Efficacy and safety evaluation of Monoblue Dual View and Monoblue ILM View vital stains during vitrectomy surgery.

PURPOSE: To compare the staining properties of Monoblue inner limiting membrane (ILM) View and Monoblue DUAL View (study products) vital stains during vitrectomy surgery to those of ILM Blue or Membrane Blue Dual (control products). METHODS: In this study, 105 patients were included in the Ophthalmic Clinic of the University Hospitals Leuven from September 2021 to April 2022. For prospective data collection in this study, patients were randomized between a control group (ILM Blue or Membrane Blue Dual, manufactured and commercialized by DORC®) and a study group (Monoblue ILM View or Monoblue DUAL View, manufactured and commercialized by Arcadophta®-BVI®). For retrospective data collection, patients were divided into similar surgery groups. Efficacy was analyzed using a binary subjective evaluation of the visualization of stained membranes during vitrectomy. The rate and severity of potential adverse events related to the study products were tracked, allowing both treatment groups to be compared with the corresponding control groups (ILM Blue and Membrane Blue Dual). RESULTS: Based on the results and findings, none of the comparisons (primary outcomes) were statistically significant, showing similar efficacy of the dyes used. The study products were found to be safe in this study since no serious adverse events were reported. CONCLUSIONS: The present findings indicate that the Monoblue ILM View and Monoblue DUAL View dyes can safely be used during vitrectomy to stain the ILM and/or epiretinal membrane (ERM) when removal is needed.

Efficacy and safety of the implantation of a single-piece angulated foldable IOL in the sulcus.

PURPOSE: To study the visual results and tolerance of a Zeiss CT Lucia 601P intraocular lens (IOL) implanted in the sulcus after complicated cataract surgery or during IOL exchange for clouded IOL. METHODS: In total, 64 patients who underwent sulcus implantation were recalled to the hospital to undergo subjective and objective refraction, best corrected visual acuity measurement, tonometry, optical coherence tomography, laser flare photometry, biometry, and wavefront aberrometry. RESULTS: In spite of a large variation in preoperative refraction, the target refraction was obtained within 1.5 diopters in approximately 97% of patients and within 0.5 diopter in 53% of patients. Average BCVA was high (Snellen 0.86) and related to concomitant (mostly retinal) pathologies in eyes with poorer visual performance. Wavefront aberrometry showed no evidence of IOL tilting or decentration after long-term implantation in the sulcus. Tonometry was not different from the fellow eye of the patient (p > 0.5). In 53 patients with bilateral pseudophakia, the laser flare photometry was not significantly different from the fellow eye (p < 0.05). CONCLUSION: This study demonstrates that this single-piece angulated foldable acrylic IOL can be considered for implantation in the sulcus. The visual results are favorable, and the IOL can be well-positioned and tolerated in the sulcus. Moreover, there were no safety issues found since there was no evidence of elevated IOP or chronic uveitis.

Patient satisfaction after EDOF intraocular lens implantation in vitrectomized eyes.

PURPOSE: To report patient satisfaction after unilateral/bilateral extended depth-of-focus (EDOF) intraocular lens (IOL) implantation in a young population after vitrectomy. METHODS: Patients that underwent phaco-vitrectomy or phaco following vitrectomy with an AT LARA EDOF IOL, aged between 18 and 75 years, were asked to fill out a questionnaire to assess overall visual quality, near vision quality, and visual disturbances. The questionnaire was based on the Catquest, NAVQ, and APPLES questionnaires. RESULTS: A total of 89 participants (average age 56.7 years) filled out the questionnaire of which 53.9% received a unilateral EDOF IOL. The most common indications for vitrectomy were retinal detachments (38.2%), floaters (36.0%), and epiretinal membranes (16.9%). The Catquest and NAVQ score respectively showed a good overall satisfaction (3.44/4.0), a good intermediate vision (3.55/4.0), and an average near vision (2.75/4.0). The APPLES score showed acceptable visual disturbances. There were no differences between the unilateral and bilateral group, except for a higher spectacle dependency in the unilateral group (40% vs. 10.6%). Participants that underwent vitrectomy in case of floaters reported lower satisfaction rates. Other variables, like the pre-operative refraction, had no impact on both satisfaction and visual disturbances. CONCLUSION: Both unilateral and bilateral implantation of the AT LARA EDOF IOL showed a high satisfaction with no differences between both groups, except for a lower spectacle use in the latter. Hence, The AT LARA seems to be a possible choice in patients undergoing vitrectomy at a younger age, even for unilateral use.

