Twenty-Four-Month Outcome of Gonioscopy-Assisted Transluminal Trabeculotomy (GATT) in Eyes With Prior Corneal Transplant Surgery.

PURPOSE: Glaucoma is a well-known sequelae of corneal transplant surgery and is a leading cause of visual loss in this patient group. We evaluated the performance and safety of gonioscopy-assisted transluminal trabeculotomy (GATT) in this population. DESIGN: Noncomparative retrospective case series. PARTICIPANTS: Consecutive eyes of patients receiving the GATT procedure for uncontrolled intraocular pressure (IOP) following corneal transplant surgery from 2016 to 2019. METHODS: Retrospective analysis of eyes with a history of prior corneal transplant undergoing GATT at Glaucoma Associates of Texas between 2016 and 2019 was performed. Data included IOP, patient demographics, preoperative and postoperative medications, preoperative and postoperative corneal procedures, complications, and need for reoperation for IOP control. MAIN OUTCOME MEASURES: IOP reduction and medication use following the procedure. RESULTS: Thirty-nine eyes of 32 patients with prior corneal transplant surgery underwent a GATT procedure. Prior corneal surgery included penetrating keratoplasty (59.0%), Descemet's stripping endothelial keratoplasty (35.9%), Descemet's membrane endothelial keratoplasty (2.6%), and deep anterior lamellar keratoplasty (2.6%). Patient age ranged from 24 to 94 years (mean 68.0 y) with 44% female and 81% Caucasian. The majority of patients had secondary open angle glaucoma (64.1%). There was a significant reduction in IOP and number of medications at all postoperative time points after censoring patients requiring reoperation to control IOP (P<0.001). At 24 months the pressure decreased from baseline of 30.9±11.5 to 13.9±4.7 mm Hg. Medications decreased from 4.2±1.0 medications at baseline to 0.6±1.0 at 24 months. Visual acuities decreased significantly over the first postsurgical month (all P<0.05), but these recovered at subsequent follow-up visits with 2-Snellen line improvements exceeding losses from month 3 to 36. Seven eyes required reoperation for uncontrolled glaucoma at a median of 8.5 months (range: 1.6 to 16.2 mo) after GATT. The cumulative proportion of eyes undergoing repeat cornea surgery was 2.6%, 2.6%, and 14.3% at 12, 24, and 36 months post-GATT, respectively. CONCLUSIONS: This case series describes a group of glaucoma patients, with a history of prior corneal surgery, that were safely and successfully treated with GATT. While classically traditional glaucoma surgeries are considered the standard of care for eyes following corneal transplant surgery, GATT should be considered as a reasonable, safe and effective alternative for surgically lowering IOP.

Outcomes of bleb revision with ologen following filtering glaucoma surgery.

PURPOSE: This study reports long-term outcomes of bleb revision with ologen™ Collagen Matrix (Aeon Astron Europe BV, the Netherlands) for the surgical management of various bleb-related issues including persistent bleb leaks with or without associated hypotony, bleb dysesthesia, overhanging blebs, or hypotony after filtering glaucoma surgery. MATERIALS AND METHODS: A retrospective chart review was performed for patients who underwent ologen bleb revision from 2012 to 2019 at Glaucoma Associates of Texas. RESULTS: The study included 23 eyes of 22 patients undergoing bleb revision with the ologen implant. Mean age was 74.0 ± 11.3 years, 16 (69.6%) were female, and 13 (56.5%) were White. Indications for bleb revision included bleb leak (78.3%), dysesthesia (13.0%), and hypotony from an overfiltering bleb (8.7%). Mean preoperative intraocular pressure was 6.8 ± 4.1 mmHg and the number of medications was 0.3 ± 0.9. Median follow-up was 24 months (range: 12-84 months); all patients had at least 12 months of follow-up. At 1 year, mean intraocular pressure was 10.9 ± 4.6 mmHg on 0.2 ± 0.5 medications, and at last follow-up, mean intraocular pressure was 10.4 ± 3.6 mmHg on 0.3 ± 0.7 medications. Bleb morphology remained low, diffuse, and posterior. One patient developed kissing choroidal effusions requiring surgical drainage with subsequent stabilization of intraocular pressure and bleb function, and three patients required additional surgery due to persistent leaks or bleb failure; there were no other vision-threatening complications. CONCLUSIONS: Use of the ologen implant during surgical bleb revision is a useful surgical technique that confers long-term improvements in bleb morphology and stability of function.

