The pre-launch on-ground characterization of Ma_MISS spectrometer for ExoMars-Rosalind Franklin Rover mission. II. Radiometric calibration

The Ma_MISS miniaturized spectrometer is integrated within the Drilling System of the ExoMars Rosalind Franklin Rover for Mars exploration. Here we focus on the on ground calibration campaign to obtain radiometric and linearity calibrations of the Ma_MISS instrument, while the first paper dealt with the spectral calibration [De Angelis et al., Rev. Sci. Instrum. 93, 123704 (2022)]. The experimental setup used to carry out radiometric calibration is described, as are the methods used for data processing and key parameter retrieval. In particular, the Spectrometer Transfer Function (Responsivity), Signal-to-Noise Ratio, and detector linearity are determined. In a third paper [De Sanctis et al., Planet. Sci. J. 3, 142 (2022)], validation of the Ma_MISS calibration results through spectral measurements performed on rock and synthetic targets during the radiometric calibration campaign is described.

A Prospective Randomized Study Comparing 27-Gauge Vitrectomy to 23-Gauge Vitrectomy for Epiretinal Membranes and Full-Thickness Macular Holes

Purpose

To compare the surgical and clinical outcomes of 27-gauge vitrectomy and 23-gauge vitrectomy.

Methods

We conducted a single-center, prospective, randomized study. Fifty-three patients affected by vitreoretinal interface disorders (epiretinal membranes and macular holes) were randomly scheduled to undergo 27-gauge (28 patients) or 23-gauge (25 patients) pars plana vitrectomy. The presence of any potential factor of increased baseline inflammation or eye anatomy influencing the surgery was criteria for exclusion. The time of surgery, postoperative intraocular pressure (IOP), state of sclerotomy wounds, rate of complications, postoperative pain, and indicators of inflammation were studied. We also introduced a new parameter to compare intraocular inflammation after surgery, given by the change in the number of intraretinal hyperreflective foci (HRF).

Results

The 27-gauge vitrectomy was 1.28 min longer than 23-gauge vitrectomy (P < 0.05). The day after surgery, the mean IOP value was significantly higher in the 27-gauge group (16.12 mmHg versus 13.04 mmHg in the 23-gauge group,P < 0.05), but this difference disappeared in successive follow-ups and the sclerotomy wounds closed after 2 weeks in the both groups. The rate of postoperative hypotony did not significantly differ in the two groups (10.71% in the 27-gauge group and 8% in the 23-gauge group the day after the surgery,P = 0.94). Less postoperative eye redness was seen in 27-gauge eyes (value 1 on the scale) compared to 23-gauge (value 2 on the scale) (P < 0.05), but there was no significant difference in intraocular inflammation (cells, Tyndall, and number of HRF,P > 0.05 for all).

Conclusions

The 27-gauge vitrectomy may have better outcomes in terms of IOP maintenance and cause less redness after the surgery but with a slightly prolonged surgery time and no other differences under other parameters (inflammation, rate of complications, postoperative pain, visual gain, and closure of the sclerotomy wounds).

Constraining the Rosalind Franklin Rover/Ma_MISS Instrument Capability in the Detection of Organics

The Mars Multispectral Imager for Subsurface Studies (Ma_MISS) instrument is a miniaturized visible and near-infrared spectrometer that is integrated into the drilling system of the ESA Rosalind Franklin rover, which is devoted to subsurface exploration on Mars. Ma_MISS will acquire spectral data on the Martian subsurface from excavated borehole walls. The spectral data collected by Ma_MISS on unexposed rocks will be crucial for determination of the composition of subsurface rocks and optical and physical properties of materials (i.e., grain size). Ma_MISS will further contribute to a reconstruction of the stratigraphic column and acquire data on subsurface geological processes. Ma_MISS data may also inform with regard to the presence of potential biomarkers in the subsurface, given the presence of organic matter that may affect some spectral parameters. In this framework, we performed a wide range of measurements using the laboratory model of the Ma_MISS to investigate mineral/organic mixtures in different proportions. We prepared mixtures by combining kaolinite and nontronite with glycine, asphaltite, polyoxymethylene, and benzoic acid. These organic compounds show different spectral characteristics in the visible and near-infrared; therefore their presence can be detected by the Ma_MISS instrument. Our results indicate that the Ma_MISS instrument can detect organic material down to abundances of around 1 wt %. In particular, the data collected on low-concentration mixtures show that, by analyzing sediments with a grain size smaller than the Ma_MISS spatial resolution, the instrument can still discern those points where organic matter is present from points with exclusive mineral composition. The results also show that a collection of multiple contiguous measurements on a hypothetical borehole wall could help indicate the presence of organic matter in clay-rich soils if present.