Investigation of the effectiveness of a new portable 'cryopen' probe for cryotherapy (CryoTreq®).

BACKGROUND: To test the effectiveness of a new, innovative, single-use handheld 'cryopen' (CryoTreq®), which has been developed and marketed by Vitreq. METHODS: Animal testing of cryopexy using the Cryotreq ® in two pig eyes was performed. RESULTS: The biological effects of cryopexy were observed. CONCLUSIONS: During the surgery, the handheld device was comfortable to use and offers the surgeon more freedom to move. The cryotherapy caused severe atrophy and thinning of retinal layers, pigment epithelium and choroidea in a relatively uniform thickness. The cryopen is effective and offers advantages over non-handheld cryotherapy devices.

A Comparative Study of 23-Gauge and 27-Gauge Vitrectomy for Puckers or Floaters, Including Evaluation of the Effect of Combined Phaco-Vitrectomy Surgery on Postoperative Outcome.

INTRODUCTION: A single-center, prospective randomized comparison of postoperative recovery between 23-gauge and 27-gauge surgical approaches in vitrectomy was performed. METHODS: A single-center, prospective randomized comparison of postoperative recovery between 23-gauge and 27-gauge surgical approaches to evaluate efficiencies and postoperative outcomes of the two surgical gauges. Eighty patients who were scheduled to undergo pars plana vitrectomy (PPV) for floaters or macular surgery were treated with either 27-gauge or 23-gauge techniques and assessed for efficiency of the procedures as well as a variety of postop indicators of pain and inflammation. RESULTS: 27-Gauge vitrectomy took 90 s more time compared to 23-gauge surgery. Wound closure was significantly easier in 27-gauge than 23-gauge. Less postoperative eye reddishness was seen in 27-gauge compared to 23-gauge. A trend towards less inflammation was seen in 27-gauge. CONCLUSION: Overall, the trial showed that 27-gauge has the better postoperative outcome compared to 23-gauge PPV. Combining vitrectomy with phaco-surgery did not influence the study outcome parameters.

Effectiveness of immediate vitrectomy and intravitreal antibiotics for post-injection endophthalmitis.

PURPOSE: To show that an immediate vitrectomy with an intravitreal injection of antibiotics can be an effective approach for the treatment of acute endophthalmitis following intravitreal injections. METHODS: We reviewed all cases of clinical endophthalmitis caused by an intravitreal injection that were treated in our department between March 2012 and November 2019. Only patients that underwent a vitrectomy within 6 h after presentation to the clinic and with a documented visual acuity shortly before the causative event were included. Baseline best-corrected visual acuity (BCVA) before the causative event was compared to BCVA measured within a follow-up period of 8 months (up to 14 months). RESULTS: In total, 30 eyes of 30 patients were included. The BCVA before the intraocular infection was a mean value of 0.55 logMAR, and the BCVA on the day of the endophthalmitis decreased significantly to 1.66 logMAR. Within 2 months following the pars plana vitrectomy (PPV), the mean BCVA improved to 0.83 logMAR. Eight months following PPV (mean value, 8.20 months; SD, 3.59 months), the mean BCVA was 0.63 logMAR. In the last follow-up interval most of the eyes recovered, and the BCVA did not differ significantly from baseline. Two eyes underwent further pars plana surgery during the follow-up period. No enucleation was required. CONCLUSION: In this study, we have shown that an immediate vitrectomy with subsequent intravitreal injection of antibiotics is an effective option for treating post-injection endophthalmitis and frequently results in recovery of vision; thus, it should be performed as early as possible, where available.

Phase I trial on robot assisted retinal vein cannulation with ocriplasmin infusion for central retinal vein occlusion.

PURPOSE: To evaluate the safety and feasibility of robot-assisted retinal vein cannulation with Ocriplasmin infusion for central retinal vein occlusion. METHODS: Prospective phase I trial including four patients suffering from central retinal vein occlusion (CRVO). Diagnosis was confirmed by preoperative fluo-angiography and followed by a standard three-port pars plana vitrectomy. Afterwards, a custom-built microneedle was inserted into a branch retinal vein with robotic assistance and infusion of Ocriplasmin started. Primary outcomes were the occurrence of intra-operative complications and success of cannulation. Secondary outcomes were change in visual acuity, central macular thickness (CMT) and venous filling times (VFT) during fluo-angiography two weeks after the intervention. RESULTS: Cannulation with infusion of ocriplasmin was successful in all four eyes with a mean total infusion time of 355 ± 204 seconds (range 120-600 seconds). Best corrected visual acuity (BCVA) remained counting fingers (CF) in case 3 and 4, increased in case 1 from CF to 0.9LogMAR and decreased in case 2 from 0.4 to 1.3 LogMAR. CMT and VFT both showed a trend towards significant decrease comparing preoperative measurements with two weeks postintervention (1061 ± 541 µm versus 477 ± 376 µm, p = 0.068) and 24 ll 4 seconds versus 15 ± 1 seconds, p = 0.068, respectively). In one eye a needle tip broke and could be removed with an endoforceps. There were no other intervention-related complications. CONCLUSION: Robot-assisted retinal vein cannulation is feasible and safe. Local intravenous infusion with Ocriplasmin led to an improved retinal circulation.

