reader and industry forum
The Two Most Important Lens Wear Considerations
BY MILTON M. HOM, OD, FAAO
Just like most of you, I distinctly remember my first day in contact lens clinic. I was a rookie clinician seeing a one-week soft lens progress visit. After presenting the case to my instructor, he stared me down and asked in a loud voice, "There are only two things I really care about. What are they?" After much hemming and hawing, I finally cobbled together the answer he was looking for. In my mind, he was a successful instructor that day because I learned something from him that I have not forgotten.
What were the two most important things he wanted to know? Vision and comfort.
Comfort Isn't Everything
Fast forward to today, and I still see in our industry a continued passion for understanding comfort during lens wear, almost to a fault. Comfort studies, questionnaires, and testimonials seem to be everywhere. Sometimes it can even become a bit confusing as it seems that every company has a study showing that its lens is more comfortable.
I think our over-attention toward comfort makes us forget about other important things, such as the other 50 percent of my instructor's concerns: vision.
Soft lenses have made enormous strides in vision correction over the years. I remember when toric lenses were available only in two cylinder powers. Now, we can fit large amounts of cylinder and amounts as low as 0.75D. The power range seems almost infinite for day-to-day practice.
I used to use a −0.75DC trial lens to demonstrate the improved vision that low-cylinder patients wearing spherical lenses could get with toric lenses. These days, I just place such patients into a low-cylinder toric; I rarely demonstrate anymore because the success rate is so high. For a patient who is still unconvinced after our discussion, a hand-held trial lens usually seals the deal. For me, masking the low cylinder by over-minusing seems a little sloppy because it does not provide the visual quality that a toric lens offers.
Better Vision, Better Comfort
In some cases, comfort can be related to vision. Uncorrected astigmatism, masked cylinder, and even monovision can contribute to asthenopia and overall discomfort with lenses.
For presbyopes, I have abandoned monovision and use multifocals almost exclusively. In the past I liked multifocals because of the better stereopsis and overall concept, but the designs didn't seem to be quite right. I think the bane of multifocals in the past was distance vision. No more. I have seen 38-year-olds with eyestrain at near who don't want to wear reading glasses or bifocal spectacles. Placing them in a multifocal contact lens is in many cases the ideal treatment.
As for aberration control, the more I use it, the more I appreciate it. We know that reducing the amount of positive spherical aberration can improve visual quality in varying light levels for many patients, particularly for those who have large physiological pupil diameters. Spherical aberration becomes very apparent during pupil dilation in low light conditions. So spherical aberration correction can benefit patients regardless of their photopic pupil size because we know that the pupil size increases as they move from photopic to mesopic and scotopic lighting conditions.
In my experience, vision is just as or more important than comfort during contact lens wear. For example, a keratoconus patient will tolerate all sorts of contact lens discomfort to achieve better vision. However, we should remember that great vision is just as important to all of our patients who also expect great comfort. In the end, it's not all about comfort. CLS
Dr. Hom is a member of the Bausch & Lomb Speaker's Panel. He practices in Azusa, CA.