork. The newer device has an active aspiration and irrigation port while the older requires viscoelastic to maintain the anterior chamber. We hypothesized that anterior segment optical coherence tomography (ASOCT) allows quantifying the intraoperative behavior in a microincisional glaucoma surgery (MIGS) pig eye training model. Methods: Twelve freshly enucleated porcine eyes were measured with ASOCT at baseline, at the beginning of the procedure and at its conclusion to determine the anterior chamber depth (ACD) and the nasal angle in degrees. The right and left eye of pairs were randomly assigned 24 to an active dual blade goniectome (aDBG) and a passive dual blade goniectome (pDBG) group, 25 respectively. The aDBG had an irrigation and aspiration port while the pDBG required surgery 26 under viscoelastic. We performed the procedures using our MIGS training system with a 27 standard, motorized ophthalmic operating microscope. We estimated outflow by obtaining 28 canalograms with fluorescent spheres. Results: In aDBG, the nasal angle remained wide open during the procedure at above 90° and 30 did not change towards the end (100±10%, p=0.9). In contrast, in pDBG, ACD decreased by 31 51±19% to 21% below baseline (p<0.01) while the angle progressively narrowed by 40±12% 32 (p<0.001). Canalograms showed a similar extent of access to the outflow tract with the aDBG 33 and the pDBG (p=0.513). The average increase for the aDBG in the superonasal and inferonasal 34 quadrants was between 27 to 31% and for the pDBG between 15 to 18%. Conclusion: ASOCT demonstrated that active irrigation and aspiration improved anterior 36 chamber maintenance and ease of handling with the aDBG in this MIGS training model. The 37 immediate postoperative outflow was equally good with both devices.

Effects of Membrane Adhesion Barriers on Wound Healing Reaction after Glaucoma Filtration Surgery: A Comparative Study with Interceed and Seprafilm

2005 ◽  
Vol 15 (5) ◽  
pp. 591-597 ◽  
Author(s):  
N. Akyol ◽  
S. Aydogan ◽  
N. Akpolat
Keyword(s):  
Wound Healing ◽  
Anterior Chamber ◽  
Anterior Chamber Depth ◽  
Fistula Tract ◽  
Filtration Surgery ◽  
Glaucoma Filtration Surgery ◽  
Cell Counts ◽  
Significant Difference ◽  
Hematoxylin And Eosin ◽  
Group 1

Purpose To evaluate and compare the effectiveness of two adhesion barriers, Interceed and Seprafilm, on wound healing reaction after glaucoma filtration surgery. Materials and Methods Full-thickness filtration surgery was carried out on three groups, each containing four rabbits. Interceed and Seprafilm prepared in 3×4 mm dimensions was put on and around scleral opening in Groups 1 and 2, respectively. All groups received tobramycin and dexamethasone drops tid for 14 days. Intraocular pressure (IOP), anterior chamber depth, and bleb appearance were checked on the first, third, seventh, and 14th days. The rabbits were killed on the 14th day and the trabeculectomy area with overlying conjunctiva was excised. The samples were fixed with 10% formalin, buried in paraffin, and stained with hematoxylin and eosin. The surgical site and surrounding subconjunctival area were evaluated histopathologically for cell counts (fibroblast, lymphocyte, eosinophil, and macrophage), presence of edema and foreign body reaction, and potency of the fistula tract. Results Mean IOP at the first and third day examinations was significantly different between groups, but there was no statistically significant difference among the groups with respect to IOP, anterior chamber depth, or bleb appearance at the seventh and 14th days. The groups were similar with respect to number of fibroblasts, eosinophils, and neutrophils. Number of macrophages was significantly increased in Groups 1 and 2 and number of vessels was significantly decreased in Group 1. Conclusions Neither of these two adhesion-preventing substances seems to suppress wound healing reaction after glaucoma filtration surgery. However, a diminished wound healing reaction was expected with a decreased number of vessels, such as in Group 1. Increased number of macrophages in both groups may result in a decreased level of some inflammatory mediators.

scholarly journals AR12286 Alleviates TGF-β-Related Myofibroblast Transdifferentiation and Reduces Fibrosis after Glaucoma Filtration Surgery

Molecules ◽  
2020 ◽  
Vol 25 (19) ◽  
pp. 4422
Author(s):  
Wen-Sheng Cheng ◽  
Ching-Long Chen ◽  
Jiann-Torng Chen ◽  
Le-Tien Lin ◽  
Shu-I Pao ◽  
...  
Keyword(s):  
Cell Migration ◽  
Intraocular Pressure ◽  
Kinase Inhibitor ◽  
Control Group ◽  
Filtration Surgery ◽  
Glaucoma Filtration Surgery ◽  
Collagen Contraction ◽  
Β Receptor ◽  
Tgf Β1

Scar formation can cause the failure of glaucoma filtration surgery. We investigated the effect of AR12286, a selective Rho-associated kinase inhibitor, on myofibroblast transdifferentiation and intraocular pressure assessment in rabbit glaucoma filtration surgery models. Cell migration and collagen contraction were used to demonstrate the functionality of AR12286-modulated human conjunctival fibroblasts (HConFs). Polymerase chain reaction quantitative analysis was used to determine the effect of AR12286 on the production of collagen Type 1A1 and fibronectin 1. Cell migration and collagen contraction in HConFs were activated by TGF-β1. However, compared with the control group, rabbit models treated with AR12286 exhibited higher reduction in intraocular pressure after filtration surgery, and decreased collagen levels at the wound site in vivo. Therefore, increased α-SMA expression in HConFs induced by TGF-β1 could be inhibited by AR12286, and the production of Type 1A1 collagen and fibronectin 1 in TGF-β1-treated HConFs was inhibited by AR12286. Overall, the stimulation of HConFs by TGF-β1 was alleviated by AR12286, and this effect was mediated by the downregulation of TGF-β receptor-related SMAD signaling pathways. In vivo results indicated that AR12286 thus improves the outcome of filtration surgery as a result of its antifibrotic action in the bleb tissue because AR12286 inhibited the TGF-β receptor-related signaling pathway, suppressing several downstream reactions in myofibroblast transdifferentiation.

