Spontaneous Retinal Reattachment Research Articles

Kamuvudine-9 Protects Retinal Structure and Function in a Novel Model of Experimental Rhegmatogenous Retinal Detachment.

Rhegmatogenous retinal detachment (RRD) is a vision-threatening event that benefits from surgical intervention. While awaiting surgical reattachment, irreversible hypoxic and inflammatory damage to the retina often occurs. An interim therapy protecting photoreceptors could improve functional outcomes. We sought to determine whether Kamuvudine-9 (K-9), a derivative of nucleoside reverse transcriptase inhibitors (NRTIs) that inhibits inflammasome activation, and the NRTIs lamivudine (3TC) and azidothymidine (AZT) could protect the retina following RRD. RRD was induced in mice via subretinal injection (SRI) of 1% carboxymethylcellulose (CMC). To simulate outcomes following the clinical management of RRD, we determined the optimal conditions by which SRI of CMC induced spontaneous retinal reattachment (SRR) occurs over 10 days (RRD/SRR). K-9, 3TC, or AZT was administered via intraperitoneal injection. Inflammasome activation pathways were monitored by abundance of cleaved caspase-1, IL-18, and cleaved caspase-8, and photoreceptor death was assessed by TUNEL staining. Retinal function was assessed by full-field scotopic electroretinography. RRD induced retinal inflammasome activation and photoreceptor death in mice. Systemic administration of K-9, 3TC, or AZT inhibited retinal inflammasome activation and photoreceptor death. In the RRD/SRR model, K-9 protected retinal electrical function during the time of RRD and induced an improvement following retinal reattachment. K-9 and NRTIs exhibit anti-inflammatory and neuroprotective activities in experimental RRD. Given its capacity to protect photoreceptor function during the period of RRD and enhance retinal function following reattachment, K-9 shows promise as a retinal neuroprotectant and warrants study in RRD. Further, this novel RRD/SRR model may facilitate experimental evaluation of functional outcomes relevant to RRD.

Optimizing Donor Cellular Dissociation and Subretinal Injection Parameters for Stem Cell-Based Treatments.

Subretinal delivery of stem cell‐derived retinal cells as a strategy to treat retinal degenerative blindness holds great promise. Currently, two clinical trials are underway in which human fetal retinal progenitor cells (RPCs) are being delivered to patients by intravitreal or subretinal injection to preserve or restore vision, respectively. With the advent of the induced pluripotent stem cell (iPSC), and in turn three‐dimensional derivation of retinal tissue, it is now possible to generate autologous RPCs for cell replacement. The purpose of this study was to evaluate the effect of commonly used cell isolation and surgical manipulation strategies on donor cell viability. iPSC‐RPCs were subjected to various conditions, including different dissociation and isolation methods, injection cannula sizes, and preinjection storage temperatures and times. The effects of commonly used surgical techniques on both host and donor cell viability were evaluated in Yucatan mini‐pigs (n = 61 eyes). We found a significant increase in cell viability when papain was used for RPC isolation. In addition, a significant decrease in cell viability was detected when using the 41G cannula compared with 31G and at storage times of 4 hours compared with 30 minutes. Although 96.4% of all eyes demonstrated spontaneous retinal reattachment following injection, retinal pigment epithelium (RPE) abnormalities were seen more frequently in eyes receiving injections via a 31G cannula; interestingly, eyes that received cell suspensions were relatively protected against such RPE changes. These findings indicate that optimization of donor cell isolation and delivery parameters should be considered when developing a subretinal cell replacement strategy. stem cells translational medicine 2019;8:797&809

ANTIANGIOGENIC THERAPY WITH INTRAVITREAL BEVACIZUMAB FOR RETINOPATHY OF PREMATURITY

To evaluate the role of antiangiogenic therapy with intravitreal bevacizumab for retinopathy of prematurity (ROP). In this noncomparative, prospective, interventional case series, bevacizumab was injected into the vitreous of patients with ROP in three different groups: group I, patients with stage IVa or IVb ROP who had no response to conventional treatment; group II, patients with threshold ROP who were difficult to treat with conventional therapy because of poor visualization of the retina; and group III, patients with high-risk prethreshold or threshold ROP. Thirteen patients (18 eyes; mean age +/- SD, 4 +/- 3 months; mean follow-up, 6 months) were included in the study. We found neovascular regression in 17 eyes. One patient with stage IVa ROP had spontaneous retinal reattachment after an intravitreal injection of bevacizumab. There were no serious ocular or systemic adverse events. The use of bevacizumab may be promising in the treatment of patients with ROP. Further studies need to be performed to determine the safety and long-term efficacy of intravitreal injection of bevacizumab, either as first-line therapy or after failure of conventional therapy.

