Changes In Accommodation Research Articles

Generalized Fatigue: Why Post-Polio Syndrome Should Be Included as A Differential Diagnosis

Dear Editor, Post-Polio Syndrome (PPS) is a neurological condition that manifests in the form of non-specific symptoms such as fatigue, sleep dysfunction, muscle and bone pains, at least 15 years after the initial infection with polio virus. Multiple mechanisms have been suggested to describe the pathogenesis of PPS, with some studies attributing it to accommodative changes in the muscle fibers, with replacement of type II fibers by type I fibers and muscle hypertrophy. It has also been postulated that the virus may persist unknowingly or be reactivated. Additionally, inflammatory and autoimmune causes have also been hypothesized.1 Among the symptoms, fatigue, muscle weakness with atrophy and motor dysfunction are the most common ones to be reported in PPS, associated with significant morbidity in patients. 2 Owing to the non availability of diagnostic tests for this condition, PPS remains a diagnosis of exclusion with factors such as a confirmation of previous polio infection and subsequent resolution characterized by neurologic stability for more than 15 years, abrupt onset of neurologic symptoms with persistence for one year, and exclusion of other possible attributable medical conditions established as essential parts of its diagnostic criteria. 3 The management of the condition is mainly based on physical therapy, and previous researches based on the use of drugs such as pyridostigmine, steroids, and IV immunoglobulins have shown limited efficacy in the improvement of the prognosis and condition of PPS patients.2 As of today, Pakistan remains among the three countries where the transmission of polio virus is prevalent, with the majority of outcomes in the past twenty years attributed to areas in the northern transmission zone bordering eastern Afghanistan, such as Khyber Pakhtunkhwa and Federally Administered Tribal Areas, and those in the southern transmission zone including southern Punjab, northern Sindh and Karachi.4 According to the Pakistan Polio Eradication Programme, 354 cases of polio virus have been reported in Pakistan from 2015-2024, with the highest number of infections occurring in Khyber Pakhtunkhwa. This is in contrast to the 20,000 cases reported in the early 1990s prior to immunization efforts.5 Statistically, 15-20 million people across the globe still suffer from the sequelae of infection with the virus.1 Additionally, it has been postulated that about 25 to 40 percent of such survivors of poliomyelitis will experience PPS at some point in their lifetime. ---Continue

High-resolution cyclic framework for the Songliao Basin in northeastern China, and its implications for sedimentation and organic matter enrichment

The study of fine-grained sedimentation has consistently concentrated on investigating the mechanisms and principles governing the enrichment of organic matter. However, the lack of unified stratigraphic framework has always existed as fine-grained sedimentation covers two distinct grain-size grades, namely, mud and silt, which has impeded the progress of subsequent production research. This study exemplified this issue by analyzing the first member of the Qingshankou Formation in the southern Songliao Basin. We established reconstructed gamma and density curves that mitigated filter noise interference, integrated high-resolution sequence results with astronomical cycle divisions, and created a high-frequency isochronous stratigraphic framework for clastic fine-grained sedimentation by leveraging the weak sensitivity of sandstone density curves and the robust stability in eccentricity cycle extraction. This approach addresses the inconsistencies in stratigraphic division methodologies and mismatched outcomes stemming from the use varying techniques to delineate mud and silt components within clastic fine-grained sedimentary sequences. Furthermore, it elucidates how tectonic-scale variations in sediment supply coupled with potential accommodation changes dictate macroscopic stacking patterns within strata, whereas climate fluctuations on orbital time scales govern sand-mud progradation degrees within these layers, culminating in periodic rhythmic characteristics characterized by vertical sand-mud interbedding. A model for stratigraphic development pertaining to lake delta systems constrained by a “synchronous heterotopy” paradigm is proposed for the southern Songliao Basin. The organic matter enrichment pattern aligns with its filling dynamics, indicating an “overfilling” type developmental pattern at lower strata levels where organic material predominantly originates from terrestrial plant debris external to the basin; this material accumulates primarily within silty zones along layers—with areas exhibiting heightened enrichment values slightly lagging behind short-eccentric maxima positions. In contrast, under an upper “balanced filling” type developmental framework, sources of organic matter are derived both internally and externally relative to the basin—exhibiting substantial heterogeneity—and regions marked by elevated organic matter concentrations are directly associated with locations identified as short-eccentric maxima.

