Intraocular lens power calculation for lens exchange

PURPOSE: To examine patients who had intraocular lens (IOL) exchange for large postoperative refractive errors and determine the factors that contributed to the error in IOL power calculation. SETTING: Thirteen affiliated hospitals in Japan. METHODS: This study comprised 34 cases that required IOL exchange because of large refractive errors after primary lens implantation. Patients with intraoperative complications were excluded from the study. The potential contribution of axial length, corneal refractive power, IOL manufacturer, and IOL fixation to errors in the predicted power was examined retrospectively. Axial length was calculated by the SRK/T and Holladay formulas using refraction after primary IOL implantation. RESULTS: There was no statistical difference between the corneal refractive power before and after cataract surgery. The axial lengths calculated using the SRK/T and Holladay formulas were longer than the ultrasonic axial lengths in 24 and 23 cases, respectively. Using IOLs from the same manufacturer for both primary implantation and exchange reduced the error in predicted refraction. CONCLUSION: Axial length and IOL manufacturer were important factors in predicting refraction power in eyes requiring IOL exchange.     

Intraocular lens calculations status after corneal refractive surgery

With the increasing number of keratorefractive surgical procedures, an increasing number of cataract surgeries in eyes after keratorefractive surgery is anticipated within a few decades. Although cataract extraction seems to be feasible without major technical obstacles, intraocular lens (IOL) power calculation turned out to be problematic. Insertion of the measured average K-readings (= "central corneal power" = keratometric diopters) after myopic radial keratotomy (RK), photorefractive keratectomy (PRK), or laser in situ keratomileusis (LASIK) into standard IOL power-predictive formulas commonly results in substantial undercorrection and postoperative hyperopic refraction or anisometropia. In this article, the major reasons for IOL power miscalculations (which are different for RK versus RRK/LASIK) are discussed based on model calculations and based on case series of cataract surgeries, methods for improved assessment of keratometric diopters as the major underlying problem are exemplary illustrated, and finally a clinical step-by-step approach to minimize IOL power miscalculations status after corneal refractive surgery is suggested. The "clinical history method" (i.e., subtraction of the spherical equivalent [SEQ] change after refractive surgery from the original K-reading) should be applied whenever refraction and K-reading before the keratorefractive procedure are available to cataract surgeons. In addition, more than one modern third-generation formula (e.g., Haigis, Hoffer Q, Holladay 2, or SRK/T) but not a regression formula (e.g., SRK I or SRK II) should be applied and the highest resulting IOL power should be used for the implant.     

Intraocular lens power calculation after refractive surgery

PURPOSE: To analyze the results of phacoemulsification cataract surgery in eyes that had had refractive surgery and to compare the predictability of various methods of intraocular lens (IOL) power calculation. SETTING: Instituto de la Visión, Buenos Aires, Argentina. METHODS: The study involved 7 cases that had phacoemulsification after radial keratotomy or laser in situ keratomileusis. The spherical equivalent (SE) and visual acuity were evaluated preoperatively and postoperatively to assess the changes before cataract development. The IOL power calculated with conventional keratometry (CK), adjusted keratometry, the clinical history method (CHM), corneal topography (CT), and the contact lens method (CLM) was compared with the final refractive and keratometric results measured with the BackCalcs (Holladay(R) IOL Consultant Program, Holladay Consulting, Inc.) to assess the accuracy and predictability of each method. RESULTS: The mean SE was -4.82 diopters (D) +/- 5.13 (SD) before phacoemulsification and +0.19 +/- 1.01 D after phacoemulsification, and the mean best corrected visual acuity was 0.39 +/- 0.07 (20/50) and 0.80 +/- 0.06 (20/25), respectively. CONCLUSIONS: Post-phacoemulsification refraction in cases with previous refractive surgery appeared to be predictable when the appropriate calculation method was applied. When all the data were available, the CHM provided the best results. Adjusted keratometry and CT seemed to be more accurate than CK and the CLM.     

