Microvitreoretinal Blade Research Articles

Prospective comparison of minimally invasive glaucoma surgery techniques for goniotomy in primary congenital glaucoma: Optimizing intraocular pressure control

BackgroundA family of less invasive glaucoma procedures has been developed to provide moderate reductions in intraocular pressure and medication burden in eyes with therapeutic needs that may not warrant the risks associated with trabeculectomy and tube shunt implantation. This study aims to compare the effectiveness and clinical outcomes of pediatric goniotomy using minimally invasive glaucoma surgery techniques to manage primary congenital glaucoma. Materials and methodsUsing a computer-generated set of random numbers, the patients were randomized into three groups: Kahook blade group, microvitreoretinal blade group, and 23G needle group. Each group contained 22 eyes. All patients underwent anesthesia for intraocular pressure measurement, corneal diameter evaluation, and fundoscopy. Preoperative intraocular pressure at presentation and postoperative intraocular pressure were recorded during a one-year follow-up period. Outcome measures included decreases in corneal diameter from preoperative size, mean postoperative reduction in intraocular pressure for each minimally invasive glaucoma surgery technique and absence of intraoperative or postoperative complications. Surgical success was defined as a postoperative intraocular pressure of ≤20 mmHg without antiglaucoma medications or reoperation, based on the last recorded intraocular pressure during postoperative follow-up. ResultsA total of 66 eyes were diagnosed with primary congenital glaucoma and underwent goniotomy surgeries during the study period in 2022. The majority (89%) were bilateral cases. Among the patients, there were 26 males and 9 females, which makes up an 8: 2 male-to-female ratio, with an average age range of 2 months to 2 years. After a one-year postoperative follow-up, a significant reduction in intraocular pressure was achieved of ≤18 mmHg. In terms of surgical success with minimally invasive glaucoma surgery techniques, goniotomy with a 23-gauge needle had the most postoperative intraocular pressure, followed by the microvitreoretinal blade and the Kahook blade. On average, the 23-gauge needle had a corneal diameter of 13.8 mm, while the microvitreoretinal blade was 13.9 mm and the Kahook blade recorded 14 mm. ConclusionsGoniotomy using minimally invasive glaucoma surgery techniques has been proven to be an effective surgical technique for the management of childhood glaucoma among Nigerian patients. A reduction in postoperative intraocular pressure, corneal diameter, and absence of complications provide clinical evidence of successful glaucoma management and preservation of outcomes of visual function in patients. Level of evidenceLevel 1 (Prospective study)

Kissing microvitreoretinal blade technique: A novel approach for safe and effective endocapsular lens aspiration in microspherophakia.

We herein describe the kissing MVR technique in cases of microspherophakia for safe and effective endocapsular lens aspiration. Microspherophakia is associated with abnormally lax and broken zonules, which pose a great challenge to the operating surgeon, especially while creating the openings in the capsular bag. In this novel technique, simultaneous use of two 23 G MVR blades reduces the above problem associated with the severely mobile lens. Here, one MVR blade stabilizes the capsular bag and, at the same time, provides counter-traction for the opposite MVR blade while puncturing the capsular bag. Furthermore, the creation of openings in the lens at the equator or just posterior to it is beneficial as the capsule is relatively thicker and stronger at this location. This also minimizes the risk of premature extension to the anterior or posterior capsule, thereby avoiding complications like dropped lens matter, vitreous prolapse, and vitreous traction.

Scleral tunnel with conjunctival autograft for rescue management of extruded haptic: Surgical technique and review of literature.

Extrusion of haptic is a rare complication after intra-scleral haptic fixation of intraocular lens (SF-IOL). Various techniques described for its management such as autologous scleral patch, cauterization of exposed haptic, reattempting the glued IOL and IOL explant have their own limitations. Presently, we describe a simple rescue technique for management of such situations. In this method, after performing localized conjunctival peritomy, 2 mm long partial-thickness scleral tunnel is fashioned with an angled 20-guage microvitreoretinal blade 1.5 mm away from the limbus in line with pre-existing defective scleral flap underneath which the exposed haptic is tucked securely. Following this, conjunctival autograft (CAG) with fibrin glue application is undertaken to combat conjunctival fibrosis. In three patients, where this technique was performed, had well-tucked haptic and maintained visual acuity with no complications at 3-months follow-up. This technique is a useful method of tucking extruded haptic after SFIOL in eyes subjected to multiple previous surgeries.

Preclinical Investigation of Goniotomy Using Four Different Techniques.

