Comparison of Biometric Values and Intraocular Lens Power Calculations Obtained by Ultrasound and Optical Biometry

Abstract This study sought to compare the biometric values and intraocular lens (IOL) power obtained by standard ultrasound and optical biometry. We examined 29 eyes in preparation for cataract surgery. None of the patients had refractive surgery or corneal anomaly. In all patients, the horizontal and vertical refractive power of the cornea was determined using a keratometer (Bausch&Lomb). The axial length of the eye was determined via A-scan ultrasound (BVI-compact-V-plus) using Hollady’s formula. The IOL power and complete biometric measurements were obtained via an IOL Master-500-Zeiss using the Hollady-2 formula. All obtained values were compared and analysed using the statistical program SPSS 20. The average age of treated patients was 71.21±1.68 years. In 16 patients with dense cataracts (55.17%), it was not possible to determine the IOL power by optical biometry. Optical biometry obtained significantly increased axial length values of 24.04±0.29 mm compared with those obtained with ultrasound biometry (23.89±0.28 mm, p=0.003). The mean refractive cornea power values of the horizontal meridian measured using a keratometer (42.50±0.47 D) and an IOL Master (42.69±0.49 D) were not statistically different (p=0.187). The mean values of the refractive cornea power of the vertical meridian obtained using a keratometer (42.62±0.48D) and an IOL Master (43.36±0.51 D) exhibited a statistically significant difference (p=0.000). The keratometer obtained statistically significant lower mean values of corneal refractive power (42.73±0.32 D) compared with those obtained with optical biometry (43.22±0.35 D, p=0.000). Ultrasound biometry obtained significantly increased the mean values of IOL power (20.19±0.48D) compared with those obtained with optical biometry (19.71±0.48 D, p=0.018). The large number of patients who receive an operation for dense cataracts indicate the need for representation of both biometric methods in our clinical practice.

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Biometric parameters and intra ocular lens power used for cataract eyes in Karnali, Nepal

Nepalese Journal of Ophthalmology ◽

10.3126/nepjoph.v6i2.11690 ◽

2014 ◽

Vol 6 (2) ◽

pp. 192-196

Author(s):

Pawan Baral ◽

Nabin Baral ◽

Indra Man Maharjan ◽

Bhoj Raj Gautam ◽

Madhavendra Bhandari

Keyword(s):

Cataract Surgery ◽

Axial Length ◽

Total Sample ◽

Ocular Lens ◽

Biometric Parameters ◽

Number Of Patients ◽

Case Files ◽

Iol Power ◽

The Mean ◽

Lens Power

Introduction: The biometric parameters of the eye are measured for the calculation of the intra ocular lens power to be used in cataract surgery. Objective: To report the keratometry reading, axial length and intra ocular lens power used for eyes operated for cataract in Karnali Zone, Nepal, and to compare these findings with those reported in other similar studies. Subjects and methods: The data for the study were retrospectively collected from the case files of patients who had undergone cataract surgery between January 2011 and July 2012 in Karnali Zone, Nepal. These surgeries were performed in an outreach surgical camp organized by the Himalaya Eye Hospital, Nepal, as a part of its annual program. The SPSS 16.0 and Microsoft Excel 2007 software were used for the data analysis.Results: The total number of patients taken for the study was 1055 and the total number of eyes was 1055. There were 530 (50.23%) males and 525 (49.77%) females, with the mean age of 64.34±11.25, ranging from 8 to 98 years.The mean keratometry reading for the total sample was 44.11±1.6 (range, 34.00D to 49.00D). The mean axial length for the total sample was 22.68±0.88 (range, 17.75 to 26.17). The mean IOL power for the total sample was 21.60±1.74 (range, +15.00 to +30.00).Conclusion: The biometric eye parameters of keratometry, axial length and IOL power of this study required for cataract surgery in a Karnali population are similar to those presented in other similar studies from Nepal and abroad.DOI: http://dx.doi.org/10.3126/nepjoph.v6i2.11690Nepal J Ophthalmol 2014; 6(12): 192-196

