Ortho-K Lenses for Myopia Management: A Comprehensive Guide

Ortho-K lenses offer an innovative solution for myopia management, reshaping the cornea while your child sleeps. Experience clear vision without glasses or contacts during the day.

Table of Contents

The Role of Ortho-K in Myopia Management
Lens Design and Customization
The Lens Fitting Process
Key Measurements
Safety and Best Practices
Ortho-K Lenses for Myopia Management: A Comprehensive Guide
Ortho-K Lenses for Myopia Management: A Comprehensive Guide
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The Role of Ortho-K in Myopia Management

Myopia, or nearsightedness, is an increasingly common condition in young people, where the eye grows too long or the cornea curves excessively, making distant objects blurry. With Ortho-K, specialized lenses are worn during sleep to temporarily reshape the cornea, helping to reduce the refractive error that causes nearsightedness while slowing the down the progression of myopia. This method not only corrects vision today, but protects your child's vision as they age by reducing the risks of vision threatening conditions from high myopia. Furthermore they offer benefits such as improved natural vision for sports, recreation, and professions that demand sharp unaided vision.

Lens Design and Customization

How Ortho-K Lenses Are Designed

The process of designing Ortho-K lenses starts with understanding the unique structure of your child’s eye. Our eye doctors begin by analyzing the curvature of the cornea through a painless procedure using a corneal topographer. This instrument creates a detailed map of the front surface of the eye, capturing critical measurements such as apical curvature, horizontal visible iris diameter (HVID), sagittal height, pupil size, and astigmatism.

Based on these measurements and your child’s prescription, a customized lens is designed using computer-aided technology. Each lens is a rigid gas permeable lens that is specifically tailored to gently apply the correct amount of pressure to reshape the cornea while being comfortable and safe for overnight wear. In many cases, more than one pair of lenses may be developed during the fitting process to ensure your child achieves the best possible vision correction.

Breaking Down the Customization Process

Designing a successful Ortho-K lens involves several key parameters that our eye doctors adjust to meet your child’s needs. Here’s an overview of the main modifications that can be made:

Compression Factor: This parameter is based on the concept of the “Jessen Factor,” which adjusts for the natural rebound of the cornea after lens removal. By designing a slight overcorrection, the treatment helps maintain clear distance vision throughout the day.
Back Optic Zone Diameter (BOZD): Adjusting the BOZD is used to fine-tune the treatment zone size. A smaller BOZD may be chosen to achieve a more focused correction, while careful changes are made to ensure that the lens fits comfortably without decentering the cornea.
Multifocal Optics Adjustments: In some cases, the lens may be designed with multifocal optics to enhance myopia control. Although this customization can lead to a slight decrease in visual acuity, it may prove beneficial for managing myopia progression over time.

Each of these adjustments is carefully considered by our eye doctors. Your child’s individual measurements, such as the curvature of the cornea and pupil size, allow us to simulate and predict the lens design’s effectiveness using specialized software. This process eliminates the need for lengthy in-office trial fittings, making the experience faster and more comfortable for your child.

The Lens Fitting Process

Step-by-Step Lens Fitting Process

The Ortho-K lens fitting process is a detailed, multi-step procedure that ensures both effectiveness and comfort. Here’s how our eye doctors approach it:

Initial Assessment: The journey begins with a comprehensive eye exam that includes a refraction test, tear film evaluation, and an assessment of the anterior eye segment. A corneal topographer is used to capture a detailed map of the corneal curvature.
Measurement Collection: Key data such as the horizontal visible iris diameter (HVID), apical curvature, astigmatism, sagittal height, and pupil size are recorded. These measurements are essential to determine if your child is a good candidate for Ortho-K lenses.
Custom Lens Design: Using the gathered data, our eye doctors input measurements into specialized software. This produces a computer-generated simulation of a lens that will create the desired change in corneal curvature.
Trial and Evaluation: Once the lenses are produced, your child will begin wearing them during sleep. On waking, the lenses are removed and your child’s vision is evaluated. Our eye doctors use advanced tools to inspect the lens fit and the bullseye pattern on the cornea, ensuring that there is a central 4 mm area of bearing with the appropriate edge lift.
Follow-Up Visits: Regular check-ups are essential in ensuring that the lens design continues to perform as expected and that your child’s corneal shape remains healthy. Adjustments to the lens design may be made based on these findings, allowing for gradual improvements in vision during the treatment period.

This methodical approach not only provides clear vision quickly—in many cases, improvements can be seen as early as the next day—but it also ensures that any adjustments needed over time are carefully managed.

Key Measurements

Key Measurements and Their Importance

To create a perfectly tailored Ortho-K lens, it’s crucial for our eye doctors to gather specific biometric data. Here are some of the most important measurements involved:

Horizontal Visible Iris Diameter (HVID): Often referred to as the "white-to-white" measurement, HVID helps determine the overall size of the lens required. It ensures that the lens covers the necessary area of the cornea for an effective reshaping.
Apical Curvature: This refers to the curvature at the corneal apex—the part of the cornea with the steepest curvature. Steeper apical curvature generally means there is a greater potential for corneal flattening, which is key to effective myopia correction.
Sagittal Height: The sag height is critical for matching the lens to the central thickness of the cornea. If the lens does not align well with the peripheral cornea, the entire lens may not stay centered, reducing treatment effectiveness.
Astigmatism: Evaluating the level of astigmatism is essential as it influences the decision between spherical and toric lens designs. High astigmatism may require a toric design to maintain an even fit around the cornea.
Pupil Size: Measuring both photopic (in well-lit conditions) and scotopic (in low light) pupil sizes is important. Larger pupils can sometimes accentuate visual effects such as glare and halos, especially under dim lighting conditions.

Collecting precise data from these measurements allows our eye doctors to design a lens that is uniquely suited to your child's eyes. Each parameter is cross-referenced to ensure that the final lens provides optimal vision correction while maintaining overall eye health.

Safety and Best Practices

Safety Considerations and Best Practices

Safety is paramount when it comes to Ortho-K lens treatment. Although all contact lenses carry some risk, studies have shown that the rate of infection with Ortho-K lenses is significantly lower compared to extended wear of soft contact lenses. Our eye doctors emphasize rigorous hygiene and regular follow-ups to minimize any complications.

Here’s how safety is maintained throughout the Ortho-K process:

Strict Hygiene Protocols: Before fitting lenses, thorough instructions on proper cleaning and handling are provided. Parents are also educated on the importance of following these guidelines to reduce risks.
Regular Monitoring: Frequent office visits are essential in spotting any early signs of complications, such as corneal staining. Monitoring the fit and overall health of the cornea ensures any issues are dealt with quickly.
Custom Fit to Prevent Decentration: A well-fitted lens should have minimal movement (ideally less than 1 mm) and proper centration on the cornea. This careful fitting process prevents complications such as lens decentration, which can lead to discomfort and reduced visual clarity.
Lens Material and Replacement: Only highly breathable FDA-approved lenses are used for overnight wear. The lenses are designed to be replaced every one to two years to maintain optimal performance and reduce potential risks.

The emphasis on safety goes beyond the initial fitting—continued education about signs of problems, such as redness, pain, excessive tearing, or decreased vision, is provided to parents. Our eye doctors encourage you to contact our office for personalized guidance if you notice any unusual changes.