Advances in management strategies for large and persistent macular hole: An update

The standard of care to treat small- and medium-sized macular holes (<400 µm diameter) consists of a conventional transconjunctival sutureless pars plana vitrectomy followed by ILM peeling and endotamponade, mainly with gas or in some cases with silicone oil, resulting in closure rates of over 90% and good functional results. Large (>400 µm diameter), chronic and persistent macular holes remain a surgical challenge since closure rates and functional results decrease with larger macular hole diameters. Various modifications of the conventional surgical technique were introduced to improve anatomic and functional success in refractory cases not suitable for conventional macular hole surgery. These techniques comprise the positioning of tissue at the top of the hole to improve closure as performed by an inner limiting membrane flap and free flap preparation or the transplantation of autologous retinal tissue, lens capsule or amniotic membrane. For the treatment of very large and persistent macular holes, the induction of a localized retinal detachment at the posterior pole by subretinal injection of balanced salt solution and a subsequent attenuation of the rim of the hole during fluid-air exchange has been suggested as a promising surgical technique. In particular, accurate patient education about the expected surgical outcome in this specific group of patients appears important.

Rapid flattening of massive hemorrhagic retinal pigment epithelial detachment secondary to polypoidal choroidal vasculopathy after surgery

PURPOSE

To report 2 polypoidal choroidal vasculopathy (PCV) patients whose massive hemorrhagic pigment epithelial detachments (PEDs) were flattened within a short period after surgery.

OBSERVATIONS

Two PCV patients who presented with submacular hemorrhage and massive hemorrhagic PEDs with sizes of more than 50 disc areas underwent pars plana vitrectomy combined with subretinal injection of tissue plasminogen activator (tPA), intravitreous injection of anti-vascular endothelial growth factor medicine, and perfluoropropane tamponade. The massive hemorrhagic PEDs were flattened within a short period after both surgeries, and both patients experienced improved visual acuity.

CONCLUSIONS

These findings suggest that subretinal injection of tPA together with perfluoropropane tamponade promotes the rapid clearance of hemorrhage under RPE.

iOCT-guided simulated subretinal injections: a comparison between manual and robot-assisted techniques in an ex-vivo porcine model

The purpose of this study is to compare robot-assisted and manual subretinal injections in terms of successful subretinal blistering, reflux incidences and damage of the retinal pigment epithelium (RPE). Subretinal injection was simulated on 84 ex-vivo porcine eyes with half of the interventions being carried out manually and the other half by controlling a custom-built robot in a master-slave fashion. After pars plana vitrectomy (PPV), the retinal target spot was determined under a LUMERA 700 microscope with microscope-integrated intraoperative optical coherence tomography (iOCT) RESCAN 700 (Carl Zeiss Meditec, Germany). For injection, a 1 ml syringe filled with perfluorocarbon liquid (PFCL) was tipped with a 40-gauge metal cannula (Incyto Co., Ltd., South Korea). In one set of trials, the needle was attached to the robot's end joint and maneuvered robotically to the retinal target site. In another set of trials, approaching the retina was performed manually. Intraretinal cannula-tip depth was monitored continuously via iOCT. At sufficient depth, PFCL was injected into the subretinal space. iOCT images and fundus video recordings were used to evaluate the surgical outcome. Robotic injections showed more often successful subretinal blistering (73.7% vs. 61.8%, p > 0.05) and a significantly lower incidence of reflux (23.7% vs. 58.8%, p < 0.01). Although larger tip depths were achieved in successful manual trials, RPE penetration occurred in 10.5% of robotic but in 26.5% of manual cases (p > 0.05). In conclusion, significantly less reflux incidences were achieved with the use of a robot. Furthermore, RPE penetrations occurred less and successful blistering more frequently when performing robotic surgery.

