Advantages of robotic assistance over a manual approach in simulated subretinal injections and its relevance for gene therapy

Subretinal injection is a method for gene delivery to treat genetic diseases of the photoreceptors and retinal pigment epithelium. A reflux-free subretinal injection is important to allow effective, safe, and cost-effective gene therapy to the retina. We report on a comparison between manual and robotic assistance in simulated subretinal injections using an artificial retina model. Nine surgeons carried out the procedure with and without the Preceyes Surgical System, using an OPMI Lumera 700 Zeiss surgical microscope equipped with intra-operative optical coherence tomography. Success in creating a bleb without reflux, injection duration, drift, tremor, and increase in the diameter of the puncture hole were analyzed. Robotic assistance improved drift (median 16 vs 212 µm), tremor (median 1 vs 18 µm), enlargement of the retinal hole, and allowed for prolonged injection times (median 52 vs 29 sec). Robotic assistance allowed higher rate of bleb formation (8/9 vs 4/9 attempts) with a moderate reduction in reflux (7/9 vs 8/9 attempts) in this artificial model. Robotic assistance can significantly contribute to subretinal injections and provide quantifiable parameters in assessing surgical and clinical success of novel retinal gene therapies.

Iatrogenic Retinal Penetration from Intravitreal Injections

We present 2 cases of iatrogenic retinal penetration from intravitreal (IVT) injections in a retrospective noncomparative case series of 2 patients. The first patient, an 81-year-old Caucasian male, developed dense vitreous hemorrhage soon after receiving an IVT bevacizumab injection for macular edema from central retinal vein occlusion. A 25-g vitrectomy 1 week later showed a retinal hole surrounded by fresh hemorrhages in the same quadrant as the IVT injection. The second patient, an 87-years-old male, developed a retinal detachment after 28 injections of anti-VEGF medications for neovascular AMD. A peripheral round hole was observed during vitrectomy without any lattice degeneration in the same quadrant as prior IVT injections. Both eyes were pseudophakic, had normal axial lengths, and received injections without measuring the injection site. Retinal penetration from IVT injections can result in serious sight-threatening complications. Measuring the injection site from the limbus should be part of safe IVT injection technique.

Ab-interno surgical technique for the implantation of a wireless subretinal prosthesis in mini-pigs

We sought to describe the surgical techniques required in the ab-interno method to implant subretinal prostheses in mini-pigs and suggest tips to facilitate optimal outcomes. During vitrectomy, the use of valved trocar cannulas was essential to stabilize the detached retina and implanted chip. As a first step in retinal detachment, a 23-gauge cannula with very small amount of viscoelastic material was used to establish the retinal hole and promote retinal detachment. Then, balanced salt solution was applied to increase the retinal detachment and diathermy was used to make opening for subretinal prosthesis. For easy positioning of the subretinal prosthesis, a curved laser probe was adopted when handling the subretinal prosthesis under the retina. After surgery, the sclerotomy sites were tightly sutured to prevent silicone oil leakage. Without special equipment, such as a 41-gauge tip, retinal detachment could be induced easily, while the prosthesis was also successfully inserted and manipulated under the retina without an iatrogenic retinal tear. Two weeks after the operation, the oil fully occupied the intraocular volume without leakage. The subretinal prosthesis remained stable without complication. Understanding the principle of the ab-interno method and considering several tips for improving surgical access may help to enhance surgical success rates of subretinal prostheses implantation.

