Academic literature on the topic 'Keratometry outcome'
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Journal articles on the topic "Keratometry outcome"
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Pereira, Arpitha. "Comparing the corneal curvatures obtained from three different keratometers-IOL Master, Bausch & Lomb Manual keratometer and TOPCON KR 8800 autokeratometer." International Eye Research 1, no. 1 (2020): 13–16. http://dx.doi.org/10.18240/ier.2020.01.03.
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AIM: To compare the corneal curvature and to investigate the agreement between three different keratometers. METHODS: In this prospective study, keratometry was performed using an IOL Master, a Bausch & Lomb manual keratometer and TOPCON KR-8800 autokeratometer on 252 eyes of patients recruited from camps for cataract surgery. The average keratometry values were recorded and compared. The agreements between the instruments were analyzed using the Bland Altman statistical method. The main outcome measure was average keratometry values.RESULTS: The mean corneal power was 44.62±1.52 D with the IOL Master, 44.60±1.52 D with the manual keratometer, and 44.46±1.53 D with the autokeratometer. The paired t test demonstrated a statistically significant difference in the mean corneal power between the IOL Master and manual keratometer (P=0.001), IOL Master and autokeratometer (P<0.0001), autokeratometer and manual keratometer (P<0.0001). The 95% limits of agreement (LoA) of the IOL Master and manual keratometer were -0.22 to 0.26; IOL Master and autokeratometer were -0.24 to 0.55; autokeratometer and manual keratometer were -0.30 to 0.57 as shown in the Bland-Altman plot. CONCLUSION: Keratometry data obtained with different instruments may not be interchangeable, a fact that has important implications for cataract surgeons with respect to both surgical planning and outcomes auditing.
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Magar, JB Ale. "Comparison of the corneal curvatures obtained from three different keratometers." Nepalese Journal of Ophthalmology 5, no. 1 (2013): 9–15. http://dx.doi.org/10.3126/nepjoph.v5i1.7815.
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Introduction: Keratometry forms an important component of the biometry for a calculation of the intraocular lens power and selecting a contact lens’ parameters. Objective: To investigate the agreement between three different keratometers commonly used in an ophthalmology clinic. Materials and methods: In this prospective study, keratometry was performed using an IOL Master (IM), a manual keratometer (Man) and a autokeratometer (Top) in twenty five eyes of thirteen volunteer subjects. The average keratometry values and corneal astigmatism (J180 and J45 components) were computed and compared. The agreements between the instruments were analysed using the Bland Altman statistical method. The main outcome measures are average keratometry values and corneal astigmatism. Results: The mean of average keratometry values obtained from the IOL Master, manual keratometry and autokeratometry were 44.388 ± 1.430, 44.297 ± 1.425 and 44.220 ± 1.497 D, respectively. The mean difference in the average keratometry between the instruments were 0.31 ± 0.09 for IM and Man (p = 0.012), 0.14 ± 0.17 for IM and Top (p = < 0.001) and 0.29 ± 0.77 for Man and Top (p = 0.26). The mean differences in the J180 component of astigmatism were: 0.02 ± 0.11 for IM and Man, 0.02 ± 0.09 for IM and Top, and - 0.01 ± 0.11 for Man and Top. Similarly, for the J45 component, the mean differences were 0.02 ± 0.12 for IM and Man, 0.01 ± 0.13 for IM and Top and - 0.02 ± 0.10 for Man and Top. Conclusion: Average keratometry values obtained from different instruments vary significantly. The IOL Master consistently over-estimated the corneal power compared to the manual and the autokeratometer. All three instruments provided similar estimation of the corneal astigmatism. Nepal J Ophthalmol 2013; 5(9):9-15 DOI: http://dx.doi.org/10.3126/nepjoph.v5i1.7815
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Mohamed Mostafa, Engy. "Effect of Flat Cornea on Visual Outcome after LASIK." Journal of Ophthalmology 2015 (2015): 1–7. http://dx.doi.org/10.1155/2015/794854.
