Sodium Fluorescein as an Optical Label to Evaluate Subretinal Injection.

PURPOSE: There is renewed interest in subretinal drug delivery as the result of novel and emerging treatments for retinal diseases, including retinal gene therapy. However, our knowledge of the distribution of subretinally delivered drugs is incomplete; herein, we describe a qualitative and quantitative means of surveying the early intraocular distribution of subretinally delivered drugs using dilute sodium fluorescein (NaFl). METHODS: Sodium fluorescein 10% was serially diluted and mixed with a solution containing tissue plasminogen activator (tPA) at a final concentration of 0.1 mg/mL NaFl and 0.5 mg/mL of tPA. Because this solution was to be used in the context of subretinal tPA injection in the treatment of subretinal hemorrhage, fluorophotometry with, and without, the presence of human whole blood was performed to derive a formula to calculate the concentration of NaFl based on the fluorescence of aspirated intraocular fluid. Videos of subretinal tissue plasminogen activator surgery in a case are presented as a qualitative demonstration of the technique and vitreous cavity fluid collected at case completion underwent fluorophotometry to estimate the loss of therapeutic solution. RESULTS: Although the presence of hemoglobin in blood suppresses fluorescence of NaFl, we demonstrate that centrifuging admixtures of blood with NaFl negates the optical effects of blood and yields identical fluorescence versus concentration plots to those of NaFl solution alone. We also demonstrate that NaFl at 0.1 mg/mL can be readily used to qualitatively assess drug losses before, during, and after subretinal injection. Furthermore, we describe how it may be used to quantitatively estimate the total loss of therapeutic solution during subretinal injection using fluorophotometry on aspirated fluid from the vitreous cavity (loss estimated as 4% in the case presented). CONCLUSION: Sodium fluorescein at a concentration of 0.1 mg/mL can be used to quantitatively and qualitatively assess the fate of subretinally injected drugs during subretinal injection surgery.

Intracameral r-tPA for the management of severe fibrinous reactions in TASS after cataract surgery.

BACKGROUND: To describe the use of intracameral recombinant tissue plasminogen activator (r-tPA) in the treatment of severe fibrinous reactions in toxic anterior segment syndrome (TASS) after cataract surgery. METHODS: A case series of 59 eyes of 59 patients with severe fibrinous anterior chamber reaction following cataract surgery who received intracameral r-tPA (25 µg/0.1 ml). The main outcome measures after intracameral r-tPA were the incidence of complete fibrinolysis, time of maximal effect, visual acuity, and complications. RESULTS: Severe fibrinous reactions appeared 11.5 ± 5.3 days after cataract surgery. Fibrinolysis was observed 2.33 ± 2.70 days after rtPA use and 36 eyes (61%) exhibited resolution of the fibrin by the end of the first day following injection (p < 0.001). Transient corneal edema observed at 1-day after injection was the only complication reported during the injection of r-tPA or at follow-up. Eight eyes (13.6%) required a second r-tPA injection. Best-corrected visual acuity improved from 0.88 ± 0.67 logMAR units before rtPA injection to 0.48 ± 0.49 logMAR units at 1-month (p < 0.001). CONCLUSIONS: The application of r-tPA was a quick and efficacious therapeutic approach for the management of severe fibrinous reactions in TASS after cataract surgery. In a clinical setting, intracameral r-tPA may be useful when rapid visual recovery is needed.

Two-step versus 1-step subretinal injection to compare subretinal drug delivery: a randomised study protocol.

INTRODUCTION: There is increasing interest in subretinal injections as a surgical procedure, largely as a result of emerging treatments for ocular diseases which necessitate this manoeuvre. However, surgical variables in the efficacy of such treatments have to date been largely overlooked and the proportion of drug which reaches the intended compartment of the subretinal space remains unknown. Our aims are twofold: first, to determine the proportion of subretinally injected medication retained following surgical delivery and second, to compare two different techniques of injection ('1-step' vs '2-step'). METHODS: We outline a randomised controlled trial of subretinal injection of alteplase following vitrectomy for the management of submacular haemorrhage secondary to age-related macular degeneration. Patients will be randomised to receive either 1-step injection, where the therapeutic solution simultaneously defines the surgical plane or 2-step injection, where the surgical plane is first identified with balanced salt solution prior to injection of subretinal alteplase, as outlined below. Sodium fluorescein will be used as an optical label to track drug reflux into the vitreous cavity using quantitative protocols established in our laboratory. All patients will undergo fluid air exchange at the completion of surgery, with injection of bevacizumab 1.25 mg and 20% sulfahexafluoride gas as the vitreous substitute (both of which may help improve outcomes). Alteplase, sodium fluorescein and bevacizumab will all be used for off-label indications in the trial. ETHICS AND DISSEMINATION: Ethical approval has been obtained from the South Eastern Sydney Local Health District's Human Research Ethics Committee (HREC 17/092). The results of this trial will be disseminated in peer-reviewed proceedings (associated with conference presentation) and in scholarly journals. TRIAL REGISTRATION NUMBER: ACTRN12619001121156.

SURGICAL RETINAL EXPLANTS AS A SOURCE OF RETINAL PROGENITOR CELLS.

