Impact of accommodative insufficiency and accommodative/vergence therapy on ciliary muscle thickness in the eye.

PURPOSE: Recent evidence suggests that the ciliary muscle apical fibres are most responsive to accommodative load; however, the structure of the ciliary muscle in individuals with accommodative insufficiency is unknown. This study examined ciliary muscle structure in individuals with accommodative insufficiency (AI). We also determined the response of the ciliary muscle to accommodative/vergence therapy and increasing accommodative demands to investigate the muscle's responsiveness to workload. METHODS: Subjects with AI were enrolled and matched by age and refractive error with subjects enrolled in another ciliary muscle study as controls. Anterior segment optical coherence tomography was used to measure the ciliary muscle thickness (CMT) at rest (0D), maximum thickness (CMTMAX) and over the area from 0.75 mm (CMT0.75) to 3 mm (CMT3) posterior to the scleral spur of the right eye. For those with AI, the ciliary muscle was also measured at increasing levels of accommodative demand (2D, 4D and 6D), both before and after accommodative/vergence therapy. RESULTS: Sixteen subjects with AI (mean age = 17.4 years, SD = 8.0) were matched with 48 controls (mean age = 17.8 years, SD = 8.2). On average, the controls had 52-72 µm thicker ciliary muscles in the apical region at 0D than those with AI (p = 0.03 for both CMTMAX and CMT 0.75). Differences in thickness between the groups in other regions of the muscle were not statistically significant. After 8 weeks of accommodative/vergence therapy, the CMT increased by an average of 22-42 µm (p ≤ 0.04 for all), while AA increased by 7D (p < 0.001). CONCLUSIONS: This study demonstrated significantly thinner apical ciliary muscle thickness in those with AI and that the ciliary muscle can thicken in response to increased workload. This may explain the mechanism for improvement in signs and symptoms with accommodative/vergence therapy.

Asymptomatic retinal emboli and current practice guidelines: a review.

Asymptomatic retinal emboli are found in 1-3% of patients on routine fundus examination. As the use of teleretinal imaging for diabetic patients and ocular photography continues to increase, the number of asymptomatic retinal emboli found will also increase. This article will discuss the different aetiologies of retinal emboli and will present an overview of the recommended referrals for further systemic testing and treatment. It is important to communicate well with the primary care physician when asymptomatic retinal emboli are detected to ensure the appropriate investigations are undertaken.

The effects of subacute exposure to a water-soluble cannabinol compound in male mice.

BACKGROUND: Cannabinol (CBN) is one of the many cannabinoids present in Cannabis sativa and has been explored as a potential treatment for sleeplessness. The purpose of this study was to determine the physiological and behavioral effects of subacute exposure to therapeutic and low pharmacological levels of a mechanically formed, stabilized water-soluble cannabinol nano-emulsion (CBNight™). METHODS: Sixty-two male mice were randomly assigned to one of six treatment groups given CBNight™ at dosages designed to deliver 0mg (control) to 4 mg/kg of CBN daily via oral gavage for 14 days. In-cage behavior was observed at 30 minutes and at 2, 4, 8, and 16 hours after each dose. After 14 days, the mice were sacrificed and necropsied. Organs were weighed and inspected for gross abnormalities, and blood was collected via cardiac puncture for clinical chemistry. RESULTS: No dosage-dependent adverse effects on behavior, body mass, or blood chemistry were observed, except that the highest doses of CBNight™ were associated with significantly lower eosinophil counts. CONCLUSIONS: The commercially available, water-soluble CBN compound employed in this study does not appear to cause adverse effects in mice; rather, it appears to be well tolerated at pharmacological levels. The findings of eosinopenia at higher doses of CBN and lack of hepatotoxicity at any dosage employed in this study have not been reported to date.

Ciliary muscle thickness in adults with Down syndrome.