Paleoenvironmental reconstruction of coal deposition during the Cretaceous-Paleogene transition in the Eastern Cordillera Basin, Colombian Andes

Stratal stacking patterns and factors influencing peat accumulation in coastal and continental settings represent a significant problem in studying coal-bearing sequences. To address this issue, this work focused on the Cretaceous-Paleogene Guaduas Formation on the Checua-Lenguazaque Syncline (CLS) coalfield in the Eastern Cordillera Basin (Colombian Andes). This study relies on geological survey, facies analysis, sequence stratigraphy, organic geochemistry, and coal petrography. Through these methods, depositional systems and sequences were characterized, and their relationship with coal composition was established. Sedimentary facies were categorized into four Facies Associations (FAs): lagoon, tidal flat, delta plain, and mixed fluvial system. Five T-R sequences (S1 to S5, in ascending order) were identified. S1 consists of lagoon and tidal sandstone, mudstone, and coal. S2-S4 comprise tidal, deltaic, and fluvial deposits. S5 is composed mainly of deltaic and fluvial facies. Thick coal seams (> 0.7 m) were concentrated in the regressive system tracts of S1 and S3, while the transgressive coals were deposited in S2-S3 and are associated with tidal environments. The organic petrography showed enrichment in vitrinite (30.00–85.20 %), while liptinite (0.00–16.60 %) and inertinite (4.60–34.40 %) varied according to depth and paleoenvironments. CLS coalfield displays an environmental evolution from shallow marine and lagoon deposits to deltaic and fluvial environments. Minor sea-level fluctuations, changes in accommodation, siliciclastic influx, and plant community distinguish this sedimentary succession. The deposition of the Guaduas Formation is characterized by a prograding pattern with dominant shallowing-upward cycles in a high accommodation setting. The organic matter accumulated under limno-telmatic to telmatic conditions in mesotrophic to ombrotrophic environments with nutrients derived mainly from rainfall. The paleoclimate for the Guaduas Formation indicates wet and hot conditions for flora expansion. This investigation determined paleoenvironments of the Maastrichtian-Paleocene coastal to fluvial successions within the tropical latitudes, indicating a strong relationship between depositional systems, sequence stratigraphy, paleoclimate, and coal composition.

Sediment supply variation control on Lower Eocene delta sequences (Tremp Basin, Spain)

Sediment supply variations are often overlooked when interpreting depositional sequences, with most studies instead emphasizing changes in accommodation space. Here, we investigated a temporally well-constrained shallow-marine succession in the Tremp Basin to test the control of sediment supply variations on the development of deltaic sequences during the early Eocene. We analyzed the paleoenvironmental record (sedimentary facies and δ13Corg values) of the Morillo Limestone and the Castigaleu Formation (52.2−50.6 Ma). The first progradation of the deltaic system is marked by the abrupt appearance of thick delta-front sandstones and associated with the first negative carbon isotopic excursions (CIEs) in the measured δ13Corg record. Subsequent phases of progradation align with subsequent negative CIEs. Conversely, positive CIEs correspond to finer-grained, more-distal prodelta deposits. A series of hyperthermal events occurred during the deposition, globally identified as negative CIEs on δ13Ccarb reference curves, which we tentatively correlate with our δ13Corg data. We therefore suggest that during deposition of this Lower Eocene shallow-marine succession, the primary trigger behind sequence generation was the high-frequency climate-induced variation in sediment supply, specifically the hyperthermal events, rather than changes in accommodation. This linkage underscores the complex interactions between climate dynamics and sedimentary responses that shape the stratigraphic architecture of shallow-marine settings.

Outcomes for centenarian patients admitted with orthopaedic trauma

IntroductionThe United Kingdom (UK) and world's population is aging with patients living longer, often with many co-morbidities. It is expected that patients of extreme old age would have poor outcomes following trauma; however, this assumption is not clearly evidenced. This study aims to present the outcomes of patients aged 100 or older admitted to a single hospital trust following admission for orthopaedic trauma. MethodA prospective cohort of patients aged 100 years and over admitted to the trauma and orthopaedic departments of two hospitals within the same trust between 2008 and 2022 was reviewed. Age was median 101 years (100–106 years). Outcome measures were length of stay, survival, complications and change in accommodation. Results80 patients met the inclusion criteria (71female, 9 male). Mean age at discharge was 102.5 years with survival mean 4.2 years. 2 patients with peri-prosthetic fracture survived a further 5 years. Mean length of stay was 17 days. 57 patients returned to their original place of residence. 72 patients (90 %) survived the acute hospital admission. ConclusionSurvival rates for patients aged over 100 years were high and most returned to the previous place of residence. This study supports the surgical management of trauma and helps inform patients and families expectations for mortality risk.

