G424 – Contact lens fitting
OHIP Diagnostic & Therapeutic Procedures Code — DIAGNOSTIC AND THERAPEUTIC PROCEDURES · Schedule of Benefits
The G424 service covers contact lens fitting and includes all necessary follow-up care for a 3-month period after the initial fitting. As an exception, for children under 4 years of age, follow-up services are payable separately. A note in the Schedule on page specifies that contact lens fitting is not a benefit except under certain specific conditions, and physicians are advised to check with a Ministry of Health Medical Consultant to confirm eligibility before providing the service.
When to Use
- Use G424 for patients with documented keratoconus or aphakia requiring medically necessary contact lens fitting.
- Use G424 for patients with high myopia exceeding 9 diopters or irregular astigmatism secondary to corneal grafting or scarring.
- Use G424 when the fitting is medically indicated, as opposed to G423 which is restricted to specific diagnostic scenarios.
Common Pitfalls
- Billing G424 for cosmetic contact lens fittings will result in rejection or clawbacks, as these are strictly uninsured services.
- Submitting claims for follow-up visits within 90 days of G424 for patients over age 4 will trigger automatic rejection due to the global period.
- Failing to document the specific underlying diagnosis (e.g., keratoconus) in the patient record creates a high risk for audit recovery.
Billing Tips
- For patients under age 4, bill follow-up visits separately using appropriate office visit codes, as they are exempt from the 90-day global period of G424.
- Always verify the patient's refractive error or corneal condition meets the specific criteria listed in section J89 before submitting the claim to avoid Ministry of Health audit flags.
Effective: April 1, 2025
J. Diagnostic and Therapeutic Procedures
DIAGNOSTIC AND THERAPEUTIC PROCEDURES
Procedure
Diagnostic and Therapeutic Procedures
Contact lens fitting (G424 and G423) is only insured for the following indications: i. aphakia, ii. myopia greater than 9 diopters, iii. irregular astigmatism resulting from post corneal grafting or corneal scarring from disease, or iv. keratoconus.
Contact lens fitting performed for other indications is an uninsured service
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