Journal of Refractive Surgery

Original Article Supplemental Data

Higher Order Aberrations in Femtosecond Laser–Assisted Versus Manual Cataract Surgery: A Retrospective Cohort Study

Paul H. Ernest, MD; Marko Popovic, MD; Matthew B. Schlenker, MD; Lindsay Klumpp, OD; Iqbal Ike K. Ahmed, MD

Abstract

PURPOSE:

To evaluate differences in higher order aberrations (HOAs) between femtosecond laser–assisted cataract surgery (FLACS) and manual cataract surgery.

METHODS:

In this retrospective cohort study, consecutive patients undergoing FLACS or manual cataract surgery with implantation of an intraocular lens from January 2017 to February 2018 were recruited. Patients underwent aberrometry testing at least 2 months postoperatively. The primary endpoint was internal coma < 0.32 µm, and secondary outcomes included patient-reported vision quality. Generalized estimating equations accounting for within-patient correlation were used for analysis.

RESULTS:

A total of 57 eyes underwent FLACS (mesopic pupil size: 4.74 ± 1.37 mm) and 50 eyes underwent manual cataract surgery (pupil size: 4.99 ± 1.24 mm). The proportion of eyes reaching internal coma < 0.32 µm was significantly greater following FLACS (54 of 57 eyes, 94.7%) relative to manual cataract surgery (39 of 50 eyes, 78.0%) (odds ratio [OR] = 5.08, 95% confidence interval [CI] = 1.24 to 20.85, P = .024). The median internal coma was 0.10 µm for FLACS and 0.12 µm for manual cataract surgery (P = .005). There were no significant differences in vision quality between treatments (P = .40). All eyes (n = 15) with satisfaction scores of 0 to 10 had internal coma < 0.20 µm, compared to those with scores of 11 to 20 (27 of 29 eyes, 93.1%), 21 to 30 (19 of 30 eyes, 63.3%), and > 30 (8 of 15 eyes, 53.3%) (P < .001). The average internal coma increased by a greater amount for manual cataract surgery than for FLACS for every increase in mesopic pupil size > 5.75 mm.

CONCLUSIONS:

More eyes achieved internal coma < 0.32 µm following FLACS compared to manual cataract surgery. However, this does not account for improved patient-reported vision quality. There was a correlation between internal coma and patient-reported satisfaction, and eyes with excellent patient satisfaction all had internal coma < 0.20 µm.

[J Refract Surg. 2019;35(2):102–108.]

Abstract

PURPOSE:

To evaluate differences in higher order aberrations (HOAs) between femtosecond laser–assisted cataract surgery (FLACS) and manual cataract surgery.

METHODS:

In this retrospective cohort study, consecutive patients undergoing FLACS or manual cataract surgery with implantation of an intraocular lens from January 2017 to February 2018 were recruited. Patients underwent aberrometry testing at least 2 months postoperatively. The primary endpoint was internal coma < 0.32 µm, and secondary outcomes included patient-reported vision quality. Generalized estimating equations accounting for within-patient correlation were used for analysis.

RESULTS:

A total of 57 eyes underwent FLACS (mesopic pupil size: 4.74 ± 1.37 mm) and 50 eyes underwent manual cataract surgery (pupil size: 4.99 ± 1.24 mm). The proportion of eyes reaching internal coma < 0.32 µm was significantly greater following FLACS (54 of 57 eyes, 94.7%) relative to manual cataract surgery (39 of 50 eyes, 78.0%) (odds ratio [OR] = 5.08, 95% confidence interval [CI] = 1.24 to 20.85, P = .024). The median internal coma was 0.10 µm for FLACS and 0.12 µm for manual cataract surgery (P = .005). There were no significant differences in vision quality between treatments (P = .40). All eyes (n = 15) with satisfaction scores of 0 to 10 had internal coma < 0.20 µm, compared to those with scores of 11 to 20 (27 of 29 eyes, 93.1%), 21 to 30 (19 of 30 eyes, 63.3%), and > 30 (8 of 15 eyes, 53.3%) (P < .001). The average internal coma increased by a greater amount for manual cataract surgery than for FLACS for every increase in mesopic pupil size > 5.75 mm.

CONCLUSIONS:

More eyes achieved internal coma < 0.32 µm following FLACS compared to manual cataract surgery. However, this does not account for improved patient-reported vision quality. There was a correlation between internal coma and patient-reported satisfaction, and eyes with excellent patient satisfaction all had internal coma < 0.20 µm.

