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191 Cards in this Set
- Front
- Back
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1. Central Circular Clouding or PMMA edema OR Sattler’s veil:
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a. EPITHELIAL clouding, seen with HARD lenses. Gray haze in center
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2. Vertical striae aka Hydrogel edema:
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a. Vertical, isolate, wispy lines in posterior stroma when edema is > 6-7%. Seen with extended wear SOFT CONTACT LENS. NO light scattering effect, NO change in VA.
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3. Fuch's dystrophy
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Stroma folds on itself. Occurs when ENDOTHELIAL cells gradually deteriorate. As more endothelial cells are lost, LESS efficient PUMPING of water occurs out of stroma.
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Microcyst edema
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Epithelial and ANTERIOR stroma cysts. Asymptomatic. Due to extended usage of SOFT CONTACT LENSES. Show a REVERSED ILLUMINATION. HALLMARK SIGN. Due to greater index of refraction of microcyst than the cornea.
NON reversed illumination: water micro blebs. Due to refracive index of water being less ten that of the surrounding cornea. |
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Superficial Punctate Keratitis
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breakdown in surface epithelium
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Fick
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First sucessful contact lense fit
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Mullen
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"corneal lenses"
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Obrig and Mullen
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PMMA molds!!
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Tuohy
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plastic lens, first modern lens
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Wichterie, Lim, and Dreifus
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Hydrogels, soft contacts
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Bausch and Lomb
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First HEMA
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Ocular side effects w/ meds: RAD MOM
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Refractive change
Altered behavior Dry eye Mydriasis Ocular Irritation Miosis |
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Hard Contacts arePMMA
Soft contacts --> Hydrogels Rigid Contact lens --> RPG |
< 1% wear
85% wear 15% wear |
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Normal corneal HVIC vs VVID
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12 mm
13mm |
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Lid position
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+1 if over limbus
0 if at limbus -1 is lid is below limbus |
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Edema od cornea leads to vertical striae at what percent?
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>7% swelling.
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Keratometry problems
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only measure 4 points in central 3mm (2 flat, 2 steep meridians)
Keratometer also assums cornea is spherical. |
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Rigid lenses
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Great optical quality, smaller, mroe oxygen porous!, great for myopia and can be used for othokeratology.
Disadvantage: COMFORT and longer adaptation time. USE proparicaine |
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Partialblink/flick blink
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Occurs with RPGs. Once lid ishalf way down it touches the lens, becomes irritated, and goes back up ---> LEADS TO DRY EYE and other complications
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Major role of endothelium
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PUMP to keep fluid out
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Types of Edema
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CCC
Vertical Striaee Fuch's Epithelial Microysts Superficial Punctate Keratitis |
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CCC
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Central Corneal Clouding ---> PMMA EDEMA!!!
also known as Sattler's veil. HARD KENSES, See gray haze, decrease in VA, also get staining! |
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Vertical Striae
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HYDROGEL EDEMA!!!
vertical, isolated wispy lines in POSTERIOR stroma, visible > 6-7% edema. NO decrease in VA More edema, more striae |
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Fuch's Dystrophy
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Stroma FOLDS onto itself, endothelial cells DETERIORATE, less efficient at pumping out water --> distorts vision
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Epithelial Microysts
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Epithelial cysts in ANTERIOR stroma. SEEN IN REVERSED illumination! index of refraction of cyst is greater than cornea.
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Superficial Punctate Keratitis
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BREAKDOWN OF SURFACE epithelium
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Limus --> shows signs of hypoxia
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Limbal enjorgement/hyperemia, is the precursor to neovascularization. Causes Dilated vessels and MAST cells to be present
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Vessel penetation should not exceed how many mm?
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1.5!!!! Or else we have neovascularization
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Micropannus
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Inflammatory movmenet of blood vseels into corneal tissue --> response to STAPH!
see fan shaped clouding of cornea located at 6 o'clock |
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Kruase and Wilfring
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Supply large volumes of tears
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Folliculousis
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follicles from viruses: are round, clear, with superficial blood vseels
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Papillae
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bumpbs on lid CAUSED BY CL! and allergies.
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GPC
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small to giant papillae of tarsal conj. More frequent in hydrogels
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Pinguecula
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Pink, fatty tissue, harmless
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Pterygium
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wing shaped, elevated growth on cornea, contraindication to fit CL, needs surgical remmoval
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Micropapilla
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Bumpbs on conj, mast cells --> CASES RED EYE
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Chemosis
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NOT due to CL, but is an allergic reaction
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MGD Meibomiam gland dysfunction
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Patient will ave dry eye because glands are plugged. Not enough oil in outer layer of tear film --> get excessive evaporation an dry eye.
