Visual outcomes of patients bilaterally implanted with the extended range of vision intraocular lens: A prospective study

Abstract

Purpose:

The aim of this study was to analyze the objective and subjective visual outcomes of patients bilaterally implanted with the extended range of vision intraocular lens (EROV IOL), the Tecnis Symfony.

Methods:

This was a prospective interventional case series conducted at a tertiary eye care hospital in South India. The study included patients with bilateral implantation of EROV IOLs. The uncorrected and corrected visual acuity for distance, intermediate, and near vision was recorded at 6 weeks and 6 months’ postoperative visit. A subjective questionnaire was administered to assess spectacle independence, photic phenomenon, and overall satisfaction. All data were recorded using Microsoft Excel worksheet. The analyses were performed using SPSS for windows software.

Results:

Our study included fifty patients with bilateral implantation of EROV IOLs. The mean age was 59.84 ± 11.68 years. The mean uncorrected binocular distance, intermediate, and near visual acuity (in standard decimal equivalent) was 0.89,0.99 and 0.99 respectively, at 6 months’ postoperative visit. Ninety-six percent of the patients did not require spectacles for distance and 98% of the patients were free from spectacles for intermediate and near vision. 94% of our patients perceived no or minimal photic phenomena such as glare and halos. The mean subjective patient satisfaction score (out of 10) for distance, intermediate, and near was 9, 10, and 9, respectively.

Conclusion:

The EROV IOLs demonstrated high levels of spectacle independence for distance, intermediate, and near vision. The incidence of photic phenomena observed was minimal with a high level of patient satisfaction.

With advancements in technology and increased patient awareness, cataract surgery is fast evolving into a refractive procedure. Multifocal intraocular lenses (IOLs) afford postoperative spectacle independence by providing good visual acuity for both distance and near vision.[1] Traditional diffractive multifocal IOLs provide two distinct foci; one for distance and the other for near. They work on the principle of simultaneous vision which means at any point of time, one sharp image and another blurred image is projected onto the retina. Although one is able to suppress the blurred image and view the other image clearly in most situations, the out of focus image can produce dysphotopsia in dim illumination.[2,3,4]

A new concept of extended range of vision IOLs (EROV IOLs) has been designed to overcome limitations associated with traditional IOLs correcting presbyopia. This technology uses an elongated continuous range of focus and proprietary achromatic diffractive echelette design with an aim to provide superior visual results.

The aim of the current study was to analyze the subjective and objective visual outcomes of patients bilaterally implanted with the extended range of vision Tecnis Symfony IOL (Abbott Medical Optics, Inc.).

Methods

The study adhered to the tenets of the Declaration of Helsinki and an approval was obtained by the Ethics Committee of Our Institute. Informed consent was obtained from all the participants included in the study.

Patients with bilateral decrease of visual acuity attributed solely to cataract, seeking freedom from glasses postcataract surgery were included in the study. Other inclusion criteria included age >18 years and the availability to attend regular follow-up visits.

Exclusion criteria included ocular morbidities with a potential to affect visual outcomes, preoperative refractive astigmatism of −0.75 diopter or greater, previous ocular surgeries, amblyopia, and capsular or zonular abnormalities leading to potential postoperative IOL decentration or tilt.

Surgical technique

All surgeries were performed by the same experience surgeon(DR) under topical anesthesia using either standard phacoemulsification or femtosecond laser-assisted cataract surgery using the Catalys Precision Laser System (Optimedica, Abbott Medical Optics). The IOL power was calculated using the Holladay 2 formula (Verion Image Guided System, Alcon Novartis) for all ranges of axial length. A target refraction of emmetropia using the IOL power corresponding to the myopic outcome closest to zero was selected.

For cases undergoing conventional phacoemulsification, the Verion Image Guided System was used intraoperatively to provide an overlay for the construction of a uniformly sized capsulorrhexis (5 mm). The single piece Tecnis Symfony IOL (Abbott Medical Optics, Inc.) was implanted in the capsular bag with a uniform anterior capsular rim overlap. A minimum time interval of 1 week was provided before the contralateral cataract procedure.

Postoperative protocol included loteprednol etabonate 0.5% topical suspension tapered over 6 weeks and moxifloxacin hydrochloride eye drops 0.5% four times/day for a week.

