scholarly journals The comparative study of applanation and optical coherence biometry methods for the intra ocular lens power calculation

2018 ◽  
Vol 6 (03) ◽  
pp. 01-08
Author(s):  
Mahesh Chandra ◽  
Jitendra Singh ◽  
Mahesh Chandra Agarwal ◽  
Govind Singh Titiyal
Keyword(s):  
Comparative Study ◽  
Axial Length ◽  
Age Groups ◽  
Power Calculation ◽  
Optical Coherence ◽  
Perfect Agreement ◽  
Iol Power Calculation ◽  
Significant Difference ◽  
Iol Power ◽  
Lens Power

Purpose: To compare applanation biometry (A-Scan) and optical coherence biometry (AL-Scan) methods for IOL power calculation based on Axial Length and post operative refractive outcome. Methodology: Prospective and Interventional Randomized Comparative Study, Sample size of 400, studied under two sub groups, for Axial Length readings and IOL power calculation by A-Scan (Biomedix) and AL-Scan (Nidek). Keratometry readings are taken only by AL-Scan.Results: Mean ± St. dev. of A.L. measured by App. Biometry was low (22.79 ± 0.9 mm) than Opt. Coh. Biometry (23.16 ± 0.78 mm) to be significant (P= .0001). Mean ± St. dev. IOL power was higher (21.75 ± 2.1D) than App. Biometry (20.88 ± 1.59 D) to be significant (P= 0.0001). Mean ± St. dev. of refractive status for Myopia is higher -0.97 ± 0.53 by App. Biometry than Opt. Coh. Biometry -0.5 ± 0.19, to be significant (P= 0.0001) and Mean ± St.dev. for Hyperopia is higher 0.98 ± 0.59 by App. Biometry than Opt. Coh. Biometry 0.46 ± 0.18, to be significant (P= 0.0001). Bland–Altman plots showed perfect agreement between both methods regarding A.L. and calculated IOL power. Further subgroup analysis revealed a statistically significant difference in different age groups and types of cataract for Posterior Sub capsular cataract alone and Nuclear Sclerosis with Posterior Sub capsular cataract (P= 0.001). Conclusion: There is significant difference between App. and Opt. Coh. Biometry; however, certain situations of Cataract is demanding mandatory role of App. Biometry.

scholarly journals Accuracy of Intraocular Lens Power Calculation Using Anterior Chamber Depth from Two Devices with Barrett Universal II Formula

2019 ◽  
Vol 2019 ◽  
pp. 1-5
Author(s):  
Hannah Muniz Castro ◽  
Audrey X. Tai ◽  
Samuel J. Sampson ◽  
Matthew Wade ◽  
Marjan Farid ◽  
...  
Keyword(s):  
Anterior Chamber ◽  
Anterior Chamber Depth ◽  
Absolute Error ◽  
Power Calculation ◽  
Intraocular Lens Power Calculation ◽  
Iol Power Calculation ◽  
Significant Difference ◽  
Iol Power ◽  
Retrospective Comparative Study ◽  
Lens Power

Purpose. To compare the preoperative measurements of the anterior chamber depth (ACD) by the IOLMaster and Catalys; additionally, to compare the accuracy of the IOL power calculated by the Barrett Universal II formula using the two different measurements. Setting. University of California, Irvine, Gavin Herbert Eye Institute in Irvine, California. Design. Retrospective comparative study. Methods. This study included 144 eyes of 90 patients with a mean age of 72.0 years (range 40.8 to 92.1 years) that underwent femtosecond laser-assisted cataract surgery using Catalys. Preoperative measurements of ACD were taken by the IOLMaster and Catalys. Manifest refraction and refractive spherical equivalent were measured 1 month postoperatively. Expected refractive results were compared with actual postoperative refractive results. Results. The correlation between the ACD values from the two devices was good (r = 0.80). The Catalys ACD measurements yielded a larger ACD compared to the IOLMaster, with a mean difference of 0.22 mm (P<0.0001). The correlation between the postoperative and predicted RSE of the implanted IOL power was excellent (r = 0.96). There was no statistically significant difference between the mean absolute error derived from the IOLMaster, 0.37 diopter (D) ± 0.34 (SD), and the Catalys, 0.37 ± 0.35 D (P=0.50). Conclusions. The Catalys biometry yielded a significantly larger ACD value than the IOLMaster. This difference in ACD value, however, did not reflect in a statistically significant difference in IOL power calculation and refractive prediction error using the Barrett Universal II Formula.

scholarly journals Accuracy of intraocular lens power calculation in pediatric cataracts with less than a 20 mm axial length of the eye

