Influence of axial length and corneal power on the astigmatic power of toric intraocular lenses

2013 ◽  
Vol 39 (12) ◽  
pp. 1900-1903 ◽  
Author(s):  
Giacomo Savini ◽  
Kenneth J. Hoffer ◽  
Michele Carbonelli ◽  
Pietro Ducoli ◽  
Piero Barboni
Keyword(s):  
Axial Length ◽  
Intraocular Lenses ◽  
Corneal Power

scholarly journals Intraocular lens power calculation for plus and minus lenses in high myopia using partial coherence interferometry

2021 ◽  
Author(s):  
Matthias Fuest ◽  
Niklas Plange ◽  
David Kuerten ◽  
Hannah Schellhase ◽  
Babac A. E. Mazinani ◽  
...  
Keyword(s):  
Axial Length ◽  
Absolute Error ◽  
Intraocular Lenses ◽  
Partial Coherence ◽  
Power Calculation ◽  
Partial Coherence Interferometry ◽  
Intraocular Lens Power Calculation ◽  
Hyperopic Shift ◽  
Lens Power ◽  
Lens Power Calculation

Abstract Purpose We assessed the accuracy of lens power calculation in highly myopic patients implanting plus and minus intraocular lenses (IOL). Methods We included 58 consecutive, myopic eyes with an axial length (AL) > 26.0 mm, undergoing phacoemulsification and IOL implantation following biometry using the IOLMaster 500. For lens power calculation, the Haigis formula was used in all cases. For comparison, refraction was back-calculated using the Barrett Universal II (Barrett), Holladay I, Hill-RBF (RBF) and SRK/T formulae. Results The mean axial length was 30.17 ± 2.67 mm. Barrett (80%), Haigis (87%) and RBF (82%) showed comparable numbers of IOLs within 1 diopter (D) of target refraction. Visual acuity (BSCVA) improved (p < 0.001) from 0.60 ± 0.35 to 0.29 ± 0.29 logMAR (> 28-days postsurgery). The median absolute error (MedAE) of Barrett 0.49 D, Haigis 0.38, RBF 0.44 and SRK/T 0.44 did not differ. The MedAE of Haigis was significantly smaller than Holladay (0.75 D; p = 0.01). All median postoperative refractive errors (MedRE) differed significantly with the exception of Haigis to SRK/T (p = 0.6): Barrett − 0.33 D, Haigis 0.25, Holladay 0.63, RBF 0.04 and SRK/T 0.13. Barrett, Haigis, Holladay and RBF showed a tendency for higher MedAEs in their minus compared to plus IOLs, which only reached significance for SRK/T (p = 0.001). Barrett (p < 0.001) and RBF (p = 0.04) showed myopic, SRK/T (p = 002) a hyperopic shift in their minus IOLs. Conclusions In highly myopic patients, the accuracies of Barrett, Haigis and RBF were comparable with a tendency for higher MedAEs in minus IOLs. Barrett and RBF showed myopic, SRK/T a hyperopic shift in their minus IOLs.

Intraocular lenses optic power calculation with seven formulas in short eyes

2021 ◽  
pp. 57-61
Author(s):  
K.B. Pershin ◽  
◽  
N.F. Pashinova ◽  
I.A. Likh ◽  
А.Y. Tsygankov ◽  
...  
Keyword(s):  
Axial Length ◽  
Mean Absolute Error ◽  
Optical Power ◽  
Absolute Error ◽  
Intraocular Lenses ◽  
Power Calculation ◽  
Retrospective Comparison ◽  
Monofocal Iol ◽  
The Mean ◽  
Axial Eye Length

