Outcomes of the Haigis-L formula for calculating intraocular lens power in Asian eyes after refractive surgery

Intraocular Lens Power Calculation in Eyes After Myopic Laser Refractive Surgery and Radial Keratotomy: Bayesian Network Meta-analysis

PURPOSE

To compare the accuracy of formulas for calculating intraocular lens power in eyes after myopic laser refractive surgery or radial keratotomy.

DESIGN

Bayesian network meta-analysis.

METHODS

PubMed, Embase, the Cochrane Data Base of Systematic Reviews, and the Cochrane Central Register of Controlled Trials databases were searched for retrospective and prospective clinical studies published from January 1, 2012, to August 24, 2022. The outcome measurement was the percentage of eyes with a predicted error within the target refractive range (±0.50 diopter [D] or ±1.00 D).

RESULTS

Our meta-analysis includes 24 studies of 1172 eyes after myopic refractive surgery that use 12 formulas for intraocular lens power calculation. (1) A network meta-analysis showed that Barrett true-K no history, the optical coherence tomography (OCT) formula, and the Masket formula had a significantly higher percent of eyes within ±0.50 D of the goal than the Haigis-L formula, whereas the Wang-Koch-Maloney formula showed the poor predictability. Using an error criterion of within ±1.00 D, the same 3 formulas performed slightly better than the Haigis-L formula. Based on performance using both prediction error criteria, the Barrett true-K no history formula, OCT formula, and Masket formula showed the highest probability of ranking as the top 3 among the 12 methods. (2) A direct meta-analysis with a subset of 4 studies and 5 formulas indicated that formulas did not differ in percent success for either the ±0.5 D or ±1.0 D error range in eyes that had undergone radial keratotomy.

CONCLUSIONS

The OCT, Masket, and Barrett true-K no history formulas are more accurate for eyes with previous myopic laser refractive surgery, whereas no significant difference was found among the formulas for eyes that had undergone radial keratotomy.

An update on intraocular lens power calculations in eyes with previous laser refractive surgery

PURPOSE OF REVIEW

There is an ever-growing body of research regarding intraocular lens (IOL) power calculations following photorefractive keratectomy (PRK), laser-assisted in-situ keratomileusis (LASIK), and small-incision lenticule extraction (SMILE). This review intends to summarize recent data and offer updated recommendations.

RECENT FINDINGS

Postmyopic LASIK/PRK eyes have the best refractive outcomes when multiple methods are averaged, or when Barrett True-K is used. Posthyperopic LASIK/PRK eyes also seem to do best when Barrett True-K is used, but with more variable results. With both aforementioned methods, using measured total corneal power incrementally improves results. For post-SMILE eyes, the first nontheoretical data favors raytracing.

SUMMARY

Refractive outcomes after cataract surgery in eyes with prior laser refractive surgery are less accurate and more variable compared to virgin eyes. Surgeons may simplify their approach to IOL power calculations in postmyopic and posthyperopic LASIK/PRK by using Barrett True-K, and employing measured total corneal power when available. For post-SMILE eyes, ray tracing seems to work well, but lack of accessibility may hamper its adoption.

Comparison of intraocular lens power calculation formulas with and without total keratometry and ray tracing in patients with previous myopic SMILE

PURPOSE

To evaluate the prediction error (PE) variance and absolute median PE of different intraocular lens (IOL) calculation formulas including last-generation formulas such as Barrett True-K with K, Okulix and total keratometry (TK)-based calculations with Haigis, and Barrett True-K in a simulation model in post-small-incision lenticule extraction (SMILE) eyes.

SETTINGS

Department of Ophthalmology, University Hospital Marburg, Marburg, Germany.

DESIGN

Prospective study.