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Purpose. To evaluate the effect of preoperative and postoperative keratometry on the refractive outcome after laser in situ keratomileusis (LASIK) for moderate and high myopia.Methods. Records of 812 eyes (420 patients) with myopia ≥−6 D who had LASIK at Sohag Laser Center, Egypt, from January 2010 to November 2013, were retrospectively analyzed. Main outcome measures were postoperative corrected distance visual acuity (CDVA), postoperative spherical equivalence, and postoperativeQfactor.Results. LASIK was performed in 812 eyes (mean age21.8±5.2years). Patients were grouped according to the degree of preoperative myopia into three groups: Group 1, −6 D to −7.9 D; Group 2, −8 to −9.9 D; and Group 3, −10 to −12 D. The refractive outcome among the different myopia groups was stratified by pre- and postoperative keratometry. A trend toward greater undercorrection was noted in eyes with preoperative keratometry <43.5 D compared with those with steeper keratometry >46 D in all myopia groups. The undercorrection was also noted in postoperative keratometry groups <35 D.Conclusions. Preoperative and postoperative keratometry appeared to influence the refractive outcome especially in high myopic eyes.
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Alfaqawi, Fadi, Luca Pagano, Esmaeil M. Arbabi, et al. "Cataract surgery has minimal effect on corneal shape." BMJ Open Ophthalmology 10, no. 1 (2025): e001920. https://doi.org/10.1136/bmjophth-2024-001920.
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PurposeTo quantify the effect of cataract surgery on cornea shape.MethodsPatients undergoing cataract surgery with standardised 2.75 mm surgical incisions at 110 degrees with a side port at 50 degrees were included. Repeat biometric measurements were taken before surgery and at 6 weeks on both operated and unoperated fellow eyes. Data were transformed into Long’s formalism for analysis. Device-specific measurement error was determined. The main outcome measure was the change in keratometry taking into account the change in keratometry of the unoperated fellow eye. Secondary outcome measures included the variability introduced due to location of the incision.Results132 patients were included. The mean change in keratometry of the operated eye was −0.23@111/+0.21@21 (95% CI −1.43@122/+0.04@32 to +1.04@135/+0.30@45). The flattening effect of the surgical incision was greater and more variable than the steepening effect (p<0.01), particularly if the incision was in the flat meridian. Coupling, defined as ratio of the keratometric change in the preoperative meridians of K2 and K1, varied from 0.91 (SD 2.31) for eyes with an incision in the steep meridian, 0.75 (SD 1.81) for an incision in the flat meridian to 0.28 (SD 2.06) when the incision was made in a neutral meridian.ConclusionCataract surgery has a slightly greater flattening than steepening effect on corneal shape. Although the effects are very small and variable with incomplete coupling, it is preferable to place the incision in the steep meridian. Greater emphasis, however, should be placed on eye-specific factors, such as biometry, or patient-related factors to optimise refractive outcomes.
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Bhatta, Sabitri, Sagun Narayan Joshi, Madhu Thapa, Suresh Awasthi, Gauri Shankar Shrestha, and Niraj Dev Joshi. "Prediction and Estimation of Postoperative Refractive Error in Phacoemulsification: Using Ultrasound A-Scan and Intra Ocular Lens Master." Journal of Nepal Health Research Council 22, no. 03 (2024): 494–501. https://doi.org/10.33314/jnhrc.v22i03.4854.