Application of Base Editor-Mediated Genome Editing in Mouse Retina

Base editor is a newly developed genome editing technology that enables conversion of single nucleotides without DNA double-strand breaks (DSB) and maintains a low rate of insertion-deletion (INDEL) errors. With these flexibility and safety, base editor has been widely used in many fields, including inherited retinal disease. The majority of retinal genome editing requires intravitreal and subretinal injection delivery of the therapeutic vector in order to transduce the target cells. Here, we provide an application guide of base editor as performed in the mouse retina.

Ocular Injection Techniques for Retinitis Pigmentosa: Intravitreal, Subretinal, and Suprachoroidal

Ocular gene therapy represents an emerging and promising therapeutic approach for the treatment of several of the inherited retinal diseases. Currently, the focus has been to investigate monogenic inherited retinal disorders. Genetic and cellular therapies can be delivered to the eye by various injection techniques, including those that are intravitreal, subretinal, and suprachoroidal. Each of these three delivery methods are discussed with regard to their historical background, indications, surgical steps, and follow-up.

Robot-assisted subretinal injection system: development and preliminary verification

BACKGROUND

To design and develop a surgical robot capable of assisting subretinal injection.

METHODS

A remote center of motion (RCM) mechanical design and a master-slave teleoperation were used to develop and manufacture the assisted subretinal surgery robot (RASR). Ten fresh isolated porcine eyes were divided into the Robot Manipulation (RM) group and Manual Manipulation (MM) group (5 eyes for each group), and subretinal injections were performed by the robot and manual manipulation methods, respectively. A preliminary verification of the robot was performed by comparing the advantages and disadvantages of the robot manipulation and manual manipulation by using optical coherent tomography (OCT), fundus photography, and video motion capture analysis after the surgery.

RESULTS

Both the robot and the manual manipulation were able to perform subretinal injections with a 100% success rate. The OCT results showed that the average subretinal area was 1.548 mm² and 1.461 mm² in the RM and MM groups, respectively (P > 0.05). Meanwhile the volume of subretinal fluid obtained using the retinal map mode built in OCT was not statistically different between the RM and MM groups (P > 0.05). By analyzing the surgical video using Kinovea, a motion capture and analysis software, the results suggest that the mean tremor amplitude of the RM group was 0.3681 pixels (x direction), which was significantly reduced compared to 18.8779 pixels (x direction) in the MM group (P < 0.0001).

CONCLUSION

Robot-assisted subretinal injection system (RASR) is able to finish subretinal injection surgery with better stability and less fatigue than manual manipulation.

Perifoveal Chorioretinal Atrophy after Subretinal Voretigene Neparvovec-rzyl for RPE65-Mediated Leber Congenital Amaurosis

PURPOSE

To report an anatomic change following subretinal injection of voretigene neparvovec-rzyl (VN) for RPE65-mediated Leber congenital amaurosis.

DESIGN

Multicenter, retrospective chart review.

PARTICIPANTS

Patients who underwent subretinal VN injection at each of 4 participating institutions.

METHODS

Patients were identified as having perifoveal chorioretinal atrophy if (1) the areas of atrophy were not directly related to the touch-down site of the subretinal cannula; and (2) the area of atrophy progressively enlarged over time. Demographic data, visual acuity, refractive error, fundus photographs, OCT, visual fields, and full-field stimulus threshold (FST) were analyzed.

MAIN OUTCOME MEASURES

Outcome measures included change in visual acuity, FST, visual fields, and location of atrophy relative to subretinal bleb position.

RESULTS

A total of 18 eyes of 10 patients who underwent subretinal injection of VN were identified as having developed perifoveal chorioretinal atrophy. Eight of 10 patients (80%) developed bilateral atrophy. The mean age was 11.6 years (range, 5-20 years), and 6 patients (60%) were male. Baseline mean logarithm of the minimum angle of resolution visual acuity and FST were 0.82 (standard deviation [SD], 0.51) and -1.3 log cd.s/m² (SD, 0.44), respectively. The mean spherical equivalent was -5.7 diopters (D) (range, -11.50 to +1.75 D). Atrophy was identifiable at an average of 4.7 months (SD, 4.3) after surgery and progressively enlarged in all cases up to a mean follow-up period of 11.3 months (range, 4-18 months). Atrophy developed within and outside the area of the subretinal bleb in 10 eyes (55.5%), exclusively within the area of the bleb in 7 eyes (38.9%), and exclusively outside the bleb in 1 eye (5.5%). There was no significant change in visual acuity (P = 0.45). There was a consistent improvement in FST with a mean improvement of -3.21 log cd.s/m² (P < 0.0001). Additionally, all 13 eyes with reliable Goldmann visual fields demonstrated improvement, but 3 eyes (23.1%) demonstrated paracentral scotomas related to the atrophy.

