Invention and Early Adoption

The automotive sun visor emerged in the early 1920s as a practical solution to the challenges of driving amid intense sunlight glare, particularly on the unpaved roads common at the time. In 1924, inventor Hathaway developed the first such device, known as a "glare shield," which was mounted externally on the Ford Model T to shield drivers' eyes from direct sunlight.[20] This innovation was influenced briefly by shading concepts from headwear visors, adapting them for vehicular use. The design addressed growing concerns over eye strain, exacerbated by post-1910s advancements like the widespread adoption of glass windshields and increasing vehicle speeds on dusty, unshaded roadways.[7]

Early adoption accelerated with the transition to internal visors for better accessibility and integration. By 1931, Ford began incorporating fabric-covered internal sun visors on select Model A vehicles, such as the Victoria, marking a shift from external mounts to more convenient interior placements using simple metal frames upholstered in fabric.[21] In the late 1920s, luxury manufacturer Packard introduced the first pull-down interior visor on its high-end models, allowing drivers to adjust shading more easily without leaving the cabin. These initial materials—primarily stamped metal for structure and basic fabric or leather coverings—prioritized durability and cost-effectiveness over aesthetics.[21]

By the 1930s, sun visors had become a standard feature on most U.S.-made automobiles, reflecting their proven role in enhancing driver safety and comfort amid expanding highway networks and higher travel speeds. Patents from the era, such as those detailing adjustable hinge mechanisms, further refined the basic design for smoother deployment and positioning. This rapid integration underscored the visor's evolution from a novel accessory to an essential component in automotive engineering.[7]

Design Advancements

Following World War II, automotive sun visor designs began incorporating lighter materials to improve usability and reduce headroom intrusion. In the 1950s, manufacturers like Ford introduced foam cores, such as latex or early urethane variants, as optional features to replace heavier fiberboard constructions, enabling slimmer profiles while maintaining structural integrity.[22] By the 1960s, functionality expanded with the addition of vanity mirrors on models including the Ford Mustang, providing passengers with personal grooming aids integrated into the visor body; illuminated versions, using simple electric bulbs, appeared as premium options to enhance visibility in low light.[23]

Material advancements in the 1970s focused on safety and durability, shifting from traditional fabric and vinyl coverings over rigid cores to energy-absorbing foams and emerging plastics like polycarbonate for select components, which offered shatter resistance during impacts. These changes aligned with the introduction of Federal Motor Vehicle Safety Standard (FMVSS) No. 201 in 1972, effective for new vehicles from 1973, which mandated that sun visors for front outboard seating positions be constructed of or covered with energy-absorbing material to limit head injury criteria (HIC) in crashes.[24] Dual-zone configurations, allowing independent adjustment and positioning for driver and passenger visors, became more prevalent to customize glare blocking without compromising the other's view.[25]

The 1990s brought further refinements for compatibility with advancing safety systems, particularly airbag deployment. Visor designs were engineered to minimize interference, using flexible hinges and tear-away fabrics to prevent the visor from becoming a projectile or obstructing inflation paths during frontal impacts, as emphasized in NHTSA guidelines for occupant protection.[26]

In the 2020s, innovations like Bosch's Virtual Visor represent a shift toward smart technology, employing a driver-facing camera with AI to detect eye position and a transparent LCD panel that selectively darkens only the glare-affected area, blocking sun rays without obscuring the forward view.[27] This builds on foundational glare shields from the 1920s while prioritizing unobtrusive functionality.

Team Sports Applications

Visors have played a significant role in team sports since the late 19th century, primarily aiding players in maintaining visibility under bright conditions while integrating team branding into uniforms. In baseball, extended brims on caps were introduced in the 1860s, when the Brooklyn Excelsiors adopted a rounded-top cap with a long peak designed specifically for sun shading during outdoor games.[28] This early design addressed the challenges of daytime play, allowing fielders and batters to track the ball without excessive glare.

