Rethinking presbyopia: results of bilateral refractive lens exchange with trifocal intraocular lenses in 17 603 patients.

PURPOSE: To evaluate the safety and effectiveness of bilateral refractive lens exchange (RLE) with trifocal intraocular lens (IOL) as the surgical treatment of presbyopia. SETTINGS: Memira AS. Norway, Sweden and Denmark. DESIGN: Multicentric retrospective interventional case series. METHODS: 17 603 consecutive patients submitted to bilateral presbyopic RLE with trifocal IOLs from 2013 to 2019. The main outcomes were manifest refraction spherical equivalent (MRSE), uncorrected distance (UDVA) and near (UNVA) visual acuity, corrected distance visual acuity (CDVA), vision gain/loss, safety and efficacy indices, IOL power calculation accuracy and rate of excimer laser enhancements. RESULTS: Three months postoperatively, the mean MRSE was 0.00±0.40 diopters (D), mean binocular UDVA was -0.03±0.09, with 14 470 patients (82.2%) with combined binocular UDVA and UNVA equal or better than 0.00 and Jaeger 3. Approximately 86% (n=30.124) of the eyes were within 0.50D of MRSE. Enhancement surgery was performed in 5810 eyes (16.5%). IOL power calculation refining improved accuracy and reduced enhancements rate from 20% in 2013 to 12% in 2019. Safety and efficacy indices were 0.98±0.11 and 0.85±0.18, respectively. Myopic eyes presented significant higher safety (1.00±0.19) and efficacy indices (0.87±0.19), with p<0.005. Approximately 0.38% (n=130) of the eyes lost two or more lines of CDVA, with cystoid macular oedema (n=53, 40.8%) and posterior capsular opacification (n=35, 26.9%) as the main causes. After proper care, the final incidence of two or more lines of vision loss was 0.08% (28 eyes). CONCLUSIONS: Presbyopic RLE with trifocal IOL is a safe and effective modality of treatment for patients with presbyopia.

The PEARL-DGS Formula: The Development of an Open-source Machine Learning-based Thick IOL Calculation Formula.

PURPOSE: To describe an open-source, reproducible, step-by-step method to design sum-of-segments thick intraocular lens (IOL) calculation formulas, and to evaluate a formula built using this methodology. DESIGN: Retrospective, multicenter case series METHODS: A set of 4242 eyes implanted with Finevision IOLs (PhysIOL, Liège, Belgium) was used to devise the formula design process and build the formula. A different set of 677 eyes from the same center was kept separate to serve as a test set. The resulting formula was evaluated on the test set as well as another independent data set of 262 eyes. RESULTS: The lowest standard deviation (SD) of prediction errors on Set 1 were obtained with the PEARL-DGS formula (±0.382 D), followed by K6 and Olsen (±0.394 D), EVO 2.0 (±0.398 D), RBF 3.0, and BUII (±0.402 D). The formula yielding the lowest SD on Set 2 was the PEARL-DGS (±0.269 D), followed by Olsen (±0.272 D), K6 (±0.276 D), EVO 2.0 (±0.277 D), and BUII (±0.301 D). CONCLUSION: Our methodology achieved an accuracy comparable to other state-of-the-art IOL formulas. The open-source tools provided in this article could allow other researchers to reproduce our results using their own data sets, with other IOL models, population settings, biometric devices, and measured, rather than calculated, posterior corneal radius of curvature or sum-of-segments axial lengths.

Presbyopic refractive lens exchange with trifocal intraocular lens implantation after corneal laser vision correction: Refractive results and biometry analysis.