Human amniotic membrane patch and platelet-rich plasma to promote retinal hole repair in a recurrent retinal detachment

Purpose: To present a modified surgical technique, based on a combination of human amniotic membrane (hAM) patch and autologous Platelet-rich plasma (PRP) in a case of recurrent retinal detachment (RRD) due to a perivascular retinal hole over an area of staphyloma in an eye with pathologic myopia. Methods: Presenting the surgical technique with the disposal of surgical video. After performing 23-gauge pars plana vitrectomy (PPV) the hAM patch was inserted under the neuroretina through the perivascular hole and PRP was injected on top to speed up the closure of the hole. To complete the surgical procedure High Viscosity Silicon oil (5000cst) was used as tamponade. The patient was prescribed to maintain a face-down position for the first 3 days after the operation. Follow-up was evaluated through Optical coherence tomography (OCT) scans. Results: The 3 days postoperative OCT showed a flat retina with the filling of the myopic staphyloma. The hAM patch was well positioned and the retinal hole could not be identified. At 6 weeks from intervention, the site of the retinal hole at OCT scan was covered by new tissue. Silicone oil was removed 3 months later with no recurrence. Conclusion: hAM transplantation is a novel technique in case of retinal detachment recurrences to seal retinal holes over high myopic chorioretinal atrophy. The adjunctive use of PRP and high viscosity silicon oil allows to reducing the standard face-down positioning timing, representing a valid solution for elderly patients who have difficulties maintaining the position for long periods.

Scleral buckling—a brief historical overview and current indications

The key to successful management of rhegmatogenous retinal detachment (RRD) is to find and seal all of the retinal breaks, and the two main surgical techniques used to achieve this are scleral bucking (SB) or pars plana vitrectomy (PPV). Techniques for SB have remained mostly unchanged for the last 60 years, whilst PPV techniques and instruments have developed substantially over that time and have greatly contributed to increased success rate for types and configurations of retinal detachments unsuitable or difficult to manage with buckling alone. However, there is a growing dependency to rely on PPV as the sole and only approach for repair of all types of retinal detachment, such that some centres are no longer offering training in scleral buckling. There are also many studies comparing SB with PPV, but many of these lack information on the type, technique or rationale for deployment of the buckle. Many studies deploy the same scleral buckle technique without customising it to the type, position or number of tears being treated. Scleral buckling is not a one-size-fits-all technique. It requires careful patient selection and careful buckle selection and orientation tailored to the tear(s) to ensure success. When used appropriately, it is a simple and highly effective technique, particularly for retinal dialyses, round retinal hole detachments and selected cases of retinal detachment associated with horseshoe retinal tears. There is no doubt that for some more complex cases, such as multiple large breaks, giant retinal tears, bullous detachments and cases complicated by proliferative retinopathy, PPV offers a safer and more effective management. However, SB remains an important and relevant surgical technique, and for the right cases, the results can be superior to PPV with reduced comorbidity.

Solar maculopathy: prognosis over one year follow up

Background To document the visual acuity, spectral domain optical coherence tomography (SD-OCT) findings and prognosis in10 eyes of 6 patients with foveal damage from solar retinopathy in 1 year. Methods This was a prospective, observational case series of patients presented by solar maculopathy at Ophthalmology department, Sohag University. All patients underwent visual acuity (VA) testing, refraction, dilated fundus examination fluorescein angiography (FA) and SD-OCT (spectral Domain ocular coherence Tomography) imaging and follow up for 1 year. Results The mean age was 16.5 years (range 9–27 years, both eyes are affected in 4 patients. The mean spherical equivalent (SE) was – 0.25 ± 0.50 D. The visual acuity of the affected eyes ranged from 0.4 to 0.9 on presentation. At presentation Significant foveal pathology was identified on SD-OCT in 10 eyes, All eyes showed disruption of the photoreceptor ellipsoid zone and the interdigitation zone on SD-OCT, Follow up of the cases continued for 1 year.100% of cases showed improvement in VA: 20% eyes regained 1, 50% eyes with VA of 0.9; two eyes 20% 0.8 and one eyes (10%) with 0.4. The improvement began after 1 week and reached its maximum and became stationary after the 6th month of follow up, the outer retinal hole persist in OCT in 80% of cases. Conclusion Solar maculopathy has a good prognosis yet shows no improvement after 6 months. Young age might pose as a risk factor.