Chemical compounds causing severe acute toxicity in heavy liquids used for intraocular surgery.

Perfluorocarbon liquids (PFCLs) have been considered safe for intraocular manipulation of the retina, but since 2013 many cases of acute eye toxicity cousing blindness have been reported in various countries when using various commercial PFCLs. All these PFCLs were CE marked (Conformité Européenne), which meant they had been subjected to evaluation complying with the International Organization for Standardization (ISO) guidelines. These dramatic events raised questions about the safety of PFCLs and the validity of some cytotoxicity tests performed under ISO guidelines. Samples from toxic batches were analyzed by gas chromatography-mass spectrometry combined with Raman and infrared spectrometry. Perfluorooctanoic acid, dodecafluoro-1-heptanol, ethylbenzene and tributyltin bromide were identified and evaluated by a direct contact cytotoxicity test using ARPE-19 cell line, patented by our group (EP 3467118 A1). Perfluorooctanoic acid at a concentration of >0.06 mM and tributyltin bromide at a concentration of ≥0.016 mM were shown to be toxic, whereas the concentration found in the toxic samples reached 0.48 mM, and 0.111 mM, respectively. These finding emphasized the idea that determination of partially fluorinated compounds are not enough to guarantee the safety of these medical devices.

ACUTE RETINAL DAMAGE AFTER USING A TOXIC PERFLUORO-OCTANE FOR VITREO-RETINAL SURGERY.

PURPOSE: To describe a series of retinal acute toxicity cases with severe visual loss after intraocular use of a toxic perfluoro-octane (PFO). The clinical presentation is described, and the likely causes are analyzed. New biological methods for testing safety of intraocular medical devices are proposed. METHODS: Information regarding a series of eyes suffering acute severe events after intraocular use of a toxic PFO was analyzed. Four types of spectroscopy, nuclear magnetic resonance, and chromatography were used to identify the potential PFO contaminants. Cultures of human retinal pigment epithelial cells (ARPE-19) and porcine neuroretina were used to quantify the toxicity of the suspect PFO lots. RESULTS: Of 117 cases of intraocular toxicity, 96 were considered clearly related to the use of PFO. Fifty-three cases had no light perception, and 97 had no measurable visual acuity. Retinal necrosis (n = 38) and vascular occlusion (n = 33) were the most characteristic findings. Two hydroxyl compounds, perfluorooctanoic acid and dodecafluoro-1-heptanol, and benzene derivatives were identified as the suspected toxic agents. While existing toxicity testing failed, we proposed new tests that demonstrated clear toxicity. CONCLUSION: Protocols to determine cytotoxicity of intraocular medical devices should be revised to assure safety. Acute toxic events should be reported to health authorities and scientific media.

Predictive models of long-term anatomic outcome in age-related macular degeneration treated with as-needed Ranibizumab.

BACKGROUND: To analyze predictors and develop predictive models of anatomic outcome in neovascular age-related macular degeneration (AMD) treated with as-needed ranibizumab after 4 years of follow-up. METHODS: A multicenter consecutive case series non-interventional study was performed. Clinical, funduscopic and OCT characteristics of 194 treatment-naïve patients with AMD treated with as-needed ranibizumab for at least 2 years and up to 4 years were analyzed at baseline, 3 months and each year until the end of the follow-up. Baseline demographic and angiographic characteristics were also evaluated. R Statistical Software was used for statistical analysis. Main outcome measure was final anatomic status. RESULTS: Factors associated with less probability of preserved macula were diagnosis in 2009, older age, worse vision, presence of atrophy/fibrosis, pigment epithelium detachment, and geographic atrophy/fibrotic scar/neovascular AMD in the fellow eye. Factors associated with higher probability of GA were presence of atrophy and greater number of injections, whereas male sex, worse vision, lesser change in central macular thickness and presence of fibrosis were associated with less probability of GA as final macular status. Predictive model of preserved macula vs. GA/fibrotic scar showed sensibility of 77.78% and specificity of 69.09%. Predictive model of GA vs. fibrotic scar showed sensibility of 68.89% and specificity of 72.22%. CONCLUSIONS: We identified predictors of final macular status, and developed two predictive models. Predictive models that we propose are based on easily harvested variables, and, if validated, could be a useful tool for individual patient management and clinical research studies.