PURPOSE: To evaluate the refractive and biometry results of presbyopic refractive lens exchange (RLE) with trifocal intraocular lens (IOL) implantation in eyes with previous myopic or hyperopic corneal laser vision correction (LVC). SETTINGS: Memira AS, Norway, Sweden, and Denmark. DESIGN: Retrospective case series. METHODS: The refractive results included the manifest refraction spherical equivalent, uncorrected near (UNVA) and distance (UDVA) visual acuities, corrected distance visual acuity, safety, efficacy, and precision. The biometry analysis included the refractive prediction error (RPE), median absolute error (MedAE), and percentage of eyes within a certain RPE range for the formulas from the American Society of Cataract and Refractive Surgery (ASCRS) online calculator. RESULTS: The study comprised 241 eyes. Six months postoperatively, 60.0% of eyes were within ±0.25 diopter (D), 80.9% within ±0.50 D, and 97.9% within ±1.00 D of emmetropia. There were no statistical differences in the mean monocular UDVA (0.87 ± 0.20 [SD]), safety index (0.98 ± 0.09), or efficacy index (0.81 ± 0.18) between the myopic ablation group and hyperopic ablation group. Binocularly, 85% of patients had simultaneous UDVA and UNVA of 0.9 or better and Jaeger 3, respectively. The ASCRS online calculator formulas gave different performances for previous myopic and hyperopic ablation profiles. Using optimized constants and nomogram for correcting the mean RPE improved the MedAE. CONCLUSIONS: Presbyopic RLE was safe and effective in selected cases with a history of LVC. The use of optimized IOL constants and nomograms can improve the refractive precision of lens-based refractive surgery.

Myopic Surface Ablation in Asymmetrical Topographies: Refractive Results and Theoretical Corneal Elastic Response.

PURPOSE: To evaluate refractive results and the theoretical elastic response of photorefractive keratectomy in eyes with asymmetrical corneal surface and to compare such outcomes with a control-matched group of normal topographies. DESIGN: Retrospective interventional case series with matched comparison group. METHODS: Thirty eyes with superior-inferior dioptric difference (SI index) > 1.40 diopter (D) were compared to 30 eyes with normal topographies. Both groups were matched for age, preoperative spherical equivalent (SE), mean keratometry, and percentage of tissue altered (PTA). Refractive results and the theoretical elastic modulus calculations were evaluated. RESULTS: The mean preoperative SI index in the asymmetrical group was 2.06 ± 0.56 D vs 0.14 ± 0.73 D in the control group (P < .001). From 3 to 12 months postoperatively, the asymmetrical group presented a mean re-steepening of 0.51 ± 0.39 D vs 0.19 ± 0.40 D in the control group (P = .014). The mean PTA of 14.42% generated a theoretical elastic modulus reduction of 10.25% in the asymmetrical group vs 2.45% in the control group (P = .006). The reduction of the theoretical elastic modulus correlated with the preoperative SI index (ρ = -0.387, P = .007). After 36 months, 90% of all eyes were within ±0.50 D of SE and the theoretical elastic modulus did not present a significant difference between both groups (P = .085). CONCLUSIONS: Asymmetrical-topography corneas treated with myopic surface ablation presented an increased short-term keratometric re-steepening and reduction of the theoretical elastic moduli. The long-term follow-up indicated that, in selected cases of asymmetrical topographies, myopic surface ablation could induce a premature biomechanical elastic response rather than a progressive pathologic process.

Corneal higher-order aberrations and higher-order Strehl ratio after aberration-free ablation profile to treat compound myopic astigmatism.

PURPOSE: To evaluate the changes in corneal higher-order aberrations (HOAs) and their impact on corneal higher-order Strehl ratio after aberration-free ablation profile. SETTING: Verter Institute, H. Olhos, São Paulo, Brazil. DESIGN: Prospective interventional study. METHODS: Eyes that had aberration-free myopic ablation were divided into 3 groups, based on the spherical equivalent (SE). The corneal HOAs and higher-order Strehl ratios were calculated before surgery and 3 months after surgery. RESULTS: The postoperative uncorrected-distance visual acuity, corrected-distance visual acuity, and SE did not present statistical differences among groups (88 eyes, P > .05). For a 6 mm pupil, the corneal HOA showed a mean increase of 0.17 µm (range 0.39 to 0.56 µm) (P < .001) and the corneal higher-order Strehl ratio presented a reduction of 0.03 (from 0.25 to 0.22) (P = .001). The following consistent linear predictive model was obtained: corneal HOA induction = 1.474 - 0.032 × SE - 0.225 × OZ, where OZ is the optical zone (R(2) = 0.49, adjusted R(2) = 0.48, P < .001). CONCLUSIONS: The corneal HOAs and the higher-order Strehl ratios deteriorated after moderate and high myopic ablations. The worsening in corneal aberrations and optical quality were related to the magnitude of the intended correction and did not affect high-contrast visual performance. The OZ was the only modifiable parameter capable to restrain the optical quality loss. FINANCIAL DISCLOSURE: The author has no financial or proprietary interest in any material or method mentioned.