PURPOSE: To describe the novel observation of spontaneously migrating retinal cells from living donor surgical retinal explants that express progenitor cell markers in the absence of exogenous growth factors. METHODS: Surgical retinal explants were harvested from 5 consecutive patients undergoing 23 G pars plana vitrectomy for the management of rhegmatogenous detachment. During surgery, equatorial flap tears were trimmed with the vitreous cutter and aspirated. Excised tissue was then regurgitated into a syringe containing balanced salt solution and immediately transferred to tissue culture. Migrating cells subsequently underwent immunohistochemical staining and their characteristics were compared with those of a spontaneously immortalized Müller stem cell line. RESULTS: Spontaneously migrating cells were observed from samples taken from all 5 patients from Day 2 to 10 after transfer to culture. These cells were found to express embryonic cell markers, including paired box 6 (Pax6), sex-determining region Y-box 2 (Sox-2), nestin, cone-rod homeobox, and cyclin-dependent kinase inhibitor 1B (p27Kip1) as well as proteins consistent with early or retained differentiation down the Müller cell lineage, including glial fibrillary acidic protein and glutamine synthetase. CONCLUSION: After injury, the human equatorial retina is capable of spontaneously producing cells that demonstrate migration and that express progenitor cell markers. In addition, these cells express proteins consistent with Müller cell lineage. These initial observations support the assertion that the human retina may possess the potential for regeneration and that surgical retinal explants could also act as a ready source of retinal progenitor cells.

Ocular injuries incurred by Israeli defense forces during low-intensity conflicts.

BACKGROUND: To describe ocular injuries sustained by Israeli Defense Forces (IDF) soldiers during low-intensity conflicts from 1998 to 2017, and to evaluate the use of protective eyewear. METHODS: Retrospective analysis of data retrieved from two tertiary Israeli medical centers and the military trauma registry. The analysis included all IDF soldiers with ocular injuries who were referred to these centers between 1998 and 2017. Data on injury type, the use of protective eyewear, and interventions were retrieved and analyzed. Additional data regarding the use of protective eyewear and ocular injuries in 108 patients with head and neck injuries in one operation was analyzed. RESULTS: A total of 126 soldiers, all males, mean age 22 (SD 5.3) years, sustained ocular injuries during low-intensity conflicts and treated at one of the two participating medical centers. Blast was the most common type of injury (n = 70/126, 56%), followed by shrapnel (n = 37/126, 29%) and gunshot wound (n = 12/126, 9%). The Birmingham Eye Trauma Terminology System (BETTS) injury pattern disclosed lamellar laceration (n = 34/126, 27%), intraocular foreign body (n = 27/126, 21%), penetrating (n = 10/126, 8%), and perforating (n = 7/126, 6%) injuries. Average VA improved from 20/140 at presentation to 20/60 after surgical or conservative intervention, the median VA improved from 20/40 to 20/30 (P < 0.001). Forty-nine patients (49/126, 39%) had poor visual outcome. The mean follow-up lasted 22 (SD 31) months. The use of protective eyewear was correlated with better initial VA(20/30 vs 20/217, P = 0.07). Among 108 patients with head and neck injuries, there was a higher rate of ocular injuries in the group of patients who did not use protective eyewear (n = 26/73, 36% vs n = 4/35, 11%, P = 0.016). CONCLUSIONS: Ocular injuries are common occurrences in low-intensity conflicts. The use of protective eyewear significantly reduces these injuries and should be mandatory. LEVEL OF EVIDENCE: III, prognostic.

Ab-externo drainage with continuous anterior chamber infusion for non-resolving exudative retinal detachment: a case report.

BACKGROUND: Drainage of exudative retinal detachment may be necessary for either therapeutic or diagnostic purposes (or both). Here, we describe an external drainage technique for non-resolving vision-threatening exudative retinal detachment which combines the advantages of internal drainage (widefield viewing and intraocular pressure control using continuous anterior chamber infusion) with those of external drainage (drainage of sub-retinal fluid without vitrectomy). CASE PRESENTATION: To illustrate this technique, we present a 13-year-old girl with macula-off exudative retinal detachment secondary to Vogt-Koyanagi-Harada syndrome, which was unresponsive to aggressive medical management. External drainage was undertaken using widefield viewing and chandelier illumination. Intraocular pressure was maintained with an anterior chamber infusion. Near-complete drainage of sub-retinal fluid was achieved, and retinal reattachment was maintained at 6 months postoperatively, with a corresponding improvement in visual acuity from 20/63 to 20/40. CONCLUSIONS: External drainage under chandelier-assisted viewing at the surgical microscope with anterior chamber infusion offers the ergonomic and optical advantages of the surgical microscope and widefield visualisation, continuous IOP control and drainage of sub-retinal fluid without the need for pars plana vitrectomy.

Ocular morbidity in natural disasters: field hospital experience 2010-2015.

PURPOSE: To determine the characteristics of ocular injuries treated by Israel Defense Forces (IDF) field hospital following three natural disasters: the 2010 earthquake in Haiti, the 2013 typhoon in the Philippines, and the 2015 earthquake and avalanche in Nepal. The purpose was to provide data, which would assist allocation of ocular resources for future disasters. DESIGN: Retrospective database study. METHODS: Ocular clinical data collected from the IDF database. Time postdisaster was divided into three periods: 4-8, 9-12, and 13-16 days. Diagnoses were categorized as disaster-related (DRD), defined as directly resulting from the disaster (mostly ocular trauma), and nondisaster-related (NDRD), defined as preexisting conditions or results of postevent living conditions problems. RESULTS: The field hospitals began functioning 3-8 days after the disaster and continued for 10.3 ± 1.5 days. Ocular conditions were treated in 265 (4.9%) of the total 5356 patients. Sixty-five cases were DRD and 200 were NDRD. Around day 9 postdisaster the predominant ocular referral changed from DRD to NDRD. CONCLUSIONS: Deployment of a field hospital to a natural disaster area should take into account the type and geographic location of the disaster as well as the high number of nontraumatic ocular conditions.