[J Refract Surg. 2019;35(2):102–108.]

Femtosecond laser–assisted cataract surgery (FLACS) is a new technology purported to improve the accuracy and safety of cataract surgery relative to manual approaches. Using a femtosecond laser, photodisruption and photoionization of optically transparent tissue is produced using an acoustic shock wave.1 FLACS has been used for various stages in the procedure, including the corneal incisions, capsulotomy, and lens fragmentation.

There has been an increasing interest in FLACS among both patients and surgeons. This has been particularly attributable to its potential impact on visual, refractive, and safety outcomes due to reduced phacoemulsification time, improved wound architecture, greater accuracy and precision of the capsulotomy, and more predictable positioning of the intraocular lens (IOL) relative to manual cataract surgery.2–6 However, empirical evidence has generally not supported the superiority of FLACS over manual cataract surgery. A meta-analysis by our team in 2016 of 14,567 eyes showed that there were no significant differences detected between FLACS and manual cataract surgery for patient-reported visual and refractive outcomes, as well as for overall complications.7 This was despite the improved effective phacoemulsification time, capsulotomy circularity, postoperative central corneal thickness, and corneal endothelial cell reduction following FLACS. Additionally, it was shown that FLACS was associated with significantly higher prostaglandin concentrations and higher rates of posterior capsular tears.

Optical quality is a subjective entity that may only be described from indirect metrics, such as wavefront error measurements, visual acuity, and contrast sensitivity.8–11 In wavefront analysis, the effects of lower order aberrations such as defocus and astigmatism on optical quality are isolated from other higher order aberrations (HOAs).3 In general, HOAs can produce vision errors such as difficulty with night vision and the presence of glare, halos, visual blurring, starburst patterns, or diplopia.

Given the limited data that currently exist evaluating differences in HOAs between FLACS and manual cataract surgery, we performed a retrospective cohort study to investigate this issue.

Patients and Methods

Recruitment Process

Consecutive patients with cataract undergoing either FLACS (LenSx Laser System; Alcon Laboratories, Inc., Fort Worth, TX) or manual cataract surgery (Infiniti Vision System; Alcon Laboratories, Inc.) from January 2017 to February 2018 were recruited from the Specialty Eye Institute, Jackson, Michigan. Patients were only included if they had any HOA measurements performed. A local institutional review board provided approval for this study, and the study adhered to the principles of the Declaration of Helsinki.

Surgical Procedure

Square posterior limbal incisions (2.3 × 2.3 mm) were made at the junction of the posterior limbus and anterior sclera. Additional corneal incisions were performed only if there was preoperative astigmatism. Limbal relaxing incisions, where appropriate, were made 7.8 to 8 mm from the optical center of the cornea. For correction of astigmatism, the incisions made did not necessarily need to be on the axis, given the square architecture of the wound. For all cases of astigmatic correction, the following parameters were used: (1) with-the-rule = astigmatism of up to 1.50 diopters (D), (2) oblique = astigmatism of up to 1.25 D, and (3) against-the-rule = astigmatism of up to 1.00 D. For FLACS cases, both the capsulotomy and lens fragmentation were performed with the femtosecond laser. All included implants were either the TECNIS Symfony (Johnson & Johnson Vision, Santa Ana, CA) or AcrySof IQ ReSTOR +2.50 D (Alcon Laboratories, Inc.).

Postoperative Examinations

Patients underwent routine postoperative evaluations with aberrometry testing performed using the NIDEK OPD-Scan III aberrometer (NIDEK Co. Ltd., Gamagori, Japan) at least 2 months after surgery. This device is able to measure corneal, internal, and total optical aberrations, as well as the autorefraction, keratometry, photopic and mesopic pupil sizes, and corneal topography concurrently for the same axis. Wavefront aberrations were recorded relative to the corneal vertex and reconstructed with the use of a sixth order Zernike polynomial decomposition. For our analysis, the mesopic setting was used. Eyes were not dilated to ensure a more representative measurement of the typical aberration of each eye.