Rescue of Failed XEN-45 Gel Implant by Nd:YAG Shock Wave to Anterior Chamber Tip to Dislodge Hidden Intraluminal Occlusion.

PURPOSE: The purpose of this study was to inform ophthalmic surgeons in a timely manner of the hidden problem of clear intraluminal cellular debris as a cause for XEN-45 failure and to describe low energy neodymium-doped yttrium aluminum garnet (Nd:YAG) laser revision with periluminal anterior chamber tip shockwave treatment to improve flow to the bleb. PATIENTS AND METHODS: Six patients with visibly patent stent lumen post XEN-45 surgery. These eyes developed rising intraocular pressure (IOP) with a history of excellent prior bleb formation and were treated successfully with Nd:YAG laser shockwave therapy to disperse assumed intraluminal cellular debris. The laser was aimed just anterior and axial to the intracameral tip of the gel stent through a gonioscopy lens. RESULTS: Six patients with an average age of 75 years (60 to 90 y), preoperative IOP of 30 mm Hg (16 to 52 mm Hg) on an average of 2 antiglaucoma medications (0 to 4) underwent periluminal anterior chamber tip shock wave at an average of 12 months (1 to 38 mo) from XEN-45 surgery. The IOP was immediately reduced to an average of 15 mm Hg (8 to 23 mm Hg) and last IOP averaged 15 mm Hg (10 to 23 mm Hg) on 1.5 medications (0 to 4) at 4 months post periluminal anterior chamber tip shock wave. CONCLUSION: Nd:YAG laser revision of hidden blockage of a XEN-45 gel implant with periluminal anterior chamber tip shockwave treatment can disperse invisible intraluminal cellular debris and improve flow in a failing XEN-45 microstent, especially when distal fibrosis is not excessive.

Vesicular Release of GABA by Mammalian Horizontal Cells Mediates Inhibitory Output to Photoreceptors.

Feedback inhibition by horizontal cells regulates rod and cone photoreceptor calcium channels that control their release of the neurotransmitter glutamate. This inhibition contributes to synaptic gain control and the formation of the center-surround antagonistic receptive fields passed on to all downstream neurons, which is important for contrast sensitivity and color opponency in vision. In contrast to the plasmalemmal GABA transporter found in non-mammalian horizontal cells, there is evidence that the mechanism by which mammalian horizontal cells inhibit photoreceptors involves the vesicular release of the inhibitory neurotransmitter GABA. Historically, inconsistent findings of GABA and its biosynthetic enzyme, L-glutamate decarboxylase (GAD) in horizontal cells, and the apparent lack of surround response block by GABAergic agents diminished support for GABA's role in feedback inhibition. However, the immunolocalization of the vesicular GABA transporter (VGAT) in the dendritic and axonal endings of horizontal cells that innervate photoreceptor terminals suggested GABA was released via vesicular exocytosis. To test the idea that GABA is released from vesicles, we localized GABA and GAD, multiple SNARE complex proteins, synaptic vesicle proteins, and Cav channels that mediate exocytosis to horizontal cell dendritic tips and axonal terminals. To address the perceived relative paucity of synaptic vesicles in horizontal cell endings, we used conical electron tomography on mouse and guinea pig retinas that revealed small, clear-core vesicles, along with a few clathrin-coated vesicles and endosomes in horizontal cell processes within photoreceptor terminals. Some small-diameter vesicles were adjacent to the plasma membrane and plasma membrane specializations. To assess vesicular release, a functional assay involving incubation of retinal slices in luminal VGAT-C antibodies demonstrated vesicles fused with the membrane in a depolarization- and calcium-dependent manner, and these labeled vesicles can fuse multiple times. Finally, targeted elimination of VGAT in horizontal cells resulted in a loss of tonic, autaptic GABA currents, and of inhibitory feedback modulation of the cone photoreceptor Cai, consistent with the elimination of GABA release from horizontal cell endings. These results in mammalian retina identify the central role of vesicular release of GABA from horizontal cells in the feedback inhibition of photoreceptors.

Visual Field Outcomes in the Tube Versus Trabeculectomy Study.

