Orthokeratology can be a fun and satisfying procedure to perform in your practice and done successfully will bring you many loyal and devoted patients over the years.
EyeSpace has made the procedure of orthokeratology a straightforward and visually intuitive process. However, the software is only as good as the provided data. It is of vital importance to take good topography maps, perform accurate refractions and above all choose the right patient.
This article provides a basic guideline to complete the fitting process of EyeSpace Forge Ortho-K lenses.
Taking good topography maps
- Calibrate your topographer regularly.
- Capture several geometrically centred maps.
- For dry eye cases, instil a single drop of artificial tears five minutes before map capture.
- Inspect the Placido disc image for any capture defects caused by a sparse tear layer (ring jam) or shadows caused by eyelids. Should errors occur recapture the map.
- If it is not possible to take a good topography map due to a severely dry and inflamed eye, discontinue the topography session and first treat the ocular condition. Manage the pathology first and then resume the topography capture.
- Wash out the cornea from any previous contact lens wear. It is best to see the patient first thing in the morning with no soft lenses worn to the appointment.
- Read the article, Capture of Corneal Topography maps for more tips on how to take good topography maps
Choosing your ideal Orthokeratology patient
It is essential to choose the right patient and corneal shape to achieve the best results with orthokeratology
Corneal conditions suitable for Orthokeratology
- Natural corneal shape, free of pathology and corneal scarring.
- Normal pupil size. Patients with large pupil sizes will experience increased halos and glare at night.
Corneal conditions NOT suitable for Orthokeratology
- Corneas where the corneal astigmatism doesn't match the refractive astigmatism in magnitude or direction by greater than 1.00D or 20 degrees. For more information read the Correcting toric prescriptions with orthokeratology article.
- Any corneal dystrophy like keratoconus, pellucid marginal degeneration, endothelial dystrophy, etc.
- Any corneal scarring due to injury or disease.
- Penetrating Keratoplasty (grafts).
- Radial Keratotomy (RK).
Good social influences
- Good personal hygiene.
- Well motivated and cooperative.
- Will be compliant with the required cleaning and follow up appointments.
- Age-appropriate, mature and responsible.
- Motivated by sport, e.g. water sports, outdoor activities, contact sports.
- Motivated by occupation, e.g. law enforcement, military, lifeguard.
Bad social influences
- INTP or 'Engineer' personality types or persons with unrealistic visual expectations.
- Vocations with on-call work schedules leading to irregular sleep patterns, for example, rescue services, medical or aviation. Most - especially high prescription - Ortho-K fits require more than 4 hours of uninterrupted sleep to reshape the cornea successfully.
- Persons with poor hygiene routines.
- Immature or fearful person.
Modern orthokeratology can fit a wide range of refractive errors. However, some prescriptions require more experience. Depending on your level of experience, use the guide below to help you determine if you should attempt the orthokeratology fit, solicit the help of a mentor or instead refer to a more experienced fitter.
Beginner experience level
- Sphere powers between -0.25D to -4.50D
- Astigmatism between -0.25D and -1.50D
Intermediate experience level required
- Sphere powers between -4.50 to -6.50
- Astigmatism between -1.50D and -3.50D
- Regular Post LASIK
- Hyperopia between +0.25D to +4.00D
Advanced experience level required
- Sphere powers between - 6.50 and -8.00D
- Astigmatism above -3.50D
- Residual astigmatism above -0.75D
- Hyperopia between +4.00D to +5.00D
- Hyperopic compound astigmatism
- Irregular post LASIK
Designing your Forge Ortho-K lens
- To familiarise yourself with designing the Forge Ortho-K lens, review the Forge Orthokeratology Quick Start Guide.
- With a good capture quality and geometrically centred topography map, EyeSpace should design a Forge Ortho-K lens requiring very little to no user modification.
- Usually, all that is required is to tilt the lens until the blue lens-corneal bearing zones under the alignment curve are balanced over the horizontal meridian.
- When the alignment curve lens-corneal bearing zones are balanced, click the 'Optimize Z-zone and AC' button, and EyeSpace will optimise the lens design.