The pre-launch on-ground characterization of Mars Multispectral Imager for Subsurface Studies (Ma_MISS) spectrometer for ExoMars rover mission: Spectral calibration

The Ma_MISS spectrometer is integrated within the drilling system of the Rosalind Franklin ExoMars rover. This paper reports the on-ground calibration campaign performed on the spectrometer. Here, we focus on the spectral calibration of the instrument. The experimental setup used to carry out calibration is described, and the methods used for data processing and key parameters retrieval are explained. In particular, the spectral parameters such as (i) pixel central wavelengths, (ii) spectral response function, (iii) spectral resolution, (iv) sampling, and (v) range are determined. In a follow-up paper, the linearity and radiometric calibrations are described, while in De Sanctis et al. [Planet. Sci. J. 3, 142 (2022)], the validation of spectral measurements performed on synthetic and natural rock targets is presented.

An update on the ophthalmic features in hereditary haemorrhagic telangiectasia (Rendu-Osler-Weber syndrome)

Hereditary haemorrhagic telangiectasia (HHT) or Osler-Rendu-Weber syndrome is a rare autosomal dominant disease, characterised by systemic angiodysplasia. Dysfunction of the signalling pathway of β transforming growth factor is the main cause of HHT principally owing to mutations of the genes encoding for endoglin (ENG) and activin A receptor type II-like 1 (ACVRL1). Clinical manifestations can range from mucocutaneous telangiectasia to organ arterio-venous malformations and recurrent epistaxis. The early clinical manifestations may sometimes be subtle, and diagnosis may be delayed. The main ophthalmic manifestations historically reported in HHT are haemorrhagic epiphora, and conjunctival telangiectasia present in 45-65% of cases, however, imaging with wide-field fluorescein angiography has recently shown peripheral retinal telangiectasia in 83% of patients. Optimal management of HHT requires both understanding of the clinical presentations and detection of early signs of disease. Advances in imaging methods in ophthalmology such as wide-field fluorescein angiography, spectral domain optical coherence tomography, and near infrared reflectance promise further insight into the ophthalmic signs of HHT towards improved diagnosis and early management of possible severe complications.

Unusual case of enlarged choroidal vessels in neurofibromatosis type 1 observed with near-infrared reflectance and spectral domain optical coherence tomography

The cardinal diagnostic signs of neurofibromatosis type 1 (NF1) are Lisch nodules of the iris and optic pathway gliomas. Retinal mi-crovascular alterations have been described but with uncertain signi-ficance. Choroidal nodules, detectable with near-infrared reflectance (NIR) imaging, are present in most cases and have been proposed as a new diagnostic criterion. Recently, a study reported the presence of unusual dilated choroidal vessels, visible through NIR examination. We report a case of a 65-year-old patient with NF1. Best-corrected visual acuity was 20/20 with a refractive error of +2.75 diopters in both eyes. Anterior segment examination revealed Lisch nodules in both eyes. At NIR imaging the patient presented typical choroidal alterations in both eyes. No retinal vessel anomalies were detected. The patient presented enlarged choroidal vessels in the left eye, first detected by NIR and then analyzed through enhanced depth imaging spectral domain optical coherence tomography (EDI-SDOCT). These vessels extended from the choroidal-scleral junction to the outer border of the retinal pigment epithelium/Bruch's layer. The choriocapillaris layer was absent above the dilated vessels. The presence of enlarged choroidal vessels may be considered as a novel distinctive ophthalmologic aspect of NF1, but further studies are necessary.

