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BMC Ophthalmology Apr 2024The purpose of this study was to analyze myopic regression after corneal refractive surgery (CRS) in civilian pilots and to explore the factors that may cause long-term...
BACKGROUND
The purpose of this study was to analyze myopic regression after corneal refractive surgery (CRS) in civilian pilots and to explore the factors that may cause long-term myopic regression.
METHODS
We included civilian pilots who had undergone CRS to correct their myopia and who had at least 5 years of follow-up. We collected retrospective data and completed eye examinations and a questionnaire to assess their eye habits.
RESULTS
A total of 236 eyes were evaluated in this study. 211 eyes had Intrastromal ablations (167 eyes had laser in situ keratomileusis, LASIK, 44 eyes had small incision lenticule extraction, SMILE) and 25 eyes had subepithelial ablations (15 eyes had laser epithelial keratomileusis, LASEK and 10 eyes had photorefractive keratectomy, PRK). The mean preoperative spherical equivalent (SE) was - 2.92 ± 1.11 D (range from - 1.00 to -5.00 D). A total of 56 eyes (23.6%) suffered from myopic regression after CRS. Comparisons of individual and eye characteristics between the regression and non-regression groups revealed statistically significant differences in age, cumulative flight time, postoperative SE (at 6 months and current), uncorrected visual acuity (UCVA), accommodative amplitude (AA), positive relative accommodation (PRA), postoperative period, types of CRS and eye habits. Generalized propensity score weighting (GPSW) was used to balance the distribution of covariates among different age levels, types of CRS, cumulative flying time, postoperative period and continuous near-work time. The results of GPS weighted logistic regression demonstrated that the associations between age and myopic regression, types of CRS and myopic regression, continuous near-work time and myopic regression were significant. Cumulative flying time and myopic regression, postoperative period and myopic regression were no significant. Specifically, the odds ratio (OR) for age was 1.151 (P = 0.022), and the OR for type of CRS was 2.769 (P < 0.001). The OR for continuous near-work time was 0.635 with a P value of 0.038.
CONCLUSIONS
This is the first report to analyze myopic regression after CRS in civilian pilots. Our study found that for each year increase in age, the risk of civilian pilots experiencing myopic regression was increased. Intrastromal ablations had a lower risk of long-term myopia regression than subepithelial ablations. There is a higher risk of myopic progression with continuous near-work time > 45 min and poor accommodative function may be related factors in this specific population.
Topics: Humans; Infant; Retrospective Studies; Cornea; Photorefractive Keratectomy; Visual Acuity; Refraction, Ocular; Keratomileusis, Laser In Situ; Lasers, Excimer; Myopia; Treatment Outcome
PubMed: 38561680
DOI: 10.1186/s12886-024-03399-5 -
Journal of Alzheimer's Disease Reports 2024Cumulative effects of traumatic brain injury is of increasing concern, especially with respect to its role in the etiology and pathogenesis of neurodegenerative...
Changes in Brain Structure and Function in a Multisport Cohort of Retired Female and Male Athletes, Many Years after Suffering a Concussion: Implications for Neuroplasticity and Neurodegenerative Disease Pathogenesis.
BACKGROUND
Cumulative effects of traumatic brain injury is of increasing concern, especially with respect to its role in the etiology and pathogenesis of neurodegenerative diseases, such as Alzheimer's disease, Parkinson's disease, and amyotrophic lateral sclerosis.
OBJECTIVE
Compare regional brain volume and connectivity between athletes with a history of concussion and controls.
METHODS
We evaluated whole-brain volumetric effects with Bayesian regression models and functional connectivity with network-based statistics, in 125 retired athletes (a mean of 11 reported concussions) and 36 matched controls.
RESULTS
Brain regions significantly lower in volume in the concussed group included the middle frontal gyrus, hippocampus, supramarginal gyrus, temporal pole, and inferior frontal gyrus. Conversely, brain regions significantly larger included the hippocampal and collateral sulcus, middle occipital gyrus, medial orbital gyrus, caudate nucleus, lateral orbital gyrus, and medial postcentral gyrus. Functional connectivity analyses revealed increased edge strength, most marked in motor domains. Numerous edges of this network strengthened in athletes were significantly weakened with concussion. Aligned to meta-analytic neuroimaging data, the observed changes suggest functional enhancement within the motor, sensory, coordination, balance, and visual processing domains in athletes, attenuated by concussive head injury with a negative impact on memory and language.