- Should the lens design not look correct, revisit all the information listed above, starting with taking good topography maps.
Dispensing Forge Ortho-K lenses
- Forge Ortho-K lenses should be inspected and cleaned well before dispensing.
- Verify the lens engraving against the EyeSpace Members website.
- Place one drop of a preservative-free solution with NaFl in the back of the lens
- With the patient in a face-down position, insert the lens directly onto the cornea. If bubbles are present under the lens, remove and reinsert.
- Allow the lens to settle and assess the lens centration and movement.
- As with regular corneal lenses, the lens should move vertically by about 1.50 - 2.00 mm with each blink.
- Once the lens has settled, ask the patient to sit with their eyes closed for 15-30 mins. Please note new wearers may need longer settling time (30 mins) due to blepharospasm and epiphora.
- Paste the provided EyeSpace labels into your record card.
- Familiarise yourself with the NaFl simulation in EyeSpace. The actual NaFl pattern should look the same as the EyeSpace simulated NaFl pattern.
Initial Lens Assessment (after 15-30 mins)
- It is normal to experience some foreign body sensation due to the eyelids moving over the edge of the lens during blinking.
- Observe the NaFl pattern with your slit lamp using the Kobalt blue light with a yellow Wratten filter attached.
Hold the eyelids and manipulate the lens to a central position for the best assessment of the lens alignment observing the NaFl pattern.
- Where possible, it is good practice to photograph the NaFl pattern in a central position for use when sending to your distributor for troubleshooting.
- Note the position and stability of the lens markings for toric designs.
- Perform a refraction over the lens (ROL).
- Remove the Forge Ortho-K lens.
- Capture a well-centred topography map.
- When reviewing the initial post fit map it is unlikely the full orthokeratology reshape will be present, but an underdeveloped corneal reshape pattern should begin to show.
- Using the Axial Power map, verify the treatment zone has centred and formed in the pupil zone.
- Provide the patient with Care and Maintenance instructions.
Use the EyeSpace Ortho-K insertion and removal tutorial video to train the patient how to insert and remove the Forge Ortho-K lenses before sending them home.
Next day follow-up
- The patient must remove their Forge Ortho-K lens first thing in the morning on awakening.
- A proper removal technique is first to drop an artificial tear in the eye and then, using the bottom eyelid, nudge the lens to break the overnight seal. Once the lens moves freely with blinking, it can be safely removed. Using this technique minimises the risk of detaching the superficial epithelial layer, which can be adherent to the lens surface after overnight wear and clinically observed as faint central staining after lens removal, subsiding as the day progresses.
- Instruct the patient to bring their lens to the follow-up visit, in case you need to inspect them or place them on the eye.
- Capture a corneal topography map.
- Question the patient about their first experience sleeping with the Forge Ortho-K design.
- Answer any questions or concerns they might still have.
- Reinforce the correct insertion, removal and cleaning techniques. See Care and Maintenance instructions.
- Stain the cornea with NaFl and verify the absence of corneal pathology - for instance, staining, infiltrates and ulcers.
- The presence of staining can be multifactorial. Please read this article regarding central staining.
- If everything appears to be on track, send the patient home and schedule a follow-up procedure within two weeks.
- Perform corneal topography.
- Measure monocular unaided vision at distance and near.
- Measure the residual refraction.
- Slit-lamp assessment of the ocular surface with NaFl to check for corneal staining or other pathology.
- Assess the lens for defects, scratches, chips, depositing.
- Reinforce the correct insertion, cleaning and removing techniques. See Care and Maintenance instructions.
- Schedule a follow-up procedure within two weeks until the fit is complete.
Tip: Many troubleshooting issues are associated with poor topography maps. Take your time and learn the art of taking good topography maps with your topographer. To help, review the Capture of corneal topography maps article.
If, after an appropriate amount of time, the desired corneal reshaping outcome is not achieved, you can log a troubleshooting report. Log in to the EyeSpace Online portal and search for the order page of the lens you are troubleshooting. At the bottom of the order page, complete the online troubleshooting form. For your support representative to assist you, it is vitally important to provide all the required information listed on the Ortho-K Troubleshoot Form: