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Shan C Lin - One of the best experts on this subject based on the ideXlab platform.

  • ocular gossypiboma ultrasound b scan assessment of retained surgical sponge after Ahmed Valve surgery
    Journal of Glaucoma, 2017
    Co-Authors: Kelly Babic, Christine Siguanbell, Michael Hee, Shan C Lin
    Abstract:

    PURPOSE OF THE STUDY To present the first documented case of an ocular gossypiboma (retained foreign body) of a mitomycin-C-soaked sponge confirmed echographically using diagnostic ultrasound B-scan after Ahmed Valve surgery. PATIENTS AND METHODS A patient who underwent phacoemulsification with Ahmed Valve implantation surgery had a retained Weck-Cels sponge soaked with mitomycin-C. With the use of ocular ultrasound B-scan, the retained sponge was localized and a second procedure was performed to explant it. CONCLUSION In cases of ocular gossypiboma the use of ultrasound modalities can be a valuable tool especially because B-scan access is common and can be cost-effective.

  • ocular gossypiboma ultrasound b scan assessment of retained surgical sponge after Ahmed Valve surgery a case report
    Journal of Glaucoma, 2017
    Co-Authors: Kelly Babic, Christine Siguanbell, Michael Hee, Shan C Lin
    Abstract:

    PURPOSE OF THE STUDY To present the first documented case of an ocular gossypiboma (retained foreign body) of a mitomycin-C-soaked sponge confirmed echographically using diagnostic ultrasound B-scan after Ahmed Valve surgery. PATIENTS AND METHODS A patient who underwent phacoemulsification with Ahmed Valve implantation surgery had a retained Weck-Cels sponge soaked with mitomycin-C. With the use of ocular ultrasound B-scan, the retained sponge was localized and a second procedure was performed to explant it. CONCLUSION In cases of ocular gossypiboma the use of ultrasound modalities can be a valuable tool especially because B-scan access is common and can be cost-effective.

  • A role for antimetabolites in glaucoma tube surgery: current evidence and future directions.
    Current opinion in ophthalmology, 2016
    Co-Authors: Behzad Amoozgar, Shan C Lin, Ying Han, Jane Kuo
    Abstract:

    PURPOSE OF REVIEW Glaucoma is the leading cause of irreversible blindness worldwide. The main treatment modality for glaucoma is the reduction and control of the intraocular pressure (IOP). Glaucoma filtration surgery, including trabeculectomy and/or implantation of a glaucoma drainage device (GDD), is warranted if IOP remains medically uncontrolled. However, postoperative scarring remains a critical determinant of long-term bleb survival and IOP control after drainage surgery. Antimetabolites, such as mitomycin C and 5-fluorouracil, have been used for many years to increase survival time of filtration surgeries by preventing bleb fibrosis and scarring. The aim of this study is to provide an overview of: the current usage of these antimetabolites in GDD, the recent advancements of these antimetabolites in combination with other technologies, and the role of future antimetabolites. RECENT FINDINGS Mitomycin C and 5-fluorouracil have been used in GDD and trabeculectomy to prevent the exaggerated cellular reaction that leads to fibrosis. The adjunctive administration of these drugs intraoperatively and postoperatively has resulted in a lower rate of the hypertensive phase, and possibly a better long-term success rate in Ahmed Valve surgeries. However, the application of these antimetabolites and their multiple-dosing applications are associated with nonspecific cytotoxicity and potentially severe complications such as bleb leak and conjunctival erosion over the tube. Recent studies are thus focusing on different medications, targeting new molecular pathways, and designing new delivery vehicles to minimize current antimetabolites side-effects and increase their efficacy. Promising results of these studies have led to development of new collaborative medications and advanced drug delivery systems for better modulation of GDD surgeries' predictable outcomes. SUMMARY The development of small molecule therapeutics, combination therapies, and innovative drug vehicles to prevent postsurgical fibrosis and achieve better surgical outcome in glaucoma filtration surgeries is promising.

