NCLE PREP
IF A PATIENT'S K READING SHOWS THE SAME DIOPTER VALUE AT 180 AND 90, WHAT TYPE LENS WILL BE NEEDED ?
SPHERICAL
WHICH IS NOT A SLIT LAMP ILLUMINATION?
►DIRECT ►SCLEROTIC SCATTER ►MODERN ►DIFFUSE
MODERN IS NOT A SILT LAMP ILLUMINATION
WHAT IS ANOXIA?
A DEFICIENCY OF OXYGEN.
NAME THREE TYPES OF BIFOCAL CONTACT LENSES
ANNULAR AKA ASPHERIC
SEGMENTED AKA TRANSLATING
CONCENTRIC
IF A CORNEA IS FLATTER THAN AN AVERAGE CORNEA WHAT CONDITION WILL THIS LIKELY CAUSE?
HYPEROPIA
A CONVEX LENS CREATES A MINUS OR PLUS LENS
A PLUS LENS
A CONCAVE LENSE CREATES A MINUS OR PLUS LENS
A MINUS LENS
WHAT DOES PRK STAND FOR?
PHOTOREFRACTIVE KERATECTOMY
a laser eye surgery used to correct refractive errors, such as nearsightedness (myopia), farsightedness (hyperopia), and astigmatism.
APHAKIC
ABSENCE OF CRYSTALLINE LENS
WHAT IS THE INDEX OF REFRACTION OF THE CORNEA?
1.376
WHAT IS THE AVERAGE DIOPTER POWER OF THE CORNEA?
+43.00 DIOPTERS
WHAT IS THE REFRACTIVE POWER OF A KERATOMETER?
1.3375
WHAT IS THE VERTEX DISTANCE FORMULA?
DIOPTER POWER
1-(MM x DIOPTER POWER)
WHAT IS THE DIOPTER TO MM REFERENCE POINT?
7.50 MM = 45.00 DIOPTERS
FORMULA TO FIND BASE CURVE
337.5 / DIOPTER POWER
FORMULA TO FIND K READING
337.5 / BASE CURVE
FORMULA TO FIND NEW LENS POWER
MM X .3375
WHEN THE POWER OF A CURVE INCREASE BY .50 DIOPTER THE RADIUS OF CURVATURE DECREASE BY?
APPROXIMATELY 0.10 MM
WHAT IS THE ANSI STANDARD TOLERANCE FOR THE DIAMETER OF A CONTACT LENS?
+/- .50
WHAT IS THE ANSI STANDARD OF A POWER OF RIGID LENS WITH THE POWER FROM 5.12 - 10.0 DIOPTERS?
+/- .18
WHAT IS THE ANSI STANDARD OF A POWER OF RIGID LENS WITH THE POWER FROM A LENS LESS THAN +/- 5 DIOPTERS?
+/- .12
HOW MUCH % OF CYL IS PRESENT IF AXIS IS 30 DEGREES AWAY?
25%
HOW MUCH % OF CYL IS PRESENT IF AXIS IS 45 DEGREES AWAY?
50%
HOW MUCH % OF CYL IS PRESENT IF AXIS IS 60 DEGREES AWAY?
75%
HOW MUCH % OF CYL IS PRESENT IF AXIS IS 90 DEGREES AWAY?
100%
WHAT DOES SOAP STAND FOR?
SUBJECTIVE EXAM
OBJECTIVE EXAMINE
ASSESS THE SITUATION
PLAN THE APPROPRIATE MANAGEMENT STEPS
WHAT DOES RSVP STAND FOR?
REDNESS
SENSITIVITY TO LIGHT
VISUAL CHANGES
PAIN
WHAT IS THE TOTAL OPTIC POWER OF THE EYE?
60 DIOPTERS
CORNEA = +43 DIOPTERS
CRYSTLINE LENS = +17 DIOPTERS
IF A LENS JUMPS AFTER A BLINK AND VISION TAKES TIME TO RESETTLE THIS IS AN INDICATION OF WHAT?
LENS IS TOO LOOSE
IF A LENS BARELY BUDGES ACROSS THE BLINK CYCLE THIS IS AN INDICATION OF WHAT?
LENS IS TOO TIGHT
IF A LENS DIPS BRIEFLY AND STABLIZES RIGHT BACK AFTER BLINK THIS IS AN INDICATION OF WHAT?