PurposeTo evaluate the tissue-level effects of goniotomy techniques on human trabecular meshwork (TM).DesignLaboratory investigation.MethodsThe TM from human cadaveric corneal rim tissue was treated using 4 techniques: (1) microvitreoretinal (MVR) blade; (2) 360° trabeculotomy with 5-0 prolene suture; (3) the Kahook Dual Blade (KDB) Glide® device; (4) TrabEx™ device; tissue samples underwent standard histologic processing with H&E stain followed by comparative analyses.ResultsThe MVR blade exhibited incision of TM extending into the scleral wall. The TrabEx device removed a small portion of TM with large leaflet tissue remnants in all treated areas. 360° suture trabeculotomy resulted in incision of the TM proximate to Schwalbe’s line with no excised tissue evident in all treated areas. Areas treated with the KDB Glide device resulted in nearly complete excision of TM without injury to surrounding tissues.ConclusionThe various methods used for performing goniotomy or trabeculotomy resulted in varying degrees of incision or excision of TM. Only the KDB Glide device resulted in reliable excision of TM with the other devices producing incision or variable excision of tissue. Clinical correlation is required to better understand the implications of the current findings when using these methods to lower intraocular pressure in eyes with glaucoma.

Penetrating Keratoplasty With Sutureless Intrasclerally Fixated Intraocular Lens.

In this retrospective study, we reviewed the use of penetrating keratoplasty with sutureless intrasclerally fixated intraocular lens implantation in a closed anterior chamber in patients with several corneal pathologies and aphakia. The medical records of 6 patients, who underwent the procedure, were reviewed. In the procedure, lamellar scleral tunnels at the 2- and 8-o'clock positions were created with a microvitreoretinal blade, 1.5 mm away from the limbus. Two 27-gauge bent needles were passed, first horizontally, through these tunnels, and then vertically, which allowed them to enter the posterior chamber and to be left in position. Partial thickness trephination was made, and anterior stroma was removed where necessary. An incision was made at the 11-o'clock position, where the trephination was made, which was then extended to both sides for about 6 mm with corneal scissors. From the superior incision, the anterior haptic of a 3-piece intraocular lens was pushed through the needle at the 2-o'clock position, then the posterior haptic was pushed through the needle at the 8-o'clock position, and both haptics were removed through the sclera. Both ends were cauterized and placed into the sclera. Residual stroma was removed, and the donor graft was sutured. At the last follow-up visit, the mean bestcorrected visual acuity was significantly increased. No serious complications were seen, with the exception of increased intraocular pressure in 3 patients. Penetrating keratoplasty with sutureless intrasclerally fixated intraocular lens implantation can be used safely in patients with aphakia. With this technique, the globe stabilization can be maintained, and the trauma to the donor graft endothelium can be minimized.

Sutureless intrascleral fixation of intraocular lens through self-sealing sclerotomy wounds using haptic externalization and reinternalization technique

In eyes with absent or insufficient capsule support, three-piece posterior chamber intraocular lens (PC IOL) may be fixed to the sclera. Previous techniques involve the use of sutures, flaps, glue, needles, trocars, or intrascleral tunnels to fixate the distal tips of the haptics intrasclerally. Herein we describe a modified technique for the sutureless scleral fixation of a standard 3-piece PC IOL using self-sealing sclerotomies created with a crescent blade and a 20-gauge microvitreoretinal blade, and then reinserting the haptics to leave the tips inside the vitreous cavity. We believe the relative simplicity of this technique makes it widely applicable for the placement of an IOL with insufficient capsule support.

Sutureless transscleral fixation of secondary intraocular lenses.

The surgical approach to eyes needing a secondary intraocular lens have evolved rapidly in recent years. Here, we will focus on techniques for scleral-fixation of intraocular lenses (IOLs), and will review the evidence for their safety and efficacy. Transscleral fixation of IOLs refers the placement of lens haptics within scleral tunnels to stabilize the lens in eyes that lack adequate capsular support. Various surgical techniques have been reported recently to accomplish this goal. These include the use of a trocar, microvitreoretinal blade, or hypodermic needle to create the scleral tunnels, as well as several methods for placing the haptics through the tunnels. Although long-term data is lacking, each technique has been shown to have good visual outcomes without significant side effects. Surgical approaches for the transscleral fixation of secondary IOLs provide a safe and effective technique for the management of eyes with insufficient capsular support.

Sutureless biplanar closure of leaking wounds in micro-incision vitreous surgery: A novel technique.