Visual Outcome after Vitrectomy with Subretinal tPA Injection to Treat Submacular Hemorrhage Secondary to Age-Related Macular Degeneration or Macroaneurysm.

PURPOSE: To determine the efficacy and safety of 23G transconjunctival sutureless vitrectomy, subretinal injection of tissue plasminogen activator using the EVA Surgical System, and pneumatic displacement with air to treat submacular hemorrhages. METHODS: Retrospective analysis of 93 eyes surgically treated for submacular hemorrhage caused by neovascular AMD or retinal macroaneurysms. Main Outcome Measures. Postoperative visual acuity and surgical complications. RESULTS: After surgery, visual acuity improved after 6 weeks but decreased again at the final postoperative visit at 8 months due to progression of the underlying disease. Complications consisted of 2 cases of retinal pigment epithelial tear, 7 vitreous hemorrhages, 4 hyphema, 6 cases of retinal detachment, and 2 subchoroidal hemorrhages during the follow-up period. CONCLUSIONS: This study suggests that a surgical approach with 23G vitrectomy, subretinal tPA injection, and pneumatic displacement using air may be an effective procedure for submacular hemorrhage displacement in patients with AMD and retinal macroaneurysms. However, visual outcome is limited by the underlying macular pathology. Larger multicenter randomized controlled studies are warranted to determine the therapeutic effect of this surgical approach.

A Retrospective Case Series of Uveal Effusion Syndrome.

PURPOSE: This study aimed to describe the clinical findings and management of eyes affected by uveal effusion syndrome. METHODS: We retrospectively evaluated the charts of 13 eyes of 8 consecutive patients diagnosed with uveal effusion syndrome attending the Ophthalmology Unit of the University Hospitals Leuven, Belgium, between 2007 and 2018. The presenting features, investigations, management, and outcomes were analyzed for each case. RESULTS: Cataract surgery was the predisposing factor for uveal effusion in 6 eyes, 2 bilateral uveal effusions (4 eyes) were considered to be medication-induced, and in 3 eyes, the uveal effusion was described as idiopathic. Fundus examination of 5 of 13 eyes showed bullous choroidal detachment, treated with pars plana vitrectomy with superotemporal sclerectomy or transscleral punction. Fundoscopy showed uveal effusion without serous retinal detachment in 3 eyes. Serous retinal detachment accompanied by uveal swelling was observed in 3 eyes and the 2 remaining eyes presented with uveal swelling only. The 8 nonbullous choroidal detachments were treated in a conservative way. A rapid resolution of subretinal fluid and uveal effusion was observed in all cases. CONCLUSIONS: A conservative approach with acetazolamide treatment or just observation was used in our case series in choroidal detachment without substantial visual loss if, over time, slow improvement was documented. However, further studies are needed to verify the effectiveness of the reported therapy.

ASSESSMENT OF ANATOMICAL AND FUNCTIONAL OUTCOMES WITH OCRIPLASMIN TREATMENT IN PATIENTS WITH VITREOMACULAR TRACTION WITH OR WITHOUT MACULAR HOLES: Results of OVIID-1 Trial.