Corneal topography and postoperative refraction after cataract phacoemulsification following radial keratotomy

We present one case in which phacoemulsification was performed seven years after radial keratotomy (RK). A 55-year-old military police officer had undergone successful bilateral RK for the correction of myopia seven years before he developed a cataract in his left eye. Pre-RK keratometric and refractive data and post-RK myopia reduction were not available. We relied upon corneal topography to measure corneal refractive power. We took the Effective Refractive Power (EffRP) index from EyeSys Holladay's Diagnostic Summary and used SRK-T formula for IOL calculation. A-scan axial length readings were consistent and reliable (AL = 26.0 mm). Aiming at postoperative emmetropia, we implanted a +20D PC IOL (A cost. = 118) was implanted. The lens was expected (SRK-T formula) to give a -1.35D postoperative refraction. After uneventful cataract surgery, corneal topography showed significant corneal instability with central corneal flattening in the first postoperative weeks, mild central corneal steepening at week 6, and return to preoperative corneal curvature at week 23. One year after cataract extraction, the patient's spherical equivalent is +1.12D, showing a prediction error of about 2.5 diopters.     

角膜屈光手术后人工晶状体植入度数的计算

目的分析应用 HolladayⅡ公式计算角膜屈光手术后人工晶状体(IOL)植入度数的准确性。方法角膜屈光手术后患者15例(15只眼),分成两组行超声乳化白内障吸除术联合 IOL 植入术。第一组(8只眼)应用 HolladayⅡ公式进行 IOL 度数计算,角膜屈光度根据手术医师经验计算获得,为 KS。第二组(7只眼)应用同一公式,但角膜屈光度应用患者的屈光度数计算获得,为 KR。比较超声乳化白内障吸除术后1个月的屈光度数与术前的预期屈光度数,并应用两者差的绝对值作为标准进行分析。结果两组超声乳化白内障吸除术后1个月的角膜屈光度数与术前预期屈光度数差的绝对值平均值依次为(0.90±0.22)D 和(0.99±0.22)D。结论应用 HolladayⅡ公式计算角膜屈光手术后行超声乳化白内障吸除术时植入 IOL 度数的准确性相对较高。KS 与 KR 在 HolladayⅡ公式中应用的差异无统计学意义。(中华眼科杂志,2006,42:888-891)     

Reliability of a new correcting factor in calculating intraocular lens power after refractive corneal surgery

PURPOSE: To test the reliability of a corneal radius correcting factor (R factor) in calculating intraocular lens (IOL) power in eyes that developed cataract after refractive surgery and compare it with the clinical history (CHM) and double-K (DKM) methods. SETTING: Department of Ophthalmology, Second University of Naples, Naples, Italy. METHODS: Nineteen eyes from the literature that underwent cataract extraction and IOL implantation after refractive surgery were used to compare actual postoperative and expected refractive errors utilizing the R factor, CHM, and DKM. Intraocular lens powers were calculated with 3 formulas: SRK/T, Hoffer Q and Holladay 1. The differences were evaluated with the Wilcoxon test and Spearman correlation. RESULTS: With the R factor SRK/T and Holladay 1 formulas gave the best results; 16 (84.2%) and 17 (89.5%) eyes were within +/-2 diopters (D) of emmetropia. With CHM, the best results were obtained using the SRK/T and Holladay 1 formulas; with both formulas 12 (63.2%) eyes were within +/-2 D of emmetropia. With DKM, the best results were obtained using SRK/T and Holladay 1 formulas; with both formulas 10 eyes (52.63%) were in the range of +/-2 D from emmetropia. CONCLUSIONS: The R factor can be used with the SRK/T or Holladay 1 formula because this method seems comparable or superior to DKM and CHM.     

角膜屈光术后人工晶状体度数计算的临床观察

目的：探讨角膜近视屈光术后白内障患者的人工晶状体度数的计算方法,观察初步的临床效果。方法：回顾性分析2013－03／2015－06于我院行白内障手术同时伴有角膜近视屈光手术史的患者14例23眼。根据患者既往角膜手术方式分为 LASIK （ laser in situ keratomileusis）组9例15眼,RK（ radial keratotomy）组5例8眼。将每例患者的角膜地形图中央2．5 mm最低点曲率值,带入SRK－T公式,按照预留－1．00～－1．50 D选择人工晶状体度数,完成常规的白内障超声乳化联合人工晶状体植入术。术后随访3mo,观察术后视力、矫正视力和屈光状态。计算出术后人工晶状体计算公式的预测屈光误差,分别与www．iolcalc．org网站上的Shammas公式和Barrett True K公式进行比较,观察其应用效果,采用独立样本t检验进行统计分析。结果：LASIK组和RK组相比,两组患者术后3 mo的裸眼视力（LogMAR）分别是0．15±0．11、0．21±0．16,术后屈光度分别是－0．43±1．04、－1．52±1．01D,SRK－T公式预测屈光误差分别是－0．71±0．80、0．43±0．99,LASIK组均优于RK组且两组间差异均有统计学意义（ P＜0．05）。将本研究方法分别与Shammas公式和Barrett True K公式相比,观察各种公式的预测屈光误差,本研究方法的屈光误差最小,但是差异无统计学意义（P＞0．05）。结论：应用研究方法的术后屈光状态均为轻度近视,适用于因近视行角膜屈光手术的白内障患者进行人工晶状体度数的选择,此方法对于LASIK手术史患者的人工晶状体度数预测性更佳。     