Changes in Visual Parameters during Paramenstruum in a Rural Population of Eastern India: A Pilot Study

Aim This study aims to analyze a set of symptoms of visual difficulties due to accommodative changes before and during the period of menstruation.  Methods This cross-sectional study includes 60 females of the rural population having an accommodative facility of 14 cycles/min with ±2.00D flippers. All subjects have undergone a comprehensive ocular examination which also includes investigation of different parameters of accommodation and convergence before and during menstruation. This Statistical analysis was done with the help of paired T test and the result was shown as significant if P< 0.05.  Results Pre-menstruation no accommodative changes were found. During menstruation, all the subjects were found with a significant change in NPA (OD, OS), AA (OD, OS), NRA, PRA, PFV (Break-Near) and AF (OU) during menstruation. 66.7% of subjects were found with symptoms of headache, backache, difficulty in reading and blurring of vision during menstruation. After prolong near work 16.7% of subjects were found with the blurring of near vision 16.7% were found with the blurring of distance vision.  Conclusion Accommodative insufficiency along with its associated symptoms may induce during the menstruation cycle. The clinician should consider accommodative changes during eye examination of an adult female.

Cretaceous cyclic peritidal carbonates of the Apulia Carbonate Platform (Apulia, southern Italy) in a hierarchical sequence‐stratigraphic perspective: A case study from the Murge area (the Giovinazzo sea‐cliff section)

AbstractCretaceous cyclic peritidal carbonates form the bulk of the Apulia Region in Italy and represent the vestiges of the Apulia Carbonate Platform. To show from a sequence stratigraphic perspective the architecture of peritidal carbonates, the 17 m thick Albian Giovinazzo sea‐cliff section was studied at a centimetre detail, aiming to: (i) describe cyclic facies organisation in beds and bedsets; (ii) reconstruct the relative sea‐level curve and its evolution over time; (iii) interpret the long‐term evolution of the accommodation space in terms of sequence stratigraphy. The hierarchical stacking pattern of facies in beds and bedsets reveals Milankovitch cyclicity. As a working hypothesis, elementary sequences are assumed to represent the precession cycle (ca 20 kyr) and small‐scale and medium‐scale sequences the short (ca 100 kyr) and long (ca 400 kyr) eccentricity cycles, respectively. Four different types of elementary sequences (condensed, catch‐down, catch‐up and give‐up) are recognised and interpreted in terms of relative sea‐level changes to reconstruct the relative sea‐level curve of the entire succession. The envelope of the reconstructed relative sea‐level curve is used to represent the long‐term accommodation change on the platform, which covers a time span of approximately 1.8 Myr. Most of this time was spent in subaerial exposure, as approximately 1.2 Myr was predicted to be condensed in a stratigraphic interval encompassing both the sequence‐boundary zone/falling stage deposits and the lowstand deposits. Moreover, it was interpreted that about two‐third of the total thickness of the succession was formed in only 280 kyr and consisted of both transgressive and maximum‐flooding deposits. The main implication of this study is that unconformities do not necessarily correspond to single surfaces but, rather, to very amalgamated intervals or unconformity zones. Moreover, based on biostratigraphic constraints, there is a correlation between the unconformity zone of the studied succession and the third‐order KAl4 sequence boundary of the Cretaceous eustatic cycle chart.

Three-dimensional geological modeling applied to multiscale heterogeneity of a reservoir analog: Paleocoastal deposits from the Rio Bonito formation, Paraná Basin

