Surgical presbyopia treatment methods

Surgical presbyopia treatment methods

Presbyopia is a natural result of the aging process. Over time, the crystalline lens of the human eye increases in volume and becomes less flexible, which reduces its accommodation ability. Presbyopia affects most people aged 45 or older, though the accommodation amplitude decreases continuously with aging. Presbyopic symptoms appear earlier in individuals with hyperopia than in those with myopia, and in women. According to estimates, in 2015 there were 1.8 billion patients with presbyopia globally, including 826 million patients with impaired near vision due to not using corrective eyeglasses or using inadequate corrective glasses [11]. ] As the global population continues to grow, the problem is expected to affect 2.1 billion people by the year 2030. The prevalence of presbyopia is greater in developed countries owing to longer life expectancy. Conversely, impaired vision due to uncorrected presbyopia is the most common in developing countries, where as many as two-thirds of patients may use no correction for a variety of reasons, including financial and psychological ones.

In the normal accommodation process, the pupil constricts, and the optical power of the lens increases thanks to increased curvature of its front and back surfaces. The von Helmholtz theory states that during accommodation, the circular contraction of the ciliary muscle and its forward movement reduce the tension of zonular fibers, allowing the lens to increase its curvature. According to the Schachar theory, the contraction of the ciliary muscle during accommodation causes selectively increased tension of the equatorial zonule fibers, resulting in a movement of the equator of the lens towards the sclera. The direct tensing of the zonular fibers would increase the curvature of the lens, as opposed to the passive effect proposed by Helmholtz. According to this theory, the age-related deterioration of accommodative ability results from a slight increase of lens volume and diameter, reduction of the distance between the lens and the ciliary body, and lower tension of zonular fibers.

Corrective eyeglasses are the most used method of presbyopia treatment. The large prevalence of presbyopia requires solutions that would help patients regain accommodation and not rely on eyeglasses. Techniques for surgical presbyopia correction are undergoing intense development. Table 1 shows a comparison of surgical treatments for presbyopia.

Table 1. Surgical presbyopia treatment methods

Targeting the lens Targeting the cornea Other/novel methods
– monovision
– accommodating (experimental)
– piggyback
– with a pinhole diaphragm
– bifocal
– trifocal
– EDOF
– phakic lenses
– PresbyLASIK
– Presbyond
– Intracor
– Inlays 
– scleral buckling
– light-adjustable IOL (LAL)
– PEARL 

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Monovision is a cheap presbyopia treatment method, and is the most commonly used, both in refractive surgery and in cataract surgery. It involves the deliberate creation of anisometropia, or unequal optical power, so that one eye is corrected for distance, and the other — for near vision. The natural configuration, with the dominant eye set for distance vision and the non-dominant eye for near vision, is most commonly used. [2Alternatively, crossed monovision may be used, with the non-dominant eye corrected for distance and the dominant eye corrected for near vision. This configuration is not physiological, however, and so it is less commonly used. [3] Historically, monovision involved establishing anisometropia of more than 2 diopters (D), but the technique is no longer widely used due to problems with the perceived size of images from each eye (aniseikonia) and loss of stereopsis, i.e. depth perception. [4] With mini-monovision, resulting in anisometropia of 1.0–1.5 D, or micro-monovision (anisometropia below 1 D), stereopsis is affected to a much lesser extent. Thus, the methods are well tolerated by the vast majority of patients. (2] Micro- and mini-monovision do not allow for dispensing with reading glasses altogether, but limit the need to use them, e.g. just to reading very small print. The technique well tolerated by approx. 60–70% of patients. Monovision can be achieved using contact lenses, refractive corneal surgery, or intraocular lenses (IOL). In the latter case, it is cheap, as it does not require any added expense beyond that of a standard cataract surgery, and so the cost can be fully covered by the Polish National Health Fund. In any case, monovision can first be simulated using contact lenses to make sure the patient is going to be satisfied with the results after the proposed surgery.

In refractive corneal surgery procedures, presbyopia can be corrected by micro- or mini-monovision, formation of zones with different optical powers, or depth of focus extension. The term presbyLASIK, coined more than 20 years ago, refers to a surgical technique using an excimer laser to form the surface of the cornea into a multifocal structure. Multifocal ablation for presbyopia correction can be broken down by profile — with the central part used for distance vision (peripheral presbyLASIK) or for near vision (central presbyLASIK). Peripheral presbyLASIK is used much less commonly, and is only offered by the Nidek company as a “pseudoaccommodative cornea” technique. Central presbyLASIK Central presbyLASIK is performed using lasers from AMO (Visx hyperopia-presbyopia multifocal approach), Schwind (PresbyMax) and Bausch+Lomb Technolas (Supracor). Moreover, the Laser Blended Vision technique involves monovision of 1.5 D and depth of focus extension through induced spherical aberration. Importantly, presbyopia correction can be performed in deep and superficial corneal procedures. The Presbyond Laser Blended Vision method uses monovision. [5] An alternative method is Intracor, where a femtosecond laser is used to make concentric corneal incisions, changing the curvature of the central portion of the cornea.