By the 1920s–1930s, baseball caps were typically constructed from wool for added durability and structure, fitting seamlessly into team uniforms as a standard accessory. These models evolved in the 1980s with the incorporation of mesh panels in the crown and back, enhancing breathability and comfort during extended innings in hot weather. Modern Major League Baseball (MLB) caps feature adjustable designs with embroidered team logos.[29]

Design features of sports visors emphasize functionality, such as curved brims that provide shade without obstructing peripheral vision, enabling players to monitor teammates and opponents effectively.[30] Regulations govern visor use to ensure fairness; for instance, the National Collegiate Athletic Association (NCAA) mandates that eye shields remain clear or nearly clear—as of 2025, allowing "nearly clear" options—limiting tint levels to over 90% visible light transmission and preventing any unfair visibility advantages.[31][32]

In American football, eyeshields—transparent visors attached to helmets—emerged in the 1980s to protect against impacts and reduce glare, marking a shift toward integrated head protection. The National Football League (NFL) initially permitted tinted versions in the 1980s and 1990s but banned dark tints in 1998 for safety and visibility concerns among officials; lightly tinted options were reapproved in 2019 through a partnership with Oakley. Ice hockey goalies adopted clear visors on masks starting in the 1950s, with minor-league players using plastic shields for facial protection while preserving sightlines; this culminated in Jacques Plante's landmark 1959 NHL debut of a full protective mask, influencing team-wide standards. These applications reflect broader advancements in headwear, adapting protective elements from industrial designs to athletic needs.[33][34]

Individual Sports Uses

In individual sports such as golf and tennis, visors have long provided essential shading and comfort without restricting movement. Visors for active pursuits including golf emerged in the early 20th century, allowing players to shield their eyes from the sun while maintaining visibility on the course.[8] Early designs incorporated sweatbands to absorb perspiration during prolonged outdoor play.[35] In tennis, visors emerged as a fashion accessory in the 1920s, offering a lightweight alternative to full hats for players on sun-exposed courts.[36]

For cycling and running, clip-on visors gained popularity from the 1970s onward, prized for their aerodynamic profile and ability to provide targeted shading without adding bulk.[35] These models, often secured with elastic bands, help prevent sweat from dripping into the eyes during intense efforts like marathons, enhancing focus and endurance for solo athletes. In both disciplines, visors prioritize mobility, with crownless constructions promoting airflow to keep the head cool under exertion.

Key design features emphasize functionality for individual use: crownless styles facilitate ventilation, while UV-protective coatings block 100% of UVA and UVB rays to safeguard skin and eyes during extended exposure.[37] Brands like Nike introduced ventilated visors in the 1990s, featuring perforations for breathability that became staples in golf and tennis gear.

The evolution of sports visors reflects advancing materials and technologies tailored to solo activities. From simple fabric constructions in the 1920s, designs progressed with improved shading innovations, building on developments from team sports, underscoring visors' role in enhancing performance through lightweight, adaptive protection.[38]

Industrial and Welding Contexts

In industrial settings, visors serve as critical components of personal protective equipment (PPE) to shield workers from hazards such as flying debris, sparks, and intense light sources. Early designs in the 1910s consisted of hand-held shields, often made from basic materials like leather or metal frames with glass lenses, providing rudimentary protection during arc welding tasks.[39][40] These shields evolved into full helmets by the 1930s, with the introduction of green-tinted glass filters specifically for arc welding to attenuate harmful ultraviolet and infrared radiation while allowing visibility of the weld pool.[41]

Welding helmets incorporating flip-up visors became standard post-1930s, transitioning from fixed opaque shields to adjustable designs that balanced protection with usability. Materials advanced from leather and metal in the early 1900s, which offered durability but limited comfort, to impact-resistant plastics like fiberglass composites by the 1950s, enhancing lightweight protection against impacts and heat.[39][42] A significant innovation occurred in the 1980s with the commercialization of auto-darkening filters (ADF) using liquid crystal technology, pioneered by Swedish manufacturer Hornell (Speedglas), which automatically adjusts lens darkness from shade 9-10 in light state to shades 10-13 during welding arcs for optimal eye safety.[39][43] These ADF visors, typically rated for shades 10-13 in shielded metal arc welding, reduce the risk of arc eye by instantly blocking intense light while improving workflow efficiency over manual flip mechanisms.[44][45]

Beyond welding, face shields are essential in construction and machining, where they protect against flying particles and chemical splashes. The Occupational Safety and Health Administration (OSHA) established standards for eye and face protection in the 1970s under 29 CFR 1926.102 for construction, mandating shields that provide side protection and comply with impact resistance requirements to safeguard against hazards like debris from tools or machinery.[46] Modern industrial visors, primarily constructed from polycarbonate since the late 1970s, offer high impact resistance—capable of withstanding drops from 50 inches or high-velocity particles—while remaining lightweight and transparent.[47][48]

