In the past year, Matossian Eye Associates added a new category of presbyopia-correcting IOLs to the practice: the extended depth of focus (EDOF) IOL. The first IOL in this category is the Tecnis Symfony (Johnson & Johnson Vision). EDOF lenses from other manufacturers are in clinical trials, so it behooves the cataract surgeon to better understand how these lenses work.
Unlike the distinct single or dual foci of a monofocal or multifocal IOL, the EDOF lens has an elongated area of focus (Figure 1) that provides high-quality vision over a continuous range. This is the kind of vision that patients want from a presbyopia-correcting IOL.Matossian Eye Associates conducted a retrospective analysis of 1-month results of all EDOF lenses implanted in the first 3 months that the practice began using the Symfony lenses. The data set includes all patients–eyes implanted with all 4 toric EDOF powers, post-LASIK eyes, and some patients with mild pathology, including epiretinal membrane, corneal epitheliopathy, elevated intraocular pressure (with normal optic nerve and no history of glaucoma) and macular drusen.
Importantly, these types of eyes no longer have to be excluded from consideration for a presbyopia-correcting IOL.
A toric EDOF was implanted in over half of the cases (55%). I do not like to make large arcuate incisions, so in the past I would not have considered these patients as good candidates for a presbyopia-correcting IOL.
It is an advantage to have toric EDOF lenses, as well as toric multifocal IOLs. Of the spherical implants in this data set, nearly half of patients (44%) also had limbal relaxing incisions (LRIs) for correction of low astigmatism (<1 D).
Early clinical outcomes
The average age was 66.4 ± 7.1 years (range age 52 to 79) and 65% of the patients were female.
Target refractions ranged from +0.25 D to -0.50 D, with a slightly lower mean target for the non-dominant eyes (-0.20 D, vs. -0.03 D for the dominant eyes). In all, 64% of eyes were within 0.25 D of the intended refractive target, while 83% were within 0.50 D.
All eyes had ≤ 0.50 D of residual refractive cylinder at 1 month, with 75% of eyes having 0.0 D of residual cylinder. There was no significant difference in residual cylinder by type of IOL (sphere or toric EDOF).
The best-corrected distance visual acuity (BCDVA) at 1 month was 0.02 logMAR, or about 1 letter worse than 20/20. No eye had a BCDVA worse than 20/25, and 62.5% had a BCDVA of 20/20 or better. All but 1 eye had 20/20 best-corrected near visual acuity (BCNVA).
Mean monocular uncorrected distance visual acuity (UCDVA) was 0.15 logMAR, or between 20/25 and 20/30, with a standard deviation of 0.11 logMAR (about 1 line of vision). UCDVA was statistically significantly better (p=0.03) with the Symfony Toric IOL than with the Symfony IOL, by about 1 line (0.11 logMAR or ~20/25 vs. 0.19 logMAR or ~20/30). There was no statistically significant difference in UCDVA between the dominant and non-dominant eyes (p=0.19)Mean monocular uncorrected intermediate visual acuity (UCIVA) was 20/20 and near (UCNVA) was 20/30 (See Figure 2).
What I’ve learned
Since those initial cases, some changes have been implanted in how I plan for surgery and counsel patients.
1. Balance the refractive targets
Early cases, I targeted a slightly myopic outcome. I now aim for plano in both eyes, with the caveat of choosing the IOL power that is closest to plano on the plus side for the dominant eye and on the minus side for the non-dominant eye. In other words, if the IOL formula printout shows IOL power options that would provide either -0.09 D or +0.13 D, I would choose the latter if operating on the dominant eye and the former for the non-dominant eye.
2. Counsel adequately
It is not enough to tell patients they will have “functional near vision,” as this is not necessarily a term they recognize. I provide examples of what they probably will NOT be able to do with an EDOF lens (read a newspaper, read the back of pill bottles). I discuss the possibility of halos, starbursts, and glare, which—while much less likely than with multifocal IOLs—still may be noticeable to the discriminating patient.
3. Consider mix-and-match for myopes
Myopes may become accustomed to removing their glasses to see at near. I address this by implanting an EDOF lens in the dominant eye first; then engage the patient in the decision about whether it provides the desired near vision. If the patient would like a better near vision, I implant a low-add multifocal (typically a Tecnis Lens ZLB00 [Johnson & Johnson Vision] with a +3.25 D add). This was beneficial for a recent patient who is a physician in internal medicine. He loves the blended vision because it gives him great distance and intermediate vision, but still allows him to read EKG printouts (See Figure 3).
4. Push plus in postop refractions
Refracting a patient with an EDOF lens requires a unique approach, so it is important to work closely with technicians and co-managing optometrists to make sure the patient knows what to expect. This tuturial video can be a useful training tool.
EDOF lenses love to “gobble up minus” so surgeons should start at plano and ask the patient, “Better 1 or 2?” The patient may ask for more minus.
For a more accurate refraction, fog the patient first. Start with +1.50 D in the phoropter, then take away plus in 0.25-D steps until the patient can just read the 20/20 line.
This is the “real” refraction. My early results reflect a lower-than-actual 20/20 rate because my staff did not know to do this in early cases.
With these changes, patients are achieving excellent results with EDOF lenses.