X-Linked retinoschisis associated to a novel intragenic microdeletion: case report.

BACKGROUND: X-linked retinoschisis is a recessively inherited retinal degeneration. Clinical diagnosis can be challenging due to the highly variable phenotypic presentation. Also, clinical diagnostic tests may be normal at early stages of this condition. Therefore, genetic diagnosis has become a priceless tool in the management of this disease. CASE PRESENTATION: We present a case of a 17-year-old caucasian male with foveal and peripheral schisis, along with Mizuo-Nakamura phenomenon. RS1 sequencing led to the discovery of an in-frame deletion not previously described in the literature. CONCLUSIONS: Genetic deletions causative of X-linked retinoschisis are quite rare, since more than 80 % are caused by misssense mutations. In this particular case, its pathological effect comes from affecting a key element of the retinoschisin, the discoidin domain.

Management of significant reactivation of old disciform scars in wet age-related macular degeneration.

BACKGROUND: Fibrotic disciform scars represent the end-stage of wet age-related macular degeneration (AMD) and ophthalmologists tend not to treat them. However, reactivation can occur resulting in further worsening of patients. The aim of this study is to describe the clinical outcomes of 10 patients with disciform scars from age-related macular degeneration (AMD) that have subsequently reactivated. METHODS: Indocyanine green angiography (ICG) was used to identify the active areas and these "hot spots" (HS) that were subsequently treated with focal laser photocoagulation. RESULTS: In 10 out of 11 patients with potential reactivation of an AMD scar, a treatable HS was found on the ICG at the border of the disciform scar. The identified HS was treated with focal laser photocoagulation. Post treatment these areas became inactive. However in 2 cases, reactivation occurred requiring retreatment a few months later. CONCLUSIONS: AMD patients who are noted to have disciform scars that are increasing in size and signs of activation such as lipid exudation and subretinal haemorrhage should undergo ICG imaging to look for HS. These patients could benefit from focal laser to stabilize the disease and avoid complications and further peripheral visual loss. It is suspected that these patients may have the polypoidal subtype of AMD.

Funduscopic results after 4-year follow-up treatment with ranibizumab for age-related macular degeneration in a region of Spain.

BACKGROUND: The study aims to survey longstanding funduscopic and functional outcomes of age-related macular degeneration (AMD) after ranibizumab treatment and verify the accuracy of a new method to compare the retinal thickness measured with different optical coherence tomography (OCT) tools. METHODS: Case series included 314 eyes with 2-4 years of follow-up. Main Outcome Measures were visual acuity (VA), number of injections, retinal thickness, OCT morphology, and final macular funduscopic status. RESULTS: One hundred twenty-two men and 177 women (mean age, 78.3 years) were included. The mean time to the first injection was 17.3 ± 14.6 days. Initial VA was O.8(20/125) ± 0.5; 0.7(20/100) ± 0.5 at 3 months; 0.8(20/125) ± 0.5 at a year; 1(20/200) ± 0.6 at year 2; 1(20/200) ± 0.6 at year 3 and 1.1(20/250) ± 0.6 at year 4. Number of visits at 3 months was 2.7 ± 0.8; 7.3 ± 2.1 at a year; 5.2 ± 2.7 along the 2nd year; 3.9 ± 2.3 at year 3 and 3.6 ± 2.2 at year 4. Number of injections at 3 months was 2.6 ± 0.5; 3.9 ± 1.5 at a year; 1.1 ± 1.5 along the 2nd year; 1.5 ± 2.4 at year 3 and 1.8 ± 3.1 at year 4. Patients with worse VA outcomes received more injections and were older. The formula to calculate changes in retinal thickness showed a 30% reduction in thickness, which correlated well with the OCT morphology. Patients with polypoidal choroidal vasculopathy (PCV) had a worse final outcome. The final disciform macular status (37%) was related to fewer injections and a greater decrease in thickness. Final well-preserved maculas (12.%) needed more injections and treatment changes; those that were atrophic at the final visit (30.8%) had a worse initial VA and greater decrease in thickness at the 3-month visit. CONCLUSIONS: Younger patients had better final outcomes. Our method to compare retinal thickness using different OCT tools worked well. The final visual outcome after a long follow-up was poor, which may be related to advanced age, poor initial VA, and the high incidence of final fibrosis or atrophy.