The ANSI/ISEA Z87.1 standard, first published in 1968 and updated periodically, governs impact resistance for face shields, requiring them to pass drop-ball and high-velocity tests to ensure no penetration or shattering under industrial stresses.[49] In machining applications, such as grinding or milling, visors often feature anti-fog coatings to maintain clear visibility in humid or high-heat environments, preventing condensation that could obscure hazards.[50][51] These coatings, applied to polycarbonate surfaces, enhance usability without compromising the material's inherent resistance to scratches and impacts.[52]

Medical and Emergency Applications

In medical settings, protective visors, often referred to as face shields, serve as essential personal protective equipment (PPE) for healthcare workers, including physicians, nurses, and dentists, to shield the face, eyes, and mucous membranes from splashes, sprays, and droplets of bodily fluids during procedures such as surgeries, examinations, and patient care.[53] These devices provide a transparent barrier that covers a larger facial area than goggles or surgical masks alone, reducing the risk of exposure to infectious pathogens like influenza or other respiratory viruses.[53] Studies have demonstrated their efficacy, with one experiment showing face shields reducing inhalational exposure to influenza aerosols by 96% at 18 inches and 92% at 72 inches from the source.[54] When combined with N95 respirators, they further prevent contamination of the eyes, nose, and mouth, enhancing overall infection control without requiring fit testing or causing significant fogging.[55]

In emergency medical services (EMS), visors are critical for first responders and paramedics during high-risk interventions, such as cardiopulmonary resuscitation (CPR), trauma assessments, or handling infectious cases in ambulances and accident scenes, where exposure to blood, vomit, or aerosols is common.[53] Their lightweight, adjustable designs allow for quick donning and doffing in fast-paced environments, and they can be easily disinfected between uses, extending the usability of other PPE like masks.[53] During the COVID-19 pandemic, visors were widely adopted in emergency departments as an adjunct or alternative to masks, though evidence indicates they are less effective against airborne transmission alone and should be paired with respirators for optimal protection.[56]

Beyond standard protective uses, specialized visor-like devices have emerged for diagnostic purposes in emergency care. The Cerebrotech Visor, a portable, non-invasive tool cleared by the FDA in 2018, uses low-power radio waves to detect hemispheric bioimpedance asymmetry indicative of ischemic strokes, enabling rapid assessment in under two minutes at the bedside or in ambulances.[57] Clinical trials, such as the VITAL II study, validated its accuracy in identifying large-vessel occlusions, with applications extending to monitoring cerebral edema and traumatic brain injuries in emergency settings.[58] This device supports timely interventions like thrombolysis, potentially improving outcomes in time-sensitive neurological emergencies.[59]

Origins in Armor

In medieval armor, a visor refers to a movable or fixed face guard integrated into helmets, designed to protect the wearer's face while allowing limited visibility through slits or perforations.[11] The term "visor" derives from the Old French visiere, meaning "face" or "appearance," from Latin visus ("a look, a seeing"), and was first attested in Middle English around 1300 as a reference to the front part of a helmet.[3] These early visors emerged in the 13th century as part of evolving helmet designs, initially appearing on the great helm—a large, cylindrical or barrel-shaped helmet worn over a mail coif—and later on the bascinet, a lighter skullcap-like helmet that became widespread in the 14th century.[12][11]

By the 14th century, visors on bascinets typically featured hinged mechanisms that could be raised or lowered, incorporating narrow vision slits to balance facial protection against blows with the need for battlefield awareness.[13] A notable example is the late 14th-century Lyle bascinet, a steel helmet with a detachable "houndskull" visor—characterized by its pointed, dog-like snout for deflecting strikes—and brass borders, demonstrating the period's advancements in articulated armor components.[13] Similarly, Italian bascinets from around 1400, such as those recovered from Venetian outposts, included steel visors pivoted to the skull with slots for sight and breath, underscoring the design's prevalence across Europe.[14]

Visored helmets played a critical role in the Hundred Years' War (1337–1453), where they equipped knights and men-at-arms against the era's prevalent threats, including longbow arrows and close-quarters melee weapons like swords and polearms.[15] The bascinet with its visor, often paired with a mail aventail for neck protection, served as the standard headgear for much of the conflict, as seen in French and English forces at battles like Agincourt in 1415, providing essential face defense without fully encumbering mobility. Toward the war's later phases, the sallet—a successor to the bascinet with an integrated, sometimes pivoting visor—emerged, offering enhanced coverage against the increasing use of edged weapons and early firearms.[11] By the late 15th and into the 16th century (roughly 1500–1575), visors evolved further in Renaissance plate armor, particularly in German and Austrian designs, where elaborate mask-like forms became fashionable. These often featured embossed human or grotesque faces for both added protection and psychological intimidation on the battlefield.[5] This military innovation in visored designs later influenced civilian headwear adaptations for shading and protection.[16]

Evolution in Headwear

The transition of visors from military protection to civilian sun-shading accessories began in the 19th century, evolving into everyday headwear focused on comfort and utility rather than combat defense. Originating as metal face guards in medieval helmets to safeguard warriors' eyes and faces, the visor concept adapted into softer, non-armored forms for recreational and sporting use.

