Introduction to Contact Lenses - Lecture Flashcards

Flashcards covering key concepts from the lecture notes on introduction to contact lenses, including history, material and design classifications, modern lenses, and common terminologies.

What is a contact lens?

A thin lens considered to be a medical device placed directly on the surface of the eye to correct vision.

Who first described the concept of a contact lens that comes into contact with the eye?

Leonardo da Vinci (1508).

Which scientist described a glass contact lens designed to match the shape of the eye?

John Herschel (1827).

Who fitted a blown glass lens to the eye of a patient whose eye had been surgically removed in 1887?

F.E. Mulle.

Who described the first contact lens intended to correct vision?

A. E. Fick (1888).

When were the first plastic scleral contact lenses constructed and by whom?

Muller and Obrig (1938).

Who designed and fitted glass corneal contact lenses in the 1940s?

E. Kalt.

Who made the first plastic corneal lens from PMMA in 1947?

Kevin Touhy.

Who developed HEMA for contact lenses?

Otto Wichterle.

Name the two broad material categories for contact lenses.

Hard and Soft.

Name two soft contact lens material families.

Hydrogel and Silicone hydrogel.

List the common designs for lenses (according to design).

Monocurve, Bicurve, Tricurve, Aspheric.

What is Ortho-K in modern contact lenses?

Gas-permeable contact lenses that temporarily reshape the cornea to reduce refractive errors.

What is a hybrid contact lens?

A large-diameter lens with a rigid gas permeable central zone and a soft or silicone hydrogel peripheral zone.

What is a wink activated telescope contact lens?

A 1.55 mm-thick lens with a reflective telescope activated by winks, providing magnification (2.8x) when winked.

What is the Google contact lens?

A prototype that monitors glucose levels in tears.

What is the SENSIMED Triggerfish contact lens?

A soft disposable silicone lens embedding a micro-sensor that measures intraocular pressure.

What is the iOptik contact lens?

Enhances vision and enables visualize digital content; light from a display passes through the center of the pupil while ambient light passes through the outer portion, producing a superimposed image.

What is Terminator Eyes contact lens?

A lens that projects road directions or text messages from a smartphone straight to the eye.

What is Base Curve (BC) in lens terminology?

Radius of curvature of the posterior zone.

What is the Optic Zone (OZ)?

Posterior central optic portion of the lens; indicates the size of the visually usable portion.

What is the Lens Diameter (LD)?

The maximum external dimension of a lens.

What is the Posterior Peripheral Curve Radius (PPCR)?

Radius of the peripheral curve.

What is the Peripheral Curve Width (PCW)?

Width of the posterior peripheral curve portion of the lens.

What is the Sagittal value (sag)?

Distance from the line drawn between the outer edges of the lens to the center of the back surface.

What is the Optic cap (OC)?

Central anterior optic portion of a lens.

What is the Optic cap radius (OCR)?

Radius of the central anterior optic portion.

What is the Anterior Peripheral Curve Zone (APCZ)?

Anterior peripheral or lenticular portion of the lens.

What are visibility tints used for?

Improve handling and visibility against the eye, especially on light-colored eyes.

What is an opaque tinted lens?

Lenses that can change the apparent color of the eye by masking the original color.

What is a combination tint?

A mix of transparent and opaque tint to blend eye color with the lens color.

What is a therapeutic (bandage) lens?

Used to promote healing for a variety of corneal diseases.

What are presbyopic correction options in contact lenses?

Monovision, bifocal soft lenses, alternating vision, and simultaneous/multifocal designs.

What is monovision?

One eye is fitted for distance vision and the other eye for near vision.

What is a bifocal soft contact lens?

A lens with separate zones for distance (top) and near (bottom) vision.

What is a multifocal contact lens?

Lenses with multiple focal zones to provide both distance and near vision.

What is a spherical contact lens?

A lens designed to correct spherical refractive errors (no cylindrical power).

What is a toric contact lens?

A lens designed to correct significant astigmatism.

What does the correction range -20.00D to +20.00D refer to?

The available correction range for spherical lenses.