METHODS

Preoperative measurements included IOL power calculation before and after SMILE surgery. The target refraction was set to be the lowest myopic refractive error in pre-SMILE eyes. The IOL power targeting at the lowest myopic refractive error in pre-SMILE eyes was selected for the post-SMILE IOL calculation of the same eye. The difference between the predicted refraction of pre- and post-SMILE eyes with the same IOL power was defined as IOL difference. The refractive change induced by SMILE was defined as the difference between preoperative and postoperative manifest refraction.

RESULTS

98 eyes from 49 patients underwent bilateral myopic SMILE. The PE variance of Okulix was not significantly different compared with Barrett True-K with TK ( P = .471). The SDs of the mean PEs were ±0.413 D (Haigis-TK), ±0.453 D (Okulix), ±0.471 D (Barrett True-K with TK), ±0.556 D (Haigis-L), and ±0.576 D (Barrett True-K with K). The mean absolute PE was 0.340 D, 0.353 D, 0.404 D, 0.511 D, and 0.715 D for Haigis-TK, Okulix, Barrett True-K with TK, Barrett True-K with K, and Haigis-L, respectively. The highest percentage of eyes within ±0.50 D was achieved by Okulix, followed by Haigis-TK, Barrett True-K with TK, Barrett True-K with K, and Haigis-L.

CONCLUSIONS

Results suggest that Haigis in combination with TK, Okulix, and Barrett True-K with and without TK offer good options for accurate IOL power calculation after SMILE. Haigis-L showed a tendency for myopic shift in eyes after previous SMILE.

The influence of corneal ablation patterns on prediction error after cataract surgery in post-myopic-LASIK eyes

Purpose

To evaluate the influence of corneal ablation patterns on the prediction error after cataract surgery in post-myopic-LASIK eyes.

Methods

Eighty-three post-myopic-LASIK eyes of 83 patients that underwent uneventful cataract surgery were retrospectively included. Predicted postoperative spherical equivalence (SE) was calculated for the implanted lens using the Haigis-L and Barrett True-K formula. Prediction error at one month postsurgery was calculated as actual SE minus predicted SE. For each eye, area and decentration of the ablation zone was measured using the tangential curvature map. The associations between prediction errors and corneal ablation patterns were investigated.

Results

The mean prediction error was − 0.83 ± 1.00 D with the Haigis-L formula and − 1.00 ± 0.99 D with the Barrett True-K formula. Prediction error was positively correlated with keratometry (K) value and negatively correlated with ablation zone area using either formula, and negatively correlated with decentration of the ablation zone using the Barrett True-K formula (all P < 0.05). In the K < 37.08 D group, prediction error was negatively correlated with decentration of the ablation zone with both formulas (all P < 0.05). Multivariate analysis showed that with the Haigis-L formula, prediction error was associated with axial length (AL), K value and decentration, and with the Barrett True-K formula, prediction error was associated with AL and decentration (all P < 0.05).

Conclusion

A flatter cornea, larger corneal ablation zone and greater decentration will lead to more myopic prediction error after cataract surgery in post-myopic-LASIK eyes.

Accuracy of Formulas for Intraocular Lens Power Calculation After Myopic Refractive Surgery

PURPOSE

To assess the accuracy of the following intraocular lens (IOL) power formulas: Barrett True-K No History (BTKNH), Emmetropia Verifying Optical 2.0 Post Myopic LASIK/PRK (EVO 2.0), Haigis-L, American Society of Cataract and Refractive Surgery (ASCRS) average, and Shammas, designed for patients who have undergone previous myopic refractive surgery, independent of preexisting clinical history and corneal tomographic measurements.

METHODS

Data from 302 eyes of 302 patients who previously underwent myopic refractive surgery and had cataract surgery done by a single surgeon with only one IOL type inserted were included. The predicted refraction was calculated for each of the formulas and compared with the actual refractive outcome to give the prediction error. Subgroup analysis based on the axial length and mean keratometry was performed.