Visors first emerged in civilian headwear during the 1860s through baseball uniforms, when the amateur Brooklyn Excelsiors team adopted wool caps featuring stiff visors to shield players' eyes from sunlight during outdoor games.[17] This design marked a shift toward practical eye protection in sports, with the stiff brim providing essential shade without obstructing peripheral vision. By the early 20th century, key milestones advanced visor construction; in 1903, Spalding Manufacturing introduced the first stitched visors on baseball caps, creating a more durable and standardized feature that extended the brim's lifespan under regular use.[17] Materials also progressed from heavy wool crowns and rigid brims—occasionally reinforced with leather-like stiffeners—to lighter fabric blends, improving breathability and comfort for extended recreational activities.[18]

Further innovations in the 20th century led to standalone visor hats, detached from full crowns for enhanced ventilation. These emerged in the early 20th century for equestrian pursuits and golf, consisting of a brim secured by a headband without enclosing the head, allowing air circulation during physical exertion.[8] By the 1920s, visors permeated broader fashion trends, particularly influenced by tennis, where lightweight and adjustable designs appealed to both athletes and casual wearers seeking stylish sun protection.[19] This cultural adoption transformed visors from niche sporting gear into versatile accessories, emphasizing portability and adaptability in everyday civilian attire.

Invention and Early Adoption

The automotive sun visor emerged in the early 1920s as a practical solution to the challenges of driving amid intense sunlight glare, particularly on the unpaved roads common at the time. In 1924, inventor Hathaway developed the first such device, known as a "glare shield," which was mounted externally on the Ford Model T to shield drivers' eyes from direct sunlight.[20] This innovation was influenced briefly by shading concepts from headwear visors, adapting them for vehicular use. The design addressed growing concerns over eye strain, exacerbated by post-1910s advancements like the widespread adoption of glass windshields and increasing vehicle speeds on dusty, unshaded roadways.[7]

Early adoption accelerated with the transition to internal visors for better accessibility and integration. By 1931, Ford began incorporating fabric-covered internal sun visors on select Model A vehicles, such as the Victoria, marking a shift from external mounts to more convenient interior placements using simple metal frames upholstered in fabric.[21] In the late 1920s, luxury manufacturer Packard introduced the first pull-down interior visor on its high-end models, allowing drivers to adjust shading more easily without leaving the cabin. These initial materials—primarily stamped metal for structure and basic fabric or leather coverings—prioritized durability and cost-effectiveness over aesthetics.[21]

By the 1930s, sun visors had become a standard feature on most U.S.-made automobiles, reflecting their proven role in enhancing driver safety and comfort amid expanding highway networks and higher travel speeds. Patents from the era, such as those detailing adjustable hinge mechanisms, further refined the basic design for smoother deployment and positioning. This rapid integration underscored the visor's evolution from a novel accessory to an essential component in automotive engineering.[7]

Design Advancements

Following World War II, automotive sun visor designs began incorporating lighter materials to improve usability and reduce headroom intrusion. In the 1950s, manufacturers like Ford introduced foam cores, such as latex or early urethane variants, as optional features to replace heavier fiberboard constructions, enabling slimmer profiles while maintaining structural integrity.[22] By the 1960s, functionality expanded with the addition of vanity mirrors on models including the Ford Mustang, providing passengers with personal grooming aids integrated into the visor body; illuminated versions, using simple electric bulbs, appeared as premium options to enhance visibility in low light.[23]

Material advancements in the 1970s focused on safety and durability, shifting from traditional fabric and vinyl coverings over rigid cores to energy-absorbing foams and emerging plastics like polycarbonate for select components, which offered shatter resistance during impacts. These changes aligned with the introduction of Federal Motor Vehicle Safety Standard (FMVSS) No. 201 in 1972, effective for new vehicles from 1973, which mandated that sun visors for front outboard seating positions be constructed of or covered with energy-absorbing material to limit head injury criteria (HIC) in crashes.[24] Dual-zone configurations, allowing independent adjustment and positioning for driver and passenger visors, became more prevalent to customize glare blocking without compromising the other's view.[25]