Visual Performances of a New Extended Depth-of-Focus Intraocular Lens with a Refractive Design: A Prospective Study After Bilateral Implantation

Purpose

The aim of the present study was to evaluate the visual outcome of a new extended depth-of-focus (EDOF) intraocular lens (IOL) after bilateral implantation. A qualitative and quantitative analysis was performed and data were compared with those given by other studies regarding multifocal IOLs, which have the same purpose of giving spectacle independence to the patients.

Methods

The study enrolled 40 eyes of 20 patients who underwent cataract surgery with bilateral implantation of an EDOF IOL (Evolve Soleko, Rome, Italy). The mean age was 74.5±9 years (range 59-83ys). Refractive outcomes and contrast sensitivity were evaluated preoperatively and at 6-month follow-up. We also examined reading speed, glare, halos, difficulties in the night driving, the requirement for spectacles, and overall satisfaction with vision. Two questionnaires were administered for this purpose.

Results

At 6 months, the percentage of eyes within ±0.50 diopters (D) from emmetropia was 82.5%. Of all patients, 90% were satisfied with their vision. The percentage of spectacle-free for near and distance vision patients was 70% and 95%, respectively. A postoperative binocular uncorrected 60cm intermediate visual acuity (UI60VA) of 0.2 logMAR or better was achieved in 92% of patients. Contrast sensitivity significantly improved postoperatively (p<0.001) and mean reading speed was good.

Conclusion

This new EDOF IOL seems to provide an effective alternative to patients who desire a spectacle-free lifestyle postoperatively. These lenses can supply a satisfactory distance, intermediate and near vision, and retain good contrast sensitivity, with most patients reporting excellent satisfaction.

Current concepts on diffuse choroidal hemangioma in Sturge Weber syndrome

Background: Diffuse choroidal hemangioma (DCH) is a benign vascular tumor that is characteristically found in the Sturge-Weber syndrome (SWS). Recent genetic discoveries demonstrate that DCH occurs sporadically from an activating mutation in GNAQ at codon R183. Mutations in GNAQ or GNA11 result in dysregulation of the mitogen-activated protein kinase, which influences gene transcription and results in cellular proliferation. DCH may not always be readily detected on routine ophthalmological examination, consequently diagnosis and multidisciplinary referral are often delayed.Purpose: A literature search was performed through April 2020 without a lower date limit. This review will summarize the pathogenesis, diagnosis and management of DCH.Discussion: Multimodal imaging facilitates early detection of the condition. In particular, enhanced depth imaging spectral domain optical coherence tomography enables non-invasive, high-resolution visualization of the choroid to even detect mild choroidal thickening. Management of symptomatic DCH is generally difficult and results in poor visual outcome, thus, treatment is generally unwarranted, unless the hemangioma complicated by serous retinal detachment. The main treatment method is radiation therapy with external beam radiation therapy, proton beam therapy, plaque brachytherapy, and gamma knife surgery where low doses of radiation entail fewer complications. One method of alternative management is with photodynamic therapy that, although less invasive with a lower rate of complications, is not always feasible or effective in cases with extensive exudative retinal detachment.Conclusions: Multimodal ophthalmological imaging facilitates diagnosis of DCH and lifelong surveillance is essential in patients.

Effects of Scleral Contact Lenses for Keratoconus Management on Visual Quality and Intraocular Pressure

Purpose

To evaluate the visual acuity level achieved by scleral contact lens (CL) fitting in patients affected by keratoconus and to evaluate possible intraocular pressure (IOP) changes during the scleral CL wear using a transpalpebral tonometer.

Methods

In a prospective case series a comparison was made between visual acuity obtained with glasses, RGP and 16.8mm diameter scleral CL in 30 consecutive patients affected by keratoconus. IOP was tested during scleral CL wear by transpalpebral Diaton Tonometer (DT) and also by Goldmann Applanation Tonometer (GAT) before and after scleral CL wear.