PURPOSE: The relationship between ciliary muscle thickness (CMT), age and refractive error was investigated to determine if CMT, like other anterior ocular anatomy, differs in adults with Down syndrome (DS). METHODS: The CMT of 33 adults with DS was imaged using anterior segment optical coherence tomography. Images from the right eye obtained 45 minutes after cycloplegia (1% tropicamide, 2.5% phenylephrine) were analysed to calculate thickness at 1, 2 and 3 mm posterior to the scleral spur (CMT1, CMT2, CMT3), maximum thickness (CMTMAX) and apical thickness (AT = CMT1 - CMT2). Spherical equivalent refractive error was determined by clinical refraction using both non-dilated and dilated measures. Multivariate regression analysis evaluated the relationship between CMT and refractive error while controlling for subject age. RESULTS: Images were analysed from 26 subjects (mean age (SD) 29 years; mean refractive error (SD): -0.90 (5.03) D, range: -15.75 to +5.13D). Mean (SD) CMT decreased with posterior position (CMT1: 804 (83) µm; CMT2: 543 (131) µm; CMT3: 312 (100) µm). Mean (SD) CMTMAX and AT was 869 (57) µm and 260 (84) µm, respectively. There was a significant linear correlation indicating thinning CMT with increasing age for CMT1 and CMT2 (p ≤0.05). CMT2 and CMT3 had a significant negative correlation (thicker muscle with increasing myopic refractive error) (p ≤0.01). AT had a significant positive correlation (thicker muscle with increasing hyperopic refractive error) (p <0.01). CONCLUSIONS: Ciliary muscle thickness in participants with DS was found to be in a similar range with similar refractive error trends to previous reports of individuals without DS. However, it is important to note that the refractive error trends were driven by individuals with moderate to high levels of myopia.

A randomised clinical trial of multifocal contact lenses and contact lens discomfort.

PURPOSE: To determine how multifocal contact lenses affect contact lens discomfort. METHODS: This randomised, participant-masked, crossover clinical trial fitted 84 uncomfortable soft contact lens wearers (30-40 years old) with single vision and multifocal contact lenses. Contact lens discomfort was assessed using the Contact Lens Dry Eye Questionnaire-8 (CLDEQ-8). RESULTS: There was no difference between multifocal and single vision survey scores (p = 0.08). There was an interaction between lens type and age group (p = 0.05). CLDEQ-8 scores with the single vision lens were less symptomatic than multifocal scores in participants <35 years old (p = 0.01). Single vision and multifocal scores for the older age group were not different. Subjectively, those in the <35 year-old age group preferred the single vision lens for intermediate (p = 0.02), distance (p = 0.003), and overall vision (p = 0.002). In the ≥35 year-old age group, no lens was significantly preferred for vision. CONCLUSIONS: Participants in the younger age group had more favourable wearing experiences with the single vision lens compared to the multifocal lens. The older age group, however, had similar wearing experiences with both lens types. While younger contact lens wearers may prefer the wearing experience with single vision lenses, some uncomfortable contact lens wearers approaching 40 years old may benefit from wearing a multifocal contact lens sooner in life than is typically practised.

A Culinary Medicine Elective for Clinically Experienced Medical Students: A Pilot Study.

Purpose: Culinary medicine, a combination of nutrition science and the culinary arts, is an emerging approach for teaching nutrition to medical students and improving their competence in counseling patients with diet-associated diseases. Data are, however, lacking on the impact of culinary medicine courses directed at clinically experienced students. This study reports initial outcomes of a pilot nutrition and culinary medicine course targeting 4th-year medical students. Methods: An elective course on culinary medicine was offered to 4th-year medical students at the Perelman School of Medicine, comprising seven disease-focused sessions, with a final capstone session. Students read primary literature for each session. Individual sessions consisted of culinary literacy, cooking, and a case discussion led by physicians and registered dietitians. In addition, students participated in a nutrition education initiative in a local high school. Students completed pre-and postcourse surveys that evaluated perceived nutrition knowledge and counseling skills and personal dietary choices, and included free-text options for qualitative comments. Results: Thirty-one 4th-year medical students participated in three offerings of the course in 2018 and 2019. There was strong student enthusiasm for the course as (1) all the available slots for each course offering were filled within 2 h of an e-mail announcement to the students; (2) student attendance was consistently very high; and (3) student feedback about the course was uniformly positive. Students reported significant increases in their confidence regarding (1) knowledge of pertinent nutrition information; (2) discussing nutrition with patients; and (3) ability to impact patient behavior through counseling (p < 0.001). Qualitative comments suggested that students were contemplating or implementing changes in their dietary habits and food choices. Conclusion: A culinary medicine course for clinically experienced medical students may improve perceived nutrition knowledge and increases confidence in counseling patients with diet-associated diseases.

A study of contact lens compliance in a non-clinical setting.