The Quality of Vision questionnaire, a 30-item measure assessing patient satisfaction with vision, was administered postoperatively to patients in both groups.12 The following categories were examined by the Quality of Vision questionnaire: glare, halos, star-burst, hazy vision, blurred vision, distortion, multiple images, fluctuation in vision, focusing difficulties, and depth perception. For this instrument, four variations are provided on each item (0 = not a problem, 1 = mild, 2 = moderate, and 3 = severe), for a total score ranging from 0 to 90 with 0 representing the best possible outcome.

Outcome Measures

The primary endpoint was the difference in internal coma between treatment comparators, analyzed as a categorical (normal < 0.32 µm) variable.13 Internal coma was chosen because of its ability to accurately measure microtilt from asymmetrical overlap of the anterior capsule on the optic. Coma aberrations typically form an image of a blurred spot with a comet-shaped tail, which results from either incident wavefront tilt or decentration relative to the optical surface.3 Secondary endpoints included internal coma as a continuous variable, as well as trefoil, which is an HOA that causes a point of light in an image to be distorted in three different directions.14 Angle alpha, defined as the difference between the center of the limbus and visual axis, was also examined. Scores from the Quality of Vision questionnaire were analyzed for differences between treatments, and were correlated to internal coma scores irrespective of treatment modality.

Statistical Analysis

Continuous characteristics were represented with medians and mean ± standard deviation (SD) as appropriate, mean differences (MDs), and 95% confidence intervals (95% CIs). To evaluate the difference in continuous internal coma and secondary endpoints between treatments, generalized estimating equations (GEEs) that accounted for within-patient correlation were computed using a scale linear model. The Wilcoxon rank-sum test was used as a non-parametric alternative for continuous variables.

Categorical variables were described using proportions, odds ratios (ORs), and 95% CIs. The proportion of eyes with internal coma less than 0.32 µm was compared between FLACS and manual cataract surgery using GEEs that accounted for within-patient correlation with a binary logistic model. Using the same model, the association of internal coma and patient satisfaction scores with other baseline parameters (ie, 65 years or younger, gender, IOL model, average keratometry 44.00 D or less, and postoperative cylinder of 0.25 D or less) was analyzed. GEEs were also used to investigate the relationship between internal coma of less than 0.20 and less than 0.32 µm with Quality of Vision patient satisfaction scores. SPSS Statistics software (version 23.0; IBM, Armonk, NY) was used for all analyses, and a P value of .05 was used throughout to indicate statistical significance.

Results

Baseline Characteristics

A total of 34 patients (57 eyes) underwent FLACS and 26 patients (50 eyes) received manual cataract surgery at our center (Table 1). The median patient age was 66.0 ± 6.3 years for FLACS and 68.5 ± 7.8 years for manual cataract surgery. There was a similar gender distribution between groups, with females representing 61.4% of eyes in the FLACS group and 64% of eyes in the manual cataract surgery group. Twenty-five eyes (43.9%) receiving FLACS and 25 eyes (50.0%) receiving manual cataract surgery were right eyes. Overall, there were 82 eyes implanted with the TECNIS Symfony IOL and 25 eyes with the AcrySof IQ ReSTOR +2.50 D IOL. Average preoperative keratometry, postoperative spherical equivalent, and visual acuity were similar between groups.

Demographic Data Stratified by Treatment

Table 1:

Demographic Data Stratified by Treatment

Internal Coma

All included eyes had applicable values for internal coma (Figure 1). For internal coma testing, the median mesopic pupil size was 4.74 ± 1.37 mm in the FLACS group and 4.99 ± 1.24 mm in the manual cataract surgery group (P = .30). For the primary endpoint, the proportion of eyes reaching the threshold of internal coma less than 0.32 µm was significantly higher following FLACS (54 of 57 eyes [94.7%]) relative to manual cataract surgery (39 of 50 eyes [78.0%]) (OR = 5.08, 95% CI = 1.24 to 20.85, P = .024) (Table 2). When analyzing the data based on the threshold of internal coma less than 0.20 µm, there was no significant difference between groups (FLACS = 48 of 57 eyes [84.2%], manual cataract surgery = 34 of 50 eyes [68.0%], OR = 2.42, 95% CI = 0.82 to 7.15, P = .11). As a continuous outcome, FLACS produced significantly lower values of internal coma relative to manual cataract surgery (Wilcoxon [medians]: FLACS = 0.10 µm, manual cataract surgery = 0.12 µm, P = .005; GEE [mean ± SD]: FLACS = 0.12 ± 0.12 µm, manual cataract surgery = 0.28 ± 0.41 µm, MD = −0.15 µm, 95% CI = −0.30 to −0.006, P = .041) (Table 2). Of the eyes with internal coma of 0.32 µm or greater, median coma was higher following manual cataract surgery (0.46 µm) relative to FLACS (0.36 µm), but no statistical analysis was performed due to low event rates.

