Illumination by short-wavelength light inside the blind spot decreases light detectability.

Although the optic disk corresponding to the blind spot contains no classical photoreceptors, it contains photopigment melanopsin. To clarify whether melanopsin is involved in light detection, we conducted detection tasks for light stimuli presented in the normal visual field, with and without another illumination inside the blind spot. We found that a blue blind-spot illumination decreased the light detectability on a dark background. This effect was replicable when it was determined immediately after the blind-spot illumination was turned off, suggesting the contribution of a sluggish system rather than scattering. Moreover, the aforementioned effect was not observed when the blind-spot illumination was in red, indicating wavelength specificity in favor of melanopsin's sensitivity profile. These findings suggest that melanopsin is activated by the blind-spot illumination and thereby interferes with light detection near the absolute threshold. Light detection originating from conventional photoreceptors is modulated by melanopsin-based computation presumably estimating a baseline noise level.

Implantation of asymmetrical corneal intrastromal rings: A case series.

This case series reports eight eyes with keratoconus treated with laser implantation of one or two segments of progressive thickness corneal intrastromal ring (PT-ICRS). In this case series, it was evident that the insertion of PT-ICRS induces more pronounced corneal flattening at the thickest point, causing a reduction in distortion (coma) and lower astigmatism, resulting in a remarkable improvement in vision. Compared to the implementation of traditional intrastromal rings, the PT-ICRS variant showed superior results despite the small sample size. However, the same degree of asymmetry enhancement was not observed in cases in which a 330° PT-ICRS was implanted, despite the improvement in visual results when replacing a 320° traditional ring with a 330° PT-ICRS. These conclusions are limited as this is a case series with few cases.

Histopathology of the Tongue in a Hamster Model of COVID-19.

Objective: With altered sense of taste being a common symptom of coronavirus disease 2019 (COVID-19), our objective was to investigate the presence and distribution of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) within the tongue over the course of infection. Methods: Golden Syrian hamsters were inoculated intranasally with SARS-CoV-2 and tongues were collected at 2, 3, 5, 8, 17, 21, 35, and 42 days post-infection (dpi) for analysis. In order to test for gross changes in the tongue, the papillae of the tongue were counted. Paraffin-embedded thin sections of the tongues were labeled for the presence of SARS-CoV-2 antigen. Results: There was no difference in fungiform or filiform papillae density throughout the course of infection. SARS-CoV-2 antigen was observed in the circumvallate papillae taste buds (3-35 dpi) and autonomic ganglia (5-35 dpi), as well as in the serous and mucous salivary glands of the posterior tongue (2-42 dpi). Conclusion: The presence and distribution of SARS-CoV-2 suggest that the virus could cause taste disturbance by infecting the circumvallate taste buds. This effect could be exacerbated by a diminished secretion of saliva caused by infection of the serous salivary glands and the autonomic ganglia which innervate them.

Mitochondrial DNA mutations can influence the post-implantation development of human mosaic embryos.

Introduction: Several healthy euploid births have been reported following the transfer of mosaic embryos, including both euploid and aneuploid blastomeres. This has been attributed to a reduced number of aneuploid cells, as previously reported in mice, but remains poorly explored in humans. We hypothesized that mitochondrial function, one of the most critical factors for embryonic development, can influence human post-implantation embryonic development, including a decrease of aneuploid cells in mosaic embryos. Methods: To clarify the role of mitochondrial function, we biopsied multiple parts of each human embryo and observed the remaining embryos under in vitro culture as a model of post-implantation development (n = 27 embryos). Karyotyping, whole mitochondrial DNA (mtDNA) sequencing, and mtDNA copy number assays were performed on all pre- and post-culture samples. Results: The ratio of euploid embryos was significantly enhanced during in vitro culture, whereas the ratio of mosaic embryos was significantly reduced. Furthermore, post-culture euploid and culturable embryos had significantly few mtDNA mutations, although mtDNA copy numbers did not differ. Discussion: Our results indicate that aneuploid cells decrease in human embryos post-implantation, and mtDNA mutations might induce low mitochondrial function and influence the development of post-implantation embryos with not only aneuploidy but also euploidy. Analyzing the whole mtDNA mutation number may be a novel method for selecting a better mosaic embryo for transfer.

