Franchising structure changes and shareholder value: Evidence from store buybacks and refranchising.

Drawing on agency theory and transaction cost analysis, this study investigates the impact of refranchising and buybacks of downstream retail units by franchising firms on shareholder value (i.e., stock returns). It further evaluates the contingency role of firm and industry factors in shaping this impact. An event study analysis over the years 2001-2020 confirms that both refranchising and buybacks positively affect stock returns. However, notable impact differences emerge between the two types of strategic decisions. For refranchising, firms with lower royalty rates, smaller returns-on-assets (ROA), and higher trade credit provided generate higher stock returns. Whereas, for buybacks, firms with higher royalty rates derive more value in stock markets. Analysis further shows that investors judge refranchising (buybacks) less (more) favorably in munificent industries, but industry dynamism has no effect on the stock returns generated from these moves. Together, the study offers important implications for franchising theory and retail practice in marketing. Supplementary Information: The online version contains supplementary material available at 10.1007/s11747-022-00921-3.

A Comparative Review of the Extrinsic and Intrinsic Factors Regulating Lactose Synthesis.

Milk is critical for the survival of all mammalian offspring, where its production by a mammary gland is also positively associated with its lactose concentration. A clearer understanding of the factors that regulate lactose synthesis stands to direct strategies for improving neonatal health while also highlighting opportunities to manipulate and improve milk production and composition. In this review we draw a cross-species comparison of the extra- and intramammary factors that regulate lactose synthesis, with a special focus on humans, dairy animals, and rodents. We outline the various factors known to influence lactose synthesis including diet, hormones, and substrate supply, as well as the intracellular molecular and genetic mechanisms. We also discuss the strengths and limitations of various in vivo and in vitro systems for the study of lactose synthesis, which remains an important research gap.

A Comparative Review of the Cell Biology, Biochemistry, and Genetics of Lactose Synthesis.

Lactose is the primary carbohydrate in the milk of most mammals and is unique in that it is only synthesized by epithelial cells in the mammary glands. Lactose is also essential for the development and nutrition of infants. Across species, the concentration of lactose in milk holds a strong positive correlation with overall milk volume. Additionally, there is a range of examples where the onset of lactose synthesis as well as the content of lactose in milk varies between species and throughout a lactation. Despite this diversity, the precursors, genes, proteins and ions that regulate lactose synthesis have not received the depth of study they likely deserve relative to the significance of this simple and abundant molecule. Through this review, our objective is to highlight the requirements for lactose synthesis at the biochemical, cellular and temporal levels through a comparative approach. This overview also serves as the prelude to a companion review describing the dietary, hormonal, molecular, and genetic factors that regulate lactose synthesis.

Differences in Diagnosis and Treatment of Nipple Conditions of Reproductive-Age Women at a Tertiary Health System.

Background: Nipple-areolar complex (NAC) conditions affect reproductive-age women, yet it is not known how care of NAC complaints is distributed among medical specialties. There is a need to characterize all NAC conditions, including their treatment and the care team involved in their clinical management, of nonlactating and lactating patients to determine care gaps. Materials and Methods: This was a retrospective cohort study of reproductive-age females who presented to a large tertiary health system with an NAC complaint between 2015 and 2020. Data about the symptoms, diagnosis, specialty providing care, diagnostic considerations, and treatments were collected. Results: Nipple pain, dermatitis, and thrush were the most common diagnoses among 407 encounters (215 patients). Lactating patients represented half (204, 50%) of the study sample. Benign breast conditions like obstructed ductal openings, accessory nipples, nipple growth, inverted nipples, and chronic and bacterial infections represented a third of all encounters. Primary care physicians (167, 41%) and obstetricians (105, 26%) provided most of the care and referred a third and quarter of patients, respectively, to another provider. Conclusion: The care of patients with NAC complaints is not limited to obstetricians. Internal medicine, family medicine, emergency medicine, and obstetrician-gynecology, dermatology, and surgery resident physicians should receive training in benign breast conditions and clinical lactation.

A Delphi-Style Evaluation of a Skin Assessment Simulation Using Clinical Vignettes and a Breast Health Training Tool.

