LDO Review Contacts
Quiz yourself by thinking what should be in
each of the black spaces below before clicking
on it to display the answer.
Help!
|
|
||||
|---|---|---|---|---|---|
| The central posterior curve is also known as what? | Base curve and optical zone
🗑
|
||||
| The back surface of the lens that has the base curve ground into it and is used for the fitting and power is called what? | Optical Zone
🗑
|
||||
| What lies between the base curve and the peripheral curve on the posterior lens surface? | Secondary curve or intermediate curve
🗑
|
||||
| What is the outermost curve on the posterior lens surface? | Peripheral curve
🗑
|
||||
| What is the treatment given to the sharp junctions between the base curve, secondary curve, and peripheral curve? | Blending
🗑
|
||||
| the overall width of the lens from one edge to the other and is measured in mm is called what? | Diameter
🗑
|
||||
| what is the measurement taken from the anterior surface to the posterior surface of the lens at its geometric center? | Center thickness
🗑
|
||||
| What is the curvature that determines the lens power? | Anterior optical zone radius
🗑
|
||||
| The difference between the radii of the anterior and posterior lens surfaces creates what? | Lens power
🗑
|
||||
| What does lenticular flange do to a contact lens? | Aid in lens positioning by increasing or decreasing edge thickness
🗑
|
||||
| When a contact lens sits low on the cornea would you increase or decrease the edge thickness? | Increase
🗑
|
||||
| When angulation is placed on the front surface of a lens to reduce edge thickness and decrease lid sensation its called what? | CN Bevel or hyper flange
🗑
|
||||
| Would you do a CN bevel for a high minus or high plus lens. | High minus
🗑
|
||||
| What is designated to limit lid irritation and keeps the posterior surface away from the cornea? | Lens edge
🗑
|
||||
| The edge of a lens has 3 zones, what are they? | Anterior, posterior, and edge apex.
🗑
|
||||
| What is the addition of plastic to the base of the anterior lens surface? | Prism Ballast
🗑
|
||||
| What is the purpose of prism ballast? | Aids in proper orientation of astigmatic and bifocal lenses
🗑
|
||||
| Removal of the inferior and/or superior portions of the lens to aid in orientation and stabilization is called? | Trunction
🗑
|
||||
| In a _________ lens design, the radius of curvature is the same in all meridians. | Spherical lens design
🗑
|
||||
| What lens design has a spherical posterior surface curvature with a toric anterior curve? | Front surface toric design
🗑
|
||||
| What lens design has a toric posterior curvature with two principle meridians 90 degrees apart and the anterior lens surface is spherical? | Back surface toric design
🗑
|
||||
| What lens design has toric curvatures on both the anterior and posterior surfaces, with principle meridians 90 degrees apart? | Bitoric lens design
🗑
|
||||
| The distance between the posterior surface of the central area of the lens and the flat surface is called what? | Sagittal depth
🗑
|
||||
| What are the movable folds that protect the eye from injury, light, and keep the eye moist by spreading tear film? | Eyelids
🗑
|
||||
| What is the space between the two open eyelids called? | Palpebral fissure
🗑
|
||||
| What is the main support structure of the eyelids? | the tarsal plates
🗑
|
||||
| What does the lacrimal gland do? | produce tears
🗑
|
||||
| Where do the tears drain from the eye? | upper and lower punctums
🗑
|
||||
| What is attached to the punctum that the tears drain into? | the lacrimal sac
🗑
|
||||
| What are the layers of the tear film? | lipid, aqueous, and mucous
🗑
|
||||
| What are 2 functions of the tear film? | forms a smooth refractive surface on the cornea and carries oxygen to the eye
🗑
|
||||
| How would increasing the diameter change the fit of the lens? | tighten the fit
🗑
|
||||
| How would decreasing the diameter change the fit of the lens? | loosen and flatten the lens
🗑
|
||||
| The ability of the contact lens surface to wet can be described by it what? | Wetting angle
🗑
|
||||
| The amount of oxygen that the lens will allow through is measured by its what? | DK Value
🗑
|
||||
| What was the first hydrogel lens polymer used for contacts? | HEMA
🗑
|
||||
| What is the transitional zone from the cornea to the sclera called? | Limbus
🗑
|
||||
| Why would you use a prism ballast on a contacts lens? | to prevent rotation
🗑
|
||||
| what is the reciprocal of the focal length of an optical surface, lens, or system? | Vertex power
🗑
|
||||
| How long does it take a rigid lens wearer to adapt to the way their contacts feel? | 2 weeks
🗑
|
||||
| When doing keratometry, what is the first thing you need to do? | focus the eyepiece
🗑
|
||||
| Is the tear break-up time test included in the pre-fitting evaluation? | Yes
🗑
|
||||
| What instrument is used to evaluate the fit of the contact lens? | Slit-Lamp
🗑
|
||||
| What dye is used to evaluate corneal stains? | Fluorescein
🗑
|
||||
| What type of slit-lamp illumination is it when the beam of light is opened to its widest point? | Diffuse illumination
🗑
|
||||
| When do you use a diffuse illumination? | used for a general survey of the eye and for evaluating corneal staining under the blue light with fluorescein dye.
