FITTING POST RK PATIENTS WITH GP LENSES
Millions of patients have undergone refractive surgery. Radial keratotomy (RK) surgery was popular in the 1990s, and then laser-assisted in situ keratomileusis (LASIK), photorefractive keratectomy (PRK), and other variants emerged as safer, more effective options. Though many patients are satisfied with their vision, we still see many patients who have become dependent on glasses again, whether it be from presbyopia or refraction shifts.
Figure 1. Hex K is a type of refractive surgery for hyperopic patients.
As the pupil of RK and LASIK patients gets larger during ambient or nighttime conditions, they may complain about decreased vision and haloes. This is especially common in patients who have undergone Hex K, a type of RK surgery for hyperopic patients (Figure 1). Another common complaint is fluctuating vision. Practitioners and patients can attest to the fact that RK patient refractions change throughout the day. Refractive surgery patients also may complain of dry eye syndrome.
Figure 2. Topography of highly irregular cornea following radial keratotomy surgery.
Luckily, there are many options for post-refractive surgery patients. If you have a topographer, assess their corneal shape. I will often attempt a standard soft contact lens first and evaluate the vision and fit. If acceptable, such lenses can provide great vision and comfort and can save patients money. If a standard contact lens does not fit well or provides suboptimal vision, I usually recommend a custom soft, hybrid, or GP lens.
If a patient has mild-to-moderate irregularity, a soft custom or hybrid lens may be a good choice, while a moderate-to-severe irregularity may require a GP. Explain the options to patients along with their pros and cons. If a patient has a highly irregular cornea, I will recommend a GP lens right off the bat and not even offer any soft lens options (Figure 2).
Case Report
A 62-year-old white female presented to the clinic for a comprehensive eye exam. She had undergone RK surgery in both eyes in 1990. The surgery results lasted for about eight years, then her vision regressed; she had been wearing glasses ever since. Entering vision with glasses was 20/50 OD and 20/40 OS. With a new manifest refraction of +1.50 –2.25 x 076 OD and +2.00 –3.75 x 054 OS, she could achieve 20/40 acuity OD, OS, and OU. Her ocular health was relatively normal except for 10 RK scars OD and eight OS. There was 1+ nuclear sclerosis of both lenses. She had slight meibomian gland dysfunction in both eyes. The posterior segment was unremarkable.
I recommended scleral GP lenses and explained their pros and cons. After a careful diagnostic fitting, she was fit into Atlantis Scleral lenses (X-Cel Specialty Contacts) with a 7.85mm base curve and 16.5mm diameter OD and OS; 5.072 sagittal height, –3.00D, and a standard edge OD; and 5.022 sag height, –3.50D, and a flat edge OS. With these lenses, visual was 20/25 OD and 20/20 OS. After verifying the fit was appropriate, she was sent home. At her one-week follow up, her vision remained 20/25 OD and 20/20 OS. She said her vision did not fluctuate during the day anymore, and she was seeing clearer than she had in many years. This patient has been wearing scleral lenses successfully for three years now.