Building on the literature on managerial myopia, we investigate how chief executive officers’ (CEOs) international experience in advanced market economies affects their firms' investment horizons in a transitioning economy. To overcome myopia, CEOs should possess the knowledge needed to manage current tasks, thereby freeing up cognitive resources for future considerations. In the context of our theorizing, we argue that international experience in advanced market economies equips CEOs with knowledge about how to deal with their current tasks of market-oriented adaptation in a transitioning economy, freeing up cognitive resources for considering longer-term investment horizons. Additionally, the effect of CEO international experience in advanced market economies on firm investment horizon is stronger under conditions that increase the cognitive burden on CEOs to perform market-oriented adaptation tasks – specifically, when there is a high scope of pro-market reform, high intensity of foreign competition, analyst coverage, and a high level of institutional ownership. Our estimation based on a matched sample of 204 Chinese CEOs during the period 2002–2019 supports the majority of our predictions. Our study contributes to research on firm investment horizon, CEO international experience, and transition economies.

Astigmatism and myopia are two common ocular refractive errors that can impact daily life, including learning and productivity. Current knowledge suggests that the etiology of these conditions is the result of a complex interplay between genetic and environmental factors. Studies in populations of European ancestry have demonstrated a higher concordance of refractive errors in monozygotic (MZ) twins compared to dizygotic (DZ) twins. However, there is a lack of studies on genetically informative samples of multi-ethnic ancestry. This study aimed to estimate the genetic contribution to astigmatism and myopia in the Mexican population. A sample of 1399 families, including 243 twin pairs and 1156 single twins, completed a medical questionnaire about their own and their co-twin’s diagnosis of astigmatism and myopia. Concordance rates for astigmatism and myopia were estimated, and heritability and genetic correlations were determined using a bivariate ACE Cholesky decomposition method, decomposed into A (additive genetic), C (shared environmental) and E (unique environmental) components. The results showed a higher concordance rate for astigmatism and myopia for MZ twins (.74 and .74, respectively) than for DZ twins (.50 and .55). The AE model, instead of the ACE model, best fitted the data. Based on this, heritability estimates were .81 for astigmatism and .81 for myopia, with a cross-trait genetic correlation of rA = .80, nonshared environmental correlation rE = .89, and a phenotypic correlation of rP = .80. These results are consistent with previous findings in other populations, providing evidence for a similar genetic architecture of these conditions in the multi-ethnic Mexican population.

Our previous research showed that increased phosphorylation of connexin (Cx)36 indicated extended  coupling of AII amacrine cells (ACs) in the rod-dominant mouse myopic retina. This research will determine whether phosphorylation at serine 276 of Cx35-containing gap junctions increased in the myopic chicken, whose retina is cone-dominant. Refractive errors and ocular biometric dimensions of 7-days-old chickens were determined following 12 h and 7 days induction of myopia by a −10D lens. The expression pattern and size of Cx35-positive plaques were examined in the early (12 h) and compensated stages (7 days) of lens-induced myopia (LIM). At the same time, phosphorylation at serine 276 (functional assay) of Cx35 in strata 5 (S5) of the inner plexiform layer was investigated. The axial length of the 7 days LIM eyes was significantly longer than that of non-LIM controls (P < 0.05). Anti-phospho-Ser276 (Ser276-P)-labeled plaques were significantly increased in LIM retinas at both 12 h and 7 days. The density of Ser276-P of Cx35 was observed to increase after 12 h LIM. In the meanwhile, the areas of existing Cx35 plaques did not change. As there was more phosphorylation of connexin35 at Ser276 at both the early and late stages (12 h) and 7 days of LIM chicken retinal activity, the coupling with ACs could be increased in myopia development of the cone-dominated chicken retina.

Nearly 80% of new cases of myopia arise between 9 and 13 years old when puberty development also progresses rapidly. However, little is known about the association between myopia and puberty. We aim to evaluate the association between myopia and menarche, the most important puberty indicator for girls, and to test whether menarche could modify the effects of myopia-related behaviors. The participants came from two consecutive national surveys conducted in 30 provinces in mainland China in 2010 and 2014. We included 102,883 girls (61% had experienced menarche) aged 10–15 years. Risk behaviors for myopia which included sleep duration, homework time, and outdoor activity were measured by self-administrated questionnaire. Myopia was defined according to a validated method, and its relationships with menarche status and behaviors were evaluated by robust Poisson regression models based on generalized estimated equation adjusting for cluster effect of school. We found that postmenarche girls were at 13% (95% confidence interval: 11%–16%) higher risk of myopia than premenarche girls, after adjusting for exact age, urban–rural location, survey year, and four behavioral covariates. Short sleep duration (<7 h/d), long homework time (>1 h/d) and low frequency of weekend outdoor activity tended to be stronger (with higher prevalence ratios associated with myopia) risk factors for myopia in postmenarche girls than in premenarche girls, and their interaction with menarche status was all statistically significant (P < 0.05). Overall, our study suggests that menarche onset may be associated with increased risk of myopia among school-aged girls and could also enhance girls’ sensitivity to myopia-related risk behaviors.

