DIFFERENCE BETWEEN TARGET AND POST OPERATIVE REFRACTIVE ERROR FOLLOWING CONGENITAL CATARACT SURGERY IN PAEDIATRIC PATIENTS VISITING ARMED FORCES INSTITUTE OF OPHTHALMOLOGY

Objective: To determine the difference between target and postoperative refraction in children with congenital cataract. Study design: Prospective interventional study Place and Duration of Study: This study was conducted at Armed Forces Institute of Ophthalmology from May 2017 to May 2018. Methods: This study was conducted on 38 eyes suffering from congenital cataract. Age at the time of surgery, axial length, average keratometry reading, estimated refraction, and the power of IOL implanted were recorded. Spherical equivalent of post-op refraction at 3 months after surgery was noted. The difference between the estimated and actual postoperative refraction was termed as prediction error. Age, keratometry, and axial length were then assessed for its effects on prediction error. Results: Overall the mean prediction error was 1.43±1.98 D. The mean prediction errors in eyes with axial lengths ⩾20 mm were 0.96± 1.03 D and in eyes <20 mm were 5.50± 3.49 D. The mean prediction errors in eyes in children aged ⩾4 years were 0.14± 0.61 D) and in children aged < 4 years was 2.60± 2.07 D. The differences between the prediction errors for both axial length and age were statistically significant (p<0.05). Conclusion: IOL power calculations in eyes with axial length less than 20 mm and children less than 4 years of age are prone to postoperative refractive errors. This study has reflected that adult based formulas are not reliable in pediatric age group.

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Accuracy Improvement of IOL Power Prediction for Highly Myopic Eyes With an XGBoost Machine Learning-Based Calculator

Frontiers in Medicine ◽

10.3389/fmed.2020.592663 ◽

2020 ◽

Vol 7 ◽

Author(s):

Ling Wei ◽

Yunxiao Song ◽

Wenwen He ◽

Xu Chen ◽

Bo Ma ◽

...

Keyword(s):

Machine Learning ◽

Axial Length ◽

Prediction Errors ◽

Power Prediction ◽

Accuracy Improvement ◽

Test Dataset ◽

Mean Squared Errors ◽

Iol Power ◽

The Mean ◽

External Test

Purpose: To develop a machine learning-based calculator to improve the accuracy of IOL power predictions for highly myopic eyes.Methods: Data of 1,450 highly myopic eyes from 1,450 patients who had cataract surgeries at our hospital were used as internal dataset (train and validate). Another 114 highly myopic eyes from other hospitals were used as external test dataset. A new calculator was developed using XGBoost regression model based on features including demographics, biometrics, IOL powers, A constants, and the predicted refractions by Barrett Universal II (BUII) formula. The accuracies were compared between our calculator and BUII formula, and axial length (AL) subgroup analysis (26.0–28.0, 28.0–30.0, or ≥30.0 mm) was further conducted.Results: The median absolute errors (MedAEs) and median squared errors (MedSEs) were lower with the XGBoost calculator (internal: 0.25 D and 0.06 D2; external: 0.29 D and 0.09 D2) vs. the BUII formula (all P ≤ 0.001). The mean absolute errors and were 0.33 ± 0.28 vs. 0.45 ± 0.31 (internal), and 0.35 ± 0.24 vs. 0.43 ± 0.29 D (external). The mean squared errors were 0.19 ± 0.32 vs. 0.30 ± 0.36 (internal), and 0.18 ± 0.21 vs. 0.27 ± 0.29 D2 (external). The percentages of eyes within ±0.25 D of the prediction errors were significantly greater with the XGBoost calculator (internal: 49.66 vs. 29.66%; external: 78.28 vs. 60.34%; both P < 0.05). The same trend was in MedAEs and MedSEs in all subgroups (internal) and in AL ≥30.0 mm subgroup (external) (all P < 0.001).Conclusions: The new XGBoost calculator showed promising accuracy for highly or extremely myopic eyes.

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Gender differences in refraction prediction error of five formulas for cataract surgery

BMC Ophthalmology ◽

10.1186/s12886-021-01950-2 ◽

2021 ◽

Vol 21 (1) ◽

Author(s):

Yibing Zhang ◽

Tingyang Li ◽

Aparna Reddy ◽

Nambi Nallasamy

Keyword(s):

Gender Differences ◽

Cataract Surgery ◽

Prediction Error ◽

Statistical Difference ◽

Independent Predictor ◽

Study Data ◽

Prediction Errors ◽

Optical Biometry ◽

Iol Power ◽

Lens Power

Abstract Objectives To evaluate gender differences in optical biometry measurements and lens power calculations. Methods Eight thousand four hundred thirty-one eyes of five thousand five hundred nineteen patients who underwent cataract surgery at University of Michigan’s Kellogg Eye Center were included in this retrospective study. Data including age, gender, optical biometry, postoperative refraction, implanted intraocular lens (IOL) power, and IOL formula refraction predictions were gathered and/or calculated utilizing the Sight Outcomes Research Collaborative (SOURCE) database and analyzed. Results There was a statistical difference between every optical biometry measure between genders. Despite lens constant optimization, mean signed prediction errors (SPEs) of modern IOL formulas differed significantly between genders, with predictions skewed more hyperopic for males and myopic for females for all 5 of the modern IOL formulas tested. Optimization of lens constants by gender significantly decreased prediction error for 2 of the 5 modern IOL formulas tested. Conclusions Gender was found to be an independent predictor of refraction prediction error for all 5 formulas studied. Optimization of lens constants by gender can decrease refraction prediction error for certain modern IOL formulas.