PURPOSE: To describe visual field (VF) outcomes in the Tube Versus Trabeculectomy (TVT) Study. DESIGN: Cohort analysis of patients in a multicenter randomized clinical trial. PARTICIPANTS: A total of 122 eyes of 122 patients, with 61 eyes in both the tube shunt and trabeculectomy groups. METHODS: The TVT Study is a multicenter randomized clinical trial comparing the safety and efficacy of tube shunt surgery (350-mm2 Baerveldt implant) and trabeculectomy with mitomycin C (MMC) (0.4 mg/ml for 4 minutes) in patients with previous cataract or glaucoma surgery. Enrolled patients underwent perimetry at baseline and annual follow-up visits. The VFs were included if the false-positive rate was ≤20% and false-negative rate was ≤35%. The VFs were excluded if visual acuity <20/400 or loss of ≥2 Snellen lines from baseline was attributed to an etiology other than glaucoma. Longitudinal linear mixed-effects models with best linear unbiased predictions (BLUPs) were applied to estimate rates of change in mean deviation (MD) for each treatment group. MAIN OUTCOME MEASURE: Rate of MD change during follow-up period. RESULTS: A total of 436 reliable VFs were analyzed, with an average of 3.6 VFs per eye. Baseline MD was -13.07 ± 8.4 decibels (dB) in the tube shunt group and -13.18 ± 8.2 dB in the trabeculectomy group (P = 0.99). The rate of change in MD was -0.60 dB/year in the tube group and -0.38 dB/year in the trabeculectomy group (P = 0.34). The 95% confidence intervals for the rates of MD change were -0.77 to -0.44 dB/year in the tube group and -0.56 to -0.20 dB/year in the trabeculectomy group. No significant difference in MD slope was seen when patients were categorized by percentage of visits with intraocular pressure (IOP) <18 mmHg or by average IOP. Univariable and multivariable risk factor analyses identified history of diabetes, elevated IOP, and worse MD as baseline factors associated with more rapid VF loss. CONCLUSIONS: Slow rates of VF loss were observed after randomized surgical treatment in the TVT Study, but no significant difference in the rate of VF loss was seen after tube shunt implantation and trabeculectomy with MMC. Patients with diabetes, higher IOP, and more severe VF loss at baseline were at higher risk for VF progression.

Historical Considerations and Innovations in the Perioperative Use of Mitomycin C for Glaucoma Filtration Surgery and Bleb Revisions.

Although there is a currently a revolution in angle-based procedures, subconjunctival filtration surgery with mitomycin C (MMC) wound modification remains a vital skill for glaucoma surgeons. MMC is a potent antifibrotic agent that has been an invaluable adjunct for successful glaucoma filtration surgery for over 20 years, but it must be used judiciously to avoid serious complications, including hypotony, corneal decompensation, bleb avascularity, bleb leaks, blebitis, and endophthalmitis. The purpose of this report is to describe the historical lessons learned from MMC use, along with updated methods of MMC delivery during primary trabeculectomy, bleb needling at the slit lamp, bleb revisions in the operating room, and newer and less invasive ab-interno filtering procedures. Information for the review was gathered using an extensive search on PubMed, a review of all available peer-reviewed literature, and the authors' personal clinical judgment and experience.

Early Results of Goniotomy with the Kahook Dual Blade, a Novel Device for the Treatment of Glaucoma.

PURPOSE: To report the outcomes of patients who underwent goniotomy with the Kahook Dual Blade (KDB) either as a standalone procedure or in combination with cataract extraction. PATIENTS AND METHODS: This retrospective chart review included 111 eyes of 90 patients who underwent KDB goniotomy from January to November 2016 at Glaucoma Associates of Texas. KDB goniotomy was combined with cataract surgery in 100 eyes. The main outcome measures were postoperative intraocular pressure (IOP) and number of IOP lowering medications. RESULTS: Preoperatively, mean IOP was 17.1 ± 4.7 mmHg (range 8-34 mmHg) and mean number of IOP lowering medications was 2.4 ± 1.3 (range 0-6). Postoperatively, mean IOP was 14.9 mmHg, 13.9 mmHg, 14.1 mmHg, 14.4 mmHg, and 14.7 mmHg at 1, 3, 6, 9, and 12 months follow-up, respectively (all p <0.004). Mean numbers of IOP lowering medications were 0.8, 1.0, 1.0, 1.0, and 1.6 at 1, 3, 6, 9, and 12 months follow-up, respectively (all p <0.001). The cumulative reoperation rates for uncontrolled IOP after KDB were 0%, 1.0%, 2.1%, and 4.6% at 3, 6, 9, and 12 months, respectively. Eyes with a preoperative IOP >21 mmHg were significantly more likely to undergo reoperation (p = 0.038, log-rank test). There were no serious complications at any time point in the follow-up period. CONCLUSION: The Kahook Dual Blade results in a reduction in IOP and use of glaucoma medications after one year of follow-up. Further prospective studies are needed to fully characterize safety and efficacy.

