Optical Absorption Properties in Pentacene/Tetracene Solid Solutions.

Modifying the optical and electronic properties of crystalline organic thin films is of great interest for improving the performance of modern organic semiconductor devices. Therein, the statistical mixing of molecules to form a solid solution provides an opportunity to fine-tune optical and electronic properties. Unfortunately, the diversity of intermolecular interactions renders mixed organic crystals highly complex, and a holistic picture is still lacking. Here, we report a study of the optical absorption properties in solid solutions of pentacene and tetracene, two prototypical organic semiconductors. In the mixtures, the optical properties can be continuously modified by statistical mixing at the molecular level. Comparison with time-dependent density functional theory calculations on occupationally disordered clusters unravels the electronic origin of the low energy optical transitions. The disorder partially relaxes the selection rules, leading to additional optical transitions that manifest as optical broadening. Furthermore, the contribution of diabatic charge-transfer states is modified in the mixtures, reducing the observed splitting in the 0-0 vibronic transition. Additional comparisons with other blended systems generalize our results and indicate that changes in the polarizability of the molecular environment in organic thin-film blends induce shifts in the absorption spectrum.

Modulating Singlet Fission by Scanning through Vibronic Resonances in Pentacene-Based Blends.

Vibronic coupling has been proposed to play a decisive role in promoting ultrafast singlet fission (SF), the conversion of a singlet exciton into two triplet excitons. Its inherent complexity is challenging to explore, both from a theoretical and an experimental point of view, due to the variety of potentially relevant vibrational modes. Here, we report a study on blends of the prototypical SF chromophore pentacene in which we engineer the polarizability of the molecular environment to scan the energy of the excited singlet state (S1) continuously over a narrow energy range, covering vibrational sublevels of the triplet-pair state (1(TT)). Using femtosecond transient absorption spectroscopy, we probe the dependence of the SF rate on energetic resonance between vibronic states and, by comparison with simulation, identify vibrational modes near 1150 cm-1 as key in facilitating ultrafast SF in pentacene.

DIDANOSINE RETINAL TOXICITY.

PURPOSE: To report nine new cases of retinal degeneration secondary to didanosine toxicity and to summarize the previously reported cases in the literature. METHODS: This was a multicenter, retrospective, observational case study from seven institutions. Medical records of patients who demonstrated well-demarcated severe midperipheral chorioretinal degeneration and who were previously treated with didanosine therapy were collected and the following information was reviewed: age, gender, medical history, detailed medication history including current and previous antiretroviral use, ocular and retinal examination findings, and multimodal imaging findings with optical coherence tomography, fundus photography, wide-field fundus autofluorescence, and wide-field fluorescein angiography. When available, findings with electrophysiology testing and automated perimetry were also collected and reviewed. A literature review was also performed to collect all reported cases of chorioretinal degeneration secondary to didanosine toxicity. RESULTS: Nine patients were identified who had findings consistent with peripheral retinal toxicity secondary to didanosine use. Eight of the 9 patients were men, and the median age was 54 years at the time of presentation (mean: 55 years, range, 42-71 years). Snellen distance acuity ranged from 20/20 to 20/32. At least three of the cases in the series demonstrated progression of the peripheral retinal pigment epithelium and photoreceptor atrophy despite didanosine cessation. A review of the literature revealed 10 additional cases of didanosine toxicity. Seven of the 10 cases were in men (70%), and the average age was 26 years with a wide range (2-54 years). Chorioretinal findings were very similar to this cohort. CONCLUSION: Herein, we report the largest series of nine cases of peripheral chorioretinal degeneration secondary to didanosine toxicity in adults. When combined with the cases in the literature, 19 cases of didanosine toxicity, 4 of which occurred in children, were collected and analyzed. Three of the new cases presented showed clear progression of degeneration despite didanosine cessation. Newer nucleoside reverse transcriptase inhibitors may potentiate mitochondrial DNA damage and lead to continued chorioretinal degeneration.

En face spectral domain optical coherence tomography analysis of lamellar macular holes.

