Dysfunctional Lens Syndrome: Building Your Decision Algorithm

Jun 2, 2022
7 min read
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As a refractive cataract surgeon, as well as a refractive corneal surgeon, I am frequently confronted with a presbyopic patient who desires less dependence on glasses or contacts. In many of these patients, the question often arises when to pursue lens-based surgery rather than perform LASIK, PRK, SMILE, or a corneal inlay.

To make this decision, it is important to study and understand some of the concepts behind current approaches to lens-based surgery as well as some other newer options for treating presbyopia.

What is dysfunctional lens syndrome?

Approximately 15 years ago, Drs. Daniel S. Durrie, Jason E. Stahl, and George O. Waring IV, proposed the term dysfunctional lens syndrome (DLS) to describe the spectrum of changes in the aging crystalline lens.1 This effort was brought about in large part by the increasing number of patients in their 40s or 50s who were presenting for refractive surgery due primarily to symptoms of presbyopia.

Understanding presbyopia as a lens-based problem helps better explain the need for and selection of lens-based treatments in some patients. As the human lens ages, there are characteristic changes that have been divided by Dr. Durrie and his collaborators into the stages of DLS.2

Stages of DLS1

  • In Stage 1, which has historically been recognized as presbyopia, there is stiffening of the crystalline lens with associated loss of focusing power and difficulty with near vision. This most commonly occurs between ages 40 and 50.
  • In Stage 2, occurring most commonly in those 50 and older, there is loss of accommodation, decreased contrast sensitivity, and difficulty with night vision due to light scatter within the lens.
  • Finally, in Stage 3, occurring most frequently in those age 65 and older, there is yellowing and opacification of the lens with degraded vision and altered color perception.

Diagnosis of DLS

In order to assess the functional state of the crystalline lens, it is helpful to understand some of the current diagnostic technology available.

High contrast visual acuity, while helpful in more advanced cases of DLS, will often underestimate the real-world functioning of patients with Stage 1 or 2 changes.

Anterior segment optical coherence tomography (AS-OCT) can provide not only anatomical detail of the lens and surrounding tissues, but can also be used as an objective way to grade the density of a cataract based on automated measurements.3 This can be especially helpful in younger patients who may have early-onset opacification of the lens.

Automated reproducible lens densitometry can also be measured with Scheimpflug imaging devices and similarly used to guide treatment decisions.4

Measuring wavefront aberrometry with a ray-tracing device in eyes with changes in the crystalline lens can give an objective measurement of optical changes in a dysfunctional or cataractous lens. In eyes with even Stage 1 DLS, increasing aberrations can be seen compared to a youthful lens, while in Stage 2 these changes are invariably present.5

The type and degree of these aberrations will vary, especially with different types of cataracts, and may help explain the patient’s subjective symptoms and need for treatment despite good high contrast visual acuity.

Finally, the Ocular Scatter Index (OSI) obtained by a double-pass wavefront device, can provide an objective measure of forward light scatter within the eye. Higher degrees of light scatter can correlate with even milder observable lens changes in some patients.6

Treatment options for dysfunctional lens syndrome

For patients with early or Stage 1 DLS, there are a variety of treatment options, including of course glasses and contact lenses. Some of these patients may benefit from a pharmaceutical option, such as one of the topical miotics now being developed and commercialized for presbyopic patients.

Corneal-based procedures such as LASIK and PRK can help to create a near focus in one eye of a patient who can accept partial or full monovision, as can a pinhole aperture corneal inlay.

Often, this type of surgery can simultaneously correct other underlying ametropias such as myopia, hyperopia, or astigmatism, leaving the patient with good distance vision in one eye (typically the dominant eye).

Surgical techniques aimed at correcting or reversing the aging changes associated with presbyopia, such as laser scleral microporation, may also hold promise for those with early DLS.7

Refractive lens exchange or traditional cataract surgery are typically reserved for patients with more advanced DLS, usually Stage 2 or 3. For these patients, a wide and constantly evolving array of intraocular lens implant options are available to restore not only the clarity of vision but also a full visual range.

Monofocal lens implants, with or without astigmatic keratotomy can be used to create true or modified monovision, as can monofocal toric IOLs. This is a good option for patients who have demonstrated the ability to tolerate monovision in the past and have a preference for it.

For most patients, however, newer extended depth of focus, bifocal, trifocal, pinhole aperture, or accommodating IOLs will offer the broadest range of vision with the least visual compromise. However, each of these lens technologies will present its own unique visual and visual disturbance profile, with which the operating surgeon must be familiar.

Conclusion

The progression of DLS is a natural phenomenon and a normal part of the aging process of the eye. Patients should be educated about what to expect in terms of their vision, including difficulty with near vision, decreased vision in lower light, problems with night vision and increasing blur. The use of patient questionnaires or directed questioning of patients undergoing routine eye examinations can help elicit these symptoms for discussion and possible treatment.

Dysfunctional lens syndrome is a spectrum of changes associated with the normal aging of the human crystalline lens. Recognizing and grading these changes through the use of existing clinical modalities can facilitate the treatment of lens-based disease with lens-based solutions where appropriate.

Presbyopia need not be considered inevitable or allowed to handicap those suffering from symptoms of poor visual functioning when many excellent options exist to restore vision that has been lost.

References

  1. Durrie, D. Dysfunctional Lens Syndrome, a New Way to Educate Patients. AAO Daily. 2016, Oct. https://www.aao.org/eyenet/academy-live/detail/dysfunctional-lens-syndrome-educate-patients
  2. Waring, G. Cataract & Refractive Surgery Today Europe. 2020, March. https://crstodayeurope.com/wp-content/uploads/sites/5/2020/03/0320CRSTEuro_F_WaringGuestEd.pdf
  3. Pujari, A., & Sharma, N. The Emerging Role of Anterior Segment Optical Coherence Tomography in Cataract Surgery: Current Role and Future Perspectives. ncbi.nlm.nih. 2021, Feb 3. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7869024/
  4. Kirkwood, B., Hendicott, P., Read, S., & Pesudovs, K. Repeatability and validity of lens densitometry measured with Scheimpflug imaging. ncbi.nlm.nih. 2009, July. https://pubmed.ncbi.nlm.nih.gov/19545810/
  5. Wu, C.Z., Jin, H., Shen, Z.N., & Li, Y.J.. Wavefront aberrations and retinal image quality in different lenticular opacity types and densities. ncbi.nlm.nih 2017, Nov 10. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5681554/
  6. Artal, P., Benito, A., Pérez, G., Alcón, E., De Casas, A,. Pujol, J. & Marín, J. An Objective Scatter Index Based on Double-Pass Retinal Images of a Point Source to Classify Cataracts. ncbi.nlm.nih. 2011, Feb 4. https://www.ncbAn Objective Scatter Index Based on Double-Pass Retinal Images of a Point Source to Clarify Cataracts
  7. Linnehan, R. Laser scleral microporation may restore visual performance in presbyopic eyes. Helio. 2020, Aug 26. https://www.healio.com/news/ophthalmology/20200826/laser-scleral-microporation-may-restore-visual-performance-in-presbyopic-eyes
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About Bret L. Fisher, MD

Dr. Fisher became the Medical Director of the newly created Eye Center of North Florida in 2000 and has held that position, as well as the position of Medical Director of The Laser and Surgery Center, the free-standing ambulatory surgery …

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