PURPOSE: To evaluate soft contact lens replacement, overnight (ON) wear, and contact lens case compliance in a non-clinical sample. METHODS: Subjects (n = 297) were recruited at the Center for Science and Industry (COSI) in Columbus, Ohio. Adult (≥ 18 years) soft contact lens wearers completed a survey about contact lens replacement, ON contact lens wear, and contact lens case replacement habits. RESULTS: Two-week replacement lenses (according to the manufacturer's replacement schedule [MRS]) were most common (45.5%), followed by monthly (34.3%) and daily replacement (20.2%). Non-compliance with replacement schedule was reported in 38.7% of subjects. Age (p = 0.02), years of lens wear (p = 0.02), and MRS (p <0.0001) affected replacement compliance. Post-hoc analysis showed daily replacement wearers were more compliant than two-week (p <0.0001) and monthly (p <0.0001) replacement wearers with prescribed lens replacement. Non-compliance with prescribed ON wear was reported in 23.9% of subjects. Subjects who were non-compliant with lens replacement were more likely to be non-compliant with ON wear (p = 0.02) and had worn contact lenses for less time (p = 0.02). Of the subjects who used contact lens cases, 74.6% were unsure when they should replace their case. Frequency of case replacement was not associated with age (p = 0.5), gender (p = 0.5), years of contact lens wear (p = 0.7), MRS (p = 0.4), replacement compliance (p = 0.3), or ON wear compliance (p = 0.7). CONCLUSIONS: Daily replacement wearers were most likely to be compliant with contact lens replacement, but all subjects, including daily replacement wearers, had similar ON wear non-compliance. Non-compliant lens replacement was associated with non-compliant ON wear, but contact lens case replacement was not related to either compliance category. The majority of subjects had no knowledge of proper contact lens case replacement, despite compliance in other categories.

Parametric study on the production of the GAGG:Ce and LSO:Ce multicomponent oxide scintillator materials through use of a planetary ball mill.

The material presented herein focuses on the exploration of the production of gadolinium aluminum gallium garnet and lutetium oxyorthosilicate doped with cerium (GAGG:Ce and LSO:Ce, respectively) through mechanochemical means. Multiple parameters are explored including mass of starting material, ball size, rotational speed of the mill, number of balls employed, and material used for the milling container. Theoretical calculations were conducted using a pre-established equation and showed that, when all other parameters were held constant, in scenarios where (1) a smaller mass of sample, (2) faster revolutions per minute, (3) greater numbers of balls, or (4) a greater density of the material used for the vials and balls were employed, there should be higher energies imparted to the system. Actual results executed appeared to exhibit somewhat congruent results, but showed limitations due to experimental (non-idealized) conditions.

Relationship of Adverse Family Experiences to Resilience and School Engagement Among Vermont Youth.

INTRODUCTION: Adverse childhood experiences (ACEs) are associated with a range of health outcomes and risk behaviors. In 2011-2012, the National Survey of Children's Health (NSCH) included questions about adverse family experiences (AFEs). AFE survey questions are similar to ACE questions, except there are no questions about emotional/physical/sexual trauma, and questions are asked of parents rather than children. Although the relationship between ACEs and work/school absenteeism has been studied, the relationships between AFEs of school-aged children, school performance, and buffering behaviors have not been explored in depth. METHODS: We examined AFEs and measures of resilience and school engagement among 1330 Vermont children (6-17 years) included in the NSCH, using descriptive, bivariate, and multivariable analyses. RESULTS: The most prevalent AFEs were divorce/separation of parents; family income hardship; substance use problems; and mental illness, suicidality, or severe depression. Adjusting for sex, age, special health care needs, poverty level, and maternal physical/mental-emotional health status, children who had three or more AFEs had lower odds of completing all required homework [adjusted odds ratio (AOR) 3.3, 95% confidence interval (CI) 1.7-6.3] and higher odds of failing to exhibit resilience (AOR 2.1, 95% CI 1.2-3.8), compared to children having no AFEs. DISCUSSION: Children with three or more AFEs had difficulty engaging in school and completing homework, though poor outcomes were buffered when children showed resilience. Parents, school-based mental health professionals, and teachers could help identify children who may be less resilient and have difficulties completing homework assignments. Preventive approaches to children's emotional problems (e.g., promoting family health, using family-based approaches to treat emotional/behavioral problems) could be applied in schools and communities to foster resilience and improve school engagement of children.

[Cr3O(O2CCH2CH3)6(H2O)3]NO3·H2O (Cr3) Toxicity Potential in Bacterial and Mammalian Cells.