PURPOSE: To evaluate the anatomical and functional outcomes with ocriplasmin in patients with vitreomacular traction (VMT) with or without macular hole (MH). METHODS: In a Phase 4, multicenter, single-arm, open-label study, eligible patients (VMT with focal adhesion, without epiretinal membrane, and with MH ≤400 µm [if present]) received a single intravitreal injection of ocriplasmin. Nonsurgical resolution of VMT (Day 28 [primary endpoint]), best-corrected visual acuity, MH closure, vitrectomy rate, and safety were assessed through Day 180. RESULTS: Overall, 466 patients were included in the full analysis set, of whom 47.4% had VMT resolution by Day 28; resolution rates in patients with VMT without MH, VMT with MH ≤250 µm, and VMT with MH >250 to ≤400 µm were 43.4%, 68.6%, and 62.7%, respectively. Macular hole closure was higher in eyes with VMT and MH ≤250 µm (57.1%) than in eyes with VMT and MH >250 to ≤400 µm (27.5%) at Day 28. Overall, 30.8% of patients with VMT resolution gained ≥10 letters in best-corrected visual acuity at Day 180. Adverse events were consistent with the known safety profile of ocriplasmin. CONCLUSION: Ocriplasmin is effective for resolution of VMT without or with MH (≤400 µm); treatment outcomes can be optimized with patient selection.

The vitreopapillary interface in healthy and glaucoma: posterior vitreous detachment in the vitreopapillary interface study.

PURPOSE: To investigate the vitreopapillary interface (VPI) in health and glaucoma according to the different stages of posterior vitreous detachment (PVD) formation. METHODS: Prospective single centre study including healthy subjects and glaucoma patients. PVD staging was performed with spectral domain optical coherence tomography. Gender, age, lens status and refractive error were assessed in both groups. Glaucoma patients additionally had a comprehensive ophthalmological investigation including intraocular pressure measurement, visual field testing and confocal imaging of the optic nerve head. RESULTS: Data on 523 subjects (993 eyes) were included from the VPI study (clinicaltrials.gov NCT02290795) database (493 eyes of 258 healthy subjects and 500 eyes of 265 glaucoma patients). Healthy subjects were significantly younger than primary open angle glaucoma patients (59.7 ± 14.81 versus 70.0 ± 10.78 years, p < 0.001), but were otherwise matched for refractive error and gender. Significantly more glaucomatous eyes were pseudophakic (26.6% versus 5.1%). Including only phakic nonoperated eyes from subjects between 50 and 80 years old decreased the age difference between healthy and open angle glaucoma (64.1 ± 8.0 versus 65.9 ± 6.7 years, p = 0.051). Comparing these subgroups rendered similar average ages for PVD stages 0 and 4, in contrast to the significant older age for the glaucoma subgroup in stage 1 (64.1 ± 6.01 versus 61.4 ± 8.38 years, p < 0.001) and a trend towards significance in stage 3 (70.8 ± 69.8 versus 67.5 ± 5.92 years, p = 0.051). CONCLUSION: The VPI study is a large clinical trial investigating the VPI in health and glaucoma. A subset of glaucoma patients seems to experience stages 1-3 of PVD formation at older age compared to healthy subjects.

Retinal Toxicity of Medical Devices Used during Vitreoretinal Surgery: A Critical Overview.

Retinal toxicity/biocompatibility of medical devices in direct contact with the retina is an important subject for clinicians and scientists. As these effects are not very frequent, there is also a relative lack of information for many clinicians. The past has taught us multiple times that there is a significant safety problem associated with severe loss of vision in affected patients. In this review, we want to classify medical products that are used in the back of the eye, describe recent examples of toxicity, critically reflect on the regulations that exist and suggest improvements that can be done to ensure patient safety without hindering innovation. METHODS: Critical review of the recent papers and personal experience of the authors in this issue. Medical devices used in the back of the eye and recent examples of toxicity are described, regulations that exist are critically reflected and improvements suggested that can ensure patient safety without hindering innovation. RESULTS: There is clear evidence of toxicity after intraocular surgery in any category. Some cytotoxic indirect methods have failed in detecting this toxicity. Some ISO rules do not seem appropriate. Postmarketing safety is missing. There is little data on this issue. CONCLUSIONS: The absence of a clear regulation of the production, purification and evaluation of the toxic effects of the medical devices supposes the possibility that products are not sufficiently safe to obtain the CE mark.

In-Human Robot-Assisted Retinal Vein Cannulation, A World First.

Retinal Vein Occlusion (RVO) is a blinding disease caused by one or more occluded retinal veins. Current treatment methods only focus on symptom mitigation rather than targeting a solution for the root cause of the disorder. Retinal vein cannulation is an experimental eye surgical procedure which could potentially cure RVO. Its goal is to dissolve the occlusion by injecting an anticoagulant directly into the blocked vein. Given the scale and the fragility of retinal veins on one end and surgeons' limited positioning precision on the other, performing this procedure manually is considered to be too risky. The authors have been developing robotic devices and instruments to assist surgeons in performing this therapy in a safe and successful manner. This work reports on the clinical translation of the technology, resulting in the world-first in-human robot-assisted retinal vein cannulation. Four RVO patients have been treated with the technology in the context of a phase I clinical trial. The results show that it is technically feasible to safely inject an anticoagulant into a [Formula: see text]-thick retinal vein of an RVO patient for a period of 10 min with the aid of the presented robotic technology and instrumentation.

