PRIMA subretinal wireless photovoltaic microchip implantation in non-human primate and feline models

Purpose To evaluate the surgical technique for subretinal implantation of two sizes of PRIMA photovoltaic wireless microchip in two animal models, and refine these surgical procedures for human trials. Methods Cats and Macaca fascicularis primates with healthy retina underwent vitrectomy surgery and were implanted with subretinal wireless photovoltaic microchip at the macula/central retina. The 1.5mm PRIMA chip was initially studied in feline eyes. PRIMA implant (2mm,1.5mm sizes) arrays were studied in primates. Feasibility of subretinal chip implantation was evaluated with a newly-developed surgical technique, with surgical complications and adverse events recorded. Results The 1.5mm implant was placed in the central retina of 11 feline eyes, with implantation duration 43-106 days. The 1.5mm implant was correctly positioned into central macula of 11 primate eyes, with follow-up periods of minimum 6 weeks (n = 11), 2 years (n = 2), and one eye for 3 years. One primate eye underwent multi-chip 1.5mm implantation using two 1.5mm chips. The 2mm implant was delivered to 4 primate eyes. Optical coherence tomography confirmed correct surgical placement of photovoltaic arrays in the subretinal space in all 26 eyes. Intraoperative complications in primate eyes included retinal tear, macular hole, retinal detachment, and vitreous hemorrhage that resolved spontaneously. Postoperatively, there was no case of significant ocular inflammation in the 1.5mm implant group. Conclusions We report subretinal implantation of 1.5mm and 2mm photovoltaic arrays in the central retina of feline and central macula of primate eyes with a low rate of device-related complications. The in vivo PRIMA implantation technique has been developed and refined for use for a 2mm PRIMA implant in ongoing human trials

Early vitrectomy for exogenous endophthalmitis following surgery

BACKGROUND: Endophthalmitis is a sight-threatening emergency that requires prompt diagnosis and treatment. The condition is characterised by purulent inflammation of the intraocular fluids caused by an infective agent. In exogenous endophthalmitis, the infective agent is foreign and typically introduced into the eye through intraocular surgery or open globe trauma. OBJECTIVES: To assess the potential role of combined pars plana vitrectomy and intravitreal antibiotics in the acute management of exogenous endophthalmitis, versus the standard of care, defined as vitreous tap and intravitreal antibiotics. SEARCH METHODS: We searched the Cochrane Central Register of Controlled Trials (CENTRAL; which contains the Cochrane Eyes and Vision Trials Register; 2022, Issue 5); Ovid MEDLINE; Ovid Embase; the International Standard Randomised Controlled Trial Number registry; ClinicalTrials.gov, and the World Health Organization International Clinical Trials Registry Platform. There were no restrictions to language or year of publication. The date of the search was 5 May 2022. SELECTION CRITERIA: We included randomised controlled trials (RCTs) that compared pars plana vitrectomy and intravitreal injection of antibiotics versus intravitreal injection of antibiotics alone, for the immediate management of exogenous endophthalmitis. DATA COLLECTION AND ANALYSIS: We used standard methods expected by Cochrane. Two review authors independently screened search results and extracted data. We considered the following outcomes: visual acuity improvement and change in visual acuity at three and six months; additional surgical procedures, including vitrectomy and cataract surgery, at any time during follow-up; quality of life and adverse effects. We assessed the certainty of the evidence using the GRADE approach.  MAIN RESULTS: We identified a single RCT that met our inclusion criteria. The included RCT enrolled a total of 420 participants with clinical evidence of endophthalmitis, within six weeks of cataract surgery or secondary intraocular lens implantation. Participants were randomly assigned according to a 2 x 2 factorial design to either treatment with vitrectomy (VIT) or vitreous tap biopsy (TAP) and to treatment with or without systemic antibiotics. Twenty-four participants did not have a final follow-up: 12 died, five withdrew consent to be followed up, and seven were not willing to return for the visit.  The study did not report visual acuity according to the review's predefined outcomes. At three months, 41% of all participants achieved 20/40 or better visual acuity and 69% had 20/100 or better acuity. The study authors reported that there was no statistically significant difference in visual acuity between treatment groups (very low-certainty evidence). There was low-certainty evidence of a similar requirement for additional surgical procedures (risk ratio RR 0.90, 95% confidence interval 0.66 to 1.21). Adverse effects included: VIT group: dislocated intraocular lens (n = 2), macular infarction (n = 1). TAP group: expulsive haemorrhage (n = 1). Quality of life and mean change in visual acuity were not reported.  AUTHORS' CONCLUSIONS: We identified a single RCT (published 27 years ago) for the role of early vitrectomy in exogenous endophthalmitis, which suggests that there may be no difference between groups (VIT vs TAP) for visual acuity at three or nine months' follow-up.   We are of the opinion that there is a clear need for more randomised studies comparing the role of primary vitrectomy in exogenous endophthalmitis. Moreover, since the original RCT study, there have been incremental changes in the surgical techniques with which vitrectomy is performed. Such advances are likely to influence the outcome of early vitrectomy in exogenous endophthalmitis

Intravitreal ocriplasmin for the treatment of vitreomacular traction and macular hole- A study of efficacy and safety based on NICE guidance.

To evaluate the real world clinical outcomes of intravitreal ocriplasmin in patients with vitreomacular traction (VMT) with and without full thickness macular holes (FTMH) treated according to NICE guidance.Retrospective observational case series of 25 patients treated with a single intravitreal ocriplasmin injection between December 2013 and December 2015. Best corrected visual acuity and optical coherence tomography exams were performed to determine visual outcomes and anatomical VMT release and FTMH closure over time. Two patient groups were identified: ocular macular co-morbidity (OCM) and no OCM (nOCM), with follow-up at 4, 12, and 24 weeks.Twenty-five patients were identified that included 19 patients with VMT, and 6 patients with VMT plus FTMH. In the nOCM group of 22 patients, the release rate of VMT was 44%, 63%, and 69% at 4, 12 and 24 weeks respectively. In the "real-world" OCM group of 25 patients, the VMT release rate was 37%, 53%, and 58% at the same time-points. In both groups, the FTMH closure rate was 33%, 50%, and 67% at 4, 12, and 24 weeks. At mean follow-up of 30 weeks in the VMT group with nOCM, the mean LogMAR VA improved significantly from 0.44 to 0.28 (p = 0.0068, paired t-test). Three were no serious adverse events.This study reports improved efficacy of intravitreal ocriplasmin for both VMT and FTMH, and is more favourable in patients with no ocular co-morbidity. We highlight the importance of careful patient selection and structured standard of care pathways to identify patients who will benefit from the positive visual and anatomical effects of intravitreal ocriplasmin

Case study of VMT and macular hole.

<p>This 60 year old female patient was diagnosed with right VMT and FTMH (357 microns), she had suffered for 2–3 months with blurred and distorted vision and was very symptomatic, the absence of ERM was confirmed. Vision prior to ocriplasmin injection was R 6/36, L 6/18. The patient was treated with ocriplasmin according to standard MEH protocols and followed up as standard of care. FTMH closed after one week. Vision at Month 7 was 6/24.</p

Baseline demographics and ocular characteristics.

<p>Baseline demographics and ocular characteristics.</p