Augmented reality (AR) has been a focal point since its emergence in the 1960s, with optical combiners, particularly waveguides, playing a crucial role in overlaying digital information onto the real world. Waveguides are favored for their compact design and large eyebox, essential for human-centric technology. However, they face challenges in meeting the requirements of the human visual system. This paper highlights recent advancements and future perspectives of AR technology. Waveguide combiners use total internal reflection (TIR) to guide light, enabling simultaneous viewing of the real world and digital information. The waveguide's design allows for expansion of the eyebox without compromising the full field-of-view (FOV), increasing the system's etendue at the expense of brightness. Ding et al. reviewed AR waveguide displays, emphasizing the ambient contrast ratio (ACR), which depends on the light engine and display's luminance. High-brightness light engines and efficient waveguides are crucial for high ACR under bright ambient conditions. Additional metrics like resolution density and frame rates are also important for image quality. Waveguide combiners can be geometric or diffractive, depending on whether they use reflection/refraction or diffraction. Geometric waveguides use embedded mirrors or prisms, while diffractive waveguides use components like surface relief, holographic, or metasurface gratings. K-vector diagrams are valuable tools for understanding waveguide systems, showing the maximum FOV that can be contained within the waveguide. These diagrams help in analyzing the behavior of light in different systems and designing intricate pupil expansion schemes. Ding et al. also discussed the importance of advanced metrics for evaluating waveguide performance, such as efficiency maps over the FOV and eyebox. These maps help in understanding how efficiency varies with eye position and can reveal which fields or eyebox positions have the worst performance. Summarizing waveguide performance as a single-value metric, such as the minimum efficiency over the FOV, can effectively capture the display's capabilities. Ongoing research into waveguide components reveals how they set limits and tradeoffs for system performance. Future waveguide research will benefit from a thorough understanding of how each component impacts performance and the ability to communicate these findings comprehensively.Augmented reality (AR) has been a focal point since its emergence in the 1960s, with optical combiners, particularly waveguides, playing a crucial role in overlaying digital information onto the real world. Waveguides are favored for their compact design and large eyebox, essential for human-centric technology. However, they face challenges in meeting the requirements of the human visual system. This paper highlights recent advancements and future perspectives of AR technology. Waveguide combiners use total internal reflection (TIR) to guide light, enabling simultaneous viewing of the real world and digital information. The waveguide's design allows for expansion of the eyebox without compromising the full field-of-view (FOV), increasing the system's etendue at the expense of brightness. Ding et al. reviewed AR waveguide displays, emphasizing the ambient contrast ratio (ACR), which depends on the light engine and display's luminance. High-brightness light engines and efficient waveguides are crucial for high ACR under bright ambient conditions. Additional metrics like resolution density and frame rates are also important for image quality. Waveguide combiners can be geometric or diffractive, depending on whether they use reflection/refraction or diffraction. Geometric waveguides use embedded mirrors or prisms, while diffractive waveguides use components like surface relief, holographic, or metasurface gratings. K-vector diagrams are valuable tools for understanding waveguide systems, showing the maximum FOV that can be contained within the waveguide. These diagrams help in analyzing the behavior of light in different systems and designing intricate pupil expansion schemes. Ding et al. also discussed the importance of advanced metrics for evaluating waveguide performance, such as efficiency maps over the FOV and eyebox. These maps help in understanding how efficiency varies with eye position and can reveal which fields or eyebox positions have the worst performance. Summarizing waveguide performance as a single-value metric, such as the minimum efficiency over the FOV, can effectively capture the display's capabilities. Ongoing research into waveguide components reveals how they set limits and tradeoffs for system performance. Future waveguide research will benefit from a thorough understanding of how each component impacts performance and the ability to communicate these findings comprehensively.