Micropulse Cyclophotocoagulation: Initial Results in Refractory Glaucoma.

PURPOSE: The purpose of this study is to evaluate the use of micropulse transscleral cyclophotocoagulation (MP-TSCPC), a new and increasingly popular treatment, in patients with uncontrolled glaucoma. METHODS: A retrospective chart review was performed for all patients who underwent a MP-TSCPC at the Glaucoma Associates of Texas. RESULTS: A total of 84 eyes were treated with MP-TSCPC in this study with a mean follow-up time of 4.3 months. The mean age of treated patients was 74 years and 48 (57%) were female. Preoperatively, mean intraocular pressure (IOP) was 27.7 mm Hg and mean number of ocular antihypertensive medications used was 3.3. Mean postoperative IOP at months 1, 3, 6, and 12 were lowered to 16.3 mm Hg (41.2% reduction), 14.6, 13.0, and 11.1 mm Hg, respectively. Postoperative ocular antihypertensive medication use was also lowered to 1.9, 2.0, 2.0, and 2.3 medications at months 1, 3, 6, and 12, respectively. Five patients required further laser or surgical intervention for adequate IOP control. Complications included hypotony, IOP spike, hyphema, serous choroidal detachment, persistent inflammation, and vision loss. At 3 months, inflammation was still present in 46% of eyes and vision loss of at least 1 line was present in 41% of eyes. CONCLUSIONS: MP-TSCPC is effective at lowering IOP and decreasing the need for ocular antihypertensive medications. Eyes with limited visual potential or at high risk for incisional glaucoma surgery can successfully be treated with MP-TSCPC as a reasonable and effective alternative to traditional CPC. These results present short-term data and both longer follow-up and further studies are necessary.

Glaucoma management after corneal transplantation surgeries.

PURPOSE OF REVIEW: Intraocular pressure (IOP) elevation and glaucoma progression following corneal transplantation, specifically, penetrating keratoplasty, Descemet's stripping endothelial keratoplasty, and Boston keratoprosthesis, are well described causes of ocular morbidity. Depending on the procedure performed, the incidence of glaucoma is highly variable. Several etiologic factors have been identified, the most common being synechial angle closure and corticosteroid-induced IOP elevation. The purpose of this review is to describe the various treatment strategies for glaucoma following corneal transplantation. RECENT FINDINGS: Medications and laser treatments are usually first-line therapies for postoperative IOP elevation. Surgical intervention, including filtering surgery and glaucoma drainage devices, may be necessary to control IOP and prevent progressive glaucomatous damage. SUMMARY: Glaucoma is a common complication of corneal transplantation, and the degree of aggressiveness is often related to the indication for corneal surgery. Although postoperative IOP elevation may be controlled with medical therapy alone, refractory cases may require glaucoma surgery. In all cases, early detection and intervention are necessary to optimize patient outcomes.

Glaucoma management after vitreoretinal surgeries.

PURPOSE OF REVIEW: The surgical management of retinal disorders, including scleral buckling procedures, pars plana vitrectomy, and intravitreal injections of gas or silicone oil, can lead to short-term elevations in intraocular pressure (IOP) and ultimately long-term glaucomatous damage if not treated in a timely manner. Glaucoma in these cases is commonly refractory to conventional therapies. This review highlights the treatment strategies for glaucoma in eyes that have previously undergone vitreoretinal surgery. RECENT FINDINGS: Although medical therapy is often used initially to control a temporary rise in IOP, laser and surgical therapy may be required to treat sustained IOP elevation and subsequent glaucomatous damage in eyes that have undergone intraocular surgery for retinal disorders. Glaucoma drainage devices are an important treatment modality, particularly when there is high risk of failure with filtering surgery. SUMMARY: Previous vitreoretinal surgery is a known risk factor for the development of glaucoma. Treatment is usually initiated with medical therapy, however, surgical intervention is frequently required to control IOP and prevent progressive glaucomatous damage in patients with refractory glaucoma.