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The Accuracy of Different Generation Intraocular Lens Power Formulas in Eyes with Axial Length Lower than 22 millimeter

10.21203/rs.2.19177/v1 ◽

2019 ◽

Author(s):

Aydın Yildiz ◽

Sedat Arikan

Keyword(s):

Intraocular Lens ◽

Axial Length ◽

Statistical Significance ◽

Absolute Error ◽

Accurate Estimation ◽

Intraocular Lens Power ◽

Significant Difference ◽

Iol Calculation ◽

Iol Power ◽

Lens Power

Abstract Background:To investigate the accurate formulas for eyes with axial length (AL) lower than 22 millimeters among usually used six intraocular lens (IOL) calculation formulas. MethodsA total of 122 eyes with short ALs that is lower than 22 mm of 122 patients who underwent phacoemulsification surgery with the same type of IOL implantation were included in this retrospective study. The biometric values of the patients were obtained by using optical low coherence reflectometry (OLCR) for six formulas involving Hoffer Q, SRK-T, Haigis, Barett Universal II, Holladay 2 and Hill-RBF. All patients had a postoperative best corrected visual acuity level that is equal or higher than 20/40. While comparing the accuracy of these six IOL calculation formulas, the mean absolute error (MAE), and the median absolute error (MedAE) values were taken into account.ResultsThe MAE values for Hoffer Q, SRK-T, Haigis, Holladay 2, Hill-RBF and Barrett Universal II formulas were 0.390, 0.390, 0.324, 0.327, 0.331 and 0.208 respectively. Also the rank of MedAE values for the mentioned formulas was 0.245, 0.310, 0.310, 0.250, 0.255 and 0.190. The lowest MAE and MedAE value was found in Barrett Universal II formula, whereas the highest one was in the SRK/T formula with a statistical significance (p<0.001). After Bonferroni correction, there were no statistically significant difference between Barret Universal II formula and the other formulas except SRK/T (p>0.01). Three patients (2.5%) were in the ±0.75 D range, 15 patients (12.3%) were in the ±0.50 D, and the remaining 104 (85.2%) patients were in the ±0.25 D at the first month follow-up. ConclusionsAlthough Barrett Universal II appears to be the most accurate IOL calculation formula, third, fourth and other newer generation formulas have also a good predictive value for accurate estimation of IOL power in short eyes.

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

Pakistan Journal of Ophthalmology ◽

10.36351/pjo.v34i2.947 ◽

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.

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Congenital and developmental cataract surgery with undercorrected Intraocular lens (IOL) power implantation targeting emmetropia at 8 years of age and post-operative refractive status

Asian Journal of Medical Sciences ◽

10.3126/ajms.v12i9.36890 ◽

2021 ◽

Vol 12 (9) ◽

pp. 126-129

Author(s):

Kabindra Bajracharya ◽

Anjita Hirachan ◽

Kriti Joshi ◽

Bimala Bajracharya

Keyword(s):

Cataract Surgery ◽

Intraocular Lens ◽

Axial Length ◽

Iol Implantation ◽

Refractive Status ◽

Developmental Cataract ◽

Iol Power ◽

The Mean ◽

One Year

Background: In congenital and developmental cataract primary undercorrection of intraocular lens (IOL) power is a common practice. However, long-term refractive status of these children is largely unknown. Aims and Objective: To analyse refractive status after cataract surgery with undercorrected IOL power implantation in congenital and developmental cataract. Materials and Methods: This study was descriptive, retrospective conducted for three years from 1st January 2013 to 31st December 2015. The children (> 6 months to <=7 years of age) who underwent cataract surgery for congenital and developmental cataract with a primary IOL implantation and had reached the age of 8 years were studied. The data were collected in terms of demography, axial length, biometry, IOL implanted, hyperopic correction and postoperative refractive status at 8 years. Results: Total numbers of children operated were 181 with total eyes 288. Unilateral cases were 74 (40.88%) and bilateral 107 (59.12%). Male were 121 (66.85%) and female were 60 (33.15%) with male is to female ratio of 2:1. Right eye was involved in 152 (52.8%) and left eye 136 (47.2%). The mean axial length at the age of one year was 20.75 mm, and gradually increased as age increased which was 22.47 mm at 6 years. The mean biometry was 27.9 diopter (D) at the age of one year which gradually decreased as age increased. Of the total 288 congenital cataract operated, complete follow-up documents were available for 77 (26.74%) eyes up to 8 years which showed emmetropia achieved in 25.97%, myopia in 28.57% and hypermetropia in 45.45%. Conclusion: Primary IOL implantation with hyperopic correction is accepted practice in congenital and developmental cataract. Emmetropia can be achieved however some hyperopic or myopic refractive status at the age of 8 years is not a surprise. Myopic shift continues as the age increases. Parent awareness for early detection and surgery, optical correction and regular follow-up are essential for good outcome.

