The I Kone LensManufactured in

Boston XO®

Valley CONTAX

Springfield, OR

Contact Lens Fitting Goals for Keratoconus

• Vision• Comfort• Corneal Health• Fit / Centration• Happy Patient

Selecting the Best Contact Lens Option

• Assessment of all of the Information– History includes lens failures & why ! – Spectacle Rx, Keratometry,

Topography– Size, shape, location of effected area

Modern Keratoconic Corneal Lenses

• Fitting – standardized– trial lens sets or topography – realistic increments

• Troubleshooting– logical, incremental changes– flexibility

A Systematic approach to:

I-Kone Design

• Anterior and posterior aspheric design.

• 10.4 mm, 9.6 mm, 8.8 mm • Boston XO®• Adjustable periphery• 14 lens fitting set

Diagnostic FittingI-Kone Keratoconus Design

Initial Base Curve fit on “Steep K” reading1. centration2. central clearance

Example:K’s 52.25 / 57.50 @ 45 5.92 mm (57.00 D)

9.6 mm diameter

Effect of

the

Base curve

Effect of

the

Base curve

I KoneEffect of Peripheral Curve

1 Step Flatter

2 Step Flatter

3 Step Flatter

The Keratoconic Cornea

• Assessment of ectatic area– Size – Location – Shape– Degree of Irregularity

The Keratoconic Cornea

• Assessment of ectatic area– Keratometry– Photokeratoscopy– Topography– Fluorescein Pattern Analysis– Slit Beam– 90 degree spin

Corneal Irregularity Keratometric View

The Keratoconic Cornea

• Assessment of ectatic area– Keratometry– Photokeratoscopy– Topography– Fluorescein Pattern Analysis– Slit Beam– 90 degree spin

Corneal IrregularityPhotokeratoscopic View

The Keratoconic Cornea

• Assessment of ectatic area– Keratometry– Photokeratoscopy– Topography– Fluorescein Pattern Analysis– Slit Beam– 90 degree spin

Corneal Irregularity Topographic View

Corneal Topography in Keratoconus

The Keratoconic Cornea

• Assessment of ectatic area– Keratometry– Photokeratoscopy– Topography– Fluorescein Pattern Analysis– Slit Beam– 90 degree spin

Advanced Keratoconus

The Keratoconic Cornea

• Assessment of ectatic area– Keratometry– Photokeratoscopy– Topography– Fluorescein Pattern Analysis– Slit Beam– 90 degree spin

Corneal Irregularity Slit Beam View

The Keratoconic Cornea

• Assessment of ectatic area– Keratometry– Photokeratoscopy– Topography– Fluorescein Pattern Analysis– Slit Beam– 90 degree spin

90 Degree Spin

Classifications of Keratoconus

• Shape– Mild < 45.00 D average K– Moderate 45.00 -> 52.00 D average K– Advanced 52.12 -> 60.00 D average K– Severe > 60.00 D average K

• Size– Nipple < 5 mm– Oval 5 -> 6 mm– Globus > 6 mm

Keratoconus

Nipple Shaped Keratoconus

Oval Shaped Keratoconus

Keratoglobus

Keratoconic Corneal Lens Options

The First Generation

• Soper (circa 1970)

– 1st significant KC design– Steep, fixed POZ

• McGuire Lens (circa 1980)

– Like Soper but multicurve

Keratoconic CornealLens Options

The Second Generation

• Valley Kone (Valley Contax, 1990)

– Smooth, continuous back surface• Rose K (Lens Dynamics, 1990)

– POZ varies with BC– Standardized fitting system

• Rose K II (Blanchard, 2005)

– Aspheric front surface to reduce Spherical Lens Aberration

Keratoconic Lens Optionsthe Third Generation

• I-Kone (Valley Contax, 2005)– Bi-surface aspheric– Balanced zone design

(central zones to fit cone area)– BC radius varied to achieve fit– Periphery fits non-ectatic area

Keratoconic Lens Optionsthe Third Generation

Balanced Zone Design• As BC radius steepens • POZ decreases• While Second Aspheric Width Increase• Eccentricity of Zones Increase

Advantages of fitting the I Kone Design

• Central Fit– extends the concept of 3 point touch– high eccentricity back surface spreads bearing

• Vision– front surface eccentricity to CANCEL out

aberrations induced by eccentric BC – and reduces other aberrations

• Comfort– reduced pressure points

• Corneal Health– Excellent tear flow

More advantages of fitting the I-Kone Design

• Aspheric Optics– Controls spherical aberration– Reduces lens mass

• Larger Diameter– Distributes weight more evenly across

corneal surface– Reduces glare / halos– Improves lens stability

The I Kone Lens14 Lens Diagnostic Set

Manufactured in

Boston XO®

Diameter Size: 9.6

Diopter Range: 44.00D to 70.00D

Valley CONTAX

Springfield, OR

800-547-8815