RESULTS

On the basis of mean absolute prediction error (MAE), the formulas were ranked as follows: Haigis-L (0.61 diopters [D]), ASCRS average (0.63 D), BTKNH (0.67 D), EVO 2.0 (0.68 D), and Shammas (0.69 D). The Haigis-L had a statistically significant lower MAE compared with all formulas (P < .05) except the ASCRS average. Hyperopic mean prediction errors were seen in all formulas for axial lengths of greater than 30 mm or mean keratometry values of 35.00 diopters or less.

CONCLUSIONS

The Haigis-L and the ASCRS average formulas provided the most accurate results in the overall population evaluated in this study. Moreover, according to data observed, it is important to be careful handling very long eyes and very flat corneas because hyperopic refractions could be more common. [J Refract Surg. 2022;38(7):443-449.].

Influence of Posterior Corneal Asphericity On Power Calculation Error After Laser In Situ Keratomileusis or Photorefractive Keratectomy for Myopia

OBJECTIVES

To assess the impact of posterior corneal asphericity on postoperative calculation error using the Haigis-L and the Barrett formulas for eyes after laser in situ keratomileusis or photorefractive keratectomy (PRK).

METHODS

We assessed the mean absolute error (MAE) of two power calculation formulas, Barrett true-K and Haigis-L formulas, in a retrospective analysis of 34 eyes of 34 patients who underwent cataract surgery. We performed a regression analysis between corneal parameters (anterior and posterior Q values, Kmax, K1, and K2) and the MAE of each formula.

RESULTS

In the cohort, 11 eyes were of women and 23 of men. The average age of the study population was 66.5±8.6 years. The mean axial length was 24±4.7 mm, the mean anterior chamber depth was 3.27±0.7 mm, and the mean posterior Q-value was -0.15±0.28. The MAE of Haigis-L and Barrett true-K formulas were 0.72 and 0.68, respectively (P=0.54). The regression analysis showed a statistically significant relationship only between the error in refraction prediction and the posterior Q-value regardless of the formula used. The coefficient of determination was higher for the Barrett true-K formula (r=0.52; R2=0.28; P<0.05), compared with the Haigis-L (r=0.49; R2=0.25; P<0.05).

CONCLUSIONS

Posterior corneal surface asphericity influences the refractive error of calculation using both Haigis-L and Barrett true-K formulas for eyes after a myopic PRK or laser-assisted in situ keratomileusis surgery.

Outcomes of the Haigis-L formula for calculating intraocular lens power in extreme long axis eyes after myopic laser in situ keratomileusis

PURPOSE

To evaluate the accuracy of refractive prediction by the Haigis-L formula compared to four other IOL power calculation formulas in eyes with extremely long axial lengths (AL > 29.0 mm) after LASIK.

SETTING

Shanghai Eye Disease and Prevention Treatment Center, Shanghai, China.

DESIGN

Retrospective case series.

METHODS

Twenty-nine eyes from 19 patients were available for analysis. The primary outcome measure was the arithmetic refractive prediction error (RPE), defined as the difference between the actual postoperative refractive error and the intended formula-derived refractive target. The main outcome measure was the median absolute refraction prediction error (MedAE). The accuracy of the Haigis-L was compared with Barrett True K No History, Shammas-PL, SRK/Tcorrected K, and Holladay 2corrected K methods to calculate IOL power.

RESULTS

The Haigis-L formula had a significantly larger MedAE than Shammas-PL and SRK/Tcorrected K formulas (P = 0.005 and P = 0.015, respectively), a smaller percentage of eyes within ±1.50 diopter (D) of predicted error in refraction compared with Shammas-PL and SRK/Tcorrected K formulas (P = 0.014 and P = 0.005, respectively). The refractive prediction errors of 6 eyes with corneal keratometry of less than 35 D by Haigis-L all had more than 1.95 D of myopic overestimation, while none of the other four methods resulted in an absolute error over 1.95 D.

CONCLUSIONS

The Haigis-L formula was relatively accurate in predicting extreme long axis (>29.0 mm) eyes after myopic LASIK surgery but less accurate for eyes with extremely flat corneas (<35 D). SRK/Tcorrected K and Shammas-PL performed better than the other methods for refractive prediction in this type of eyes.