Laser in situ keratomileusis using optimized aspheric profiles and cyclotorsion control to treat compound myopic astigmatism with high cylinder.

PURPOSE: To evaluate the visual outcomes after laser in situ keratomileusis (LASIK) surgery to correct primary compound myopic astigmatism with high cylinder performed using a fast-repetition-rate excimer laser platform with optimized aspheric profiles and cyclotorsion control. SETTING: Vissum Corporation and Division of Ophthalmology, Universidad Miguel Hernández, Alicante, Spain. DESIGN: Retrospective consecutive observational nonrandomized noncomparative case series. METHODS: Eyes with primary compound myopic astigmatism and a cylinder power over 3.00 diopters (D) had uneventful LASIK with femtosecond flap creation and fast-repetition-rate excimer laser ablation with aspheric profiles and cyclotorsion control. Visual, refractive, and aberrometric outcomes were evaluated at the 6-month follow-up. The astigmatic correction was evaluated using the Alpins method and Assort software. RESULTS: The study enrolled 37 eyes (29 patients; age range 19 to 55 years). The significant reduction in refractive sphere and cylinder 3 months and 6 months postoperatively (P<.01) was associated with improved uncorrected distance visual acuity (P<.01). Eighty-seven percent of eyes had a spherical equivalent within ±0.50 D; 7.5% of eyes were retreated. There was no significant induction of higher-order aberrations (HOAs). The targeted and surgically induced astigmatism magnitudes were 3.23 D and 2.96 D, respectively, and the correction index was 0.91. The safety and efficacy indices were 1.05 and 0.95, respectively. CONCLUSIONS: Laser in situ keratomileusis for primary compound myopic astigmatism with high cylinder (>3.00 D) performed using a fast-repetition-rate excimer laser with optimized aspheric profiles and cyclotorsion control was safe, effective, and predictable and did not cause significant induction of HOAs.

Outcomes of intrastromal corneal ring segments for treatment of keratoconus: five-year follow-up analysis.

PURPOSE: To report the long-term refractive and optical quality outcomes of patients with intrastromal corneal ring segments (ICRS) to treat keratoconus and to analyze the results according to the patients' age. SETTING: Vissum Instituto Oftalmologico de Alicante, Alicante, Spain. DESIGN: Case series. METHODS: The uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), manifest refraction, corneal topography, and aberrometry were evaluated before and after ICRS implantation in eyes with keratoconus. The follow-up was 5 years in all cases. RESULTS: The study comprised 51 eyes (35 patients; age range 15 to 56 years). After 6 months, the improvement in the UDVA, CDVA, spherical equivalent, and mean keratometry (K) value was statistically significant (P<.05). Five years postoperatively, these parameters remained unchanged (P=.31). Slight regression (0.97 diopter [D]) was observed in the mean K between 6 months and 5 years; the regression was not statistically significant (P=.39). Anterior corneal aberrometric values decreased; however, the changes were not statistically significant (P ≥.10). Linear regression analysis showed no correlation between the age of the patients and the changes observed in the mean K throughout the follow-up (P>.05, r(2) = 0.001). CONCLUSIONS: Intrastromal corneal ring segment implantation in keratoconus patients provided long-term improvement of the refractive and topographic status. There was no correlation between the amount of individual changes in the mean K reading and patient age.

Outcome analysis of intracorneal ring segments for the treatment of keratoconus based on visual, refractive, and aberrometric impairment.

