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CONTACT LENS > Random CL questions 2 > Flashcards

Random CL questions 2 Flashcards

1
Q

a combination solution for rigid contact lenses that contains both wetting agents and disinfecting chemicals

A

Wetting & Soaking solution

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2
Q

Silicone and oxygen are made into a siloxane which is then copolymerized with PMMA to create an oxygen permeable material used in the manufacture of rigid lenses

A

Siloxane/Silicon Acrylates

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3
Q

Vision that is temporarily distorted or out of focus when a contact lens wearer, particularly a rigid contact lens wearer, switches from contact lens to glasses.

The blur may be caused by corneal edema, mechanical molding, or a combination of two

A

Spectacle Blurr

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4
Q

a mercury compound, used as a preservative in some contact lens solutions, that has been implicated as the cause of many red eyes and other adverse reactions in contact lens wearers

A

Thimerosal

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5
Q

retention of fluorescein dye by damaged corneal tissue

A

Corneal staining

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6
Q

a substance that enables tears to spread evenly over the surface of a rigid contact lens and helps to cushion the lens on insertion

A

Wetting agent

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7
Q

a detergent-like cleaner that emulsifies debris and removes foreign substances from the surfaces of a contact lens

A

Surfactant Cleaner

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8
Q

the pumping in of fresh, oxygenated tears between the contact lens and the cornea and the pumping out of deoxygenated tears and metabolic wastes with each blind

This is necessary to maintain normal corneal metabolism

A

Tear Exchange

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9
Q

the process of reducing the number of viable micro-organisms to a level which is harmful neither to ocular health nor the quality of contact lenses and accessories

A

Disinfection

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10
Q

the date, designated by the manufacturer, beyond which a product should not be first used

A

Expiry Date

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11
Q

Inflammatory cells within the cornea occurring as a response to viral or other infection, toxic or chemical stimulus

Typically seen as greyish disciform patches near the limbus

A

INFILTRATES

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12
Q

a storage solution used to enhance the biocompatibility of RGP lens surfaces

A

Conditioning Solutions

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13
Q

agent intended to prevent the growth of micro-organisms in a care product

A

Preservatives

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14
Q

soft contact lens used to protect the cornea, reduce pain and assist healing in conditions such as bullous keratopathy, ulcers and burns

A

Therapeutic CL (for aniridia) / Bandage CL

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15
Q

Hydrogel lens prior to hydration:

A

Xerogel

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16
Q

Lens design consisting of the central radius and two peripheral curves

A

Tricurve

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17
Q

Fitting technique where the BOZR is selected to be parallel to the corneal surface

A

Parallel fit / Alignment Fit

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18
Q

Lens design consisting of the central radius and multiple peripheral curves

A

Multicurve

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19
Q

angle formed by a tangent to a sessile drop of fluid at the point where the drop meets a surface.

a more wettable material has a smaller angle of contact

the angle is zero for a completely hydrophilic material

A

Contact Angle

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20
Q

irregularity in the size of cells of the corneal endothelium

observed in extended wear and in long-standing PMMA wearers

A

Polymegathism

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21
Q

Method of soft lens manufacture employing heat and closed moulds

A

Cast molding

22
Q

a contact lens fitting, usually steep, in which there is a proof of tears between the back surface of a hard lens and the anterior surface of the corneal apex

generally observed with fluorescein

A

Apical Clearance / Pooling

23
Q

the time in seconds for the break up of the precorneal tears film in a non-blinking eye

generally observed with fluorescein and the slit lamp

A

TBUT

24
Q

small vesicles in the corneal epithelium containing fluid and cellular debris

occurs as a typical response to corneal stress, particularly extended wear

A

Microcyst

25
Q

staining of the nasal and temporal areas of the peripheral cornea

Frequently associated with conjunctival injection in the horizontal meridian

Influenced by dry eyes, poor blinking, lens design and lens material

A

3 & 9 o’clock Staining

26
Q

distance between a point on the back surface of a lens at a specified diameter and the continuation of the back central optic zone

Measured along a radius of curvature of the latter

A

Radial edge shape

27
Q

a contact lens fitting, usually flat, in which the back surface of the lens rests on the apex of the cornea