2014 ◽  
Vol 6 (1) ◽  
pp. 56-64 ◽  
Author(s):  
Purushottam Joshi ◽  
Raman Mehta ◽  
Suma Ganesh
Keyword(s):  
Axial Length ◽  
Prediction Error ◽  
Power Calculation ◽  
Pediatric Cataract ◽  
Intraocular Lens Power Calculation ◽  
Iol Power Calculation ◽  
Intraocular Lens Power ◽  
Iol Power ◽  
The Absolute ◽  
Lens Power

Introduction: Selection of an appropriately-powered IOL is a complex issue, especially in eyes with an axial length of less than 20 mm in pediatric cataract. Objective: To assess the accuracy of IOL power calculation formulae in pediatric cataracts in eyes with an axial length of less than 20 mm. Materials and methods: The records of children less than 15 years old with congenital cataract who had undergone primary IOL implantation were analyzed. Main outcome measures: The variables studied were axial length, keratometric values and the prediction error. The data were analyzed for prediction error determination using the SRK II, SRK T, Holladay 1 and Hoffer Q IOL power calculation formulae. The formula that gave the best prediction error was identified. Results: Twenty-eight eyes of 19 children were included in the study. The absolute prediction error was found to be 1.84 ± 2.09 diopters (D) with SRK II, 2.93±3.55D with SRK T, 3.63±4.06D with Holladay 1, and 4.83±5.02D with Hoffer Q. The number of eyes with the absolute prediction error within 0.5 D was 6 (21.42%) with SRK II, 4 (14.28%) with SRK T, 1 (3.57%) with Holladay 1, and 3 (10.71%) with Hoffer Q. The absolute prediction error with SRK II formula was significantly better than that with other formulae (P < .001). The axial length influenced the absolute prediction error with Hoffer Q formula (P = 0.04). The mean keratometry influenced the prediction error with SRK T formula (P = 0.02), Holladay 1 formula (P = 0.02) and Hoffer Q formula (P = 0.02). Conclusion: Although the absolute prediction error tends to remain high with all the present IOL power calculation formulae, SRK II was the most predictable formula in this study. DOI: http://dx.doi.org/10.3126/nepjoph.v6i1.10773 Nepal J Ophthalmol 2014; 6 (2): 56-64

scholarly journals Post Cataract Surgery Refractive Error in Myopic Patients Using SRK/T Versus Holladay 1 Formula for IOL Power Calculation

2019 ◽  
Vol 34 (2) ◽  
Author(s):  
Sidra Anwar, Atif Mansoor Ahmad, Irum Abbas, Zyeima Arif
Keyword(s):  
Intraocular Lens ◽  
Refractive Error ◽  
Axial Length ◽  
Power Calculation ◽  
Mean Error ◽  
Iol Power Calculation ◽  
Group A ◽  
Iol Power ◽  
The Mean ◽  
Group B

Purpose: To compare post-operative mean refractive error with SandersRetzlaff-Kraff/theoretical (SRK-T) and Holladay 1 formulae for intraocular lens (IOL) power calculation in cataract patients with longer axial lengths. Study Design: Randomized controlled trial. Place and Duration of Study: Department of Ophthalmology, Shaikh Zayed Hospital Lahore from 01 January 2017 01 January, 2018. Material and Methods: A total of 80 patients were selected from Ophthalmology Outdoor of Shaikh Zayed Hospital Lahore. The patients were randomly divided into two groups of 40 each by lottery method. IOL power calculation was done in group A using SRK-T formula and in group B using Holladay1 formula after keratomery and A-scan. All patients underwent phacoemulsification with foldable lens implantation. Post-operative refractive error was measured after one month and mean error was calculated and compared between the two groups. Results: Eighty cases were included in the study with a mean age of 55.8 ± 6.2 years. The mean axial length was 25.63 ± 0.78mm, and the mean keratometric power was 43.68 ± 1.1 D. The mean post-operative refractive error in group A (SRK/T) was +0.36D ± 0.33D and in group B (Holladay 1) it was +0.68 ± 0.43. The Mean Error in group A was +0.37D ± 0.31D as compared to +0.69D ± 0.44D in group B. Conclusion: SRK/T formula is superior to Holladay 1 formula for cases having longer axial lengths. Key words: Phacoemulsification, intraocular lens power, longer axial length, biometry.

