Patient selection is the key factor in obtaining the best visual outcomes after cataract surgery and intraocular lens implantation.
By Lynda Charters;Reviewed by Rosa Braga-Mele, MD, FRCSC
When choosing intraocular lenses (IOLs), patient expectations and patient selection are the primary components in achieving satisfactory visual outcomes after cataract surgery.
Because of advances in IOL technology and cataract surgery, patients are more demanding regarding the visual outcomes. However, those expectations should be handled during discussions with the patient regarding their ocular status and the type of IOL (i.e., standard or premium IOL) that best satisfies their visual needs.
Rosa Braga-Mele, MD, FRCSC, addressed the important considerations when discussing potential IOL implantation with her patients. Dr. Braga-Mele is professor of ophthalmology, University of Toronto; director of cataract surgery, Kensington Eye Institute; and director of professionalism and bio-medical ethics, Department of Ophthalmology, University of Toronto, Toronto.
When deciding if a particular patient and an IOL are a good fit, the surgeon needs to consider the patient’s personality. First, surgeons should engage with the patient to determine his or her expectations and how much less-than-perfect vision might be tolerable and the patient’s willingness to compromise.
Ocular health is a primary consideration for IOL candidates because of the impact the presence of retinal, corneal, or the ocular structure might have on IOLs. Are there patients for whom a multifocal or extended-depth-of-focus (EDOF) IOL might be contraindicated? Dr. Braga-Mele asked.
Surgeons should be alert to the presence of pseudoexfoliation; trauma; small atonic pupils; advanced glaucoma; corneal pathologies, such as epithelial basement membrane dystrophy (EBMD), dry eye disease, Fuchs’ dystrophy, astigmatism, and keratoconus; and retinal diseases, such as age-related macular degeneration and diabetic macular edema.
Cataract surgery and dry eye: Ocular surface must be optimized pre-operatively for accurate keratometry. (Images courtesy of Rosa Braga-Mele, MD)
Surgeons also should ask about any previous refractive surgeries that patients might have undergone.
Regarding dry eye and EBMD, Dr. Braga-Mele emphasized the importance of irregular results on testing, differing K values on different tests, irregular astigmatism, the results of Rose Bengal and lissamine green staining, tear osmolarity exceeding 316 mOsm/L, and topography results, including Placido disc, scanning slit or Scheimpflug photography.
She explained that for patients with dry eye undergoing cataract surgery, optimization of the ocular surface is important preoperatively to ensure accurate keratometric measurements, with the goal of therapy being stabilization of interblink tear film.
“Topography results that show ‘hot spots’ and ‘flat spots’ are considered abnormal, as are irregularly shaped or smudgy Placido discs,” Dr. Braga-Mele said. She advised surgeons to look closer if the average K values are different or if the K values all differ.
Goal of dry eye therapy prior to cataract surgery is to stabilize interblink tear film.
Dry eye management with cataracts
Timing is everything, and that applies to cataract surgery planning. Patients should be tested for dry eye well before surgery because dry eye can affect topography or the results obtained with the IOLMaster (Carl Zeiss Meditec), Dr. Braga-Mele pointed out.
“Consistent readings are needed,” Dr. Braga-Mele added. “Treatment should begin at least two weeks before testing for cataract surgery, depending on the severity of the dry eye or until two consistent readings are obtained.”
Importantly, both cataract surgery and femtosecond laser cataract surgery can worsen dry eye.
Lifestyle factors are important when choosing the proper IOL. “Find out what patients value most in vision–i.e., distance, intermediate, near–and determine the ocular dominance with plano the goal,” Dr. Braga-Mele explained. “Surgeons need to discuss astigmatism and the impact it has on vision postoperatively. Is the patient using monovision or multifocal contact lenses? Of utmost importance are the work and play activities that patients engage in and their visual needs in relation to them.”
Detailed communications between the patient and surgeon must occur to discuss all potential visual outcomes, which include informing the patient about the postoperative presence of glare and/or halo with some multifocal IOLs. These might improve with EDOF IOLs and low add powers.
Patients might not want to hear that they may not be totally spectacle independent postoperatively. However, explaining that before surgery results in fewer problems postoperatively. Patients also should be informed that a second procedure might be required, although in most cases that is unlikely.
“Every patient deserves to be informed of all available options whether you do it or not,” Dr. Braga-Mele said. “Obtaining informed consent to undergo any procedure should not be overlooked. Give them time to digest all of the information. The final choice of an IOL then can be made at the next visit or during a phone call.”
The IOL options Dr. Braga-Mele covers with her patients are the use of a standard IOL; aspheric approaches, which includes discussion of toric IOLs, relaxing limbal incisions; and astigmatic keratotomy, and premium lenses based on lifestyle that might result in less spectacle dependence.
Regarding the last, she emphasizes the higher costs and the possible need for extra testing. These choices include toric IOLs, multifocal IOLs, or those with a toric component for near-vision needs (ReSTOR family of +3.0 D and +2.5 D IOLs [Alcon Laboratories] and Tecnis +2.75 D, +3.25D, and +4.0 D IOL [Johnson & Johnson Vision]), EDOF IOL (Tecnis Symfony IOL, Johnson & Johnson Vision) with or without a toric component to provide intermediate vision, and trifocal IOLs (PanOptix IOL, Alcon Laboratories, and FineVision IOL, Bausch + Lomb) to provide a range of vision.
Dr. Braga-Mele also pointed out that if patients have been using monovision preoperatively, then monovision is a must postoperatively.
The Symfony IOL, an EDOF model that was approved in the United States in 2016, has diffractive echelletes, not zones, that are shaped (height and spacing) to elongate focus and reduce chromatic aberrations, thus providing less visual distortion at night and good contrast sensitivity. This IOL provides better intermediate vision at 48 cm than at 40 cm, but can improve the near acuity with mini-monovision.
The vision is plano in the dominant eye and -0.3 D to -0.55 D in the non-dominant eye. The IOL is also available with a toric component. It can be used if the corneal cylinder exceeds 1.00 D against-the-rule or 0.75 D with-the-rule astigmatism, according to Dr. Braga-Mele.
The recently available PanOptix IOL and FineVision IOL have a trifocal design. The former, which has the Enlighten Optical Technology platform, provides three add powers and redirects light from the third-step height to distance for more continuous vision, making it less dependent of the pupillary size.
The FineVision IOL provides near, intermediate, and distance vision at 33 cm, 60 cm, and more than 1 meter, respectively. The IOL combines two diffractive structures (+1.75 D and +3.5 D) with variable step heights from the center to the periphery. The distance vision increases with pupillary size.
With all the advances in technologies and the varying benefits they provide, patient selection is the key factor in obtaining the best visual outcomes after cataract surgery and IOL implantation.
Rosa Braga-Mele, MD, FRCSC
This article was adapted from a presentation the that Dr. Braga-Mele delivered at the 2017 American Society of Cataract and Refractive Surgery meeting. She is a consultant for Alcon Laboratories, Johnson & Johnson Vision, and Allergan.