PURPOSE: To analyze the anatomical characteristics of lamellar macular holes using cross-sectional and en face spectral domain optical coherence tomography. METHODS: Forty-two lamellar macular holes were retrospectively identified for analysis. The location, cross-sectional length, and area of lamellar holes were measured using B-scans and en face imaging. The presence of photoreceptor inner segment/outer segment disruption and the presence or absence of epiretinal membrane formation were recorded. RESULTS: Forty-two lamellar macular holes were identified. Intraretinal splitting occurred within the outer plexiform layer in 97.6% of eyes. The area of intraretinal splitting in lamellar holes did not correlate with visual acuity. Eyes with inner segment/outer segment disruption had significantly worse mean logMAR visual acuity (0.363 ± 0.169; Snellen = 20/46) than in eyes without inner segment/outer segment disruption (0.203 ± 0.124; Snellen = 20/32) (analysis of variance, P = 0.004). Epiretinal membrane was present in 34 of 42 eyes (81.0%). CONCLUSION: En face imaging allowed for consistent detection and quantification of intraretinal splitting within the outer plexiform layer in patients with lamellar macular holes, supporting the notion that an area of anatomical weakness exists within Henle's fiber layer, presumably at the synaptic connection of these fibers within the outer plexiform layer. However, the en face area of intraretinal splitting did not correlate with visual acuity, disruption of the inner segment/outer segment junction was associated with significantly worse visual acuity in patients with lamellar macular holes.

A national survey of practice patterns: temporal artery biopsy.

OBJECTIVE: To assess current clinical practice patterns for temporal artery biopsy (TAB) among clinicians in establishing the diagnosis of giant cell arteritis. DESIGN: A survey was sent via e-mail using the Survey Monkey website (www.surveymonkey.com; accessed January 24, 2013). The survey initially was sent in July 2010 and continued through October 2010. PARTICIPANTS: The survey was sent via e-mail to the members and affiliates of the American Society of Ophthalmic Plastic and Reconstructive Surgery, the North American Neuro-Ophthalmology Society, and the American College of Rheumatology. METHODS: Data from the survey were collected via Survey Monkey and data analysis was performed using the Fisher exact test and Wilcoxon rank-sum test. MAIN OUTCOME MEASURES: Response to the survey questions on primary unilateral versus bilateral biopsy, performing second-side biopsy if first side results were negative, and the duration for which biopsy findings are reliable after initiating immunosuppressive therapy. RESULTS: The self-described primary subspecialty of the 1074 respondents was as follows: oculoplastic surgery (n = 127), neuro-ophthalmology (n = 119), rheumatology (n = 799), and other (n = 28). Overall, 66% of respondents advocated initial unilateral TAB, 18% advocated bilateral biopsy in all cases, and 16% recommended either unilateral or bilateral TAB depending on the degree of clinical suspicion. Rheumatologists were 4.5 times more likely to advocate initial bilateral biopsy than neuro-ophthalmologists or oculoplastic surgeons (P<0.0001, Fisher exact test). Most respondents believed that biopsy results were accurate for more than 14 days. These results were not affected by stratification of years in practice by the Kruskal-Wallis rank-sum test. CONCLUSIONS: Temporal artery biopsy practices vary greatly among treating physicians. This lack of consensus underscores the need for a systematic assessment of varying practice patterns. FINANCIAL DISCLOSURE(S): The author(s) have no proprietary or commercial interest in any materials discussed in this article.

The real-world efficacy and safety of faricimab in neovascular age-related macular degeneration: the TRUCKEE study - 6 month results.

BACKGROUND/OBJECTIVE: Investigate real-world patients receiving faricimab for the treatment of neovascular age-related macular degeneration (nAMD). SUBJECTS/METHODS: Multicenter, retrospective chart review was conducted on patients treated with faricimab for nAMD from February 2022 to September 2022. Collected data includes background demographics, treatment history, best-corrected visual acuity (BCVA), anatomic changes, and adverse events as safety markers. The main outcome measures are changes in BCVA, changes in central subfield thickness (CST) and adverse events. Secondary outcome measures included treatment intervals and presence of retinal fluid. RESULTS: After one injection of faricimab, all eyes (n = 376), previously-treated (n = 337) and treatment-naïve (n = 39) eyes demonstrated a + 1.1 letter (p = 0.035), a + 0.7 letter (p = 0.196) and a + 4.9 letter (p = 0.076) improvement in BCVA, respectively, and a - 31.3 µM (p < 0.001), a - 25.3 µM (p < 0.001) and a - 84.5 µM (p < 0.001) reduction in CST, respectively. After three injections of faricimab, all eyes (n = 94), previously-treated (n = 81) and treatment-naïve (n = 13) eyes demonstrated a + 3.4 letter (p = 0.03), a + 2.7 letter (p = 0.045) and a + 8.1 letter (p = 0.437) improvement in BCVA, and a - 43.4 µM (p < 0.001), a - 38.1 µM (p < 0.001) and a - 80.1 µM (p < 0.204) reduction in CST, respectively. One case of intraocular inflammation was observed after four injections of faricimab and resolved with topical steroids. One case of infectious endophthalmitis was treated with intravitreal antibiotics and resolved. CONCLUSIONS: Faricimab has demonstrated improvement or maintenance of visual acuity for patients with nAMD, along with rapid improvement of anatomical parameters. It has been well-tolerated with low incidence of treatable intraocular inflammation. Future data will continue to investigate faricimab for real-world patients with nAMD.