Histogram of distribution of internal coma data. FLACS = femtosecond laser–assisted cataract surgery; MCS = manual cataract surgery

Figure 1.

Histogram of distribution of internal coma data. FLACS = femtosecond laser–assisted cataract surgery; MCS = manual cataract surgery

Association Between Clinical Parameters and Internal Coma

Table 2:

Association Between Clinical Parameters and Internal Coma

When the overall analysis was restricted to mesopic pupil sizes only over 5 mm, there was a significantly greater proportion of eyes reaching internal coma less than 0.32 µm following FLACS relative to manual cataract surgery (FLACS = 19 of 22 eyes [86.4%], manual cataract surgery = 12 of 22 eyes [54.5%], OR = 5.28, 95% CI = 1.21 to 23.06, P = .027) (Figure 2). There was no significant difference between groups for the proportion reaching internal coma less than 0.20 µm (P = .32) and continuous internal coma (P = .096).

Scatterplot of the relation between mesopic pupil size and internal coma. FLACS = femtosecond laser–assisted cataract surgery; MCS = manual cataract surgery

Figure 2.

Scatterplot of the relation between mesopic pupil size and internal coma. FLACS = femtosecond laser–assisted cataract surgery; MCS = manual cataract surgery

Characteristics Associated With Improved Internal Coma

Overall, a mesopic pupil size of 5 mm or greater was significantly associated with the proportion of eyes reaching internal coma less than 0.32 µm (P = .002), less than 0.20 µm (P < .001), and as a continuous variable (P = .01) (Table 2). A third-order polynomial relationship between these two parameters revealed high coefficients of determination for both FLACS (R2 = 0.63) and manual cataract surgery (R2 = 0.70), with the average internal coma increasing by a greater amount for every increase in mesopic pupil size greater than 5.75 mm in manual cataract surgery relative to FLACS (Figure 2). Otherwise, there was no significant association between the proportion of eyes reaching internal coma less than 0.32 µm and age of 65 years or younger (P = .23), gender (P = .91), IOL model (P = .42), average keratometry of 44.00 D or less (P = .63), and postoperative cylinder of 0.25 D or less (P = .12). Similar results were observed for eyes with internal coma less than 0.20 µm and internal coma as a continuous variable.

Trefoil, Angle Alpha, and Patient-Reported Quality of Vision

All eyes were included in the trefoil and angle alpha analyses. FLACS was associated with a significantly lower trefoil compared to manual cataract surgery (Wilcoxon [medians]: FLACS = 0.13, manual cataract surgery = 0.22, P = .005; GEE [mean ± SD]: FLACS = 0.17 ± 0.12, manual cataract surgery = 0.26 ± 0.22, MD = −0.089, 95% CI = −0.16 to −0.021, P = .01). There was no significant difference between treatment comparators for angle alpha (Wilcoxon [medians]: FLACS = 0.52, manual cataract surgery = 0.47, P = .37; GEE [mean ± SD]: FLACS = 0.49 ± 0.15, manual cataract surgery = 0.45 ± 0.23, MD = 0.037, 95% CI = −0.056 to 0.130, P = .43).

