Unilens has an answer for your astigmatic
BY ARNOLD BIERMAN, O.D.,
As the presbyopic population increases, a greater number of these patients make their way into our offices. They complain about taking off their glasses or tilting their head to read or see a computer screen. If you've heard these complaints before, multifocal contacts could be your best option, with early and moderate presbyopes obviously the preferred candidates. When dealing with an "aging" population, it is always nice to provide a patient with a means of feeling younger, so we always suggest a contact lens trial. Our explanation is simple: "Look up, down or straight ahead and comfortably do everything you have been accustomed to over the years." No patient ever objects to this.
Many choose GPs
Although the majority of our patients select soft multifocal contact lenses, many choose gas permeables -- obviously for astigmatism, but also when very crisp distance acuity is important. Fully a third of our presbyopes have enough astigmatism to make them poor candidates for a soft multifocal contact lens.
The GP design preferred in our practice for early presbyopes (generally those requiring add power of +1.50D or less) is the Unilens RGP. When demand for near is greater or for presbyopes requiring an add up to +2.50D, we use the Unilens RGP Plus. Both are back-asphere designs that form multiple focal points on the retina and allow the brain to select a light source from any given distance. This eliminates moving the eye or head to adjust to various visual conditions.
The Unilens offers flexibility
These lenses offer several diameters and a wide range of base curves to provide all the options we require to maximize the fit. It's easy to go larger, smaller, flatter or tighter and still achieve an optimum fit. If comfort is an issue, Unilens also offers this asphere in a thin version under the QuantumThin brand. Recently, the company introduced the CV Front Aspheric Multifocal, a new design with a spherical base curve and front asphere for easier fitting and avoidance of corneal molding.
Getting a good fit
The key to fitting a GP multifocal is obtaining good centration and optimal lens movement. This is a requirement for good acuity at both distance and near. Patient selection is also very important. Look for a high level of motivation, habitual distance Rx of + 0.75D or greater and corneal astigmatism not exceeding -2.50D x 180 and -0.75D x 090. Corneal astigmatism requires a steeper lens and more minus power. Your lab will provide easy guidelines to calculate a cylinder adjustment as well as base curve selection.
An over-refraction is valid only if the lens centers well with mid-peripheral alignment and slight central pooling. Adjust distance acuity monocularly using hand-held lenses in 0.25D steps, and then recheck binocularly in 0.25 steps to 20/20. With distance over-refraction in place, check near acuity. If improvement is required, add +0.25D to the non-dominant eye. After you've worked with the lens a few times, you'll see the relative ease with which you can fit this type. We are very pleased with it. Most labs offer excellent warranty plans that allow multiple lens changes and/or cancellation of the patient without financial risk.
Expand patients' horizons
It never ceases to amaze me that so many patients aren't aware of bifocal or multifocal contact lenses, yet have heard about monovision as an alternative for early presbyopia. In our practice, we prefer to offer a full range of vision in both eyes and use monovision only as a last alternative. It's a real joy when good binocular near and distance acuity have been achieved. With presbyopia now the largest segment of your patient population, consider offering GP multifocals as an equally important alternative to soft bifocals or
DR. BIERMAN IS IN PRIVATE PRACTICE IN LANSDALE, PA.
Optometric Management, Issue: April 2003