Optics2 Exam 1- HW #1

What type of eye structure does a honeybee possess?

Compound eyes

How does the nautilus eye differ from the human eye?

It has a pinhole filled w/ seawater

In goldfish eyes, where does most of the optical power reside?

Lens

What feature characterizes swordfish eyes?

Large size

What is a key advantage of human eyes over compound eyes?

Large aperture for light capture

Who was the first to suggest the gradient index in the human lens?

Thomas Young

What is the primary optical function of the human eye?

Light focusing

What does the term "paraxial approximation" refer to in optics?

Small-angle approximation

What is the main purpose of eye models?

To stimulate optical properties and refractive errors

How many refracting surfaces does the Gullstrand-Emsley model have?

Three

What is a characteristic of reduced eye models?

Single refracting surface

What is the Emsley model best used for?

Understanding refractive errors

What is a feature of the Le Grand full theoretical eye model?

Four refracting surfaces

What is the significance of cardinal points in eye models?

They help calculate image position and size

How does the refractive index in the crystalline lens change?

Increases from edge to center

What is a gradient index lens?

Lens with varying refractive index

How are customized eye models beneficial?

They account for individual differences

What do paraxial models of the eye typically ignore?

Higher-order aberrations

How do eye models assist in intraocular lens design?

By predicting retinal image size

What is the function of nodal points in optical models?

They allow to ray trace a light that does not deviate

What is the main limitation of single refracting surface models?

Lack of accommodation simulation

Which optical model is preferred for refractive error calculations when corrected with glasses?

Emsley model

What is the purpose of using models with a lens structure?

To account for gradient index

What feature of the eye is crucial for focusing light accurately?

Cornea and lens curvature

What is the Gullstrand number 2 eye model used for?

Accommodation and refractive error calculations

How does the eye's optical system primarily achieve autofocus?

Through lens shape changes

What do the principal planes (H and H') of the eye indicate?

Anterior and posterior principal planes

How does the axial length of the eye affect refractive errors?

Longer eyes cause myopia

What is the purpose of ray tracing in optical models?

To calculate image formation

What does the term "emmetropization" refer to?

The process of achieving perfect focus in the eye

How is the refractive index in the lens related to its gradient?

It varies from edge to center

How does the eye maintain focus of approaching objects?

By adjusting lens shape and position

What is the purpose of using schematic eye models?

To simplify complex optical calculations

How does accommodation change with age?

It decreases

How do nodal points assist in optical calculations?

They provide reference points for ray tracing

How do optical models aid in the design of intraocular lenses?

By predicting refractive power and image size

How does the eye's optical system achieve autofocus?

Through lens accommodation

How is accommodation modeled in optical systems?

By adjusting lens shape and position

What is the main benefit of using gradient index lenses in models?

More accurate representation of the optical properties of the crystalline lens

What is the primary limitation of single refracting surface models?

Inability to simulate accommodation

What is the definition of visual acuity?

Smallest detail resolvable by the eye

What does a Snellen chart measure?

Visual acuity

What is the most commonly used visual acuity scale in the US?

20/20 scale

What does a 20/40 visual acuity indicate?

Worse than normal vision

How is logMAR visual acuity expressed?

As the result of a logarithmic operation

What is the function of contrast sensitivity in vision?

Measures ability to detect differences in luminance

What does the Minimum Angle of Resolution (MAR) describe?

Smallest detail resolvable by the eye

How can you measure contrast sensitivity?

Pelli-Robson chart

What condition is indicated by a visual acuity of 20/200 or less?

Legal blindness

What does a decimal visual acuity of 1 indicate?

Normal vision

What is the purpose of the Jaeger scale?

Measures near visual acuity

What does the Rayleigh criterion define?

Minimum resolvable detail

How does pupil size affect visual acuity?

Smaller pupils can increase diffraction;

Smaller pupils typically improve acuity

What does the term "diffraction-limited" refer to?

Resolution limited by diffraction

What is the role of the point spread function (PSF) in vision?

Describes the response of an optical system to a point source

How does age affect accommodation in the eye?

Accommodation decreases with age

What does the term "legal blindness" refer to?

Vision loss large enough to qualify for benefits

How is contrast threshold defined?

Smallest contrast required to see a target

What is the effect of astigmatism on vision?

Causes blurred vision

What is the function of the field of view in vision?

Determines useful vision area

What is the effect of a larger pupil on visual acuity?

Decreases acuity due to aberrations

What role does the Nyquist limit play in vision?

Defines upper resolution limit as defined by the packing of photoreceptors

Link the number of surfaces of the eye model with their use: One refracting surface

Refraction for Glasses

Link the number of surfaces of the eye model with their use: Two refracting surfaces

Contact lens adaptation (no keratoconus)

Link the number of surfaces of the eye model with their use: Three refracting surfaces

Lasik surgery

Link the number of surfaces of the eye model with their use: Six refracting surfaces

Design of an Accommodating IOL

Which is the oldest human schematic eye shown in class that explains accommodation?

Descartes' eye model

Imagine that you are designing a new model of contact lens, while working on this project which is the minimun number of surfaces that your schematic eye should have?

3

Imagine now that you are designing a new algorithm for lasik, while working on this project which is the minimun number of surfaces that your schematic eye should have?

3

What is the modulation transfer function?

Ratio between the contrast of the image (numerator) and the object (denominator) as a function of the frequency

Does astigmatism affect equally to both principal meridians of the modulation transfer function?

No

Does the curvature of the cornea increase the field of view (with respect to a flat cornea)?

Yes