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Background: This study aims to predict and estimate the postoperative refractive outcome in participants undergoing phacoemulsification using IOL Master and A-scan biometry.Methods: A cross-sectional study was done where ninety eyes of 90 participants undergone phacoemulsification using SRK/T formula were included in longitudinal research. Each participant underwent axial length (AL) measurement by IOL Master and A-scan, and keratometry reading (k- reading) by manual TOPCON keratometer and automated keratometer on IOL master for IOL power calculation. All the pre-operative measurements between A-scan and IOL master and two keratometers were compared using paired-t tests. The four-week postoperative refractive error was estimated using univariate analysis and its prediction was compared with the ocular biometry parameters using quadratic regression.Results: Preoperative findings were higher for AL and ACD by IOL master and A-scan (0.27±0.14mm; p<0.001, 0.14±0.31mm, p<0.001) respectively. The AL and K-reading were found to be strong predictors of IOL power calculation (β = -1.07; p<0.001, β = 0.75; p<0.001), respectively. The AL, K-reading were found to be strong predictors for four-week postoperative refractive error (β = -1.563; p = 0.012, β = 1.052; p = 0.012) where postoperative error was found to be higher (F = 7.521, p<0.001) in A-scan than IOL Master. For K-reading, the two keratometer’s and for AL by A-scan and IOL Master’s level of agreement (95% LoA) was comparable (-0.15 to 0.12mm and -0.01 to 0.54mm). Conclusions: IOL Master is more reliable for ocular biometry and minimizes postoperative refractive error.Keywords: Axial length; intraocular lens power; keratometry-reading; refractive error estimation; postoperative refractive error.
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Luna, Mahfuja Khanam, S. Faisal Ahmed, Syeed Mehbub Ul Kadir, Arup Ratan Ray, and Somir Hossain. "Residual astigmatism following cataract surgery." Anwer Khan Modern Medical College Journal 13, no. 1 (2021): 42–46. http://dx.doi.org/10.3329/akmmcj.v13i1.64728.
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Objective: To determine the amount of residual astigmatism following cataract surgery.
 Materials and methods: A hospital based observational study was conducted in a tertiary eye hospital, Bangladesh during the period of July, 2013 to June, 2014. Patients was selected for the study who diagnosed as ARC with variable amount of astigmatism (1.5 to 3.5D), and excluded any other ocular pathology or history of previous ocular surgery. Phacoemulsification with PC Toric IOL implantation in all cases. Auto refracto-keratometer was done Preoperative and postoperatively for assessing the astigmatism. Main outcome measured were included preoperative uncorrected visual acuity, postoperative uncorrected visual acuity on 1stPOD, after 1 week and 1month, Preoperative keratometry, Preoperative astigmatism, Postoperative uncorrected keratometry on 1st POD, after 1 week and 1month, Postoperative uncorrected astigmatism on 1stPOD, after 1 week and 1month
 Results: 30 eyes of 28 patients were assessed in this study. Due to clear corneal incision during phacoemulsification, the steep meridian became flat significantly from pre-operative keratometry 44.329±1.473D (mean±SD) to 30thpost operative keratometry 43.971±1.431D (mean±SD) having p<0.001. On the other-hand the flat meridian became steeper from pre-operative keratometry 42.225±1.471D (mean±SD) to 30thpost operative keratometry 42.421±1.501D (mean±SD) having p<0.001. Preoperative mean astigmatism [Mean±SD] was 2.104±0.319D, after the first postoperative day, mean astigmatism decreased to 0.954±0.494D with p<0.01, and finally after 1 Month there was significant reduction of pre-operative astigmatism to 0.583±0.413D with p<0.0001. So, the mean pre-operative astigmatism decreased significantly in the successive post-operative days.
 Conclusion: Toric Intraocular lens implantation in phacoemulsification surgery can correct pre-existing corneal astigmatism significantly after one month of surgery.
 AKMMC J 2022; 13(1) : 42-46
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Dr., Shakeel Ahmad Dr. Samra Kanwal Dr. Muhammad Haroon Haider. "THE OUTCOME OF USING (5.5 MM) SELF-SEALING LIMBAL INCISION FOR EYES WITH (1.5 – 3.0) D PRE-EXISTING ASTIGMATISM ON THE STEEPEST MERIDIAN." INDO AMERICAN JOURNAL OF PHARMACEUTICAL SCIENCES 05, no. 08 (2018): 8187–91. https://doi.org/10.5281/zenodo.1407498.