  • intravitreal ranibizumab as an adjunct for Ahmed Valve surgery in open angle glaucoma a pilot study
    Clinical and Experimental Ophthalmology, 2013
    Co-Authors: Rajen U Desai, Kuldev Singh, Shan C Lin
    Abstract:

    Background:  To determine the safety and efficacy of intravitreal ranibizumab therapy before and after Ahmed tube insertion for open-angle glaucoma as a means of optimizing postoperative intraocular pressure control. Design:  Randomized, controlled trial. Participants:  Open-angle glaucoma patients scheduled for Ahmed tube insertion, randomized to ranibizumab or control groups. Methods:  Ranibizumab (0.5 mg in 0.05 mL) was administered intravitreally at three time points: 9 days prior to surgery, 1 month post-surgery and 2 months post-surgery. Control patients underwent the same procedure without ranibizumab. Main Outcome Measure:  Success at 6 months postoperatively was defined as intraocular pressure <18 mmHg with no adjunctive medications or intraocular pressure <15 mmHg with one adjunctive medication. Results:  The study and control arms included six and five subjects, respectively, with four in each arm undergoing combined cataract surgery. In the ranibizumab arm, the preoperative and postoperative intraocular pressure/medication usage was 21.0 ± 6.7 mmHg on 3.2 ± 1.5 medications and 14.7 ± 1.9 mmHg on 0.5 ± 0.8 medications, respectively. In the control arm, preoperative and postoperative intraocular pressure/medication usage was 18.8 ± 3.8 mmHg on 2.8 ± 1.3 medications and 16.2 ± 3.6 mmHg with 1.8 ± 1.6 medications, respectively. Success was achieved in 83% of subjects in the ranibizumab group compared with 40% in the control group (two-tailed Fisher's exact test, P = 0.24). Conclusion:  The findings from this small pilot comparative study suggest that intravitreal ranibizumab use may be a safe and potentially effective adjunctive treatment modality in improving success after Ahmed tube placement.

Arif O. Khan - One of the best experts on this subject based on the ideXlab platform.

  • two year survival of Ahmed Valve implantation in the first 2 years of life with and without intraoperative mitomycin c
    Ophthalmology, 2009
    Co-Authors: Faisal Almobarak, Arif O. Khan
    Abstract:

    Purpose To evaluate the effect of intraoperative mitomycin-C (MMC) on polypropylene Ahmed glaucoma Valve (AGV) survival 2 years after implantation during the first 2 years of life. Design Retrospective institutional comparative series (1995–2005). Participants Thirty-one eyes of 27 patients (23 unilateral, 4 bilateral; 16 boys, 11 girls) undergoing AGV implantation at a mean age of 11.1 months (standard deviation [SD], 5.46), all of which had 2 years of regular postoperative follow-up. MMC was applied intraoperatively in those cases in the area of AGV implantation in 16 (52%) and was not applied in 15 (48%). In some eyes, MMC was applied intraoperatively in cases done by the surgeons who routinely used MMC for all AGV implantation in young children. Methods Failure was defined as intraocular pressure (IOP) > 22 mmHg with or without glaucoma medications, the need for an additional procedure for IOP control, or the occurrence of significant complications (e.g., endophthalmitis, retinal detachment, persistent hypotony [IOP Main Outcome Measures Failure or significant complications as defined. Results Mean survival for the non-MMC eyes (22.15 months; standard error [SE], 1.93) was significantly longer than survival for the MMC eyes (16.25 months; SE, 2.17) by the log-rank test ( P = 0.025). The difference in cumulative survival at 2 years was also significantly different by log-rank test ( P = 0.001): 80.0% (SE 10.3) and 31.3% (SE 11.6), respectively. Conclusions Rather than improved survival, intraoperative use of MMC was associated with shorter survival 2 years after AGV implantation during the first 2 years of life. We speculate that MMC-induced tissue death can stimulate a reactive fibrosis around the AGV in very young eyes. Financial Disclosure(s) The authors have no proprietary or commercial interest in any of the materials discussed in this article.