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Ectropion
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excessive teaing when puncta is not in place to drain tears
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CL is in contact with......
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TEAR FILM
90% tear film 10% microvilli interdigitates |
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Tear film composed of
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Mucin layer, Aqeuous layet, Lipid layer
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To maintain Tear film neuronally
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Need CN 7 for tear secretion
CN 7 for blink (tear clearance) |
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Closed eye are more _______ than open eyes
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Hypotonic --> leads to swelling
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TBUT measures
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DEYDRATION OF TEARS!!! not how much is produced but how long it takes to remove.
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Schirmer test
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measures PRODUCTION of tears
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Biota of the eye
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Usually gram +
Gram - is fron environmental contaminations |
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CLPU
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CL Periperal Ulcer --> gram + bacteria --> S aureus.
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CLARE
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CL ACUTE RED EYE --> Gram -. Endotoxins
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Most common cause of corneal infections
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P. aeruginosa
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Hydrocurve lenses
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HEMA + NVP. Improves wettability. More water= more oxygen, BUT also needs to be thicker because its weaker material
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Group 1 Low Water Non-ionic
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Less water means less O2 permeability, but it also attracts less debris
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Group 2 High water Non-ionic
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More O2 permeability, decrease debris attraction. MAY BE THICKER
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Group 3: Low water ionic
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Less O2 permeabiliy, attracts debris. GOOD FOR DISPOSABLES
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Group 4: High Water, ionic
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Increase in O2 permeability, attracts debri. Godo for hyperopes or high myopes. Good for replacement lens!!
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Silicon hydrogels
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LOW water contennt ut high transmissity of O2.
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The higher the water content....
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the thicker the lens.... decrease transmission.
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Old lens were ___ thick
New lenses are _____ thick |
.35
.035 |
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Anterior optic zone is no smaller than
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8 mm, or it would induse flare
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Bread and butter rule
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Keep C same and increase diameter, sag increases and lens TIGHTENS
If you increase steepness (decrease BC ) and keep diameter the same, sag increases and lens TIGHTENS |
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To loosen a lens
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decrease Diameter or flatten BC (increase it)
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Changing the shape of the back curve of the lens using spin cast
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does not make much of a difference for the performance of the lens of the eye
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Normal TBUT
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above 10 sec
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Abnormal neovascularization
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1.5 mm or more
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Must use effectivity when
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power is + or - 4 D
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When deciding to go with toric or spheric lenses, you can try spheric if the ratio of sphere to cyl is:
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4:1
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Soft contact lens
Calculated Residual Astigmatism= |
Total Refractive Astigmatism
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Rigid Contact Lens
Calculated Residual Astigmatism= |
Total Refractive Astigmastism-Keratometry readings
Since its - a minus, you add them |
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So if the astigmatism is at the cornea=
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RPGs are better at solving the problem, because soft contact lenses will just drape over the cornea and not change the shape.
However if the astigmastism doesnt lie on the cornea itself, and the residual astigmastism is internal, you can use a soft contact lens |
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5 criteria for soft lens eval
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MVP CH
Movement Viscual Acuity Position Comfort Health |
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Edge standoff
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feels like an eyelash to the eye. The edge of the lens flips. Fit the lens to be larger, steepers, and or/ tighter.
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Flexing phenomenon
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when patient blinks, the cl is pushed up against the cornea and vision is improved. Occurs when a lens is not setttled properly. May need to give patient something flatter
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If lens is too loose
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We will see excess movement
Superior or temperal superior |
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if lens is too loose
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We will see no movement, inferior position, some flexing
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See mires fuzzy, clear, fuzzy
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TIGHT fit
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See mires clear, fuzzy, clear
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LOOSE fit
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Eosinophils
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allergic
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Nuetrophils
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bacterial
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Lymphocytes
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viral
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Jelly bumpbs
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Cholesterol on lens due to deposits from tears in patient with high cholesterol. Effect VA, seen in torics because they dont rotate
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Centrak ounctyate staingin
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usually due to tight lenses, especially in HYPEROPES which have thick centers.
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Foreign Body Tracks
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Can be a one time thing, see geometric linear appearance
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SPK Superficial Punctate Keratitis
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Usually due to an allergic reaction, dry lenses, or tight lenses.
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Prowl line
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Shows up in people that do not blink well, see lid deposists that collect on bottom of lens
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Arcuate stain
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due to bad edge or blend of CL
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Inferior nasal stain
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Due to bad placement of CL, does not sit well inferiorly, get nasal exposure. Lens can be too small
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Superfical stippling
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dirt behind lens
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Superior Limbic Keratitis
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Superior cornea and conj injection, stainging and filtrates.
