PRESBYOPIA IS A PART OF LIFE. If we live long enough, we will experience the visual change. It is estimated that approximately 128 million Americans between the ages of 40 and 70 are currently experiencing presbyopia. Only about 70% of these patients wear some sort of vision correction.¹ But this isn’t your mother’s presbyopia. Visual demands and life demands are continuing to change. Life expectancy is increasing, people are working longer, screen time is part of most of our days, and people are continuing to be more physically active later in life.

Underlying Principles and Changes

Visual changes related to presbyopia start around age 40 and continue to progress until we are in our mid-60s, or our cataracts are considered visually significant enough for surgery. The human crystalline lens undergoes post-translational modifications, which result in degradation, and backbone cleavage, which alters the protein structure, allowing for intermolecular disulfide bonding that exposes the hydrophobic core and leads to aggregation, insolubility, lens stiffening, and cataracts.^2,3 Additionally the human lens continues to grow throughout life, which has also been suggested to be a factor in developing presbyopia.⁴

Loss of accommodation is also caused by the increase in tension of the equatorial zonules. One study found a decrease in zonular elasticity of 20% from onset of presbyopia to late presbyopia.⁵

The Journey

Presbyopia is a continuum of progression, and as such, we should be prepared to discuss the journey and its stages, as well as offer different treatment options at each turn. An alternative term to educate patients about this progression from presbyopia to cataracts is dysfunctional lens syndrome. This syndrome breaks down presbyopia into 3 stages.⁶

Stage 1 patients are our 42 to 50 year old patients in whom the lens has begun to stiffen. Loss of near vision and accommodation begin, with light scatter and higher order aberrations (HOAs) remaining relatively limited. These are our early or emerging presbyopia patients. Options for these patients include more traditional treatments, such as glasses and contact lenses. Within contact lens options exist best corrected distance vision with readers, monovision, and multifocal contacts, depending on the patient.

In addition, these patients, depending on refractive error, would be considered ideal candidates for topical presbyopia drops. This could also be used in combination with contact lenses in patients who would prefer to wear distance correction only, or in patients who are poor candidates for multifocal or monovision but still want the option to be free of using readers.

Further, these patients can be considered for 3 potential surgical options: corneal refractive surgery, intraocular contact lens (ICL) implantation, and less often, refractive lens exchange (RLE). Refractive surgeries, such as LASIK, penetrating refractive keratoplasty, or small-incision lenticule extraction, could offer the option of either monovision or blended vision for these patients. Similarly, implantation of an ICL would be performed using monovision or blended vision to help aid in near vision.

For patients in this stage, while RLE is an option, it may not be the best option since they will completely lose any remaining accommodation. Patients who are high hyperope may adapt better to this option since they tend to note the effects of presbyopia earlier.³

Stage 2 patients, who are over 50 years old, exhibit further loss of accommodation, and worsening of light scatter and HOAs, with vision degradation. At this time, night vision begins to worsen, as does contrast sensitivity. For treatment of these patients, all of the options previously discussed still exist.

Presbyopia drops, as they exist now, may be helpful in some of these patients, depending on pupil size, visual demand, and motivation. With the FDA approval of other presbyopia drops, we may find that some work better for these patients than others. Typically, these patients are further in the journey, with an increase In yellowing and stiffening of the crystalline lens. RLE is a better option in these patients than ICL or corneal refractive surgery.

Stage 3 patients are 65 years old or older and have developed a full cataract with yellowing of the lens nucleus to the point of poor visual quality and degraded vision. At this time in the journey, a visually significant cataract is defined, and surgery is needed to improve vision. Depending on the lens chosen—and many premium enhanced depth of vision and multifocal lenses exist—the options of glasses, contacts, and presbyopia drops still exist.

Discussing With Patients

Start the discussion regarding presbyopia and the journey early. Patients appreciate information and knowledge about what to expect. It is even more important for new patients who have never needed vision correction but have already begun to exhibit presbyopia changes. Take the extra time to let them know that, as the lens changes, so will the vision, until eventually a cataract will form, requiring surgical intervention. The more we normalize the journey, the easier it will be for our patients to accept and be open to vision correction options. ■

References

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. 2018;125(10):1492–1499. doi: 10.1016/j.ophtha.2018.04.013
2. Hanson SR, Hasan A, Smith DL, Smith JB. The major in vivo modifications of the human water-insoluble lens crystallins are disulfide bonds, deamidation, methionine oxidation and backbone cleavage. Exp. Eye Res. 2000;71(2):195-207.
3. Dysfunctional lens syndrome, a new way to educate patients. American Academy of Ophthalmology website. October 14, 2016. Accessed November 15, 2022. https://www.aao.org/eyenet/academy-live/detail/dysfunctional-lens-syndrome-educate-patients
4. Glasser A, Campbell MC. Biometric, optical and physical changes in the isolated human crystalline lens with age in relation to presbyopia. Vision Res. 1999;39(11):1991-2015.
5. Michael R, Mikielewicz M, Gordillo C, Montenegro GA, Cortés LP, Barraquer RI. Elastic properties of human lens zonules as a function of age in presbyopes. Invest Ophthalmol Vis Sci. 2012;53(10):6109-6114.
6. Fernández J, Rodríguez-Vallejo M, Martínez J, Tauste A, Piñero DP. From presbyopia to cataracts: a critical review on dysfunctional lens syndrome. J Ophthalmol. 2018;2018:4318405.

Dr. Koetting practices at the MD/OD practice Hines Sight in Denver, CO. Her primary focus is in anterior segment and ocular surface disease, neuro-optometry, and perioperative care. She lectures locally, nationally, and internationally, and has written for multiple publications.