External validation of existing formulas to predict the risk of developing proliferative vitreoretinopathy: the Retina 1 Project; report 5.

PURPOSE: To externally validate the accuracy of previously published formulas for predicting proliferative vitreoretinopathy development after retinal detachment surgery. METHODS: Clinical variables from consecutive retinal detachment patients (n = 1,047) were collected from the Retina 1 Project conducted in 17 Spanish and Portuguese centers. These data were used for external validation of four previously published formulas, F1 to F4. Receiver-operating characteristic curves were used to validate the quality of formulas, and measures of discrimination, precision, and calibration were calculated for each. Concordance among the formulas was determined by Cohen kappa index. RESULTS: The areas under the receiver-operating characteristic curves were as follows: F1, 0.5809; F2, 0.5398; F3, 0.5964; and F4, 0.4617. F1 had the highest accuracy, 74.21%. Almost 19% of proliferative vitreoretinopathy cases were correctly classified by F1 compared with 13%, 15%, and 10% for F2, F3, and F4, respectively. There was moderate concordance between F2 and F3 but little between the other formulas. CONCLUSION: After external validation, none of the formulas were accurate enough for routine clinical use. To increase its usefulness, other factors besides the clinical ones considered here should be incorporated into future formulas for predicting risk of developing proliferative vitreoretinopathy.

Pathology associated with optical coherence tomography macular bending due to either dome-shaped macula or inferior staphyloma in myopic patients.

PURPOSE: To evaluate the prevalence of and describe the pathology associated with macular bending (MB) defined as a smooth macular elevation found in optical coherence tomography (OCT) of patients with high myopia related to either dome-shaped macula (DSM) or the border of an inferior staphyloma. PROCEDURES: We reviewed the 330 files of all highly myopic patients in our database that had had an OCT performed in the last 5 years. Main outcome measures were MB prevalence and its associated pathology. RESULTS: Sixty-eight eyes from 45 patients (13.63%) presented MB; 23 bilateral, 40 in a posterior pole or macular staphyloma and 21 in an inferior staphyloma. Eighteen eyes presented choroidal neovascularization (CNV), 7 subretinal fluid without CNV, 11 retinoschisis and 3 a macular hole which had been stable for years. No differences were found in the rate of complications between patients with DSM or inferior staphyloma. CONCLUSIONS: MB is not an uncommon clinical feature. Associated pathology prevalence in MB was elevated and similar in posterior and inferior staphylomas.

Retinal pigment epithelium tears in age-related macular degeneration treated with antiangiogenic drugs: a controlled study with long follow-up.

PURPOSE: To study whether anti-vascular endothelial growth factor (VEGF) therapy improves visual acuity (VA) in patients with exudative age-related macular degeneration (AMD) complicated with retinal pigment epithelium (RPE) tears. METHODS: Retrospective case-control series. Group I (control group) included 9 patients with RPE tears that received no treatment, and group II (intervention group) incorporated 12 patients treated with anti-VEGF. RESULTS: A statistically significant difference was found in VA between the groups from the 3rd month to the final follow-up (p = 0.034). Final VA improved in the treatment group (p = 0.015). No differences were found in central macular thickness between the groups either before or after treatment. Mean number of injections in group II was 5.75 (SD = 1.19). Most patients presented a grade 3 rip. All lesions were inactive at the end of follow-up in group II and 1 remained active in group I. The number of final atrophic/disciform scars was 6/8 in group I and 7/5 in group II. CONCLUSIONS: RPE tears treated with antiangiogenic drugs experienced functional benefit. To the authors' knowledge, this is the first controlled series reporting effectiveness of suppression of neovascular activity with antiangiogenic treatment after RPE rip in AMD.

