Prevalence and Associated Factors of Cataract, Cataract Surgery and Postoperative Outcome in an Old Population in Russia: The Ural Very Old Study.

Purpose: To assess prevalence of cataract and cataract surgery in a very old population in Russia. Design: Population-based study. Participants: The Ural Very Old Study included 1526 (81.1%) participants of 1882 eligible individuals aged >85 years. Methods: Series of ophthalmological examinations. Main Outcome Measures: Prevalence of cataract and cataract surgery. Results: The study included 1163 (76.3%) individuals with lens information. Cataract surgery had been performed in 469 right eyes (41.0%; 95% confidence interval [CI]: 38.1-43.9) (92.1% with posterior chamber intraocular lens [IOL]; 4.7% with multifocal IOL) and 479 left eyes (41.6%; 95% CI: 38.7-44.4) (92.7% with posterior chamber IOL; 4.2% with multifocal IOL). Cataract surgery had been performed in at least one eye for 610 (52.5%) individuals. Higher prevalence of previous cataract surgery correlated (multivariable analysis) with lower IOP (OR: 0.92; 95% CI: 0.88-0.95), glaucomatous optic nerve damage stage (OR: 1.20; 95% CI: 1.05-1.36), and better visual acuity (OR: 0.67; 95% CI: 0.51-0.89). Postoperative best corrected visual acuity was reduced to moderate-to-severe vision impairment (MSVI) in 202 eyes (44.6%; 95% CI: 40.0-49.2) and to blindness in 53 eyes (11.7%; 95% CI: 8.7-14.7). Causes of postoperative MSVI were age-related macular degeneration (AMD) (34.2%), glaucoma (13.9%), and secondary cataract (5.4%). Causes for blindness were AMD (24.5%), glaucoma (18.9%), corneal opacifications (15.8%) and myopic macular degeneration (11.3%). Yttrium Aluminum Garnet-laser capsulotomy had been performed in 6 (1.3%) of 469 right eyes and 12 (2.5%) of 479 left eyes. Prevalence of nuclear cataract and cortical cataract was 604/671 (90.0% in phakic eyes; 51.9% in the whole study population) and 97.9% eyes (48.4% in total study population). Cataract caused bilateral MSVI and blindness in 28.2% (95% CI: 25.6-30) and 2.9% (95% CI: 1.9-3.9), respectively, of all study participants. Conclusions: Despite a relatively high prevalence of cataract surgery, this multiethnic cohort >85 years of aged from Russia showed a high prevalence of cataract-related MSVI and blindness. Main causes for postoperative MSVI (prevalence: 44.6%) and blindness (prevalence: 11.7%) were AMD, glaucoma, corneal opacifications, and myopic macular degeneration. Almost all individuals aged 85+ years need cataract surgery, despite limited chance of postoperative good vision. Financial Disclosures: The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Blind individuals' enhanced ability to sense their own heartbeat is related to the thickness of their occipital cortex.

Blindness is associated with heightened sensory abilities, such as improved hearing and tactile acuity. Moreover, recent evidence suggests that blind individuals are better than sighted individuals at perceiving their own heartbeat, suggesting enhanced interoceptive accuracy. Structural changes in the occipital cortex have been hypothesized as the basis of these behavioral enhancements. Indeed, several studies have shown that congenitally blind individuals have increased cortical thickness within occipital areas compared to sighted individuals, but how these structural differences relate to behavioral enhancements is unclear. This study investigated the relationship between cardiac interoceptive accuracy and cortical thickness in 23 congenitally blind individuals and 23 matched sighted controls. Our results show a significant positive correlation between performance in a heartbeat counting task and cortical thickness only in the blind group, indicating a connection between structural changes in occipital areas and blind individuals' enhanced ability to perceive heartbeats.

[The effect of various visual impairments on the daily activities of older patients.]