Results

The mean logMAR visual acuity improved from 0.2±0.25SD with glasses and 0.1±0.02SD with RGP, to −0.002±0.041SD when using the scleral CL (p<0.05). The mean IOP value before scleral CL wear was 12.93mmHg±2.20SD when measured with GAT and 7.85mmHg±2.27SD when measured with DT. During scleral CL wear, IOP was assessed through DT, with a mean value of 8.86mmHg±2.36SD; values were stable after 8 hours of scleral CL use. Immediately after scleral CL removal, the mean IOP measured with GAT was 12.85mmHg ±2.40SD and the mean IOP measured with DT was 7.66mmHg±1.88SD. Therefore, during scleral CL wear, it was evidenced a small but statistically significant increase of the mean IOP value (1.01mmHg; p<0.01), with a reversion to values prior to application when scleral CL was removed.

Conclusion

Scleral CLs remarkably improved visual acuity in keratoconus patients when compared to glasses or RGP contact lenses. Even if it was evidenced a small increase of the mean IOP value during their wear, it may not be significant in otherwise healthy eyes. Statistical analysis demonstrated good agreement between GAT and DT but their numerical values presented a constant gap, that should be taken into account when there is a need to relate the DT values to the reference ones.

Long-term follow-up of adult patient with neurofibromatosis type 1 with retinal astrocytic hamartoma using spectral-domain optical coherence tomography: a review of the literature and a report of a case

Background: Retinal astrocytic hamartoma (RAH) is a tumor that can be sporadic or in the context of tuberous sclerosis complex (TSC) and has been reported to be associated with neurofibromatosis type 1 (NF1) in a few cases.Patient and methods: A 65-year-old male patient with NF1 was referred for ophthalmological evaluation. Comprehensive examination, near-infrared reflectance (NIR), spectral-domain optical coherence tomography (SDOCT), fluorescein angiography (FFA), and indocyanine green angiography (ICGA) were carried out. The follow-up of the patient was at 4 and 7 years.Results: Best-corrected visual acuity (BCVA) was 20/20 in both eyes. Anterior segment examination revealed bilateral Lisch nodules. Fundus examination was unremarkable but at NIR and SDOCT the patient presented choroidal hamartoma, microvascular retinal alterations, and enlarged choroidal vessels in both eyes. NIR also revealed an unusual area of peripapillary hyporeflectivity in the right eye. On SDOCT, this corresponded to an elevated peripapillary mass characterized by intralesional optically empty cavities in the retinal nerve fiber layer (RNFL) and ganglion cell layer-inner plexiform layer (GCL-IPL), diagnosed as a RAH. Four years later, BCVA was 20/25 with a retinal schisis departing from the lesion to the macula. At 7 years, BCVA was stable at 20/25, the lesion was smaller, and there was a slight reduction of the schisis.Conclusion: RAH is a rare finding in NF1 and the translucent type has not been previously reported. RAH in NF1 has a peripapillary location and demonstrates clinically unpredictable behavior; thus, close monitoring with multimodal imaging is advisable.

Unusual Case of Indolent Choroidal Alterations Mimicking Neurofibromatosis Type 1

Indolent, non-progressive choroidal alterations can be strongly suggestive of neurofibromatosis type 1 (NF1) but are also rarely of unknown aetiology. A 63-year-old man presented for a routine examination. Comprehensive ophthalmological examination and retinal imaging was performed. Visual acuity was 20/20. The anterior segment and fundus were unremarkable. Near-infrared reflectance (NIR) with spectral-domain optical coherence tomography showed unilateral hyperreflective areas in the left posterior pole, corresponding to choroidal nodules on enhanced depth imaging and hypofluorescent areas on indocyanine green angiography. Dermatological evaluation and genetic testing for NF1 were negative. Chest computed tomography, liver function, HLA-A29, and angiotensin-converting enzyme level were negative. The patient has remained in good health and the choroidal alterations have remained non-progressive for 3 years. Choroidal alterations observed with NIR could be a manifestation of somatic mosaicism or a variation of a new unclassified correlated condition that may be better elucidated in the future, given the use of novel imaging techniques that are currently available in ophthalmology.