🗑
|
||||
| what type of slit-lamp illumination is it when the examiner looks directly at the beam of light and adjusts it to 1-3mm wide? | Direct illumination
🗑
|
||||
| When do you use direct illumination? | used for judging the fit of the contact lenses
🗑
|
||||
| What filter is used to verify fluorescein patterns? | cobalt blue filter
🗑
|
||||
| What is the ideal fluorescein staining pattern? | where the center of the lens is faint green and the peripheral is bright green
🗑
|
||||
| what would a steep fluorescein pattern look like? | fluorescein pooling in the center of the lens and faint green in the mid periphery
🗑
|
||||
| What would a flat fluorescein pattern look like? | Very faint green in apex of the lens and pooling in the periphery
🗑
|
||||
| What modification would be needed for a lens that has central pooling? | decrease the diameter for a looser fit or use a flatter base curve
🗑
|
||||
| What modification would be needed for a lens that has peripheral pooling? | increase the diameter for a tighter fit or use a steeper base curve
🗑
|
||||
| What is the biggest advantage soft lenses have over rigid lenses? | Initial comfort
🗑
|
||||
| If a patient has Irregular Astigmatism, what type of contact lens material would you fit them in? | RGP
🗑
|
||||
| What is it called when a patient develops an allergic reaction to deposits on the lenses, resulting in inflammation and bumps on the upper lid? | GPC
🗑
|
||||
| What is the benign yellowish nodule found within the palpebral fissure, just outside the limbus on the conjunctiva called? | Pinguecula
🗑
|
||||
| What are some disadvantages of high water content lenses? | decreased optics and attracts more deposits
🗑
|
||||
| What are some advantages of high water content lenses? | Softer and better initial comfort
🗑
|
||||
| What does the FDA classify material by? | Water content and electronic charge
🗑
|
||||
| What 2 characteristics affect oxygen transmission? | Water content and thickness
🗑
|
||||
| What are some advantages of thicker lenses? | easier handling, durability, and visual stability
🗑
|
||||
| What is a disadvantage of thicker lenses? | Comfort
🗑
|
||||
| What is the main factor in lens comfort? | edge design
🗑
|
||||
| What is the draping effect? | the ability of the lens to conform to the shape of the eye
🗑
|
||||
| In soft lens fitting, the perfect relationship is described as what? | the three point touch
🗑
|
||||
| What is the three point touch? | the lens touches the center and the two opposite edges from the center in any given direction
🗑
|
||||
| The curvature of the lens is dictated by the curvature of the what? | Cornea
🗑
|
||||
| The average corneal curvature is between _____ and _____? | 42.00D and 45.00D
🗑
|
||||
| Is it recommended to start with flat or steep fitting lenses first? | Flat
🗑
|
||||
| For a spherical prescription when do you need to compensate for vertex distance? | +or -4.00D or greater
🗑
|
||||
| If the spectacle prescription is -2.50D, what is the contacts lens prescription going to be? | -2.50D
🗑
|
||||
| If the spectacle prescription is +1.00D, what is the contacts lens prescription going to be? | +1.00D
🗑
|
||||
| When is it necessary to use a toric contact lens? | when the cyl is 1.00 or more
🗑
|
||||
| Starting at 4.00D, for every 2D of power change how much does the vertex factor change? | +0.25D
🗑
|
||||
| From the spectacle Rx -6.00D, what would the contact lens Rx be? | -5.50D
🗑
|
||||
| From the spectacle Rx +8.25D, what would the contact lens Rx be? | +9.00D
🗑
|
||||
| From the spectacle Rx -1.00D, what would the contact lens Rx be? | -1.00D
🗑
|
||||
| From the spectacle Rx -10.00D, what would the contact lens Rx be? | -9.00D
🗑
|
||||
| From the spectacle Rx -3.00-0.50x090, what would the contact lens Rx be? | -3.25D
🗑
|
||||
| Which BC is flatter 8.4 or 8.6? | 8.6
🗑
|
||||
| A certain brand of contacts are available in 8.0, 8.4, and 8.7 BC with a 14.0 diameter. Which base curve should be selected first? | 8.7
🗑
|
||||
| After lens insertion, how long should you let the lenses settle? | 20 minutes
🗑
|
||||
| For any soft lens fit to be considered successful what five criteria must be met? | complete corneal coverage, adequate movement, three point touch, good visual acuity, and patient comfort?