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

European Journal of Ophthalmology ◽

10.1177/1120672121994720 ◽

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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Correction for near vision in pseudophakic patients

Srpski arhiv za celokupno lekarstvo ◽

10.2298/sarh0410291d ◽

2004 ◽

Vol 132 (9-10) ◽

pp. 291-293

Author(s):

Mirjana Dujic ◽

Katarina Misailovic ◽

Milena Kovacevic ◽

Dragana Babic

Keyword(s):

Anterior Chamber ◽

Anterior Chamber Depth ◽

Good Position ◽

Inclusion Criteria ◽

New Materials ◽

Near Vision ◽

Mean Values ◽

Refractive Power ◽

Significant Difference ◽

The Mean

Objective of the study was to show the mean values of correction for near vision and to discuss the presbyopic correction in pseudophakic patients. Setting was the Eye department where authors work. Inclusion criteria for 55 patients were native or corrected distant vision of 0.8-1.0 on Snellen's chart; 0,6 on Jagger's chart for near vision; round pupil and good position of the implant. Biometry of the anterior chamber depth with Alcon biophysics during distant and near vision was performed in our study. ?Hi square" test was carried out and it was concluded that patients younger than 59 years (41 eyes) had median correction of +2.0 dsph, while patients older than 60 years (36 eyes) had correction of+3.0 dsph, but it was not statistically significant. There was no statistically significant difference of the correction between pseudophakic (41) and phakic (19) eyes in patients younger than 59 years. The anterior movement of the IOL was 0.18 mm in the younger group and 0.15 mm in the older group. With good IOL movement and new materials which could have changeable refractive power, the problem of pseudophakic correction for near vision might be solved.

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Changes in Axial Length After Vitrectomy for Rhegmatogenous Retinal Detachment With Associated Choroidal Detachment

10.21203/rs.3.rs-58749/v1 ◽

2020 ◽

Author(s):

Jipeng LI ◽

Jun XU ◽

Meng ZHAO

Keyword(s):