A 70-year-old woman was seen in neuro-ophthalmology consultation for a progressive right esotropia. She had a past medical history of asthma and osteoporosis, and her ocular history was significant for pathological myopia (spherical equivalent of −23.00 D OD and −21.00 D OS), bilateral cataract surgeries, and laser retinopexy for retinal tears. Twenty-five years prior to presentation, she developed binocular horizontal diplopia and was found to have a limitation of abduction to 60% and 80% of normal in the right and left eyes, respectively, by a previous neuro-ophthalmologist. She developed a progressive maculopathy in the right eye secondary to myopia, resulting in the resolution of double vision. The resolution occurred because the double vision was binocular in nature and the loss of vision in her right eye functioned similar to monocular occlusion. However, she noticed that her right eye continued to turn in toward her nose.

The primary aim of the Guangzhou Twin Eye Study (GTES) is to explore the impact that genes and environmental influences have on common eye diseases. Since 2006, approximately 1300 pairs of twins, aged 7–15 years, were enrolled at baseline. Progressive phenotypes, such as cycloplegic refraction, axial length, height and weight, have been collected annually. Nonprogressive phenotypes such as parental refraction, corneal thickness, fundus photo, intraocular pressure and DNA were collected once at baseline. We are collaborating with fellow international twin researchers and psychologists to further explore links with general medical conditions. In this article, we review the history, major findings and future research directions for the GTES.

This case study examined the hypothesis that longer outdoor time results in normal vision and refractive status, using unique genetically informative kinships. The participants were the members of 29-year-old doubly exchanged monozygotic male twin pairs from Bogotá, Colombia, in South America. Comprehensive ophthalmological examinations, including uncorrected and corrected visual acuity, refraction and keratometry, and visual life history interviews were undertaken; all examinations were conducted by two ophthalmologists blind to the hypothesis, relatedness, and rearing status of the four participants. Normal uncorrected vision and refractive status were present in the two rural-raised, unrelated brothers, relative to their urban-raised counterparts. Uncorrected visual acuities were 20/160 and 20/200 for the city-raised twins and 20/20 and 20/30 for the country-raised twins. Premature birth, low birth weight, computer use, and reading time could not explain these differences. It was concluded that time spent outdoors appears to be a significant factor in the development of myopia, reinforcing extant findings via a novel experimental approach.

Recent studies have demonstrated the defocus sign-dependent, bidirectional gene expression regulation of bone morphogenetic proteins, BMP2, 4 and 7 in chick RPE. In this study, we examined the effects of imposed positive (+10 D) and negative (−10 D) lenses on the gene expression of these BMPs and BMP receptors (BMPR1A, BMPR1B, BMPR2) in chick retina and choroid after monocular lens treatment for 2 or 48 h, as indicators of the roles of retinal and choroidal BMPs and receptors in postnatal eye growth regulation. In retina, although all genes were expressed, neither +10 nor −10 D lenses, worn for either 2 or 48 h, significantly altered gene expression. In contrast, treatment-related differential gene expression was detected in the choroid for both BMPs and their receptors, although interestingly, with the +10 D lens, BMP2 was up-regulated by 156.7 ± 19.7% after 2 h, while BMPR1A was down-regulated to 82.3 ± 12.5% only after 48 h. With the −10 D lens, only the gene expression of BMPR1B was significantly altered, being up-regulated by 162.3 ± 21.2% after 48 h. Untreated birds showed no difference in expression between their two eyes, for any of the genes examined. The finding that retinal gene expression for BMP2, 4, 7 and their receptors are not affected by short-term optical defocus contrasts with previous observations of sign-dependent expression changes for the same genes in the RPE. The latter changes were also larger and more consistent in direction than the choroidal gene expression changes reported here. The interrelationship between these various changes and their biological significance for eye growth regulation are yet to be elucidated.