To describe a novel technique for sutureless hermetic closure of leaking scleral wounds in micro-incision vitreous surgery. This study is a two-centre, non-comparative, interventional case series. We studied 1240 scleral incisions on 870 eyes using different gauges (20, 23, 25) to evaluate the effectiveness of a new technique to seal scleral wounds without sutures. If wounds were found leaking after removing the trocar, we used the same trocar (or microvitreoretinal) blade to make an adjacent trans-scleral entry in the same direction as the main incision to access its internal flap supporting it from inside. Simultaneously, we applied a blunt smooth-surface instrument to massage the scleral wound from outside to close it hermetically. We treated 870 eyes using three types of tamponading agents, namely, silicone oil in 654 (75%) eyes, non-expansible gas in 128 (15%) eyes, and air in 88 (10%) eyes. We performed optical coherence tomography in the first 100 sclerotomies on the post-operative Day 1. We closed leaking incisions at the first attempt in 1231 (99.3%) cases; in 9 (0.7%) cases of 20-gauge incisions, we closed the wounds at the second attempt. We observed no hypotony at the end of surgery. The mean intraocular pressure was 16 mmHg (8-51 mmHg) on the post-operative Day 1. Our results show the biplanar closure technique may be used as an effective, quick, sutureless approach to close leaking wounds hermetically in micro-incision vitreous surgery procedures. It is safe, less traumatic, cost-effective, and easy-to-perform typical surgical settings.

Update on Microinvasive Glaucoma Surgery.

Update on Microinvasive Glaucoma Surgery.

Management of late-onset flocculent after-cataract with capsular bag lavage and posterior continuous curvilinear capsulorhexis.

We describe our technique for the management of late-onset liquefied after-cataract (LAC) to ensure long-term visual axis clarity. The densely adherent anterior capsular rim over the intraocular lens (IOL) optic was released with the help of microvitreoretinal blade, and multiple relaxing radial incisions were made on the capsular rim to facilitate easy access to the capsular bag. A thorough capsular bag lavage was performed with the help of bimanual irrigation-aspiration. Posterior continuous curvilinear capsulorhexis (PCCC) was performed after complete aspiration of fluid after-cataract to prevent recurrence. This technique was successfully performed in 14 cases. Postoperatively, IOL was stable and an uncorrected distance visual acuity of >20/32 was achieved in all cases. No recurrence was observed in any case over a follow-up of 1 year. Our technique of capsular bag lavage with PCCC is safe and effective for the management of LAC with optimal visual and anatomical outcomes.

Anterior segment approach for the surgical management of aqueous misdirection syndrome

We describe the surgical management of the aqueous misdirection syndrome through clear corneal incisions. A 20-gauge microvitreoretinal blade is used to create 2 side-port incisions. The same blade is inserted through the cornea and the iris for the main incision; it is then directed toward the center of the eyeball, passing through the zonular fibers to the vitreous cavity behind the pupil. Irrigation is delivered to the anterior chamber, the vitrector is placed in the vitreous cavity, and vitrectomy is performed. With this technique, aqueous misdirection can be resolved and adequate IOP control achieved.

Implantation of trabecular micro-bypass stent using a novel "landing strip" technique.

To describe a novel technique of creating a landing strip within the trabecular meshwork to guide trabecular micro-bypass stent (iStent) implantation in patients who underwent phacoemulsification. Thirty-four eyes from 30 patients who underwent iStent implantation after phacoemulsification from May 2014 to February 2015 were included in our retrospective study. All iStents were implanted via the "landing strip" technique. A 25-gauge microvitreoretinal blade was used to bisect the trabecular meshwork to less than 1 clock-hour, effectively creating a landing strip. The iStent applicator was pressed along the landing strip and then the stent was released into the trabecular meshwork. Of the 34 eyes with iStent implantation, 27 (79.4%) eyes had primary open-angle glaucoma, 6 (17.6%) eyes had pseudoexfoliation glaucoma, and 1 (2.9%) eye had ocular hypertension. At 6-month follow-up (n=17), the mean number of hypotensive medications decreased from 2.2±1.2 at baseline to 0.8±1.3 (P=0.05) and mean intraocular pressure decreased from 19.7±4.1 mm Hg at baseline to 16.7±2.1 mm Hg (P=0.58). Two eyes (5.9%) required subsequent trabeculectomy. The "landing strip" technique appears to be an effective way to assist with iStent implantation.

