Several factors must be considered when choosing an IOL. These can be categorised into three main areas: psychological, physiological, and surgeon experience.

PSYCHOLOGICAL CONSIDERATIONS

The patient’s visual priorities, personality, and previous refractive experience all play crucial roles in the choice of IOL.

What are the patient’s visual priorities? Some patients would prefer to be spectacle free for certain activities, while others are happy to wear glasses and prefer minimal optical side effects.

What personality traits does the patient have? Stereotypically, engineers often notice every optical detail, whereas a surfer may be more accepting of optical side effects such as haloes, starbursts, and glare.

What was the patient’s pre-operative spectacle prescription? Hypermetropic patients often have lower expectations of spectacle independence, while myopic patients may find it difficult to compromise their unaided near vision postoperatively.

Finally, if the patient has already undergone lens replacement surgery in one eye, the type of lens that was used should be considered, as it will influence the patient’s overall visual experience.

PHYSIOLOGICAL STATUS OF THE EYE

It is essential to carefully evaluate for ocular comorbidities. Does the level of cataract match the degree of vision reduction? If not, other causes of visual dysfunction must be considered. Optical coherence tomography (OCT) should be performed prior to cataract surgery to exclude macular pathology.

Incidental findings of epiretinal membrane (ERM), macular holes, central macular oedema (CMO), and age-related macular degeneration (AMD) are often uncovered. Diagnosing these macular pathologies allows the surgeon to set realistic expectations for the patient and, in some cases, treat the macular pathology before cataract surgery, reducing the likelihood of poor visual outcomes. Other factors such as ocular surface disease, pupil abnormalities, previous ocular inflammatory episodes, and prior retinal surgery should also be considered. Finally, optic nerve pathology should be ruled out when vision loss does not correlate with cataract severity, and a relative afferent pupillary defect should be assessed in such cases, prior to pupil dilatation.

SURGEON EXPERIENCE

The surgeon’s familiarity with different IOLs is critical. Whether it is a standard toric posterior chamber IOL, a three-piece sulcus IOL, or scleral-fixated sutured IOL, the surgeon must be technically confident in inserting and manipulating the lens within the eye. They should also have a clear understanding of the lens’ capabilities and potential optical side effects. Not all multifocal or EDOF lenses are the same, and each has its own nuances and side-effect profile. Experience with the IOL allows the surgeon to provide the patient with realistic expectations regarding their visual outcome and potential side effects.

In my experience, most cataract surgeries are technically straightforward. However, while rare, patient dissatisfaction is more likely to occur when these psychological or physiological factors are not considered prior to surgery.

INTRAOCULAR LENS OPTIONS

When discussing refractive options, IOLs can be placed into four broad categories along a spectrum of presbyopia correction: monofocal, multifocal (MF), enhanced monofocal, and EDOF IOLs.

Monofocal Lenses

Monofocal IOLs provide clear unaided vision for a single targeted focal point with minimal optical side effects. Targeting emmetropia will necessitate glasses for all intermediate and near tasks, whereas targeting near will produce the best unaided reading vision though requires glasses for most other activities.

Monovision improves spectacle independence by targeting the dominant eye for emmetropia and the non-dominant eye for mild myopia (e.g. -1.50D). While effective, some patients struggle with anisometropia and aniseikonia, leading to reduced stereopsis and adaptation issues. Trial contact lenses remain a valuable tool in assessing suitability before surgery.

Multifocal Lenses

In use since the late 1990s, with the first trifocal lens available in 2010, these lenses allow complete spectacle independence at distance, intermediate, and near. However, they are associated with more optical side effects such as glare, flare, haloes, and starbursts. They are also less tolerant to postoperative residual refractive error and are generally avoided in patients with ocular comorbidities such as macular pathology or glaucoma. Commonly used multifocal IOLs (MFIOLs) in Australia include the Alcon PanOptix, ZEISS At Lisa, and Tecnis Synergy.

Enhanced Monofocal Lenses

Enhanced monofocal lenses are a new addition to the surgeon’s repertoire. These lenses provide intermediate vision that falls between that of monofocal and EDOF lenses, while maintaining the optical quality of traditional monofocal lenses. Examples include the Rayner EMV, Bausch and Lomb LuxSmart, and Tecnis Eyhance.

EDOF Lenses

Introduced in 2014, these lenses aim to reduce photic phenomena such as glare and haloes while maintaining good distance and intermediate vision. The patient is usually spectacle free for distance and intermediate tasks, however usually requires glasses for fine near vision. Examples include the Tecnis Symfony, ZEISS At Lara, Alcon Vivity, and Tecnis Puresee.

HOW DO INTRAOCULAR LENSES WORK?

Monofocal IOLs focus light onto a single point. This focal point can be targeted for any preference, such as emmetropia for good distance vision or myopia (e.g. -2.50D) for good near vision.