Silicone microbubbles after anti-vascular endothelial growth factor injections in patients with wet age-related macular degeneration: incidence, quantification and secondary optical coherence tomography artfacts.

PURPOSE: To report the incidence and quantity of silicone oil microbubbles and the relationship with the number of intravitreal anti-vascular endothelial growth factor (VEGF) injections and evaluate if microbubbles induce artefacts on optical coherence tomography (OCT) images. METHODS: Observational, descriptive, cross-sectional study. Patients with wet age-related macular degeneration were included who had been treated for 1 year minimally with anti-VEGF injections repackaged in the hospital pharmacy. Detection and quantification of silicone microbubbles by mydriatic biomicroscopic examination were conducted 1 month after the last injection. The numbers of microbubbles were quantified on a scale of 0-3: 0, none; 1 scarce (1-10 microbubbles); 2 moderate (10-30); or 3 numerous (>30). Shadowing on OCT images was classified as 0-3: 0, none; 1 obscuring some retinal layers; 2 obscuring all retinal layers; or 3 obscuring the retinal thickness. RESULTS: The study included 142 eyes of 98 patients (mean age, 82.4 years + 7.3; range, 65-97) treated with 2377 injections. Microbubbles were detected in 127 (89.4%) eyes, 62 (43.6%) with numerous microbubbles and 36 (25.4%) and 29 (20.4%), respectively, with scarce and moderate numbers. A positive correlation was found between the numbers of injections and intravitreal silicone (rho, 0.7). Optical coherence tomography (OCT) artefacts were detected in 11 eyes; the artefacts obscured all retinal layers in three eyes. No significant relationship could be established between the appearance of floaters and the microbubbles. CONCLUSION: The presence and number of silicone microbubbles were correlated with the number of intravitreal injections. Microbubbles can produce OCT artefacts, which can hinder the treatment decision.

A strong genetic association between the tumor necrosis factor locus and proliferative vitreoretinopathy: the retina 4 project.

OBJECTIVE: To assess the genetic contribution to proliferative vitreoretinopathy (PVR) and report the strong association observed in the tumor necrosis factor (TNF) locus. DESIGN: As a component of The Retina 4 Project, a case-controlled, candidate gene association study in the TNF locus was conducted. PARTICIPANTS AND CONTROLS: Blood from 450 patients with (138 cases) and without (312 controls) post-rhegmatogenous retinal detachment (RD) PVR was genotyped to determine polymorphisms located in the TNFα gene. METHODS: Single nucleotide polymorphisms (SNPs) with correlation coefficients of ≥ 0.8 and a minor allelic frequency of ≥ 10% were studied. Functional SNPs or SNPs previously described in association with other inflammatory diseases were also added for analysis. The SNPlex Genotyping System (Applied Biosystems, Foster City, CA) was used for genotyping. Single nucleotide polymorphism and haplotype analyses were performed. Bioinformatic tools were used to evaluate those SNPs that were significantly associated. MAIN OUTCOME MEASURES: Single and haplotypic significant associations with PVR. RESULTS: A total of 11 common tag SNPs in the following genes were analyzed: lymphotoxin alpha (LTA), TNFα, leukocyte-specific transcript 1 (LST1), and the activating natural killer receptor p30 (NCR3). After permutation, there was a significant association in the non-synonymous polymorphism rs2229094(T→C) in the LTA gene (P = 0.0283), which encodes a cysteine to arginine change in the signal peptide. This marker was also present in all significant haplotypic associations and was not observed in any nonsignificant associations. When this SNP was analyzed using bioinformatic tools, the hydropathy profile changed, as well as the transmembrane region and the splicing site predictions. CONCLUSIONS: The strong association found in the rs2229094(T→C) of the LTA gene may indicate an important role of this polymorphism in the development of PVR. If supported in extended studies, the rs2229094(T→C) may have significant implications regarding the genetic risk of the retinal repairing process.