Seen in middle age women bilaterally. |
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Contact lens keratoconjunctivivis
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Supepithelial infilatres, painl, light sensitivity, edema
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Edema is graded from
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0-3, 3 being the most severe
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% of O2 in air
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21%
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Closed eye has __________ reduced oxygen supply
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2/3
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21% of 760 mm Hg=
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155 mg Partial Pressure of Oxygen in on CL patient
In aspin, the oxygen is 15%!! --> 137 mg |
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RGOs get 1-3% oxygen from
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tear pumping mechansim.
SCL ONLY gets oxygen thru transmition |
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cornea needs ____ oxygen tofunction properly
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2-5%
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Equivapent Oxygen Percentage EOP
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equals the concentration of O2 in gaseous mixture that induces an equvalent oxygen thrist of the cornea. An open eye needs 10% or more oxygen to prevent edema
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Normal eye consumption rate is ___
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21%
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Critical oxygen for cornea is 2-5% but clincally we want _____ for safe function
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8-10%
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EOP Equivalent Oxygen Percentage is a _______ measurement
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biological
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PMMA Equivalent Oxygen Percentage is
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0, DOES NOT LET Oxygen in
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Permeability is measured in
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DK is in barrer
Dk is Diffusion coefficient times solubility coefficient |
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Dk is
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independent of material thickness
DEPENDANT on temperature. DOES NOT tell you how much oxygen is transmitted, just how well O2 permeates into the lens. Dk for soft contact lens = water content of lens |
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Dk/t is Oxygen TRANSMISSIBILITY
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It is a LENS PROPERTY and a PHYSICAL test. (EOP was biological)
Measured in barrer/cm Lens does not have to be worn to determine value Typically measured at -3 D and 35 degrees C. |
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Boundary Layer Effect
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Reduces effective Dk/t of a lens on eye. O2 molecule arrives at front surface of lens faster than it can penetrate into lens, it thus gets trapped in the interface surfaces
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Must measure Dk/t average of entire lens because
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lenses are thicker and thinner at different areas depending on type of prescription and power of prescription
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RGP Permeability
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Gas dissolves thru anterior lens, thru lens proper, thru posterior lens, disolves into poster lens tear film and then fluirinated material
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EOP can never exceed
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21%
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O2 supply via blinking for RGP
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15-20% per blink, GREAT tear exchange.
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Hyopoxia in epithelium leads to
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Decrease in Oxygne flux
weakened hemidesmosomes Decreases mitosis --> SPK punctate staining Epithelial thinning Hypoethesia Microcysts |
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Hypoxia in stroma leads to
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Edema, thickening
striae and folds (striae at 7% and folds at 10%) Stroma thinning after long term hypoxia Vascualrization Shape/change exhaust 15-20% edema is pathological and leads to endothelial cell damage |
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Normal swelling of eye with no lens
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on average its 4%, deswelling occurs within 90 minutes after eyes are open
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Soft lens overnight swelling
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4% of normal + 8% due to lens = 12% overnigt
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Polymegethism
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increase in variability of size and shape of enodthelial cells. IRREVERSIBLE
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Mertz Holden Criterion:
SCL Daily Wear |
Swelling= 0%
Minimum O2 % dk/t=24.1 EOP 9.9% |
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MErtz Holden Criterion:
SCL Extended wear |
Swelling= 4%
Minimum O2 % dk/t= 87% EOP= 17.9% |
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D Value Test
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Lower is better --> time it takes to reduce pop of organizsm to 90%
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Disinfection
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Reduces level of microbio. to safe level --> SPORES survive
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Sanitize
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Make clean
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Sterilize
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KILL microbes + SPORES. 121 degree C for 15 min at 15 psi for autoclave
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Asepticize
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free from disease producing acteria
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Pellicle
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Micoprotein surface coating. Bacteria adheres and uses it as food.
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Emulsify
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Good for lipids
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Preservatives include:
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Dymed,polyquad, sorbic acid, thimersoal
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Dymed
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Low tox, some absor into matrix
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Polyquad
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No abs into lens
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Sorbic Acid
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bacteriostatic, breaks down can can cause LENS DISCOLORATION if used with H2O2.
FOUND IN B& L SENSITIVE EYES |
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Thmerosal
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Combo with EDTA and clorhexidine. Aders to protein deposits. Not used now.
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Miraflow
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practioners use ONLY. EXTRA strength cleaner
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Heat disinfection
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fast, cheap, destructive and OBSELETE.