Coastal sandstones have high permoporosity and contain significant hydrocarbon reserves, although they present variable flow heterogeneities. The goal of this paper is to understand the distribution of potential reservoir-flow units in the Rio Bonito Formation (early Permian, Paraná Basin) and to investigate heterogeneities on multiscale. We use stratigraphic, sedimentological, 3D model, and petrological data to evaluate reservoir heterogeneities. System tracts were modeled by sectioning the entire succession into five zones. Eleven facies associations were modeled separately within each zone, using geostatistical analysis and different algorithms. The 3D model was validated by jackknife procedure, and the distribution of facies associations adequately represented both depositional and stratigraphic frameworks. The results are adequate in a curve of accommodation changes similar to previous proposal for the study area. Tidal sand bar facies association presents as elongated (parallel to depositional dip) to sheetlike geobodies according to amalgamation grade, while upper and middle shoreface one is mostly elongated (parallel to depositional strike) to sheetlike. Besides, fluvial channel facies association occurs mainly elongated parallel to depositional dip, forming multilateral and multistory geobodies. Modeled depositional geometries were distinguished along the succession, showing similarities to Rio Bonito Formation outcrops, recent environments, and other deposits around the world, such as estuarine strata from Oriente Basin and shoreface ones from Gulf of Mexico Basin. Using a detailed petrological analysis, eleven reservoir petrofacies were defined and classified into good-, medium-, and low-quality reservoirs or non-reservoirs. Tidal sand bar, upper-middle shoreface, and fluvial channel deposits were categorized as the main reservoir-flow units. This study provides predictive scenarios for heterogeneities in reservoirs and may be applied in petroleum fields.

The Effect of Ambient Illumination and Text Color on Visual Fatigue under Negative Polarity.

This study investigates the effects of ambient illumination and negatively polarized text color on visual fatigue, exploring the issue of visual fatigue when using visual display terminals in low-illumination environments. The research methodology utilizes an experimental design to collect data on changes in pupil accommodation and blink rate through an eye tracker. Participants completed a reading task while exposed to various text colors and ambient light conditions to evaluate visual fatigue and cognitive performance. The study's findings suggest that text color significantly affects visual fatigue, with red text causing the highest level of visual fatigue and yellow text causing the lowest level of visual fatigue. Improvements in ambient lighting reduce visual fatigue, but the degree of improvement varies depending on the text color. Additionally, cognitive performance is better when using yellow and white text but worse when using red text. Yellow text is the most effective choice for reducing visual fatigue under negative polarity. Increasing ambient lighting can also improve visual fatigue in low-illumination conditions. These findings will offer valuable guidance for designing visual terminal device interfaces, especially for low-illumination or night environments, to minimize visual fatigue and improve user experience.

Bayhead delta succession as a stratigraphic marker of sea‐level changes during the early to late Holocene – the Nakdong valley of south‐eastern Korea

ABSTRACTBayhead deltas form at the interface between fluvial and estuarine systems. As such, they are sensitive to processes operating in both the fluvial catchment and the marine realm, including past relative sea‐level changes. The Nakdong valley is a small and confined incised valley containing a bayhead delta that provides a record of fluvial sediment input and accommodation changes. Based on a facies analysis that included 833 sediment textures and 118 optically stimulated luminescence and radiocarbon ages within five cores up to 70 m long, this study reconstructed the development of a fully filled bayhead delta in response to relative sea‐level changes through the early to late Holocene. Sixteen facies are defined and grouped into eight facies associations: alluvial plain; fluvial channel and floodplain; oxidized fluvial channel; tidal flat; tidal bar; central basin and bayhead prodelta; bayhead delta front; and bayhead delta plain. The sequence stratigraphy of the Nakdong valley fill can be divided into three systems tracts: a lowstand systems tract, a transgressive systems tract and a highstand systems tract. Overall sedimentary analyses suggest six depositional stages corresponding to variations between sediment inputs and sea‐level rise of the developing bayhead delta in the Nakdong valley. The depositional model tracks relative sea‐level rise in the Nakdong valley after 12 ka during the early to late Holocene. These analyses on the Nakdong bayhead delta succession illustrate the balance between sediment inputs and periods of accelerating and decelerating relative sea‐level rise during the Holocene. The architecture of the valley fill also records two abrupt disequilibrium events from 9 to 8 ka and 5 to 3 ka, likely resulting from rapid sea‐level rise during the deglacial outburst flooding of the early Holocene and decreased sediment inputs during regional climatic changes associated with the middle Holocene, respectively.