This study quantitatively investigated the immediate effects of a photooxidative collagen cross-linking treatment with photosensitizer riboflavin (RF) and 370 nm UVA light in in vitro human corneoscleral collagen fibrils using histology, thickness, scanning electron microscopy, and atomic force microscopy analyses. Twenty 8 × 2 mm corneoscleral strips were dissected sagittally from donor tissue using a scalpel. Four parameters were investigated, including the density, thickness, adhesion force, and stiffness of corneoscleral tissues before and after the collagen cross-linking treatment. The RFUVA-catalyzed collagen cross-linking treatment led to an increase in the density of both corneal (8%) and scleral (23%) stromal collagens. However, there was no difference in corneoscleral thickness. Furthermore, RFUVA-catalyzed collagen cross-linking treatment led to an increased biomechanical response of corneosclera: 25 and 8% increases in corneoscleral stiffness, and 24 and 22% increases in corneoscleral adhesion force. The collagen cross-linking treatment through RF-sensitized photoreaction may cause structural and biomechanical changes in the collagen fibril network of the cornea and the sclera. This is due to narrowing of the interfibrillar spacing and the stromal edema.

Visual impairment is a leading cause of morbidity and poor quality of life in our community. Unravelling the mechanisms underpinning important blinding diseases could allow preventative or curative steps to be implemented. Twin siblings provide a unique opportunity in biology to discover genes associated with numerous eye diseases and ocular biometry. Twins are particularly useful for quantitative trait analysis through genome-wide association and linkage studies. Although many studies involving twins rely on twin registries, we present our approach to the Twins Eye Study in Tasmania to provide insight into possible recruitment strategies, expected participation rates and potential examination strategies that can be considered by other researchers for similar studies. Five separate avenues for cohort recruitment were adopted: (1) piggy-backing existing studies where twins had been recruited, (2) utilizing the national twin registry, (3) word-of-mouth and local media publicity, (4) directly approaching schools, and finally (5) collaborating with other research groups studying twins.

Studies have reported that refractive errors are associated with premature births. As twins have higher prevalence of prematurity than singletons, it is important to assess similarity of the prevalence of refractive errors in twins and singletons for proper interpretations and generalizations of the findings from twin studies. We compared refractive errors and diopter hours between 561 pairs of twins and 3757 singletons who are representative of school-age children (7–15 years) residing in an urban area of southern China. We found that the means and variances of the continuous measurement of spherical equivalent refractive error and diopter hours were not significantly different between twins and singletons. Although the prevalence of myopia was comparable between twins and singletons, that of hyperopia and astigmatism was slightly but significantly higher in twins than in singletons. These results are inconsistent with those of adult studies that showed no differences in refractive errors between twins and singletons. Given that the sample size of twins is relatively small and that this study is the first to demonstrate minor differences in refractive errors between twins and singletons, future replications are necessary to determine whether the slightly higher prevalence of refractive errors in twins than in singletons found in this study was due to a sampling error or to the developmental delay often observed in twins in childhood.

The chicken has been extensively studied as an animal model for myopia because its eye growth is tightly controlled by visual experience. It has been found that the retina controls the axial eye growth rates depending on the amount and the sign of defocus imposed in the projected image. Glucagonergic amacrine cells were discovered that appear to encode for the sign of imposed defocus. It is not clear whether the downstream neurons, the retinal ganglion cells, still have access to this information—and whether it ultimately reaches the brain. We have analyzed the spike rates of chicken retinal ganglion cells in vitro using a microelectrode array. For this purpose, we initially defined spatial resolution and contrast sensitivity in vitro. Two classes of chicken retinal ganglions were found, depending on the linearity of their responses with increasing contrast. Responses generally declined with increasing defocus of the visual stimulus. These responses were well predicted by the modulation transfer function for a diffraction-limited defocused optical system, the first Bessel function. Thus, the studied retinal ganglion cells did not distinguish between a loss of contrast at a given spatial frequency due to reduced contrast of the stimulus pattern or because the pattern was presented out of focus. Furthermore, there was no indication that the retinal ganglion cells responded differently to defocus of either sign, at least for the cells that were recorded in this study.

Our previous studies suggested that reduced choroidal blood flow (CBF) occurs with manipulations that yield myopic eye growth and that these reductions are primarily a consequence of the ocular enlargement. We could not entirely rule out the possibility, however, that reductions in CBF are at least to some extent antecedent and causal to the ocular enlargement. We therefore in the present study examined the effects on eye size of artificially reducing CBF by unilaterally transecting the choroidal nerves of the ciliary ganglion in four-day-old chicks. For comparison, we also transected the ciliary nerves in a second group of chicks or transected both ciliary and choroidal nerves in a third group of chicks. The effects of the nerve transections were evaluated in comparison to the effects of the orbital surgery itself (without nerve transection) in a fourth group termed the sham-operated control group. Two weeks after transection, CBF was measured using laser Doppler velocimetry, the ocular axial, nasotemporal and dorsoventral lengths were measured, and the eyes weighed.