SYNOPSIS

Haigis-L performed worse than SRK/Tcorrected K and Shammas-PL in predicting IOL power in extremely long axis (>29.0 mm) eyes after myopic LASIK, especially with extremely flat corneas (K < 35 D).

Prediction accuracy of No History IOL formulas for a diffractive extended depth-of-focus IOL after myopic corneal refractive surgery

Purpose

To compare the accuracy of intraocular lens (IOL) calculation methods for extended depth-of-focus (EDOF) IOLs in eyes with a history of myopic LASIK/PRK surgery lacking historical data.

Setting

Changsha Aier Eye Hospital, Changsha, and Wuhan Aier Eye Hospital, Wuhan, China.

Design

Retrospective case series.

Methods

Patients with ALs >= 25.0 mm and a history of myopic LASIK/PRK surgery who underwent cataract surgery with implantation of EDOF IOLs were enrolled. A comparison was performed of the accuracy of 10 IOL methods lacking historical data, including Barrett True-K No History (Barrett TKNH), Haigis-L, Shammas, Potvin-Hill, "Average", 'minimum" and "maximum" IOL power on the ASCRS online post-refractive IOL calculator; Triple-S formula; and SToP formulas based on Holladay1 and SRK/T. IOL power was calculated with the abovementioned methods in 2 groups according to AL (Group1: 25.0 mm <= AL < 28.0 mm and Group2: AL >= 28.0 mm).

Results

Sixty-four eyes were included. Excellent outcomes were achieved with the "Minimum", Barrett TKNH, SToP (SRK/T) and Triple-S in the whole sample and subgroups, which led to similar median absolute error, mean absolute error, and the percentage of eyes with a prediction error within +/- 0.5 D. In the whole sample, the Haigis-L and "Maximum" had a significantly higher absolute error than "Minimum", SToP (SRK/T) and Barrett TKNH. The "Maximum" also had a significantly lower percentage of eyes within +/- 0.5 D than the Barrett TKNH, and SToP (SRK/T) (15.6% vs 50% and 51.5%, all P<0.05 with Bonferroni correction).

Conclusions

No-history IOL formulas in predicting the EDOF IOL power in post-myopic refractive eyes remain challenging. The Barrett TKNH, Triple-S, "Minimum" and SToP (SRK/T) achieved the best accuracy when AL >= 25.0 mm, while the Barrett TKNH and SToP (SRK/T) were recommended when AL >= 28.0mm.

Comparison of intraocular lens power formulas according to axial length after myopic corneal laser refractive surgery

PURPOSE

To assess the predictive accuracy of 4 no-history intraocular lens (IOL) power formulas in eyes with prior myopic excimer laser surgery, classified in 4 groups according to their axial length (AL), and investigate the relationship between AL and predictive accuracy.

SETTING

Seoul St. Mary's Hospital, Republic of Korea.

DESIGN

Retrospective case series.

METHODS

IOL power was calculated with the Barrett True-K, Haigis-L, Shammas-PL, and Triple-S formulas in 4 groups classified according to AL. Primary outcomes were the median absolute error (MedAE) and percentage of eyes with a prediction error (PE) within ±0.50 diopter (D).

RESULTS

This study included 107 eyes of 107 patients. The Barrett True-K had the lowest MedAE when AL was <26.0 mm (0.30 D) and between 26.0 and 28.0 mm (0.54 D); in these subgroups, it had the highest percentages with a PE within ±0.50 D (71.4% and 46.2%). For AL between 28.0 and 30.0 mm, the Triple-S method showed the lowest MedAE (0.43 D) and highest percentage with a PE within ±0.50 D (58.3%). For AL ≥30.0 mm, the Shammas-PL formula produced the lowest MedAE (0.41 D) and highest percentage with a PE within ±0.50 D (58.3%). The Barrett True-K was the only formula with a correlation between AL and PE (r = -0.219/P = .023).