PURPOSE: To analyze the outcomes of intracorneal ring segment (ICRS) implantation for the treatment of keratoconus based on preoperative visual impairment. DESIGN: Multicenter, retrospective, nonrandomized study. METHODS: A total of 611 eyes of 361 keratoconic patients were evaluated. Subjects were classified according to their preoperative corrected distance visual acuity (CDVA) into 5 different groups: grade I, CDVA of 0.90 or better; grade II, CDVA equal to or better than 0.60 and worse than 0.90; grade III, CDVA equal to or better than 0.40 and worse than 0.60; grade IV, CDVA equal to or better than 0.20 and worse than 0.40; and grade plus, CDVA worse than 0.20. Success and failure indices were defined based on visual, refractive, corneal topographic, and aberrometric data and evaluated in each group 6 months after ICRS implantation. RESULTS: Significant improvement after the procedure was observed regarding uncorrected distance visual acuity in all grades (P < .05). CDVA significantly decreased in grade I (P < .01) but significantly increased in all other grades (P < .05). A total of 37.9% of patients with preoperative CDVA 0.6 or better gained 1 or more lines of CDVA, whereas 82.8% of patients with preoperative CDVA 0.4 or worse gained 1 or more lines of CDVA (P < .01). Spherical equivalent and keratometry readings showed a significant reduction in all grades (P ≤ .02). Corneal higher-order aberrations did not change after the procedure (P ≥ .05). CONCLUSIONS: Based on preoperative visual impairment, ICRS implantation provides significantly better results in patients with a severe form of the disease. A notable loss of CDVA lines can be expected in patients with a milder form of keratoconus.

Clinical grading of post-LASIK ectasia related to visual limitation and predictive factors for vision loss.

PURPOSE: To evaluate and characterize the main clinical features of post-laser in situ keratomileusis (LASIK) ectasia, propose a grading system based on visual limitation, and identify predictive factors related to the degree of visual loss. SETTING: Vissum Corp., Alicante, Spain. DESIGN: Retrospective case series. METHODS: This study comprised consecutive eyes with corneal ectasia after LASIK from 1996 to 2010. Main outcomes were post-LASIK ectasia corrected distance visual acuity (CDVA), CDVA loss, spherical equivalent (SE), and the corneal bulge (delta K). These outcomes were correlated with the residual stromal bed, ablation depth, ablation ratio (ablation depth:pachymetry), corneal depth (flap + ablation depth), and corneal ratio (corneal depth:pachymetry) to characterize their role in the severity of the disease. RESULTS: The mean post-LASIK ectasia CDVA, CDVA loss, SE, and delta K were 0.20 logMAR ± 0.18 (SD), -0.13 ± 0.15 logMAR, -3.80 ± 3.86 diopters (D), and 4.77 ± 4.23 D, respectively. The ablation ratio had the strongest correlation with post-LASIK ectasia CDVA (ρ = 0.477 and P<.001), whereas the corneal ratio had the strongest correlation with the post-LASIK ectasia SE and delta K (ρ = -0.614 and ρ = 0.453, respectively: P<.001). The ablation ratio was the main predictive factor for post-LASIK ectasia CDVA loss (relative risk, 2.04; P=.049). CONCLUSIONS: The grading system based on visual limitation was consistently represented by differences in CDVA loss, SE, and delta K. A high amount of tissue removed by the refractive procedure was associated with greater corneal biomechanical destabilization, increased corneal steepening, and a worse prognosis.

Indications for intrastromal corneal ring segments in ectasia after laser in situ keratomileusis.

PURPOSE: To evaluate clinical results of intrastromal corneal ring segments (ICRS) in a large series of post-laser in situ keratomileusis (LASIK) ectasia and determine which clinical parameters were related to the success of this technique. SETTINGS: Vissum Corporation and Clínica Baviera Group, Alicante, Spain. DESIGN: Case series. METHODS: Intrastromal corneal ring segments were implanted to correct the spherocylindrical error and improve visual acuity. Based on a previously described grading system, the best indications for ICRS implantation to treat post-LASIK ectasia were evaluated. The variables related to favorable outcomes over a 12-month follow-up were determined. RESULTS: Patients who lost 2 or more lines due to post-LASIK ectasia had a mean gain of +2.89 lines of corrected distance visual acuity (CDVA) after ICRS implantation (P<.001) and a mean CDVA of 0.81 (95% confidence interval, 0.74-0.88). In contrast, patients who did not lose vision after ectasia had a mean loss of -2.00 lines of CDVA after the ICRS implantation (P<.001). The odds ratio of a gain of at least 1 line of CDVA was 18 times greater for those who had lost 2 or more lines of CDVA after ectasia. CONCLUSIONS: The best indications for ICRS were a loss of 2 or more lines of CDVA after ectasia and post-LASIK ectasia grade 4. Patients who do not have vision loss after ectasia and those classified as grade 1 should not be considered candidates for ICRS implantation. FINANCIAL DISCLOSURE: No author has a financial or proprietary interest in any material or method mentioned.