A NORMAL LENS FIT
WHAT IS THE INDEX OF REFRACTION OF THE VITREOUS?
1.34
SHORTER THE RADIUS CREATES A TIGHTER OR LOOSER FIT?
TIGHTER
A STEEPER CURVE HAS WHAT EFFECT OF THE DIAMETER?
CREATES A LONGER DIAMETER
A TIGHTER FIT IS AN INDICATER OF WHAT KIND OF POWER OF LENS?
A STRONGER POWER
WHY DOES A TIGHTER FIT CREATE A STRONGER POWER?
THE STEEPER CURVE CREATES A PLUS LACRIMAL LENS
THUS A STEEPER THAN K READING
A TIGHTER FIT CREATES WHAT KIND OF RADIUS OF CURVATURE?
SHORTER RADUIS OF CURVATURE
A LOOSER FIT CREATES WHAT KID OF RADIUS OF CURVATURE?
LONGER RADUIS OF CURVATURE
WHY DOES A LOOSER FIT CREATE A WEAKER POWER?
IT CREATES A FLATTER CURVE WITH A MINUS LACRIMAL LENS
A FLATTER THAN K READING
A SHORTER DIAMETER CREATES WHAT KIND OF FIT?
LOOSER FIT
WHAT LENS MODIFICATION CAN BE PREFORMED IN THE OFFICE?
DECREASE THE DIAMETER OF POZ
WHAT IS THE INFLAMMATION OF THE LACRIMAL GLAND?
DACRYODENTIS
WHAT IS THE MOST COMMON LENS DESIGN FOR BOTH GAS PERM AND RIGID LENSES?
CORNEAL LENSES ARE THE MOST COMMON DESIGN
AS SAGGITTAL DEPTH INCREASES VAULTING....
INCREASES
BEFORE 1930 WHAT MATERIAL WAS USED FOR CONTACT LENSES?
GLASS
WHAT DO YOU SEE WHEN THE KERATOMETER IS OUT OF FOCUS?
THE LOWER RIGHT MIRE IS DOUBLED
WHAT INSTRUMENT IS USED TO DETERMINE THE BASE CURVE OF A RIGID CONTACT?
RADIUSCOPE
WHAT IS THE CHORD LENGTH OF THE MIRE MEASURED BY THE KEATOMETER WITHOUT AN AUXILLARY LENS?
3.8 MM TO 2.6 MM
WHAT ARE THE LAYERS OF THE TEAR FILM, OUTSIDE IN?
LIPID, AQUEOUS, MUCIN
WHAT IS THE CURVE ON THE FRONT SURFACE OF THE CONTACT LENS CALLED?
ANTERIOR OPTICAL ZONE RADIUS
WHAT IS THE MOST COMMON REMOVAL METHOD FOR A SOFT CONTACT LENS?
PINCH
WHAT DEVELOPMENT LED TO A DESIGN FOR SOFT TORIC CONTACT LENSES?
DYNAMIC STABILIZATION BY WEICON
WHAT IS A CHRONIC, AUTO-IMMUNE DISORDER CHARACTERIZED BY MONOCULAR CELL INFILTRATION THE LACRIMAL AND SALIVARY GLANDS?
SJOGREN'S SYNDROME
HOW MUCH MOVEMENT DO MOST LENS MANUFACTURERS RECOMMEND FOR SOFT LENSES?
.050 MM TO 1.00 MM
WHO IS CREDITED FOR PRODUCING THE FIRST HYDROGEL LENSES WITH A CHILDRENS TOY BUILDING KIT?