Architecture and history of uranium-bearing Palaeocene–Eocene strata deposited on the eastern margin of the Peri-Tethys (Chu-Sarysu Basin, south Kazakhstan)

Deciphering the facies and architecture of alluvial successions provides invaluable insights into the interplay of tectonics, climate, eustasy, and autogenic processes affecting terrestrial sedimentary systems. The stratigraphic response of fluvial systems to variations in discharge and sediment-supply regimes is now well-understood and is tied to changes in climate, precipitation patterns, or sediment sources. The uraniferous Chu-Sarysu Basin in south Kazakhstan occupies the tectonically stable Turan Platform on the eastern margin of the Peri-Tethys, and the study of its Palaeocene–Eocene sedimentary fill offers an opportunity to unravel eustatic and climatic controls that drove the architecture of reservoirs hosting economically important deposits. The stratigraphic succession comprises two multistorey, laterally extensive, sheet-like sandstone bodies floored by prominent erosion surfaces and interpreted as the deposits of channel belts. These packages are interstratified with floodplain, coastal-wetland, and marine-embayment complexes reflecting major extra-channel belt avulsions and marginal-marine incursions on the low-gradient alluvial plain. The stratal architecture was controlled by changes in accommodation likely induced by well-documented sea-level changes in the Peri-Tethys during the Palaeogene, which permitted the development of a chronostratigraphic framework. Eustatic variations culminated in the widespread flooding of the Turan Platform in the middle Eocene, reflected by transgressive lags above a wave ravinement surface capping terrestrial and marginal-marine deposits. Marked changes in fluvial facies, floodplain styles, and inferred channel planforms between Palaeocene and Eocene strata suggest a climatic overprint on river discharge and sedimentation. Upper Palaeocene meandering channel deposits encased in well-drained floodplain strata are indicative of perennial discharge under a semi-arid climate, whereas lower Eocene low-sinuosity channel fills, displaying evidence for transcritical flows and abundant in-situ vegetation, point to intermittent runoff patterns consistent with a humid and seasonal climate. An evolution in atmospheric moisture at the Palaeocene–Eocene boundary from arid to humid conditions has been reported across the Tethys region, and linked to global climatic perturbations of the Palaeocene–Eocene Thermal Maximum.

Outcomes of endovascular thrombectomy for ischaemic stroke among nonagenarians with and without pre-existing dependency

BackgroundOur aim was to compare the outcomes of treatment with endovascular thrombectomy for pre-stroke dependent versus pre-stroke independent among the very elderly ≥90 years. MethodsA retrospective cohort study was performed on 106 patients ≥90 years who underwent endovascular thrombectomy for ischaemic stroke in Western Australia between June 2016 and September 2021. Patient, stroke and procedural details along with inpatient progress and outcome at 90 days were recorded. Patients were divided into Group A (pre-stroke modified Rankin Scale 0-2) and Group B (pre-stroke modified Rankin Scale >2). Primary outcome measure was functional status at 90 days post-stroke, with favourable clinical outcome defined as a 90-day mRS category equal to the patients’ respective pre-stroke mRS category. Secondary outcome measures include successful reperfusion, symptomatic intracranial haemorrhage, hospital length-of-stay, change in accommodation to an aged care facility, and mortality during admission, at 90 days and one year. Results61 patients were allocated to Group A and 45 to Group B. There was none with pre-stroke mRS 5. Group B had more pre-existing cognitive impairment, aged care facility residents, higher median age and lower Alberta Stroke Program Early CT Score. For primary outcome measure, 38 % of patients in Group A and 49 % in Group B achieved a favourable clinical outcome. The difference was not significant (p=0.3408). For secondary outcome measures, Group B had a significantly higher 90-day mortality rate at 47 % versus 24 % in Group A (p=0.03). All other secondary outcome measures were similar between the two groups. These include the rate of successful reperfusion and symptomatic intracranial haemorrhage, hospital length-of-stay, new transition into an aged care facility, inpatient mortality rate and 1-year mortality rate. ConclusionWhen treated with endovascular thrombectomy for ischaemic stroke, nonagenarians with pre-existing dependency achieved a rate of favourable functional outcome comparable with their independent peers, although they also had higher 90-day mortality rate.

