How to Improve the Fitting of Soft Contact Lenses

– A Statement by a German Educator (but I am not alone!)

Peter Moest PhD

BERLIN - GERMANY

Introduction

At the recent European Academy of Optometry and Optics meeting in Malaga, we had a session of the Special Interest Group 4 ‘Cornea, Contact Lenses and Refractive Technology,’ with a lecture by Helmer Schweizer about fitting soft contact lenses. As a contact lens educator of the Beuth University, Berlin, one of the leading optometry schools in Germany, we have a special interest in fitting contact lenses, and therefore I joined the meeting.

Yes, we fit soft contact lenses, it is one of the most important parts of our education. We also fit disposable lenses. But first we teach the fitting of individual soft lenses to our students. This is not because we want to change the worldwide market, but rather we want to show our students the best possible fit of a soft contact lens for a given lens wearer. We have three requirements of nearly equal importance:

1.    Best possible vision
2.    Best possible oxygen supply
3.    Best possible tear film exchange

Statements

Based on these requirements, the statements below apply to our situation:

·       Yes, we fit soft contact lenses (as they represent more than 90% of the market)
·       Yes, it is an advantage to have disposable lenses.
·       Yes, most of the disposable lenses fit.
·       About a third of these lenses ‘could fit better.’

There are a number of reasons why about one-third of the lens fits fall in the ‘could fit better’ category. The first reason is diameter. The cohort of students in my last contact lens course (44 students) had an average corneal diameter of 11.8 mm; 15 students (one-third of all) had corneal diameters smaller than 11.5 mm. Every single disposable lens fit on these eyes fell into the category ‘could fit better.’

Another observation of the disposable lens fits at my university is that many demonstrate inadequate movement – they move, but not enough. Most of the disposable lens systems have only one base curve (compliments to J&J, Menicon and Bausch+Lomb – they offer two), which is reason number two why so many lens fits fall into the ‘could fit better’ category. If we fit toric or multifocal lenses, all have only one base curve. But we all know, especially with toric or multifocal lenses, it could be very helpful to have additional options to improve lens movement, stabilization or centring.

Wish List

To better serve our patients, we request that international contact lens manufacturers consider these points:

1.    A second (smaller) diameter is needed for disposable lens systems. We know from experience that smaller lenses can provide more tear film exchange. This would be better for the patients because it may reduce the risk of microbial keratitis.

2.    Provide more disposable lens systems with more than one base curve, especially for toric and multifocal lenses.

The argument of the past, that the number of lenses prescribed is too low to produce and sell them successfully, is no longer valid today (about 90% of the market is disposable lenses). The eyes of my students are not smaller, steeper or flatter than in any other place in the world.

“it could fit better”

If we estimate that the contact lens market in Germany has about 3.4 millions wearers, nearly 3 million people wear disposable soft contact lenses. If we assume for a moment that my students are representative for all, about 1 million people wear contact lenses that fall into the “it could fit better” category – a terrible thought.  

This is the reason why we joined the special interest group “Contact Lenses” in Malaga in April 2013, but I am not sure that the contact lens manufacturers heard and understood our “Help” message. We want in the future to be able to say to our students, practitioners and patients: “Yes, we can do better.”

Peter Moest PhD

Peter Moest is the head of the department of Contact Lenses at the Beuth University of Applied Sciences in Berlin, Germany. He studied physics in Berlin and received his PhD in physics also in Berlin - in 1988. Since 1989, he has been involved in contact lens education, first at the "SFOF Berlin,” which is now the Beuth University of Applied Sciences. He is a member of IACLE and of the German contact lens and optometric association VDCO.