Various factors, including a compounded reduction in contrast sensitivity and reduced reading speed, mean that multifocal IOLs are not ideal for patients with early or subclinical AMD. It is therefore imperative to identify such patients—using a simple practice tool—and enable them to make an informed choice preoperatively.
The symptoms of age-related macular degeneration (AMD) and cataract are quite similar, with night vision difficulties being a common finding in both conditions. A standard comprehensive eye exam will usually determine which disease is driving the symptomatology in patients with intermediate to late-stage AMD.
However, it is easy to overlook early and subclinical AMD when looking only for drusen. This could put these patients who are considering a multifocal intraocular lens (IOL) at significant risk of less than optimal surgical outcomes.
Here, we discuss why patients who have early AMD may not be ideal candidates for a multifocal IOL and present a simple practice tool for identifying early disease so that patients and surgeons can make better informed choices preoperatively.
Multifocals compound risk in AMD patients
Multifocal lenses help patients see at different distances by splitting light into multiple foci. The tradeoff for visual improvement at both distance and near is an expected (but hopefully mild) reduction in contrast sensitivity. However, because macular degeneration and multifocal IOLs both reduce patients’ contrast sensitivity, one would face a compounded reduction in contrast sensitivity and perhaps decreased visual outcomes.1
Beyond contrast sensitivity, good macular function is also required to achieve normal reading speed with multifocal IOLs,1 which again should urge us to look more carefully for any signs of AMD.
1. Braga-Mele R, Chang D, Dewey S, Foster G, Henderson BA, Hill W, Hoffman R, Little B, Mamalis N, Oetting T, Serafano D, Talley-Rostov A, Vasavada A, Yoo S; ASCRS Cataract Clinical Committee. `Multifocal intraocular lenses: relative indications and contraindications for implantation. J Cataract Refract Surg. 2014 Feb;40(2):313-22.
2. Neely DC, Bray KJ, Huisingh CE, Clark ME, McGwin G Jr, Owsley C. Prevalence of Undiagnosed Age-Related Macular Degeneration in Primary Eye Care. JAMA Ophthalmol. 2017 Jun;135(6):570-575.
3. Owsley C, McGwin G Jr, Clark ME, Jackson GR, Callahan MA, Kline LB, Witherspoon CD, Curcio CA. Delayed Rod-Mediated Dark Adaptation Is a Functional Biomarker for Incident Early Age-Related Macular Degeneration. Ophthalmology. 2016 Feb;123(2):344-5.
4. Jackson GR, Scott IU, Kim IK, Quillen DA, Iannaccone A, Edwards JG. Diagnostic sensitivity and specificity of dark adaptometry for detection of age-related macular degeneration. Invest Ophthalmol Vis Sci. 2014 Mar;55(3):1427-31.
5. McKeague M, Pyfer M. Using dark adaptation time to assess macular function prior to cataract surgery. Paper presented at XXXIV Congress of the European Society of Cataract and Refractive Surgeons Free Paper Session. September 12, 2016.
6. Chakrabarti M, Chakrabarti A. IOL Selection for Patients With Age-Related Macular Degeneration. CRST Europe. Available at: https://crstodayeurope.com/articles/2015-mar/iol-selection-for-patients-.... Accessed 2/9/20.