CONCLUSIONS

The predictive accuracy of no-history IOL formulas depends on the AL. The Barrett True-K had the highest accuracy when AL was < 28.0 mm and the Triple-S when it ranged from 28.0 mm to 30.0 mm, whereas the Shammas-PL was more accurate when AL was ≥30.0 mm.

Color light-emitting diode reflection topography: Validation of Equivalent K Reading for IOL power calculation in eyes with previous corneal myopic refractive surgery

PURPOSE

To compare the accuracy of the Equivalent K reading (EKR) from Color Light-Emitting Diode Corneal Topographer (Cassini, iOptics) to that of other no-history formulas for intraocular lens (IOL) power calculation in eyes with previous myopic excimer laser surgery.

SETTING

Centro de Oftalmología Barraquer, Barcelona, Spain.

DESIGN

Retrospective case series.

PATIENTS AND METHODS

In 37 eyes, the refractive outcomes of the Cassini EKR entered into the Haigis formula were compared to those of the Barrett-True K, Haigis-L, Shammas-PL formulas and the Triple-S method combined with the Haigis formula. Optimized lens constants for virgin eyes were used. The mean prediction error (PE), median absolute error (MedAE) and the percentage of eyes with a PE within ±0.25 D, ±0.50 D, ±0.75 D and ±1.00 D were calculated.

RESULTS

The Haigis-L, Shammas-PL and Barrett True-K no-history methods produced a myopic mean PE that was significantly different from zero (p<0.01, p<0.01 and p=0.01, respectively), whereas the mean PEs of Cassini EKR and the Triple-S combined with the Haigis formula were not different from zero. Repeated measures ANOVA disclosed a significant difference among all methods (p<0.0001). The MedAE of the Cassini EKR, Barrett True-K, Haigis-L, Shammas-PL and Triple-S were, respectively, 0.34D, 0.34D, 0.49 D, 0.48 D and 0.31D (p=0.0026).

CONCLUSIONS

The performance of the combination of standard Haigis formula with Cassini EKR was comparable to other no-history formulas in eyes with previous myopic excimer laser surgery.

Intraocular Lens Power Calculation in Eyes with Previous Excimer Laser Surgery for Myopia: A Report by the American Academy of Ophthalmology

PURPOSE

To review the literature to evaluate the outcomes of intraocular lens (IOL) power calculation in eyes with a history of myopic LASIK or photorefractive keratectomy (PRK).

METHODS

Literature searches were conducted in the PubMed database in January 2020. Separate searches relevant to cataract surgery outcomes and corneal refractive surgery returned 1169 and 162 relevant citations, respectively, and the full text of 24 was reviewed. Eleven studies met the inclusion criteria for this assessment; all were assigned a level III rating of evidence by the panel methodologist.

RESULTS

When automated keratometry was used with a theoretical formula designed for eyes without previous laser vision correction, the mean prediction error (MPE) was universally positive (hyperopic), the mean absolute errors (MAEs) and median absolute errors (MedAEs) were relatively high (0.72-1.9 diopters [D] and 0.65-1.73 D, respectively), and a low (8%-40%) proportion of eyes were within 0.5 D of target spherical equivalent (SE). Formulas developed specifically for this population requiring both prerefractive surgery keratometry and manifest refraction (i.e., clinical history, corneal bypass, and Feiz-Mannis) produced a proportion of eyes within 0.5 D of target SE between 26% and 44%. Formulas requiring only preoperative keratometry or no history at all had lower MAEs (0.42-0.94 D) and MedAEs (0.30-0.81 D) and higher (30%-68%) proportions within 0.5 D of target SE. Strategies that averaged several methods yielded the lowest reported MedAEs (0.31-0.35 D) and highest (66%-68%) proportions within 0.5 D of target SE. Even after using the best-known methods, refractive outcomes were less accurate in eyes that had previous excimer laser surgery for myopia compared with those that did not have it.

CONCLUSIONS

Calculation methods requiring both prerefractive surgery keratometry and manifest refraction are no longer considered the gold standard. Refractive outcomes of cataract surgery in eyes that had previous excimer laser surgery are less accurate than in eyes that did not. Patients should be advised of this refractive limitation when considering cataract surgery in the setting of previous corneal refractive surgery. Conclusions are limited by the small sample sizes and retrospective nature of nearly all existing literature in this domain.

Accuracy of intraocular lens formulas using total keratometry in eyes with previous myopic laser refractive surgery

Objectives

This comparative study aimed to determine if total keratometry (TK) from IOLMaster 700 could be applied to conventional formulas to perform IOL power calculation in eyes with previous myopic laser refractive surgery, and to evaluate their accuracy with known post-laser refractive surgery formulas.

Methods

Sixty-four eyes of 49 patients with previous myopic laser refractive surgery were evaluated 1 month after cataract surgery. A comparison of the prediction error was made between no clinical history post-laser refractive surgery formulas (Barrett True-K, Haigis-L, Shammas-PL) and conventional formulas (EVO, Haigis, Hoffer Q, Holladay I, and SRK/T) using TK values obtained with the optical biometer IOLMaster 700 (Carl Zeiss Meditec), as well as Barrett True-K with TK.

Results

The mean prediction error was statistically different from zero for Barrett True-K, Barrett True-K with TK, Haigis-L, Shammas-PL, and Holladay I with TK. The mean absolute error (MAE) was 0.424, 0.671, 0.638, 0.439, 0.408, 0.424, 0.479, 0.647, and 0.524, and median absolute error (MedAE) was 0.388, 0.586, 0.605, 0.298, 0.294, 0.324, 0.333, 0.438, and 0.377 for Barrett True-K, Haigis-L, Shammas-PL, Barrett True-K TK, EVO with TK, Haigis with TK, Hoffer Q with TK, Holladay I with TK, and SRK/T with TK, respectively. EVO TK followed by Barrett True-K TK and Haigis TK achieved the highest percentages of patients with absolute prediction error within 0.50 and 1.00 D (68.75%, 92.19%, and 64.06%, 92.19%, respectively)

Conclusions

Formulas combined with TK achieve similar or better results compared to existing no-history post-myopic laser refractive surgery formulas.

New method for intraocular lens power calculation using a rotating Scheimpflug camera in eyes with corneal refractive surgery

To introduce and evaluate a refraction-based method for calculating the correct power of the intraocular lens (IOL) in eyes with corneal refractive surgery and to compare the results here to previously published methods. Retrospective review of medical records was done. Group 1 was used to derive two formulas. From the relevant IOL calculation and postoperative refractive data, the refraction-derived K values (Krd) were calculated using a linear regression analysis. The values obtained with the two formulas were compared to previously published methods in group 2 to validate the results. The following methods were evaluated: Haigis-L, Barrett True-K (no history), Potvin-Hill, BESSt 2, Scheimpflug total corneal refractive power (TCRP) 4 mm (Haigis), Scheimpflug total refractive power (TRP) 4 mm (Haigis), modified Scheimpflug TCRP 4 mm (Haigis), and modified Scheimpflug TRP 4 mm (Haigis). The modified TCRP 4 mm Krd (Haigis) had good outcomes, with 60% and 90% of eyes within ±0.50 D and ±1.00 D of the refractive target, respectively. A new method using modified Scheimpflug total corneal refractive power in the 4.0 mm zone appeared to be an accurate method for determining IOL power in eyes with corneal refractive surgery.

Accuracy of intraocular lens power calculation formulae after laser refractive surgery in myopic eyes: a meta-analysis

Background

To compare the accuracy of intraocular lens power calculation formulae after laser refractive surgery in myopic eyes.

Methods

We searched the databases on PubMed, EMBASE, Web of Science and the Cochrane library to select relevant studies published between Jan 1st, 2009 and Aug 11th, 2019. Primary outcomes were the percentages of refractive prediction error within ±0.5 D and ±1.0 D.