Chromium(III) has generally been considered to be essential for proper carbohydrate and lipid metabolism, and, despite recent evidence to the contrary, chromium(III)-containing compounds remain one of the most popular commercial dietary supplements. Cr3, or [Cr3O(O2CCH2CH3)6(H2O)3]NO3·H2O, is a trivalent chromium compound that is a promising chromium nutritional supplement. Studies with Cr3 have indicated that it is non-toxic in developmental and short- and long-term exposure studies in rodents, but the safety of this compound to chromosomes and cells has not been explored. The current study evaluates the mutagenicity, cytotoxicity, and clastogenicity of Cr3 in bacterial and mammalian cells and compares these results with similar studies using the bestselling Cr(III) nutritional supplement, chromium picolinate (CrPic). The mutagenicity of CrPic and Cr3 was tested in Escherichia coli FX-11 and Salmonella typhimurium (TA 98 and TA 100). Cytotoxicity was measured as a decrease in plating efficiency relative to controls after treatment with Cr3 and CrPic for 24 h in CHO K1 cells. Clastogenicity was measured by counting the number of metaphases damaged and of the total number chromosomal aberrations in CHO K1 cells. Mutagenesis assays in E. coli and S. typhimurium were negative. All treatments of Cr3 produced ≥ 84% plating efficiency except 80 µg/cm2, which reduced the plating efficiency to 62%. Cr3 at any treatment level did not produce a significant increase in the number of cells with abnormal metaphases, while treatments using ≥ 40 µg/cm2 of CrPic elevated the number significantly. These data suggest that Cr3 is significantly less mutagenic in bacteria cells and less clastogenic in CHO K1 cells, while CrPic is clastogenic in CHO K1 cells.

Exposure to the Dietary Supplement N-Acetyl-L-Cysteine during Pregnancy Reduces Cyclophosphamide Teratogenesis in ICR Mice.

Cyclophosphamide (CP) is a complex multifaceted developmental toxicant, with mechanisms of teratogenesis thought to include production of excessive reactive oxygen species (ROS). N-acetyl-L-cysteine (NAC) is a powerful antioxidant that may decrease the toxicity of certain anticancer drugs, such as doxorubicin and CP. The current study explored the potential of NAC to attenuate CP-induced damage to the conceptus. Mated ICR mice were orally dosed with 150 mg/kg/d NAC, 150 mg/kg/d NAC + 20 mg/kg CP, CP only, or vehicle only. CP was administered by intraperitoneal injection on gestation day (GD) 10, and NAC was given by gavage on gestation days 6-13. Dams were sacrificed on GD 17, and their litters were examined for adverse effects. There were significant reductions in the incidences of digit, limb, and tail defects, as well as anasarca and macroglossia, in fetuses exposed to the combination of NAC and CP, compared to fetuses exposed to CP only. NAC did not increase the incidence of any defects when compared to control. Fetuses exposed to NAC weighed significantly more than the average vehicle control fetus. The data indicate that NAC, a well-tolerated, relatively inexpensive antioxidant, appears to reduce the incidence of specific cyclophosphamide-induced malformations when administered prior to, concurrently with, and after exposure to CP.

Presbyopic and non-presbyopic contact lens opinions and vision correction preferences.

PURPOSE: To compare vision correction preferences, refractive error, and gender of non-presbyopes and presbyopes. METHODS: Adults who wear spectacles or contact lenses completed a survey about refractive correction opinions and refractive error was measured. RESULTS: Of the 304 subjects, 38.2% were presbyopic (≥40 years) and 59.2% were female. Spectacles were the primary vision correction for 78.0% of subjects. Compared to contact lens wearers, the proportion of presbyopes was higher (p=0.006) in spectacle wearers. There was no difference in the proportion of presbyopes and non-presbyopes who have tried contact lenses (p=0.2) or who would prefer to wear contact lenses (p=0.2). In contact lens wearers, there was no difference in the proportion of presbyopes and non-presbyopes with a history of temporary discontinuation (p=0.9). Within the contact lens wearing group, there was no refractive error difference between presbyopes and non-presbyopes (spherical equivalent p=0.6; power vector J0 p=0.5; power vector J45 p=0.4; anisometropia p=0.2). Overall, contact lens wearers were more likely to be female (p=0.004). There was no difference in gender in presbyopic and non-presbyopic contact lens wearers (p=0.5). CONCLUSIONS: Presbyopes and non-presbyopes have similar opinions about spectacles and contact lenses. Presbyopes of all refractive errors prefer contact lens correction when good vision and comfort can be achieved. Eye care providers should not assume that presbyopia, refractive error, or gender are factors that preclude a patient from being interested in contact lens wear.

