Problems Flashcards
Giant Papillary Conjunctivitis (GPC)
Signs/Symptoms:
- large papillae under superior lid
- itch upon lens removal
- mucous discharge
- CL intolerance
- lens movement
- lens need replacement quickly
Treatment:
- temporarily discontinue/consider daily
- Pataday/Zaditor for mild
- topical steroid for severe
Contact Lens Overwear or CLARE (Contact lens acute red eye)
Signs/Symptoms:
- severe injection
- sterile subepithelial infiltrates (peripheral)
- pain
- photophobia (often upon awakening after wearing overnight)
- corneal edema (microcystic)
Treatment:
- discontinue
- use antibiotic (fluoroquinolone) or steroid combo
- cycloplegic/oral analgesic as needed
- Fit in SiHy
Infectious corneal ulcer
Signs/Symptoms:
- acute red
- painful
- photophobia
- corneal infiltrate with overlying epithelial defect
- corneal edema
- tearing
Treatment:
- aggressive fluoroquinolone (loading dose)
- close follow-up
- culture as needed
Tight-fitting Lens
Signs/Symptoms:
- lens becomes less comfortable after several hours
- redness
- long-term may cause signs of corneal hypoxia
Treatment:
- refit with a flatter lens
- add artificial tears and consider temporary break
Soft lens dryness/dessication
Signs/Symptoms:
- decreased comfort with extended wear time
- sandy feeling
- SPK usually in interpalpebral area
- protein coated lenses
Treatment:
- rewetting drops
- better fit
- refit with low water content lens (draws less water)
- thicker lens
- humidifier
Oxygen transmissibility
Dk/t
- lens thickness affects transmissibility
- thicker lens, lower transmission
Oxygen permeability
Dk
- increased water, decreases SiHy Dk, increases hydrogel
True or False:
PMMA has good oxygen permeability
FALSE.
No oxygen permeability.
Characteristics of a tight soft lens?
Mucin balls, central bubbles, poor comfort on insertion but improved comfort after wearing, improved vision after a blink, perilimbal injection after hours.
Characterstics of a loose soft lens?
Drops inferiorly, poor comfort especially with blink, blurred vision after blink which improves between blinks.
What is the classification system for all hydrogel materials by FDA?
Group 1: <50% water, nonionic
Group 2: >50% water, nonionic
Group 3: <50% water, ionic
Group 4: >50% water, ionic
Group 2 and 4 with high water content is good for extended wear.
Mucin balls, GPC and edge fluting are characteristic of..?
High modulus of elasticity!
Signs of solution sensitivity?
- GRADUAL onset of redness and iriritation
- may be stinging after lens insertion, faint/diffuse infiltrates may be present
What kind of fit?
Central touch with no fluorescein centrally, a broad green ring underneath the peripheral region of the lens.
Flatter than K.
What kind of fit?
Bull’s eye pattern, pooling in the apical region.
Steeper than K.
What kind of fit?
A figure 8 shaped pattern of touch vertically, pooling outside that region and in peripheral zone.
Fit over ATR cornea.
- vertical bearing
- horizontal pooling
What kind of fit?
A dumbbell shaped pattern of touch horizontally, pooling outside that region and in the peripheral zone.
Fit over WTR cornea.
- horizontal bearing
- vertical pooling
What kind of fit?
A dumbbell shaped pattern of touch horizontally, pooling outside that region and in the peripheral zone.
Fit over WTR cornea.
- horizontal bearing
- vertical pooling
Problems with low riding lens?
Can cause corneal dessication which is drying of corneal epithelium that typically occurs at 3 and 9 o’clock positions.
- lid attachment fit may decrease corneal dessication due to increase tear movement.
Problem with high riding lens?
It can cause corneal warpage.
What peripheral curve design is used to raise the lens?
Increase edge lift.
WTR astigmatism corneal topography would look like….
Figure 8 shape on corneal topography
ATR astigmatism corneal topography would look like…
Dumbbell shape on corneal topography