Visual impairment due to ophthalmological diseases significantly affects functional activity in everyday life, since good eyesight is crucial in daily activities. Data from 837 respondents were studied, allowing for analysis of such medical and demographic indicators as age, gender, level of education, visual acuity arterial hypertension and diabetes mellitus. To measure functional status, the main activities in daily life (ADL) and instrumental activities in daily life (IADL) were evaluated using a modified version of the Katz scale and the IADL OARS scale. Statistical methods of Mantel-Hansel Chi-squared analysis were used to assess differences in the prevalence of functional blindness and visual deficit. The study showed that medical and demographic factors have a relatively smaller impact on vision deficiency compared to functional blindness, with age being a significant factor in both cases. Among the medical and demographic factors, the age of patients, as well as diabetes mellitus, significantly increase the development of visual deficiency and functional blindness. Functional blindness, in comparison with visual deficiency, causes more significant restrictions on activities in everyday life and instrumental activities in everyday life, and also causes dependence on help from others.

A novel homozygous nonsense variant in CABP4 causing stationary cone/rod synaptic dysfunction.

INTRODUCTION: Variants in the CABP4 gene cause a phenotype to be included in the spectrum of congenital stationary night blindness, though some reports suggest that the clinical abnormalities are more accurately categorized as a synaptic disease of the cones and rods. We report a novel homozygous nonsense variant in CABP4 in a patient complaining of non-progressive reduced visual acuity and photophobia but not nyctalopia. METHODS: Complete ocular examination, fundus photographs, autofluorescence, optical coherence tomography, electroretinography, and targeted sequencing of known inherited retinal disease-associated genes. RESULTS: A 25-year-old man monitored for 13 years complains of a lifelong history of stable reduced visual acuity (20/150), impaired color vision (1 of 14 plates), small-amplitude nystagmus, and photophobia without nyctalopia. He is also hyperopic (+7D), and his electroretinography shows significantly reduced rod and cone responses. Targeted genetic analysis revealed a novel homozygous variant in the CABP4 gene at c.181C>T, p. (Gln61*) underlying his clinical presentation. CONCLUSIONS: A novel variant in CABP4 is associated with stationary cone and rod dysfunction resulting in decreased acuity, color deficit, and photophobia, but not nyctalopia.

Primary CNS Burkitt Lymphoma Presenting as Sudden Bilateral Blindness in a Patient With Underlying Kabuki Syndrome: A Case Report.

Burkitt lymphoma is an aggressive B-cell non-Hodgkin lymphoma (NHL). Primary CNS lymphoma (PCNSL) is a rare disease, and the subtype of Burkitt lymphoma presenting as a sole CNS lesion is an even rarer diagnosis. Acute sudden blindness is a rare presenting symptom of PCNSL or NHL in general. We present an interesting case of a four-year-old boy with dysmorphic features whose visual examination showed a sudden bilateral loss of vision. There was bilateral eye proptosis and complete ptosis. Extraocular muscles were fixed straight. The pupils were fixed and mid dilated bilaterally and there was grade 3/4 papilledema in both eyes. Neuroimaging showed a mass in the base of the skull, extending to orbits and sinuses. A cervical biopsy of the enlarged lymph nodes was taken and a histopathological diagnosis of Burkitt lymphoma was made. Genetic analysis showed a GNB1 mutation, and the patient was diagnosed with Kabuki syndrome by a pediatrician, based on characteristic dysmorphic features. Treatment with steroids and chemotherapy was initiated.

Visual experience modulates the sensitivity to the distributional history of words in natural language.

Different experiential traces (i.e., linguistic, motor, and perceptual) are likely contributing to the organization of human semantic knowledge. Here, we aimed to address this issue by investigating whether visual experience may affect the sensitivity to distributional priors from natural language. We conducted an independent reanalysis of data from Bottini et al., in which early blind and sighted participants performed an auditory lexical decision task. Since previous research has shown that semantic neighborhood density-the mean distance between a target word and its closest semantic neighbors-can influence performance in lexical decision tasks, we investigated whether vision may alter the reliance on this semantic index. We demonstrate that early blind participants are more sensitive to semantic neighborhood density than sighted participants, as indicated by the significantly faster response times for words with higher levels of semantic neighborhood density shown by the blind group. These findings suggest that an early lack of visual experience may lead to enhanced sensitivity to the distributional history of words in natural language, deepening in turn our understanding of the strict interplay between linguistic and perceptual experience in the organization of conceptual knowledge.

Accessible Point-and-Tap Interaction for Acquiring Detailed Information about Tactile Graphics and 3D Models.