Purpose. The choice of the optimal formula for calculating the IOL optical power in patients with an axial eye length of less than 20 mm. Material and methods. A total of 78 patients (118 eyes) were included in the prospective study. 1st group included 30 patients (52 eyes) with short eyes (average axial eye length of 19.60±0.42 (18.54–20.0) mm), 2nd group consisted of 48 patients (66 eyes) with a axial length 22.75±0.46 (22.0–23.77) mm. Various monofocal IOL models were used. The average follow-up period was 13 months. IOL optical power was calculated using the SRK/T formula, retrospective comparison – according to the formulas Hoffer-Q, Holladay II, Olsen, Haigis, Barrett Universal II and Kane. Results. In 1st group, the mean absolute error was determined for the formulas Haigis, Olsen, Barrett Universal II, Kane, SRK/T, Holladay II and Hoffer-Q (0.85, 0.78, 0.21, 0.17, 0.79, 0.73, 0.19 respectively). When comparing the formulas, significant differences were found for the formulas Hoffer-Q, Barrett Universal II and Kane in comparison with the formulas Haigis, Olsen, SRK/T and Holladay II (p<0.05) in all cases, respectively. In 2nd group, the mean absolute error was determined for the formulas Haigis, Olsen, Barrett Universal II, Kane, SRK/T, Holladay II and Hoffer-Q (0.15, 0.16, 0.23, 0.10, 0.19, 0.23, 0,29 respectively). In 2nd group, there were no significant differences between the studied formulas (p>0.05). Conclusion. This paper presents an analysis of data on the effectiveness of seven formulas for calculating the IOL optical power in short (less than 20 mm) eyes in comparison with the normal axial length. The advantage of the Hoffer-Q, Barrett Universal II and Kane formulas over Haigis, Holladay II, Olsen, and SRK/T is shown. Key words: cataract, hypermetropia, short eyes, calculation of the IOL optical power.

Accuracy of common IOL power formulas in 611 eyes based on axial length and corneal power ranges

2020 ◽  
pp. bjophthalmol-2020-315882
Author(s):  
Veronika Röggla ◽  
Achim Langenbucher ◽  
Christina Leydolt ◽  
Daniel Schartmüller ◽  
Luca Schwarzenbacher ◽  
...  
Keyword(s):  
Axial Length ◽  
Prediction Error ◽  
Absolute Error ◽  
Power Calculation ◽  
Corneal Power ◽  
Biometric Parameters ◽  
Iol Power Calculation ◽  
Iol Power ◽  
Median Absolute Error ◽  
Axial Eye Length

AimsTo provide clinical guidance on the use of intraocular lens (IOL) power calculation formulas according to the biometric parameters.Methods611 eyes that underwent cataract surgery were retrospectively analysed in subgroups according to the axial length (AL) and corneal power (K). The predicted residual refractive error was calculated and compared to evaluate the accuracy of the following formulas: Haigis, Hoffer Q, Holladay 1 and SRK/T. Furthermore, the percentages of eyes with ≤±0.25, ≤±0.5 and 1 dioptres (D) of the prediction error were recorded.ResultsThe Haigis formula showed the highest percentage of cases with ≤0.5 D in eyes with a short AL and steep K (90%), average AL and steep cornea (73.2%) but also in long eyes with a flat and average K (65% and 72.7%, respectively). The Hoffer Q formula delivered the lowest median absolute error (MedAE) in short eyes with an average K (0.30 D) and Holladay 1 in short eyes with a steep K (Holladay 1 0.24 D). SRK/T presented the highest percentage of cases with ≤0.5 D in average long eyes with a flat and average K (80.5% and 68.1%, respectively) and the lowest MedAE in long eyes with an average K (0.29 D).ConclusionOverall, the Haigis formula shows accurate results in most subgroups. However, attention must be paid to the axial eye length as well as the corneal power when choosing the appropriate formula to calculate an IOL power, especially in eyes with an unusual biometry.

Areal summed corneal power shift is an important determinant for axial length elongation in myopic children treated with overnight orthokeratology

2019 ◽  
Vol 103 (11) ◽  
pp. 1571-1575 ◽  
Author(s):  
Yin Hu ◽  
Canhong Wen ◽  
Zhouyue Li ◽  
Wenchen Zhao ◽  
Xiaohu Ding ◽  
...  
Keyword(s):  
Axial Length ◽  
Term Effect ◽  
Multivariate Linear Regression Analysis ◽  
Corneal Power ◽  
Power Shift ◽  
Long Term Effect ◽  
Study Participants ◽  
The Impact