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<strong><em>Objective: </em></strong><em>The research objective is to calculate keratometry results of a 5.5 mm self-sealing incision in eyes, having astigmatism pre-existed, on the sharpest/steepest meridian.</em> <strong><em>Methodology: </em></strong><em>A prospective researched method was observed upon thirty-five eyes having astigmatism (with or against 1.5 to 3 D) pre-existed at Service Hospital, Lahore (October 2016 September 2017). A 1.5 mm incision, 120 degrees approximate separation each, was used for the performance of Bi-manual phaco. A third self-sealing limbal incision which was created on the steepest meridian was used for the implantation of IOL. Before operating, keratometry reading was taken for the assessment. After twelve weeks of operation, automated keratometry was recorded.</em> <strong><em>Results: </em></strong><em>Average pre-existing reduction against the rule astigmatism was 1.15 with SD equal to 0.33 and with the rule astigmatism was 1.47 with SD equals to 0.32.</em> <strong><em>Conclusions: </em></strong><em>Our research outcome reports that by placing a third 5.5 mm incision and determining the steepest meridian, the possibility of low astigmatic outcomes is achievable with/against the rule of astigmatism pre-existed in the eyes.</em> <strong>Keywords: </strong><em>Steepest meridian (SM), </em><em>Pre-existing astigmatism (PEA), Self-sealing Limbal Incision (SSLI), Keratometry outcome, Limbal Incision (LI).</em>
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Dong, Jing, Yaqin Zhang, and Xiaogang Wang. "Calculation of Toric Intraocular Lens Power with the Barrett Calculator and Data from Three Keratometers." Journal of Tropical Medicine 2021 (August 20, 2021): 1–6. http://dx.doi.org/10.1155/2021/7712345.
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Aim. To investigate the interdevice agreement for differences in toric power calculated using data on anterior corneal astigmatism obtained with corneal topography/ray-tracing aberrometry (iTrace), partial coherence interferometry (IOLMaster 500), and Scheimpflug imaging (Pentacam). Methods. The analysis included 101 eyes (101 subjects) with regular astigmatism. The main outcome measures were corneal cylinder power, axis of astigmatism, and keratometry values. Toricity and toric IOL power were calculated using the online Barrett toric calculator. Interdevice agreement for measurement and calculation was assessed using a paired sample t-test and a nonparametric test. Results. Significant interdevice differences were noted in the magnitude of astigmatism and flat, steep, and mean keratometry values between iTrace and IOLMaster (all P < 0.01 ); in flat, steep, and mean keratometry values (all P < 0.001 ) but not in the magnitude of astigmatism ( P = 0.325 ) between iTrace and Pentacam; and in the magnitude of astigmatism and steep and mean keratometry values (all P < 0.01 ) but not in flat keratometry values ( P = 0.310 ) between IOLMaster and Pentacam. The toric IOL power calculated using data from the three devices showed the following trend: iTrace > IOLMaster (0.49 ± 0.36, P < 0.001 ) and Pentacam (0.39 ± 0.42, P < 0.001 ) and Pentacam was <IOLMaster (−0.10 ± 0.39, P = 0.009 ). There were differences in toricity calculated using data from the three devices ( P = 0.004 ). Conclusions. Differences in toric IOL power and toricity calculated using anterior keratometry data from iTrace, IOLMaster 500, and Pentacam should be noted in clinical practice.
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Olsen, Hanne, Niels Ehlers, and Jesper Ø. Hjortdal. "Value of intraoperative keratometry in predicting outcome of radial keratotomy." Acta Ophthalmologica Scandinavica 75, no. 4 (2009): 398–400. http://dx.doi.org/10.1111/j.1600-0420.1997.tb00397.x.
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Levy, Issac, Ritika Mukhija, and Mayank A. Nanavaty. "Corneal Allogenic Intrastromal Ring Segments: A Literature Review." Journal of Clinical Medicine 14, no. 4 (2025): 1340. https://doi.org/10.3390/jcm14041340.
