Excimer laser procedure holds appeal in younger patients

"Considering younger [patients with] presbyopia, which would include patients aged up to ~55 years, corneal surgery of any type is preferable to intraocular surgery with IOL implantation, and among the corneabased techniques, presbyLASIK has advantages compared with corneal inlays," reported Dr Tamayo, director, Bogota Laser Refractive Institute, Bogota, Colombia.

Younger patients with presbyopia represent a large population of potential candidates for surgical presbyopia correction. However, for the most part, these individuals prefer a quick and minimally invasive procedure, even if it has to be repeated. PresbyLASIK fits those criteria and is also reversible by performing a wavefront-guided ablation. Furthermore, unlike corneal inlays, presbyLASIK allows for easy simultaneous correction of refractive errors.

Noting that he also uses corneal inlays for presbyopia correction, Dr Tamayo observed that the inlay procedures are performed in only the nondominant eye. Therefore, they result in a type of monovision. As presbyLASIK is performed as a bilateral procedure, support for near vision is derived from both eyes. Another advantage of presbyLASIK compared with inlays is that the procedure is more familiar to surgeons and patients.

"Inlay surgery has a learning curve for doctors and patients, whereas presbyLASIK involves a well-known surgery performed with a software change," he said.

Dr Tamayo acknowledged that the cornealbased presbyopia-correcting procedures, including presbyLASIK, are not perfect. One of their disadvantages is that they are only a temporary solution for the patient.

"Careful patient selection is important, but that applies to any presbyopia-correcting procedure, even contact lens monovision," he advised. Adverse visual symptoms can occur, but that, too, is a feature of other presbyopia-correcting surgeries and often symptoms improve with time.

Proof of efficacy

A presbyLASIK ablation pattern developed by Dr Tamayo produces a multifocal cornea with changes in spherical aberrations that increase depth of focus. The treatment creates positive spherical aberration in the central cornea and negative spherical aberration peripherally; distance vision is through the centre of the cornea and near vision in the periphery.

Dr Tamayo highlighted its efficacy by reporting outcomes achieved in a series of 121 eyes of 66 patients with follow-up ranging from 8 to 36 months. The patients were between 42 and 70 years of age at the time of treatment (mean 41 years), had preoperative sphere between –5 and +5 D, and up to –6.5 D of cylinder. Patients with hyperopia represented the majority of the group (58%), nearly one-third of the patients had myopia, and a small proportion (11%) had emmetropia. LASIK accounted for most of the procedures (87%), but there were some LASEK surgeries (13%) and 10% of eyes were undergoing re-treatment.

Binocular distance uncorrected visual acuity (UCVA) was 20/40 or better in 97.5% of patients, although results were better in patients with emmetropia (92% UCVA 20/25 or better) and myopia (100% UCVA 20/25 or better) than in hyperopia (66% UCVA 20/25 or better).

Similarly, binocular near UCVA was 20/25 or better in 100% of patients with myopia and emmetropia, but in only 78% of hyperopia. However, 100% of patients with hyperopia had binocular near UCVA of 20/40 or better. Distance best-corrected visual acuity was 20/20 or better in 96% of patients.

Patient survey results also supported the efficacy and safety of presbyLASIK. Overall, 93% of patients were fully spectacleindependent, 94% would repeat the surgery, and 100% said it was a big positive change. An increase in visual symptoms was reported by 19% of patients while 3.6% indicated having night-life difficulty.