Experimental techniques

An alternative to procedures changing the shape of the cornea involves the use of intracorneal inlays (implants). Inlays are typically inserted into a pocket cut in the cornea of the non-dominant eye using a femtosecond laser. The implant modifies the shape of the cornea (Raindrop Near Vision Inlay – ReVision Optics) and may have optical properties as well (Flexivue Microlens — Presbia, Icolens — Neoptics). [6] The Acufocus Kamra Inlay extends the depth of focus by incorporating the pinhole effect. Recently, an approach using a lenticule allograft has also been proposed. [7] Such a graft placed in the non-dominant eye improves near visual acuity by 3–5 lines.

Presbyopia correction can be combined with a surgical procedure to treat cataracts. Different types of lenses can be used in such a procedure: monofocal, bifocal, trifocal, and multifocal refractive or diffractive lenses, including extended depth of focus (EDOF) lenses. extended depth-of-focus). Refractive lenses comprise concentric rings with different powers, causing refraction of light in accordance with Snell’s law. The function of refractive lenses depends on pupil size and centration, though by increasing the number of rings, dependence on the pupil can be reduced. The construction of diffractive lenses is based on light interference. These lenses work independently of pupil size. They correct chromatic aberrations, providing better near vision without impairing distance vision. Table 2 lists types of multifocal lenses.Though the problem of dysphotopsias, i.e. glare and halo-type symptoms appearing under scotopic (low-light) conditions, is often discussed with regard to multifocal lenses, these symptoms rarely reduce patient satisfaction with the procedure in practice. With multifocal lenses, it is important to consider neuroadaptation — the process whereby the cerebral cortex adapts to new optical conditions. On the one hand, neuroadaptation is a challenge, as it requires time, but on the other, it allows most patients to mentally adapt to their new condition of multifocality.8]

When evaluating treatment outcomes in patients with multifocal lenses, a great number of parameters must be considered. Traditionally, ophthalmology uses measures such as uncorrected and corrected near, intermediate, and distance visual acuity, refractive error, and contrast sensitivity. Still, two patients with the same results of these measurements may judge their quality of vision differently. This is why subjective patient-reported outcomes (PRO) are increasingly used. PRO questionnaires assess reliance on eyeglasses, visual function over a wide range of distances and conditions, and overall satisfaction with treatment, considering the patient’s preoperative expectations. A Cochrane meta-analysis has shown that patients with multifocal intraocular lenses are more likely to be independent from glasses and have better near visual acuity than those implanted with monofocal lenses. [9Independence from glasses is reported in 38.4–86% of patients with multifocal lenses, and 9.8–32% of monovision patients.10,11Though patient satisfaction depends on quality of vision, dependence on glasses, and any visual abnormalities, their personality traits may also affect the level of discomfort experienced due to dysphotopsias.12] Individuals with a perfectionist personality, who tend to double-check things and who are extremely organized or conscientious tend to report more discomfort associated with glare or halos.

Table 2. Multifocal IOL classification

Lens designEDOF lensesMultifocal lenses
bifocaltrifocal
refractive Lentis Comfort, Mplus, MplusX
WIOL-CF
Sifi MiniWell
defractiveTecnis SymfonyAlcon PanOptix
Zeiss LISAZeiss LISA tri
pinholeAcufocus IC8

Researchers are now working on accommodating lenses based on changes in distance between the lens and retina or in the curvature of the lens, as well as variable focus lenses with dual optics. If the IOL is implanted into the lens capsule, capsular fibrosis and posterior capsule opacification may occur in the late postoperative period. Very good outcomes have been achieved with the implantation of AkkoLens Lumina accommodating IOLs with dual optics into the ciliary sulcus during cataract surgery.13 In a group of 61 patients implanted with this lens, mean accommodation of 0.63–1.27 Dsph was achieved after stimulation with an accommodative stimulus between 2.0 and 4.0 D.

Refractive lens exchange (RLE) procedures are increasingly common worldwide RLE – refractive lens exchangeBy definition, patients undergoing RLE have an unopacified crystalline lens and no cataract, and may have an altered eye anatomy (shorter eyeball in the case of hyperopia and longer eyeball in the case of myopia).14Presbyopia and achieving independence from eyeglasses can also be important indications for RLE. In presbyopic lens exchange (PRELEX)the only objective is to correct for the lost accommodation.15One advantage of RLE is the ability to correct more severe refraction errors than in traditional corneal refractive surgery. While complications in modern lens replacement surgery are very rare (approx. 1–2%), all risks are the same as for intraocular procedures. According to estimates, as many as 10% of lens removal procedures in the USA may be performed as part of refractive surgery.

Lens implantation without removal of the patient’s own lens offers an alternative to the above approaches. [16] Such phakic lenses are implanted into the anterior or posterior chamber of the eye. A phakic IOL for presbyopia may be indicated especially in younger patients with presbyopia and a large degree of myopia or hyperopia. Advantages of this method include its reversibility and a greater range of refractive error correction compared to corneal refractive surgery. Potential drawbacks include dysphotopsias, reduced contrast sensitivity, and complications typical for anterior and posterior chamber monofocal phakic IOLs. 