MFIOLs can be refractive, diffractive, or a hybrid, and work by splitting light into either two or three discrete focal points. Diffractive IOLs generate multiple focal points using a series of annular concentric grooves in a radial pattern to create light interference. Trifocal lenses aim to provide the patient with unaided vision for near, intermediate, and distance. The Alcon PanOptix IOL is a diffractive aspheric optic with focal points at 40 cm, 60 cm, and distance.1

EDOF lenses create a single, continuous, and elongated focal point from far to near to enhance the depth of focus.2 EDOF IOLs theoretically provide a continuous range of focus, avoiding the presence of secondary out-of-focus images. However, by spreading the image across a range of distances, the sharpness of the image at any one point is compromised. There is a limit to how far the depth of focus can be extended before the image is degraded, thus near vision is compromised to maintain the quality of the image throughout.

The American Academy of Ophthalmology has introduced a definition of EDOF lenses that stipulates that the optical profile must be continuous, without a change in transition, whether refractive or diffractive. Pure EDOF lenses use either induced spherical aberration (SA) or small apertures to utilise the pinhole effect to increase the depth of focus. The Bausch and Lomb IC-8lens is an example of a pinhole IOL. Many lenses advertised as EDOF also use chromatic aberration, diffraction, or an additional power add to increase near vision and should technically be classified as hybrid EDOF-MFIOLs. The Tecnis Symfony lens uses diffractive achromatic technology with multiple diffractive zones or echellettes to provide approximately +1.75D of near vision. The Tecnis Synergy IOL is more precisely a bifocal IOL that incorporates EDOF optical principles to improve intermediate vision in the hope of offering more visual continuity than traditional trifocal lenses.

Refractive EDOFs work by varying the geometry of a central zone within the optic to either alter the refractive power of the lens or to modulate the wavefront. The Alcon Vivity lens is a non-diffractive EDOF using proprietary X-wave technology to shift and stretch light without splitting it. It also incorporates a central plateau, which is more pronounced at 2 mm, as well as aspheric technology. The Tecnis Puresee lens is described as a purely refractive lens, using its anterior surface to correct for SA and its posterior surface to create a continuous change in power to extend the depth of focus.3

Enhanced monofocal lenses, like the Tecnis Eyhance, also incorporate a central plateau to alter the refractive power while employing primary negative SA. The Bausch and Lomb LuxSmart is a non-diffractive aspheric IOL that utilises an EDOF centre with a transition zone and a monofocal aberration-neutral periphery. The RayOne EMV increases SA, and similarly, the outer periphery behaves as aberrationneutral to reduce longitudinal SA, providing around 1.25D of extended visual range.

INFLUENCE OF MACULAR PATHOLOGY ON LENS SURGERY

Macular pathology requiring treatment should generally be managed prior to cataract surgery. Choroidal neovascularisation in neovascular AMD and macular holes are time sensitive and should be prioritised over cataract removal. Additionally, macular oedema from diabetic retinopathy or retinal vein occlusions (RVO) is often exacerbated by intraocular surgery, while untreated epiretinal membrane can increase the risk of postoperative macular swelling. However, in some cases, vitreoretinal pathology and cataracts can be addressed simultaneously with a combined pars plana vitrectomy and cataract surgery.

Determining visual prognosis and the likelihood of macular disease progression is essential in selecting the appropriate IOL. If the macular disease is stable with a good prognosis, a wider range of IOL options is available compared with the options available for a patient with progressive macular disease and a guarded visual prognosis. If the macular pathology is likely to cause reduced contrast sensitivity, then multifocal IOLs that further reduce contrast sensitivity should be avoided. In the absence of objective contrast sensitivity testing, the presence of metamorphopsia can act as a surrogate and help predict subjective patient visual experience postoperatively. I am more confident implanting complex IOL optics if there are no subjective distortion symptoms preoperatively.

A discussion with the patient is necessary to set realistic visual expectations and determine whether a presbyopia-correcting IOL is appropriate for an eye with reduced visual acuity. I believe that it is still worthwhile considering a presbyopia correcting-IOL in patients with poor visual prognosis for the simple reason that improved intermediate vision will probably reduce falls risk, which is especially important in patients with reduced visual function.

It is also important to acknowledge that certain lenses increase the difficulty of performing vitreoretinal surgery. An implanted MFIOL can significantly impair visibility for the surgeon during vitreoretinal surgery, and some studies have demonstrated an increased rate of iatrogenic retinal breaks with diffractive MFIOLs.4 Finally, hydrophilic lenses should be avoided in patients who may require a gas tamponade post-vitrectomy, while silicone lenses should not be used in cases where silicone oil may be required.

