Re-descemet membrane endothelial keratoplasty (DMEK) with preservation of the original graft after free roll in anterior chamber: A case report.

INTRODUCTION: Lamellar keratoplasties have had a great impact in the management of corneal edema due to endothelial dysfunction. Minimally invasive transplant techniques such as Descemet Membrane Endothelial Keratoplasty (DMEK) have helped to reduce the morbidity involved in performing penetrating keratoplasty in this type of patient. Even so, these are complex techniques that are not free of complications and require a long line of surgical learning and an even more demanding experience in postoperative management. CLINICAL CASE: An 89-year-old woman suffering from Fuchs endothelial dystrophy and undergoing combined cataract and DMEK surgery presented stromal edema predominantly inferior and sectoral detachment of the graft 24 h after the intervention. After re-bubbling in consultations and 4 days later, the graft was observed rolled and free in the anterior chamber. She underwent re-DMEK with preservation of the original graft after 24 h, with de-epithelialization to optimize visualization. The graft was stained with trypan blue and the posterior stroma was protected with air. The graft was reimplanted under intraocular maneuvers and with an air bubble. 24 h after surgery, the adhered graft was observed, with a great decrease in stromal edema. One month later, the patient had a clear cornea, persistent complete graft adhesion, and visual acuity of 0.9. CONCLUSION: The discovery of free roll in the anterior chamber after DMEK surgery constitutes the most complex form of graft detachment. Corneal edema as well as the arrangement of the different intraocular structures are conditions to be considered for the surgical resolution of this complication. In many cases, surgical repositioning of the graft is feasible, which means saving costs without the need to use new donor corneal tissues.

Chamber shallowing technique for challenging DMEK cases: Tucking cellulose spears under the speculum to augment posterior pressure.

Some anterior chambers do not readily shallow because of insufficient posterior pressure and/or very deep anterior chamber anatomy, which can make unscrolling descemet membrane endothelial keratoplasty (DMEK) tissue more challenging with an unmodified tap technique. We present a hands-free method for augmenting posterior pressure by temporarily tucking cellulose sponges under the blades of the eyelid speculum. The sponges transfer some of the eyelid speculum's weight onto the bulbar surface posterior to the iris, thereby indenting the sclera and causing the iris diaphragm to bulge further forward. This hands-free technique can transform a potentially challenging DMEK case into a more straightforward one by facilitating both a shallow anterior chamber and a bimanual unscrolling technique. However, it only works in bicameral eyes with a vitreous body (e.g., an eye with penetrating keratoplasty, vitreous syneresis, and axial myopia) and will not work in unicameral eyes after vitrectomy (e.g., an eye with an Anterior Chamber Intraocular Lens (ACIOL)).

In vivo evaluation of a nanotechnology-based microshunt for filtering glaucoma surgery.

To carry out the preclinical and histological evaluation of a novel nanotechnology-based microshunt for drainage glaucoma surgery. Twelve New Zealand White rabbits were implanted with a novel microshunt and followed up for 6 weeks. The new material composite consists of the silicone polydimethylsiloxane (PDMS) and tetrapodal Zinc Oxide (ZnO-T) nano-/microparticles. The microshunts were inserted ab externo to connect the subconjunctival space with the anterior chamber. Animals were euthanized after 2 and 6 weeks for histological evaluation. Ocular health and implant position were assessed at postoperative days 1, 3, 7 and twice a week thereafter by slit lamp biomicroscopy. Intraocular pressure (IOP) was measured using rebound tonometry. A good tolerability was observed in both short- and medium-term follow-up. Intraocular pressure was reduced following surgery but increased to preoperative levels after 2 weeks. No clinical or histological signs of inflammatory or toxic reactions were seen; the fibrotic encapsulation was barely noticeable after two weeks and very mild after six weeks. The new material composite PDMS/ZnO-T is well tolerated and the associated foreign body fibrotic reaction quite mild. The new microshunt reduces the IOP for 2 weeks. Further research will elucidate a tube-like shape to improve and prolong outflow performance and longer follow-up to exclude medium-term adverse effects.

Direct observation and measurement of circumlental space and its relation to anterior chamber angle characteristics in iridotomized phakic eyes with primary angle closure disease.