The role of the vitreous body in effective IOL positioning.

PURPOSE: To compare the effective lens position (ELP) after phaco surgery alone and after combined phacovitrectomy surgery. METHODS: Twenty patients who were scheduled for elective surgery in both eyes were included. In one eye, phacovitrectomy surgery was performed (without any tamponade), and in the fellow eye, only phaco surgery was performed using the same IOL type. Pre- and postoperative biometric measurements were performed using laser interference biometry. The postoperative anterior chamber depth (ACD) was measured to determine the ELP. The primary outcome measure was the difference in the postoperative ACD between both eyes. RESULTS: The postoperative ACD following phacovitrectomy showed a statistically significant increase compared with that following phaco surgery alone, indicating a more posterior position of the IOL. CONCLUSIONS: An adjusted ELP parameter to optimize IOL calculation may be useful in eyes undergoing combined phacovitrectomy sugergy.

Tracking posttraumatic hemianopia.

Hemianopia after traumatic brain injury is not infrequent and results from retro-chiasmatic lesions. Differentiating optic pathway lesions can be challenging with classic imaging. Advanced imaging techniques as an investigational tool for posttraumatic hemianopia are discussed and their pitfalls highlighted through an illustrative case study. In a patient with posttraumatic hemianopia, MRI at 8 weeks and 2 years after trauma were analyzed. Diffusion tensor imaging (DTI) and morphometric analysis of the primary visual cortex (V1) were performed. Optical coherence tomography (OCT) was performed 2 years after trauma. DTI at 8 weeks showed a decrease in fractional anisotropy (FA) of the left optic tract together with a decrease in FA in the right optic tract and optic radiation. At 2 years, an isolated decrease of the left optic tract FA values was noticed together with signs of Wallerian degeneration on classic MR imaging. OCT showed thinning of the retina congruent with the visual field deficit. While DTI abnormalities were also present in the early scan, they were more diffuse and also encompassed functionally intact structures. Results of advanced imaging techniques need to be interpreted with caution and can vary according to the timing of imaging due to Wallerian degeneration.

Prevalencia de alteraciones en la interfase vitreoretiniana detectadas mediante tomografía de coherencia óptica de dominio espectral.

Objetivo: El objetivo principal del presente estudio consistió en determinar la prevalencia de los cambios en la interfase vitreomacular (IVM) mediante tomografía de coherencia óptica (OCT) en la población general. En segundo lugar, se describieron otros cambios de la OCT. Métodos: Las anomalías en la IVM se diagnosticaron mediante OCT y se distribuyeron de acuerdo con la clasificación del grupo International Vitreomacular Traction Study (estudio internacional de tracción vitreomacular, IVTS, por sus siglas en inglés) y se dividieron en 3 grados según John et al. [Retina 2014;34:442-446]. Resultados: La prevalencia calculada de anomalías vitreomaculares en la población belga de ≥50 años fue del 1,17% [intervalo de confianza (IC 0,38-3,62)] en el caso de tracción vitreomacular (TVM) focal de grado 1; del 0,39% (IC 0,05-2,76) en el caso de TVM focal de grado 2; del 8,17% (IC 5,33-12,53) en el caso de adhesión vitreomacular focal; y del 17,9% (IC 13,41-23,9) en el caso de adhesión vitreomacular difusa. Conclusiones: Se presentó la prevalencia de anomalías vitreomaculares en un estudio de cohortes belga. Estos resultados concuerdan en gran medida con los datos presentados previamente sobre la prevalencia de la TVM. Un conocimiento correcto sobre la epidemiología de las alteraciones en la IVM y un diagnóstico temprano permitirán una intervención satisfactoria.

Optical Coherence Tomography Angiography of Retinal Microvascular Changes Overlying Choroidal Nodules in Neurofibromatosis Type 1.