LASIK/PRK术后人工晶状体度数计算的研究进展

随着屈光不正患者数量的增加及角膜屈光手术的盛行,越来越多早期选择角膜屈光手术(LASIK/PRK)矫正高度近视的患者如今面临着白内障手术,然而,用常规方法计算这部分患者的人工晶状体度数往往是不精确的。目前的第三代和第四代公式过高地估计了角膜屈光力,导致人工晶状体度数矫正不足,从而出现术后的远视漂移。而传统的角膜地形图采用2.5～3.2mm范围环上的角膜计算角膜屈光力,忽略了角膜中央的真实曲率,导致角膜屈光术后尤其是偏中心切削患者术后出现严重的屈光误差。本文旨在总结LASIK/PRK术后患者人工晶状体度数计算最新的误差来源以及最新计算方法,为提高屈光术后患者人工晶状体度数计算的准确性提供更多的选择。     

Cataract surgery in patients with prior refractive surgery

As the number and types of keratorefractive procedures increase and as the baby boomer population moves into the "cataractous decades," the number of patients requiring cataract surgery following refractive surgery grows larger each year. While technological advances in surgical instrumentation and intraocular lens (IOL) design allow us to perform cleaner, faster, and more reliable cataract extractions, the ultimate postoperative refraction depends primarily on calculations performed before surgery. Third-generation IOL formulas ( Haigis, Hoffer Q, Holladay 2, or SRK/T) provide outstanding accuracy when used for eyes with physiologic, prolate corneas. In addition, most instruments used today for measuring corneal curvature and power were designed before the era of refractive surgery. These formulas and instruments make assumptions about the anatomy and refractive properties of the cornea that are no longer valid following most keratorefractive procedures. These breakdowns in IOL calculation often result in a "refractive surprise" after cataract surgery, which may require subsequent surgical correction. This article examines recent publications of modeling studies of various methods for estimating effective K values for IOL calculation, cataract surgery case series following refractive surgery, new corneal topography technologies and methods for correcting "refractive surprises" postoperatively.     

Measuring corneal power for intraocular lens power calculation after refractive surgery. Comparison of methods

PURPOSE: To find a more accurate and predictable method for intraocular lens (IOL) power calculation in eyes after refractive surgery. SETTING: Department of Ophthalmology, Kangnam St. Mary's Hospital, Seoul, Korea. METHODS: The accuracy of the following methods for calculating IOL power in 132 eyes after PRK or LASIK was compared: manual keratometry, hard contact lens, refraction-derived keratometry at the corneal plane, and the refraction-derived keratometry at the spectacle plane. Based on this comparison, the IOL power was calculated in the 2 eyes of a patient using refraction-derived keratometry at the spectacle plane with the SRK II formula. Cataract surgery with IOL implantation was then performed. RESULTS: The largest corneal power values were obtained using a manual keratometer and the smallest using refraction-derived keratometry at the spectacle plane (P <.001). In the patient having cataract surgery with IOL implantation, near target refraction was achieved with minimal error in IOL power. CONCLUSIONS: If the corneal power is known before refractive surgery, the use of the smallest value of those obtained using refraction-derived keratometry and the hard contact lens method is recommended. However, if the corneal power before refractive surgery is unknown, the use of the hard contact lens method is recommended.     

Refractive error in cataract surgery after previous refractive surgery

Bilateral cataract extraction with posterior chamber intraocular lens (IOL) implantation was performed in a patient after previous photorefractive keratectomy, radial keratotomy (RK) combined with astigmatic keratotomy, and retreatment of RK. Significant hyperopic error was observed after cataract surgery, and the IOLs were eventually exchanged in both eyes. A review of this case found that the refractive error was smaller when a refraction-derived keratometric value was selected for IOL power calculation. Nevertheless, hyperopic error still occurred.     