Generally observed with fluorescein

A

Apical Touch

28
Q

a solution having the same tonicity as 0.9% sodium chloride

A

Isotonic Solution

29
Q

the shaping of a lens, normally with a straight edge to assist with correct orientation on the eye in Toric or bifocal fitting

A

Truncation

30
Q

the formation of trapped air bubbles beneath a contact lens

usually associated with hard lenses but can also occur with soft lenses

A

Dimpling

31
Q

the thickness of the layer of tears between the back surface of a contact lens and the front surface of the cornea

A

Tear Layer

32
Q

Technique for correcting presbyopia in which reading addition is incorporated into the contact lens for the non-dominant eye

A

MonoVision

33
Q

achieved with a bifocal contact lens which positions both distance and reading portions in front of the pupil at the same time

A

Simultaneous Vision / Multifocal

34
Q

Lens design where part of all of the back surface is of toric construction

the front surface may be either spherical or toroidal in which case it is a bitoric

A

Back Surface Toric

35
Q

The reduction, modification or elimination of a visual defect by a programmed application of contact lenses

The technique for reducing myopia consists of changing the shape of the cornea by fitting a series of hard lenses progressively flatter than “K”

Also called corneal refractive therapy (CRT) and Overnight vision correction (OVC)

A

Ortho-K / OrthoKeratology

36
Q

achieved with a bifocal contact lens which has distinct zones for distance and near

The lens must translate for the different portions to line up with the pupil area for the appropriate visual task

The reading segment may be either fused or solid and only hard lenses have only proved successful

A

Alternating Vision

37
Q

Soft lens materials made from a combination of silicone rubber and hydrogel monomers

A

Silicon Hydrogel

38
Q

Translucent or opalescent dimples containing cellular debris trapped behind a contact lens

Most often associated with silicone hydrogels and sometimes known as lipid plugs or pre-corneal deposits

A

Mucin Balls

39
Q

Lens design consisting of the central radius and one peripheral curve

A

Bi-Curve

40
Q

Methods used to measure the stability of the tears film without a staining agent

employing a cold diffuse light source or grid pattern for observation

A

NITBUT

41
Q

Loss of tolerance to contact lenses from long-term hypoxia resulting in chronic oedema

A

Corneal Exhaustion Syndrome / Intolerance

42
Q

Method of soft lens manufacture employing liquid polymer spun to the required shape in rotating open moulds

A

Spin Casting

43
Q

Extreme, painful response to gross corneal edema as a result of excessive contact lens wear

usually found with PMMA and typically occurring in the middle of the night

A

Over Wear Syndrome

44
Q

The smoothing of a lens transition with a curve intermediate between the two radii

Blending may be light, medium or heavy

A

Blending

45
Q

A lens where the second radius is steeper than the base curve

Such lenses are used mainly for orthokeratology but also for other fitting applications such as corneal grafts and post refractive surgery

A

Reverse Geometry

46
Q

a contact lens which fits over both the cornea and bulbar conjunctiva

Typical overall sizes are 22-24mm

A

Scleral Lens

47
Q

a small disc made of various silicone and or various silicone and or plastic materials usually containing an optical correction which is worn over the cornea as an alternative to spectacles which can correct ametropias and presbyopia

A

Contact Lens

48
Q

Contact Lens manufacturing method in which dry buttons of the lens material are cut with lathes

most labor intensive and least reproducible method of contact lens manufacture, but useful for production of small quantities or custom parameters

A

Lathe Cutting

49
Q

a discontinuity or break in the epithelial tissue of thecornea associated with inflammation in the cornea that could be sterile or may be caused by bacterial, fungal or viral infection

A

Corneal Ulcer

50
Q

a discontinuity or break in the epithelial tissue of the cornea associated with inflammation in the cornea that could be sterile or may be caused by bacterial, fungal or viral infection

A

Corneal Ulcer

51
Q

The amount of oxygen diffusing through a given amount of lens material in a give amount of time, under specified testing conditions

A

Oxygen Permeability

CONTACT LENS (10 decks)

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