🗑
|
||||
| How far should the contact extend onto the sclera? | 1mm
🗑
|
||||
| How much lens movement is recommended upon blinking? | .5mm to 1mm
🗑
|
||||
| How do you evaluate the lag of a contact lens? | In the slit lamp, instruct the patient to look up, down, left, and right evaluating how much the contact lags behind.
🗑
|
||||
| What parameters must be included when ordering a soft lens? | Base curve, power, diameter, and tint
🗑
|
||||
| What are the 2 most adverse affects to wearing soft lenses? | lens dryness and surface deposits
🗑
|
||||
| When not using fluorescein dye, what instrument is best used to verify the three point touch? | Kerotometer
🗑
|
||||
| What machine is used to verify base curve and optical quality of a lens? | Radiuscope
🗑
|
||||
| What is the flattest curve on a contact lens? | Posterior peripheral curve
🗑
|
||||
| What is the ideal finished edge thickness? | between .08mm and .12mm, measured from .5mm in form the lens edge
🗑
|
||||
| What do you use to verify the lens diameter? | A diameter gauge or measuring magnifier
🗑
|
||||
| A lens surface that gets progressively flatter from center to edge is called what? | Aspheric
🗑
|
||||
| What hydrogel lens material has a polymer made up of repeating hydroxyethyl methacrylate monomer units? | HEMA
🗑
|
||||
| What polymer absorbs and binds water into its molecular structure? | Hydrogel
🗑
|
||||
| What does hydrophilic mean? | Water loving
🗑
|
||||
| What is another name for a lens blank? | a button
🗑
|
||||
| Any curve that is applied outside of the optical zones of the lens posterior or anterior surfaces is called what ? | peripheral curve
🗑
|
||||
| What rigid, non-permeable contact lens material has a polymer made up of polymethyl methacrylate? | PMMA
🗑
|
||||
| What is a small chemical unit, or monomer, linked together to form a repeating chemical chain of high molecular weight? | a polymer
🗑
|
||||
| What is the central anterior curve of a contact lens? | power curve
🗑
|
||||
| What is an oxygen permeable contact lens plastic whose main ingredients are silicone(for permeability) and methyl methacrylate(for durability and stability)? | silicone acrylate
🗑
|
||||
| What is the first thing that should be covered on the dispensing visit? | proper lens care and handling
🗑
|
||||
| How many hours should a new soft lens wearer wear the contacts on the first day? | 4 hours
🗑
|
||||
| How many hours of wearing time should a new soft lens wearer increase each day? | 2 hours
🗑
|
||||
| What are some of the adaptive symptoms in soft lens wear? | tearing upon insertion, mild foreign body sensation, mild photophobia, and sometimes a slight headache.