Intraocular lens power calculation after radial keratotomy: estimating the refractive corneal power

PURPOSE: To evaluate the most accurate method for corneal power determination in patients with previous radial keratotomy (RK). SETTING: University of Texas Southwestern Medical Center at Dallas, Dallas, Texas, USA. METHODS: A retrospective review of data for 16 eyes of 14 patients with a history of RK and subsequent phacoemulsification and posterior chamber intraocular lens (IOL) implantation was performed. Outcome measures included axial length, postoperative topography, type and power of IOL implanted, and postoperative spherical equivalent (SE) refraction at 3 to 6 months. Average central corneal power (ACCP) was defined as the average of the mean powers of the central Placido rings. For each eye, simulated K-readings and different values of ACCP computed corresponding to different central corneal diameters were used in each case, along with the implanted IOL power, to back-calculate the SE refraction (Ref) via the double-K adjusted Holladay 1 IOL formula. The predicted refractive error was hence computed as (Ref - SE), both in algebraic and absolute values. RESULTS: The ACCP over the central 3.0 mm (ACCP(3mm)) yielded the lowest absolute predicted refractive error (0.25 +/- 0.38 diopters [D]), which was statistically lower than the error for ACCP(1mm) (P<.001) and for the simulated K-value (P = .033). It also resulted in 87.5% of eyes being within +/-0.50 D and 100% within +/-1.00 D of the actual postoperative refraction. CONCLUSIONS: Corneal refractive power after RK was best described by averaging the topographic data of the central 3.0 mm area. Applying this method, together with a double-K IOL formula, achieved excellent IOL power predictability.     

Pitfalls of IOL power prediction after photorefractive keratectomy for high myopia -- case report,practical recommendations and literature review

BACKGROUND AND PURPOSE: Published experience with eyes after keratorefractive correction of myopia indicates that insertion of the average keratometric readings into standard IOL power predictive formulas will frequently result in substantial undercorrection and postoperative hyperopic refraction or anisometropia after cataract surgery depending on the amount of myopia corrected previously. The purpose of this paper is to discuss the accentuated differences of various approaches to minimize IOL power miscalculations by describing a case report of a patient with excessive myopia as well as a review of the literature. PATIENT AND METHODS: A 50-year old lady presented for cataract surgery on her left eye after having PRK seven years ago elsewhere (refraction - 25.5 - 3.0/20 degrees, central keratometric power 43.0 diopters [D]). Central power before cataract extraction was measured to be 35.5 D (Zeiss Keratometer) and 36.5 D (TMS-1 topography analysis) and refraction was - 3.0 D (before onset of index myopia). Orbscan slit scanning topography analysis displayed an anterior surface power of 36.8 D and a posterior surface power of - 9.3 D. Total axial length was 31.93 mm (optical biometry using Zeiss IOL-Master). The contralateral eye after PRK suffering from a comparable excessive myopia had required an exchange of the IOL implant because of intolerable anisohyperopia of + 6.0 D after primary cataract extraction elsewhere. RESULTS: Corrected corneal power values for the left eye were calculated as follows: (1) spherical equivalent (SEQ) change at spectacle plane 19.0 D, (2) SEQ change at corneal plane 26.2 D, (3) separate consideration of anterior and posterior curvature 27.5 D, (4) consideration of the IOL power misprediction on the fellow eye 29.5 D, (5) subtraction of 24 % of the SEQ change at the spectacle plane from the actually measured keratometry value 29.7 D, (6) clinical estimate from regression analysis performed earlier 30.5 D, (7) change of anterior surface power 34.5 D. Deciding for a presumably "real" corneal power of 28.0 D the Haigis formula was used to aim for - 2.0 D since the patient preferred to read uncorrected. Thus, a 21.0 D IOL was implanted uneventfully in the capsular bag. The stable refraction postoperatively was - 3.5 - 1.0/20 degrees and visual acuity increased to 20/30. Therefore, the "real" power of that cornea must have been around 30 D. CONCLUSIONS: After corneal refractive surgery, various techniques to determine the current corneal power should be compared and the value around which results tend to cluster should be relied on to avoid hyperopia after cataract surgery with lens implantation. In those cases where keratometry and refraction before PRK/LASIK are available, the gold standard is still to subtract the change of the SEQ at the corneal plane from the preoperative central keratometric power, although in the present case report the subtraction of 24 % of the SEQ change at the spectacle plane from the measured corneal power value seemed to produce the best result. Pure subtraction of the SEQ change at the spectacle plane from the corneal power value before refractive surgery has to be avoided in eyes with excessive myopia. The most reliable corrected power value should be inserted in more than one modern third-generation formula (such as Haigis, Hoffer Q, Holladay 2, SRK/T) and the highest power IOL should be implanted. In all instances, the cataract surgeon has to make sure that the corrected K-reading is not wrongly re-converted within the IOL power calculation formula used.     