We have devised a novel "Point-and-Tap" interface that enables people who are blind or visually impaired (BVI) to easily acquire multiple levels of information about tactile graphics and 3D models. The interface uses an iPhone's depth and color cameras to track the user's hands while they interact with a model. When the user points to a feature of interest on the model with their index finger, the system reads aloud basic information about that feature. For additional information, the user lifts their index finger and taps the feature again. This process can be repeated multiple times to access additional levels of information. For instance, tapping once on a region in a tactile map could trigger the name of the region, with subsequent taps eliciting the population, area, climate, etc. No audio labels are triggered unless the user makes a pointing gesture, which allows the user to explore the model freely with one or both hands. Multiple taps can be used to skip through information levels quickly, with each tap interrupting the current utterance. This allows users to reach the desired level of information more quickly than listening to all levels in sequence. Experiments with six BVI participants demonstrate that the approach is practical, easy to learn and effective.

Transient cortical blindness following peripheral vascular trauma: A case report.

Cortical blindness is characterized by unilateral or bilateral vision loss despite an intact pupillary reflex, full extraocular movements, and normal fundoscopic examination. Common causes include stroke, cardiac emboli, head trauma or rarely, a hypoxic-ischemic event which results to decreased perfusion to the occipital lobes supplied by the posterior cerebral artery. Imaging with computed tomography is usually diagnostic documenting stroke or embolization as well as ensuring an intact cerebral circulation. Prognosis largely depends on the etiology as most reports document an irreversible condition or at least the patient is left with some residual visual symptoms. We present a case of a 25-year-old male who underwent brachial artery repair with reverse saphenous vein graft interposition after sustaining a right upper arm laceration associated with massive hemorrhage and shock due to delayed consult. He presented with profound bilateral loss of vision 12 h after surgery characterized as right homonymous hemianopsia. Computed tomography of the brain demonstrated ischemic infarcts in the occipital lobes. Close observation was instituted, and his symptom resolved spontaneously within a week. This case highlights the importance of considering atypical causes of perioperative vision loss as early recognition and timely diagnosis are essential to improve patient outcomes. To our knowledge, this is the first report of transient cortical blindness after peripheral vascular trauma.

Multitasking Induced Contextual Blindness.

OBJECTIVE: To examine the impact of secondary task performance on contextual blindness arising from the suppression and masking of temporal and spatial sequence learning. BACKGROUND: Dual-task scenarios can lead to a diminished ability to use environmental cues to guide attention, a phenomenon that is related to multitasking-induced inattentional blindness. This research aims to extend the theoretical understanding of how secondary tasks can impair attention and memory processes in sequence learning and access. METHOD: We conducted three experiments. In Experiment 1, we used a serial reaction time task to investigate the impact of a secondary tone counting task on temporal sequence learning. In Experiment 2, we used a contextual cueing task to examine the effects of dual-task performance on spatial cueing. In Experiment 3, we integrated and extended these concepts to a simulated driving task. RESULTS: Across the experiments, the performance of a secondary task consistently suppressed (all experiments) and masked task learning (experiments 1 and 3). In the serial response and spatial search tasks, dual-task conditions reduced the accrual of sequence knowledge and impaired knowledge expression. In the driving simulation, similar patterns of learning suppression from multitasking were also observed. CONCLUSION: The findings suggest that secondary tasks can significantly suppress and mask sequence learning in complex tasks, leading to a form of contextual blindness characterized by impairments in the ability to use environmental cues to guide attention and anticipate future events. APPLICATION: These findings have implications for both skill acquisition and skilled performance in complex domains such as driving, aviation, manufacturing, and human-computer interaction.

Permanent unilateral visual loss and orbital compartment syndrome following unilateral frontal craniotomy: illustrative case.

BACKGROUND: Vision loss following supine craniotomy is an unexpected and devastating complication for the patient and the operating team. Postoperative vision loss (POVL) is commonly associated with cardiac, spinal, neck, and prone head surgeries, as they share common risk factors, such as a prone position, intraoperative hypotension, a longer anesthesia duration, and the use of vasopressors. Herein, the authors report a case of irreversible vision loss following a frontal craniotomy in the supine position together with a review of the literature. All published cases in the literature since the first reported case in 1970 are summarized. Possible etiologies and proposed preventive measures are discussed. OBSERVATIONS: Different pathologies, such as vascular, intra-axial, and extra-axial lesions, are associated with POVL and have similar clinical courses and nonrecovery rates, which raises the question of whether POVL begins during the exposure part of these surgeries. LESSONS: Preventive measures could include avoiding direct ocular pressure during flap reflection, the use of elastic bands or fishhooks to avoid stretching the orbital contents and impairing venous outflow, and a careful review of the venous drainage of frontal tumors, which could help avoid unnecessary large venous thrombi or waxing. The role of intraoperative visual neurophysiological monitoring in predicting POVL requires further exploration. https://thejns.org/doi/10.3171/CASE2434.