🗑
|
||||
| What are some abnormal symptoms in soft and rigid lens wear? | persistent pain, burning and excess tearing, redness that does not clear up, hazy vision, and sensitivity to light
🗑
|
||||
| If a patient accidentally sleeps in their contacts what should be the first thing they do upon awakening? | lens lubricant to loosen the lens
🗑
|
||||
| How many hours should a new rigid lens wearer wear the contacts on the first day? | 3 hours
🗑
|
||||
| How many hours of wearing time a should a new rigid lens wearer increase each day? | 1 hour
🗑
|
||||
| What are some adaptive symptoms in rigid lens wear? | tearing upon insertion, lid irritation, excessive blinking, and difficulty looking up
🗑
|
||||
| What does the subjective examination include at the follow up exam? | taking the patient history. what they liked and didn't like about the contacts
🗑
|
||||
| What should the objective examination include? | Visual acuity, overrefraction, slit-lamp examination, and keratometry
🗑
|
||||
| How long should the patient wear the lenses before their follow up check? | 6 hours
🗑
|
||||
| At the follow up check, what should be examined during the slit-lamp evaluation? | lens centration, movement, lens surface, and the lens/corneal relationship
🗑
|
||||
| when doing follow-up K Readings, how much change is acceptable? | 0.50D
🗑
|
||||
| All extended wear contact lenses are designed to be continuously worn for how long? | 1 week
🗑
|
||||
| In extended wear contacts how often should you take them out to clean and disinfect, and how long should you leave the out? | once a week they should be taken out and left out over night
🗑
|
||||
| When should the first follow up visit be with an extended wear patient? | the following morning with in 2 hours of awakening
🗑
|
||||
| what is the typical follow-up schedule of a new extended wear patient? | one day, three days, one week, and 1 month
🗑
|
||||
| What is the subjective symptom of corneal edema? | hazy or foggy vision
🗑
|
||||
| What is another name for a keratometer? | ophthalmometer
🗑
|
||||
| What is rose bengal used for? | A red dye used to stain dead epithelial cells
🗑
|
||||
| What type of corneal stain has pinpoint breaks in the epithelium? | Stippling or punctate staining
🗑
|
||||
| What does a 3 and 9 o'clock stain look like? | stippling on the outside edges of the cornea at 3 and 9 o'clock
🗑
|
||||
| A curved corneal stain in the periphery of the cornea is what type of stain? | Arcuate stain
🗑
|
||||
| What are the points where the top and bottom eyelids meet? | Canthi
🗑
|
||||
| What is the bit of skin that holds sweat and sebaceous glads and is located on the medial canthus? | Caruncle
🗑
|
||||
| What is the average pH of the tear film? | 7.4
🗑
|
||||
| What is Keratitis Sicca? | dry eye syndrome, corneal inflammation due to tear deficiencies
🗑
|
||||
| What is Dacryocystitis? | inflammation of the lacrimal sac
🗑
|
||||
| What is Epiphoria? | faulty drainage causing the tears to spill over the lid margin onto the cheek
🗑
|
||||
| Where is the lipid layer in the tear film produced? | meibomian glands and glands of zeis
🗑
|
||||
| What are the accessory glands that secrete the aqueous layer in the tear film? | glands of wolfring and krause
🗑
|
||||
| Where is the mucin layer in the tear film produced? | goblet cells
🗑
|
||||
| What is the outer tunic made up of? | Sclera and cornea
🗑
|
||||
| Lack of oxygen to the cornea is called what? | Hypoxia
🗑
|
||||
| What does the middle tunic consist of? | iris, ciliary body, and choroid
🗑
|
||||
| What is aniridia? | congenital absence of the iris
🗑
|
||||
| What is it called when someone has unequal pupil sizes? | Anisocoria
🗑
|
||||
| What is rubeosis? | neovascularization of the iris
🗑
|
||||
| What does the inner tunic of the eye consist of? | the retina
🗑
|
||||
| what are the layer of the crystalline lens? | capsule, cortex, and nucleus
🗑
|
||||
| What are the fibers that attach the crystalline lens to the ciliary body? | zonules of zinn
🗑
|
||||
| in contact lenses, where is the base curve measured? | the back surface of the lens
🗑
|
||||
| What curve on the lens in used to create a tear reservoir to help facilitate the flushing effect blinking has on the tears under the contact lens? | the peripheral curves
🗑
|
||||
| The lens diameter should be ______ mm smaller than the horizontal visible iris diameter(HVID) | 2mm
🗑
|
||||
| what is the formula to convert keratometry readings? | 337.5/diopters or 337.5/mm
🗑
|
||||
| What is the fitting curve? | the back surface of the contact lens
🗑
|
||||
| What is the power curve? | the front surface of the contact lens
🗑
|
||||
| When the cornea has more curve on the vertical meridian than the horizontal, it is called what? | with the rule astigmatism