Early Aqueous Suppressant Therapy on Hypertensive Phase Following Glaucoma Drainage Device Procedure: A Randomized Prospective Trial.

PURPOSE: To prospectively evaluate the effect of early aqueous suppression (therapy) on hypertensive phase (HP) and intraocular pressure (IOP) control after implantation of silicone Ahmed glaucoma valve (AGV). MATERIALS AND METHODS: Patients who underwent AGV implantation were randomized to initiate therapy (including ß-blockers, α-agonists, or carbonic anhydrase inhibitors) when postoperative IOP>10 mm Hg (low-IOP initiation group) or >17 mm Hg (moderate-IOP initiation group). HP was defined as an IOP>21 mm Hg during the first 6 postoperative months, after an initial IOP reduction to <22 mm Hg in the first postoperative week. Primary outcome measures included the occurrence of HP and IOP control. RESULTS: Fifty-two eyes (50 patients) underwent AGV implantation. Average follow-up was 21.9±10.7 months. HP was observed in 21 eyes (40.4%) with average peak IOP of 30±8 mm Hg, onset at 32±30 days, and duration of 15±32 days. One year postoperatively, those eyes with HP had higher IOP than eyes that did not develop HP (15.1±5.2, 11.4±4.3, respectively; P=0.021) and required more additional glaucoma surgeries (28.6%, 3.2%, respectively; P=0.013). The peak IOP at week 3 postoperatively in the low-IOP initiation group (26 eyes) was significantly lower than in the moderate-IOP initiation group (26 eyes; 15.7±3.6, 20.6±8.9, respectively; P=0.012). Eyes with therapy started after HP onset had significantly higher postoperative IOP from 2 to 4 months. Therapy initiated before the development of HP was not associated with a higher complication rate. CONCLUSIONS: Aqueous suppression initiated in the early postoperative period while IOPs were still in the low-teens and was able to reduce the incidence of IOP spike associated with the HP without an increased complication rate.

Evaluation of the "IS" Rule to Differentiate Glaucomatous Eyes From Normal.

PURPOSE: To compare the accuracy of the "ISNT" rule [neural rim width of inferior(I)≥superior(S)≥nasal(N)≥temporal(T) regions] and the abbreviated variant, the "IS" rule (inferior≥superior regions) to differentiate normal from glaucomatous eyes. MATERIALS AND METHODS: Medical records of patients who were evaluated in 2011, had glaucomatous optic neuropathy and visual field defects, on glaucoma treatment, and had stereoscopic optic disc photographs were reviewed. Optic discs with focal complete loss of neural rim or long axis rotated >30 degrees from vertical meridian, and patients with ≥5 D of myopia or any retinal pathology or nonglaucomatous optic neuropathy were excluded. One eye per patient was randomly enrolled. Normal control eyes were also included. Rim widths were measured with an image processing program (ImageJ, National Institutes of Health) in a masked manner. The sensitivity and specificity of the ISNT rule, the IS rule, and cup-to-disc ratio (CDR) were compared. RESULTS: A total of 134 glaucoma and 110 normal eyes were enrolled. The mean CDRs of the glaucoma and normal eyes were 0.65±0.13 and 0.39±0.15, respectively. Sensitivities of the ISNT and IS rules were 85% and 41%, respectively, whereas specificities were 46% and 85%, respectively. Application of the IS rule in eyes with larger CDR (>0.57) increased the specificity of the IS rule to 93% while keeping the sensitivity at 41%. When ISNT or IS rule and CDR>0.57 were combined in differentiating normal from glaucomatous eyes for the entire sample, specificities approached 90% and 99%, respectively. CONCLUSIONS: The ISNT rule alone has a high sensitivity but relatively low specificity. Application of the IS rule in eyes with increased CDR yields a much higher specificity for differentiating normal from more advanced glaucomatous eyes. A combination of different features of the optic disc (increase of CDR and ISNT or IS rule) improves the specificity of optic disc evaluation for glaucoma.