  • complications and 2 year Valve survival following Ahmed Valve implantation during the first 2 years of life
    British Journal of Ophthalmology, 2009
    Co-Authors: Faisal Almobarak, Arif O. Khan
    Abstract:

    Aim: To report complications and 2-year Valve survival following Ahmed Valve implantation during the first 2 years of life. Methods: Retrospective institutional case series. Results: Forty-two eyes of 36 patients with Ahmed Valve implantation (without prior drainage device surgery) during the first 2 years of life and 2 years’ postsurgical follow-up were identified. Most eyes had primary congenital glaucoma (28/42, 66.7%), aphakic glaucoma (5/42, 11.9%) or Peters anomaly (5/42, 11.9%). All but three eyes had prior ocular surgery. Surgery was at a mean age of 11.83 months (m) (SD 5.63). The most common significant postoperative complications were tube malpositioning requiring intervention (11/42, 26.2%), endophthalmitis (3/42, 7.1%; one with tube exposure) and retinal detachment (3/42, 7.1%). Thirty-six eyes (85.8%) required resumption of antiglaucoma medications to maintain intraocular pressure (IOP) ⩽22 mm Hg a mean of 7.2 m (SD 6.8) postoperatively. Cumulative probabilities of Valve survival (IOP⩽22 mm Hg with or without medication) by Kaplan–Meier analysis were 73.8% and 63.3% at 12 months and 24 months, respectively. Conclusions: Postoperative tube malpositioning that required surgical revision was common in this age group. Infectious endophthalmitis and retinal detachment are known potential complications following any incisional surgery for advanced buphthalmos; however, tube exposure is a unique potential problem following aqueous shunt implantation that can lead to intraocular infection. Cumulative Valve survival 2 years following implantation was 63.3%.

Chan Yun Kim - One of the best experts on this subject based on the ideXlab platform.

  • long term clinical outcomes of Ahmed Valve implantation in patients with refractory glaucoma
    PLOS ONE, 2017
    Co-Authors: Chang Kyu Lee, Kyoung Tak, Young Jae Hong, Chan Yun Kim
    Abstract:

    Purpose To evaluate the long-term efficacy of intraocular pressure (IOP) reduction and complications of Ahmed Glaucoma Valve (AGV) implantation in patients with refractory glaucoma. Design Retrospective study. Subjects The study involved 302 refractory glaucoma patients who underwent AGV implantation and had a minimum follow-up of 6 months between March 1995 and December 2013. Methods An operation was defined as successful when (1) the postoperative IOP remained between 5 and 21 mmHg and was reduced 30% compared to the baseline IOP with or without medication, (2) there was no loss of light perception or vision-threatening severe complications, and (3) no additional filtering or aqueous drainage surgery was required. Clinical records were reviewed. Main outcome measures IOP, anti-glaucoma medications, and complications Results The mean follow-up period was 62.25 months (range, 6 to 190 months). The cumulative probability of success was 89% at 6 months, 81% at 1 year, 66% at 3 years, 44% at 10 years, and 26% at 15 years. IOP was reduced from a mean of 32.2 ± 10.5 mmHg to 18.6 ± 9.1 mmHg at 1 month, 15.2 ± 7.0 mmHg at 6 months, and 14.2 ± 3.5 mmHg at 15 years. Surgical failures were significantly increased when preoperative IOP was high, and when severe complications occurred after AGV implantation (P < 0.05). Conclusion AGV implantation was successful for IOP control in patients with refractive glaucoma in the long term. However, the success rate of surgery decreased over time. Preoperative high IOP and severe complications related to the operation were significant risk factors for failure.

  • Risk factors for surgical failure in patients with refractory glaucoma who underwent Ahmed Valve implantation, and results from Cox proportional hazard regression models.
    2017
    Co-Authors: Chang Kyu Lee, Kyoung Tak, Young Jae Hong, Chan Yun Kim
    Abstract:

    Risk factors for surgical failure in patients with refractory glaucoma who underwent Ahmed Valve implantation, and results from Cox proportional hazard regression models.