Good for acanthamoeba, effective against FUNGI |
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Cold disinfection
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fast, expinsive, 4 hours to soak
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H2O2 disenfection
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expensive, bacteriocidal, good for killing HIV, BAD for fungi
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Dymded
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found in B & L RENU.
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Polyquad
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Found in Alcon Optic Fre
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Thimerosal
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antifingunal and microbial. No longer used
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Chlorhexidine
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biguanide agent. Disrupts lipid layer of cell membranes. Binds to hema. Selcom used
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Sorbic Acid
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bacteriostatic, breaks down can can cause LENS DISCOLORATION if used with H2O2.
FOUND IN B& L SENSITIVE EYES |
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Thmerosal
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Combo with EDTA and clorhexidine. Aders to protein deposits. Not used now.
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Miraflow
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practioners use ONLY. EXTRA strength cleaner
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Heat disinfection
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fast, cheap, destructive and OBSELETE.
Good for acanthamoeba, effective against FUNGI |
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Cold disinfection
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fast, expinsive, 4 hours to soak
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H2O2 disenfection
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expensive, bacteriocidal, good for killing HIV, BAD for fungi
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Dymded
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found in B & L RENU.
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Polyquad
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Found in Alcon Optic Fre
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Thimerosal
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antifingunal and microbial. No longer used
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Chlorhexidine
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biguanide agent. Disrupts lipid layer of cell membranes. Binds to hema. Selcom used
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Benzalkonium chloride
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Gram - and + organizms. ONLY for hard lenses
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RENU MULTI-PURPOSE
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CONTAINS HYDRONATE--> NONenzyme protein remove
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HYDRONATE
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--> NONenzyme protein remove
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Optic Free Replensih
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contains ALDOX kills acanthamoeba
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AOSEPT
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one step system, neutraizes peroxide into saline
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ULTRACARE
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Pink colored catalse to clean and neutralzie peroxide
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Purilen
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UV light to clean
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Subtilisin A
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Controlled fermentation of Bacillius Lichenformis
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Papain
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original enzyme, can be ocular discomfort
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Pancreatin
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enzyme. Optic free- better against lipids and mucoids
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Causes of lens discoloration:
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Sobric acid, postassium sorbate, thimerosal (blackens), hydropen peroxide (pink), benzyle peroxide (acne med_
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Lysozyme
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bactericidal against G+
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Lactoferrin
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bacteriostatic, good against G-loppoly
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sIgA
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Engulgs by PMN. DECREASES with CONTACT LENS USE --> MORE PRONE TO INFECTION!!!!!!
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Complement
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30 antimicrobial proeints, leak into tears while sleeping --> lysisis membranes of microbes.
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Contact lens wear does NOT affect ______________________
but does effect _______ levels |
LYSOZME AND LACTOFERRIN
IgA |
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EW Dk/t need:
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125
Hydrogels: <35 RGP: +100 |
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Ciba Night and Day
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DK/t 175
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No myopic creep occurs with
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silicone hydrogels
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Grade Neovasc 1
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< .5 mm or 1 or 2 vessles extending less than 1.5 mm from cornea
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Neovasc 2
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.5-1.5mm into cornea
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Neovasc 3
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1.5-2.5 mm into cornea
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Neovasc 4
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> 2.5 mm into cornea or vessel withi 3 mm of corneal apex into visual axis.
NOT DUE TO CL but from disease |
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epithelial microcysts
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Basal layer!! cyst odies. Seen in hyrogel EW. Hypoxia alters epithelial cellular metabolism. Migrate to surface and release debri that stains! REVERSED ILLUMINATION.