Essential Occupational Therapy Competencies for Low Vision and Blindness.

Background. The prevalence of low vision and blindness in persons across the lifespan means that occupational therapists will encounter these conditions across all areas of practice. Practitioners must be equipped with competencies necessary to recognize and respond to vision loss-related concerns. Purpose. This study sought to identify essential occupational therapy competencies when providing services to people with low vision and blindness. Method. The study employed a three-phase modified Delphi methodology administered through online surveys and focus group. Respondents included people with low vision or blindness, professionals with special expertise in low vision/blindness, and occupational therapists in other practice areas. Data were analyzed using an iterative, consensus-generating strategy involving quantitative analysis of competencies, qualitative input, and expert panel review. Findings. The process yielded a 51-item competency framework organized into six domains. Implications. The framework provides the foundation for a common curriculum for Canadian occupational therapy programs and for the creation of educational resources.

Restoration of cone-circuit functionality in the regenerating adult zebrafish retina.

Unlike humans, teleosts like zebrafish exhibit robust retinal regeneration after injury from endogenous stem cells. However, it is unclear if regenerating cone photoreceptors regain physiological function and integrate correctly into post-synaptic circuits. We used two-photon calcium imaging of living adult retina to examine photoreceptor responses before and after light-induced lesions. To assess functional recovery of cones and downstream outer retinal circuits, we exploited color opponency; UV cones exhibit intrinsic Off-response to blue light, but On-response to green light, which depends on feedback signals from outer retinal circuits. Accordingly, we assessed the presence and quality of Off- vs. On-responses and found that regenerated UV cones regain both Off-responses to short-wavelength and On-responses to long-wavelength light within 3 months after lesion. Therefore, physiological circuit functionality is restored in regenerated cone photoreceptors, suggesting that inducing endogenous regeneration is a promising strategy for human retinal repair.

No Electrophysiological Evidence for Semantic Processing During Inattentional Blindness.

A long-standing question concerns whether sensory input can reach semantic stages of processing in the absence of attention and awareness. Here, we examine whether the N400, an event related potential associated with semantic processing, can occur under conditions of inattentional blindness. By employing a novel three-phase inattentional blindness paradigm designed to maximise the opportunity for detecting an N400, we found no evidence for it when participants were inattentionally blind to the eliciting stimuli (related and unrelated word pairs). In contrast, participants noticed the same task-irrelevant word pairs when minimal attention was allocated to them, and a small N400 became evident. When the same stimuli were fully attended and relevant to the task, a robust N400 was observed. In addition to univariate ERP measures, multivariate decoding analyses were unable to classify related from unrelated word pairs when observers were inattentionally blind to the words, with decoding reaching above-chance levels only when the words were (at least minimally) attended. By comparison, decoding reached above-chance levels when contrasting word pairs with non-word stimuli, even when participants were inattentionally blind to these stimuli. Our results also replicated several previous studies by finding a "visual awareness negativity" (VAN) that distinguished task-irrelevant stimuli that participants reported to have perceived compared with those that were not perceived, and a P3b (or "late positivity") that was evident only when the stimuli were task relevant. Together, our findings suggest that semantic processing might require at least a minimal amount of attention.

Short- and Long-Range Dispersal by Members of the Simulium damnosum Complex (Diptera: Simuliidae), Vectors of Onchocerciasis: A Review.

Blackfly members of the Simulium damnosum complex are major vectors of the parasite that causes onchocerciasis in Africa and Yemen, with other vector species involved in a few localized areas of Africa and in the Neotropics. Although the life cycle of these blackflies is linked to fast-flowing rivers, they can travel long distances (up to at least 500 km), calling into question how transmission zones are defined. Knowledge of the short- and long-range dispersal of these vectors could inform where control interventions and monitoring are necessary if targets for onchocerciasis elimination are to be met. Yet, research on blackfly dispersal has been limited and fragmented over the last 70 years. Here, we review the literature on the dispersal of onchocerciasis vectors, and we show the need for further research to establish how far larvae can travel downstream; the extent to which adults invade transmission zones; and whether adults migrate in a series of successive short movements or in single long-distance shifts, or use both methods.