CONTRAST SENSITIVITY IN MACULAR PATHOLOGY AND IOL SELECTION

Contrast sensitivity testing quantifies the patient’s ability to distinguish lightness or darkness and distinguish objects from their background, offering a more functional assessment of vision compared to standard visual acuity testing.5 This is particularly relevant for real-world activities such as facial recognition, driving, walking, and reading. Patients with normal visual acuity may still experience reduced contrast sensitivity, which can explain dissatisfaction following cataract surgery despite good uncorrected visual acuity.

Despite its relevance, contrast sensitivity testing is rarely performed in routine clinical practice. The Pelli-Robson chart is limited to one spatial frequency, whereas the Functional Acuity Contrast Test and Vistech have poor range and poor test-retest reliability. However, the quantitative contrast sensitivity function method is emerging as a promising clinical tool, offering better test reliability, testing at multiple spatial frequencies, and only takes two minutes per eye.

Macular pathology is known to reduce contrast sensitivity with different conditions impacting different spatial frequency ranges. It has been shown that in patients with geographic atrophy and neovascular AMD, contrast sensitivity is often maintained at lower spatial frequencies but can be severely affected at higher spatial frequencies. Both central and branch RVO with macular oedema have been shown to exhibit reduced contrast sensitivity and this appears to be related to disorganisation of the inner retinal layers. Contrast sensitivity is also reduced in patients with previously treated macula off retinal detachments and is more strongly associated with central macular thickness than visual acuity in patients with diabetic macular oedema. However, one study showed that patients with early stage AMD and ERM had the same contrast sensitivity as patients with a normal macula, indicating that the severity of macular pathology is likely correlated with the level of contrast sensitivity reduction.6

Due to the different optical techniques utilised in presbyopia-correcting IOLs, it is thought that certain IOL designs can lead to reduced contrast sensitivity. It is generally accepted that monofocal lenses provide better contrast sensitivity compared to MFIOLs, as MFIOLs split light into multiple focal points, reducing light efficiency and retinal image contrast.7 While some studies, such as the review by Gryzbowski et al.8 suggest that MFIOLs do not necessarily need to be avoided in patients with macular pathology, others have shown reduced visual quality, even in eyes with non-foveal ERMs.9

EDOF IOLs tend to cause fewer visual disturbances because they stretch rather than split the light. Several studies have concluded that EDOF IOLs provide better contrast sensitivity compared to MFIOLs, both in photopic and mesopic conditions.10 Manufacturer data from Tecnis suggests its new refractive EDOF lens has a contrast sensitivity profile comparable to monofocalplus lenses within the 1.5 to 12 cycles per degree range. One study showed that eyes with mild ERM implanted with the Alcon Vivity IOL had the same post-operative contrast sensitivity as eyes without macular pathology.11However, another study concluded that Symfony, PanOptix, and Vivity all had reduced mesopic contrast sensitivity at higher spatial frequencies compared to a monofocal lens.12

A study by Wan et al. concluded that enhanced monofocal IOLs did not compromise contrast sensitivity compared to a monofocal IOL.13 A South Korean study evaluating Eyhance versus standard monofocal IOLs in patients undergoing combined cataract and ERM surgery reported similar contrast sensitivity outcomes between the two groups.14

PRESENT AND FUTURE OF IOL SELECTION IN MACULAR DISEASE

In my practice, all patients – including those referred for cataract surgery – routinely undergo macular OCT, wide-field retinal photography, and fundus autofluorescence. A significant proportion of my cataract patients present with macular pathology, including AMD, retinal dystrophies, ERMs, macular holes, and previously treated retinal detachments. While conventional wisdom suggests that these patients should only receive monofocal lenses, I have been exploring the feasibility of using presbyopia correcting IOLs in this cohort.

Since mid-2024, I have been implanting a newer refractive EDOF IOL in a broad range of patients. Initially, I reserved this lens for pristine eyes with no ocular pathologies, but as outcomes have remained positive, I have progressively expanded its use to include mild macular pathology cases with no subjective distortion. Thus far, these patients have all achieved good objective and subjective visuals outcomes, with no reports of reduced contrast sensitivity.

After reviewing the literature, and analysing my own surgical outcomes, I am increasingly confident in using refractive EDOF IOLs in moderate to severe macular pathology. I inform patients that, while evidence remains limited, theoretical concerns pertaining to reduced contrast sensitivity have not translated into significant real-world complaints in my experience. Anecdotally, my patients with macular pathologies are very happy with their outcomes.

My team, including Dr Anna Waldie, is currently conducting a retrospective and prospective study assessing contrast sensitivity, visual acuity, and patient-reported visual quality following refractive EDOF implantation in patients with macular pathology. We hypothesise that refractive EDOFs are safe and should be considered in these cases. Future studies will compare contrast sensitivity outcomes between monofocal and EDOF IOLs in patients with and without macular disease. Additional research is also required to explore the use of refractive EDOF IOLs in conditions such as glaucoma and post-refractive laser surgery, where contrast sensitivity deficits may already be present.