Summary

  1. Each patient with presbyopia should be offered a solution for reading and near vision that is suited to their activity patterns.
  2. The least invasive techniques ought to be offered first — eyeglasses with progressive lenses and multifocal contact lenses.
  3. Surgical methods should be reserved for patients scheduled for a surgical procedure (e.g. cataract surgery) or unable to tolerate less invasive solutions (listed above), who understand the risks involved in surgical intervention.
  4. Modern corneal and lens surgery is very precise. Complications are very rare (approx. 1–2%) and typically do not affect visual acuity in the long term.
  5. Patient satisfaction after surgical presbyopia treatment is affected by their understanding of the limitations of currently available solutions more than by any surgical complications.
  6. Patients should be offered specific types of surgical presbyopia treatments based on a detailed understanding of their individual visual needs (their profession, pastimes etc.), and provided comprehensive information on the ways in which each solution works.

Literature

  1. Fricke TR, Tahhan N, Resnikoff S, et al. Global Prevalence of Presbyopia and Vision Impairment from Uncorrected Presbyopia: Systematic Review, Meta-analysis, and Modelling. Ophthalmology. May 2018. doi:10.1016/j.ophtha.2018.04.013
  2. Finkelman YM, Ng JQ, Barrett GD. Patient satisfaction and visual function after pseudophakic monovision. J Cataract Refract Surg. 2009;35(6):998-1002.
  3. Zhang F, Sugar A, Arbisser L, Jacobsen G, Artico J. Crossed versus conventional pseudophakic monovision: Patient satisfaction, visual function, and spectacle independence. J Cataract Refract Surg. 2015;41(9):1845-1854.
  4. Hayashi K, Yoshida M, Manabe S-I, Hayashi H. Optimal amount of anisometropia for pseudophakic monovision. J Refract Surg. 2011;27(5):332-338.
  5. Luft N, Siedlecki J, Sekundo W, et al. Small incision lenticule extraction (SMILE) monovision for presbyopia correction. Eur J Ophthalmol. 2018;28(3):287-293.
  6. Lindstrom RL, Macrae SM, Pepose JS, Hoopes PC Sr. Corneal inlays for presbyopia correction. Curr Opin Ophthalmol. 2013;24(4):281-287.
  7. Jacob S, Kumar DA, Agarwal A, Agarwal A, Aravind R, Saijimol AI. Preliminary Evidence of Successful Near Vision Enhancement With a New Technique: PrEsbyopic Allogenic Refractive Lenticule (PEARL) Corneal Inlay Using a SMILE Lenticule. J Refract Surg. 2017;33(4):224-229.
  8. Alió JL, Pikkel J. Multifocal Intraocular Lenses: Neuroadaptation. In: Alió JL, Pikkel J, eds. 
  9. de Silva SR, Evans JR, Kirthi V, Ziaei M, Leyland M. Multifocal versus monofocal intraocular lenses after cataract extraction. In: Cochrane Database of Systematic Reviews DOI: 10.1002/14651858.CD003169.pub4. ; 2016.
  10. Gimbel HV, Sanders DR, Raanan MG. Visual and refractive results of multifocal intraocular lenses. Ophthalmology. 1991;98(6):881-887; discussion 888.
  11. Javitt JC, Wang F, Trentacost DJ, Rowe M, Tarantino N. Outcomes of cataract extraction with multifocal intraocular lens implantation: functional status and quality of life. Ophthalmology. 1997;104(4):589-599.
  12. Mester U, Vaterrodt T, Goes F, et al. Impact of personality characteristics on patient satisfaction after multifocal intraocular lens implantation: results from the “happy patient study.” J Refract Surg. 2014;30(10):674-678.
  13. Alio JL, Simonov A, Plaza-Puche AB, et al. Visual Outcomes and Accommodative Response of the Lumina Accommodative Intraocular Lens. Am J Ophthalmol. 2016;164:37-48.
  14. Alio JL, Grzybowski A, El Aswad A, Romaniuk D. Refractive lens exchange. Surv Ophthalmol. 2014;59(6):579-598.
  15. Grzybowski A, Kanclerz P. Problems With Different Meanings and Types of Refractive Lens Exchange. J Refract Surg. 2018;34(7):498-499.
  16. Pineda R 2nd, Chauhan T. Phakic Intraocular Lenses and their Special Indications. J Ophthalmic Vis Res. 2016;11(4):422-428.

Polish “Presbyopia 21” Club section

The Polish “Presbyopia 21” Club was established in April 2016 in Poznań, Poland, by Professor Andrzej Grzybowski. The creation of this first-ever Polish group of experts on presbyopia was motivated by the ophthalmologic community’s virtually unanimous view that access to reliable knowledge on modern presbyopia correction methods was insufficient.

The club brings together Polish and international ophthalmology practitioners and professors interested in modern methods for presbyopia correction.

Foundation for Supporting the Development of Ophthalmology (Ophthalmology 21)

Adam Mickiewicz Street 24/3b
60-836 Poznań
Greater Poland Voivodeship
NIP: 7811880464

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