Reduced haemodynamic coupling and exercise are associated with vascular stiffening in pulmonary arterial hypertension.

OBJECTIVE: Inadequate right ventricular (RV) and pulmonary arterial (PA) functional responses to exercise are important yet poorly understood features of pulmonary arterial hypertension (PAH). This study combined invasive catheterisation with echocardiography to assess RV afterload, RV function and ventricular-vascular coupling in subjects with PAH. METHODS: Twenty-six subjects with PAH were prospectively recruited to undergo right heart catheterisation and Doppler echocardiography at rest and during incremental exercise, and cardiac MRI at rest. Measurements at rest included basic haemodynamics, RV function and coupling efficiency (η). Measurements during incremental exercise included pulmonary vascular resistance (Z0), characteristic impedance (ZC, a measure of proximal PA stiffness) and proximal and distal PA compliance (CPA). RESULTS: In patients with PAH, the proximal PAs were significantly stiffer at maximum exercise (ZC =2.31±0.38 vs 1.33±0.15 WU×m2 at rest; p=0.003) and PA compliance was decreased (CPA=0.88±0.10 vs 1.32±0.17 mL/mm Hg/m2 at rest; p=0.0002). Z0 did not change with exercise. As a result, the resistance-compliance (RC) time decreased with exercise (0.67±0.05 vs 1.00±0.07 s at rest; p<10-6). When patients were grouped according to resting coupling efficiency, those with poorer η exhibited stiffer proximal PAs at rest, a lower maximum exercise level, and more limited CPA reduction at maximum exercise. CONCLUSIONS: In PAH, exercise causes proximal and distal PA stiffening, which combined with preserved Z0 results in decreased RC time with exercise. Stiff PAs at rest may also contribute to poor haemodynamic coupling, reflecting reduced pulmonary vascular reserve that contributes to limit the maximum exercise level tolerated.

Normal radial migration and lamination are maintained in dyslexia-susceptibility candidate gene homolog Kiaa0319 knockout mice.

Developmental dyslexia is a common disorder with a strong genetic component, but the underlying molecular mechanisms are still unknown. Several candidate dyslexia-susceptibility genes, including KIAA0319, DYX1C1, and DCDC2, have been identified in humans. RNA interference experiments targeting these genes in rat embryos have shown impairments in neuronal migration, suggesting that defects in radial cortical migration could be involved in the disease mechanism of dyslexia. Here we present the first characterisation of a Kiaa0319 knockout mouse line. Animals lacking KIAA0319 protein do not show anatomical abnormalities in any of the layered structures of the brain. Neurogenesis and radial migration of cortical projection neurons are not altered, and the intrinsic electrophysiological properties of Kiaa0319-deficient neurons do not differ from those of wild-type neurons. Kiaa0319 overexpression in cortex delays radial migration, but does not affect final neuronal position. However, knockout animals show subtle differences suggesting possible alterations in anxiety-related behaviour and in sensorimotor gating. Our results do not reveal a migration disorder in the mouse model, adding to the body of evidence available for Dcdc2 and Dyx1c1 that, unlike in the rat in utero knockdown models, the dyslexia-susceptibility candidate mouse homolog genes do not play an evident role in neuronal migration. However, KIAA0319 protein expression seems to be restricted to the brain, not only in early developmental stages but also in adult mice, indicative of a role of this protein in brain function. The constitutive and conditional knockout lines reported here will be useful tools for further functional analyses of Kiaa0319.

A Survey of Presbyopic Contact Lens Wearers in a University Setting.