IS NOT CAUSED BY SILICONE HYDROPGELS. INCREASE water content and decrease thickness. |
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Tight lenses lead 2 two conditions
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CLARE Contact lens acute red eye
SEAL Superior epithelial arcuate lesion |
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SEAL
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Superior epithelial arcutate lesion:
MECHANICAL complication with soft CL. edge rubs onto cornea. See arcuate epithelial lesion, ac like grayis white epithelial lesion, heaped edges, inflitration, staining. MAY BE MORE PREVELENT in SILICONE HYDROGEL due to higher higher rigidity give antibiotic to treat |
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CLARE
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Contact Lens Acute Red Eye
Usually unilateral Bulbar injection pain lacrimation photophobia no staining TIGHT fitting soft lens with tapped debri --> tight lens syndrome possible guttata Starts at NIGHT infiltration in peripery and mid periphery give Fluroquinolone to protectagaint GM- Reduced rates with silicone CL |
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CLPU
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Contact Lens Peripheral Ulcer-
anterior stromal infiltrate with full thickness epithelial defect WHITE SPOT ON EYE mild irritation ocular redness localized limbal/bulbar injection small scar, fade after 6 months WILL NOT CULTURE: noninfectious decreased rates with silicone |
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Phlyctenulosis
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delayed sensitivity to staph toxin
seen with chlamidyia and TB ELEVATED WHITE LESION contains eosinophils. Treat with Tobradex |
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CLPC
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Contact Lens induced Paillary conjunctivitis:
GPC Ropy muscuous disscarge itchness,blurry vision, scarring, tarsal redness, papillae, conj edema and ptosis. Mast cells, eosinophils, IgE. Grade 1: mild itchiny, no papil Grade 2: mild lens awareness, mucus, tarsal hypermia Grade 3: larger papillale >1 mm with infiltrates 4: Severe mucus, large pailallie, staining and infilatres, lid edema. TREAT grade 3 and 4 with Patanol and steroid (Lotexma) |
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Microbial Keratitis
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Loss of epithelial and stromal tissue due to invading bacteria. Chronic hyopxia LEADS TO IT!!!!!
5 fold increase with extended wear cl. Decrease risk with silicone. DUE TO P AEURGINOSA!! Gram -. Sometimes also due to Gram + Staph and Strep P auerg: Gram -, also responsible for inflammation with CLARE due to ENDOTOXIN!! See Hypophon --> cells in clare in anterior chamber. have pain, redness, photobia, mucpurlent discharge, blurry vision, lid swelling, large lesions, cells in falre, eyelid edema. GIVE FLUORQUIN. 1 ggt 5 x 30 min/2 gt q 15 min x 6 hr, 2 gtt q 30 min x 18 hrs, 2 ggts h thereafter for 14 days. |
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Acanthomeiab keratitis
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Rare funal painful an potentially blinding infection
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Non infection ulcer versus infectious ulcer:
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Sterile has:
smaller lesions, more peripheral less epithelial damage, NO discharge, less pain and photophiba NO AC reaction NO lid involvement |
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Infiltrative Kertisis
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acute inflammation with prescence of intraepithelial or subepithelial infiltrates.
Caused by bacterial toxins from Gram -. STARTS DURING THE DAY. Mild irriation, redness, tearin, NO discarge. See periperal intra/suepitheial infiltrates, rarely see scars, no AC reactions. Use steriods |
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Empirical Method for torics
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Patients Rx is orderedWhy do toric Hyodrgels mislocate?
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NATURAL vector fores of the lids.
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The lids squeeze thin parts of lens. Since prism is usually at 6, the upper lid pushes on the thinner top.
Vector foces lens to move towards nose --> spins lens. Thicker portions of lens moves towards nose. |
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Thickness of Axis toric lens
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Oblique axis is HARDEST to stabalize!!
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Truncated Lens with Prism
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NOT used anymore. Increased thickness and sharpe edyes of lens. Made it even more uncomfortable, saw central corneal thickness withing one hour of wear
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Prism Ballast
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Used toda. Decreses but does not eliminate rotation. Adds BD prism to lens. GRAVITY does not play a role, but rather the WATERMELON principle does.
Apex on top of lens moves lens down and pushes it against globe. |
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Watermelon Seed Principle
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Controls movement of CL!!
GRAVITY does nothing. Upper lid squeezes on thin lens and pushes it down onto lower lid. |
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Prism Ballast examples:
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B& L Optima --> Front toric lens.
3 Laser marks 30 degrees away. CSI Toric--> solar. BACK toric. 3 laser marks. Center laser mark is larger. |
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Thin Zone Design --> Dynamic Stabilization
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Ciba Vision Torisoft.
Double-slab off design and lower edges are equally thin. NO INDUCED PRISMATIC EFFECT NO PRISM Works great for ATR and HIGHER myopes. Double slab off |
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Periballast
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No prism!!!! But Ballested. Great for high cyl and obliques.
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Eccentric lenituclarization
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Lens optics are not exactly centered.
Back toric! UNIFORM edge thickness--. CYL DOES NOT EFFECT ROTATION. cyl is all found in center of lens. Change in RX does not affect lens orientation. |
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Combo toric lens examples
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Durasoft Optifit Toric -->
20 degrees between lenses Ocular Science Biomedics 55 Toric --> FAVORITE. 2 week disposable toric. Isoballasting --> uniformly thin 360 degrees around. |
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Lathe Cutting/Crimping
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Original method of creating toric. Dry procedure. not very good and pretty expensive
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Stock Lenses
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Standard lens rady to be shipped. cyl power= .75-2.50 D
sph: 0-6 D axes: with 10 degrees |