Bilateral diffuse choroidal hemangioma in Sturge Weber syndrome: A case report highlighting the role of multimodal imaging and a brief review of the literature

Purpose

To present a patient with bilateral choroidal hemangioma in Sturge-Weber syndrome (SWS) and highlight multimodal imaging techniques for early detection and management of ocular alterations.

Methods

A 37-year-old woman with diagnosis of SWS presented to our unit. The patient had been treated with pulsed dye laser for bilateral nevus flammeus and had right leptomeningeal angiomatosis. She had glaucoma, but ultrasound biomicroscopy did not show anterior chamber or ciliary body alterations.

Results

Enhanced depth imaging (EDI) spectral domain optical coherence tomography (SD-OCT) showed bilateral diffuse choroidal hemangiomas in both eyes with choroidal thickness above 1000 μm. B-scan ultrasound examination showed diffuse choroidal hemangioma in both eyes, with a choroidal thickness of 1.53 mm and 1.94 mm in the right and left eye (RE, LE), respectively. Peripapillary retinal nerve fiber evaluation showed thinning of the retinal nerve fiber layer in both eyes.

Conclusions

This report highlights multimodal imaging techniques for the critical assessment of patients with SWS, especially in rare cases with bilateral choroidal hemangioma of the choroid. Novel imaging modalities enable optimal management and follow-up of rare conditions, and our case adds further evidence to the existing literature.

Design, development, and testing of an environmental P-T cell for infrared spectroscopy measurements

Water absorption bands due to superficially adsorbed molecules often dominate the near-infrared spectra of particulate minerals and rocks, when measured in the laboratory in the reflectance mode. In order to remove this, the spectral effect is thus necessary to acquire spectra of samples in vacuum and at higher temperatures. With the aim to accomplish this task, we developed an environmental cell to perform infrared spectroscopic measurements at controlled pressure-temperature conditions. Currently the cell allows one to measure reflectance spectra in the temperature range from room values up to 300 °C (573 K), in the pressure range of 10³-10^-6 mbar. The acquisition of spectra continuously in two distinct phases, namely, during a preliminary pumping stage (at room T) and subsequently during a heating stage (in vacuum), permits to highlight and characterize separately the effect of pressure and temperature on infrared spectra.

Localized aliphatic organic material on the surface of Ceres

Organic compounds occur in some chondritic meteorites, and their signatures on solar system bodies have been sought for decades. Spectral signatures of organics have not been unambiguously identified on the surfaces of asteroids, whereas they have been detected on cometary nuclei. Data returned by the Visible and InfraRed Mapping Spectrometer on board the Dawn spacecraft show a clear detection of an organic absorption feature at 3.4 micrometers on dwarf planet Ceres. This signature is characteristic of aliphatic organic matter and is mainly localized on a broad region of ~1000 square kilometers close to the ~50-kilometer Ernutet crater. The combined presence on Ceres of ammonia-bearing hydrated minerals, water ice, carbonates, salts, and organic material indicates a very complex chemical environment, suggesting favorable environments to prebiotic chemistry.

The diurnal cycle of water ice on comet 67P/Churyumov-Gerasimenko

Observations of cometary nuclei have revealed a very limited amount of surface water ice, which is insufficient to explain the observed water outgassing. This was clearly demonstrated on comet 9P/Tempel 1, where the dust jets (driven by volatiles) were only partially correlated with the exposed ice regions. The observations of 67P/Churyumov-Gerasimenko have revealed that activity has a diurnal variation in intensity arising from changing insolation conditions. It was previously concluded that water vapour was generated in ice-rich subsurface layers with a transport mechanism linked to solar illumination, but that has not hitherto been observed. Periodic condensations of water vapour very close to, or on, the surface were suggested to explain short-lived outbursts seen near sunrise on comet 9P/Tempel 1. Here we report observations of water ice on the surface of comet 67P/Churyumov-Gerasimenko, appearing and disappearing in a cyclic pattern that follows local illumination conditions, providing a source of localized activity. This water cycle appears to be an important process in the evolution of the comet, leading to cyclical modification of the relative abundance of water ice on its surface.