Cataract surgery after holmium:YAG laser thermal keratoplasty

A 64-year old man had noncontact holmium:YAG (Ho:YAG) laser thermal keratoplasty (LTK) performed in the left eye on March 10, 1998, and in the right eye on January 11, 1999. The patient achieved 1.3 diopters (D) and 1.4 D of corneal steepening in the right and left eye, respectively, which was the desired amount as his refractive error before Ho:YAG LTK was low. At the 3-month postoperative examination of the left eye, cortical cataracts were observed in both eyes. Approximately 1 year later, bilateral cataract extraction was recommended because of patient-reported decreased vision at distance and near and difficulty with vision in the presence of glare. Cataract surgery and intraocular lens (IOL) implantation was performed in both eyes in August 1999 using the keratotomy readings taken after noncontact Ho:YAG LTK to calculate IOL power. Although slight flattening of the cornea occurred after cataract extraction, the refractive outcomes achieved by noncontact Ho:YAG LTK were generally preserved.     

中老年近视患者的角膜屈光手术和晶状体屈光手术的选择

目的：探讨中老年近视患者的角膜屈光手术和晶状体屈光手术的选择。方法：两例５０岁以上双眼近视患者的右眼均行白内障除人工晶状体植入术,两者的左眼先行角膜屈光手术,３年后又行白内障摘除人工晶状体植入术。术后随访最短４个月最长４年,对术后情况进行对比、回顾分析。结果;未经角膜屈光手术的白内障摘除人工晶状体植入术的效果最好。结论：近视患者的屈光矫正手术的术式选择,应根据年龄、晶状体情况,近视程度和单、双眼情     

Clear lens extraction to correct hyperopia in presbyopic eyes with or without arcuate keratotomy for pre-existing astigmatism

This retrospective study evaluates visual (functional) and refractive outcome of correcting hyperopia (i.e. 2.5 D or more) by means of a cataract procedure and simultaneously the pre-existing clinical significant astigmatism (1.5 D or more with the rule; 1 D or more against the rule), if present, by means of an arcuate keratotomy. Nine eyes undergoing clear lens extractions with intraocular lensimplantation (IOL) in combination with arcuate keratotomy (group one) and 29 eyes without arcuate kertotomy (group two) are included in the study. The mean age at the time of surgery was 62.89 years (range, 50 to 83) in group one and 68.17 years (range, 53 to 86) in group two. For calculation of the lens power a modified SRK II program, aiming at emmetropia was used. In only one highly hyperopic patient the Holladay I formula was used to calculate two piggyback lenses. A modified Istre nomogram was used to determine the surgical parameters of the arcuate keratotomy. The Cravy formula and the Holladay, Cravy, Koch vector analysis were used to determine the change in refractive cylinder results. Patients were followed postoperatively for a mean of 2.8 months in group one and 7.5 months in group two. In group one, 6 out of 9 eyes achieved a postoperative refraction within +/- 0.5 D of intended refraction and 8 out of 9 were within +/- 1 D of intended refraction. In group two, it was 15/29 and 24/29 respectively. Postoperatively, the uncorrected visual acuity was 20/40 or better in all eyes of group one (9/9) and in 27/29 eyes of group two. None of the eyes in both groups lost two or more lines of the best corrected visual acuity. Clear lens extraction with IOL is an effective and safe procedure for the correction of hyperopia in a presbyopic age group. In combination with an arcuate keratotomy, pre-existing astigmatism can be corrected simultaneously.     