CONCLUSIONS

A subset of patients undergoing subretinal VN injection developed progressive perifoveal chorioretinal atrophy after surgery. Further study is necessary to determine what ocular, surgical delivery, and vector-related factors predispose to this complication.

[Macular detachment for treatment of large, persistent and chronic macular holes]

Large, persistent or chronic macular holes still represent a surgical challenge, which can be addressed using the presented surgical technique. A subretinal injection of balanced salt solution (BSS) at the posterior pole of the macular region is performed during transconjunctival pars plana vitrectomy in order to induce an elevation of the neurosensory retina in the macular region. The hole is then attenuated during fluid-air exchange, followed by a gas or silicone oil tamponade. The presented technique appears to be useful for large and persistent macular holes, which are not suitable for conventional macular hole surgery. The exact patient information on the potential outcome of surgery in this specific group of patients seems particularly important.

Release and extraction of retained subfoveal perfluorocarbon liquid facilitated by subretinal BSS, vibration, and gravity: a case report

Background

Perfluorocarbon liquid (PFCL) is an effective surgical adjuvant in performing vitrectomy for severe vitreoretinal pathologies such as proliferative vitreoretinopathy and giant retinal tears. However, subretinal retention of PFCL can occur postoperatively and retained PFCL causes severe visual disorders, particularly when PFCL was retained under the fovea. Although several procedures have been proposed for subfoveal PFCL removal, such as direct aspiration or submacular injection of balanced salt solution (BSS) to dislodge the subfoveal PFCL, the retinal damage associated with these procedures has been a major problem. Here, we report a case of subfoveal retention of PFCL for which we performed a novel surgical technique that attempts to minimize retinal damage.

Case presentation

A 69-year-old man presented with subfoveal retained PFCL after surgery for retinal detachment. To remove the retained PFCL, the internal limiting membrane overlying the subretinal injection site is first peeled to allow low-pressure (8 psi) transretinal BSS infusion, using a 41-gauge cannula, to slowly detach the macula. A small drainage retinotomy is created with the diathermy tip at the inferior position of the macular bleb, sized to be slightly wider than that of the PFCL droplet. The head of the bed is then raised, and the surgeon gently vibrates the patient’s head to release the PFCL droplet to allow it to migrate inferiorly towards the drainage retinotomy. The bed is returned to the horizontal position, and the PFCL, now on the retinal surface, can be aspirated. The subfoveal PFCL is removed while minimizing iatrogenic foveal and macular damage. One month after PFCL removal, the foveal structure showed partial recovery on optical coherence tomography, and BCVA improved to 20/40.

Conclusion

Creating a macular bleb with low infusion pressure and using vibrational forces and gravity to migrate the PFCL towards a retinotomy can be considered as a relatively atraumatic technique to remove subfoveal retained PFCL.

Supplementary information

Supplementary information accompanies this paper at 10.1186/s12886-020-01698-1.