Transconjunctival Revision With Mitomycin-C Following Failed Trabeculectomy

To evaluate the efficacy of transconjunctival revision (TCR) with mitomycin-C (MMC) following failed trabeculectomy. The medical records of 27 patients (27 eyes) who underwent TCR with subconjunctival injection of MMC by a single surgeon between September 2001 and August 2013 were retrospectively reviewed. The same surgical protocol was followed for all patients. Revision was performed using a microvitreoretinal blade through a small conjunctival incision. Main outcome measures included visual acuity, intraocular pressure (IOP), and number of glaucoma medications. Failure was defined as an IOP<5 or >14 mm Hg, loss of light perception, or need for additional glaucoma surgery. Mean interval between trabeculectomy and TCR was 56.4±57.2 months. Mean preoperative IOP was 21.9±6.8 mm Hg using 4.0±1.2 glaucoma medications. Fifteen (55.6%) patients met success criteria. At most recent follow-up, mean IOP and number of glaucoma medications for successful patients were 9.7±3.8 mm Hg and 0.6±1.1, respectively. Kaplan-Meier analysis revealed 1-, 2-, and 3-year success rates of 62%, 58%, and 53%, respectively. Three additional patients achieved success after undergoing a second TCR, and 1 patient achieved success after a third TCR. Postoperative complications included transient choroidal effusion (n=8), shallow anterior chamber requiring reformation (n=5), 5-fluorouracil-related corneal epitheliopathy (n=10), and bleb leak (n=1). TCR with adjunctive MMC is a safe and effective procedure following failure of a trabeculectomy. More than 1 revision may be necessary to achieve long-term IOP reduction.

Injectable suture device for intraocular lens fixation

We describe a surgical technique for scleral fixation of a posterior chamber intraocular lens (PC IOL) using a 24-gauge injectable polypropylene suture delivery system. A 3-piece PC IOL is inserted into the anterior chamber of the eye. Two sclerotomies are made 1.5 mm posterior to the limbus using a microvitreoretinal blade. The 24-gauge injector delivers a preformed suture loop into the eye with the double-armed needles still external to the eye. Each polypropylene IOL haptic is directed through the loop using microforceps. The suture loop is tightened around the haptic, and the attached needles are used to fixate the IOL to the sclera and close the sclerotomies simultaneously. This technique has been used in an ex vivo porcine eye and in an aphakic patient. In the latter, the IOL was quickly fixated to the sclera and maintained a stable position postoperatively. Dr. Olson has a patent pending for the device described in this article. No other author has a financial or proprietary interest in any material or method mentioned.

Sutureless scleral fixation of intraocular lenses: outcomes of two approaches. The 2014 Yasuo Tano Memorial Lecture.

We sought to assess the clinical outcomes and complications of two approaches to scleral fixation of intraocular lenses (IOLs): transconjunctival fixation through trocar cannulas and fixation using scleral tunnels created with a microvitreoretinal (MVR) blade. This retrospective chart review was comprised of 23 eyes that received scleral fixation of a three-piece IOL with concurrent pars plana vitrectomy between June 2012 and June 2014. Scleral fixation was performed either by transconjunctival fixation through trocar cannulas (cannula fixation) or by the creation of scleral tunnels using an MVR blade (tunnel fixation). The preoperative and postoperative corrected distance visual acuities (CDVA), spherical equivalents (SE), and complications were evaluated. 15 cannula fixations and 8 tunnel fixations were performed. Mean follow-up was 353 days (Range: 94 - 790 days). Fifteen IOLs were fixated 2 mm posterior to the limbus. Seven IOLs were fixated 1.5 mm posterior to the limbus, and one IOL was fixated 0.75 mm posterior to the limbus. Mean preoperative CDVA was logMAR 1.17 (Snellen 20/297), and mean postoperative CDVA was logMAR 0.37 (Snellen 20/47) (p <0.0001). At last follow-up, none of the IOLs have dislocated or subluxed and there has been no erosion of the subconjunctival haptics. Scleral fixation of IOLs using trocar cannulas or scleral tunnels is an effective surgical option for the treatment of aphakia or IOL dislocation. Both techniques result in significant visual improvement with minimal postoperative complications.

Comparison of the effects of 23-gauge and 25-gauge microincision vitrectomy blade designs on incision architecture.