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.

scholarly journals Accuracy of intraocular lens power calculation formulas in a steep cornea: A case report

2021 ◽  
pp. 29-33
Author(s):  
Ehab M Ghoneim ◽  
Ahmed A Hassaan
Keyword(s):  
Intraocular Lens ◽  
Power Calculation ◽  
Intraocular Lens Power Calculation ◽  
Iol Power Calculation ◽  
Intraocular Lens Power ◽  
Manifest Refraction ◽  
Iol Power ◽  
Lens Power ◽  
The Right ◽  
Lens Power Calculation

There is no enough knowledge about the accuracy of intraocular lens (IOL) power calculation formulas in steep corneas. This study may be the first one that compares the accuracy of the SRK II formula with Holladay1, Hoffer Q and Haigis formulas in steep corneas. We reported a case of a 60-year-old female, with a cataract in the left eye and with a steep cornea. We used the modern formulas; Holladay1, Hoffer Q and Haigis. The result (+7.0D) was unexpected compared to the manifest refraction and to the IOL power calculated in the right eye using the same formulas which was (+17.0D). We implanted (+12.0D) Sensar 1-piece IOL depending on our clinical experience. The post-operative refraction was (+0.00/-1.75axis106). Postoperative, we used the patient data to find the best formula in this case. We found that the SRK II (A118) result was (+11.5D) and thus this formula was the most accurate in this case. Keywords: SRK II; Holladay1; Hoffer Q; Haigis

scholarly journals Effects on IOL Power Calculation and Expected Clinical Outcomes of Axial Length Measurements Based on Multiple vs Single Refractive Indices

2020 ◽  
Vol Volume 14 ◽  
pp. 1511-1519
Author(s):  
H John Shammas ◽  
Maya C Shammas ◽  
Renu V Jivrajka ◽  
David L Cooke ◽  
Richard Potvin
Keyword(s):  
Clinical Outcomes ◽  
Axial Length ◽  
Refractive Indices ◽  
Power Calculation ◽  
Iol Power Calculation ◽  
Length Measurements ◽  
Iol Power

Accuracy of a New Swept-Source Optical Coherence Tomography Biometer for IOL Power Calculation and Comparison to IOLMaster

2017 ◽  
Vol 33 (10) ◽  
pp. 690-695 ◽  
Author(s):  
Giacomo Savini ◽  
Kenneth J. Hoffer ◽  
H. John Shammas ◽  
Jaime Aramberri ◽  
Jinhai Huang ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Power Calculation ◽  
Optical Coherence ◽  
Swept Source ◽  
Iol Power Calculation ◽  
Iol Power

Comparison of accuracy of different intraocular lens power calculation methods using artificial intelligence

2021 ◽  
pp. 112067212199472
Author(s):  
Gabor Nemeth ◽  
Adam Kemeny-Beke ◽  
Laszlo Modis
Keyword(s):  
Artificial Intelligence ◽  
Intraocular Lens ◽  
Power Calculation ◽  
Intraocular Lens Power Calculation ◽  
Iol Power Calculation ◽  
Iol Power ◽  
The Mean ◽  
Lens Power ◽  
Similar Accuracy ◽  
The Hill

Purpose: To assess the accuracy of the intraocular lens (IOL) power calculation based on three methods using artificial intelligence (AI) and one formula using no AI. Methods: During cataract surgery on 114 eyes, one type of IOL was implanted, calculated with the Hill-RBF 2.0 method. The theoretical postoperative refractions were calculated using the Kane and the Pearl-DGS methods and a vergence based formula (Barrett Universal II, BUII). The differences between the manifest and objective postoperative refractions and the predicted refractions were calculated. The percentage of eyes within ±0.5 D and ±1.0 D prediction error (PE), the mean, and the median absolute errors (MAE and MedAE) were also determined. Results: The mean age of the patients was 69.48 years; the axial length was between 21.19 and 25.39 mm. The number of eyes within ±0.5/±1.0 D PE was 96/108 (84.21%/94.73%) using the Hill-RBF 2.0 method, 92/107 (80.70%/93.85%) with the Kane method, 91/107 (79.82%/93.85%) with the Pearl-DGS method, and 91/106 (79.82%/92.98%) with the BUII formula, using subjective refraction. With objective refractometric data, PEs were within ±0.5 D in 88 (77.19%), 83 (72.80%), 82 (71.92%), and 80 (70.17%) cases (Hill-RBF, Kane, Pearl-DGS, BUII, respectively). MAE and MedAE were also best with the Hill-RBF 2.0 method (0.3 D; 0.18 D). Conclusion: Better accuracy of PE might be obtained by the Hill-RBF 2.0 method compared with BUII. The Kane and Pearl-DGS methods showed similar accuracy when compared with BUII.

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