AAV-Mediated Gene Delivery to Foveal Cones

Adeno-associated virus (AAV) has emerged as the vector of choice for delivering genes to the mammalian retina. From the first gene therapy to receive FDA approval for the inherited retinal disease (Luxturna™) to more recent clinical trials using microbial opsins to regain light sensitivity, therapeutic transgenes rely on AAV vectors for safe and efficient gene delivery to retinal cells. Such vectors are administered to the retina via subretinal (SR) injection or intravitreal (IVT) injection routes depending on the targeted retinal cell type. An attractive target for gene therapy is the fovea, bearing the highest concentration of cone cells responsible for our high acuity daylight vision. However, previous clinical trials and large animal studies reported that SR administration of vector under the cone-exclusive fovea disrupts its fine structure and might impair visual acuity. Due to its technical difficulty and potential risks, alternatives to vector injection under this delicate region have been investigated by using novel AAV capsid variants identified via rational design or directed evolution. We recently established new vector-promoter combinations to overcome the limitations associated with AAV-mediated cone transduction in the fovea. Our methods provide efficient foveal cone transduction without detaching this delicate region and rely on the use of engineered AAVs and optimal promoters compatible with optogenetic vision restoration. Here we describe in detail our AAV vectors, methods for intravitreal and subretinal injections as well as pre- and postoperative procedures as performed in cynomolgus macaques.

Subretinal injection of ranibizumab in advanced pediatric vasoproliferative disorders with total retinal detachments

PURPOSE

To describe the surgical procedures, outcomes, and complications of a novel technique of subretinal injection of ranibizumab (SRR).

METHODS

Between September 2012 and September 2018, 37 eyes of 26 consecutive children with vascularly active total retinal detachments in 1 or both eyes treated with SRR as primary treatment were included in this retrospective study. All included eyes received subretinal injection of ranibizumab (0.25 mg/ 0.025 ml). Data included demographics, ocular examination, and anatomic outcomes, following treatment and complications of eyes after SRR were collected.

RESULTS

Eleven patients had bilateral SRR injections and 15 had monocular SRR injection. Thirteen patients were diagnosed as retinopathy of prematurity. Of all patients, the mean gestational age was 34.5 ± 5.1 weeks (range: 29.6~40.7 weeks), and birth weight was 2328.1 ± 1083.9 g (range: 940~3900 g). On 1-week postoperative follow-up, vascular activity decreased in all 37 eyes (100%). On the 1-month postoperative follow-up, vascular activity decreased but remained in 24 eyes (24/35, 68.6%) of 16 patients and vanished in 11 eyes (11/35, 31.4%) of 9 patients. No eye needed a secondary anti-VEGF therapy. Local subconjunctival hemorrhage was noted in two eyes (2/37, 5.4%). Localized wound leakage of subretinal fluid was also noted in one eye (1/37, 2.7%).

CONCLUSIONS

In this very limited study, we showed that SRR in vascularly active advanced pediatric vasoproliferative disorders with total retinal detachments is effective and promising, although more extensive controlled trials will be needed to confirm its safety and efficacy.

Advancing Gene Therapy for PDE6A Retinitis Pigmentosa

Mutations in the gene encoding the phosphodiesterase 6 alpha subunit (PDE6A) account for 3-4% of autosomal recessive retinitis pigmentosa (RP), and currently no treatment is available. There are four animal models for PDE6A-RP: a dog with a frameshift truncating mutation (p.Asn616ThrfsTer39) and three mouse models with missense mutations (Val685Met, Asp562Trp, and Asp670Gly) showing a range of phenotype severities. Initial proof-of-concept gene augmentation studies in the Asp670Gly mouse model and dog model used a subretinally delivered adeno-associated virus serotype 8 with a 733 tyrosine capsid mutation delivering species-specific Pde6a cDNAs. These restored some rod-mediated function and preserved retinal structure. Subsequently, a translatable vector (AAV8 with a human rhodopsin promoter and human PDE6A cDNA) was tested in the dog and the Asp670Gly mouse model. In the dog, there was restoration of rod function, a robust rod-mediated ERG, and introduction of dim-light vision. Treatment improved morphology of the photoreceptor layer, and the retina was preserved in the treated region. In the Asp670Gly mouse, therapy also preserved photoreceptors with cone survival being reflected by maintenance of cone-mediated ERG responses. These studies are an important step toward a translatable therapy for PDE6A-RP.

