Ocular pathology, visual demands, and lens optics all play a role in choosing the best IOL for each patient.
Special to Ophthalmology Times®
A good refractive cataract surgery outcome starts long before an IOL is implanted. In our practice, we focus on educating patients about their options and understanding their priorities as a first step.
The education process includes videos, brochures, and questionnaires. It is important for the surgeon to feel comfortable talking about choices without overpromising or feeling like he or she is “selling” something.
A good exam to rule out poor candidates for refractive cataract surgery—those with corneal or retinal pathology or unresolved dry eye—is also essential. I look closely at placido-disc topography, optical coherence tomography (OCT), tear break-up time (TBUT), the lid margins and periocular skin, and patient reports of preoperative dryness, irritation, or fluctuating vision.
I am careful to rule out any corneal dystrophies, retinal pathology, or other conditions that might affect vision. I want to make sure the patient’s ocular anatomy truly supports spectacle independence before an advanced-technology lens is recommended.
Ocular surface disease (OSD) doesn’t necessarily rule out a candidate for advanced-technology lenses, but it must be addressed. In mild cases, we may only prescribe artificial tears and move forward with scheduling surgery.
However, if there is significant OSD with central punctate staining or irregular topography, I would want to start the patient on a regimen to improve the ocular surface and then bring that patient back for additional testing before selecting the IOL. Otherwise, dry-eye induced abnormalities may lead us to choose an incorrect power, axis, or even lens type (toric when not needed or vice versa).
If a patient is a candidate for a presbyopia-correcting IOL and is interested in greater spectacle independence, then we’ll test ocular dominance.
My preference is almost always to put an extended-depth-of-focus (EDOF) lens (Tecnis Symfony, Johnson & Johnson Vision) in the distance-dominant eye because this lens meets all my requirements for the highest possible optical quality.
Here are the factors that have gone into that decision:
Correction of spherical aberration (SA) to nearly zero.
SA occurs when incoming light rays are focused on different points on the retina (Figure 1). It affects the resolution and clarity of images, making it hard to obtain sharp edge contrast, especially in dim light.
There are situations, such as a post-hyperopic-LASIK patient, where we want to leave the total SA unchanged or avoid inducing more negative SA. But in most eyes, a -0.27 µm negative SA lens that reduces total SA close to zero is desirable.
Dr. Silvera specializes in cornea, cataract and refractive surgery at the Talley Eye Institute in Evansville, Ind. He has received speaking fees from Johnson & Johnson Vision. Contact him at [email protected]
1. Kontos MA. Analysis of Patient Satisfaction, Visual, and Functional Outcomes After Bilateral vs. Paired Extended Range of Vision / +3.25 D Multifocal IOL Implantation. Presented at ASCRS, May 5, 2019.
2. Solomon KD. Outcomes Post-Implantation of an Extended-Depth-of-Focus Intraocular Lens When Combined with a Multifocal +3.25 D Add Intraocular Lens. Presented at ASCRS, May 5, 2019.