PURPOSE: To determine why presbyopic patients discontinue contact lens wear and describe their opinions of comfort and visual quality with contact lenses. METHODS: A survey assessing current age, gender, contact lens material/design, and opinions of contact lens comfort and visual quality was mailed to 2400 presbyopic patients (age 40 years and older) that have had eye exams in the Ohio State University College of Optometry's Contact Lens Services over the last 4 years. RESULTS: A total of 496 surveys were analyzed. The mean age of survey respondents was 57 ± 9 years, and 68% of the sample was female. Permanent discontinuation of contact lens wear was reported by 15%. No association was found between contact lens discontinuation and age (p = 0.7), gender (p = 0.2), age of beginning contact lens wear (p = 0.1), or contact lens material (p = 0.1). Poor vision (38%), discomfort (34%), convenience (20%), and cost (6%) were the primary reported reasons for discontinuation. There was no difference between the proportion of subjects reporting "poor vision" as their primary discontinuation reason and those reporting "discomfort" (p = 0.7). Discontinued wearers had a worse overall opinion of their distance (p = 0.03), intermediate (p = 0.01), and near vision (p = 0.002) compared to subjects who were still wearing their contact lenses. CONCLUSIONS: Discomfort has been reported as the primary reason for contact lens discontinuation. In this presbyopic population, dissatisfaction with vision and discomfort were reported equally as often as primary reasons for discontinuation. As well, subjects who ceased contact lens wear had worse overall opinions of their vision at all distances than current contact lens wearers. The results of this survey suggest that presbyopes have unique demands and opinions related to contact lens wear.

Can Binocular Vision Disorders Contribute to Contact Lens Discomfort?

PURPOSE: To determine the relationship between binocular vision (BV) disorder and dry eye symptoms and the frequency of BV disorders in subjects with contact lens-induced dry eye symptoms. METHODS: Subjects recruited for a larger dry eye study (n = 104) completed the Ocular Surface Disease Index (OSDI) and Convergence Insufficiency Symptom Survey (CISS) to determine if symptoms assessed on these two surveys were related. Also, myopic soft contact lens wearers (n = 29) with self-reported dry eye symptoms were recruited. Subjects completed the OSDI and CISS to assess severity of dry eye and BV disorder symptoms. Basic BV and dry eye testing was performed on each subject. RESULTS: Severity of symptoms assessed on the OSDI and CISS was found to be significantly correlated in the larger subject group (ρ = 0.68, p = 0.0001). This significant correlation warranted further investigation of both symptoms and clinical signs. In the group of myopic soft contact lens wearers, 48.3% had a BV disorder. This proportion appeared to be higher than previously reported prevalence estimates of BV disorders. Accommodative lag greater than or equal to 1.00 diopter was the most common BV disorder sign encountered (48.3%), and pseudo-convergence insufficiency was the most common BV disorder (31.0%). CONCLUSIONS: Symptoms related to dry eye and BV disorders overlap. Subjects with symptoms of discomfort while wearing soft contact lenses may be experiencing a concurrent or stand-alone BV disorder. Accommodative insufficiency and pseudo-convergence insufficiency were common in the sample of myopic soft contact lens wearers. Clinicians should screen symptomatic contact lens-induced dry eye patients for BV disorders. Dry eye studies should assess basic BV function.

Ciliary muscle thickness in anisometropia.

PURPOSE: The purpose of this study was to investigate the relationships between ciliary muscle thickness (CMT), refractive error, and axial length both across subjects and between the more and less myopic eyes of adults with anisometropia. METHODS: Both eyes of 29 adult subjects with at least 1.00 D of anisometropia were measured. Ciliary muscle thickness was measured at the maximum thickness (CMTMAX) and at 1.0 (CMT1), 2.0 (CMT2), and 3.0 mm (CMT3) posterior to the scleral spur, and also at the apical region (Apical CMTMAX = CMTMAX - CMT2, and Apical CMT1 = CMT1 - CMT2). Multilevel regression models were used to determine the relationship between the various CMT measures and cycloplegic refractive error or axial length, and to assess whether there are CMT differences between the more and less myopic eyes of an anisometropic adult. RESULTS: CMTMAX, CMT1, CMT2, and CMT3 were negatively associated with mean refractive error (all p ≤ 0.03), and the strongest association was in the posterior region (CMT2 and CMT3). Apical CMTMAX and Apical CMT1, however, were positively associated with mean refractive error (both p < 0.0001) across subjects. Within a subject, i.e., comparing the two anisometropic eyes, there was no statistically significant difference in CMT in any region. CONCLUSIONS: Similar to previous studies, across anisometropic subjects, a thicker posterior region of the ciliary muscle (CMT2 and CMT3) was associated with increased myopic refractive error. Conversely, shorter, more hyperopic eyes tended to have thicker anterior, apical fiber portions of their ciliary muscle (Apical CMTMAX and Apical CMT1). There was no difference between the two eyes for any CMT measurement, indicating that in anisometropia, an eye can grow longer and more myopic than its fellow eye without resulting in an increase in CMT.