scholarly journals Angle stability and outflow in excisional ab interno trabeculectomy with active versus passive chamber management

2017 ◽  
Author(s):  
Chao Wang ◽  
Yalong Dang ◽  
Susannah Waxman ◽  
Xiaobo Xia ◽  
Robert N Weinreb ◽  
...  
Keyword(s):  
Anterior Chamber ◽  
Anterior Segment ◽  
Anterior Chamber Depth ◽  
Glaucoma Surgery ◽  
Training Model ◽  
Training System ◽  
Angle Stability ◽  
Ab Interno Trabeculectomy ◽  
The Right ◽  
Ab Interno

Purpose: To compare the intraoperative angle stability and the postoperative outflow of two ab interno trabeculectomy devices that excise the trabecular meshwork. The newer device has an active aspiration and irrigation port while the older requires viscoelastic to maintain the anterior chamber. We hypothesized that anterior segment optical coherence tomography (ASOCT) allows quantifying the intraoperative behavior in a microincisional glaucoma surgery (MIGS) pig eye training model. Methods: Twelve freshly enucleated porcine eyes were measured with ASOCT at baseline, at the beginning of the procedure and at its conclusion to determine the anterior chamber depth (ACD) and the nasal angle in degrees. The right and left eye of pairs were randomly assigned 24 to an active dual blade goniectome (aDBG) and a passive dual blade goniectome (pDBG) group, 25 respectively. The aDBG had an irrigation and aspiration port while the pDBG required surgery 26 under viscoelastic. We performed the procedures using our MIGS training system with a 27 standard, motorized ophthalmic operating microscope. We estimated outflow by obtaining 28 canalograms with fluorescent spheres. Results: In aDBG, the nasal angle remained wide open during the procedure at above 90° and 30 did not change towards the end (100±10%, p=0.9). In contrast, in pDBG, ACD decreased by 31 51±19% to 21% below baseline (p<0.01) while the angle progressively narrowed by 40±12% 32 (p<0.001). Canalograms showed a similar extent of access to the outflow tract with the aDBG 33 and the pDBG (p=0.513). The average increase for the aDBG in the superonasal and inferonasal 34 quadrants was between 27 to 31% and for the pDBG between 15 to 18%. Conclusion: ASOCT demonstrated that active irrigation and aspiration improved anterior 36 chamber maintenance and ease of handling with the aDBG in this MIGS training model. The 37 immediate postoperative outflow was equally good with both devices.

Microspheres scar formation glaucoma filtration surgery area therapeutic effect—Based on rapamycin-chitosan-calcium alginate sustained-release

2020 ◽  
Vol 10 (6) ◽  
pp. 848-855
Author(s):  
Shasha Wang ◽  
Feiping Xu ◽  
Jie He ◽  
Tingyi Cao ◽  
Rui Liu ◽  
...  
Keyword(s):  
Intraocular Pressure ◽  
Sustained Release ◽  
Release Rate ◽  
Calcium Alginate ◽  
Filtration Surgery ◽  
Glaucoma Filtration Surgery ◽  
Group A ◽  
Group B ◽  
The Right ◽  
Sustained Release Microspheres

To study the efficacy of rapamycin (RAPA)-chitosan (CS)-calcium alginate (CA) sustained-release microspheres on scar formation in a rabbit model of glaucoma filtration surgery. Eighty New Zealand white rabbits were randomly divided into four groups and a glaucoma filtration model was established by scleral bite through the eyes. RAPA-CS-CA sustained-release microspheres were implanted in the right eye of 40 rabbits (Group A) and CS blank sustained-release microspheres were implanted in the left eye (Group B). Another 40 rabbits were treated with a 0.2 g·L-1 RAPA cotton sheet in the right eye (Group C) and the left eye underwent a simple sclerotomy (Group D). The intraocular pressure, filter bleb, anterior chamber inflammation, complications, and corneal endothelial cell density were observed after the operation. Rabbits were euthanized for pathological examination 7 days, 14 days, and 21 days after the operation. The drug loading rate of RAPA-CS-CA sustainedrelease microspheres was (34.58±1.47)% and the encapsulation rate was (56.23±1.55)%. The microsphere release in vitro was relatively stable. The release rate of the microspheres during the burst was only 16.54%. After 49 days, the cumulative release rate of the microspheres reached 94.07% and the sustained release effect was significant within 45 days. Group A maintained low-level intraocular pressure for the longest period of time, followed by Group C, and then Group B and D. The survival time of filter vesicles in Group A was longer than that in other groups. There were no postoperative complications in each group. The conjunctival epithelium of Group A had better integrity and fewer subconjunctival fibroblasts than other groups. There was no obvious inflammation or infiltration around the filtering mouth and there were fewer new collagen fibers. RAPA-CS-CA slow-release microspheres safely and effectively inhibited the proliferation of fibroblasts and neonatal collagen fibers in rabbit glaucoma filtration surgery and significantly improved the success rate of glaucoma filtration surgery.

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