Results

The final meta-analysis included 16 studies using seven common methods (ASCRS average, Barrett True-K no history, Double-K SRK/T, Haigis-L, OCT formula, Shammas-PL, and Wang-Koch-Maloney). ASCRS average yielded significantly higher percentage of refractive prediction error within ±0.5 D than Haigis-L, Shammas-PL and Wang-Koch-Maloney (P = 0.009, 0.01, 0.008, respectively). Barrett True-K no history also yielded significantly higher percentage of refractive prediction error within ±0.5 D than Shammas-PL and Wang-Koch-Maloney (P = 0.01, P < 0.0001, respectively), and a similar result was found when comparing OCT formula with Haigis-L and Shammas-PL (P = 0.03, P = 0.01, respectively).

Conclusion

The ASCRS average or Barrett True-K no history should be used to calculate the intraocular lens power in eyes after myopic laser refractive surgery. The OCT formula if available, can also be a good alternative choice.

Influence of corneal spherical aberration on prediction error of the Haigis-L formula

The purpose of this study is to investigate the relationships between corneal asphericity and Haigis-L formula prediction errors in routine cataract surgery after refractive surgery for myopic correction. This retrospective study included 102 patients (102 eyes) with a history of previous PRK or LASIK and cataract surgery. Axial length, anterior chamber depth, and central corneal power were measured using the optical biometer. On the anterior corneal surface, Q-value, spherical aberration, and ecentricity at 6.0 and 8.0 mm were measured using a rotating Scheimpflug camera. The postoperative refractive outcome at 6 months, mean error, and mean absolute error were determined. Correlation tests were performed to determine the associations between pre-cataract surgery data and the prediction error. The Q-values for 6.0 and 8.0 mm corneal diameter were 1.57 ± 0.70 (range: 0.03~3.44), and 0.82 ± 0.5 (range: -0.10~-2.66). The spherical aberration for 6.0 and 8.0 mm diameter was 1.16 ± 0.39 µm (range: 0.24~2.08 µm), and 3.69 ± 0.87 µm (range: 0.91~5.91 µm). eccentricity for 6.0 and 8.0 mm diameter was -1.22 ± 0.31 (range: -1.85 to -0.17), and -0.82 ± 0.39 (range: -1.63 to 0.32). The spherical aberration for 8.0 mm cornea diameter showed the highest correlations with the predicion error (r = 0.750; p < 0.001). When the modified Haigis-L formula considering spherical aberration for 8.0 mm produced smaller values in standard deviation of mean error (0.45D versus 0.68D), mean absolute error (0.35D versus 0.55D), and median absolute error (0.31D versus 0.51D) than the Haigis formula. Corneal asphericity influences the predictive accuracy of the Haigis-L formula. The accuracy was enhanced by taking into consideration the corneal spherical aberration for the 8.0 mm zone at pre-cataract surgery state.

Femtosecond laser-assisted cataract surgery with implantation of a diffractive trifocal intraocular lens after laser in situ keratomileusis: a case report

Background

We report for the first time, a case of femtosecond laser-assisted cataract surgery (FLACS) with implantation of a diffractive trifocal intraocular lens (IOL) after laser in situ keratomileusis (LASIK).

Case presentation

A 60-year-old man underwent FLACS uneventfully 15 years after myopic LASIK. An AT Lisa tri 839MP IOL was implanted with the expectation of spectacle independence. The Haigis-L formula was chosen for calculation of the IOL power and it provided reliable results. Three months postoperatively, the uncorrected visual acuities were 0.00 logMAR for distance, 0.10 logMAR for intermediate, and 0.10 logMAR for near.

Conclusions

This case suggested that FLACS presents a feasible surgical technique for post-LASIK eyes and that implantation of trifocal IOL can achieve good visual performance in strictly selected cases after myopic LASIK.