Changes in accommodation disorders in children with anisometropic amblyopia and hypermetropia

Background. Accommodation disorders in children with hypermetropia is one of the main factors in emmetropization disorders and maintenance of image defocusing. The most severe changes in accommodation are observed in children with anisometropia and hyperopia.The aim of the work. To evaluate the changes in the accommodative function of the eye in children with hyperopia, amblyopia, who underwent refractive laser surgery (RLS), as well as in children with spectacle and contact lens correction in combination with pleoptic treatment.Methods and materials. Group 1 consisted of 30 children after RLS; group 2 consisted of 29 children who had spectacle correction; group 3 consisted of 26 children who had soft contact lens correction; all children received pleoptic treatment. Clinical examination included the analysis of objective reserves of relative accommodation (RRA) and objective accommodative response (OAR) with an open field autorefractometer, and the results of accommodation measurement.Results. In 1.5 years, statistically significant changes were observed in the coefficient of accommodation response (CAR) of the amblyopic eye between the groups 1 and 2 – 0.12 ± 0.02 and 0.00 ± 0.1 relative units, respectively (p = 0.01). Similar statistically significant changes were obtained in OAR and objective RRA of the amblyopic eye. OAR in the group 1 was –2.1 ± 0.67 dpt, in the group 2 – –1.38 ± 0.19 dpt (p = 0.01). At the end of the observation, the OAR in the group 1 was –2.1 ± 0.67 dpt, the objective RRA – –2.1 ± 0.67 dpt; in the group 2 the OAR was –1.38 ± 0.19 dpt (p = 0.01), the objective RRA – –1.38 ± 0.19 dpt (p = 0.01). There were no statistically significant changes in these parameters of the amblyopic eye between the groups 1 and 3.Conclusion. There was an improvement of accommodation disorders in children with anisometropia, hyperopia and amblyopia after refractive laser surgery and in children with contact lens correction. Due to a decrease in the refractive indices of the amblyopic eye, the values of CAR, OAR and objective RRA after refractive laser surgery tended to be closer to the normal values.

Ultrasound-Guided Occipital Nerve Block in the Management of Refractory Headache and Its Outcomes: A Prospective Study

Abstract Purpose Headache severely impacts health and lifestyle, causing distress and leading to accommodative changes in affected individuals. Treatment options available for refractory headache range from a conservative approach to advanced forms. The purpose of our study was to evaluate the effectiveness of ultrasound-guided occipital nerve block (ONB) in the management of refractory headaches using visual analog scale (VAS) score and Barrow Neurological Institute Pain Intensity Score (BNIPIS). Methods A study sample of 30 eligible patients with refractory headaches including occipital neuralgia, migraine, tension headache, cluster headache, and vascular headaches aged between 18 and 65 years were included in our study. VAS and BNIPIS were noted for each patient before and after the procedure. ONB was given around the target nerve under aseptic precaution. Two milliliters of 0.5% bupivacaine was used as an injection solution for all patients. Results The mean VAS score in acute pain at pre-treatment and post-treatment after 24 hours and 3 months was found as 7.53, 1.53, and 3.20, whereas in chronic pain the score was 8.13, 3.07, and 5.87, respectively. Pre-treatment pain levels in acute and chronic subjects in BNIPIS IV and V category shifted to category I and II after 24 hours (postinjection) that later were recorded II and III, respectively, after 3 months. Conclusion Standard treatment guidelines are given by the international headache association for the management of headaches. The use of ONB is well advocated and practiced for a long time. In our study, we found that the use of greater occipital nerve block reduced pain levels affecting VAS and BNIPIS, which was more effective in acute cases than in chronic cases.

Anterior Segment Biometry During Accommodation After Posterior Chamber Phakic Implantable Collamer Lens Implantation.

To evaluate the dynamic changes in anterior segment parameters during accommodation following Implantable Collamer Lens (ICL) implantation with swept-source optical coherence tomography (SS-OCT). Under the accommodation of 0.00 diopters (D), 3.00 D, and maximum amplitude, SS-OCT was used to examine the anterior segment parameters, including ICL vault, ICL depth (the distance between the corneal endothelium and the posterior surface of ICL), crystalline lens thickness, anterior chamber depth, and various parameters of the anterior chamber angle, comprising angle opening distance, angle recess area, trabecular iris space area, and trabecular iris angle. During accommodation, the ICL vault showed a significant decrease from baseline (536 ± 278 μm) to 3.00 D (522 ± 281 μm), followed by an increase from 3.00 D to maximum amplitude (548 ± 306 μm) (analysis of variance [ANOVA], P < .001). Four eyes (2.61%) exhibited a decrease in ICL vault to less than 100 μm (47 ± 32 μm) at maximum accommodation. The ICL depth decreased significantly as accommodation increased (ANOVA, P < .001). Crystalline lens thickness increased, whereas anterior chamber depth decreased during accommodation (ANOVA, P < .001). The anterior chamber angle widened during 3.00 D of accommodation but narrowed at maximum accommodation, leading to significant changes in the angle opening distance, angle recess area, trabecular iris space area, and trabecular iris angle during accommodation (ANOVA, P < .001 for all). The anterior segment, including ICL vault and anterior chamber angle, undergo significant dynamic changes during accommodation. These accommodative changes may require careful monitoring for the surgery design of ICL implantation. [J Refract Surg. 2024;40(3):e164-e172.].