CONCLUSIONS
These findings suggest that engagement in sport may benefit the brain across numerous domains, but also highlights the potentially damaging effects of concussive head injury. Future studies with longitudinal cohorts including autopsy examination are needed to determine whether the latter reflects tissue loss from brain shearing, or the onset of a progressive Alzheimer's disease like proteinopathy.
PubMed: 38549627
DOI: 10.3233/ADR-240021 -
Life (Basel, Switzerland) Feb 2024The diagnostic value of the computer accommodation method remains insufficiently studied. Accommodative and refractive error is a common problem, accounting for 23% of...
The diagnostic value of the computer accommodation method remains insufficiently studied. Accommodative and refractive error is a common problem, accounting for 23% of the world's population. The aim of the study was to investigate the objective parameters of accommodative insufficiency in young people with and without myopia. A cross-sectional study was carried out using a random sample of 116 of university students at the age of 21-23 years. Normal ranges for accommodation parameters in non-myopic participants were defined by 10th and 90th percentile values. The normal ranges were from -0.17 to -0.38 conventional units (c.u.) for accommodative response coefficient (ARC), from 0.08 to 0.41 c.u. for deviation of ARC (σARC), from 0.0 to 0.43 c.u. for accommodogram growth coefficient (AGC), from 54.26 to 58.55 microfluctuations per minute (mcf/min) for coefficient of microfluctuations (CMF), and from 2.58 to 5.26 c.u. for deviation of CMF (σCMF). Signs of computer visual syndrome were observed in 40.9% of non-myopic participants, eye strain in 11.9%, accommodation cramp in 4.5%, and absence or little accommodative response in 3.6%. Therefore, computer accommodation assessment allowed the detection of young people with an increased risk of myopia among those without this ophthalmic pathology.
PubMed: 38541650
DOI: 10.3390/life14030324 -
Journal of Cataract and Refractive... Jun 2024
Topics: Humans; Lens Implantation, Intraocular; Incidence; Accommodation, Ocular; Lenses, Intraocular; Visual Acuity; Risk Factors; Phacoemulsification
PubMed: 38535978
DOI: 10.1097/j.jcrs.0000000000001450 -
Ophthalmic & Physiological Optics : the... Jul 2024Asthenopia is related to near vision activities or visual tasks that dissociate accommodation from vergence. Since the results of previous studies using objective...
PURPOSE
Asthenopia is related to near vision activities or visual tasks that dissociate accommodation from vergence. Since the results of previous studies using objective measures to diagnose asthenopia are inconsistent, this study compared optometric tests and objective metrics of accommodation in non-asthenopic and asthenopic young adults before and after a visual fatigue task.
METHODS
The accommodative response was recorded objectively for 6 min at a 3.33 D accommodative demand using an autorefractor, before and after a 5-min non-congruent visual task. Accommodation was disassociated from vergence with a ±2.00 D accommodative flipper while reading at the same distance. Optometric tests and subjective evaluations of asthenopia were performed before and after the task. Twenty-six non-presbyopic adults (23.15 ± 2.56 years) were included and identified as asthenopic (n = 14) or non-asthenopic (n = 12) based on their score on the Computer Vision Syndrome Questionnaire.
RESULTS
A mixed ANOVA found no significant difference between the groups for objective (accommodative response) or subjective metrics (feeling of fatigue, optometric tests), although all participants reported greater visual fatigue after the task. A significant effect of time (before and after the non-congruent task) was identified for the overall sample for mean accommodative lag (+0.10 D, p = 0.01), subjective visual fatigue (+1.18, p < 0.01), negative relative accommodation (-0.20 D, p = 0.02) and near negative fusional reserve (blur: +2.46Δ, p < 0.01; break: +1.89Δ, p < 0.01; recovery: +3.34Δ, p = 0.02).