Primary angle closure disease (PACD) is a major cause of blindness worldwide. It has a high prevalence in East Asia, especially in China, which leads to a higher incidence of blindness than open-angle glaucoma. The aim of this study was to directly observe the circumlental space (CLS) in laser peripheral iridotomized eyes with PACD and to determine whether this structure plays a role in the pathogenesis of PACD. Fifty eyes of 50 patients with PACD, who had received laser peripheral iridotomy performed with neodymium:yttrium-aluminum-garnet were recruited from glaucoma clinics from March 2021 to May 2022, including 17 primary angle closure suspect (PACS), 16 primary angle closure (PAC) and 17 primary angle closure glaucoma (PACG). They were classified into two groups based on whether the ciliary process and the crystalline lens equator were in contact using slit-lamp photograph: the attached group and the unattached group. The demographic, clinical characteristics and anterior segment parameters measured from ultrasound biomicroscopy were compared between the attached group and the unattached group. Thirty-three eyes were assigned to the attached group and 17 eyes belonged to the unattached group. In the unattached group, the mean CLS was 0.10 ± 0.07 mm. No significant differences were identified between the different diagnosis groups in age, sex, best-corrected visual acuity, intraocular pressure, white-to-white, axial length, central corneal thickness, anterior chamber depth, flat keratometry, steep keratometry or iridotomy diameter (p > 0.05). The unattached group had shorter trabecular-ciliary process distance (p = 0.021) and larger ciliary process area (p = 0.001) compared with the attached group. Small CLS and its potential effect (partial ciliary block) might be considered as one of the mechanisms of PACD.

Real-time in vivo monitoring of intraocular pressure distribution in the anterior chamber and vitreous chamber for diagnosis of glaucoma.

Glaucoma causes irreversible vision loss due to optic nerve damage and retinal cell degeneration. Since high intraocular pressure (IOP) is a major risk factor for glaucoma development, accurate IOP measurement is crucial, especially intravitreal IOP affecting the optical nerve and cells. However, conventional methods have limits in selectively and directly detecting local retina pressure. Here, we present continuous measurements of local IOP values in the anterior chamber and vitreous chamber of living animals using minimally invasive probes with pressure-sensitive transistors. After inducing glaucoma in animal models, we compared the local IOP distribution between normal and glaucomatous eyes. We also compared IOP values detected in the cornea using tonometry measurements. Our findings revealed that glaucoma induced higher IOP in the vitreous chamber than in the anterior chamber, indicating that measuring IOP in the vitreous chamber is key to the glaucoma model. This progress offers future directions for diagnosis and treatment of glaucoma.

Comparison of cosmesis, mydriasis, fundus visibility, and anterior chamber depth following single-pass four-throw pupilloplasty in congenital and traumatic iris defects.

PURPOSE: To compare postoperative cosmesis, mydriasis, fundus visibility, and anterior chamber depth (ACD) in congenital and traumatic iris defects after single-pass four-throw pupilloplasty (SFTP). SETTINGS AND DESIGN: Hospital-based non-randomized interventional study. METHODS: SFTP was done along with phacoemulsification in six patients each with congenital and traumatic iris defects, and the patients were followed for a minimum period of 3 months. The postoperative pupil shape, size, mydriasis, and ACD were compared between the two groups. RESULTS: Tissue approximation was successful in 11 out of 12 patients (91.7%), whereas it failed to do so in one patient with traumatic iris tear (8.3%). A central round pupil was attained in all six patients with congenital defects (group 1), whereas in the traumatic group (group 2), a central round pupil was attained in four cases. Group 1 did not show a significant reduction in horizontal pupil diameter, but group 2 had a significant reduction in pupil diameter postoperatively. Mydriasis and fundus visibility were satisfactory in all cases. There was a significant deepening of ACD in both groups. CONCLUSION: Traumatic mydriasis usually requires SFTP at two opposite poles to achieve a central pupil with a significant reduction in pupil size, whereas congenital coloboma requires SFTP to be done at the site of coloboma with occasional enlargement at the opposite pole if the pupil is eccentric.

Reverse 4-Throw Pupilloplasty for Endothelial Keratoplasty.

PURPOSE: The aim of this study was to describe the feasibility and applicability of a reverse 4-throw (RFT) pupilloplasty technique for endothelial keratoplasty. METHODS: In RFT, the 9-0 polypropylene suture needle and a 26-Gauge needle pierce the iris tissue from the posterior surface to emerge on the anterior surface along the proximal and distal portion of iris tissue to be apposed, respectively. The 9-0 needle is threaded into the barrel of a 26-Gauge needle and is withdrawn from the eye. The suture loop is withdrawn and the suture end is passed through the loop 4 times. Both suture ends are pulled, which leads to the sliding of the loop inside the eye, thereby apposing the iris tissue with the knot lying on the posterior surface. RESULTS: The procedure was performed in 11 eyes of 11 patients who were scheduled to undergo an endothelial keratoplasty procedure. The anterior segment optical coherence tomography image of the RFT pupilloplasty did not denote any presence of the suture in the anterior chamber or along the anterior surface of the iris plane. No incidence of primary graft failure or graft rejection during the entire follow-up period was reported in any of the eyes. CONCLUSIONS: RFT serves as an effective technique for performing pupilloplasty in endothelial keratoplasty cases without the presence of a knot or suture tail in the anterior chamber.