PurposeTo compare the effects of different 23- and 25-gauge microincision vitrectomy trocar cannula entry systems on incision architecture.MethodsWe tested one ridged microvitreoretinal (MVR), one non-ridged MVR, one pointed beveled, and one round-tipped beveled blade (n=10 per blade design per incision type). Each blade’s straight and oblique incision architecture was assessed in a silicone disc simulating the sclera. Wound leakage under pressure and endoscopic observations were conducted on sclerotomy sites of isolated porcine eyes (n=4 per blade design) after simulated vitrectomy.ResultsDifferences in blade design created distinct incision architecture. Incisions were linear with the ridged MVR blade, flattened “M-shaped” with the non-ridged MVR blade, asymmetrical chevron-shaped with the pointed beveled blade, and curved with the round-tipped beveled blade. With the exception of oblique entry incision thickness, both MVR blade designs created thinner incisions than the beveled blades at entry and exit sites. Only the ridged MVR blade created incisions with no leakage. Vitreous incarceration was observed with all trocar cannula systems.ConclusionWound closure in porcine eyes was similar with all blades despite differences in incision architecture. Wound leakage occurred at low to moderate infusion pressures with most blades; no wound leakage was observed with ridged MVR blades.

Learning curve of sutureless transconjunctival 20-gauge vitrectomy.

BackgroundTo report the learning curve of transition from 20-gauge (20 G) conventional vitrectomy to a 20 G sutureless vitrectomy technique.Materials and methodsThis is a retrospective descriptive case study of 32 eyes from 32 consecutive patients who underwent sutureless 20 G pars plana vitrectomy. A 20 G microvitreoretinal blade was introduced, beveled transconjunctivally, slowly, parallel with the limbus, creating a conjunctivoscleral tunnel incision. Study participants were divided into three groups, and surgical time, induced astigmatism, and complications were compared.ResultsOf 32 consecutive patients, there was no significant difference in induced astigmatism or maneuvering between the early learning curve and other groups. The true learning curve was the first three patients. There were three cases where suturing the sclerotomy was necessary: one port in each case, three of 32 cases (9.3%), or three of 96 ports (2.9%).ConclusionThere were no significant difficulties in surgical maneuvers while performing 20 g sutureless vitrectomy.

A reasonable option in vitrectomized eyes: manual small incision cataract surgery.

Dear Sir,It is known that cataract surgery is challenging in vitrectomized eyes.Cataract surgeons may have encountered with posterior capsular complications and nucleus drop events even with minimal ocular manipulations and low irrigation bottle height.Inadvertent damage to the zonular fibers,posterior or peripheral lens capsule with ocutome or microvitreoretinal(MVR)blade in previous

Surgical iridotomy in aphakic eyes and eyes with anterior chamber intraocular lenses

We describe a simple technique to create a peripheral surgical iridotomy using a microvitreoretinal blade. The blade passes perpendicular to the iris dilator fibers to create a permanent opening. No author has a financial or proprietary interest in any material or method mentioned.

Three years results of modified self-sealing sclerotomies for twenty-gauge pars plana vitrectomy

Objective To evaluate the safety and effectiveness of 1.2mm self-sealing sutureless sclerotomy in twenty-gauge pars plana vitrectomy.Methods This is a retrospective study.We shortened the two superior scleral tunnels to 1.2 mm,then perforation was performed at the end of the tunnels and the sclera was pierced perpendicularly with a microvitreoretinal (MVR)blade through the scleral tunnel.After that,the inferotemporal incision for infusion was performed in a classic way with a MVR knife.This modified technique was applied to 511 patients that received phaco combined primary pars plana vitrectomy or primary pars plana vitrectomy from March 2006 to Decemnber 2008.Results There were 511 cases (511 eyes) included from March 2006 to December 2008.Among them there were 281 males with 281 eyes,230 females with 230 eyes,ranging from 18 to 93 years old,averaged 53.4 ± 13.4.There were 348 cases (348 eyes) of retinal detachment,92 cases (92 eyes) of diabetic retinopathy,and 71 cases (71 eyes) of others.In 2006,from March to December,171 of 198 sclerotomies (86.4％) among 99 patients did not require suturing.In 2007,320 of 356(89.9％) sclerotomies among 178 patients were sutureless.In 2008,427 of 468 sclerotomies (91.2％) among 234 patients were self-sealing.None of the incision-related complications needed further intervention.No gas or silicone oil leakage was observed.From 2009 till now,the selfsealing rate was still higher than 80％ even the operation was performed by junior doctors.Conclusion Modified self-sealing sutureless sclerotomy is safe and convenient.It is particularly suitable for patients with narrow palpebral fissures.The self-sealing rate can also be increased with the improvement of surgical skill. Key words: Tunnel, scelral ; Self-sealing, modified ; Vitrectomy