Knowledge Base
2. Linking EyeSpace to your topographer

2. Forge Ortho-K Quick Start guide

5. Forge Ortho-KCharl Laas

The Forge Myopia lens is an Orthokeratology lens for the treatment of low to high myopia and astigmatism. It is available in rotationally symmetric, toric and quadrant-specific variants.

Lens Parameters:

EyeSpace Forge Rotationally Symmetric:

BOZR (mm) / Z-Zone (μm) / AC (mm)/ Diameter (mm) / BVP
e.g. EyeSpace Forge: 8.8 / 330 / 7.90 / 11.00 / +0.75

EyeSpace Forge Toric:

BOZR / Z-Zone / AC / Diameter / BVP

BOZR / Z-Zone / AC

e.g. EyeSpace Forge Toric: 8.8 / 330 / 7.90 / 11.00 / +0.75

8.9 / 345/ 7.75 /

EyeSpace Forge Quad:

BOZR0 / Z-Zone / AC / Diameter / BVP

BOZR90 / Z-Zone / AC

BOZR180 / Z-Zone / AC

BOZR270 / Z-Zone / AC

e.g. EyeSpace Forge Quad: 8.8 / 330 / 7.90 / 11.00 / +0.75

8.9 / 345 / 7.75 /

8.8 / 335 / 7.85 /

8.9 / 355 / 7.65 /

To start the design process start EyeSpace and follow these steps:

Select your Patient

A. Import your topography maps from your Medmont E300 topographer, Oculus topographer or Oculus Pentacam and then search for the patient by entering their name or surname.


B. Click on the menu option to import Medmont or EyeSpace export files, alternatively, you can create a patient and then enter corneal data manually to create a reference map.

  1. Manually import either EyeSpace (.eye) or Medmont E300 (.mxf) export files into EyeSpace.
  2. Create a new patient.
  3. Manually enter Corneal Data.
  4. Log out of your EyeSpace account.
  5. Exit EyeSpace.

Lens Design

  1. Select either the right or left design button.
  2. Select the topography map you want to use.
  3. Click ‘New Lens’.

The ‘New Lens’ window will open. Select the Forge Ortho-K icon and enter the HVID. The 'Refraction Type' dropdown box offers two options, 'Spectacle Rx' **and 'Refraction Over Lens'. Typically you will use the 'Spectacle Rx'** option when fitting Forge Myopia Ortho-K lenses.

  1. Select the Forge Ortho-K lens design.
  2. Enter HVID.
  3. Enter spectacle prescription.
  4. Click ‘Done’.

Lens Design Page

The lens design page is divided into three main sections.

The lens navigation menu shows a list of all the captured topography maps and lens designs for that particular patient.

Topography Map

  1. Left click on the topography map to view the topographical data.
  2. Left click on the drop-down list to switch the display to either a Tangential, Axial, Corneal Height or Elevation map.

Lens Design

  1. Left click on the lens design to view the design page.
  2. Right click on the lens design to duplicate or delete the design.

B. Corneal, refractive and lens design data

  1. Corneal data.
  2. Spectacle prescription / diagnostic lens and over refraction data.
  3. Basic lens design parameters.
  4. Advanced lens design parameters.
  5. After adjusting the BOZR, Z-Zone, or AC use the ‘Optimize AC and Z-Zone’ button to restore the ideal lens-to-cornea fitting relationship.
  6. After adjusting any of the lens parameters, use the ‘Apply’ button to resimulate the lens design without optimising the lens-to-cornea fitting relationship.
  7. Once the design is complete, use the ‘Add to Cart’ button to place the lens order in the shopping cart.

C. Simulation section

At the top of the simulation section, five tabs are available providing more in-depth information regarding the lens design and lens-to-cornea fitting relationship.

A. Simulation

  1. By default shows the tear film profile of the horizontal meridian or the meridian specified by clicking on the NaFl lens simulation shown in the bottom half of the simulation screen (see point 6).
  2. Shows the tear film profile with a 90-degree angle in respect to the meridian shown above.
  3. Lens simulation which correlates with the NaFl pattern as observed when the lens is placed on the eye.
  4. The blue areas represent the area of lens bearing on the cornea.
  5. The average central Tear Film Thickness (cTFT).
  6. Shows the specific tear film thickness under the lens at the point of click. Clicking on this point will also change the meridian used for the tear film cross-section by drawing a line from where you have clicked through the centre of the cornea and then plotting that cross section (see Point 1).

B. Tilt and Position

The tilt, position, and stabilisation controls are now available in a separate tab. As before, adjusting these values does not change the lens parameters. Aim for equal lens bearing (blue zones) over the horizontal meridian, or a three-point touch, in the alignment curve zone.

  1. Unchecked, EyeSpace will automatically calculate the tilt of the lens. As a practitioner, you can decide if the tilt looks realistic, and in case it is not, manually change the tilt value.
  2. The tilt buttons show the principal meridians of the lens. Clicking on the tilt buttons will change the tilt value by 0.05 increments/decrements.

More Reading:

For more information on lens tilt please read the following articles:

C. Optical Analysis

The optical analysis tab helps to visualise the optics of the cornea, tear lens system, and the final lens power. The plot shows the power of each element in air along each corneal meridian.

  1. The Ocular Refraction power (OR) shows the patient's contact lens prescription (vertexed spectacle prescription). For example, a patient with spectacle prescription -3.00D and vertex distance 12.0 mm will have an ocular refraction -2.90D.
  2. Tear power is the power of the tear lens formed between the cornea and the posterior surface of the contact lens.
  3. Ideal BVP is the ideal back surface power of the lens required to correct the patient's refractive error. This needs to take into account the tear power and is simply the ocular refraction minus the tear power.

D. Lens Schematic

  1. Lens sagittal height graph.
  2. Lens information (sagittal height, radius of curvature, and angle) at a given chord in the four quadrants of the lens.

E. Notes

Journal for clinical notes regarding the lens design and fit.


Clicking the ‘Add to Cart’ button will display a dialogue to confirm the back vertex power of the lens. EyeSpace will automatically calculate the recommended values, which can be modified if clinically necessary.

  1. Back Vertex Power (BVP) is the power of the lens in air. EyeSpace automatically calculates the ideal BVP of the lens, and you will not need to make adjustments to this value unless troubleshooting is required.
  2. Shows the Residual Astigmatism as calculated with the lens on the eye. If the residual astigmatism is more than -0.75Dc the visual acuity of the patient will be compromised. Revisit the corneal data, spectacle prescription and lens design for accuracy and if the residual astigmatism is still present rather place the order under review to allow your lens consultant to assist you with the fit.
  3. Places the final order in the shopping cart.
  4. Cancels the order, but will NOT delete the lens design data.