Comparison of efficacy of three gases for anterior chamber tamponade in Descemet's membrane endothelial keratoplasty.

PURPOSE: To compare the efficacy of three different gases for intraocular tamponade: 100% air, 10% perfluoropropane (C3F8), and 10% sulfur hexafluoride (SF6), in Descemet's membrane endothelial keratoplasty (DMEK). MATERIALS AND METHODS: The medical records of 138 patients who underwent DMEK were reviewed retrospectively, with the primary outcome being the rebubbling rate in the first week following surgery. Other clinical outcomes, such as best-corrected visual acuity (BCVA), central corneal thickness (CCT), incidence of rebubbling after the first week, endothelial cell density (ECD), graft detachment, graft failure, pupillary block, and intraocular pressure (IOP) changes were also analyzed. RESULTS: Of the 138 patients, 57 were in group 1 (treated with air), 44 in group 2 (treated with 10% C3F8), and 37 in group 3 (treated with 10% SF6). Group 3 showed significantly lower rates of graft detachment and rebubbling compared to groups 1 and 2 (P<0.001). However, there was no significant difference in postoperative BCVA among the groups. At one year, the mean endothelial cell loss was 32% in group 1, 30% in group 2, and 33% in group 3 (P=0.715). One patient in group 1 experienced pupillary block and increased IOP, while there were no such occurrences in the other groups. There was no difference between the groups in terms of graft failure. CONCLUSION: The use of 10% SF6 in DMEK surgery may be a good option due to its efficacy in preventing graft detachment, low rebubbling rate, and potential for minimizing complications.

Management of an inadvertent late filtering bleb and hypotony in a scleral fixated intraocular lens implantation.

PURPOSE: To report a case of inadvertent cystic filtering bleb in a patient with scleral fixated intraocular lens (SFIOL) implantation 7 years after initial procedure. CASE PRESENTATION: A 14-year-old boy underwent lensectomy, vitrectomy and a sutured rigid SFIOL for microspherophakia in the right eye. Seven years later, the patient presented with hypotony related ocular changes. Examination revealed an inadvertent cystic filtering bleb at the scleral section. Anterior segment optical coherence tomography (ASOCT) revealed gap in inner lips of the scleral wound, bridged by a thin strip of scleral tissue. A conservative management with bandage contact lens (BCL) failed after an initial improvement. Injection of trypan blue dye in the anterior chamber confirmed the presence and site of wound filtration. Surgical closure of the fistula was done and patient showed both structural and visual improvement. CONCLUSION: Meticulous wound construction and water tight closure at the end of the surgery can avoid such complications. ASOCT can be helpful in diagnosing the area of fistula. A conservative management with BCL can help by tamponading the filtering bleb. However, in unresponsive cases, surgical closure of the fistula is recommended to improve the hypotony-related changes.

Investigation of Needle Characteristics Using an Animal Model for Improved Outcomes in Anterior Chamber Paracentesis.

Background/Aims: The current standard of care to perform an anterior chamber paracentesis involves the use of a multipurpose market needle and syringe. The use of standard needles for this purpose may result in injury to the patient due to increased force with insertion and increased globe displacement during the procedure. This research investigates the current market needle characteristics and the impact of each needle characteristic on force. Methods: Several comparative trials were conducted to evaluate the needles. Needle characteristics of interest were gauge, primary bevel angle, number of bevels in the lancet, and needle hub geometry. Measurements of corneal insertion forces were made using a synthetic thermoplastic polyurethane medium, and bovine and porcine models. Needle safety was investigated with corneal abrasion experiments. Results: Reduced insertion force was observed with lower lancet primary angle. There was no difference based on the number of bevels in the lancet. Rounded hub geometry had minimal distribution to the corneal epithelium. Conclusions: Needle characteristics impact the force needed for needle insertion into the tissue. Since higher force can lead to increased risk and less efficiency during the procedure, reducing this force may improve the outcomes of the procedure. Needle entry can be reduced by designing an improved needle that includes a lower gauge and reduced primary angle of the lancet.

Anterior Chamber Snowflake After Keratoplasty.

A 62-year-old woman presented with painless vision reduction and eye redness in the right eye for a week. Nine months after keratoplasty, she presented with diffuse tiny nodules all over the iris and a dense opacity in the anterior vitreous body. What would you do next?

