Total keratometry for determination of true corneal power after myopic small-incision lenticule extraction

Lischke, Roman; Mayer, Wolfgang J.; Feucht, Nikolaus; Wiltfang, Rainer; Kook, Daniel; Priglinger, Siegfried; Luft, Nikolaus

doi:10.1097/j.jcrs.0000000000000630

Cited by 3 publications

(2 citation statements)

References 13 publications

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“…Several methods have been introduced to address these sources of error and to reduce refractive surprises after keratorefractive surgery [ 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 ]. New technologies for corneal power measurements that incorporate measurements of the anterior and posterior corneal radii (e.g., total keratometry [ 10 ]) were established to enable more accurate predictions. Moreover, sophisticated IOL power calculation formulae have been developed by means of empirical optimization; some of which consider pre-keratorefractive surgery data (Masket [ 11 ], Modfied-Masket or Barrett True-K formula), and some do not incorporate any preoperative values (Shammas [ 12 ], Barrett True-K no history, Potvin-Hill [ 13 ] or Haigis-L formula [ 14 ]).…”

Section: Introductionmentioning

confidence: 99%

IOL Power Calculations and Cataract Surgery in Eyes with Previous Small Incision Lenticule Extraction

Lischke

Sekundo²,

Wiltfang³

et al. 2022

JCM

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Small incision lenticule extraction (SMILE), with over 5 million procedures globally performed, will challenge ophthalmologists in the foreseeable future with accurate intraocular lens power calculations in an ageing population. After more than one decade since the introduction of SMILE, only one case report of cataract surgery with IOL implantation after SMILE is present in the peer-reviewed literature. Hence, the scope of the present multicenter study was to compare the IOL power calculation accuracy in post-SMILE eyes between ray tracing and a range of empirically optimized formulae available in the ASCRS post-keratorefractive surgery IOL power online calculator. In our study of 11 post-SMILE eyes undergoing cataract surgery, ray tracing showed the smallest mean absolute error (0.40 D) and yielded the largest percentage of eyes within ±0.50/±1.00 D (82/91%). The next best conventional formula was the Potvin–Hill formula with a mean absolute error of 0.66 D and an ±0.50/±1.00 D accuracy of 45 and 73%, respectively. Analyzing this first cohort of post-SMILE eyes undergoing cataract surgery and IOL implantation, ray tracing showed superior predictability in IOL power calculation over empirically optimized IOL power calculation formulae that were originally intended for use after Excimer-based keratorefractive procedures.

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Section: Introductionmentioning

confidence: 99%

IOL Power Calculations and Cataract Surgery in Eyes with Previous Small Incision Lenticule Extraction

Lischke

Sekundo²,

Wiltfang³

et al. 2022

JCM

Self Cite

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show abstract

“…As of today, however, only theoretical data on the validity of TK-based IOL power calculation formulae for post-SMILE eyes are available. 19 Hence, the aim of this study was to evaluate the accuracy of different IOL power calculation formulae utilizing TK as well as the ray tracing method in post-SMILE eyes that underwent actual cataract surgery.…”

Section: Introductionmentioning

confidence: 99%

Intraocular lens power calculation using total keratometry and ray tracing in eyes with previous small incision lenticule extraction – A case series

Lischke,

Wiltfang,

Bechmann

et al. 2024

American Journal of Ophthalmology Case Reports

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Comparison of Corneal Power Difference Maps with Achieved Myopic Correction Using Scheimpflug Tomography After LASIK, PRK, and SMILE

Moshirfar,

Harvey,

Wang

et al. 2023

OPTH

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Purpose To compare corneal power difference maps (∆maps) obtained from the Pentacam in patients with 1 year follow-up after LASIK, PRK, and SMILE with further stratification to low, moderate, and high myopia. Patients and methods This retrospective study was comprised of patients who had preoperative and 1-year postoperative power maps that were obtained–front sagittal (SagF), refractive power (RP), true net power (TNP), and total corneal refractive power (TCRP)–for evaluation. Measurements were recorded and compared at the 4mm, 5mm and 6mm pupil and apex zones. Comparisons were made between each specific power ∆map and the surgically induced refractive change (SIRC). Further analysis of the ∆maps was performed based on degree of myopia (high, moderate, and low). Correlation and agreement were also assessed with regression and limits of agreement (LoA). Results There were 172 eyes in the LASIK group, 187 eyes in the PRK group, and 46 eyes in the SMILE group. In the LASIK group, TNP ∆map at 5mm pupil zone had the least absolute mean difference with SIRC (0.007 ± 0.42D). In the PRK group, TNP ∆map at 5mm apex zone was most accurate compared to SIRC (0.066 ± 0.45D). In the SMILE group, TCRP ∆map at 4mm apex zone had the closest absolute value when compared to SIRC (0.011 ± 0.50D). There was good correlation and agreement for all three surgery groups, LASIK: r = 0.975, LoA −0.83D to +0.83D, PRK: r = 0.96, LoA −0.83D and +0.95D, and SMILE: r = 0.922, LoA −0.97 D to +0.99D. Conclusion TNP ∆maps most accurately measured corneal power in the LASIK and PRK groups while TCRP ∆maps were most accurate in the SMILE group. The degree of myopia may change which ∆map is most accurate.

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Total keratometry for determination of true corneal power after myopic small-incision lenticule extraction

Abstract: This study compared TK and TCRP as measures of total corneal power after SMILE. TK is endorsed as a promising parameter for intraocular lens power calculation after SMILE.

Cited by 3 publications

References 13 publications

IOL Power Calculations and Cataract Surgery in Eyes with Previous Small Incision Lenticule Extraction

IOL Power Calculations and Cataract Surgery in Eyes with Previous Small Incision Lenticule Extraction

Intraocular lens power calculation using total keratometry and ray tracing in eyes with previous small incision lenticule extraction – A case series

Comparison of Corneal Power Difference Maps with Achieved Myopic Correction Using Scheimpflug Tomography After LASIK, PRK, and SMILE

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