Tecnis Symfony intraocular lens

The Tecnis Symfony (ZXR00) is a single piece, ultraviolet filtering hydrophobic acrylic material. The anterior surface has a negative asphericity of −0.27 mm with a posterior 5.5 mm achromatic diffractive surface. The diffractive echelette surface is a proprietary pupil-independent design that creates an elongated focus without defined focal planes throughout. The IOL has a high Abbe number, thereby correcting chromatic aberration and providing high-contrast sensitivity.

Postoperative examination

The patients were examined at day one, 6 weeks, and 6 months postoperatively. A detailed dilated slit-lamp examination to ascertain IOL centration and capsulotomy overlap was carried out at every visit. Intraocular pressures were recorded using Goldmann Applanation Tonometer. Binocular and monocular uncorrected and best-corrected visual acuity (BDVA) (in spherical decimal equivalent [SDE]) were recorded for distance (uncorrected distance visual acuity [UDVA] and corrected distance visual acuity [CDVA]), intermediate at 70 cm (uncorrected intermediate visual acuity [UIVA] and corrected intermediate visual acuity), and near at 40 cm (uncorrected near visual acuity [UNVA] and corrected near visual acuity). Contrast sensitivity was evaluated for both mesopic and scotopic pupils (ETDRS Contrast, Aurochart, Aurolab, India).

A subjective questionnaire was administered to all the patients. Nondirected and directed questions regarding photic phenomena were raised. Symptoms of glare, starburst, and haloes were categorized as nil, mild, moderate, or severe. Need for spectacles as percentage of time during the day (0%, 25%, 50%, 75%, or 100%) was recorded for distance, intermediate, and near. Patients were asked to grade their level of satisfaction of vision for all distances, from least (score = 0) to most satisfied (score = 10). They were also questioned as to whether they would choose the same IOL again and recommend it to their family. The surgeon was questioned regarding the ease of handling and implantation of the IOL.

Statistical analysis

All data was recorded in Microsoft Excel worksheet. The analyses were performed using SPSS for windows software (Version 15.0, International Business Machine Corp.,).

Results

We conducted a prospective interventional case series including 100 eyes of 50 patients bilaterally implanted with the Tecnis Symfony IOL. All patients completed a follow up of 4-6 months. Table 1 summarizes the demographic and refractive data.

Table 1.

Patient demographics and refractive status

Visual outcomes and spectacle independence

At 4–6 months follow-up, the mean UDVA and CDVA was 0.89 ± 0.19 and 0.97 ± 0.23, respectively. The mean UIVA and UNVA was 0.99 ± 0.13 and 0.99 ± 0.16 SDE, respectively, at similar follow-up points. The distribution of binocular vision for distance, intermediate, and near vision at 6 months’ follow-up visit has been shown in Fig. 1.

Figure 1.

Distribution of best-corrected distance, intermediate, and near vision at 6 months’ postoperative visit

Patients were questioned regarding their need for glasses for distance, intermediate, and near activities. At the 6-week follow-up visit, none of the patients required glasses for near or intermediate activities, whereas two patients required glasses for distance half of the time or more. At the 4–6 months’ follow-up visit, one patient required glasses frequently for near and intermediate tasks, whereas two patients continued to use glasses regularly for distance vision (mean spherical equivalent −0.75 Diopters) [Fig. 2].

Figure 2.

Need for spectacles (as percentage of time during the day) at 6 months’ postoperative visit

Optical or visual symptoms

Patients showed a high degree of satisfaction with visual quality. At 6 weeks’ follow-up visit, only one patient complained of glare and haloes on nondirected questioning. On directed questioning, two patients had symptoms of moderate glare and one patient had symptoms of moderate halos. The remaining patients had no/minimal photic phenomena and were comfortable with night driving as well. The symptoms persisted for three of the four patients at 4–6 months’ follow-up visit [Fig. 3].

Figure 3.

Photic phenomena at 6 months postoperative visit

Contrast sensitivity

Table 2 summarizes the contrast sensitivity (low and high contrast) for both scotopic and mesopic conditions at 6 weeks’ postoperative visit.

Table 2.

ETDRS contrast sensitivity at 6 week's postoperative visit

Complications and/or adverse events

No postoperative complications were noted in any of the cases. There were no cases of IOL decentration or tilt over a 6-month follow-up. One eye required neodymium-doped yttrium aluminium garnet capsulotomy for a visually significant posterior capsular opacification (loss of two Snellen's lines of BDVA) at 4-months’ postoperative visit.