INTRODUCTION: Breast and skin assessment are both required clinical skills across health professional training programs. The breast is an ideal "canvas" for the development of a simulation exercise focused on the identification and diagnosis of skin conditions that could present anywhere on the body alongside unique conditions specific to the breast and nipple-areolar complex. A skin assessment simulation on a breast model has not been described. METHODS: Investigators developed 20 clinical vignettes for breast and skin conditions (ie, features) depicted on a set of 10 single silicone breast models in 4 skin tones. A modified Delphi approach was used to evaluate the appropriateness of the clinical vignettes and realism of features. A convenience sample of 136 licensed physicians was recruited online. In round 1, participants rated the realism of features and suggested descriptors for each feature. In round 2, participants rated their agreement with descriptors from round 1, selected a diagnosis based on clinical vignettes, and assessed the utility of the Breast Health Training Tool for health professionals. RESULTS: In round 1, participants (n = 38) agreed (5.1/6) that the features were realistic. In round 2, participants (n = 24) agreed (4.6/6) with the descriptors. Most (>50%) participants agreed on a diagnosis for each feature. Participants (n = 27) agreed (5.3/6) that this tool is useful for health professional education. CONCLUSIONS: This is the first evaluation of a simulation tool for teaching breast examination and identification of skin conditions on the nipple-areolar complex and breast tissue in multiple skin tones, simultaneously filling the gap in women's breast, lactation, and skin health education.

Comparison of Breastfeeding Practices in Mothers With Chronic Kidney Disease With or Without Kidney Transplantation.

Introduction: Existing literature on pregnant patients with chronic kidney disease (CKD) with or without kidney transplantation focuses mainly on their pregnancy outcomes, but there are scant data on their lactation outcomes. Our objective was to characterize the lactation outcomes of patients with CKD with or without kidney transplantation. Methods: This is a single-institution retrospective cohort study of female-identifying patients with CKD with or without kidney transplantation who had a birth hospitalization at a tertiary health system between 2010 and 2020. Maternal and pediatric data on medical history, pregnancy, delivery, neonatal, and lactation outcomes, medications, and care team involved were collected. Primary outcome measures were breastfeeding initiation within 24-hour postpartum, breastfeeding 8 or more times per day during hospitalization, and any breastfeeding beyond 1 month. Health professionals' comments related to lactation and medications were extracted for qualitative data analysis. Results: Patients with and without kidney transplantation had similar comorbidities, pregnancy, delivery, and neonatal outcomes, and hospital length of stay (p > 0.05). Patients without kidney transplantation were more likely to initiate breastfeeding in the first 24 hours (p = 0.03) after delivery and continue breastfeeding beyond 1 month postpartum. There was a lack of consistency between specialties regarding medication compatibility with lactation. Patients on immunosuppression were more likely to exclusively formula feed (p = 0.02) or to initiate breastfeeding and then switch to formula (p = 0.0004) because of their immunosuppressive medications versus patients on any other medication. Conclusion: Patients with CKD but without a kidney transplantation were more likely to initiate breastfeeding or provide breast milk to their infant within 24 hours of delivery, breastfeed >8 times per day during their hospital stay, and breastfeed beyond a month postpartum than those with a transplanted kidney. Lactation support and pharmacology should be incorporated into graduate medical education.

An Application of Kane's Validity Framework to Evaluate Formative and Summative Assessment Instruments for Telesimulations in Clinical Lactation.