There was no significant difference between FLACS and manual cataract surgery in terms of patient-reported quality of vision (Wilcoxon [medians]: FLACS = 19, n = 46; manual cataract surgery = 22, n = 43, P = .23; GEE [mean ± SD]: FLACS = 18.8 ± 9.3, manual cataract surgery = 21.2 ± 10.7, MD = −2.4, 95% CI = −7.9 to 3.2, P = .40). There were significantly improved patient satisfaction scores in eyes with internal coma less than 0.32 µm relative to those with coma 0.32 µm or greater (Wilcoxon [medians]: < 0.32 µm: 18.5, n = 76, ≥ 0.32 µm: 27.0, n = 13, P = .008; GEE [mean ± SD]: < 0.32 µm: 18.8 ± 9.6, ≥ 0.32 µm: 27.2 ± 9.3, MD = 8.5, 95% CI = 2.0 to 15.0; P = .01). The same conclusion was reached when considering internal coma less than 0.20 µm as a parameter (Wilcoxon [medians]: < 0.20 µm: 16.0, n = 67, ≥ 0.20 µm: 26.0, n = 22, P = .001; GEE [mean ± SD]: < 0.20 µm: 17.8 ± 9.7, ≥ 0.20 µm: 26.6 ± 8.0, MD = 8.8, 95% CI = 3.5 to 14.0; P = .001). All eyes (n = 15) with patient satisfaction scores of 0 to 10 had internal coma less than 0.20 µm, compared to those with scores of 11 to 20 (27 of 29 eyes, 93.1%), 21 to 30 (19 of 30 eyes, 63.3%), and greater than 30 (8 of 15 eyes, 53.3%) (P value range: .001 to .02 depending on analysis; Table 3; Figure 3). When examining associations between demographic and clinical factors with patient satisfaction scores, the only statistically significant relationship found was for gender (satisfaction score < 20: P = .02, satisfaction score continuous variable: P = .01) (Table 3).

Association Between Clinical Parameters and Patient Satisfaction Scores

Table 3:

Association Between Clinical Parameters and Patient Satisfaction Scores

Scatterplot of the relation between internal coma and patient-reported satisfaction scores. FLACS = femtosecond laser– assisted cataract surgery; MCS = manual cataract surgery

Figure 3.

Scatterplot of the relation between internal coma and patient-reported satisfaction scores. FLACS = femtosecond laser– assisted cataract surgery; MCS = manual cataract surgery

Discussion

In our analysis, FLACS was found to have a significantly lower associated internal coma and trefoil compared to manual cataract surgery. There appears to be a greater consistency in the ability of FLACS to produce symmetrical overlap of the anterior capsule on the optic, which lowers HOAs such as internal coma14 (Figure A, available in the online version of this article). In addition, there were more than four times the proportion of eyes not reaching internal coma less than 0.32 µm from the manual cataract surgery cohort (11 eyes, 22.0%) relative to FLACS (3 eyes, 5.3%) (Figure 1; P = .024). However, the same conclusion was not reached when using less than 0.20 µm as a threshold. It is important to note that no significant difference in mesopic pupil size existed between treatment comparators. Future studies should clarify the degree of the correlation between the extent of internal coma and the symmetry of overlap between the anterior capsule and the optic.

(A) Slit-lamp examination demonstrating symmetrical overlap of the anterior capsule on the optic in a patient with low postoperative internal coma. (B) Split anterior capsule after femtosecond laser–assisted cataract surgery with associated high postoperative internal coma.

Figure A.

(A) Slit-lamp examination demonstrating symmetrical overlap of the anterior capsule on the optic in a patient with low postoperative internal coma. (B) Split anterior capsule after femtosecond laser–assisted cataract surgery with associated high postoperative internal coma.

Asymmetrical overlap of the anterior capsule on the optic leads to internal coma, which is manifested more significantly under mesopic conditions as the pupil size increases. On average, at a mesopic pupil size of greater than 5.75 mm, there was a greater increase in internal coma following manual cataract surgery relative to FLACS for every increase in pupil size. The difference in average coma between FLACS and manual cataract surgery became larger the greater the pupil size was for any pupil size greater than 5.75 mm (Figure 2). These principles are exemplified in one case from our series, in which the right eye from a 67-year-old patient sustained a split anterior capsule following FLACS. Despite a centered IOL, the postoperative internal coma was 0.728 with a large 6.72-mm mesopic pupil, which was attributable to unequal forces.

Past work has demonstrated a positive correlation between vertical coma and vertical tilt, which may be attributable to IOL decentration.3,15 Indeed, a 2016 meta-analysis by our team showed that FLACS had a significantly improved horizontal IOL centration relative to manual cataract surgery.7 In general, internal coma affects the quality of vision under mesopic conditions, especially with multifocal lenses.