CONCLUSIONS
The task-induced asthenopia, measured both objectively and subjectively, was accompanied by a change in accommodative lag, greater visual fatigue and a decrease in negative relative accommodation. Conversely, near negative fusional reserves seem to adapt to the task. No significant differences were found between the two groups with respect to accommodative metrics (objective) or subjective and optometric tests.
Topics: Humans; Accommodation, Ocular; Asthenopia; Male; Female; Young Adult; Adult; Visual Acuity; Refraction, Ocular; Surveys and Questionnaires; Convergence, Ocular
PubMed: 38533853
DOI: 10.1111/opo.13304 -
Medical Humanities Mar 2024Audio description improves access to visual culture for people who are unable to fully participate in it due to visual impairments. Because of this direct benefit to...
Audio description improves access to visual culture for people who are unable to fully participate in it due to visual impairments. Because of this direct benefit to disabled people, it is usually defined as an accommodation or inclusion service. Rather than adopting this view, we see disability as a creative force, arguing that it can engender a new dimension of art: audio description as a form of cinematic ekphrasis. This claim is made by drawing on the 2017 movie , by Japanese director Naomi Kawase. This movie puts audio description in the spotlight and stimulates discussion on this underdeveloped and under-recognised art. is structured around the process of making the audio description, thus offering good insight into the artistry and main challenges of this process. Between the words of this meditation on the art of audio description, Kawase also challenges the dominant ocular normative narrative on blindness as a deficiency and provokes a discussion on the contribution that blindness-with its different, still culturally unexplored modes of perception-could make to the interpretation of visual arts. can thus be treated as an artful argument for the greater recognition of disabled people's right to participate in cultural life.
PubMed: 38527798
DOI: 10.1136/medhum-2023-012802 -
Frontiers in Physiology 2024Optic nerve sheath diameter (ONSD) increases significantly at high altitudes, and is associated with the presence and severity of acute mountain sickness (AMS)....
Optic nerve sheath diameter (ONSD) increases significantly at high altitudes, and is associated with the presence and severity of acute mountain sickness (AMS). Exposure to hypobaria, hypoxia, and coldness when hiking also impacts intraocular pressure (IOP). To date, little is known about ocular physiological responses in trekkers with myopia at high altitudes. This study aimed to determine changes in the ONSD and IOP between participants with and without high myopia (HM) during hiking and to test whether these changes could predict symptoms of AMS. Nine participants with HM and 18 without HM participated in a 3-day trek of Xue Mountain. The ONSD, IOP, and questionnaires were examined before and during the trek of Xue Mountain. The ONSD values increased significantly in both HM ( = 0.005) and non-HM trekkers ( = 0.018) at an altitude of 1,700 m. In the HM group, IOP levels were greater than those in the non-HM group ( = 0.034) on the first day of trekking (altitude: 3,150 m). No statistically significant difference was observed between the two groups for the values of ONSD. Fractional changes in ONSD at an altitude of 1,700 m were related to the development of AMS ( = 0.448, = 0.019) and the presence of headache symptoms ( = 0.542, = 0.004). The area under the ROC curve for the diagnostic performance of ONSD fractional changes at an altitude of 1,700 m was 0.859 for predicting the development of AMS and 0.803 for predicting the presence of headache symptoms. Analysis of changes in ONSD at moderate altitude could predict AMS symptoms before an ascent to high altitude. Myopia may impact physiological accommodation at high altitudes, and HM trekkers potentially demonstrate suboptimal regulation of aqueous humor in such environments.
PubMed: 38523807
DOI: 10.3389/fphys.2024.1350051 -
Journal of Vision Mar 2024Accommodation is the process of adjusting the eye's optical power so as to focus at different distances. Uncorrected refractive error and/or functional presbyopia mean...