Ablação personalizada guiada por frente de onda após complicação na dissecção lamelar de FemtoLasik / Personalized wavefront-guided ablation after complication in FemtoLasik lamella dissection

RESUMO O FemtoLasik é uma das técnicas mais empregadas em cirurgia refrativa, por seus bons resultados refracionais, sua previsibilidade, sua reprodutibilidade e sua segurança. Tem alto grau de satisfação, com rápida recuperação visual. Apesar de as taxas de complicações do FemtoLasik serem pequenas, intercorrências podem existir. O objetivo deste trabalho foi relatar um caso de uma complicação na dissecção da lamela por Lasik com laser de femtossegundo com consequente rasgadura da lamela, sendo aplicado Excimer Laser com mitomicina C 0,02%. O retratamento foi realizado com ablação de superfície (ceratectomia fotorrefrativa) guiada por frente de onda, evoluindo com boa qualidade visual final.

ABSTRACT Femtolasik is one of the most used techniques in refractive surgery due to good refractive results, predictability, reproducibility, and safety, achieving excellent results and a high degree of satisfaction. Although the complication rates are small, it is worth noting that there may be intercurrences. The objective of this work is to report a case of complication in the dissection of the lamella of laser in situ keratomileusis (Lasik) with Femtosecond laser, and subsequent lamella tear. Excimer Laser was applied with mitomycin 0.02% and re-approached with wavefront guided surgery, evolving with good final visual quality.

Manifestações clínicas de ceratite ulcerativa periférica com ceratite neurotrófica: desafio terapêutico / Clinical manifestations of peripheral ulcerative keratitis together with neurotrophic keratitis: therapeutic challenge

RESUMO A ceratite ulcerativa periférica é uma infiltração corneana imunomediana associada a doenças autoimunes e inflamatórias sistêmicas. Comumente associada à artrite reumatoide, ela também pode estar associada a outras doenças reumatológicas, inflamatórias e doenças infecciosas. A ceratite ulcerativa periférica é geralmente unilateral e periférica, devido à proximidade com a vasculatura conjuntival. Há tipicamente um defeito epitelial sobrejacente ao infiltrado e afinamento do estromal associado. O objetivo deste relato de caso foi abordar uma das possíveis etiologias de ceratite ulcerativa periférica associada a quadro de ceratite neurotrófica por herpes simplex, apresentar sua apresentação clínica aguda e alertar sobre as implicações do tratamento.

ABSTRACT Peripheral ulcerative keratitis (PUK) is an immune-mediated corneal infiltration associated with autoimmune diseases and systemic inflammation. Commonly associated with rheumatoid arthritis, it may also be associated with other rheumatologic, inflammatory, and infectious diseases. PUK is usually unilateral and peripheral, due to its proximity to the conjunctival vasculature. There is usually an epithelial defect overlying the infiltrate and the associated stromal thinning. The objective of this case report is to address one of the possible etiologies of PUK associated with a picture of neurotrophic keratitis due to Herpes Simplex and its acute clinical presentation, and to warn about possible suggestions for treatment.

Fertility preservation immediately after therapeutic abortion results in multiple normal follicular growth with the absence of mature oocytes due to early luteinization: a case report and literature review.

Cancer therapy has priority over fertility preservation. The time available for fertility preservation in patients with cancer is often very limited and depends on the condition of the underlying disease. This case report presents the results of two rounds of controlled ovarian stimulations (COSs) performed after an induced abortion. The patient had mixed phenotype acute leukemia diagnosed during early pregnancy and underwent a surgical abortion, followed by ovarian stimulation using urinary follicle-stimulating hormone (uFSH) and gonadotropin-releasing hormone (GnRH) agonists. Oocyte retrieval was subsequently performed for oocyte cryopreservation. Despite good hormonal and ultrasonic follicular growth, no oocytes were obtained. During a second COS performed at a low human chorionic gonadotropin (hCG) level (less than 100 IU/L), several mature oocytes were obtained, suggesting that higher hCG levels during COS induce the absence of mature oocytes during normal follicular growth. It is recommended to start COS post-abortion after confirming a low hCG level while considering the timing of cancer treatment.

Invisible light inside the natural blind spot alters brightness at a remote location.

The natural blind spot in the visual field has been known as a large oval region that cannot receive any optical input because it corresponds to the retinal optic disk containing no rod/cone-photoreceptors. Recently, stimulation inside the blind spot was found to enhance, but not trigger, the pupillary light reflex. However, it is unknown whether blind-spot stimulation also affects visual perception. We addressed this question using psychophysical brightness-matching experiments. We found that a test stimulus outside the blind spot was judged as darker when it was accompanied by a consciously unexperienced blue oval inside the blind spot; moreover, the pupillary light reflex was enhanced. These findings suggested that a photo-sensitive mechanism inside the optic disk, presumably involving the photopigment melanopsin, contributes to our image-forming vision and provides a 'reference' for calibrating the perceived brightness of visual objects.