Predictability of intraocular lens power calculations based on formulas on the ASCRS website after myopic laser refractive surgery

PurposeThis work was conducted in order to study the intraocular lens (IOL) power predictability of formulas provided by the American Society of Cataract and Refractive Surgery (ASCRS) website for patients who had undergone myopic laser refractive surgery.MethodsIn this retrospective study, we analyzed 11 eyes (from nine patients) that had previously undergone myopic laser-assisted in situ keratomileusis or photorefractive keratectomy and experienced subsequent phacoemulsification and posterior-chamber IOL implantation. Using the adjusted central K (keratometry), axial length, and the SRK/T formula, we compared the original desired refraction to the manifest refraction 1 month after cataract surgery. According to the postoperative manifest refraction, we compared the IOL power calculated using the different methods on the ASCRS website.ResultsBefore cataract surgery, the mean adjusted central K reading was 35.90 diopters (D) (range 29.24–41.58 D), and the mean axial length was 28.53 mm (range 25.77–32.79 mm). Postoperatively, the mean arithmetic refractive prediction error was 0.50 D (range ?1.72 D to 2.33 D), and the mean absolute error was 1.07 D (range 0.01–2.33 D). The most reliable method was the Masket method in combination with the double K Holladay I formula. The predictability of the adjusted central K method and the Masket method in combination with the single-K SRK/T formula was as precise as that of the modified Masket method in combination with the double K Holladay I formula and the Shammas method in combination with the Shammas-PL formula.ConclusionASCRS offers the use of a postrefractive IOL calculator online, free of charge. The Masket method in combination with the double K Holladay I formula is the best choice for IOL power prediction after laser-assisted in situ keratomileusis or photorefractive keratectomy surgery. The adjusted central K method is a convenient and effective strategy with which to correct central corneal power. However, double K formulas designed for adjusted central K should be used for more accurate predictions of lens position.     

A comparative analysis of intraocular lens power calculation methods after myopic excimer laser surgery

PURPOSE: To compare the accuracy and predictability of different intraocular lens (IOL) power calculation methods in eyes after myopic excimer laser surgery. METHODS: Phacoemulsification and IOL implantation outcomes in 37 eyes of 37 patients with prior LASIK or photorefractive keratectomy were documented (amount of correction=-6.92+/-3.12 diopters (D), range: -2.00 to -13.00 D). The theoretical IOL power that would have resulted in emmetropia was calculated (IOLemme). Using the clinical history keratometry and biometry, the IOL power was calculated using the following methods: Sanders, Retzlaff, Kraff (SRK)-T, SRK-T Double-K (DK), Holladay 1 DK, Hoffer Q DK, Holladay 2 DK, Feiz-Mannis, and Ladas-Stark corneal bypass. The calculated IOL power was compared to IOLemme and used to determine the mean error and mean absolute error of refractive outcome for each eye. RESULTS: The calculated IOL power using the SRK-T, Feiz-Mannis, and Holladay 1 DK methods were significantly different from IOLemme. The lowest mean absolute error was achieved using the Hoffer Q DK method (0.75+/-0.52 D), Holladay 2 DK (0.75+/-0.62 D), SRK-T DK (0.76+/-0.60 D), and Ladas-Stark (0.83+/-63 D). With the SRK-T DK method, 51.4% of eyes were within +/-0.50 D of emmetropia and 67.6% of eyes were within +/-1.00 D. The Holladay 2 DK method had the highest percentage (81.1%) of eyes within +/-1.00 D and 45.9% within +/-0.50 D. CONCLUSIONS: The refractive results of IOL implantation using the same biometry data in eyes after LASIK can vary markedly. The SRK-T DK, Hoffer Q DK, and Holladay 2 DK methods resulted in the highest accuracy.     

Accuracy and predictability of intraocular lens power calculation after laser in situ keratomileusis

PURPOSE: To study the accuracy and predictability of intraocular lens (IOL) power calculation in eyes that had laser in situ keratomileusis (LASIK). SETTING: Gimbel Eye Centre, Calgary, Alberta, Canada. METHODS: Refractive outcomes in 6 cataract surgery and lensectomy eyes after previous LASIK were analyzed retrospectively. Target refractions based on measured and refraction-derived keratometric values were compared with postoperative achieved refractions. Differences between target refractions calculated using 5 IOL formulas and 2 A-constants and achieved refractions were also compared. RESULTS: The refractive error of IOL power calculation in postoperative LASIK eyes was significantly reduced when refraction-derived keratometric values were used for IOL power calculation. Persistent residual hyperopia still occurred in some cases; this was corrected by hyperopic LASIK. Refractive results appeared more accurate and predictable when the Holladay 2 or Binkhorst 2 formula was used for IOL power calculation. CONCLUSION: Hyperopic error after cataract surgery in post-LASIK eyes was significantly reduced by using refraction-derived keratometric values for IOL power calculation. Persistent hyperopic error was corrected by hyperopic LASIK.