Complete List of Terms and Definitions for Contact Lenses III MT 2 - Keratoconus

Terms Definitions
T/F - Prism-ballasted front-surface torics can work with K-cones. False ("Nah!")
What is the most common unilat sign of K-conus? Vogt's Striae (bottom left pg 3)
What RGP fitting philosophy is best for achieving a "successful" fit with K-cones? Fit flat - touch cone apex
K-conus progressive until... 3rd to 4th decade
T/F - It is possible to judge the amount of bearing (e.g. "1.00D flat") based on the FP in K-cone RGP fits. False - can't tell if too flat since the amount of bearing can be very similar between two lenses of different BCs (due to shape of cone apex)
Why do a blend in K-cone RGP fits? Makes periph curve system more "aspheric"
Center thickness in K-cone RGP fits are typically (thinner/same/thicker) vs. normal RGPs. Why? slightly thicker, even though high minus CLP, because of relatively flat periph curve system.
Name the steps in the Game-Day Game-Plan for K-cones. 1) Measure K curvature2) Select first trial lens BC3) Eval apical FP4) Observe pooling under OZ5) Eval edge lift/PC6) Sphero-cyl OR
Your first trial lens BC in fitting K-cone RGPs should be... somewhere between steep K finding and avg K value (fudge toward steep K)
CLEK survey = __% diagnoses between ages __ and __ years. 90%, 10, 39
K-conus = symmetrical or asym? Asymmetrical
When is a large OAD for K-cones indicated? - Decentered cone apex- Enhance initial comfort
What is the NKCF? National Keratoconus Foundation
CLEK survey: __% of sample less than 50 years of age. 98.7%
CLEK study sample showed __% reported a family Hx of K-conus at baseline (parent, sibling, child, aunt, or uncle) 13.5%
T/F - There is usually no relation between your subjective refraction and CLP in K-cone RGPs. True - but typically CLP is more minus
What Dk is typical for K-cone RGPs? DK ≥60
Why is a bitoric design "tempting" to use with K-cones? Irregular astigmatism thus no particular corneal toricity. Even if periph cornea is toric, bitoric design is more apt to peripheral seal-off.
What three main signs are involved with K-conus? - Fleischer's Ring: iron deposits at base of cone- Vogt's Striae: "stretch marks", different from striae in edema b/c mostly (not always) vertical and see few.- Scars: cause unk (possibly eye rubbing or cone itself?)
Which RGP fitting philosophy is best for longer wear time in K-cones? Fit flat - more peripheral clearance allows better tear exchange vs fitting steep
Average age of Dx K-conus = __ years old, based on CLEK. 27.3
K-cone RGP power is usually (plus/minus)? minus
K-conus more prevalent in males or females? Relatively equal incidence (CLEK sample = 56.4% male, 43.6% female)
In Rose K, the BC is (sphere/aspheric), and the PC is (sphere/aspheric) sphere, aspheric
You see minimal periph clearance when fitting your K-conus pt with your DxCL; what parameter should be changed in your order and how? Order flatter SCr
You should do a sphero-cyl OR on a K-cone with which of the following trial lenses:1) Steepest touch2) Flattest clearance3) Steepest clearance4) Flattest touch 1) Steepest touch
T/F - CLs can stop the progression of K-conus. False
Which RGP fitting philosophy is best for less disruption to the cone apex in K-cones? Fit steep - less rubbing on apex therefore less scarring
What is the problem with K-cone SCLs? Tend to be thick therefore poor O2 transmissibility.
T/F - CLEK was an experimental study funded by the NEI involving an 8-year follow-up. False - observational study
What is a good strategy to minimize the area of tear pooling around the base of the cone? Decrease the OZ (see figure middle right pg 8)
What is the OAD of KBA? 10.2 mm
What does FDACL stand for in K-cone RGP fitting? What is the significance? First Definite Apical Clearance Lens - want to find the flattest lens that will result in AC (then eventually fit the steepest AT lens).