Risk factors for retinal detachment following cataract surgery.

PURPOSE OF REVIEW: To review and evaluate the current literature on the incidence and risk factors for rhegmatogenous retinal detachment (RRD) following cataract surgery. RECENT FINDINGS: RRD is a serious complication of cataract surgery that can occur in the early or late postoperative periods. Identifying factors that increase the risk of pseudophakic retinal detachment can aid in management. Recent studies support long established risk factors for retinal detachment including intraoperative complications such as posterior capsular rupture (PCR). In addition, the current literature further defines the risk for pseudophakic retinal detachment associated with younger age at time of surgery, high myopia, and male sex in several large retrospective studies. Two recent articles also examine the state of the vitreous before and after cataract surgery and find that patients are more likely to develop posterior vitreous detachment postoperatively, possibly contributing to the increased risk of RRD. SUMMARY: Younger age, high myopia, and male sex continue to be associated with higher risk of pseudophakic retinal detachment. Intraoperative complications such as PCR also increase the retinal detachment risk. Given the high volume of cataract surgeries performed each year, pseudophakic retinal detachment contributes significantly to visual morbidity in the United States and Europe.

The decline of pneumococcal resistance after cessation of mass antibiotic distributions for trachoma.

After 6 biannual mass distributions of oral azithromycin for trachoma in Ethiopian communities, 76.8% (95% confidence interval [CI], 66.3%-85.1%) of nasopharyngeal Streptococcus pneumoniae isolates from children aged 1-5 years were resistant to macrolides. Twelve and 24 months after the last azithromycin treatment, resistance decreased to 30.6% (95% CI, 18.8%-40.4%; P <.001 ) and 20.8% (95% CI, 12.7%-30.7%; P < .001), respectively. Macrolide resistance decreases after antibiotic pressure is removed.

Retinal arterial occlusive vasculitis following intravitreal brolucizumab administration.

PURPOSE: To describe retinal arterial occlusion and vasculitis following intravitreal brolucizumab administration in a patient with neovascular age-related macular degeneration (nAMD). OBSERVATION: An 88-year-old Caucasian woman with neovascular age-related macular degeneration (nAMD) complained of painless loss of vision with light sensitivity in both eyes (OU) four weeks after bilateral intravitreal brolucizumab. Upon examination, her visual acuity decreased to 20/40 in the right eye (OD) and 20/50 in the left eye (OS). Examination revealed 0.5+ and 1+ anterior chamber cells in OD and OS, respectively. The patient was treated with 1% prednisolone acetate eyedrops in both eyes, and after several weeks, the anterior chamber cells resolved. However, the patient still reported a decline in visual acuity (VA). Fluorescein angiography (FA) revealed retinal arterial occlusion, vasculitis, and optic nerve inflammation in the left eye. Retinal intra-arterial grayish materials were also detected. Laboratory evaluations were performed for common infectious and inflammatory causes and were normal or negative. A delayed inflammatory reaction to brolucizumab was suspected as the cause of the ocular inflammation and retinal vasculitis. An intravitreal dexamethasone implant was inserted into the left eye to treat the inflammation. One week after the dexamethasone implant, VA improved to 20/40 in OU; FA showed improvement, but residual peri-vascular leakage remained. CONCLUSION: Medication-associated uveitis is a rare adverse effect that can lead to vision loss. The index report illustrates a case of intraocular inflammation, retinal arterial vaso-occlusion and vasculitis associated with intravitreal brolucizumab. The delay in developing uveitis suggests that the inflammation is due to a delayed hypersensitivity reaction which can occur several days or weeks after administration of the inciting agent. Recently, several cases of uveitis and vasculitis associated with brolucizumab have been presented and those cases have similar features compared to the index case (1). Therapy with steroids (either intraocular or systemic), after infectious etiologies have been excluded, may be beneficial in halting inflammation and preventing further vision loss.

