Intraocular Lens Power Calculation After Laser In Situ Keratomileusis for Myopia and Hyperopia

Feiz, Vahid; Mannis, Mark J.; Garcia-Ferrer, Francisco; Kandavel, Ganesha; Darlington, Jason K.; Kim, Esther; Caspar, Jeffrey J.; Wang, Jane Ling; Wang, Wei

doi:10.1097/00003226-200111000-00003

Cited by 173 publications

(118 citation statements)

References 6 publications

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“…In a subgroup of patients with available pre-refractive surgery data, the historical, 11 FeizMannis, 12 and corneal power bypassing 13 methods were used to determine refractive corneal power. These derived corneal powers were then used in the SRK-T formula to determine IOL power.…”

Section: Discussionmentioning

confidence: 99%

“…Additionally, such diversity can easily generate confusion rather than accuracy. In the present study, we present the outcomes of a simple method of IOL power calculation after refractive surgery and evaluate its accuracy in comparison with other commonly used methods, namely the clinical history, 11 Feiz-Mannis, 12 and corneal power bypassing 13 methods.…”

Section: Introductionmentioning

confidence: 99%

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Intraocular lens power calculation after corneal refractive surgery

Feiz

Mannis

2004

Current Opinion in Ophthalmology

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Purpose: To report refractive outcomes following phacoemulsification (PE) and posterior chamber intraocular lens (PCIOL) implantation in eyes with previous corneal refractive surgery. Methods: In this retrospective comparative study, 18 consecutive eyes of 14 patients with previous keratorefractive surgery for myopia including photorefractive keratectomy (PRK, 6 eyes; 33.3%) and laser in situ keratomileusis (LASIK, 12 eyes; 66.7%) underwent PE+PCIOL. Computerized corneal topography was employed to determine the flattest keratometric reading within the 3-mm central zone. This value was inserted into the Sanders-Retzlaff-Kraff/T (SRK/T) formula to calculate IOL power. IOL power selected for implantation was 1 D greater than the calculated value described above. Results: Mean age and follow-up period were 54.1±11.5 years and 29.9±26.3 months, respectively. Mean implanted lens power was 18.56±3.86 D which was not significantly different from mean back-calculated IOL power for target refraction (19.04±4.16 D) (P=0.28). There was no significant difference between mean target refraction (-0.94±0.52 D) and achieved postoperative spherical equivalent refractive error (-0.62±1.06) at final follow-up (P=0.28). The achieved spherical equivalent refractive error was within ±0.50 D of intended refraction in 8 (44.4%) eyes, within ±1.0 D in 11 (61.1%) eyes, and within ±2.0 D in 16 (88.9%) eyes. In a subgroup of patients (5 eyes) with complete pre-refractive surgery data, the difference between post-refractive surgery keratometry method and all other methods (P=0.02) and between the current method and the Feiz-Mannis method (P=0.01) was statistically significant. Conclusion:The method suggested herein is simple and independent of pre-refractive surgery data with results comparable to other commonly used methods.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Intraocular lens power calculation after corneal refractive surgery

Feiz

Mannis

2004

Current Opinion in Ophthalmology

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“…Kpost-corr = EffRp (ΔD x 0,19) e) Método de Hammed (17,18) Tomamos igualmente el valor EffRp y realizamos la correción:…”

Section: D) Método De Koch-wang (16)unclassified

El cálculo de la lente intraocular tras cirugía foto-refractiva corneal: Revisión de la literatura

Mesa-Gutiérrez

Ruiz-Lapuente

2009

Arch Soc Esp Oftalmol

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RESUMENObjetivo: Revisión de las distintas fórmulas de corrección del poder refractivo de la córnea (Kpost) y de la estimación de la posición efectiva de la lente (ELP) para la cirugía de cataratas después de cirugía refractiva corneal. Método: Revisión de la literatura médica. Resultados: Es necesario realizar una corrección de la Kpost para el cálculo de la lente intraocular tras cirugía refractiva. Existen diferentes vías dependiendo de la información disponible. Para estimar la ELP es necesario realizar una nueva corrección. Es aconsejable disponer de la queratometría previa (Kpre) y posterior (Kpost) a la cirugía y la refracción previa (Rpre) y posterior (Rpost). De esta manera, podremos realizar la corrección doble-K de Aramberri en la fórmula de cálculo. Conclusiones: Es conveniente registrar la refracción y queratometría (K, y método) previamente a la cirugía refractiva: la Kpre es crítica para el cálcu-lo de la ELP.Palabras clave: Lente intraocular, cirugía refractiva, potencia dióptrica corneal, cirugía cataratas, corrección doble-K, posición efectiva de la lente. ABSTRACTObjective: Revision of methods for estimating corneal power (Kpost) and effective lens position (ELP) for cataract surgery after corneal refractive surgery. Methods: Review of medical literature. Results: To calculate the intraocular lens that achieves emetropia after corneal refractive surgery it is necessary to correct the Kpost and to estimate the effective lens position again correcting it. There are different formulae depending on the available information. Ideally, we need pre (Kpre) and posttreatment keratometry record (Kpost) and pre (Rpre) and post (Rpost) refraction. In this way, we can use the Aramberri's double-K method in the formula for calculating intraocular lens power. Conclusions: Previously to keratorefractive procedure is advisable to have pre-treatment refraction and keratometry (K and method) registered: Kpre value is critical to calculate the ELP (Arch Soc Esp Oftalmol 2009; 84: 283-292).

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“…Six of 10 eyes (60%) showed a hyperopic outcome, which should be taken into account when choosing an IOL power. Three eyes with corneal radii over 10 mm showed calculation errors exceeding 71.0 D (Table 1, Feiz-Mannis, 14 double-K, 15 or adjusted effective refractive power (EffRP adj ) method. 5,16 On the other hand, IOL power calculation is possible without the original data using contact lens over-refraction method, 6,7 correlating axial length and corneal radius correcting factors, 17 corneal topography (Orbscan II), 18 or ray tracing.…”

Section: Contribution Of C-scan Central Corneal Power Measurements Tomentioning

confidence: 99%

Intraocular lens power calculation using ray tracing following excimer laser surgery

Rabsilber

Reuland

Holzer

et al. 2006

Eye

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Purpose To evaluate intraocular lens (IOL) power calculation using ray tracing in patients presenting with cataract after excimer laser surgery. Methods Ten eyes of seven consecutive patients who presented for cataract surgery following excimer laser treatment without any pre-refractive biometry data were enrolled in this prospective clinical study. Preoperatively, IOL power calculation was performed using a ray tracing software called OKULIX. Keratometry data (C-Scan) were imported and axial length (IOLMaster) was entered manually. Accuracy of IOL power calculation was investigated by subtracting attempted and achieved spherical equivalent. Conclusions IOL power calculation after excimer laser surgery can be difficult, especially when pre-refractive keratometry values are not available. In these cases, ray tracing combined with corneal topography measurements provides reliable and satisfactory postoperative results. However, it is advisable to be careful when calculating IOL power for eyes with corneal radii exceeding 10 mm because of slightly higher prediction errors.

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Intraocular Lens Power Calculation After Laser In Situ Keratomileusis for Myopia and Hyperopia

Abstract: The pre-LASIK refraction can be used theoretically to determine an accurate IOL power.

Cited by 173 publications

References 6 publications

Intraocular lens power calculation after corneal refractive surgery

Intraocular lens power calculation after corneal refractive surgery

El cálculo de la lente intraocular tras cirugía foto-refractiva corneal: Revisión de la literatura

Intraocular lens power calculation using ray tracing following excimer laser surgery

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