Smart speakers and skill use: what do we know?

Personal smart technologies are becoming increasingly interwoven into everyday life, yet the usability and usefulness for some of these off-the-shelf technologies for persons with disabilities has yet to be determined. Smart speakers with both their native and downloadable functionalities (skills) have great potential to support individuals with disabilities through communication functionalities, smart home integrations, and more. However, the potential for usefulness does not always translate to how something is actually perceived or used in the real-world. Therefore, the objective of this qualitative study was to gather insight from individuals with disabilities on their experiences with smart speakers and smart speaker skills. Participant feedback highlighted several primary themes: (1) external factors that might influence extent of, and advancement in smart speaker use, (2) Smart speaker use barriers, (3) Smart speaker use facilitators, and (4) Smart speaker uses specific to individuals with disabilities. Continued research and development is needed to help ensure that commercially available technologies are designed with universal design principles that will ensure accessibility for all potential users.

Smart speaker skills are being used for smart home management by persons with disabilities, but these functionalities are not without barriers.Persons with various disabilities should be involved in the development and translation of smart speaker functions that are intended to, or that could, support the needs of this population.

Profile and risk factors of sight-threatening retinopathy of prematurity: Experience from SNCU in North India.

BACKGROUND: This research aimed to identify the clinical profile and risk factors of retinopathy of prematurity (ROP) among "at-risk" newborns treated at a sick newborn care unit (SNCU) located at high altitude in North India, with the intention of contributing to formulate regional and national ROP screening guidelines. MATERIALS AND METHODS: In a prospective observational study from 2021 to 2022, outborn and inborn babies eligible for ROP screening were screened. RESULTS: Total 39/122 screened neonates had laser for Type 1 ROP, and 22/39 (56.4%) had aggressive ROP (AROP). The average birth weight (BW) was 1803.87 g, and the average gestational age was 34 weeks. Respiratory distress, bronchopulmonary dysplasia, sepsis, and apnea were present in 57.3%, 13%, 52.5%, and 25.4%, respectively. Sight-threatening ROP was present in 50% below 28+6 weeks, 27% between 29 and 30+6 weeks, 52% between 31 and 33+6 weeks, and 15% with gestation >34 weeks. Two babies with Type 1 ROP weighed >2 kg and one had AROP. Upon regression analysis, BW <1500 g, gestation <32 weeks, oxygen >48 h, clinical sepsis, total SNCU stay >14 days, continuous positive airway pressure support with oxygen >50%, and >10 days to achieve full feeds were associated with severe ROP. Caffeine to treat apnea and kangaroo mother care reduced ROP. None had short-term unfavorable outcome. CONCLUSION: With similar infrastructure and work force shortage in most SNCUs, these findings can be generalized. The burden of Type 1 and AROP is increasing, as seen in higher gestation and BWs. This needs revision of ROP screening criteria at local and national level. It is crucial to emphasize on the importance of pediatrician and ophthalmologist collaboration, early ROP screening, diagnosis, and treatment to stop disease progression to severe ROP.

Vision-related quality of life after unilateral occipital stroke.

BACKGROUND/OBJECTIVES: Stroke damage to the primary visual cortex induces large, homonymous visual field defects that impair daily living. Here, we asked if vision-related quality of life (VR-QoL) is impacted by time since stroke. SUBJECTS/METHODS: We conducted a retrospective meta-analysis of 95 occipital stroke patients (female/male = 26/69, 27-78 years old, 0.5-373.5 months poststroke) in whom VR-QoL was estimated using the National Eye Institute Visual Functioning Questionnaire (NEI-VFQ) and its 10-item neuro-ophthalmic supplement (Neuro10). Visual deficit severity was represented by the perimetric mean deviation (PMD) calculated from 24-2 Humphrey visual fields. Data were compared with published cohorts of visually intact controls. The relationship between VR-QoL and time poststroke was assessed across participants, adjusting for deficit severity and age with a multiple linear regression analysis. RESULTS: Occipital stroke patients had significantly lower NEI-VFQ and Neuro10 composite scores than controls. All subscale scores describing specific aspects of visual ability and functioning were impaired except for ocular pain and general health, which did not differ significantly from controls. Surprisingly, visual deficit severity was not correlated with either composite score, both of which increased with time poststroke, even when adjusting for PMD and age. CONCLUSIONS: VR-QoL appears to improve with time postoccipital stroke, irrespective of visual deficit size or patient age at insult. This may reflect the natural development of compensatory strategies and lifestyle adjustments. Thus, future studies examining the impact of rehabilitation on daily living in this patient population should consider the possibility that their VR-QoL may change gradually over time, even without therapeutic intervention.