OTTO WICHTERLE
Aniseikonia
A condition in which the image sizes in each eye are different, leading to difficulties in achieving single vision
Anisometropia
Can be recognized where there is a difference of 1.00 D or more between the OD and the OS prescriptions
Blepharitis
Inflammation of the eyelids or eyelid margins
Bullous Keratopathy
A painful eye condition where fluid-filled blisters form on the cornea due to endothelial cell dysfunction
Corneal Edema
Corneal edema is swelling of the cornea caused by fluid buildup, making the eye appear cloudy or hazy
Corneal Striae
Corneal striae are fine vertical lines in the cornea caused by swelling or structural stress, often making the eye look streaked or distorted
Corneal Neovascularization
Forming new blood vessels from existing ones in the iris
Episcleral Injection
Episcleral injection is the visible redness of the eye caused by dilated blood vessels in the episclera
Exophthalmos
Where the eyeball protrudes from the eye socket, making it appear to bulge
Hyphema
The accumulation of blood in the anterior chamber of the eye, usually caused by trauma Ocular Disorders and Conditions
Glaucoma
A group of ocular diseases affecting the optic nerve which can cause progressive vision loss
Giant Papillary Conjunctivitis (GPC)
An inflammatory reaction of the upper eyelid's inner surface, often caused by contact lens irritation
Keratitis Sicca
An inflammation or irritation of the cornea caused by dry eye
Keratoconus
A progressive eye disorder that affects the cornea, causing it to gradually thin and take on a conical shape, bulging forward
Macular Degeneration
Deterioration of the macula that causes central vision loss
Nystagmus
An involuntary oscillation of the eyes that can be caused by a variety of conditions
Pinguecula
A yellowish, raised growth on the white part of the eye near the cornea
Pterygium
A growth of tissue on the conjunctiva that typically starts on the sclera and grows toward the cornea
Retinal Detachment
Retinal detachment is a serious condition where the retina separates from the back of the eye
Retinitis Pigmentosa
A group of hereditary diseases that cause progressive degeneration of the retina and may cause total blindness
Uveitis
Describes any inflammation of the uvea, including the iris, ciliary body, or choroid
The lens edge can be divided into three zones:
Anterior Zone
The edge in contact with the upper lid during the blink cycle. Its function is to minimize lid irritation during blinking.
Posterior Zone
A small reverse curve on the posterior surface designed to flare the edge away from the cornea.
Edge Apex
The junction between the anterior and posterior zones. This area must be well-rounded to reduce lid awareness during the blink cycle.
WHAT TYPE OF LENS WILL SHOW TWO SEPARATE RADUSCOPE MEASUREMENTS FOR EACH LENS SURFACE?
A BITORIC LENS
Ametropia
Any condition where light cannot focus on the retina, myopia, hyperopia, and astigmatism.
Amblyopa
Also known as 'lazy eye.'
Antimetropia
one eye is hyperopic and the other is myopic
Aniscoria
unequal pupil size
Increasing the diameter of a contact lens with result in a
looser fit or tighter fit
tighter fit
A Fleischer ring is an early sign of what condition?
Keratoconus
Arcus Sinilis
a white or grey ring of lipid, (fat), deposits forms around the outer edge of the cornea - often part of aging
DK/t
refers to the amount of oxygen that passes through a lens material of specific thickness
Trichiasis
Eyelashses grow inward
Ptosis
Dropping eyelid
Ectropion
Eyelid turns outward
Entropion
Eyelid turns inward
How many transitional zones will a quadcurve lens have?
Three
Optical Zone, Transitional Curves (2), Landing Curve
What is the most common design for both gas perm and rigid lenses?
Corneal Design
What test is used to measure corneal thickness?
Pachymetry
Strabismus
A misalignment of the eyes
Esotropia - Inward turning
Exotropia - Outward turning
What is an Emmetrope?
A person who needs no refractive correction.
What type of astigmatism may be revealed by viewing a spherical rigid contact lens on the cornea?
Corneal Astigmatism
The curvature on the anterior surface of a contact lens is called?
Anterior Optical Zone Radius
What lens diameter might be selected to achieve a corneal alignment (lid attachement) fit with an RGP lens?
9.5 mm is the lens diameter for a corneal alignment fit with an RGP lens
What does HVID mean?
Horizontal Visible Iris Diameter
What is the primary function of the digital corneal topographer?
Measure the curvature of the cornea
What astigmatism do these K-Readings represent?
43.00 @180/44.00@90
WITH THE RULE
What astigmatism do these K-Readings represent?
43.00@180/43.00@90
NO ASTIGMATISM
What astigmatism do these K-Readings represent?
44.00@180/43.00@90
AGAINST THE RULE
What astigmatism do these K-Readings represent?
43.00@135/44.00@45
OBLIQUE
What is the most common removal method of a gas perm lens?
Blink Method
What is the most common removal method of a soft contact lens?
Pinch Method
WHAT KIND OF AN ASTIGMATISM DOES THIS RX REPRESENT?
