Monovision LASIK a good option for emmetropic presbyopes
Visual symptoms may affect night driving but are generally tolerated.
In the U.S., LASIK monovision is still the most popular way to correct presbyopia in patients with a clear lens. As it is for all techniques for presbyopia, there are tradeoffs, but overall “it is a great way to go for the right patient,” according to Julie M. Schallhorn, MD.
In a study published in Clinical Ophthalmology, a retrospective review of 294 emmetropic presbyopes who underwent monovision LASIK demonstrated that the procedure leads to high patient satisfaction despite reported increased difficulty with driving at night.
Schallhorn said that emmetropia was defined in this study as good uncorrected distance vision, and some cases of mild hyperopia were therefore included.
Patients were assessed before surgery for their candidacy. Some of them were already accustomed to monovision through contact lenses. The other candidates had a monovision trial with trial frames in the clinic, and if they liked it, they were scheduled for surgery. Those who were unsure underwent a monovision trial with contact lenses at home before signing their consent to the procedure.
“When we have patients asking for presbyopia correction, we discuss with them the various options. Many patients are familiar with LASIK because they have friends who have had LASIK with good results, and it is less invasive than refractive lens exchange. However, we always make sure they experience monovision beforehand. No one should undergo this surgery if they don’t feel completely positive about the trial experience,” Schallhorn said.
The target refraction in the near eye ranged from –1 D to –2.25 D, with a mean of –1.48 D. Near acuity improved to 20/40 or better in 88.9% of the eyes as compared with 4.7% preoperatively. The final uncorrected distance visual acuity in the distant eye was 20/20 or better in 89.8% and 20/25 or better in 98.3%.
Overall satisfaction was high, with 85.4% of patients saying they were satisfied or very satisfied with their vision, 89% saying they would recommend the experience and 84% reporting improvement in their life. All patients gained increased ability to do sports and perform near activities in everyday life and hobbies.
“Monovision by and large makes people satisfied because they can perform near tasks. It does come with a decrease in stereoacuity, but a lot of people find this an acceptable tradeoff to get more near range in their vision,” Schallhorn said.
However, increased difficulty with driving was reported, particularly at night, due to increased visual symptoms such as glare, halos, starbursts and ghosting.
Several studies have previously shown that visual symptoms with LASIK are related to uncorrected sphere or cylinder.
“Obviously these patients have defocus in their near eye, and if they don’t wear spectacles, they will have visual symptoms from that. This is because they have uncorrected refractive error. But we gave them ametropia on purpose to increase their near vision, so it is a tradeoff. Most patients are able to drive well in spite of these disturbances, and those who are not can just choose to wear spectacles at night, which does the trick for most,” Schallhorn said.
No technique is perfect
Whether it is monovision LASIK, multifocal LASIK, or an IOL such as a multifocal or extended depth of focus, all techniques that correct presbyopia result in some visual symptoms. It is important to recognize that this is going to happen and discuss it with patients.
“What I say is, ‘We don’t have anything that can give you back the eyes of a 20-year-old. These are the options we have. These are the good things about them, and these are the things people report that bother them.’ I make patients aware of all this before they decide whether to have surgery. I let them think about it and decide whether or not the downsides of procedures are something they are going to be able to tolerate,” Schallhorn said.
Of the patients participating in the study, none had monovision reversal. Disturbances were limited to visual symptoms, and none of the patients experienced problems with adaptation to monovision.
It should be noted that all the patients included in the study had excellent uncorrected visual acuity preoperatively and underwent treatment with the only goal of correcting presbyopia.
“This patient cohort is one of the most demanding that a refractive surgeon will encounter in their practice, and in this study did well with good refractive results and high levels of satisfaction,” the authors wrote. – by Michela Cimberle
- Peng MY, et al. Clin Ophthalmol. 2018;doi:10.2147/OPTH.S170759.
- For more information:
- Julie M. Schallhorn, MD, can be reached at Department of Ophthalmology, University of California, San Francisco, 10 Koret Way, San Francisco, CA 94143; email: firstname.lastname@example.org.
Disclosure: Schallhorn reports she is a consultant to Zeiss and Avedro.