In reviewing the literature on FLACS, there is little published information on other measures of visual quality. Miháltz et al.3 performed an analysis of 99 eyes in 2011 that showed a significantly lower average intraocular vertical tilt (−0.05 ± 0.36 vs 0.27 ± 0.57) and coma (−0.003 ± 0.11 vs 0.1 ± 0.15), as well as higher mean Strehl ratio (0.02 ± 0.02 vs 0.01 ± 0.01) and modulation transfer function at all measured cycles per degree after FLACS relative to manual cataract surgery. There were no differences in ocular aberrometry parameters 6 months postoperatively, but there was a significant reduction in intraocular vertical tilt and coma following FLACS. There were no differences between comparators in postoperative uncorrected or corrected distance visual acuity, sphere, or cylinder.

Although it is known that internal aberrations may originate from either the lens or the posterior corneal surface, it is not currently possible to differentiate between these sources with the NIDEK OPD-Scan aberrometer. Nonetheless, Dubbelman et al.16 showed that the posterior surface of the cornea compensates for approximately 3.5% of the anterior surface coma and that the anterior corneal surface and crystalline lens are the only two factors influencing the coma aberration of the whole eye.

The quality of postoperative vision analysis showed that there was no significant difference in patient-reported vision quality when comparing FLACS to manual cataract surgery. Interestingly, lower internal coma following FLACS did not translate to better patient-reported satisfaction with vision. Nonetheless, three observations were made: (1) at internal coma ranging from 0 to 0.2 µm, satisfaction scores varied considerably (range: 0 to 38), (2) at internal coma between 0.2 to 0.4 µm, satisfaction scores were consistently greater than 10, and (3) at internal coma greater than 0.4 µm, satisfaction scores were consistently greater than 20 (Figure 3). This supports the notion that at lower internal coma scores, patient satisfaction was improved but fairly variable, whereas at higher internal coma, no patient reported excellent satisfaction. Even within the group of patients with normal internal coma (ie, < 0.32 µm), patients with lower internal coma experienced an improvement in their own perceived quality of vision, which was confirmed on GEE testing. Our analysis of the data suggests that internal coma of 0.20 µm is the threshold that typically separates excellent from good satisfaction scores. Nonetheless, patient satisfaction scores are not only a function of the procedure performed, but also the expectations of each individual patient.

Despite being one of the first analyses investigating HOA outcomes following FLACS, this study is limited by the potential for selection bias and confounding in the findings. Although this study was not randomized, there was no significant difference in internal coma based on baseline parameters such as age, gender, IOL model, average keratometry, or postoperative cylinder. As expected, there was a significant association between internal coma and mesopic pupil size (Figure 2).

Two different IOLs were implanted in this study. However, the IOL model was found not to have a significant association with internal coma (Table 2) or patient satisfaction (Table 3). A subgroup analysis limited to patients who received the TECNIS Symfony IOL showed similar differences between FLACS and manual cataract surgery as outlined in the overall analysis. Prior work by Kim et al.17 compared HOAs in 42 eyes receiving implantation of monofocal (SI40NB, silicone 3 piece; Johnson and Johnson Vision) and multifocal IOLs (zonal-progressive Array SA40N, silicone 3 piece, Johnson and Johnson Vision). In the multifocal cohort, HOAs were also measured with the addition of a −0.50 D trial lens, which allowed for the assessment of the compensatory effect on spherical aberration. In photopic conditions (pupil size: 4 mm), coma aberration was 0.15 ± 0.08 µm in the monofocal group and 0.19 ± 0.10 µm in the multifocal group (P = .059). Coma was 0.24 ± 0.15 µm in the multifocal with −0.50 D group (P < .05 for both comparisons). There was no difference between groups for trefoil.

This study supports the hypothesis that FLACS produces statistically significant improvements in HOAs relative to manual cataract surgery. There are more than four times the proportion of eyes not reaching internal coma less than 0.32 µm following manual cataract surgery compared to FLACS. Eyes with excellent patient-reported satisfaction all had internal coma less than 0.20 µm. Further research is needed to clarify whether the same conclusions hold true in a more controlled setting.

