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Monovision via LASIK or inlay: A presbyopia debate
Contact lens trials can be used to predict patient response with either technology, but which is better?
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Welcome to another edition of CEDARS/ASPENS Debates. CEDARS/ASPENS is a joint society of cornea, cataract and refractive surgery specialists, here to discuss some of the latest hot topics in ophthalmology.
Dealing with presbyopia in our refractive surgery patients continues to be a challenge. Monovision with LASIK has been used for years. More recently, corneal inlays have become available. It may be difficult to tell which procedure will be better tolerated and preferable to the patient.
This month, Sumitra Khandelwal, MD, and Priyanka Sood, MD, discuss their approaches to managing these patients.
We hope you enjoy the discussion.
Kenneth A. Beckman, MD, FACS
OSN CEDARS/ASPENS Debates Editor
Sumitra Khandelwal, MD: Not all patients adapt to monovision, but one big advantage of monovision LASIK is the ability to perform a contact lens trial before surgery, something that cannot be done with corneal inlays. Monovision depends on interocular blur suppression. There is an assumption that it is easier to suppress blur in the nondominant eye, but this is not always true.
Priyanka Sood, MD: A multifocal contact lens trial in the nondominant eye has been used to mimic the outcome of corneal inlays as well, and it can offer a fair representation of what monovision would be like with inlays.
Khandelwal: In addition, using contact lens trials once can maximize the near vision potential by balancing the desire for near vision with the stereopsis. With inlays, on the other hand, there is limited range of near vision. Therefore, if patients requiring inlays need to tolerate monovision, it is best to do the surgery that has the most predictive outcome.
Sood: Depending on the age of the patient, the amount of monovision treated will vary. Making a 45-year-old a –2.00 is not sensible; however, with the inlay, maintaining the distance vision makes this less of a concern. Repeat treatments with LASIK for progressive presbyopia are possible but not without risk.
Khandelwal: Visual recovery is quicker with LASIK than with inlays, in that vision is decreased in the first 1 to 3 months following inlay implantation due to ocular surface issues and cornea wound healing. Neuroadaptation for monovision can take up to 6 months.
Risks associated with LASIK and PRK are well known, and complications are rare. Inlays have had reported decreases in distance corrected vision and issues with haze and explantation.
Sood: Treatment with mitomycin C as a means of reducing or preventing haze in patients implanted with corneal inlays has been seen as promising, although more research is needed.
Khandelwal: New excimer lasers will allow for patients to be candidates for premium lens surgery later. Inlays may cause haze, resulting in topographic and cornea changes that would prohibit later premium lens surgery.
Sood: If patients are happy with their vision, then there is no need for a premium lens. Theoretically, a premium lens could be considered in the dominant eye to enhance the near vision and maintain stereopsis, but it is not necessary if the patient is happy with the inlay.
Khandelwal: Incidence of dry eye is likely higher in patients with inlays, although no study has compared the two. When the surgeon implants a corneal inlay, he or she first develops a flap or pocket, as would be done for LASIK, but then the placement of the inlay acts as a foreign body, necessitating epithelial remodeling.
Sood: The ocular surface should be optimized before LASIK as well as inlay surgery because dry eye is a consideration in either surgery and longer recovery time is part of the process. Neuroadaptation with the Kamra inlay (CorneaGen) can take many months.
Khandelwal: A study by Verdoorn showed that one advantage of inlays may be in better binocular stereopsis; however, any issues with monovision such as night vision or depth perception can be corrected with “balance” glasses. For either option, patients need proper counseling and should be told that the ability to read without ever needing correction is not guaranteed. The risks associated with inlays, including haze and need for explant, far exceed the need for balance glasses for monovision LASIK.
Sood: The same study concluded that inlay patients were happier with their visual function than monovision patients. Furthermore, active patients are interested in maintaining stereopsis for various athletic activities. The patients in whom I had implanted inlays were not interested in losing depth perception for all activities, not just for driving at night. They were interested in being as glasses-independent as possible.
Khandelwal: Myopic patients achieve excellent results with monovision LASIK. Patients with hyperopia may be better candidates for refractive lens exchange regardless but could tolerate low hyperopic corrections that may regress. Emmetropic presbyopic patients may be the least satisfied, so counseling is important for any surgery, including inlays, lens exchange and corneal excimer surgery.
Sood: Another advantage of corneal inlays is that they are additive and do not actually remove any tissue, which preserves the capacity for reversal/removal or future options of any other type of presbyopia correction.
Finally, an aspect of medicine that I find interesting is that a technology can be developed that has great potential, but without sufficient funding to grow it in the market, it can ultimately fail. In February 2018, ReVision Optics announced that it would be shutting its doors. The inlay technology was performing as expected, and many patients were satisfied with the outcome; however, the company could not financially sustain the effort to obtain full adoption.
- References:
- Kim J, et al. Br J Ophthalmol. 2015;doi:10.1136/bjophthalmol-2014-305449.
- Lindstrom RL, et al. Curr Opin Ophthalmol. 2013;doi:10.1097/ICU.0b013e328362293e.
- Peng MY, et al. Clin Ophthalmol. 2018;doi:10.2147/OPTH.S170759.
- Schallhorn SC, et al. J Refract Surg. 2017;doi:10.3928/1081597X-20170721-03.
- Verdoorn C. Clin Ophthalmol. 2017;doi:10.2147/OPTH.S142075.
- Whitman J, et al. Ophthalmology. 2016;doi:10.1016/j.ophtha.2015.11.011.
- For more information:
- Sumitra S. Khandelwal, MD, can be reached at Baylor College of Medicine, 1977 Butler Blvd., 2nd Floor, Houston, TX 77030; email: sumitra.khandelwal@bcm.edu.
- Priyanka Sood, MD, can be reached at Emory Eye Center, 1365 Clifton Road, Atlanta, GA 30324; email: psood2@emory.edu.
Disclosures: Khandelwal reports relevant financial interest with Alcon and Zeiss. Sood reports no relevant financial disclosures.