LENS DYNAMICS, INC.. SCLERAL HISTORY Original contact lens Hand ground glass lenses Fit by casting a...
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Transcript of LENS DYNAMICS, INC.. SCLERAL HISTORY Original contact lens Hand ground glass lenses Fit by casting a...
LENS DYNAMICS, INC.
SCLERAL HISTORY
• Original contact lens
• Hand ground glass lenses
• Fit by casting a mold of the cornea
EARLY SCLERAL PERFORMANCE
• Difficult to fit
• Hard to manufacture and reproduce
• Corneal hypoxia
• Very short wearing times
• Corneal molding – The negative kind
SCLERAL DEFINED
• Mini-Sclerals – 12.5mm to 14.5mm
• Medium Range Sclerals – 15.0mm to 18.0mm
• Full Sclerals – 18.5mm to 28.0mm
SCLERALS – FIRST OR LAST RESORT?
WHY FIT A SCLERAL LENS?
THE PRO:
• To vault highly irregular corneas
• To provide better visual acuity than soft lenses
• To prevent lost lenses
• New Oxygen permeable materials
WHY FIT A SCLERAL LENS?
THE CON:
• Harder to fit
• Harder to insert and remove
• Can reduce metabolic waste removal
• Potential for hypoxia
• Harder to fit
THE PRACTICAL:
• First or Last Resort as a design?
• Who fits sclerals at all?
• Who fits sclerals as the design of First choice?
• Who fits sclerals as a design of Last resort?
THE DESIGN:
• 13.0mm, 13.5mm, 14.0mm
• Lathe cut on DAC ALM lathes
• Spherical back and front surfaces
• Normally NOT fenestrated
HOW TO FIT
• Start with a base curve close to average Ks
• Trial for best alignment pattern as possible
• Be sure there is NO conjunctival drag
• Do spherical over-refraction
• Need 0.5mm of movement
FITTING TIPS
• Fill concave side with saline/wetting drops into posterior of trial lens
• Dip fluorescein strip into solution
• Insert using 2 fingers to handle the trial lens with patient looking at floor
• Low riding lens – select flatter base curve
• Flatten base curve to solve edge tightening
CASE HISTORIES
48 years old, Caucasian male, OD cornea
• Can’t use bi-toric• Quadrant Specific
base curve not indicated
• Temporal/superior area eliminates reverse curve design
• Select Semi-Scleral 13.5 design
CASE 1
48 years old, Caucasian male, OD cornea
• Average K is 47.00 D. or 7.18mm
• Select 7.20mm BC from trial set, 13.5mm -4.00
• Acceptable fit with -2.25 over-refraction
CASE 1
22 years old, African American male, OS cornea
CASE 2
• Superior, peripheral area too steep for Quadrant Specific base curve
• Bi-toric not indicated• Select Semi-Scleral
13.5 design
22 years old, African American male, OS cornea
• Average K is 47.00 D. or 7.18mm
• Select 7.20 BC from trial set, 13.5mm
• Lens too tight at edge and too much vaulting
CASE 2
22 years old, African American male, OS cornea
• Select trial lens 0.2mm flatter or 7.40mm
• Acceptable fit• Perform spherical
over-refraction
CASE 2
31 year old Caucasion female, OD cornea
• Bi-toric not indicated• Flatter areas too
narrow for Quadrant Specific base curves
• Reverse curve design not indicated
• Select Semi-Scleral 13.5 design
CASE 3
31 year old Caucasion female, OD cornea
• Average K is 46.25 D. or 7.30mm
• Select 7.30mm trial lens from trial set
• Low riding lens-select flatter base curve
CASE 3
31 year old Caucasion female, OD cornea
• Select 7.50mm base curve from trial set
• Acceptable fit with lens properly positioned
• Perform spherical over-refraction
CASE 3
Questions?