References

  1. Soong HK, Malta JB. Femtosecond lasers in ophthalmology. Am J Ophthalmol. 2009;147:189–197. doi:10.1016/j.ajo.2008.08.026 [CrossRef]
  2. Kránitz K, Miháltz K, Sándor GL, et al. Intraocular lens tilt and decentration measured by Scheimpflug camera following manual or femtosecond laser-created continuous circular capsulotomy. J Refract Surg. 2012;28:259–263. doi:10.3928/1081597X-20120309-01 [CrossRef]
  3. Miháltz K, Knorz MC, Alió JL, et al. Internal aberrations and optical quality after femtosecond laser anterior capsulotomy in cataract surgery. J Refract Surg. 2011;27:711–716. doi:10.3928/1081597X-20110913-01 [CrossRef]
  4. Kránitz K, Takacs A, Miháltz K, et al. Femtosecond laser capsulotomy and manual continuous curvilinear capsulorrhexis parameters and their effects on intraocular lens centration. J Refract Surg. 2011;27:558–563. doi:10.3928/1081597X-20110623-03 [CrossRef]
  5. Palanker DV, Blumenkranz MS, Andersen D, et al. Femtosecond laser-assisted cataract surgery with integrated optical coherence tomography. Sci Transl Med. 2010;2:58ra85. doi:10.1126/scitranslmed.3001305 [CrossRef]
  6. Friedman NJ, Palanker DV, Schuele G, et al. Femtosecond laser capsulotomy. J Cataract Refract Surg. 2011;37:1189–1198. doi:10.1016/j.jcrs.2011.04.022 [CrossRef]
  7. Popovic M, Campos-Moller X, Schlenker MB, Ahmed II. Efficacy and safety of femtosecond laser-assisted cataract surgery compared with manual cataract surgery: a meta-analysis of 14,567 eyes. Ophthalmology. 2016;123:2113–2126. doi:10.1016/j.ophtha.2016.07.005 [CrossRef]
  8. Baumeister M, Bühren J, Kohnen T. Tilt and decentration of spherical and aspheric intraocular lenses: effect on higher-order aberrations. J Cataract Refract Surg. 2009;35:1006–1012. doi:10.1016/j.jcrs.2009.01.023 [CrossRef]
  9. Mester U, Sauer T, Kaymak H. Decentration and tilt of a single-piece aspheric intraocular lens compared with the lens position in young phakic eyes. J Cataract Refract Surg. 2009;35:485–490. doi:10.1016/j.jcrs.2008.09.028 [CrossRef]
  10. Pieh S, Fiala W, Malz A, Stork W. In vitro Strehl ratios with spherical, aberration-free, average, and customized spherical aberration-correcting intraocular lenses. Invest Ophthalmol Vis Sci. 2009;50:1264–1270. doi:10.1167/iovs.08-2187 [CrossRef]
  11. Rohart C, Lemarinel B, Thanh HX, Gatinel D. Ocular aberrations after cataract surgery with hydrophobic and hydrophilic acrylic intraocular lenses: comparative study. J Cataract Refract Surg. 2006;32:1201–1205. doi:10.1016/j.jcrs.2006.01.099 [CrossRef]
  12. McAlinden C, Pesudovs K, Moore JE. The development of an instrument to measure quality of vision: the Quality of Vision (QoV) questionnaire. Invest Ophthalmol Vis Sci. 2010;51:5537–5545. doi:10.1167/iovs.10-5341 [CrossRef]
  13. Aly MG, Hamza I, Hashem KAMultifocal IOL dissatisfaction in patients with high coma aberration. Presented at the ASCRS Symposium on Cataract, IOL, and Refractive Surgery. ; March 2011. ; San Diego, CA. .
  14. Rapuano CJ. Section 13: refractive surgery. Basic and Clinical Science Course. San Francisco: American Academy of Ophthalmology; 2012:7–9.
  15. Thibos LN, Hong X, Bradley A, Cheng X. Statistical variation of aberration structure and image quality in a normal population of healthy eyes. J Opt Soc Am A Opt Image Sci Vis. 2002;19:2329–2348. doi:10.1364/JOSAA.19.002329 [CrossRef]
  16. Dubbelman M, Sicam VA, van der Heijde RG. The contribution of the posterior surface to the coma aberration of the human cornea. J Vis. 2007;7:10.1–8.
  17. Kim CY, Chung SH, Kim TI, Cho YJ, Yoon G, Seo KY. Comparison of higher-order aberration and contrast sensitivity in monofocal and multifocal intraocular lenses. Yonsei Med J. 2007;48:627–633. doi:10.3349/ymj.2007.48.4.627 [CrossRef]