  • bleb analysis and short term results of biodegradable collagen matrix augmented Ahmed glaucoma Valve implantation 6 month follow up
    Investigative Ophthalmology & Visual Science, 2015
    Co-Authors: Seungsoo Rho, Kyoung Tak, Youngje Sung, Sae Heun Rho, Chan Yun Kim
    Abstract:

    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.

  • surgical results of Ahmed Valve implantation with intraoperative bevacizumab injection in patients with neovascular glaucoma
    Journal of Glaucoma, 2012
    Co-Authors: Kyoung Tak, Samin Hong, Gong Je Seong, Jong Yun Yang, Ji Hyun Kim, Na Rae Kim, Eun Suk Lee, Chan Yun Kim
    Abstract:

    PURPOSE To investigate the surgical results of Ahmed Valve implantation with intraoperative bevacizumab injection in patients with neovascular glaucoma (NVG). METHODS A retrospective comparative case series review was conducted on 52 eyes with NVG who underwent Ahmed glaucoma Valve implantation with or without intraoperative bevacizumab intravitreal injection. In the intraoperative intravitreous bevacizumab injection group (IVB group, 20 eyes), 1.25 mg of bevacizumab was injected into the vitreous cavity during Ahmed Valve implantation. In the control group (32 eyes), only Ahmed Valve implantation was performed. Surgical failure was defined when (1) the postoperative intraocular pressure was over 21 mm Hg at consecutive clinic visits, (2) the visual acuity became light perception negative, (3) additional antiglaucomatic surgery was required, or (4) devastating operative or postoperative complications were noted. RESULTS Although the success rate in the IVB group (70.0%) was higher than that in the control group (62.5%) 1 year after operation, the differences were not statistically significant (P=0.828 by log-rank test). Mean intraocular pressures in the IVB group were significantly lower than those of the control group at 12 and 15 months (P<0.05 by the Mann-Whitney U test). Postoperative complications were similar between the 2 groups. Preoperative history of trabeculectomy was a significant risk factor for surgical failure of Ahmed Valve implantation in NVG (relative risk=4.618; P=0.018 by Cox regression model). CONCLUSIONS Intraoperative IVB injection does not seem to be helpful for better surgical outcomes of Ahmed Valve implantation in NVG. A history of trabeculectomy is a risk factor for failure after Ahmed Valve implantation in patients with NVG.

  • level of vascular endothelial growth factor in aqueous humor and surgical results of Ahmed glaucoma Valve implantation in patients with neovascular glaucoma
    Journal of Glaucoma, 2009
    Co-Authors: Yong Guk Kim, Samin Hong, Christopher Seungkyu Lee, Sung Yong Kang, Gong Je Seong, Kyoung Tak, Chan Yun Kim
    Abstract:

    Purpose To determine the associations between the levels of growth factors in aqueous humor and the surgical outcomes of Ahmed glaucoma Valve implantation in patients with neovascular glaucoma (NVG). Methods From 19 NVG eyes of 19 patients, a sample of aqueous humor was taken just before Ahmed glaucoma Valve implantation. Levels of vascular endothelial growth factor (VEGF), transforming growth factor (TGF)-beta1, and TGF-beta2 in aqueous humor aspirates were measured using a sandwich enzyme-linked immunosorbent assay method. When the postoperative intraocular pressures were >or=21 mm Hg with or without antiglaucoma medications at 2 successive visits or when any other surgical interventions were needed to lower intraocular pressure, that surgery was considered a failure. After patients were classified into success versus failure groups, the levels of the growth factors between the 2 groups was compared. The cumulative probability of success according to Kaplan-Meier analysis was also determined. Results Mean postoperative follow-up period was 40.9+/-19.6 months and cumulative probability of success was 43% at 57 months after surgery. Mean VEGF level in the failure group was higher than that of the success group (P=0.014). However, there was no statistical difference in the levels of TGF-beta1, TGF-beta2, and protein between 2 study groups (all P>0.05). Conclusions The level of VEGF in aqueous humor was significantly higher in the failure group after the Ahmed glaucoma implantation compared with the success group. Our results imply that VEGF may play a role in determining surgical success after Ahmed Valve implantation in patients with NVG.