INTRODUCTION: Health professional learners have limited exposure to breastfeeding patients from diverse backgrounds in clinical rotations. Instead, simulation-based training is used for lactation skills training. There are no validated or standardized simulations and assessment rubrics for lactation. In this pilot, breastfeeding telesimulations with standardized patients (SPs) wearing a high-fidelity breast model matching their skin tone were developed. The validity of Formative and Summative Assessment Rubrics (FAR, SAR) were assessed following Kane's validity framework. The objective was to provide initial evidence for the validity of the FAR and SAR as constructs of competence in lactation support at the entry to practice or practice level. METHODS: Three breastfeeding case scenarios, FAR, and SAR were developed and evaluated with clinical lactation specialists (evaluators, n = 17) and SPs. The FAR was used in practice telesimulations where SPs' (n = 14) performance and telesimulation feasibility were assessed. The FAR was updated in preparation for a pilot study where medical students (n = 13) completed the 3 telesimulations. In the pilot, the updated FAR was used by SPs (n = 6) to assess medical students' performance of clinical skills. After the pilot, rubrics were updated after focus groups with SPs and discussions with evaluators. Evaluators (n = 3) graded students' posttelesimulation documentations using the SAR. Cronbach ɑ level and the intraclass correlation coefficient were assessed iteratively to collect evidence for the scoring, generalizability, and extrapolation of the FAR and SAR according to Kane's framework. RESULTS: The FAR and SAR were found to have acceptable internal consistency and moderate to high interrater reliability (intraclass correlation coefficient, 0.55-0.94), which provided evidence for scoring and generalizability of the instruments. Evaluators agreed that SPs' performances were realistic (5.6/6), and SPs' feedback was organized (5.5/6) and helpful (5.6/6), which provided evidence for extrapolation. CONCLUSIONS: Initial evidence for validity of scoring, generalization, and extrapolation FAR and SAR (according to Kane's framework) in assessing health professional learner's performance of clinical lactation skills has been presented. These results from a pilot study suggest that the FAR and SAR are reliable instruments for assessing learners' clinical performance in a breastfeeding-focused telesimulation where the SP wears a high-fidelity breast model matching their skin tone. Additional studies will be required to collect evidence according to all 4 categories of Kane's framework for the validity of the FAR and SAR.

Development of Team Behavior Skills and Clinical Lactation Competence Among Medical Students Engaging in Telesimulations with Standardized Patients.

Objective: The aims of this pilot feasibility study were to determine if telesimulations with standardized patients (SPs) wearing high-fidelity breast models impact students' team behavior and clinical competence in lactation support. Materials and Methods: Medical students (N = 19) completed five telesimulations: Cases 1, 2, 5 in a team, 3 as individual, and 4 randomized. SPs used the Formative Assessment Rubric (FAR) to evaluate interpersonal and clinical competence. Collaboration skills within team-based telesimulations (Cases 2 and 4) were rated using the Interprofessional Collaborator Assessment Rubric (ICAR). Satisfaction data were collected from a focus group and written evaluation. Descriptive statistics were calculated for FAR, ICAR, and written evaluations. Appropriate nonparametric tests were used to measure FAR and ICAR differences over time or between team and individual telesimulations and the relationship between FAR and ICAR scores. Content analysis was used to generate themes from focus group data. Results: Learners' interpersonal and lactation-specific competence improved over time (p = 0.003 and 0.009, respectively). Learners were able "to accept responsibility for their actions" more but spent less time "seeking perspectives from peers" in Case 4 compared with Case 2 (p = 0.01 and p < 0.001, respectively). Themes from the focus group related to the value of team telesimulations to learn clinical lactation skills and learn about one's role in a team. Learners agreed they developed clinical lactation skills (>4.5/5-pt). Conclusions: Opportunities to work collaboratively in telesimulations with a SP prepare learners for professional collaborations to effectively care for breast/chestfeeding dyads.

Transcriptomic changes underlying glucocorticoid-induced suppression of milk production by dairy cows.

Milk production by dairy cows is sensitive to increased levels of stress hormones such as glucocorticoids (GC) that also regulate the transcription of several genes required for milk synthesis. Whereas previous studies identified that an exogenous GC such as dexamethasone (DEX) transiently suppresses milk yield in several species without any pronounced effect on milk protein or fat percentage, the mechanism underlying this effect has not been established. In this study we sought to establish changes within the mammary glands of non-pregnant dairy cows in their second lactation (n = 3-4; 648-838 kg) following a single dose of exogenous DEX. Changes in the udder were monitored by serial biopsy of alternating quarters, concurrent with quarter-level monitoring of milk yield and composition. Dexamethasone increased serum glucose levels from 12-36 h (p <0 .05), reduced milk yield from 12-48 h (p <0 .05), increased % milk protein content at 24 h post-DEX, and transiently decreased both milk lactose and α-lactalbumin content, while not altering the level of milk fat. After 72 h, all aspects of milk production had returned to pre-treatment levels. Transcriptomic changes in the mammary glands in response to DEX were identified by RNA sequencing followed by differential gene expression analysis. Coincident with the milk yield and composition changes was the differential expression of 519 and 320 genes at 12 and 24 h after DEX (adjusted p <0 .05), respectively, with the return of all gene expression to baseline levels by 72 h. Among the transcriptomic changes in response to DEX, there was notable downregulation of elements in the lactose synthesis pathway, specifically AQP3, GALE and LALBA (α-lactalbumin) at 12 h, and sustained downregulation of LALBA at 24 h. One gene in the pathway, UGP2, was upregulated at 12-24 h post-DEX. This work supports the hypothesis that there is a direct relationship between the response to DEX and the concurrent suppression of milk yield due to the reduced synthesis of α-lactalbumin and lactose by the mammary epithelium. The ability of glucocorticoids to modulate the homeorrhetic requirements for glucose during stressful states concurrent with immune activation bears significance for dairy animals as well as a broad range of lactating mammals.