FANCONI ANEMIA PRESENTING AS BILATERAL DIFFUSE RETINAL OCCLUSIVE VASCULOPATHY.

PURPOSE: To describe the ocular findings and subsequent workup of a 21-year-old woman with previously undiagnosed Fanconi anemia. METHODS: Observational case report and literature review. RESULTS: A 21-year-old healthy woman presented with bilateral retinal hemorrhages, telangiectasia, and severe ischemia with vascular leak. Systemic workup revealed anemia and thrombocytopenia. A diepoxybutane chromosomal breakage test confirmed the diagnosis of Fanconi anemia. CONCLUSION: Ocular complications are common in patients with Fanconi anemia and may be the presenting manifestation of the disease.

Rhegmatogenous Retinal Detachment in Patients with Acute Syphilitic Panuveitis.

PURPOSE: To describe the clinical characteristics and surgical management of rhegmatogenous retinal detachment (RD) in patients with acute syphilitic panuveitis. METHODS: Retrospective case series and comprehensive literature review. RESULTS: Including present and previously reported cases, we identified 11 eyes in 8 patients with acute syphilitic panuveitis that developed a rhegmatogenous RD. Seven of 11 eyes (63.6%) were repaired with a combined scleral buckling, vitrectomy, and endolaser photocoagulation surgery; 1 eye (9.1%) was repaired with scleral buckling only; and 2 eyes (18.2%) with vitrectomy only. Cryotherapy was used to treat a giant retinal tear in 1 eye (9.1%). Four eyes (36.4%) redetached and 3 underwent a second vitrectomy surgery. CONCLUSIONS: Although uncommon, rhegmatogenous RD can occur in patients with moderate to severe acute syphilitic panuveitis. We believe scleral buckling, vitrectomy, endolaser photocoagulation, and silicone oil tamponade give the best chance for successful retinal reattachment.

SUSAC SYNDROME.

PURPOSE: To describe an atypical presentation of Susac syndrome. METHODS: Observational case report. RESULTS: A 44-year-old man with no significant medical history presented with inferonasal visual field loss in his left eye of several months of duration. He was found to have bilateral migratory arteritis with focal areas of arteriolar occlusion in both eyes and peripheral ischemia superotemporally in his left eye. An extensive hematologic workup was negative for autoimmune disease or coagulopathy. Magnetic resonance imaging with contrast of his brain revealed a hyperintense lesion in the splenium of the corpus callosum. Auditory testing was significant for nonspecific high-frequency hearing loss in the right ear. Given the full clinical picture, a diagnosis of Susac syndrome was made. CONCLUSION: Susac syndrome is a multisystemic, immune-mediated occlusive endotheliopathy characterized by the clinical triad of encephalopathy, branch retinal artery occlusions, and hearing loss. However, patients may present with varying degrees of this triad; thus, there should be a high index of suspicion in patients presenting with multiple artery occlusions or multifocal arteritis.

Spectral domain optical coherence tomography findings in eyes with acute ischaemic retinal whitening.

Acute retinal ischaemia presents in various forms depending on the type and location of the associated vascular occlusion. Cotton wool spots have been considered one manifestation of ischaemia and represent swelling in the nerve fibre layer. However, clinical retinal whitening also occurs in areas not affected by cotton wool spots, and has distinguishing spectral domain optical coherence tomography (SD-OCT) features. We present SD-OCT findings of hyper-reflectivity and thickening in four eyes with representative retinal arterial or retinal venous occlusions, specifically branch retinal artery occlusion, central retinal vein occlusion, Purtscher-like retinopathy and ophthalmic artery occlusion. The spectrum of retinal ischaemia from various causes was found to manifest in inner nuclear layer hyper-reflectivity and thickening on SD-OCT. En Face OCT imaging further characterises the topographical distribution of ischaemia, and reveals patterns which provide insight into the pathological processes involved.

Clinical presentation of chorioretinitis sclopetaria.

PURPOSE: To report the clinical manifestations of a case of chorioretinitis sclopetaria. METHODS: Observational case report. RESULTS: A 30-year-old prison inmate sustained a traumatic injury to his left eye. Fundus examination showed a large chorioretinal detachment revealing bare sclera, vitreous hemorrhage, and commotio retinae. CONCLUSION: The patient was diagnosed with chorioretinitis sclopetaria. Given the mechanism of injury, retinal detachment is rare. Observation is appropriate as initial management.