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Background: Corneal allogenic intrastromal ring segments (CAIRSs) offer a novel, biocompatible alternative to synthetic intracorneal ring segments (ICRSs). This review aims to evaluate the clinical outcomes of CAIRS. Methods: Inclusion criteria were studies with a minimum of 20 eyes and six months of follow up. The primary outcome measure was uncorrected distance visual acuity (UDVA). The secondary outcomes were a change in corrected distance visual acuity (CDVA), spherical equivalent (SE), mean keratometry (K-mean), maximum keratometry (K-max), K1, K2, and pachymetry. Results: The primary outcome UDVA improved from 0.83 ± 0.15 to 0.40 ± 0.08 logMAR (p = 0.01), while CDVA improved from 0.52 ± 0.22 to 0.19 ± 0.09 logMAR (p = 0.01). K-max decreased from 57.8 ± 1.09 D to 53.57 ± 2.66 D (p < 0.01), and K-mean reduced from 49.27 ± 0.28 D to 45.30 ± 1.46 D (p < 0.01). An average of 84.92% ± 11.4% of eyes had an improvement in UDVA. No major complications or significant visual acuity deterioration were reported. Conclusions: CAIRSs serve as an alternative to synthetic ICRSs and even corneal transplantation in some cases. They represent a safe, effective, and biocompatible promising advancement in corneal ectasia management to improve visual acuity and corneal topography with minimal complications.
Dissertations / Theses on the topic "Keratometry outcome"
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Rowjee, Taruna. "A retrospective analysis of the outcomes in visual acuity and keratometry readings after corneal collagen crosslinking in keratoconus." Thesis, 2017. http://hdl.handle.net/10539/23205.
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A dissertation submitted to the Faculty of Health Sciences, University of the Witwatersrand, in the fulfillment of the requirements for the degree of Master of Medicine in Ophthalmology.
Johannesburg, February 2017<br>Purpose: To evaluate if corneal collagen crosslinking carried out on patients with keratoconus, slows down or halts the progression of keratoconus. To determine which group of keratoconus patients benefited most from the procedure.
Methods: A retrospective record review of 41 eyes of 29 patients. Visual acuity and keratometry measurements were recorded for the involved eye pre-crosslinking and at 3 months and 6 months post-crosslinking. A comparison of these variables pre-crosslinking and at 6 months post-crosslinking was made to determine if there was a flattening of corneal curvature (keratometry readings) and an improvement in visual acuity.
Patients were further divided into 3 groups of keratoconus, based on their keratometry readings (measured in diopters): mild keratoconus (≤47 diopters), moderate keratoconus (48 – 54 diopters) and advanced keratoconus (≥55 diopters), to determine which group of keratoconus had the best keratometry reduction readings.
Results: After crosslinking took place on 41 eyes, the UnVA of 16(39%) eyes showed an improvement at 6 months, 17(41%) eyes showed no change and
8(20%) eyes showed a decrease in UnVA at 6 months, compared to pre-CXL values.
For BCVA, 12(29%) eyes showed an improvement at 6 months, 18(44%) eyes showed no change and 11(27%) eyes showed a decrease in BCVA at 6 months, compared to pre-CXL values.
Keratometry readings however showed that 23(56%) eyes had an average flattening of corneal curvature readings of 0.7 D and the remaining 18(44%) eyes showed more steepening (worsening) of the corneal curvature readings of 0.9 D after 6 months post-CXL.
30(73%) eyes had mild keratoconus, 7(17%) had moderate keratoconus and 4(10%) had advanced keratoconus.
19 of the 30 eyes in the mild keratoconus group (73%) showed an average flattening of corneal curvature of 0.6 D. 4 of the 7 eyes in the moderate keratoconus group (17%) showed an average flattening of corneal curvature of 0.7 D. All 4 patients in the advanced group (10%) had steepening (worsening) of their corneal curvatures with an average of 1.2 D.
Conclusion: Corneal collagen crosslinking performed on keratoconus patients at least halts the progress of keratoconus. 6 months after CXL most patients showed minimal change from pre-CXL to 6 months in both visual acuity and keratometry. However a longer follow up period and larger sample size is needed to determine if vision and keratometry readings can improve significantly.<br>MT2017
Book chapters on the topic "Keratometry outcome"
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Olsen, Thomas. "ELP Estimation." In Intraocular Lens Calculations. Springer International Publishing, 2024. http://dx.doi.org/10.1007/978-3-031-50666-6_34.