Dislocated Descemet Stripping Endothelial Keratoplasty Lenticule in the Anterior Chamber.

This case report discusses the dislocation of a Descemet stripping endothelial keratoplasty (DSEK) lenticule in a man aged 82 years who underwent DSEK for pseudophakic bullous keratopathy.

Risk Factors for Flat Anterior Chamber Requiring Intervention After Glaucoma Drainage Implant: A Retrospective Case-Controlled Study.

PURPOSE: To identify risk factors for flat anterior chamber that required additional intervention in the postoperative period (90 days) after uncomplicated Baerveldt Glaucoma Implant (BGI) surgery. DESIGN: Retrospective, matched case-control study. METHODS: A total of 42 cases (eyes) that received BGI at Anne Bates Leach Eye Hospital between February 1, 2011, and January 1, 2019, and that developed flat anterior chamber were included. For each case, we matched 2 controls (84). Variables included sex, diagnosis, diabetes, hypertension, pre- and postoperative glaucoma medications, ocular conditions, and intraocular pressure (IOP). Multivariable conditional logistic regression determined odds ratios (ORs) for independent predictors. RESULTS: Case patients were more likely to be female (69.1% case patients/41.7% controls), to have a history of taking oral carbonic anhydrase inhibitors (CAIs) at tube opening (21.4%/7.1%), to be of another race/ethnicity (11.9%/0.0%), and to have pseudoexfoliation (23.8%/6.0%), and were less likely to be using cholinergic agonists (0.0%/11.9%) at baseline and to have primary open angle glaucoma (42.9%/64.3%). Case patients had greater mean age (75.9/64.9 years), earlier tube opening time (5.6/6.2 weeks), and lower IOP after tube opening (7.2/14.4 mm Hg), but IOP before opening was higher (24.7/19.5 mm Hg). We identified 3 independent predictors: older age (10-year increase OR = 3.59, P < .0001), oral CAI use at tube opening (OR = 5.65, P = .009), and higher IOP prior to tube opening (3 mm Hg increase OR = 1.30, P = .018). CONCLUSION: Risk factors for flat anterior chamber were older age, oral CAIs at tube opening, and higher IOP before tube opening. Strategies to minimize the acute IOP reduction that preceded this complication such as discontinuing oral CAI prior to tube opening may be considered.

Exploration on surgery of malignant glaucoma with prolonged absence of the anterior chamber: a retrospective consecutive case series.

OBJECTIVE: To evaluate the surgical outcomes of anterior chamber restoration in patients with malignant glaucoma and a prolonged absence of the anterior chamber. METHODS: Five patients with malignant glaucoma and a long-term absence of the anterior chamber underwent a combination of anterior pars plana vitrectomy (aPPV), phacoemulsification cataract excision, intraocular lens implantation, peripheral iridotomy (PI), goniosynechialysis (GSL) (referred to aPPV + P + I + PI + GSL) at Beijing Tongren Hospital from October 2018 to June 2021. The study compared the changes in their visual acuity, intraocular pressure (IOP) and medication requirements between the pre-surgery period and their most recent follow-up visit. RESULTS: The five patients did not report any discomfort, such as pain, tearing, swelling, etc., in their affected eyes, and maintained a stable restoration of the anterior chamber. Among the affected eyes, only one eye demonstrated improved vision during the follow-up visit, while the remaining four eyes did not show any significant improvement. One eye underwent transscleral cyclophotocoagulation as an additional procedure, while the other four eyes did not require any further surgical intervention. In all cases, the intraocular pressure (IOP) was successfully controlled below 30 mmHg. Post-surgery, four eyes still required cycloplegia treatment, and three eyes continued to rely on eye drops to manage their IOP. CONCLUSION: Despite minimal improvement in vision, surgical intervention successfully restored the anterior chamber in malignant glaucoma patients with a prolonged absence of anterior chamber. This restoration contributed to alleviating subjective complaints of discomfort and delaying eyeball atrophy.

Suture manipulation post-trabeculectomy: A practical guide.

Background: Trabeculectomy is the gold standard filtration surgery for diverting aqueous from anterior chamber to the subconjunctival space. More than the surgery, postoperative follow-ups and management of the blebs play a critical role in the long-term success. This video is aimed at showing the real-world management of blebs postoperatively. Purpose: This video will serve as a practical guide to the postoperative management of trabeculectomy blebs with specific focus on the suture manipulation. Synopsis: This video will demonstrate various suturing techniques of trabeculectomy and their manipulation in the postoperative period. Complications related to each will be discussed. Highlights: We demonstrate how to place and remove, releasable, and fixed sutures. We also address the practical points on why and when to remove the sutures. Suture-related complications and their management have been shown along with practical examples. Video Link: https://youtu.be/2WFQJAPyOvY.