The 1990s brought further refinements for compatibility with advancing safety systems, particularly airbag deployment. Visor designs were engineered to minimize interference, using flexible hinges and tear-away fabrics to prevent the visor from becoming a projectile or obstructing inflation paths during frontal impacts, as emphasized in NHTSA guidelines for occupant protection.[26]

In the 2020s, innovations like Bosch's Virtual Visor represent a shift toward smart technology, employing a driver-facing camera with AI to detect eye position and a transparent LCD panel that selectively darkens only the glare-affected area, blocking sun rays without obscuring the forward view.[27] This builds on foundational glare shields from the 1920s while prioritizing unobtrusive functionality.

Team Sports Applications

Visors have played a significant role in team sports since the late 19th century, primarily aiding players in maintaining visibility under bright conditions while integrating team branding into uniforms. In baseball, extended brims on caps were introduced in the 1860s, when the Brooklyn Excelsiors adopted a rounded-top cap with a long peak designed specifically for sun shading during outdoor games.[28] This early design addressed the challenges of daytime play, allowing fielders and batters to track the ball without excessive glare.

By the 1920s–1930s, baseball caps were typically constructed from wool for added durability and structure, fitting seamlessly into team uniforms as a standard accessory. These models evolved in the 1980s with the incorporation of mesh panels in the crown and back, enhancing breathability and comfort during extended innings in hot weather. Modern Major League Baseball (MLB) caps feature adjustable designs with embroidered team logos.[29]

Design features of sports visors emphasize functionality, such as curved brims that provide shade without obstructing peripheral vision, enabling players to monitor teammates and opponents effectively.[30] Regulations govern visor use to ensure fairness; for instance, the National Collegiate Athletic Association (NCAA) mandates that eye shields remain clear or nearly clear—as of 2025, allowing "nearly clear" options—limiting tint levels to over 90% visible light transmission and preventing any unfair visibility advantages.[31][32]

In American football, eyeshields—transparent visors attached to helmets—emerged in the 1980s to protect against impacts and reduce glare, marking a shift toward integrated head protection. The National Football League (NFL) initially permitted tinted versions in the 1980s and 1990s but banned dark tints in 1998 for safety and visibility concerns among officials; lightly tinted options were reapproved in 2019 through a partnership with Oakley. Ice hockey goalies adopted clear visors on masks starting in the 1950s, with minor-league players using plastic shields for facial protection while preserving sightlines; this culminated in Jacques Plante's landmark 1959 NHL debut of a full protective mask, influencing team-wide standards. These applications reflect broader advancements in headwear, adapting protective elements from industrial designs to athletic needs.[33][34]

Individual Sports Uses

In individual sports such as golf and tennis, visors have long provided essential shading and comfort without restricting movement. Visors for active pursuits including golf emerged in the early 20th century, allowing players to shield their eyes from the sun while maintaining visibility on the course.[8] Early designs incorporated sweatbands to absorb perspiration during prolonged outdoor play.[35] In tennis, visors emerged as a fashion accessory in the 1920s, offering a lightweight alternative to full hats for players on sun-exposed courts.[36]

For cycling and running, clip-on visors gained popularity from the 1970s onward, prized for their aerodynamic profile and ability to provide targeted shading without adding bulk.[35] These models, often secured with elastic bands, help prevent sweat from dripping into the eyes during intense efforts like marathons, enhancing focus and endurance for solo athletes. In both disciplines, visors prioritize mobility, with crownless constructions promoting airflow to keep the head cool under exertion.

Key design features emphasize functionality for individual use: crownless styles facilitate ventilation, while UV-protective coatings block 100% of UVA and UVB rays to safeguard skin and eyes during extended exposure.[37] Brands like Nike introduced ventilated visors in the 1990s, featuring perforations for breathability that became staples in golf and tennis gear.

