Article Date: 7/1/2003

ORTHO-K INVENTORY
Advanced Inventory Orthokeratology System
One practitioner explains how a system of inventory orthokeratology lenses improved his success with ortho-k fitting.
By Donald H. Harris, OD, MS, FAAO

As a specialized orthokeratology practitioner for 31 years, I have used many orthokeratology designs and systems in my practice. I find that the Vipok Inventory Orthokeratology system (Vipok, Inc.) offers the most accurate and efficient means of orthokeratology lens fitting.

Vipok lenses are relatively new to the contact lens market. They are four-curve, double reverse geometry lenses that are designed for orthokeratology. The computerized mathematics and design principles used to develop the Vipok lens design are truly different. This system uses a simple reference chart for lens selection. Practitioners can use subjective spherical equivalents and mean corneal curvature measurements to choose the proper lenses. This system allows both novice and expert practitioners to easily and confidently manage ortho-k cases.

Figure 1. Post-treatment corneal topography of a patient who achieved his desired visual result with the initial ortho-k lenses.

The Vipok system consists of a fitting inventory set of 168 orthokeratology lenses. According to the manufacturer, this inventory set would fit 85 percent of all orthokeratology cases. The fitting set allows practitioners to make lens adjustments and dispense new lenses on the same day if they choose to do so.

Practitioners can also purchase a 24-lens Vipok inventory set, or they can order lenses from the manufacturer on a per-case basis.

The manufacturer claims that its newer Vipok XC lenses feature a patented lens design which allows changes of up to ­10.00D in myopia with just one pair of lenses.

Case Studies

I decided to research the accuracy and success of the Vipok orthokeratology inventory system. In addition, I wanted to test the system's simplicity, ease of fitting and problem-solving capabilities for orthokeratology patients.

I started 50 new orthokeratology patients on the Vipok inventory orthokeratology system. I present the results of five of these patients in this article.

Figure 2. Post-treatment corneal topography of a patient who achieved 4.50D refractive change OD and 4.25D refractive change OS.

Case #1

The first patient was a 39-year-old corporate CEO of a public company. He chose orthokeratology over refractive surgery. This patient achieved his desired visual results with only one lens per eye. Most of his corneal changes occurred within the first four days of treatment. Table 1 details his corneal changes over a three-month treatment period. Figure 1 shows his post-treatment corneal topography after four weeks of wear. He is now a happy patient who wears his lenses overnight five nights a week. He can perform all of his business and recreational duties all day without lens wear.

Case #2

The second patient was a 19-year-old college student who had progressive myopia. He was interested in slowing his myopia progression. This high myope and previous gas permeable lens wearer may still consider refractive surgery in the future.

The orthokeratology lenses I prescribed helped reduce his myopia and improved his unaided vision. He gained functional vision without wearing his lenses and could perform many activities with unaided vision. His fit required only one lens change to achieve better lens centration. Table 1 details his corneal changes over a three-month treatment period. He achieved 4.50D of refractive change in his right eye and 4.25D of change in his left eye (Figure 2).

Figure 3. Corneal topography of Patient #3's right eye before ortho-k lens wear (left) and three days after initiating treatment.

Case #3

The third patient was a 30-year-old college student who has moderate to high myopia. Her refractive changes with the Vipok lenses occurred very quickly (Table 1), and she was pleased with her unaided vision. This patient required only one lens change to improve lens centration. She currently wears the lenses only at night and functions without any lens wear during the day. She maintains good unaided vision for up to 16 hours daily. Figure 3 shows the corneal topography of her right eye before treatment and after three days of treatment.

Figure 4. Post-treatment corneal topography of a patient who achieved 20/20 unaided VA OU within two days of ortho-k lens wear.

Case #4

The fourth patient was a 20-year-old male who is in the military. He wanted to enter flight school, but could not because he had 20/200 vision in both eyes. He wanted to become a flight candidate and he was interested in improving his unaided acuity so he could pass the vision test requirements. Within one month of treatment with orthokeratology lenses, he achieved 20/20 vision and he passed the flight school vision test. He now has unrestricted FAA clearance for flight vision testing. Most of the change in his vision occurred within two days of lens wear (Table 1). This patient required no lens changes. Figure 4 shows his corneal topography following two days of treatment.

Case #5

The fifth patient is a 14-year-old 8th grade student. At his early age he had already shown high myopia changes. His parents were concerned about his progressing myopia and wanted some method of myopia control. After I fit him with the Vipok lenses, his unaided vision improved from 20/500 to 20/70 in the right eye and from 20/400 to 20/60 in his left eye in a very short time (Table 1). Figure 5 shows his corneal topography before treatment and after two weeks of treatment.

Figure 5. Corneal topography of a patient before ortho-k lens wear (top) and after two weeks of lens wear.

Practice Benefits

I find the Vipok orthokeratology inventory system simple and easy to use. It is efficient and effective, and it saves chair time. Its in-office convenience allows you to troubleshoot lens fits on the spot and in a timely manner. The system includes simple directions to troubleshoot from inventory, and I found the adjustments simple and accurate. The Vipok system provided me with more exact and predictable results than I've experienced with custom-order lenses. Because you can make precise changes from inventory, you can solve fitting problems with better control. I've achieved more patient success and satisfaction as a result.

With the inventory method, I no longer experience lens ordering mistakes, laboratory errors and patients waiting for their lenses. I've found that convenience for the patient is a major reason this inventory system is a success. You can solve difficult fitting problems immediately, and the patient does not have to wait three to five days for a new lens. This is helpful, and it also increases patients' confidence and trust in their eyecare practitioners.

As an experienced practitioner who has used most orthokeratology systems for over 30 years, I found that the Vipok inventory system was simpler and more accurate than all other orthokeratology lens systems. In fact, my success rates were higher from the initial fitting. Learning to use this inventory system was simple and easy. I think this system is ideal for novice practitioners who want to introduce orthokeratology into their practices.

Dr. Harris is in private practice in Newport Beach, CA. A past chairman of the International Orthokeratology Section (IOS) of the National Eye Research Foundation (NERF), he has used orthokeratology in his practice for more than 30 years.

 


Contact Lens Spectrum, Issue: July 2003