A pilot study to evaluate the effect of classroom-based high-fidelity simulation on midwifery students' self-efficacy in clinical lactation and perceived translation of skills to the care of the breastfeeding mother-infant dyad.

BACKGROUND: Midwives are expected to provide timely and skilled support to breastfeeding mothers, yet it is not clear whether and how midwifery students receive training in clinical lactation. The primary objective of this pilot study was to evaluate the impact of a classroom-based breastfeeding simulation on nurse-midwifery students' self-efficacy in lactation skills. The secondary objective was to describe students' exposure to breastfeeding patients in the classroom and in clinical settings. METHODS: A pilot study using a prospective cohort study design and convenience sampling was completed between September 2017 and April 2018. Two simulation-based workshops were developed for the classroom setting in alignment with breastfeeding-focused competencies for midwives and lactation professionals. The workshops were integrated into the nurse-midwifery curriculum at a US-based program. Two Self-Efficacy Surveys (defined, 7-point Likert Scale) were developed and used to measure baseline and continuing self-efficacy in breastfeeding skills among students. Two Practice Patterns instruments, adapted from the American Academy of Pediatrics breastfeeding curriculum, were used to define the setting, quantity, and types of nurse-midwifery students' breastfeeding-related exposures. Students participated in a one-hour focus group upon completion of the study. RESULTS: In this pilot study, nurse-midwifery student participants (N = 9) reported a 14% increase (P < .0001) in their perceived self-efficacy in basic and advanced clinical lactation skills after completing both workshops. The nurse-midwifery students reported dozens of encounters with diverse breastfeeding patients over a six-month period during which they performed a wide variety of clinical lactation skills. The focus group revealed most students (n = 5/9) would like more time to practice clinical lactation skills in a simulated environment and some indicated a desire to have more exposure to challenging versus common (n = 2/9) of breastfeeding concerns. CONCLUSIONS: In this work, we demonstrate the first high-fidelity lactation simulation in a classroom setting in a healthcare professional training program. Midwifery educators and researchers can adapt the framework and instruments presented in this pilot study to determine the effect of educational interventions on students' translation of skills to breastfeeding mother-infant dyads. Likewise, this is the first study to define the number and type of breastfeeding-related clinical exposures among nurse-midwifery students.

The Efficacy of Hybrid Telesimulation with Standardized Patients in Teaching Medical Students Clinical Lactation Skills: A Pilot Study.

Introduction: Medical students lack competencies in clinical lactation. We determined the effect of hybrid telesimulation with a standardized patient (SP) on medical students' clinical performance in lactation support. We assessed students' engagement and satisfaction with the experience. Materials and Methods: Undergraduate medical students (n = 13) completed (1) preparatory case scenarios with multiple-choice questions and (2) three telesimulations with SPs wearing a high-fidelity breast model. Students had the option to complete the Encounter Documentation. SPs used the Formative Assessment Rubric (FAR) to evaluate students' interpersonal skills and clinical lactation experts used the Summative Assessment Rubric to evaluate documentation skills. Investigators collected satisfaction data from a focus group and written evaluation. Dunn's multiple comparison and Freidman tests were used to measure differences in FAR scores between cases and telesimulations. Qualitative data were analyzed using thematic analysis. Results: Most students (70%) attempted case questions multiple times and scores improved (p < 0.0001) between attempts. FAR scores suggest students were prepared for telesimulations (5.5/6-pt Likert) and interpersonal skills were appropriate (5.4/6), with no differences by case (p = 0.11). FAR scores increased between telesimulation 1-2 (+24.5/114, p = 0.002) and 2-3 (+17.5/114, p = 0.014). Students were satisfied with the experience and would recommend it to classmates (both 4.6/6). Thematic analysis revealed feedback regarding interpersonal skills was helpful. Conclusions: Medical students must develop skills to support breastfeeding in virtual settings. Telesimulation can be incorporated into existing curricula to support clinical lactation competencies.