BackgroundThe myopia control effect of orthokeratology (OK) varies among individuals. The variation might relate to the proposed ‘areal summation effect’ of lens-induced visual signals. The current study evaluated the areal summed corneal power shift (ASCPS) in myopic children treated with OK lenses and assessed whether the ASCPS achieved at early post-OK visit can predict the lens long-term effect on the axial length (AL) elongation.MethodsStudy participants were 130 myopic children treated with OK lenses (age range, 8 to 15 years) in a prospective study. Corneal topography and AL were measured at baseline and 1, 3, 6, 9 and 12 months after OK lens wear. The ASCPS was derived from corneal topographic measurements and defined as the change in the areal summed corneal relative refraction at the follow-up visit from baseline. The impact of the ASCPS achieved at the 1 month post-OK visit on the 12 months AL elongation was examined using multivariate linear regression analysis.ResultsBaseline age of the study participants was 11.8 ± 1.8 years and their mean spherical equivalent was −3.00±0.92 D. The ASCPS was 6.90±6.09 D*mm at the 1 month visit and remained stable throughout the follow-up period (p=0.5508, repeated-measures analysis of variance). Greater 1 month ASCPS was associated with slower AL elongation at the 12 months visit (β=−0.007, p=0.001).ConclusionsThe ASCPS achieved at early post-OK visit is predictive for the lens long-term effect on the myopic AL elongation. The parameter is potential in guiding the OK lens practice to slow down axial growth in myopic children.

Intraocular lenses optic power calculation with seven formulas in short eyes

2021 ◽  
pp. 37-40
Author(s):  
K.B. Pershin ◽  
◽  
N.F. Pashinova ◽  
I.A. Likh ◽  
А.I. Tsygankov ◽  
...  
Keyword(s):  
Axial Length ◽  
Mean Absolute Error ◽  
Optical Power ◽  
Absolute Error ◽  
Intraocular Lenses ◽  
Power Calculation ◽  
Group I ◽  
The Mean ◽  
Group Ii ◽  
Axial Eye Length

Purpose. The choice of the optimal formula for calculating the IOL optical power in patients with an axial eye length of less than 20 mm. Material and methods.A total of 78 patients (118 eyes) were included in theprospective study. Group I included 30 patients (52 eyes) with short eyes (average axial eye length of 19.60 ± 0.42 (18.54-20.0) mm), group II consisted of 48 patients (66 eyes) with a axial length (22.75 ± 0.46 (22.0-23.77) mm. Various monofocal IOL models were used. The average follow-up period was 13 months. IOL optical power was calculated using the SRK/T formula, retrospective comparison - according to the formulas Hoffer-Q, Holladay II, Olsen, Haigis, Barrett Universal II and Kane. Results. In group I, the mean absolute error was determined for the formulas Haigis, Olsen, Barrett Universal II, Kane, SRK / T, Holladay 2 and Hoffer-Q (0.85; 0.78; 0.21; 0.17; 0.79; 0.73; 0.19 respectively). When comparing the formulas, significant differences were found for the formulas Hoffer-Q, Barrett Universal II and Kane in comparison with the formulas Haigis, Olsen, SRK / T and Holladay II (p <0.05) in all cases, respectively. In group I, the mean absolute error was determined for the formulas Haigis, Olsen, Barrett Universal II, Kane, SRK / T, Holladay 2 and Hoffer-Q (0.15; 0.16; 0.23; 0.10; 0.19; 0.23; 0.29 respectively) In group II, there were no significant differences between the studied formulas (p> 0.05). Conclusion. This paper presents an analysis of data on the effectiveness of seven formulas for calculating the IOL optical power in short (less than 20 mm) eyes in comparison with the normal axial length. The advantage of the Hoffer-Q, Barrett Universal II and Kane formulas over Haigis, Holladay 2, Olsen, and SRK / T is shown. Key words: cataract; hypermetropia; short eyes; calculation of the IOL optical power.

scholarly journals Correlations among Refractive Error, Axial Length, and Corneal Power in Childhood

2018 ◽  
Vol 59 (5) ◽  
pp. 471
Author(s):  
Youn Gon Lee ◽  
Seung-Hee Baek ◽  
Hyun Taek Lim ◽  
Dae Hee Kim
Keyword(s):  
Refractive Error ◽  
Axial Length ◽  
Corneal Power
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