Demographic Data Stratified by Treatment

ParameterFLACSManual Cataract Surgery
No. of eyes5750
Age (y; median ± IQR)66.0 ± 6.368.5 ± 7.8
Gender (% female)35 (61.4%)32 (64.0%)
Laterality (% right eyes)25 (43.9%)25 (50.0%)
Preoperative keratometry (D; median ± IQR)44.06 ± 1.7543.75 ± 1.50
Postoperative mesopic pupil size (mm; median ± IQR)4.74 ± 1.374.99 ± 1.24
Postoperative spherical equivalent (D; median ± IQR)0.00 ± 0.500.00 ± 0.38
Postoperative cylinder (D; median ± IQR)0.50 ± 0.500.50 ± 0.25
Postoperative corrected distance visual acuity (logMAR; median ± IQR)0.00 ± 0.000.00 ± 0.00

Association Between Clinical Parameters and Internal Coma

ParameterInternal Coma < 0.32 µmInternal Coma < 0.20 µmInternal Coma – Continuous Variable



OR95% CIPOR95% CIPMD (µm)95% CIP
FLACS5.081.24 to 20.85.0242.420.82 to 7.15.11−0.15−0.30 to −0.006.041
Age ≤ 65 y2.310.59 to 9.09.232.450.85 to 7.11.100.11−0.05 to 0.28.18
Gender1.090.27 to 4.35.911.580.49 to 5.10.440.009−0.14 to 0.16.91
Average keratometry ≤ 44.00 D1.410.35 to 5.67.631.100.41 to 2.97.85−0.042−0.18 to 0.091.54
Postoperative cylinder ≤ 0.25 D2.580.79 to 8.39.122.070.81 to 5.31.130.055−0.038 to 0.148.25
IOL model2.700.25 to 29.28.421.350.26 to 7.16.720.021−0.056 to 0.099.59
Mesopic pupil size ≤ 5 mm26.003.23 to 209.47.0026.672.41 to 18.42< .001−0.200−0.353 to −0.047.01

Association Between Clinical Parameters and Patient Satisfaction Scores

ParameterPatient Satisfaction Score < 20Patient Satisfaction Score – Continuous Variable


OR95% CIPMD95% CIP
Treatment1.500.48 to 4.77.49−2.36−7.91 to 3.19.40
Internal coma < 0.32 µm6.791.33 to 34.61.028.481.98 to 14.99.01
Internal coma < 0.20 µm9.991.89 to 52.70.0078.773.54 to 13.99.001
Age ≤ 65 y1.390.42 to 4.56.59−2.34−7.61 to 2.92.38
Gender4.611.28 to 16.63.026.861.66 to 12.05.01
Average keratometry ≤ 44.00 D1.500.51 to 4.37.461.89−3.07 to 6.84.46
Postoperative cylinder ≤ 0.25 D1.990.79 to 4.97.14−2.22−6.57 to 2.14.32
IOL model2.070.41 to 10.36.38−1.80−8.63 to 5.03.61
Mesopic pupil size ≤ 5 mm2.730.89 to 8.32.082.89−2.55 to 8.33.30
Authors

From the Specialty Eye Institute, Jackson, Michigan (PHE, LK); the Faculty of Medicine (MP) and the Department of Ophthalmology of Vision Sciences (MBS, IIKA), University of Toronto, Toronto, Ontario, Canada; and the Prism Eye Institute and the Department of Ophthalmology, Trillium Health Partners, Mississauga, Ontario, Canada (IIKA).

Dr. Ahmed is a consultant for Alcon, Johnson & Johnson Vision, Bausch & Lomb, Inc., and Carl Zeiss AG. Dr. Schlenker is a consultant for Alcon, Johnson & Johnson Vision, Allergan, and Light Matter Interaction. The remaining authors have no financial or proprietary interest in the materials presented herein.

AUTHOR CONTRIBUTIONS

Study concept and design (PHE, MP, MBS, LK, IIKA); data collection (PHE, MP, LK); analysis and interpretation of data (PHE, MP, MBS); writing the manuscript (PHE, MP); critical revision of the manuscript (PHE, MP, MBS, LK, IIKA); statistical expertise (MP, MBS, IIKA); administrative, technical, or material support (PHE, LK, IIKA); supervision (PHE, MBS, LK, IIKA)

Correspondence: Paul H. Ernest, MD, Specialty Eye Institute, 1116 W. Ganson, Jackson, MI 49202. E-mail: pernest@specialtyeyeinstitute.com

Received: July 23, 2018
Accepted: January 02, 2019

10.3928/1081597X-20190107-02

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