PRPH2 (Peripherin/RDS) mutations associated with different macular dystrophies in a Spanish population: a new mutation.

PURPOSE: To assess the occurrence of PRPH2 mutations in patients presenting macular dystrophies and to describe their phenotype-genotype correlation. METHODS: A total of 32 sporadic cases and 13 individuals from 5 families were studied. The patients presented early onset drusen, suspected pattern dystrophy (including adult-onset foveomacular vitelliform dystrophy [AOFVD]), or any presumed macular dystrophy producing neovascularization or atrophic changes documented before patients reached 50 years of age. In case of atrophy, this could be confined to the macula, which was considered to be central areolar choroidal dystrophy (CACD), or extend to the midperiphery of the retina, which we called diffuse macular dystrophy (DMD). Clinical workup and analysis of PRPH2, EFEMP1, and TIMP3 genes were done. RESULTS: Four mutations of the PRPH2 gene were found in 3 sporadic cases and 3 families (n = 11). A p.R46X mutation, previously described in CACD, was found in 3 members of a family with AOFVD and in a sporadic case with DMD. A p.L45F mutation, described before in retinitis pigmentosa, was found in a sporadic case of AOFVD. A p.R195L mutation previously described in CACD was found in 2 members of a family with CACD. The latter was found in a family and a sporadic case (from the same village as the family) and all of them presented DMD. A new p.V2091 mutation was found in a patient with AOFVD. CONCLUSIONS: New phenotypes were found for known mutations. No phenotype variation was observed in the members of the 3 families. A new mutation in PRPH2 gene was found.

Intravitreal stem cell paracrine properties as a potential neuroprotective therapy for retinal photoreceptor neurodegenerative diseases.

Retinal degenerations are the leading causes of irreversible visual loss worldwide. Many pathologies included under this umbrella involve progressive degeneration and ultimate loss of the photoreceptor cells, with age-related macular degeneration and inherited and ischemic retinal diseases the most relevant. These diseases greatly impact patients' daily lives, with accompanying marked social and economic consequences. However, the currently available treatments only delay the onset or slow progression of visual impairment, and there are no cures for these photoreceptor diseases. Therefore, new therapeutic strategies are being investigated, such as gene therapy, optogenetics, cell replacement, or cell-based neuroprotection. Specifically, stem cells can secrete neurotrophic, immunomodulatory, and anti-angiogenic factors that potentially protect and preserve retinal cells from neurodegeneration. Further, neuroprotection can be used in different types of retinal degenerative diseases and at different disease stages, unlike other potential therapies. This review summarizes stem cell-based paracrine neuroprotective strategies for photoreceptor degeneration, which are under study in clinical trials, and the latest preclinical studies. Effective retinal neuroprotection could be the next frontier in photoreceptor diseases, and the development of novel neuroprotective strategies will address the unmet therapeutic needs.

Acute retinal toxicity associated with a mixture of perfluorooctane and perfluorohexyloctane: failure of another indirect cytotoxicity analysis.