Accommodation is the process of adjusting the eye's optical power so as to focus at different distances. Uncorrected refractive error and/or functional presbyopia mean that sharp focus may not be achievable for some distances, so observers experience sustained defocus. Here, we identify a problem with current models of accommodative control: They predict excessive internal responses to stimuli outside accommodative range, leading to unrealistic adaptation effects. Specifically, after prolonged exposure to stimuli outside range, current models predict long latencies in the accommodative response to stimuli within range, as well as unrealistic dynamics and amplitudes of accommodative vergence innervation driven by the accommodative neural controller. These behaviors are not observed empirically. To solve this issue, we propose that the input to blur-driven accommodation is not retinal defocus, but correctable defocus. Predictive models of accommodative control already estimate demand from sensed defocus, using a realistic "virtual plant" to estimate accommodation. Correctable defocus can be obtained by restricting this demand to values physically attainable by the eye. If we further postulate that correctable defocus is computed using an idealized virtual plant that retains a young accommodative range, we can explain why accommodative-convergence responses are observed for stimuli that are too near-but not too far-to focus on. We model cycloplegia as a change in gain, and postulate a form of neural myopia to explain the additional relaxation of accommodation often seen with cycloplegia. This model produces plausible predictions for the accommodative response and accommodative convergence signal in a wide range of clinically relevant situations.
Topics: Humans; Presbyopia; Refractive Errors; Accommodation, Ocular; Myopia; Retina
PubMed: 38488409
DOI: 10.1167/jov.24.3.4 -
Journal of Optometry Mar 2024Many sports-related concussion (SRC) outcomes can be prevented by removing affected athletes and allowing return after full recovery. Diagnosing concussions on the...
PURPOSE
Many sports-related concussion (SRC) outcomes can be prevented by removing affected athletes and allowing return after full recovery. Diagnosing concussions on the side-line is challenging, as tools often rely on visual performance assessment. Since acute exercise can affect vision, it is vital to determine if exercise can mask potential brain injury if visual performance assessments are used. The aim of this study was to determine the effect of a single bout of maximal aerobic exercise on acute visual performance.
METHODS
Eighty previously sedentary females were randomly assigned to an experimental group (N = 40) or control group (N = 40) and completed an identical visual task test battery. Two weeks later, participants returned to participate in the test battery, with the experimental group doing so immediately following a maximal treadmill exercise protocol.
RESULTS
Significant (P < 0.05) improvements were found in accommodation facility, saccadic eye movement, speed of recognition, peripheral awareness, and hand-eye coordination (P < 0.001 for all), but not in visual memory (P = 0.556). All visual tasks, barring visual memory, loaded onto a single factor and approximated the root mean square error of approximation (RMSEA) threshold value (RMSEA = 0.112 [90 %CI: 0.047-0.182]), and a significant large main effect was found on all factors as a universal visual task performance (P < 0.001; d = 1.01).
CONCLUSION
This study shows that exercise can affect performance across multiple, but not all, visual tasks and should be utilised with caution in comprehensive side-line SRC assessments. Visual memory may be more stable to the effects of acute exercise and be considered for inclusion in side-line SRC assessments.
PubMed: 38479117
DOI: 10.1016/j.optom.2024.100515 -
Scientific Reports Mar 2024How the human eye focuses for near; i.e. accommodates, is still being evaluated after more than 165 years. The mechanism of accommodation is essential for understanding...
How the human eye focuses for near; i.e. accommodates, is still being evaluated after more than 165 years. The mechanism of accommodation is essential for understanding the etiology and potential treatments for myopia, glaucoma and presbyopia. Presbyopia affects 100% of the population in the fifth decade of life. The lens is encased in a semi-elastic capsule with attached ligaments called zonules that mediate ciliary muscle forces to alter lens shape. The zonules are attached at the lens capsule equator. The fundamental issue is whether during accommodation all the zonules relax causing the central and peripheral lens surfaces to steepen, or the equatorial zonules are under increased tension while the anterior and posterior zonules relax causing the lens surface to peripherally flatten and centrally steepen while maintaining lens stability. Here we show with a balloon capsule zonular force model that increased equatorial zonular tension with relaxation of the anterior and posterior zonules replicates the topographical changes observed during in vivo rhesus and human accommodation of the lens capsule without lens stroma. The zonular forces required to simulate lens capsule configuration during in vivo accommodation are inconsistent with the general belief that all the zonules relax during accommodation.
Topics: Animals; Humans; Presbyopia; Lens Capsule, Crystalline; Accommodation, Ocular; Lens, Crystalline; Macaca mulatta
PubMed: 38467700
DOI: 10.1038/s41598-024-56563-8