Midwifery students better approximate their self-efficacy in clinical lactation after reflecting in and on their performance in the LactSim OSCE.

BACKGROUND: Midwives are expected to support women with lactation initiation and maintenance. Midwifery students engaged in a simulation-based exercise (LactSim OSCE) where they role-played the clinician and the breastfeeding patient by wearing a high-fidelity breast model. We provided participants opportunities for reflecting in and on practice to compare their perceived self-confidence in clinical lactation skills to actual clinical performance. We also describe feasibility of implementing the LactSim OSCE with an emphasis on preparation and time spent on tasks during the OSCE. METHODS: Audio-video recordings from the LactSim OSCE were viewed and assessed using a technical skills checklist by an independent rater and by the study participants as part of the self-reflection. Mixed data on participants' self-efficacy in clinical lactation, experience with the LactSim OSCE, and self-assessment of clinical performance were collected in survey instruments and a focus group. Time spent on each component and clinical lactation skill during the LactSim OSCE was documented. RESULTS: Immediately following the LactSim OSCE, participants' confidence in clinical lactation was high (5.7/7), but after a guided video reflection exercise, their self-efficacy was 4.4/7. Participants spent approximately 2 of the allotted 10 min per case scenario discussing the OSCE logistics due to inadequate preparation. Participants spent approximately 2 min of the total encounter performing hands-on clinical lactation skills by touching, looking at, or using the high-fidelity breast model worn by their peer. CONCLUSION: We described the development and evaluation of the first simulated experience in clinical lactation with all three components of fidelity: conceptual, psychological, and physical. Multiple opportunities for reflecting on performance allowed the nurse-midwifery students to evaluate their competence in decision-making, technical, and counseling skills which resulted in a more realistic approximation of their perceived self-confidence in breastfeeding skills. Another innovation of this pilot work is the documentation of how long a learner spends on various tasks relevant to lactation support in a simulated encounter. Our findings highlight the importance of providing multiple opportunities for self-reflection using guided video reflection and checklists for objective self-assessment in the clinical lactation field.

Development and evaluation of a high-fidelity lactation simulation model for health professional breastfeeding education.

BACKGROUND: A key reason for premature cessation of breastfeeding is inadequate support from healthcare providers. Most physicians and nurses do not feel confident in their ability to support families with breastfeeding initiation or maintenance. Increasing health professional confidence in clinical lactation skills is key to improving maternal and child health outcomes. High-fidelity (realistic) simulators encourage learner engagement, resulting in increased clinical skills competency, confidence, and transfer to patient care. Lactation educators teach with low-fidelity cloth and single breast models. There are no high-fidelity breast simulators for health professional education in clinical lactation. DEVELOPMENT AND EVALUATION OF A HIGH-FIDELITY LACTATION SIMULATION MODEL: In this commentary we describe the development of a high-fidelity Lactation Simulation Model (LSM) and how physician residents, nurse-midwifery students, and clinical lactation experts provided feedback on LSM prototypes. LIMITATIONS: The user-testing described in this commentary does not represent comprehensive validation of the LSM due to small sample sizes and the significant conflict of interest. CONCLUSION: For breastfeeding rates to improve, mothers need support from their nurses, midwives, pediatricians, obstetricians and gynecologists, and all healthcare staff who interact with pregnant and lactating women. Clinical education with high-fidelity breastfeeding simulators could be the ideal learning modality for trainees and hospital staff to build confidence in clinical lactation skills. The ability of a high-fidelity breastfeeding simulator to increase a learner's lactation knowledge and psychomotor skills acquisition, retention, and transfer to patient care still needs to be tested.

Features and Educational Content Related to Milk Production in Breastfeeding Apps: Content Analysis Informed by Social Cognitive Theory.