Effect of a self-care promoting program on engagement in self-care behaviors and health-related outcomes among persons with type 2 diabetes and diabetic retinopathy: A single-blind randomized controlled trial.

Background: Diabetic retinopathy (DR) is the most common microvascular complication of diabetes, leading to visual impairment and eventual blindness. Promoting self-care behaviors is crucial in controlling DR progression and preventing blindness. Objective: This study aimed to investigate the effects of a Self-Care Promoting Program (SCPP) on engagement in self-care behaviors, HbA1c levels, visual acuity (VA), severity of DR, and vision-related quality of life (VRQoL) among individuals with type 2 diabetes and DR. Methods: This study employed a single-blind randomized controlled trial design to compare SCPP with conventional diabetic care interventions (standard care). The SCPP was based on the Self-Care of Chronic Illness Theory, Self-efficacy theory, and the Association of Diabetic Care and Education Specialist (ADCES) guidelines incorporating health education, self-care maintenance, monitoring, and management skills training over 12 weeks. Ninety-eight participants were randomly allocated to the experimental or control group (n = 49 per group). While the experimental group received SCPP alongside standard care, the control group received standard care alone. Data collection occurred between May 2022 and March 2023 and included demographic information, the Self-Care of Diabetes Index questionnaire (SCODI), the self-care for diabetes eye care questionnaire (SCFDE), the impact of visual impairment questionnaire (IVI-Thai version), and retinal images for DR severity grading. Data analysis utilized descriptive statistics, Chi-Square tests, t-tests, and MANOVA. Results: Following 8 and 16 weeks of SCPP, the experimental group had significantly higher mean scores in engagement with self-care and eye-care behaviors compared to the control group (p <0.001). The highest scores were observed in self-care and eye-care confidence behaviors, followed by maintenance, monitoring, and management. Furthermore, HbA1c levels and VRQoL significantly decreased and were lower than those of the control group at week 16 (p <0.001 and p <0.05, respectively). However, there were no significant differences in VA, and DR severity increased in both groups by week 16. Conclusion: SCPP benefits individuals with DR, enhancing their confidence and ability to perform, monitor, and manage self-care behaviors. These strategies contribute to improved diabetes management, enhanced quality of life, and reduced DR-related blindness. Integrating SCPP into routine DR management is recommended, with nurses playing a pivotal role in overseeing and driving this integration, highlighting the critical role of nurses in managing this widespread global disease. Trial Registry Number: Thai Clinical Trials Registration (TCTR20230302002).

The modulation of task relevance on emotion-induced blindness depends on whether targets and distractors belong to the same category.

Previous research on emotion-induced blindness (EIB) argues emotional distractors capture attention in a bottom-up manner due to their physical and emotional salience. However, recent research has shown it is controversial whether EIB will be modulated by top-down factors. The present study further investigated whether the magnitude of EIB would be modulated by top-down factors, specifically the emotional relevance between tasks and distractors. Participants were divided into two groups having the same targets except for different task instructions. The orientation judgment group was asked to judge the orientation of the target (an emotionally irrelevant task), and the emotion judgment group was required to judge the emotional valence of the target (an emotionally relevant task). It was found the emotional relevance between tasks and distractors has no modulation on the magnitudes of EIB in two groups when targets and distractors are from different categories (Experiment 1), but a modulation when they are from the same category (Experiment 2). Consequently, we contend top-down task relevance modulates the EIB effect and distractors' priority is regulated by the emotional relevance between tasks and distractors. The current study holds attentional capture by stimulus-driven is unconditional in EIB, while attentional capture by goal-driven requires certain conditions.