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AbstractThe rationale of the “thin-lens” IOL power calculation formula and the definition of the estimated lens plane (ELP) are explained. Because the ELP is often back-calculated from the observed outcome the ELP is different from the physical position of the IOL. The exact manner by which the ELP is predicted varies between the various formulas, which may take the axial length, the K-reading, the anterior chamber depth, the lens thickness, and other parameters to increase the predictability. However, care should be taken when dealing with post-LASIK eyes, keratoconus, or other unusual eyes. Unlike the “thin-lens” ELP-formulas, the Olsen formula utilizes the C-constant concept, predicting the physical position of the IOL from the position and anatomy of the crystalline lens. Finally, an error propagation model is presented predicting the total IOL prediction error as a function of errors in the ELP prediction (largest source), the keratometry, the axial length reading, and other sources of error.
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Fam, Han Bor. "Outcomes Review of Intraocular Lens Power Calculation Formulas." In Intraocular Lens Calculations. Springer International Publishing, 2024. http://dx.doi.org/10.1007/978-3-031-50666-6_33.
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AbstractThis chapter analizes the published outcomes of intraocular lens (IOL) power calculation formulas. A modified version of the formula performance index (PI) proposed by Prof. Haigis is presented. This index ranks formulas accuracy based on several parameters, including the standard deviation (SD) of the prediction error, the median absolute error (MedAE) , the relationship between the prediction error (PE) and axial length (AL) and the percentage of eyes with a prediction error within ±1.00 D. Modifications include the mean absolute error, (MAE) the percentage of eyes with a prediction error within ±0.50 D, and the relationship between the prediction error and keratometry (K). A further version of the PI, specifically designed for subgroup analysis, is also presented.The data of 17 studies (including eyes with any AL) are presented, and formulas are compared by means of the PI. A similar analysis is presented separately for short, medium, and long eyes, as well as for eyes with flat and steep corneas, shallow and deep anterior chambers (ACD) and for eyes with a target refraction other than emmetropia.
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Savini, Giacomo, and Adi Abulafia. "Toric Calculations." In Intraocular Lens Calculations. Springer International Publishing, 2024. http://dx.doi.org/10.1007/978-3-031-50666-6_62.
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AbstractOlder toric calculators were limited by the use of the keratometric astigmatism (with no information about posterior corneal curvature) and the adoption of a fixed ratio between the cylinder at the IOL plane and the cylinder at the corneal plane. A discussion about these issues that have been solved by newer calculators is provided along with a brief introduction to the influence of IOL tilt on the refractive outcomes of toric IOLs. The Abulafia-Koch, Barrett, Barrett True-K, EVO, Goggin, Holladay, Johnson & Johnson, Kane, Næser-Savini, Rayner, and Zeiss toric calculators are described. According to the published studies, the percentage of eyes with an absolute prediction error of the cylinder within 0.50 D ranges between 55 and 79% with calculators estimating Total Corneal Astigmatism (TCA), whereas it is close to 40% with calculators using measured TCA and around 25–30% with calculators using Keratometric Astigmatism (KA).
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Aramberri, Jaime, Giacomo Savini, and Kenneth J. Hoffer. "IOL Power Calculation After Corneal Refractive Surgery." In Intraocular Lens Calculations. Springer International Publishing, 2024. http://dx.doi.org/10.1007/978-3-031-50666-6_65.
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AbstractIntraocular lens (IOL) power calculation is affected by the effect of any previous corneal refractive surgery. In this chapter, an extensive analysis of the different sources of error and the correspondent solutions is performed. Corneal shape change and keratometric error are the main contributors to the final refractive error. Incorrect IOL position estimation is another potential cause of error in determined formulas. New corneal tomographers and the use of a correct calculation method will improve the outcomes avoiding the commission of significant errors. A classification of the published methods to be used in these cases with their performance data will allow the surgeon to select the best option in each particular case.