BACKGROUND: Low milk production is one of the main reasons for premature breastfeeding cessation. Smartphone apps have the potential to assist mothers with promoting, interpreting, tracking, or learning about milk production. It is not known whether breastfeeding apps contain high-quality, engaging, and diverse content and features that could be used by mothers to increase their breastfeeding self-efficacy and answer their questions about milk production. OBJECTIVE: The overarching objective of this study was to identify and evaluate features and content within breastfeeding apps that could be used by mothers to increase breastfeeding self-efficacy and answer their questions about milk production. The secondary objectives were to quantify the diversity of representation of breastfeeding experiences within breastfeeding apps and to define the type of organization that is most likely to create free apps and/or apps with high-quality, engaging, and diverse features and content related to milk production. METHODS: Breastfeeding apps were identified in the Apple App Store. All features that assist mothers with tracking, promoting, or interpreting milk production in the first 0-6 months postpartum were noted. Every screen containing educational information about milk production was identified and saved for review. Images of mothers and caretakers within the selected screenshots were assessed. Three scoresheets informed by Social Cognitive Theory were created to evaluate all identified features, educational content, and images representing the breastfeeding experience. RESULTS: Forty-one breastfeeding apps were reviewed. Only seven apps contained both features and educational content related to milk production. Thirteen apps that contained educational content related to milk production received a mean combined content and cultural diversity score of 15.3 of 78. Of the 48 photos reviewed in screenshots that contained educational content on milk production, 87.5% (n=42) were of white women and their infants. For-profit companies and large organizations were most likely to create free apps and apps that received high scores on the combined content and diversity or features scoresheet, respectively. CONCLUSIONS: Features and educational content related to milk production and breastfeeding imagery within breastfeeding apps were evaluated using three novel scoresheets informed by Social Cognitive Theory. Few apps contained both features that promote breastfeeding self-efficacy and high-quality, engaging, educational content with images of diverse caretakers. Thus, it is likely that parents, especially those from minority or low-income groups, have limited options when selecting a breastfeeding app. App developers could use the scoresheets and findings in this review to develop breastfeeding apps that assist mothers with interpreting, tracking, or learning about milk production through high-quality and engaging features, content, and imagery.

Conjunctival lymphatic response to corneal inflammation in mice.

Due to its unique characteristics, the cornea has been widely used for vascular research. However, it has never been studied whether lymphatic vessels in the conjunctiva, its neighboring tissue, are affected by corneal lymphangiogenesis (LG). The purpose of this study was to investigate whether the distribution pattern of conjunctival lymphatic vessels changes during LG using a standardized two-suture placement model. Our data from immunofluorescent microscopic studies demonstrate, for the first time, that conjunctival lymphatic vessels were more distributed in the nasal side under both normal and inflamed conditions. Additionally, under the inflamed condition, conjunctival lymphatic vessels showed a higher density and more branching points, indicating that LG occurs in the conjunctiva in response to corneal inflammation. This study not only provides novel insights into lymphatic events in the ocular surface but also offers new guidelines for developing therapeutic strategies to treat lymphatic diseases at related sites.

Increased lymphangiogenesis and hemangiogenesis in infant cornea.

BACKGROUND: Corneal lymphangiogenesis (LG) and hemangiogenesis (HG) accompany many diseases after inflammatory, infectious, traumatic or chemical insults. They also contribute to transplant rejection. It is known that corneal transplants in infants or children have a higher rejection rate than in adults. However, it has never been studied whether infant corneas differ from adult corneas in inflammatory LG, HG, or both, which is the focus of this study. METHODS AND RESULTS: Corneal inflammatory LG and HG were induced by a standard suture placement model in C57BL/6 mice of 3 weeks and 8 weeks of age, respectively. Corneal LG, HG, and macrophage infiltration were assessed by immunofluorescent microscopic studies using specific antibodies against CD31 (a panendothelial cell marker), LYVE-1 (a lymphatic marker), and F4/80 (a macrophage marker). Blood vessels were also examined by ophthalmic slit-lamp microscopic assays in vivo. Digital images were analyzed by NIH Image J software. It was found, for the first time, that infant corneas exhibited a higher level of LG, HG, and macrophage infiltration during inflammation. Infant lymphatic and blood vessels demonstrated greater density and invasion area but similar branching points. Additionally, infant lymphatic vessels were also of larger diameter. CONCLUSIONS: Infant and adult corneas differ greatly in their inflammatory responses of LG, HG, and macrophage infiltration. These novel findings will shed some light on our understanding of the LG and HG processes, as well as the development of new therapeutic protocols for corneal diseases, particularly, in infants or children, where an early restoration of sight is critically important in preventing amblyopia or permanent vision loss.