[Surgery of large and persistent macular holes]

Modern macular hole surgery results in high closure rates of over 90% and good functional results especially in macular holes up to 400 µm in diameter. The standard of care in most of these cases consists of transconjunctival sutureless pars plana vitrectomy, peeling of the inner limiting membrane (ILM) around the hole, followed by gas tamponade and positioning of the patient. As closure rates and functional results decrease with larger macular hole diameters over approximately 400 µm, alternative surgical techniques have been introduced to improve anatomical and functional results in these cases. These techniques include the positioning of tissue within the macular hole to improve hole closure. This can be performed using an ILM flap or free flap technique and the transplantation of autologous retinal tissue, lens capsule or homologous amniotic tissue in or under the defect. An alternative promising approach is the attenuation of the rim of the hole by induction of a localized retinal detachment at the posterior pole which is achieved by subretinal injection of balanced salt solution (BSS) using a 41 gauge needle. The operation is completed by an endotamponade using gas or silicone oil.

Real-time OCT guidance and multimodal imaging monitoring of subretinal injection induced choroidal neovascularization in rabbit eyes

Choroidal neovascularization (CNV) is a major cause of vision loss that consists of abnormal growth of new blood vessels from the choroidal vasculature. High resolution in vivo imaging of animal models is essential to better elucidate and conduct research on CNV. This study evaluates a novel multimodal imaging platform combining optical coherence tomography (OCT) and photoacoustic microscopy (PAM). Using real-time OCT guidance subretinal injection to induce and multimodality imaging system to monitor CNV over time in rabbit eyes. The significance of our work lies in providing the optimal setting and conditions to make use of the OCT image guided system to improve the consistency and reproducibility of experimental results in subretinal injection induced CNV model in rabbits. For the first time, this study successfully demonstrated the dual-modality PAM-OCT system, without using exogenous contrast agents, can detect and visualize CNV in the rabbit eye with high resolution. This is promising system for diagnosing and monitoring CNV.

Subretinal transplantation of human embryonic stem cell-derived retinal pigment epithelium (MA09-hRPE): A safety and tolerability evaluation in minipigs

This study aimed to determine the safety and tolerability of the subretinal injection of hESC-derived RPE cells at higher doses than the established clinical dose (5 × 10⁴ cells/150 μL) by using minipigs. The hESC-derived RPE cells (60 or 120 × 10⁴ cells/150 μL) were injected in subretinal region, and minipigs were sacrificed at Weeks 4, 8, and 12 post-surgery. Time-course examination was performed by using fundus photography, optical coherence tomography (OCT), histopathology, and fluorescence in situ hybridization (FISH). After surgery, retinal bleb and pigmentation were seen and retinal bleb became smaller gradually. In histopathology, cell clusters consisting of a uniform population of the round to oval cells were seen at the subretinal injection site. In immunohistochemistry, most of the cells were positive for anti-CD3 and CD45 antibodies but negative for anti-human nuclei antibody; transplanted cells were not detectable by DNA probe in FISH assay. Cell clusters were thought to be a host immune response to trauma or transplanted cells. There were no other changes related to subretinal RPE cell injection. These results suggested that subretinal injection of hESC-derived RPE cells (60 and 120 × 10⁴ cells/150 μL) in minipigs is well-tolerated and safe.

In Vivo Expression of Mutant Calpains in the Eye Using Lentivirus

Exome sequencing has identified many candidate genes and mutations for human diseases, but the functional validation of these candidates is a time-consuming and costly process. Here, we describe a method which uses lentiviruses to overexpress calpain mutations that may play a role in dominant diseases such as autosomal dominant neovascular inflammatory vitreoretinopathy (ADNIV). The use of lentivirus to deliver the mutant calpain allows for a cost-effective, rapid, and efficient approach to test whether or not a candidate gene mutation from exome sequencing acts as the disease-causing allele for a human disorder. This method also provides for a comparison of different candidate mutations from a single gene identified by exome sequencing, as well as elucidating the mechanisms underlying these complex human disorders. Furthermore, this chapter focuses on two different methods to deliver mutant calpain to the cells of the eye, using either a subretinal or an intravitreal injection of the lentivirus into the mouse eye.