PURPOSE: To report 3 cases of neurofibromatosis type 1 (NF1) with choroidal nodules associated with retinal microvascular changes imaged with optical coherence tomography angiography (OCTA). METHODS: Small case series in 3 NF1 patients. OCTA examinations were performed by a trained examiner (J.J.) after pupillary dilation. A standard scan, centered over the macula measuring 6 × 6 mm and 3 × 3 mm was obtained according to the findings on standard color photography. Additional scans were obtained in the zones with microvascular abnormalities. The segmentation provided by the machine software was used. RESULTS: Corkscrew retinal vessels were observed in association with "placoid"-type choroidal nodules as shown by near-infrared reflectance imaging. In all cases, multiple lesions were found. They were second- or third-order tortuous vessels originating from the superior or inferior temporal veins. OCTA demonstrated that the tortuous venules were located in the superficial capillary plexus, and no abnormalities were found in the deep capillary plexus. DISCUSSION: Corkscrew retinal vessels are part of a spectrum of retinal microvascular alterations seen in association, sometimes overlying choroidal nodules in patients with NF1 and are visualized in the superficial capillary plexus on OCTA. We demonstrated with OCTA that they are not associated with flow loss or ischemia in the superficial and deep capillary plexus. The link between the underlying nodule remains unclear. Since neovascularization was described in choroidal ganglioneuroma, we hypothesize that corresponding secretory substances from Schwann cells, ganglion cells, or melanocytes in choroidal nodules might alter the retinal vasculature. CONCLUSION: We report on 3 cases of NF1 with choroidal nodules in association with retinal microvascular changes imaged with OCTA. OCTA demonstrated preservation of the blood flow in the deep and superficial capillary plexus of the retina. We hypothesize that angiogenic factors secreted by the underlying choroidal nodules could have an effect on the retinal vasculature. Further immunohistological studies in NF1 patients with choroidal nodules to detect angiogenic factors (such as VEGF) are necessary to confirm this hypothesis.

Intravitreally Injected Fluid Dispersion: Importance of Injection Technique.

Purpose: The purpose of this study was to evaluate the dispersion of intravitreally injected solutions and investigate the influence of varying injection techniques. Methods: This was a prospective study using enucleated porcine eyes and ultra-high-resolution computed tomography (UHRCT) scanning to visualize iomeprol intravitreal dispersion. Sixty eyes were divided over 12 different groups according to the injection procedure: fast (2 seconds) or slow (10 seconds) injection speed and needle tip location (6- and 12-mm needle shaft insertion or premacular tip placement verified by indirect ophthalmoscopy). For each of these combinations, eyes were either injected with the combination of V20I (which is an analogue of ocriplasmin) and iomeprol or iomeprol alone. Distance to the macula and volume measurements were performed at 1, 2, 3, and 5 hours after injection. Results: The measured contrast bolus volume increases slowly over time to an average of 0.70 (P = 0.03), 1.04 (P = 0.006), and 0.79 (P = 0.0001) cm3 5 hours after the injection for the 6-mm needle shaft insertion, 12-mm needle shaft insertion, and premacular needle tip placement, respectively. The distance to the macular marker was significantly lower for premacular needle tip placement injections compared with 6- and 12-mm needle shaft insertion depths. Conclusions: Ultra-high-resolution computed tomography with three-dimensional reconstruction offers the possibility to study the dispersion of intravitreally injected solutions in a noninvasive manner. Intravitreal premacular solution delivery is possible with an indirect ophthalmoscope-guided injection technique and significantly reduces the time to reach the posterior pole in respect to 6- and 12-mm needle insertion depths. The speed of injection does not influence dispersion significantly.

Robot-assisted retinal vein cannulation in an in vivo porcine retinal vein occlusion model.

PURPOSE: To evaluate the feasibility of robot-assisted retinal vein cannulation for retinal vein occlusion. METHODS: Prospective experimental study performed in in vivo porcine eyes. A standard three port pars plana vitrectomy was followed by laser-induced branch retinal vein occlusion. Consequently, a retinal vein cannulation with the help of a surgical robot and a microneedle was performed. Complete success was defined as a stable intravenous position of the needle tip confirmed by blood washout for at least 3 min. Secondary outcomes were the occurrence of intra-operative complications and technical failures. RESULTS: Cannulation was successful in 15 of 18 eyes with a complete success rate (duration of infusion of more than 3 min) of 73% after exclusion of two eyes from analysis due to failure in establishing a blood clot. There were no technical failures regarding the robotic device. The intravessel injections of ocriplasmin in two of two eyes led to a clot dissolution. In a subset of five eyes, a second cannulation attempt at the border of the optic disc resulted in a stable intravessel position and infusion during 362 (±138) seconds. CONCLUSION: Robot-assisted retinal vein cannulation with prolonged infusion time is technically feasible. Human experiments are required to analyse the clinical benefit of this new therapy.