Metro Optics Blog

This patient was brought in by local practitioner for keratoconus fitting with ComfortKone. Topography confirmed keratoconus OU and trial lenses were selected according to Steepest “SimK Values”.

Topography OD

Topography OS

OD – Base Curve 6.60, Power -5.00, Diameter 8.5, A-Value 10

OS – Base Curve 6.30, Power -8.00, Diameter 8.5, A-Value 15

Evaluation showed mild central pool with a thin band of fluorescein around edges OU. Less edge clearance was noted on OS versus OD.

Fluorescein pattern OD

Fluorescein pattern OS

Conclusions:  Base Curve fit is acceptable OU.

More edge lift is needed so higher A Values should be used.

Over-refraction was -.50 OD and -.75 OS.

Prescriptive lens specifications:

OD – Base Curve 6.60, Power -5.50, Diameter 8.5, A-Value 12

OS – Base Curve 6.30, Power -8.75, Diameter 8.5, A-Value 16

Patient presented with highly irregular corneal graft. Inferior region has two distinct areas of protrusion and can be seen in topography images 1 & 2.

Image 1

Image 2

Prior to visiting our facility, multiple attempts had been made to fit this eye with base toric lenses. All of which failed to achieve an acceptable fit.

Although topography readings are achievable, they fall short of complete accuracy of curvature.

Our initial design featured the following parameters:

Primary Base Curve Radius  = 6.20

Two offset zones, each 2mm from inferior center with Radii of 5.40 and a diameter of 4mm.

Lens Power  = -9.25

Overall lens diameter = 9.2mm

This lens produced a 20/30 visual acuity and the fluorescein pattern is featured in image #3. Although this is not a good fit it helped us quickly determine parameter changes for a much improved fit.

Image 3