Geometric & Theoretical Optics I: Object Image Relationship

Flashcards covering key definitions and concepts related to basic image formation, pinholes, shadows, real and virtual objects/images, lenses in series, and clinical applications in geometric and theoretical optics.

Blurred Illumination (no aperture)

The result when a screen captures light from an object without an aperture, yielding blur circles and no detailed image.

Blur Circles

Circular areas of light captured on a screen when light from object point sources diverges without an aperture, causing a blurred image.

Aperture

A device used in optics to focus an image on a screen by blocking peripheral rays originating from an object.

Pinhole Effect

The phenomenon where an extremely small aperture allows only one ray from each object point to pass, creating a clear but dim image.

Diffraction

The scattering of light as it interacts with the edges of an aperture, which sets a practical limit on how small an aperture can be.

Pupils (in the eye)

The natural aperture of the eye that limits peripheral rays from entering, contributing to image clarity.

Iris

The colored part of the eye that blocks peripheral rays from reaching the retina, resulting in a smaller diameter blur circle.

Clinical Use of Pinhole (PH)

A diagnostic tool used to determine if decreased visual acuity is due to a refractive error (vision improves) or an underlying eye disease (vision typically does not improve substantially).

Shadow

In the context of shadows, the darkened area created by an opaque object blocking light from a light source, serving as an 'image'.

Real Object

A source of divergent light waves that are incident on an optical system, typically located anterior to the system.

Physically Real Object

A type of real object that emits diverging rays that are not interfered with before reaching an optical system.

Optically Real Object

A type of real object that emits diverging rays that are interfered with on their way to an optical system, such as the image formed by a preceding lens in a series.

Virtual Object

A source of convergent light waves incident on an optical system, which is not naturally occurring and typically requires a preceding convergent lens to create it.

Real Image

An image formed when convergent light exits an optical system, capable of being captured on a screen and typically located posterior to the lens.

Physically Real Image

A type of real image formed by convergent light that is not subjected to further interference after exiting an optical system.

Optically Real Image

A type of real image created by convergent light that is interfered with by another optical element shortly after exiting a system, before the image can fully form.

Virtual Image

An image formed when divergent light exits an optical system, which cannot be captured on a screen and whose location is determined by extrapolating the diverging rays backward.

Solid Rays

Graphical representations indicating the actual trajectory of light rays as they pass through a medium or optical system.

Dash Rays

Graphical representations used to indicate virtual or optically real light paths, typically for extrapolated rays or intermediate images in a series of optical elements.

Lenses in a Series

An arrangement where the image formed by one lens acts as the object for the subsequent lens in the optical system.

Principle of Reversibility

A principle stating that if the direction of light is reversed, its original path through an optical system can be retraced, with the previous object becoming the image and vice versa.

Conjugate Points

Two points in an optical system that are intrinsically linked, where one point serves as the object and the other as its corresponding image; if one moves, the other also moves.

Emmetropia

The condition of having the ideal optical power in the eye, allowing light from distant objects to focus precisely on the retina without accommodation.

Accommodation (Young Eyes)

The process by which the lens of a young eye changes shape (becomes more convex/convergent) to increase its refractive power and focus on near objects.

Presbyopia

An age-related condition where the eye's natural lens loses its ability to accommodate for near vision, often requiring converging (plus) lenses for correction.

Myopia

A refractive error where the eye possesses too much convergent power, causing light to focus anterior (in front) of the retina, resulting in blurred distant vision.

Far Point (Myopia)

The most distant object point that can be clearly seen by a relaxed myopic eye without corrective lenses, being conjugate with the retina.

Hyperopia

A refractive error where the eye does not have sufficient power, causing light from distant objects to focus posterior (behind) the retina, resulting in blurred near vision and sometimes distant vision.

Hyperopic Shift

A condition where the retina shifts anteriorly (forward), making the eyeball effectively shorter, which typically causes the image to land posterior to the retina.

Myopic Shift

A condition where the retina shifts posteriorly (backward), making the eyeball effectively longer, which typically causes the image to land anterior to the retina.