Posterior vitreous findings in cases of spontaneous retinal reattachment

Purpose To describe the posterior vitreous findings in two patients with retinal detachment who experienced spontaneous retinal reattachment. Design Two observational case reports. Testing Biomicroscopic and high-resolution echographic evaluation of the vitreoretinal relationships. Main outcome measures Retinal reattachment and echographic vitreoretinal relationships. Results Two patients, one with a rhegmatogenous retinal detachment and one with a tractional retinal detachment, were noted to have a partial posterior vitreous detachment with vitreoretinal adherence at the time of presentation. Spontaneous retinal reattachment occurred in both cases, with echography showing complete vitreous separation from the retina. Conclusions Complete posterior vitreous detachment may release tractional components in retinal detachment and contribute to spontaneous retinal reattachment.

Diplopia after limited macular translocation surgery

Purpose: Full macular translocation surgery relocates the fovea away from choroidal neovascularization, inducing significant postoperative torsional diplopia. In “limited macular translocation,” a saline-induced retinal detachment is followed by scleral imbrication with mattress sutures and spontaneous retinal reattachment. In this study, diplopia was characterized in patients treated with limited macular translocation. Methods: Two surgeons performed retinal translocation surgery on 250 patients over an 18-month time span. The extent and direction of the retinal translocation, and the amount and location of scleral imbrication, were recorded. All patients complaining of diplopia were referred for ocular motility evaluation and treatment. Results: Thirteen (5.2%) patients complained of occasional or constant diplopia. Imbricating sutures were placed supero-temporally in all cases. Inferior foveal translocation ranged from 200 to 2115 μm (median, 1750 μm). Visual acuity ranged from 20/40 to 20/400 in the operated eye. Prism-and-cover testing underestimated the strabismus when compared with subjective testing. In 3 patients, there was no shift on alternate-cover testing despite binocular diplopia. Excyclotorsion ranged from 0° to 16°. Diplopia resolved in 10 cases with prism; 3 required an occlusive filter for distortion or aniseikonia. One patient underwent successful strabismus surgery to eliminate dependence on prism glasses. Conclusions: Limited macular translocation only rarely produces symptomatic diplopia. Suprisingly, traditional prism-and-cover testing does not reliably quantify the misalignment. This may result from the combination of a persistent macular scotoma and a repositioned fovea relative to the peripheral retina. Prism therapy is generally satisfactory in the absence of retinal distortion or aniseikonia. (J AAPOS 2001;5:388-94)

Therapeutic ultrasound in the treatment of retinal detachment: clinical observations and light and electron microscopy.

Osmotically-induced retinal detachments were created in rabbit eyes and treated with therapeutic ultrasound. Control eyes showed spontaneous retinal reattachment after ten days (range, 8-10 days), while eyes treated with therapeutic ultrasound showed retinal reattachment in a shorter time (average, 4.5 days). Light and electron microscopy demonstrates at least three major differences in the ultrasound-treated eyes compared to the controls. These findings are evidence of an earlier retinal reattachment, a stronger chorioretinal adhesion, less damage and faster repair in the ultrasound-treated retina than in the control retina. This method of producing chorioretinal adhesions may have applications in certain types of retinal detachments where choroidal thickness or vitreous opacity preclude conventional cryopexy, diathermy or photocoagulation techniques.

Spontaneous Reattachment of the Retina Despite Proliferative Vitreoretinopathy

In six cases of spontaneous retinal reattachment despite severe proliferative vitreoretinopathy, the retina was initially attached after a buckling procedure or vitreous surgery for proliferative vitreoretinopathy. However, each retina suddenly detached several weeks later. Surprisingly, the retinas settled slowly during the following weeks without further treatment. One case was marked by repeated episodes of detachment and reattachment. In none of the cases could an open retinal break be detected. In certain cases of proliferative vitreoretinopathy in which no open break is apparent and the detachment appears to be tractional, an observation period of several weeks may allow the retina to reattach spontaneously without further surgery.

BILATERAL UVEITIS, POLIOSIS AND RETINAL DETACHMENT WITH RECOVERY

Harada,1in 1926, first described bilateral detachment of the retina in the course of low grade uveitis as an independent disease. The typical onset of an acute diffuse exudative choroiditis or uveitis accompanied by poliosis, and sometimes alopecia and deafness, with a relatively favorable prognosis for spontaneous retinal reattachment, warrants consideration of this disease as an entity. It is invariably bilateral. The onset is acute, is accompanied by headache and occasional vomiting or nausea and is characterized by low grade inflammatory symptoms in the anterior segment of the uvea. In the early stage opacities of the vitreous and edema of the disk suggestive of papillitis are present ; these are followed by an extensive detachment. The detachment has a definite tendency to disappear within a few weeks, and the healing results in good visual acuity. The fundi show much depigmentation, and in the periphery white patches suggestive of sympathetic choroiditis