Comparison of biometric methods in young children with congenital cataracts in their eyes

BACKGROUND: Relevant keratometric and biometric indicators are necessary for intraocular lens (IOL) power calculation, which is difficult to verify in young children. AIM: Evaluation of the accuracy of various ultrasound methods and optical biometry for axial length measurement in young children with congenital cataracts. MATERIAL AND METHODS: Forty-six children (74 eyes) with congenital cataracts (43 eyes) and pseudophakia (31 eyes) at the age of 6 months to 4 years were examined. Various methods measured the axial length: ultrasound A-scan under general anesthesia by US-4000, ultrasound B-scan without general anesthesia by Voluson E8, and optical biometry by AL-Scan in cases of transparent optics. RESULTS: The greater axial length difference was observed between A-scan and optical biometry (less by 0,78 mm) than between B-scan and optical biometry (more by 0,27 mm). The median axial length difference between A-scan and B-scan was equal for infants and young children with congenital cataracts (0,525 mm and 0,535 mm, respectively). CONCLUSION: Axial length should be measured by different methods in young children with their further comparison to obtaining more accurate biometric indicators for IOL power calculation. The decrease of 12 mm in axial length, which occurs during the A-scan, can lead to errors in the IOL calculation of 36 diopters and unplanned refraction in the long-term period.

Download Full-text

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.

Download Full-text

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

British Journal of Ophthalmology ◽

10.1136/bjophthalmol-2020-315882 ◽

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.

Download Full-text

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

Clinical Ophthalmology ◽

10.2147/opth.s256851 ◽

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

Download Full-text

Assessment of the Influence of Keratometry on Intraocular Lens Calculation Formulas in Long Axial Length Eyes

10.21203/rs.3.rs-639671/v1 ◽

2021 ◽

Author(s):

Shengjie Yin ◽

Chengyao Guo ◽

Kunliang Qiu ◽

Tsz Kin Ng ◽

Yuancun Li ◽

...

Keyword(s):

Intraocular Lens ◽

Axial Length ◽

Case Series ◽

Absolute Error ◽

Power Calculation ◽

Prediction Errors ◽

Retrospective Case ◽

Iol Power Calculation ◽

Iol Power ◽

Intraocular Lens Calculation

Abstract Purpose: Hyperopic surprises tend to occur in axial myopic eyes and other factors including corneal curvature have rarely been analyzed in cataract surgery, especially in eyes with long axial length (≥ 26.0 mm). Thus, the purpose of our study was to evaluate the influence of keratometry on four different formulas (SRK/T, Barrett Universal II, Haigis and Olsen) in intraocular lens (IOL) power calculation for long eyes.Methods: Retrospective case-series. 180 eyes with axial length (AL) ≥ 26.0 mm were divided into 3 keratometry (K) groups: K ≤ 42.0 D (Flat), K ≥ 46.0 D (Steep), 42.0 < K < 46.0 D (Average). Prediction errors (PE) were compared between different formulas. Multiple regression analysis was performed to investigate factors associated with the PE.Results: The mean absolute error was higher for all evaluated formulas in Steep group (ranging from 0.66 D to 1.02 D) than the Flat (0.34 D to 0.67 D) and Average groups (0.40 D to 0.74D). The median absolute errors predicted by Olsen formula were significantly lower than that predicted by Haigis formula (0.42 D versus 0.85 D in Steep and 0.29 D versus 0.69 D in Average) in Steep and Average groups (P = 0.012, P < 0.001, respectively). And the Olsen formula demonstrated equal accuracy to the Barrett II formula in Flat and Average groups. The predictability of the SRK/T formula was affected by the AL and K, while the predictability of Olsen and Haigis formulas was affected by the AL only. Conclusions: Steep cornea has more influence on the accuracy of IOL power calculation than the other corneal shape in long eyes. Overall, both the Olsen and Barrett Universal II formulas are recommended in long eyes with unusual keratometry.

Download Full-text

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

Nepalese Journal of Ophthalmology ◽

10.3126/nepjoph.v6i1.10773 ◽

2014 ◽

Vol 6 (1) ◽

pp. 56-64 ◽

Cited By ~ 5

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

Download Full-text

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

Indian Journal of Pharmaceutical and Biological Research ◽

10.30750/ijpbr.6.3.1 ◽

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.

Download Full-text