With an ageing Australian population and improved diagnostic capabilities, the number of patients with both cataract and macular pathology will continue to grow. It is likely that MFIOLs worsen contrast sensitivity and a conservative approach to their use in patients with macular disease is recommended, however enhanced monofocal and refractive EDOF IOLs appear to maintain contrast sensitivity in most spatial frequencies. These lenses represent a promising alternative for those historically excluded from presbyopia-correcting IOLs and should be considered in patients with mild to moderate macular pathology.

To earn your CPD hours from this article visit: mieducation.com/what-happens-when-yourcataract-patient-also-has-a-macular-disease.

References

1. Gundersen KG, Potvin R. Trifocal intraocular lenses: a comparison of the visual performance and quality of vision provided by two different lens designs. Clin Ophthalmol. 2017;11:1081-1087. doi: 10.2147/OPTH.S136164.
2. Kanclerz P, Toto F, Grzybowski A, Alio JL. Extended depth-of-field intraocular lenses: An update. Asia Pac J Ophthalmol (Phila). 2020;9(3): 194-202. doi: 10.1097/APO.0000000000000296.
3. Corbett D, Black D, Vilupuru S, et al. Quality of vision clinical outcomes for a new fully-refractive extended depth of focus Intraocular Lens. Eye (Lond). 2024 May;38(Suppl 1):9-14. doi: 10.1038/s41433-024-03039-8. Erratum in: Eye (Lond). 2025 Jan;39(1):202. doi: 10.1038/s41433-024-03421-6.
4. Patel SB, Snyder ME, Sisk RA, et al. Combined phacoemulsification surgery with multifocal intraocular lens implantation and pars plana vitrectomy for symptomatic vitreous opacities. Retin Cases Brief Rep. 2021;15(6):724-729. doi: 10.1097/ICB.0000000000000873.
5. Vingopoulos F, Kasetty M, Miller JB, et al. Active learning to characterize the full contrast sensitivity function in cataracts. Clin Ophthalmol. 2022;16:3109-3118. doi: 10.2147/OPTH.S367490.
6. Kaymak H, Neller K, Klabe K, et al. Contrast adaptation in pseudophakic patients with macular disorders. Curr Eye Res. 2024; 49(2):207-213. doi: 10.1080/02713683.2023.2273196.
7. Cao K, Friedman DS, Wan XH, et al. Multifocal versus monofocal intraocular lenses for age-related cataract patients: a system review and meta-analysis based on randomized controlled trials. Surv Ophthalmol. 2019;64(5):647-658. doi: 10.1016/j.survophthal.2019.02.012.
8. Grzybowski A, Kanclerz P, Tuuminen R. Multifocal intraocular lenses and retinal diseases. Graefes Arch Clin Exp Ophthalmol. 2020;258(4):805-813. doi: 10.1007/s00417-020-04603-0.
9. Kim B, Kwon S, Choi A, Jeon S. Influence of mild non-foveal involving epiretinal membrane on visual quality in eyes with multifocal intraocular lens implantation. Graefes Arch Clin Exp Ophthalmol. 2021;259(9):2723-2730. doi: 10.1007/s00417-021-05225-w.
10. Li J, Sun B, Jiang S, et al. Comparative efficacy and safety of all kinds of intraocular lenses in presbyopia-correcting cataract surgery: a systematic review and meta-analysis. BMC Ophthalmol. 2024;24(1):172. doi: 10.1186/s12886-024-03446-1.
11. Jeon S, Choi A, Kwon H. Clinical outcomes after implantation of extended depth-of-focus AcrySof Vivity intraocular lens in eyes with low-grade epiretinal membrane. Graefes Arch Clin Exp Ophthalmol. 2022; 260(12):3883-3888. doi: 10.1007/s00417-022-05751-1.
12. Schallhorn JM, Pantanelli SM, Rose-Nussbaumer JR, et al. Multifocal and Accommodating Intraocular Lenses for the Treatment of Presbyopia: A Report by the American Academy of Ophthalmology. Ophthalmology. 2021;128(10):1469-1482. doi: 10.1016/j.ophtha.2021.03.013.
13. Wan KH, Au ACK, Chow VWS, et al. Enhanced monofocal versus conventional monofocal intraocular lens in cataract surgery: A meta-analysis. J Refract Surg. 2022;38(8):538-546. doi: 10.3928/1081597X-20220707-01.
14. Choi SH, Cho IH, Hong IH, et al. Comparative evaluation of visual outcomes in combined cataract and vitrectomy for idiopathic epiretinal membrane with an advanced or conventional intraocular lens. Ophthalmic Res. 2024;67(1):221-231. doi: 10.1159/000538316.