Retinal Detachment ◽

Axial Length ◽

Rhegmatogenous Retinal Detachment ◽

Silicone Oil ◽

Choroidal Detachment ◽

Pathological Myopia ◽

Number Of Patients ◽

Significant Difference ◽

Potential Factors ◽

Lens Power

Abstract BACKGROUND The precise pre-operative measurements of axial length (AL) are essential for calculating intraocular lens power in cases undertaking pars plana vitrectomy (PPV) combined with cataract surgery. The changes in AL after PPV for rhegmatogenous retinal detachment (RRD) combined with choroidal detachment (CD) has not been reported. Here, we studied the postoperative AL changes in patients with RRD combined with CD (RRD-CD) and compared the changes in patients with RRD and tractional retinal detachment (TRD). METHODS In this retrospective cohort study, medical records of 129 patients who received PPV combined with silicone oil tamponade from January 2015 to December 2018 were reviewed. Patients included were divided into three groups, RRD-CD, RRD, and TRD. All patients had received AL measurements before PPV and before silicone oil removal (SOR). The changes in AL of three groups before PPV and before SOR were compared. The potential factors related to AL changes were analyzed. RESULTS The number of patients included in RRD-CD, RRD, TRD groups were 41, 43, and 45, respectively. In RRD-CD group, AL measured before SOR was longer than that measured before PPV with a median of 1.01 [0.37,1.79] mm (p = 0.02). There was no such significant difference in RRD group (0.15 [0.04, 0.42] mm, p = 0.58) or TRD group (0.07[-0.03,0.15] mm, p = 0.53). The amplitude of AL changes in RRD-CD group was greater than that in RRD group (p < 0.001) and that in TRD group (p < 0.001). AL increased 0.06 mm (0.06, R2 = 0.11, p = 0.03) in RRD-CD group and 0.02 mm (0.02, R2 = 0.11, p = 0.01) in RRD group when the IOP before SOR was 1 mmHg higher than that before PPV. After adjusting the effect of the factors as the presence of pathological myopia (p = 0.45), IOP before PPV (p = 0.86), sustained elevation of IOP in post-PPV follow up (p = 0.51), AL in RRD-CD group was 11.42 times (3.54, 46.80) more likely to increase for more than 1 mm compared to that in RRD group (p < 0.001, AIC = 86.15). CONCLUSION Patients with RRD-CD are very likely to have postoperative elongation of AL. The primary IOL implantation using pre-operative AL data may cause significant refractive error in combined surgery in patients with RRD-CD.

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A comparison of axial length measurement by using applanation A- Scan and IOL master for accuracy of predicting postoperative refraction

Indian Journal of Clinical and Experimental Ophthalmology ◽

10.18231/j.ijceo.2021.095 ◽

2021 ◽

Vol 7 (3) ◽

pp. 477-481

Author(s):

Harish R Trivedi ◽

Bhavik C Zala ◽

Nitesh S Pancholi

Keyword(s):

Cataract Surgery ◽

Intraocular Lens ◽

Axial Length ◽

Length Measurement ◽

Power Calculation ◽

Spherical Equivalent ◽

Significant Difference ◽

Group A ◽

Iol Power ◽

Group B

The higher cost of IOL master is an issue in developing countries and hence it cannot be widely used for calculation of IOL power in such countries. Thus, the aim of the current study is to evaluate a cheaper alternative for the calculation of IOL power by comparing the axial length measurement obtained using applanation A-scan with that of IOL Master for accuracy of predicting postoperative refraction.A prospective, randomized, comparative study was done with 100 patients who were posted for cataract surgery. The patients were randomly divided into two groups of 50 patients each using computerized random number method. In Group A (n=50) axial length was measured with applanation A-scan and in Group B (n=50) axial length was measured with IOL Master. Before cataract surgery keratometry reading was taken with auto keratometer and intraocular lens (IOL) power calculation was done using SRK 2 formula in all patients. All patients were operated for cataract surgery by phacoemulsification and foldable intraocular lens were implanted in the bag. Postoperatively, best accepted refraction at 8th week was taken and mean spherical equivalent was calculated. 100 patients of cataract were subjected for cataract surgery by phacoemulsification.Corrected spherical equivalent on 8th postoperative week showed: 88% patients in Group A and 96% patients of Group B were within ± 1.00 D.56% patients of Group A and 76% patients of Group B were within ± 0.50 D.There was no statistically significant difference (p > 0.05) in axial length and corrected spherical equivalent between the two groups. There is no extra advantage of IOL Master over applanation A-scan for measuring Axial Length between 21 and 24.50 and predicting post-operative refractive outcome.

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Comparative Analysis of Refractive Result Predictability During Iridocapsular and Iridovitreal Fixation of Biplanar Intraocular Lens

Ophthalmology in Russia ◽

10.18008/1816-5095-2018-2-139-145 ◽

2018 ◽

Vol 15 (2) ◽

pp. 139-145

Author(s):

B. E. Malyugin ◽

E. N. Panteleev ◽

A. N. Bessarabov ◽

D. F. Pokrovskiy ◽

A. S. Semakina ◽

...