🗑
|
||||
| When the cornea has more curve on the horizontal meridian than the vertical meridian, is called what? | against the rule astigmatism
🗑
|
||||
| A lens that is centered between the top and bottom lids so that the top lid has nothing to do with where the lens is fitted is called what? | intrapalpebral fit
🗑
|
||||
| An increase in peripheral lens edge thickness to aid in raising a low riding contact lens is called what? | myo flange design
🗑
|
||||
| An increase or decrease in the anterior edge thickness to aid in lens positioning is called what? | lenticular flange
🗑
|
||||
| What is the power range of a keratometer? | 36.00D-52.00D
🗑
|
||||
| What is an extra lens added to an instrument for the purpose of supplementary power? | Auxiliary lens
🗑
|
||||
| What illumination is it when the light is right beside the [art of the eye being examined? | indirect illumination
🗑
|
||||
| What illumination is it when the light is behind the part of the eye that is being looked at? | retro illumination
🗑
|
||||
| What slit lamp illumination is it when you shine a 2-3mm light at the limbus at a 90 degree angle? | sclerotic scatter
🗑
|
||||
| Why type of stain is an arc shaped corneal abrasion caused by the edge of a contact lens? | Arcuate Stain
🗑
|
||||
| indentations in the corneal epithelium caused by air bubbles getting between the back of the lens and the front of the cornea is an example of what stain pattern? | dimple veiling
🗑
|
||||
| What RGP lens has no lenticular carrier and is usually spherical? | Single cut lens
🗑
|
||||
| What is residual astigmatism? | The amount of astigmatism left after subtracting the refractive cylinder and the corneal cylinder
🗑
|
||||
| What is a tangent streak RGP? | a traditional executive bifocal design
🗑
|
||||
| What is another name for scleral contact lenses? | Haptic lenses
🗑
|
||||
| What is the profile analyzer? | a tool used to examine the edge design of a RGP
🗑
|
||||
| How do you assess the quality of the peripheral curves? | using a shadowgraph
🗑
|
||||
| The CPC of a rigid lens was ordered 7.84 mm and was received measuring 7.94 mm. This lens is _______ than ordered. | 0.50 flatter
🗑
|
||||
| an excellent material for a keratoconus patient would be? | Silicone acrylate
🗑
|
||||
| What ophthalmic instrument is used to assess the shape of the anterior surface of the cornea? | Keratoscope or placido's disk
🗑
|
||||
| the normal cornea is in a state of what? | deturgesence
🗑
|
||||
| Using a 2-3mm beam, directed at the cornea and a ring of light appears around the cornea to observe opacities, is what type of illumination? | Sclerotic scatter
🗑
|
||||
| Using a 2-3mm beam to see behind the observed area and is used for seeing corneal vascularization, edge design and edema, is what type of illumination? | retro illumination
🗑
|
||||
| What illumination is best to view neovascularization? | Indirect Illumination
🗑
|
||||
| Using a small circular beam of light to view flare and cells in the anterior chamber, is what type of illumination? | Conical beam
🗑
|
||||
| What illumination is accomplished by aligning the microscope along the angle of reflection of the light and is used to detect minute imperfections on the contact lens surface? | Specular reflection
🗑
|
||||
| A form of direct illumination that uses the narrowest beam to see the layers of the cornea and the check angles, is what type of illumination? | optic section
🗑
|
||||
| What is the most common form of direct illumination used to evaluate the fit of contact lenses? | Parallelpiped Illumination
🗑
|
Review the information in the table. When you are ready to quiz yourself you can hide individual columns or the entire table. Then you can click on the empty cells to reveal the answer. Try to recall what will be displayed before clicking the empty cell.
To hide a column, click on the column name.
To hide the entire table, click on the "Hide All" button.
You may also shuffle the rows of the table by clicking on the "Shuffle" button.
Or sort by any of the columns using the down arrow next to any column heading.
If you know all the data on any row, you can temporarily remove it by tapping the trash can to the right of the row.
To hide a column, click on the column name.
To hide the entire table, click on the "Hide All" button.
You may also shuffle the rows of the table by clicking on the "Shuffle" button.
Or sort by any of the columns using the down arrow next to any column heading.
If you know all the data on any row, you can temporarily remove it by tapping the trash can to the right of the row.
Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.
Normal Size Small Size show me how
Normal Size Small Size show me how
Created by:
Kayla Carpenter
Popular Medical sets