RX: +1.00 -1.00 x 90
Simple Hyperopic Astigmatism
One image is formed behind the retina and the other on the retina.
True Powers: +1.00 x90 and pl x180
WHAT KIND OF AN ASTIGMATISM DOES THIS RX REPRESENT?
RX: -1.00 +1.00 x 90
Simple Myopic Astigmatism
One image is formed in front of the retina and the other on the retina.
True Powers: -1.00 x90 and pl x180
Vertex Distance Rule of Thumb
10-10-1
What accurately measures the surface curves of the anterior and posterior surface of rigid contact lenses?
Radiuscope
What is the Index of refraction for the tear film?
1.336
A specialty contact lens which is comprised of a soft carrier and rigid center is called a
Hybrid Contact Design
EXO -
OUT
IE. EXOPHORIA - TENDANCY OF THE EYE TO TURN OUTWARD
IE. EXOTROPIA - DEFINATE TURNING OF THE EYE OUTWARD
ESO -
IN
IE. ESOPHORIA - TENDANCY OF THE EYE TO TURN INWARD
IE. ESOTROPIA - DEFINATE TURNING OF THE INWARD
HYPER -
UP
IE. HYPERPHORIA - TENDANCY OF THE EYE TO TURN UPWARD
IE. HYPERTROPIA - DEFINATE TURNING OF THE UPWARD
HYPO -
DOWN
IE. HYPOPHORIA - TENDANCY OF THE EYE TO TURN DOWNWARD
IE. HYPOTROPIA - DEFINATE TURNING OF THE DOWNWARD
WHICH TEST IS USED TO MEASURE CORNEAL THICKNESS?
PACHYMETRY
WHAT IS THE INDEX OF REFRACTION OF GLASS IF LIGHT TRAVELS THE SPEED 133,000mi/sec
1.398
CORNEAL LENSES AKA SOFT CONTACT LENSES
►9-15 MM
►RESTS ON CORNEA
►INTIALALLY DISCOMFORTING DUE TO RESTING ON CORNEA
►LESS STABLE, CAN MOVE OR DECENTER ON EYE
►IDEAL FOR MINOR CORNEAL IRREGULARRITIES, HIGH ASTIG, HIGH MYOPIA, ORTHOKERATOLOGY
SEMI - SCLERAL LENSES AKA RIGID/GAS PERMAMABLE LENSES
►13-15 MM
►RESTS NEAR THE LIMBUS, (WHERE THE CORNEA AND SCLERA MEET)
►MINIMAL OR PARTIAL VAULTING OVER THE CORNEA
►GENERALLY MORE COMFORTABLE AND STABLE THAN CORNEAL LENSES
►IDEAL FOR MILD TO MODERATE CORNEAL IRREGULARITIES OR PTS WHO CANNOT TOLERATE CORNEAL LENSES
SCLERAL LENSES AKA HAPTIC LENSES OR PMMA LENSES
► 15-24 MM
►VAULTS COMPLETELY OVER THE CORNEA AND LIMBUS, RESTING ENTIRELY ON THE SCLERA, (THE WHITE OF THE EYE)
►LACRIMAL LENS IS CREATED BETWEEN LENS AND COREAN
►HIGHLY COMFORTABLE AS IT RESTS ON THE LESS SENSITIVE SCLERA
►EXCELLENT STABILITY DUE TO LARGE SIZE
►CAUSES SEVERE DRY EYE, IDEAL FOR KERATOCONUS, POST-CORNEAL TRANSPLANTS, AND POST-LASIK COMPLICATIONS PTS
What is another term for
Central Posterior Curve
Primary Curve
Focusing on a NEAR object the ciliary muscles
► contract ►relax
Contract
the ciliary muscles CONTRACT moving twoards the lens and releases the tension on the zonular fibers allowing the lens to spring back and THICKEN into a more CONVEX shape which INCREASES THE refractive power to focus on the nearby image
Focusing on a DISTANT object the ciliary muscles
► contract ►relax
Relax
the ciliary muscles RELAX and expand outwards pulling the zonular fibers tight and pulling on the lens stretching into a THINNER, FLATTER shape which has refractive power allowing the eye to focus on faraway objects.
What is the name for a group of corneal conditions that cause thinning and buldging?
► Catract ► Ptergium ►Ectasia ►Blepharitis
Ectasia