Patient and surgeon satisfaction

The patients rated their satisfaction with their uncorrected visual outcomes on a scale of 0–10 (0 = not at all satisfied and 10 = very satisfied). The median patient satisfaction scores for distance, intermediate, and near vision were 9, 10, and 9, respectively. Ninety-six percent of the patients agreed to choosing the same IOL again and recommending it to their friends and family. Surgeon satisfaction over handling and implanting the IOL was high with a score of 10. The assessment of achievement of target refraction, visual performance, and overall satisfaction was 9.

Discussion

Cataract surgery is fast evolving into a refractive procedure with increased patient expectations for unaided distance and near vision alike. Diffractive multifocal IOLs provide two distinct foci for distance and near, with compromised intermediate visual acuity.[5] Low add multifocal lenses may help in achieving superior unaided intermediate vision but may compromise near visual acuity.[6] The Tecnis Symfony IOLs with its proprietary echelette design provides an elongated range of focus rather than individual focal points, resulting in potentially superior intermediate vision and reduced photic phenomena such as glare and halos.[7]

Our results demonstrated a mean UDVA of 0.89 (SDE) at 6 months’ postoperative visit. This was marginally lower than a UDVA of 0.94 achieved in the Concerto multicenter study.[8] The mean UIVA of 0.99 achieved in our study was superior to that achieved in multiple studies reporting their results with bifocal and trifocal IOLs.[9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26] The mean binocular UNVA (at 40 cm) of 0.99 (LogMAR 0.01) reported in our study was similar to or superior to results obtained with apodized and bifocal diffractive IOLs.[13,14,15,17,18,19] The UNVA was found to be consistent and patients did not show preference for either eye even if slight residual error was remaining. Law et al. reported a mean binocular UNVA of Log MAR 0.16 while using trifocal diffractive IOLs which combine bifocal and trifocal diffractive patterns.[13] Alió et al. reported a mean monocular UNVA of 0.26 with a trifocal IOL.[17] Chang et al. demonstrated a mean UDVA, UIVA, and UNVA of Log MAR 0.10, 0.43, and 0.18, respectively, using a diffractive multifocal IOL.[27] Our study demonstrates superior visual outcomes as compared to other presbyopia-correcting IOLs.

In our study, superior visual outcomes were additionally associated with high levels of spectacle independence. The need for glasses was consistently low in the entire cohort. At 6-months’ follow-up visit, one patient required glasses for near or intermediate activities and two patients required glasses for distance half the time or more. These results are similar to those achieved in a multicentric study using the same IOL, with slightly greater spectacle independence for near and intermediate vision.[8]

At 6 weeks’ postoperative visit, 92% of our patients experienced nil or mild photic phenomena while 98% of the patients did not complain of photopic phenomena on indirect questioning. At the 6 months’ postoperative visit, only three patients experienced visually significant glare and halos which hampered daily activities and night driving. The incidence of disturbing photic phenomenon was minimal in our study as compared to the results published in earlier studies with other presbyopia-correcting IOLs. Visser et al. reported a 50% incidence of glare, halos, and starbursts in patients implanted with a toric diffractive multifocal IOL.[28] Law et al. reported the results following implantation of a diffractive trifocal IOL, with an incidence of halos in 80% of the patients at 1-month postoperative visit.[13] Lubiński et al. reported a low level of halo perception in 75% of the patients while evaluating the results of a diffractive bifocal IOL.[11] Chang et al. reported the results following implantation of a multifocal diffractive IOL.[27] Seventy-eight percent, 26% and 48% of the patients reported postoperative halos, glare, and starburst, respectively. However, as the methods of questioning and measuring photic phenomenon are not standardized, a direct comparison cannot be made conclusively.

Overall patient satisfaction scores were encouraging with high subjective scores of 9, 10, and 9 for distance, intermediate, and near visual acuity, respectively. One hundred percent of the patients were highly satisfied with intermediate visual acuity and 96% of them agreed they would choose the same IOL again and would also recommend the lens to family and friends.

The Tecnis Symfony EROV IOLs demonstrate superior binocular uncorrected visual acuity for all distances. These results were associated with a high level of spectacle independence. In addition, the incidence of optical visual symptoms was within the typical incidence observed with monofocal IOLs. Satisfaction rates were high for both the patients and the surgeon.

Conclusion

The combined mechanism achieving an extended range of focus and achromatic design enables superior outcomes in comparison to diffractive multifocal IOLs.

Financial support and sponsorship

Dr. Ramamurthy Dandapani received study grant from Abbott Medical Optics during the duration of this study.

Conflicts of interest

There are no conflicts of interest.