AIMS: To report new information related to acute retinal toxicity of Bio Octane Plus, a mixture of 90% perfluorooctane (PFO) and 10% perfluorohexyloctane. METHODS: This retrospective, descriptive case series reports the occurrence of acute retinal toxicity after vitreoretinal surgery in which Bio Octane Plus (batch number 1605148) was used as an endotamponade. Cytotoxicity biocompatibility tests and chemical analyses by Fourier-transformed infrared (FTIR) spectroscopy and gas chromatography-mass spectrometry (GC-MS) of the presumed toxic product were performed. RESULTS: Four patients presented with acute severe visual loss after uneventful ocular surgery assisted by Bio Octane Plus (batch number 1605148) as endotamponade. Patients experienced extensive retinal vascular occlusion leading to retinal and optic nerve atrophy. The viability of ARPE-19 cells directly exposed to the suspect batch for 30 min was 0%. The agarose overlay method used by the manufacturer according to European Union regulations and International Organization for Standardization (ISO) International Standards failed to detect toxicity. FTIR spectroscopy showed small differences between the non-toxic and toxic batches. GC-MS analysis showed the presence of bromotributyl stannane (whose toxicity was demonstrated in the dose-response curve) only in the toxic batch of Bio Octane Plus. CONCLUSION: This is the third report of retinotoxicity due to PFO in 4 years. The clinical profiles may be missed as they resemble other postsurgical complications; therefore, more cases worldwide could have gone unreported. Protocols to determine cytotoxicity of intraocular medical devices and approved by the ISO International Standards based on indirect methods have failed and should be revised to ensure safety.

Comparison between direct contact and extract exposure methods for PFO cytotoxicity evaluation.

A series of recent acute blindness cases following non-complicated retinal detachment surgery caused the release of several health alerts in Spain. The blindness was attributed to certain lots of perfluoro-octane (PFO; a volatile and transient medical device). Similar cases have been reported in other countries. This has raised questions regarding the validity of cytotoxicity test methods currently used to certify the safety of PFO lots. The tests were performed according to the International Organization for Standardization (ISO) norms, using the extract dilution method or the indirect contact method as applied to L929 cells, a line derived from mouse fibroblasts. The limitations of those methods have been resolved in this study by proposing a new cytotoxicity test method for volatile substances. The new method requires direct contact of the tested substance with cells that are similar to those exposed to the substance in the clinical setting. This approach includes a few new technical steps that are crucial for detecting cytotoxicity. Our new method detected toxic PFO lots that corresponded to the lots producing clinical blindness, which previous methods failed to detect. The study suggests applying this new method to avoid occurrence of such cases of blindness.

Atypical myopic retinoschisis.

A 34-year-old woman with a refraction of-11 diopters in both eyes presented with a central scotoma and metamorphopsia in her right eye related to a juxtafoveal hemorrhage. Fluorescein angiography ruled out choroidal neovascularization and lacquer cracks. Optical coherence tomography revealed retinal splitting in the juxtafoveal area and the peripapillary area. No ophthalmoscopic peripheral abnormalities were observed. This is an atypical example of schisis associated with myopia because it was symptomatic, associated with hemorrhage, and did not affect the fovea. This may be an extension to the macula of a subclinical peripheral retinoschisis that became progressive and symptomatic due to vitreous tractional forces.

Photodynamic therapy for subfoveal and juxtafoveal choroidal neovascularization associated with punctate inner choroidopathy.

PURPOSE: To evaluate the treatment of subfoveal and juxtafoveal choroidal neovascularization (CNV) using verteporfin photodynamic therapy (vPDT) in patients affected by punctate inner choroidopathy (PIC). METHODS: A chart review of 8 patients with CNV associated with PIC treated with vPDT was done. RESULTS: The 8 patients (8 eyes) included 4 men and 4 women with a mean age of 30.9 years. Six of them presented juxtafoveal CNVs, and two had subfoveal CNVs, at presentation. Mean follow-up time was 22.7 months. The VA improved in five eyes, and three eyes declined. One patient developed a new CNV a few days after vPDT, and one had multiple CNVs at presentation. Two of the 3 patients with longer follow-up period presented late recurrences. CONCLUSIONS: vPDT is a beneficial resource in stabilizing and also improving VA in PIC patients affected with subfoveal and juxtafoveal CNV, although one third of the patients retain poor visual acuity.