Architecture of Oxfordian coral buildups along the Atlantic margin of Morocco

Oxfordian (Upper Jurassic) coral buildups developed widely in Tethys and Atlantic realms, during a time when paleoclimate potentially swung between greenhouse climate and cold snaps. Buildups were constructed by platy and branching corals, sponges and microbialites. Although their initiation is commonly linked to the Upper Jurassic global transgression, a number of global and local factors may have influenced buildup growth and demise (e.g. climate, shelf geometry, detrital input). Extensive outcrops of Oxfordian buildups in Morocco provide an opportunity to investigate the relationship between external drivers and buildup fauna and architecture. Here we show that the interplay of local accommodation changes, rising sea water temperature, and increasing pCO2 linked to the onset of the Middle Oxfordian global transgression were the main drivers for buildup initiation, which was synchronous across the basin. The demise of the coral buildups in Morocco was linked to a regression, dated no later than Upper Oxfordian, the establishment of partly evaporitic conditions across the basin, and to localized influx of coarse-grained siliciclastics, the latter likely driven by synsedimentary tectonic activity. Serial logged sections, outcrop panoramas and detailed facies analysis show that low-relief deeper-water buildups of Dimorpharaea platy corals evolved into higher-relief diversified buildups where shallower-water reworking produced coral rubble and large clinoforms. Buildup diachronicity is apparent, with younger coral bioherms growing in the depressions created between the initial bioherms. Size of buildups ranges from 2 m wide and 0.5 m thick, to 700 m wide and 80 m thick. The outcrops provide constraints on geobody architecture and heterogeneity in the subsurface of Morocco and North America, where facies-controlled dolomitization of high-energy buildup and clinoform facies is a main driver for porosity development.

Placing constraints on the nature of short‐term eustatic curves

AbstractThe isolation of the eustatic signal from the sedimentary record is a challenging task, and accordingly, there is no consensus on the magnitude and pace (rate) of eustatic events in the geological record. Here we critically assess various published short‐term Cretaceous eustatic curves using insights from forward stratigraphic modelling. We generate a range of simulations with varying eustatic rates and sediment supply against a background of constant subsidence. From these, we generate statistics on the accommodation change associated with the various systems tracts for different sediment supply. We quantify the minimum rate needed to generate transgressive systems tracts (TST). Using this threshold and average subsidence rates for passive margins and intracratonic basins, we document some key challenges with a range of Cretaceous eustatic curves. While it is possible to complexify, this approach through the inclusion of other parameters, our results provide a framework for evaluating eustatic (or relative sea level) curves in terms of the implied rate of change of accommodation. Given these caveats, we also show that many estimates of the magnitude of short‐term transgressions are of insufficient rate to generate observable TST. Further, our work places an upper limit on the time frame over which aquifer and thermo‐eustasy can have observable impacts on the rock record, providing support for the action of glacio‐eustasy during the Cretaceous.

Aptian major changes in accommodation. New sedimentary evidence from the Maestrat Basin (E Iberia)