Faisal Almobarak - One of the best experts on this subject based on the ideXlab platform.

  • two year survival of Ahmed Valve implantation in the first 2 years of life with and without intraoperative mitomycin c
    Ophthalmology, 2009
    Co-Authors: Faisal Almobarak, Arif O. Khan
    Abstract:

    Purpose To evaluate the effect of intraoperative mitomycin-C (MMC) on polypropylene Ahmed glaucoma Valve (AGV) survival 2 years after implantation during the first 2 years of life. Design Retrospective institutional comparative series (1995–2005). Participants Thirty-one eyes of 27 patients (23 unilateral, 4 bilateral; 16 boys, 11 girls) undergoing AGV implantation at a mean age of 11.1 months (standard deviation [SD], 5.46), all of which had 2 years of regular postoperative follow-up. MMC was applied intraoperatively in those cases in the area of AGV implantation in 16 (52%) and was not applied in 15 (48%). In some eyes, MMC was applied intraoperatively in cases done by the surgeons who routinely used MMC for all AGV implantation in young children. Methods Failure was defined as intraocular pressure (IOP) > 22 mmHg with or without glaucoma medications, the need for an additional procedure for IOP control, or the occurrence of significant complications (e.g., endophthalmitis, retinal detachment, persistent hypotony [IOP Main Outcome Measures Failure or significant complications as defined. Results Mean survival for the non-MMC eyes (22.15 months; standard error [SE], 1.93) was significantly longer than survival for the MMC eyes (16.25 months; SE, 2.17) by the log-rank test ( P = 0.025). The difference in cumulative survival at 2 years was also significantly different by log-rank test ( P = 0.001): 80.0% (SE 10.3) and 31.3% (SE 11.6), respectively. Conclusions Rather than improved survival, intraoperative use of MMC was associated with shorter survival 2 years after AGV implantation during the first 2 years of life. We speculate that MMC-induced tissue death can stimulate a reactive fibrosis around the AGV in very young eyes. Financial Disclosure(s) The authors have no proprietary or commercial interest in any of the materials discussed in this article.

  • complications and 2 year Valve survival following Ahmed Valve implantation during the first 2 years of life
    British Journal of Ophthalmology, 2009
    Co-Authors: Faisal Almobarak, Arif O. Khan
    Abstract:

    Aim: To report complications and 2-year Valve survival following Ahmed Valve implantation during the first 2 years of life. Methods: Retrospective institutional case series. Results: Forty-two eyes of 36 patients with Ahmed Valve implantation (without prior drainage device surgery) during the first 2 years of life and 2 years’ postsurgical follow-up were identified. Most eyes had primary congenital glaucoma (28/42, 66.7%), aphakic glaucoma (5/42, 11.9%) or Peters anomaly (5/42, 11.9%). All but three eyes had prior ocular surgery. Surgery was at a mean age of 11.83 months (m) (SD 5.63). The most common significant postoperative complications were tube malpositioning requiring intervention (11/42, 26.2%), endophthalmitis (3/42, 7.1%; one with tube exposure) and retinal detachment (3/42, 7.1%). Thirty-six eyes (85.8%) required resumption of antiglaucoma medications to maintain intraocular pressure (IOP) ⩽22 mm Hg a mean of 7.2 m (SD 6.8) postoperatively. Cumulative probabilities of Valve survival (IOP⩽22 mm Hg with or without medication) by Kaplan–Meier analysis were 73.8% and 63.3% at 12 months and 24 months, respectively. Conclusions: Postoperative tube malpositioning that required surgical revision was common in this age group. Infectious endophthalmitis and retinal detachment are known potential complications following any incisional surgery for advanced buphthalmos; however, tube exposure is a unique potential problem following aqueous shunt implantation that can lead to intraocular infection. Cumulative Valve survival 2 years following implantation was 63.3%.