Optimized Subretinal Injection Technique for Gene Therapy Approaches

Gene therapy for inherited eye diseases requires local viral vector delivery by intraocular injection. Since large animal models are lacking for most of these diseases, genetically modified mouse models are commonly used in preclinical proof-of-concept studies. However, because of the relatively small mouse eye, adverse effects of the subretinal delivery procedure itself may interfere with the therapeutic outcome. The method described here aims to provide the details relevant to perform a transscleral pars plana virus-mediated gene transfer to achieve an optimized therapeutic effect in the small mouse eye.

In Vivo Electroporation of Developing Mouse Retina

In vivo electroporation enables the transformation of retinal tissue with engineered DNA plasmids, facilitating the selective expression of desired gene products. This method achieves plasmid transfer via the application of an external electrical field, which both generates a transient increase in the permeability of cell plasma membranes, and promotes the incorporation of DNA plasmids by electrophoretic transfer through the permeabilized membranes. Here we describe a method for the preparation, injection, and electroporation of DNA plasmids into neonatal mouse retinal tissue. This method can be utilized to perform gain of function or loss of function studies in the mouse. Experimental design is limited only by construct availability.

AAV Gene Augmentation Therapy for CRB1-Associated Retinitis Pigmentosa

Mutations in the CRB1 gene account for around 10,000 persons with Leber congenital amaurosis (LCA) and 70,000 persons with retinitis pigmentosa (RP) worldwide. Therefore, the CRB1 gene is a key target in the fight against blindness. A proof-of-concept for an adeno-associated virus (AAV)-mediated CRB2 gene augmentation therapy for CRB1-RP was recently described. Preclinical studies using animal models such as knockout or mutant mice are crucial to obtain such proof-of-concept. In this chapter we describe a technique to deliver AAV vectors, into the murine retinas, via the subretinal route. We also present protocols to detect expression of the therapeutic protein by fluorescence immunohistochemistry and to perform histological studies using ultra-thin sections stained with toluidine blue. These techniques in combination with electroretinography and visual behavior tests are in principle sufficient to obtain proof-of-concept for new gene therapies.

Subretinal Injection: A Review on the Novel Route of Therapeutic Delivery for Vitreoretinal Diseases

Compared to intravitreal injection, subretinal injection has more direct effects on the targeting cells in the subretinal space, which provides a new therapeutic method for vitreoretinal diseases, especially when gene therapy and/or cell therapy is involved. To date, subretinal delivery has been widely applied by scientists and clinicians as a more precise and efficient route of ocular drug delivery for gene therapies and cell therapies including stem cells in many degenerative vitreoretinal diseases, such as retinitis pigmentosa, age-related macular degeneration, and Leber's congenital amaurosis. However, clinicians should be aware of adverse events and possible complications when performing subretinal delivery. In the present review, the subretinal injection used in vitreoretinal diseases for basic research and clinical trials is summarized and described. Different methods of subretinal delivery, as well as its benefits and challenges, are also briefly introduced.

Distinct Expression Patterns of AAV8 Vectors with Broadly Active Promoters from Subretinal Injections of Neonatal Mouse Eyes at Two Different Ages

The retinal expression patterns were analyzed following the injection of serotype 8 adeno-associated virus (AAV8) vectors that utilize two broadly active and commonly used sets of transcription regulatory sequences. These include the human cytomegalovirus (CMV) immediate early (IE) enhancer/promoter and the hybrid CAG element (also known as CAGGS or CBA) composed of a partial human CMV IE enhancer and the chicken β-actin promoter and intron. Subretinal delivery to postnatal day 0 (P0) or 6 (P6) mouse eyes resulted in efficient labeling of retinal cells, but with very distinct patterns. With P0 delivery, AAV8-CMV-GFP selectively labelled photoreceptors, while AAV8-CAG-GFP efficiently labeled both outer and inner retinal neurons, including photoreceptors, horizontal cells, amacrine cells and retinal ganglion cells. With P6 delivery, both vectors led to efficient labeling of photoreceptors and Müller glia cells, but not of inner retinal neurons. Our results suggest that the cell types that express the genes encoded by subretinally delivered AAV8 vectors are determined by both the timing of the injection and the regulatory sequences.