Global sea-level fluctuations with amplitudes of tens of metres and durations between 0.5 and 3 Myr are well-known oceanographic events of the Cretaceous Period. During recent years, major Cretaceous changes in accommodation recorded in different basins have been mainly interpreted as eustatically driven. Two episodes of major relative sea-level fall and rise of late early and early late Aptian age were investigated in the Maestrat Basin (E Iberian Peninsula). Previously documented in eight outcrops, these Aptian records of major changes in accommodation have now been identified in five additional localities within the basin, suggesting at least a basin-wide significance of these relative sea-level fluctuations. The records of relative sea-level fall analysed are associated with the local development of incised valleys and forced regressive wedges. Two upper lower Aptian incised valleys, which are downcutting highstand platform carbonates dominated by rudists and corals, were studied and show depths of approximately 10 and 80 m. The incision depths measured indicate amplitudes of relative sea-level variations in the order of tens of metres. During subsequent base-level rise, the lower part of these incised valleys was respectively infilled with orbitolinid limestones and high-energy carbonate deposits influenced by tides. Further evidence of major relative sea-level drop and rise during the late early Aptian includes a detached backstepping carbonate platform of reduced extension, underlain and overlain by basinal marly deposits, which flourished basinwards of a highstand platform margin. Although incised valleys or smaller-scale incisions are local features, evidence for relative declines in sea level can be identified from other evidence. For example, by the development of palaeokarst or by the presence of sharp or slightly erosive stratigraphic surfaces covered by deposits of higher energy influenced by tides, as observed in the late Aptian examples investigated herein. Comparable Aptian sedimentary features of subaerial exposure and subsequent transgressive genetic types of deposits have been observed in other basins across different tectonic plates, indicating that eustasy likely played a role in controlling accommodation changes during this stage. The discovery of new evidence for major relative Aptian sea-level fluctuations in various outcrops within the Maestrat Basin calls for further investigation in other underexplored Aptian platform carbonate successions in this basin. These investigations would contribute to a more accurate understanding of oceanographic dynamics during the Aptian Stage along the western margin of the Alpine Tethys.

Changes in pupil size, ocular wavefront aberrations, and accommodation in healthcare workers using FFP3 masks.

To evaluate changes in pupil size, ocular wavefront aberrations (WA), and accommodation in healthcare workers after 4-h usage of Filtering Facepiece class 3 (FFP3) masks. This prospective study included 22 healthy healthcare workers. Pupil size, ocular WA, and accommodation changes before and after FFP3 mask usage were evaluated using a Hartmann Schack aberrometer. Accommodative responses to stimulus ranging from 0 to 5 diopters (D) in increments of 0.5 D were assessed. Ocular high-order aberrations (HOAs) were recorded at baseline and at every accommodative stimulus. Oxygen saturation (SpO2) was measured by pulse oximetry before and after the mask usage. The mean age was 36.6 ± 8.5 years. The SpO2 significantly decreased from 98.95 to 97.95% after usage of the FFP3 mask (p < 0.001). The mean pupil size did not significantly differ before (6.22 ± 0.75 mm) and after (6.38 ± 0.83 mm) the 4-h mask usage (p = 0.093). The mean total RMS of the total HOAs was 0.36 ± 0.17 before and 0.39 ± 0.15 after the mask usage (p = 0.071). Post-mask accommodation showed a significant decrease at the 2 D (p = 0.041), 2.5D (p = 0.022), and 3 D (p = 0.025) stimuli. The present study shows that after 4 h-usage of FFP3 mask, both SpO2 and accommodative response to increasing stimuli might be significantly decreased.

The eight architectural zones of nonmarine basins

Abstract One of the goals of sequence stratigraphy is to model the conditions that generate stratigraphic architecture at outcrop to basin scales. Accommodation and sedimentation are the principal variables included in sequence-stratigraphic models that describe facies architecture in marine successions. Similar models exist to describe wholly nonmarine architecture. Distinct models are commonly applied to basins containing predominantly lacustrine or predominantly fluvial facies, which can make it difficult to apply models to the entire history of a basin that may include both lacustrine-dominated or fluvial-dominated phases, depending on climatic and tectonic conditions. To account for these changing conditions over the history of nonmarine basins, we present a conceptual three-dimensional model that describes the potential architectural patterns under specific combinations of accommodation, sediment flux, and water balance. Sectors of the model delineate where basins are underfilled or overfilled with respect to accommodation and limited with respect to sediment and water, creating eight zones with different implications for the development of facies architecture. Different types of basins (e.g., foreland, extensional, pull-apart, intracratonic) show broadly different trends in architecture through time. Subtle changes in accommodation, sedimentation, and water balance in the model correspond to shifts in facies architecture between lithostratigraphic units, but architectural transitions within individual basins are more important indicators of evolving basin conditions than comparisons among all basins. This model may serve as a guide for comparing the influence of distinct drivers of architecture among different types of basins as well as identifying important intervals of change during the history of basin filling. The availability of commensurate data on the history of accommodation, sedimentation, and water balance is, however, an ongoing challenge to reconstructing complete basin histories. Future analyses will test how well predicted facies stacking patterns compare to observed nonmarine stratigraphic successions resulting from the combination of accommodation, sediment flux, and water balance during the history of basin filling.