[Chronic intestinal inflammatory diseases]

In the last years the research on the etiopathogenesis of the inflammatory bowel disease (IBD) is focused around immunological aspects. Many authors consider that the intestinal inflammation is due to an inappropriate immunological response to normally present antigens in the gut. Two aspects must to be considered between IBD: Crohn's disease and ulcerative colitis. IBD's diagnosis is based on the symptomatology, (cramps, liquid feces with mucus and blood, anorexia and weight loss), hemato-clinical tests (ESR, PCR, blood platelet, mucoprotein, sideremia) and radiological tests (tenuis Rx, abdominal echography, fibro endoscophy and scintigraphy). Principal aim of the therapy is the clinical remission. Following the remission starts a maintenance protocol. Parenteral nutrition is used in paediatric and adolescent age. Diets have been used to provide a convenient nutritious contribution with growth improvement and partial remission of activity index of the disease. Pharmacology therapy represents a valid instrument to obtain the remission. Colectomy is performed on unsuccessful medical therapy. Early studies on IBD's pathogenesis bring to the use of biological therapies that show beneficial effects on the disease.

Value of antigliadin antibodies (AGA) in latent coeliac disease (CD)

BACKGROUND

The term latent coeliac disease (CD) is applied to patients who were previously shown to have a normal jejunal mucosa on a free diet. The aim of this study was to determine whether a high AGA value in the serum of patients with coeliac symptoms can also be regarded by itself, without typical mucosal atrophy, as a marker of latent CD, as some authors suggest in relatives of celiac patients.

METHODS

We observed 31 patients with suspected CD and pathological values of serum IgA ang IgG AGA. In all we performed intestinal biopsy, assayed antiendomisium antibodies (AEA) in serum, AGA IgA, IgG, and IgM in duodenal jejunal fluid and in some of the lymphocytcs CD3+ gamma/delta+ in the lamina propria of the intestinal mucosa.

RESULTS

In this study only pathological values of serum AGA without mucosa atrophy don't seem to be markers of latent CD, but an aspecific allergic response.

CONCLUSIONS

As shown by other authors serum AEA, intestinal fluid AGA IgM and lamina propria lymphocytes CD3+ gamma/delta+ seem markers of latent CD.

[Gastroesophageal reflux in children]

Gastroesophageal reflux (GER) is the return of gastric content from stomach to esophagus. The above phenomenon takes place for sphincter insufficiency of lower esophagus. RGE causes are various. RGE disease must be suspected when a children or an infant shows symptoms such as regurgitation and/or after lunch vomit, poor weight growth, anorexia, pyrosis, etc. In the last years dietetic and pharmacologic therapy have brought an improvement and/or a remission of the GER disease.

[Reappearance of alopecia areata in a coeliac patient during an unintentional challenge with gluten]

A patient with coeliac disease presenting alopecia areas as the only symptom is described. Alopecia disappeared completely after a few months of strict gluten free diet and reappeared after an unintentional prolonged introduction of gluten. After a severe gluten free diet, a new and persistent hair growth in the alopecia areas was observed. The possibility a direct relationship in some cases, between coeliac disease and alopecia areata is confirmed.

[Celiac disease and autoimmunity: state of the art]

Coeliac disease is probably an immunologic disease of the small intestine which is caused by a gluten intake as promoting agent in genetically predisposed persons. Many authors described this autoimmune assumption: most of coeliac patients carry the HLA type, HLA-DQ (alpha 1 x 0501, beta 1 x 0201) etherodimer; it was found a correlation between disease specific antibodies antigliadin (AGA), antireticulin (ARA) and antiendomysium (AEA). Therefore an increase of autoantibodies and lymphocytes in the blood of coeliacs suggest the autoimmune nature of coeliac disease.