prescribing for presbyopia
Fitting Emmetropic Presbyopes
Many practitioners shy away from fitting emmetropic presbyopes, most of whom have never before needed visual correction and have difficulty accepting near correction because it can blur their exceptional distance vision. Although this patient population can prove difficult to fit, doing so can grow your contact lens practice because 25 percent of patients age 40 or older who need correction are emmetropic presbyopes.
Start by listening to your patients' needs. Explore their motivation for contact lenses, as well as their occupational and hobby-related visual needs. This strategy will help you select the correct modality of correction.
A Tale of Three Patients
Following are three cases of emmetropic presbyopes and the approaches you can take for each.
Patient A is a 47-year-old female non-lens wearer whose habitual correction was +1.00 OU reading glasses. Her manifest refraction is OD plano 20/20 add +1.75, OS plano 20/20 add +1.75. She hates her spectacles and complains about needing to put them on and losing them when she takes them off.
Monovision could work for this patient. Start with no lens on the dominant eye and a lower power lens on the non-dominant eye (+1.25D or +1.50D) for near. After adaptation, increase the power of the nondominant eye for better near vision.
You could also use a simultaneous vision multifocal lens such as Bausch & Lomb's SofLens 66 Multifocal or Unilens Corp.'s C-Vue 55 Multifocal OU with plano distance power and a lower add. This doesn't blur the distance and offers improved mid-range and near vision. You could achieve a similar effect using CooperVision's Frequency 55 Multifocal in plano OU and +1.50D add using two D lenses. Later, consider increasing the reading prescription by fitting a plano +1.50D D lens on the nondominant eye and a plano +1.50D N lens on the dominant eye.
Patient B is a 62-year-old male non-lens wearer whose habitual correction was +2.00 OU reading glasses. His manifest refraction is OD +1.50 20/20 add +2.50, OS +1.50 20/20 add +2.50. His chief complaints are that he can't see golf balls anymore and that when he wears his reading glasses and looks up, some distance objects are more in focus. He doesn't want to wear glasses full time and especially not for driving.
For this patient, the slam dunk approach is to push plus OU with single vision lenses. If you push at least +0.50D OU, then he achieves 20/25+ with great intermediate vision and a great improvement overall. He keeps the +2.00 readers to use over his lenses, and he's back in his vision "comfort zone." His final prescription was +2.00 sphere OU.
Patient C is a 52-year-old female non-lens wearer whose habitual correction is full-time progressive addition lenses. Her manifest refraction is OD –0.50 sphere 20/20 add +2.00, OS –0.75 sphere 20/20 add +2.00. She's acutely aware of both distance and near vision quality.
My initial approach is a simultaneous vision multifocal lens. Assuming that the right eye is the dominant eye, apply diagnostic lenses of –0.50D with "low" add OD and –1.00D with "high" add OS. If distance vision is uncompromised and near vision isn't adequate, then try –0.75D with "high" add OD and –1.00D with "high" add OS.
Another option is a modified bifocal approach. If distance vision is most critical, then use a right single vision distance lens with a left simultaneous multifocal. Conversely, if near vision is most critical, use a simultaneous vision multifocal OD and a spherical near lens OS.
Dr. Stiegemeier is in private practice in Beachwood, Ohio. She lectures throughout the country on the subject of contact lenses and performs clinical research.