Stephen C Foster - One of the best experts on this subject based on the ideXlab platform.

  • long term results of Ahmed glaucoma Valve implantation for uveitic glaucoma
    American Journal of Ophthalmology, 2007
    Co-Authors: Thekla Papadaki, Peter A Netland, Ioannis Zacharopoulos, Louis R Pasquale, William B Christen, Stephen C Foster
    Abstract:

    Purpose To present long-term outcomes of Ahmed glaucoma Valve implantation for uveitic glaucoma. Design Interventional case series. Methods Retrospective chart review of 60 patients (60 eyes) with uveitic glaucoma who underwent Ahmed Valve implantation over a four-year period at a tertiary uveitis referral center. Success definition 1 included patients with an intraocular pressure (IOP) between 5 and 21 mm Hg, reduced by 25% from that before implantation. Success definition 2 (qualified success) excluded those patients in whom serious complications occurred. Results Mean follow-up time was 30 months (range, six to 87 months; four-year results relate to a cohort of 15 patients). Success rates were 77% and 50% and qualified success rates were 57% and 39% at one and four years, respectively. At four years, 74% of the patients required glaucoma medication to maintain IOP control. The overall complication rate was 12%/person-years. The rate of visual acuity loss was 4%/person-years; that was most commonly attributed to corneal complications that were more likely to occur in patients with preoperative corneal disease (P = .01, Fisher exact test). Conclusions Ahmed glaucoma Valve implantation is a safe yet moderately successful procedure for uveitic glaucoma. Long-term success rates are enhanced with the use of glaucoma medications, and corneal complications are the most common of all potential serious complications.

  • ocular cicatricial pemphigoid keratomycosis and intravenous immunoglobulin therapy
    Cornea, 2004
    Co-Authors: Barbara Iaccheri, Thekla Papadaki, Manolette Roque, Tito Fiore, Benjamin Mathew, Stefanos Baltatzis, Barry Emara, A C Tokarewicz, Stephen C Foster
    Abstract:

    PURPOSE To report the case of a patient developing fungal keratitis in the context of uncontrolled ocular cicatricial pemphigoid (OCP), which, despite intravenous immunoglobulin (IVIg) and other immunomodulatory therapy, progressed to end-stage pemphigoid, with corneal opacification, ankyloblepharon, and xerosis. Keratoprosthesis (KPro) restored functional vision for the patient. METHODS A 39-year-old man presented with uncontrolled CP and corneal ulcer in the left eye. Conjunctival biopsy diagnosed OCP; corneal scraping and biopsy diagnosed the cause of the corneal ulcer. OCP was treated with systemic steroids, immunosuppressive drugs, and IVIg. Visual rehabilitation was accomplished with Ahmed Valve and a type II Dohlman KPro. RESULTS Immunohistology of the biopsied conjunctiva showed IgG at the epithelial basement membrane zone, confirming the clinical diagnosis of OCP. Microbiologic studies of the corneal biopsy specimen were negative for Acanthamoeba and herpes but positive for Aspergillus niger. The patient's keratomycosis resolved with topical antifungal therapy. Treatment with Dapsone, intravenous-pulse steroid, oral cyclophosphamide, and intravenous immunoglobulin (IVIg) failed to control the OCP, with resultant complete conjunctivization of the cornea. Keratoprosthesis improved the patient's visual acuity from hand movements to 20/20. CONCLUSIONS Patients with uncontrolled OCP are at increased risk of corneal infection. The difficulty in diagnosing keratomycosis and the relatively rare occurrence of OCP explain the uniqueness of our reported case. OCP may progress to "end-stage" disease despite therapy. Keratoprosthesis can restore vision in selected otherwise seemingly hopeless cases.