When is a piggy-back lens indicated for K-cones? For initial comfort, 3-9 staining, or bandage
T/F - Ortho-K is contraindicated for K-cones. True
T/F - LASIK is ok for K-cones. False - cannot do LASIK in K-cones due to thin cornea
K-conus age of onset? Puberty
CLEK study: Hay fever or allergies = __% 53
CLEK study: Atopic dermatitis = __% 8
Earlier onset of K-conus = (more/less) severe? more
Rose K2 typically has (smaller/larger) OZs. What is the significance of this? larger; improved night vision, decr image ghosting and aberrations
What behavior is commonly assoc w/ K-conus? What is the prevalence of this behavior in K-cones? Eye rubbing49% both eyes1.8% rub only one eye vigorously3.2% unsure whether they rubbed their eyes
CLEK survey: mean age of diagnosis = ___. 27.3 ± 9.5 yrs
K-conus = inflam or non-inflam? non-inflammatory
K-cone RGP OZ is usually (smaler/larger) vs typical RGPs? smaller
There tends to be a (+/-) TL in K-cone RGP fits? +
What are the three main goals for K-cone RGP fits? 1) Feather "three point" touch2) Minimize tear pooling3) Maximize periph clearance
T/F - In K-cone RGP fits, an increase in BC (in D) typically means a decreased OZ. True
What benefits and problems are assoc w/ large OADs when fitting K-cones? - Benefit = centration not an issue- Problems = harder to avoid excess areas of clearance and bubbles under OZ; adequate edge clearance more of a challenge
What K-cone RGP involves computer-assisted fitting? Keratoconus Bi-Aspheric (KBA)
For Rose K fits, what BC should you start with when fitting your K-cone patient? Avg K to 0.2mm steeper for initial lens
K-cone RGP OAD is usually (smaller/larger) vs typical RGPs? Why? smaller (better for tear exch)
SynergEyes Hybrid CL (fill-in):- OAD = ___mm- Center = ___mm- Center material = ___- Center Dk = ___- ___% water soft skirt 14.5 mm OAD8.2 mm centerParagon HDS 100 Dk rigid center30% water soft skirt
T/F - K-conus does not typically affect the mid-peripheral and peripheral corneal topography. True
What is the most common bilat sign of K-conus? Fleischer's ring (bottom left pg 3)
T/F - An "ideal" RGP fit on a K-cone involves a sag height of BC that is less than the sag height of the cornea. False - sag height of BC to EQUAL or SLIGHTLY EXCEED sag height of cornea
T/F - An "ideal" RGP fit on a K-cone involves no excessive areas of tear/debris pooling under the OZ. True
What pigmentation is involved with K-cones? Fleischer's Ring - usually at base of cone, iron deposit; easier to find when dilated
What is the primary mode of correction for mild K-conus? spectacles
In rose K, OZ (incr/decr) as BC is prescribed steeper. decr
How do you extend your keratometer's range for a K-cone? Use +1.25 D and add 8.00-9.00D to the drum reading.(+2.25D add = ~16.00D to drum reading)
T/F - The Rose K RGP design minimizes the amount of tear pooling around the base of the cone. True
Where is K-conus localized? Ectasia in central or inferior cornea
CLEK study: Asthma = __% 15
What is Munson's Sign? When the cornea of a K-cone pushes enough on the lower lid to make the lid protrude when looking down.
T/F - Blindness can occur with K-conus. False
What kind of blend is indicated for K-cone RGPs? medium
T/F - Bubbles are acceptable in K-cone fits since there is a moderate amount of clearance around the cone. False - want the steepest apical touch lens, but avoid bubbles.
K-cone VA: __% were 20/__ or better thru CLs__% were 20/__ or better through manifest refraction. 88%, 20/4058%, 20/40
T/F - Can use piggyback if see 3-9 staining in your K-cone patient. True
SynergEyes Hybrid Cl is approved for what conditions? - Post-surgical- K-cones- Multifocal
How do you determine the SCr in K-cone RGPs? Typically given as normal since mid-periph and periph usually unaffected, but change SCr based on amount of periph clearance seen (want to maximize)
What is the prevalence of atopy in the general population? 10-20%
What is the hereditary pattern of K-conus? AD w/ variable penetrance
What SCr is typically suitable for K-cones? 8.50 mm (range from 8.00-9.00)