The evolution of sports visors reflects advancing materials and technologies tailored to solo activities. From simple fabric constructions in the 1920s, designs progressed with improved shading innovations, building on developments from team sports, underscoring visors' role in enhancing performance through lightweight, adaptive protection.[38]

Industrial and Welding Contexts

In industrial settings, visors serve as critical components of personal protective equipment (PPE) to shield workers from hazards such as flying debris, sparks, and intense light sources. Early designs in the 1910s consisted of hand-held shields, often made from basic materials like leather or metal frames with glass lenses, providing rudimentary protection during arc welding tasks.[39][40] These shields evolved into full helmets by the 1930s, with the introduction of green-tinted glass filters specifically for arc welding to attenuate harmful ultraviolet and infrared radiation while allowing visibility of the weld pool.[41]

Welding helmets incorporating flip-up visors became standard post-1930s, transitioning from fixed opaque shields to adjustable designs that balanced protection with usability. Materials advanced from leather and metal in the early 1900s, which offered durability but limited comfort, to impact-resistant plastics like fiberglass composites by the 1950s, enhancing lightweight protection against impacts and heat.[39][42] A significant innovation occurred in the 1980s with the commercialization of auto-darkening filters (ADF) using liquid crystal technology, pioneered by Swedish manufacturer Hornell (Speedglas), which automatically adjusts lens darkness from shade 9-10 in light state to shades 10-13 during welding arcs for optimal eye safety.[39][43] These ADF visors, typically rated for shades 10-13 in shielded metal arc welding, reduce the risk of arc eye by instantly blocking intense light while improving workflow efficiency over manual flip mechanisms.[44][45]

Beyond welding, face shields are essential in construction and machining, where they protect against flying particles and chemical splashes. The Occupational Safety and Health Administration (OSHA) established standards for eye and face protection in the 1970s under 29 CFR 1926.102 for construction, mandating shields that provide side protection and comply with impact resistance requirements to safeguard against hazards like debris from tools or machinery.[46] Modern industrial visors, primarily constructed from polycarbonate since the late 1970s, offer high impact resistance—capable of withstanding drops from 50 inches or high-velocity particles—while remaining lightweight and transparent.[47][48]

The ANSI/ISEA Z87.1 standard, first published in 1968 and updated periodically, governs impact resistance for face shields, requiring them to pass drop-ball and high-velocity tests to ensure no penetration or shattering under industrial stresses.[49] In machining applications, such as grinding or milling, visors often feature anti-fog coatings to maintain clear visibility in humid or high-heat environments, preventing condensation that could obscure hazards.[50][51] These coatings, applied to polycarbonate surfaces, enhance usability without compromising the material's inherent resistance to scratches and impacts.[52]

Medical and Emergency Applications

In medical settings, protective visors, often referred to as face shields, serve as essential personal protective equipment (PPE) for healthcare workers, including physicians, nurses, and dentists, to shield the face, eyes, and mucous membranes from splashes, sprays, and droplets of bodily fluids during procedures such as surgeries, examinations, and patient care.[53] These devices provide a transparent barrier that covers a larger facial area than goggles or surgical masks alone, reducing the risk of exposure to infectious pathogens like influenza or other respiratory viruses.[53] Studies have demonstrated their efficacy, with one experiment showing face shields reducing inhalational exposure to influenza aerosols by 96% at 18 inches and 92% at 72 inches from the source.[54] When combined with N95 respirators, they further prevent contamination of the eyes, nose, and mouth, enhancing overall infection control without requiring fit testing or causing significant fogging.[55]

In emergency medical services (EMS), visors are critical for first responders and paramedics during high-risk interventions, such as cardiopulmonary resuscitation (CPR), trauma assessments, or handling infectious cases in ambulances and accident scenes, where exposure to blood, vomit, or aerosols is common.[53] Their lightweight, adjustable designs allow for quick donning and doffing in fast-paced environments, and they can be easily disinfected between uses, extending the usability of other PPE like masks.[53] During the COVID-19 pandemic, visors were widely adopted in emergency departments as an adjunct or alternative to masks, though evidence indicates they are less effective against airborne transmission alone and should be paired with respirators for optimal protection.[56]

Beyond standard protective uses, specialized visor-like devices have emerged for diagnostic purposes in emergency care. The Cerebrotech Visor, a portable, non-invasive tool cleared by the FDA in 2018, uses low-power radio waves to detect hemispheric bioimpedance asymmetry indicative of ischemic strokes, enabling rapid assessment in under two minutes at the bedside or in ambulances.[57] Clinical trials, such as the VITAL II study, validated its accuracy in identifying large-vessel occlusions, with applications extending to monitoring cerebral edema and traumatic brain injuries in emergency settings.[58] This device supports timely interventions like thrombolysis, potentially improving outcomes in time-sensitive neurological emergencies.[59]