Subretinal AAV2.COMP-Ang1 suppresses choroidal neovascularization and vascular endothelial growth factor in a murine model of age-related macular degeneration

To assess whether Tie2-mediated vascular stabilization ameliorates neovascular age-related macular degeneration (AMD), we investigated the impact of adeno-associated virus-mediated gene therapy with cartilage oligomeric matrix protein angiopoietin-1 (AAV2.COMP-Ang1) on choroidal neovascularization (CNV), vascular endothelial growth factor (VEGF), and hypoxia-inducible factor (HIF) in a mouse model of the disease. We treated mice with subretinal injections of AAV2.COMP-Ang1 or control (AAV2.AcGFP, AAV2.LacZ, and phosphate-buffered saline). Subretinal AAV2 localization and plasmid protein expression was verified in the retinal pigment epithelium (RPE)/choroid of mice treated with all AAV2 constructs. Laser-assisted simulation of neovascular AMD was performed and followed by quantification of HIF, VEGF, and CNV in each experimental group. We found that AAV2.COMP-Ang1 was associated with a significant reduction in VEGF levels (29-33%, p < 0.01) and CNV volume (60-70%, p < 0.01), without a concomitant decrease in HIF1-α, compared to all controls. We concluded that a) AAV2 is a viable vector for delivering COMP-Ang1 to subretinal tissues, b) subretinal COMP-Ang1 holds promise as a prospective treatment for neovascular AMD, and c) although VEGF suppression in the RPE/choroid may be one mechanism by which AAV2.COMP-Ang1 reduces CNV, this therapeutic effect may be hypoxia-independent. Taken together, these findings suggest that AAV2.COMP-Ang1 has potential to serve as an alternative or complementary option to anti-VEGF agents for the long-term amelioration of neovascular AMD.

Subretinal injection of recombinant tissue plasminogen activator for submacular hemorrhage associated with ruptured retinal arterial macroaneurysm

PURPOSE

To evaluate the surgical outcomes of small-gauge vitrectomy with subretinal injection of recombinant tissue plasminogen activator (rt-PA) for a submacular hemorrhage caused by a ruptured retinal arterial macroaneurysm (RAM).

METHODS

Non-comparative, consecutive case-series performed at two ophthalmological institutions. We examined 22 eyes of 22 patients with a submacular hemorrhage associated with a RAM but without a preretinal or sub-internal limiting membrane hemorrhage at the fovea. During 25-gauge vitrectomy, approximately 4000-8000 IU of rt-PA was injected subretinally, followed by the injection of air or 10 % sulfur hexafluoride as a tamponade. The patients maintained an upright position for 1 hour, then turned to a facedown position for 1 to 3 days. The best-corrected visual acuity (BCVA) and postoperative complications were evaluated.

RESULTS

The average interval from the onset of symptoms to surgery was 8.4 ± 7.6 days, and the average size of the subretinal hemorrhage was 3.4 ± 1.0 disc diameters. The submacular hemorrhage was displaced from the foveal area in all eyes after 1 week. The mean baseline BCVA was 1.41 ± 0.41 logMAR units, and it improved to 0.91 ± 0.43 at 1 month and to 0.64 ± 0.45 at the final visit (P = 0.0001, P < 0.0001 respectively). A macular hole was detected intraoperatively in two eyes and postoperatively in two eyes, and both were closed by internal limiting membrane peeling or a second vitrectomy.

CONCLUSIONS

Small-gauge vitrectomy with subretinal rt-PA injection and gas tamponade were effective in displacing a submacular hemorrhage associated with a RAM.