Experimental study comparing 2 different phacoemulsification systems with intraocular pressure control during steady-state flow and occlusion break surge events.

PURPOSE: To compare peak surge and surge duration time after occlusion break, incision leakage compensation, and passive vacuum for 2 phacoemulsification systems. SETTING: Carl Zeiss Meditec AG, Oberkochen, Germany. DESIGN: Laboratory study. METHODS: A spring-eye model was used to test Alcon Centurion Vision and Zeiss Quatera 700 systems. Peak surge and duration was measured after an occlusion break. Quatera tested in flow and vacuum priority modes. Vacuum limits ranged from 300 to 700 mm Hg with intraocular pressure (IOP) set at 30 mm Hg, 55 mm Hg, and 80 mm Hg. IOP vs incision leakage rates of 0 to 15 cc/min and passive vacuum were measured. RESULTS: At 30 mm Hg IOP set point and vacuum limits ranging 300 to 700 mm Hg, the surge duration time after occlusion break ranged 419 to 1740 milliseconds (ms) for Centurion, 284 to 408 ms for Quatera in the flow mode, and 282 to 354 ms for Quatera in the vacuum mode. At 55 mm Hg, values ranged 268 to 1590 ms for Centurion, 258 to 471 ms for Quatera in the flow mode, and 239 to 284 ms for Quatera in the vacuum mode. At 80 mm Hg, values were 243 to 1520 ms for Centurion, 238 to 314 ms for Quatera in the flow mode, and 221 to 279 ms in the vacuum mode. Centurion exhibited slightly less peak surge than the Quatera. At 55 mm Hg: incision leakage rates 0 to 15 cc/min, Quatera held the IOP within ±2 mm Hg of target; Centurion was unable to hold IOP target allowing a 11.7 mm Hg decrease with 32% higher passive vacuum. CONCLUSIONS: Quatera demonstrated slightly higher surge peak values and notably shorter surge duration times after occlusion break than Centurion. Quatera demonstrated better incision leakage compensation and lower passive vacuum than Centurion.

Greater Outflow Facility Increase After Targeted Trabecular Bypass in Angiographically Determined Low-low Regions.

PURPOSE: To investigate the impact of trabecular bypass surgery targeted to angiographically determined high- vs. low-aqueous humor outflow areas on outflow facility (C) and intraocular pressure (IOP). DESIGN: Ex vivo comparative study. SUBJECTS: Postmortem ex vivo porcine and human eyes. METHODS: Porcine (n = 14) and human (n = 13) whole globes were acquired. In both species, anterior segments were dissected, mounted onto a perfusion chamber, and perfused using Dulbecco's phosphate buffered solution containing glucose in a constant flow paradigm to achieve a stable baseline. Fluorescein was perfused into the anterior chamber and used to identify baseline segmental high- and low-flow regions of the conventional outflow pathways. The anterior segments were divided into 2 groups, and a 5 mm needle goniotomy was performed in either a high- or low-flow area. Subsequently, C and IOP were quantitatively reassessed and compared between surgery in baseline "high-flow" and "low-flow" region eyes followed by indocyanine green angiography. MAIN OUTCOME MEASURES: Outflow facility. RESULTS: In all eyes, high- and low-flow segments could be identified. Performing a 5-mm goniotomy increased outflow facility to a variable extent depending on baseline flow status. In the porcine high-flow group, C increased from 0.31 ± 0.09 to 0.39 ± 0.09 µL/mmHg/min (P = 0.12). In the porcine low-flow group, C increased from 0.29 ± 0.03 to 0.56 ± 0.10 µL/mmHg/min (P < 0.001). In the human high-flow group, C increased from 0.38 ± 0.20 to 0.41 ± 0.20 µL/mmHg/min (P = 0.02). In the human low-flow group, C increased from 0.25 ± 0.11 to 0.32 ± 0.11 µL/mmHg/min (<0.001). There was statistically significant greater increase in C for eyes where surgery was targeted to baseline low-flow regions in both porcine (0.07 ± 0.09 vs. 0.27 ± 0.13, P = 0.007 µL/mmHg/min, high vs low flow) and human eyes (0.03 ± 0.03 vs. 0.07 ± 0.02, P = 0.03 µL/mmHg/min, high vs. low flow). CONCLUSIONS: Targeting surgery to low-flow areas of the trabecular meshwork yields higher overall facility increase and IOP reduction compared to surgery in high-flow areas. FINANCIAL DISCLOSURE(S): Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.