Keyword(s):

Comparative Analysis ◽

Intraocular Lens ◽

Mean Value ◽

Fixation Method ◽

Spherical Equivalent ◽

Mean Values ◽

Refractive Outcomes ◽

Significant Difference ◽

Iol Power ◽

Phacoemulsification Cataract Surgery

Purpose: to carry out a comparative analysis of refractive outcomes and features during preoperational calculation of the biplanar intraocular lens (IOL) with iridocapsular and iridovitreal fixation.Patients and methods. Study included the analysis IOL model RSP-3 implantation after phacoemulsification cataract surgery with subluxated lens grade 2. Analyzed 309 eyes of 304 patients with iridocapsular (n = 44) (ICF) and iridovitreal fixation (n = 265) (IVF). In both groups IOL power was calculated with use of A- constant (118.2) recommended by manufacturer. Mean period of examination was 6 months. To count optimized A-constant in both groups we used next data: IOL power and axial length before surgery, keratometry, spherical equivalent and IOL effective position during 6 months after surgery.Results. In group with ICF postoperative refraction was achieved ± 0,5 D in 10 cases (23%), in group IVF — in 29 cases (11%). Mean value of optimized A-constant for IOL model RSP-3 in groups with ICF and IVF were 117.2 ± 1.18 (114.0–120.8) and 116.9 ± 1,89 (109.6 до 123.6). There were no statistically significant difference between compared groups (p = 0.46).Conclusion. Use of A-constant recommended by manufacturer do not allow achieving target refraction in most cases. Mean values of biplanar IOL A-constant counted for ICF and IVF were 117,2 and 116,9 respectively, what should be taken into account during IOL power count, according to its fixation method.

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Comparison of four formulas for the intraocular lens power prediction

10.21203/rs.2.9117/v1 ◽

2019 ◽

Author(s):

Yanjun Hua ◽

Wei Qiu ◽

Qiang Wu

Keyword(s):

Prospective Study ◽

Intraocular Lens ◽

Axial Length ◽

Power Prediction ◽

Ocular Biometry ◽

Intraocular Lens Power ◽

Iol Power ◽

Lens Power ◽

Better Than

Abstract Purpose To assess the accuracy of four formulas for intraocular lens (IOL) power prediction in cataractous eyes. METHODS In this prospective study, 51 eyes of 38 cataractous patients with an axial length (AL) between 24.0 and 26.0 mm were included. Preoperatively, Topolyzer, IOLMaster and A-scan were performed. At least 3 months after the surgery, subjective refraction was conducted. Haigis, SRK/T, Hoffer Q and Holladay 1 formulas based on ocular biometry from A-scan combining Topolyzer, IOLMaster combining Topolyzer and IOLMaster only were applied for IOL power prediction. RESULTS The four formulas based on biometry from IOLMaster combining Topolyzer and IOLMaster only performed better than those based on biometry from A-scan combining Topolyzer. Based on biometry from IOLMaster combining Topolyzer, Haigis formula had a mean NEs of -0.03 ± 0.71 D and a mean AEs of 0.53 ± 0.47 D, SRK/T formula had a mean NEs of 0.37 ± 0.72 D and a mean AEs of 0.63 ± 0.50 D, Hoffer Q formula had a mean NEs of 0.05 ± 0.62 D and a mean AEs of 0.43 ± 0.44 D, Holladay 1 formula had a mean NEs of 0.32 ± 0.63 D and a mean AEs of 0.54 ± 0.45 D. Based on biometry from IOLMaster only, Haigis formula had a mean NEs of 0.02 ± 0.54 D and a mean AEs of 0.41 ± 0.36 D, SRK/T formula had a mean NEs of 0.41 ± 0.54 D and a mean AEs of 0.52 ± 0.43 D, Hoffer Q formula had a mean NEs of 0.05 ± 0.58 D and a mean AEs of 0.36 ± 0.46 D, Holladay 1 formula had a mean NEs of 0.32 ± 0.45 D and a mean AEs of 0.43 ± 0.35 D. CONCLUSIONS Haigis and Hoffer Q formulas performed slightly better than SRK/T and Holladay 1 formulas. Therefore, for cataractous patients with moderate AL, all four formulas based the biometry from IOLMaster combining Topolyzer and IOLMaster only can be used for the prediction of IOL power, and the Haigis and Hoffer Q formulas are particularly recommended.

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