The results showed that CBF in birds with either choroidal nerve cuts or choroidal plus ciliary nerve cuts was greatly reduced in the treated eye (20–40% of nontreated eye). The treated eyes of these birds also showed gross depigmentation and histologically evident loss of the outer retina, most typically in the temporal retina. Birds with ciliary nerve cuts showed increased CBF in both eyes (131% right eye and 154% left eye compared to shams). Since ciliary nerve cuts yield fixed dilated pupils, increased CBF with ciliary nerve cuts appears consistent with the previously reported involvement of the choroidal nerves within a neural circuit subserving light-mediated upregulation of CBF. Clear effects on eye size were observed in the treated eyes in each group. The sham surgery alone yielded slight enlargement of the right eye compared to left eye, particularly in the axial dimension. In the choroidal nerve and the both nerve cut groups, nasotemporal and dorsoventral elongation were slightly diminished in the treated eyes compared to the sham-treated eyes. In contrast, enlargement of the right eye was slightly enhanced in the ciliary nerve cut group compared to the sham-treated eyes. The overall results suggest that large decreases in CBF do not enhance myopic eye growth, although large increases in CBF may.

The eyes of growing chicks adjust to correct for myopia (eye relatively long for the focal length of its optics) or hyperopia (eye relatively short for the focal length of its optics). Eyes made functionally hyperopic with negative spectacle lenses become myopic and long, whereas eyes made functionally myopic with positive spectacle lenses become hyperopic and short. We report here that these compensatory growth adjustments occur not only in normal eyes but also in eyes unable to accommodate (focus) because of lesions to the Edinger-Westphal nuclei. Thus, at least in chicks, accommodation is not necessary for growth that reduces refractive errors during development, and may not be necessary for the normal control of eye growth.

Studies of form-deprivation myopia (FDM) in animal models have shown that postnatal ocular growth is regulated by the quality of patterned images on the retina. One of the major challenges in myopia research is to identify the biochemical mechanisms which translate retinal visual responses into signals that regulate scleral growth. Dopamine (DA) has been implicated in this process, since retinal DA levels decline in FDM and subconjunctival injections of apomorphine (Apo, a nonspecific DA agonist) prevent FDM in a dose-dependent way (Stone et al., 1989).

To gain insight into where and how DA ligands act to regulate ocular elongation, we compared the action and distribution of DA receptor ligands injected intravitreally vs. subconjunctivally in young chicks. Ocular length was measured by A-scan ultrasound. We found that daily intravitreal injections of Apo block FDM at a 50% effective dose (ED50) of 5 pg per day, or a peak concentration in the vitreous humor of 108 pM, compared to an ED50 of 2.5 ng for subconjunctival injections as reported by Stone et al. (1989, 1990). [3H]-spiperone, a D2-receptor antagonist, reached average maximum retinal concentrations of 160 pM and 260 pM, during the first hour after intravitreal and subconjunctival administration, respectively, at the ED50 dose. In contrast, the maximum spiperone concentrations in the retinal pigment epithelium (RPE) were 30 pM and 410 pM, respectively, after intravitreal or subconjunctival ED50 doses. Spiperone concentrations in sclera after ED50 doses to the two sites differed by 4 x 104 (0.4 pM vs. 1.7 nM, respectively). The FDM-preventing action of Apo was blocked completely by simultaneous administration of spiperone but not by SCH 23390 (a D1-receptor antagonist) in 100-fold molar excess.

These results show that apomorphine acts to prevent FDM at an intraocular site, presumably in retina and/or pigment epithelium, but not sclera, whether administered intravitreally or subconjunctivally. A dose yielding a concentration of 100–260 pM, delivered ≤1 h per day, produces half-maximal inhibition. This action is mediated by D2-receptors, for which the dissociation constant for apomorphine is ≤1 nM. The retinal pigment epithelium may act as a trophic relay station, responding to a retinal messenger which may be DA and secreting scleral growth-regulator(s) from its basal surface.

Increasing evidence indicates that the retina takes part in the postnatal regulation of eye growth, functioning in this respect to minimize refractive error. The evidence derives both from clinical observations in man and from experiments in animals. The discovery that visual form deprivation leads to an axial overgrowth of the eye and to myopia has opened the way to many current research initiatives. Neurochemical and immunocytochemical experiments in chick and monkey suggest that definable retinal neurons participate in the regulatory pathway controlling eye growth. The most comprehensive data presently implicate dopaminergic amacrine cells. Other important issues to be addressed include the relevance of an intact connection to the central nervous system and the precise retinal mechanism by which eye growth is regulated.