Four characteristics and a model of an effective tear film lipid layer (TFLL).

It is proposed that a normal, effective tear film lipid layer (TFLL) should have the following four characteristics: 1) high evaporation resistance to prevent water loss and consequent hyperosmolarity; 2) respreadability, so it will return to its original state after the compression-expansion cycle of the blink; 3) fluidity sufficient to avoid blocking secretion from meibomian glands; 4) gel-like and incompressible structure that can resist forces that may tend to disrupt it. These characteristics tend to be incompatible; for example, lipids that form good evaporation barriers tend to be disrupted by compression-expansion cycles. It is noted that clues about the function and organization of the TFLL can be obtained by comparison with other biological lipid layers, such as lung surfactant and the lipid evaporation barrier of the skin. In an attempt to satisfy the conflicting characteristics, a "multilamellar sandwich model" of the TFLL is proposed, having features in common with the skin evaporation barrier.

Region-specific relationships between refractive error and ciliary muscle thickness in children.

PURPOSE: To determine if there is a relationship between refractive error and ciliary muscle thickness in different muscle regions. METHODS: An anterior segment optical coherence tomographer was used to measure cycloplegic ciliary muscle thicknesses at 1 mm (CMT1), 2 mm (CMT2), and 3 mm (CMT3) posterior to the scleral spur; maximum (CMTMAX) thickness was also assessed. An autorefractor was used to determine cycloplegic spherical equivalent refractive error (SPHEQ). Apical ciliary muscle fibers were obtained by subtracting corresponding CMT2 values from CMT1 and CMTMAX. Multilevel regression models were used to determine the relationship between ciliary muscle thickness in various regions of the muscle and refractive error. RESULTS: Subjects included 269 children with a mean age of 8.71 ± 1.51 years and a mean refractive error of +0.41 ± 1.29 diopters. In linear models with ciliary muscle thicknesses and SPHEQ, SPHEQ was significantly associated only with CMT2 (ß = -11.34, P = 0.0008) and CMT 3 (ß = -6.97, P = 0.007). When corresponding values of CMT2 were subtracted from CMT1 and CMTMAX, apical fibers at CMT1 (ß = 14.75, P < 0.0001) and CMTMAX (ß = 18.16, P < 0.0001) had a significant relationship with SPHEQ. CONCLUSIONS: These data indicated that in children the posterior ciliary muscle fibers are thicker in myopia (CMT2 and CMT3), but paradoxically, the apical ciliary muscle fibers are thicker in hyperopia (CMTMAX and CMT1). This may be the first evidence that hyperopia is associated with a thicker apical ciliary muscle region.

Dynamic expression of MEIS1 homeoprotein in E14.5 forebrain and differentiated forebrain-derived neural stem cells.

Central nervous system development is controlled by highly conserved homeoprotein transcription factors including HOX and TALE (Three Amino acid Loop Extension). TALE proteins are primarily known as HOX-cofactors and play key roles in cell proliferation, differentiation and organogenesis. MEIS1 is a TALE member with established expression in the developing central nervous system. MEIS1 is essential for embryonic development and Meis1 knockout mice dies at embryonic day (E) 14.5. However, Meis1/MEIS1 expression in the devolving forebrain, at this critical time-point has not been studied. Here, for the first time we characterize the region-specific expression of MEIS1 in E14.5 mouse forebrain, filling the gap of MEIS1 expression profile between E12.5 and E16.5. Previously, we reported MEIS1 transcriptional regulatory role in neuronal differentiation and established forebrain-derived neural stem cells (NSC) for gene therapy application of neuronal genes. Here, we show the dynamic expression of Meis1/MEIS1 during the differentiation of forebrain-derived NSC toward a glial lineage. Our results show that Meis1/MEIS1 expression is induced during NSC differentiation and is expressed in both differentiated neurons and astrocytes. Confirming these results, we detected MEIS1 expression in primary cultures of in vivo differentiated cortical neurons and astrocytes. We further demonstrate Meis1/MEIS1 expression relative to other TALE family members in the forebrain-derived NSC in the absence of Hox genes. Our data provide evidence that forebrain-derived NSC can be used as an accessible in vitro model to study the expression and function of TALE proteins, supporting their potential role in modulating NSC self-renewal and differentiation.