Central serous chorioretinopathy after trabeculectomy in a patient with microphthalmos and congenital rubella syndrome.

PURPOSE: To describe a case of central serous chorioretinopathy after trabeculectomy surgery in an eye with microphthalmos in the setting of congenital rubella syndrome. METHODS: A Case report with color fundus photographs, fluorescein angiography, and spectral domain optical coherence tomography. RESULTS: A 46-year-old African American man, with a history of congenital heart disease and bilateral hearing loss, developed persistent vision loss in the left eye after trabeculectomy surgery. Ocular examination revealed bilateral salt-and-pepper retinopathy and a serous detachment in the macula of the left eye. Fluorescein angiography showed an early "smoke-stack" pattern of hyperfluorescence with progressive filling of the subretinal space consistent with central serous chorioretinopathy. Spectral domain optical coherence tomography documented both size and extent of the serous retinal detachment and showed several pigment epithelial detachments. B-scan ultrasonography confirmed the serous retinal detachment on the left but showed no evidence of posterior eye wall thickening or of retrobulbar fluid. An A-scan revealed an axial length of 21.8 mm on the right and 19.7 mm on left eye, confirming microphthalmos and supporting the suspected diagnosis of congenital rubella syndrome. CONCLUSION: Although uncommon, central serous chorioretinopathy can occur in anatomically small eyes after trabeculectomy surgery.

Acute retinal necrosis secondary to multidrug-resistant herpes simplex virus 2 in an immunocompetent adolescent.

PURPOSE: To report the clinical course of a patient with acute retinal necrosis resulting from a multidrug-resistant strain of herpes simplex virus 2. METHODS: Observational case report. RESULTS: A 17-year-old man with no identifiable immune deficiency presented with pain and decreased vision in his left eye. He had dense anterior and posterior segment inflammation with retinal whitening suggestive of acute retinal necrosis, which progressed despite treatment with intravenous acyclovir, methylprednisolone, and ganciclovir. A transition to intravitreal and intravenous foscarnet led to clinical improvement. Genetic analysis revealed the etiology to be a multidrug-resistant strain of herpes simplex virus 2. CONCLUSION: Antiviral resistance is an uncommon finding among viruses causing acute retinal necrosis in immunocompetent patients. Patients with these infections may be adequately treated with prompt recognition and a change in therapy to alternative antiviral agents such as foscarnet.

Cytomegalovirus retinitis in dyskeratosis congenita.

PURPOSE: The purpose of this study was to report a case of cytomegalovirus retinitis in the setting of dyskeratosis congenita. METHODS: Case report and literature review. RESULTS: A 23-year-old woman who had peripheral occlusive retinal vasculopathy and neovascularization as a result of pancytopenia caused by bone marrow failure also developed cytomegalovirus retinitis. She had been diagnosed with dyskeratosis congenita, which had caused the bone marrow failure and pancytopenia. CONCLUSION: Dyskeratosis congenita is a multisystem disorder that causes bone marrow failure. It can have retinal manifestations in the form of peripheral proliferative retinopathy and retinitis.

The fitness cost of antibiotic resistance in Streptococcus pneumoniae: insight from the field.

BACKGROUND: Laboratory studies have suggested that antibiotic resistance may result in decreased fitness in the bacteria that harbor it. Observational studies have supported this, but due to ethical and practical considerations, it is rare to have experimental control over antibiotic prescription rates. METHODS AND FINDINGS: We analyze data from a 54-month longitudinal trial that monitored pneumococcal drug resistance during and after biannual mass distribution of azithromycin for the elimination of the blinding eye disease, trachoma. Prescription of azithromycin and antibiotics that can create cross-resistance to it is rare in this part of the world. As a result, we were able to follow trends in resistance with minimal influence from unmeasured antibiotic use. Using these data, we fit a probabilistic disease transmission model that included two resistant strains, corresponding to the two dominant modes of resistance to macrolide antibiotics. We estimated the relative fitness of these two strains to be 0.86 (95% CI 0.80 to 0.90), and 0.88 (95% CI 0.82 to 0.93), relative to antibiotic-sensitive strains. We then used these estimates to predict that, within 5 years of the last antibiotic treatment, there would be a 95% chance of elimination of macrolide resistance by intra-species competition alone. CONCLUSIONS: Although it is quite possible that the fitness cost of macrolide resistance is sufficient to ensure its eventual elimination in the absence of antibiotic selection, this process takes time, and prevention is likely the best policy in the fight against resistance.