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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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Effects of Orthokeratology Lens On Axial Length Elongation in Myopia With Anisometropia Children

10.21203/rs.3.rs-741927/v1 ◽

2021 ◽

Author(s):

Ziyang Chen ◽

Kai-Ming Chen ◽

Ying Shi ◽

Zhao-Da Ye ◽

Sheng Chen ◽

...

Keyword(s):

Retrospective Study ◽

Axial Length ◽

Statistical Significance ◽

Spherical Equivalent ◽

Significant Difference ◽

The Mean ◽

The Difference ◽

Better Than ◽

Group 1

Abstract AimTo investigate the effect of orthokeratology (OK) lens on axial length (AL) elongation in myopia with anisometropia children.MethodsThirty-seven unilateral myopia (group 1) and fifty-nine bilateral myopia with anisometropia children were involved in this 1-year retrospective study. And bilateral myopia with anisometropia children were divided into group 2A (diopter of the lower SER eye under − 2.00D) and group 2B(diopter of the lower SER eye is equal or greater than − 2.00D). The change in AL were observed.The datas were analysed using SPSS 21.0.Results(1) In group 1, the mean baseline AL of the H eyes and L eye were 24.70 ± 0.89 mm and 23.55 ± 0.69 mm, respectively. In group 2A, the mean baseline AL of the H eyes and L eyes were 24.61 ± 0.84 mm and 24.00 ± 0.70 mm respectively. In group 2B, the mean baseline AL of the H eyes and L eyes were 25.28 ± 0.72 mm and 24.70 ± 0.74 mm. After 1 year, the change in AL of the L eyes was faster than the H eyes in group 1 and group 2A (all P<0.001).While the AL of the H eyes and L eyes had the same increased rate in group 2B. (2) The effect of controlling AL elongation of H eyes is consistent in three groups (P = 0.559).The effect of controlling AL elongation of L eyes in group 2B was better than that in group 1 and group 2A (P < 0.001). And the difference between group 1 and group 2A has no statistical significance. (3) The AL difference in H eyes and L eyes decreased from baseline 1.16 ± 0.55mm to 0.88 ± 0.68mm after 1 year in group 1.And in group 2A, the AL difference in H eyes and L eyes decreased from baseline 0.61 ± 0.34mm to 0.48 ± 0.28mm. There was statistically significant difference (all P<0.001). In group 2B, the baseline AL difference in H eyes and L eyes has no significant difference from that after 1 year (P = 0.069).ConclusionsMonocular OK lens is effective on suppression AL growth of the myopic eyes and reduce anisometropia value in unilateral myopic children. Binocular OK lenses only reduce anisometropia with the diopter of the low eye under − 2.00D. Binocular OK lenses cannot reduce anisometropia with the diopter of the low eye equal or greater than − 2.00D. Whether OK lens can reduce refractive anisometropia value is related to the spherical equivalent refractive of low refractive eye in bilateral myopia with anisometropia children after 1-year follow-up.

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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.

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An innovative approach for determining the customized refractive index of ectatic corneas in cataractous patients

Scientific Reports ◽

10.1038/s41598-020-73492-4 ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

Shiva Pirhadi ◽

Keivan Maghooli ◽

Khosrow Jadidi

Keyword(s):

Refractive Index ◽

Cataract Surgery ◽

Ray Tracing ◽

Prediction Error ◽

Power Calculation ◽

Corneal Power ◽

Iol Power Calculation ◽

Iol Power ◽

Hyperopic Shift ◽

The Difference

Abstract The aim of this study is to determine the customized refractive index of ectatic corneas and also propose a method for determining the corneal and IOL power in these eyes. Seven eyes with moderate and severe corneal ectatic disorders, which had been under cataract surgery, were included. At least three months after cataract surgery, axial length, cornea, IOL thickness and the distance between IOL from cornea, and aberrometry were measured. All the measured points of the posterior and anterior parts of the cornea converted to points cloud and surface by using the MATLAB and Solidworks software. The implanted IOLs were designed by Zemax software. The ray tracing analysis was performed on the customized eye models, and the corneal refractive index was determined by minimizing the difference between the measured aberrations from the device and resulted aberrations from the simulation. Then, by the use of preoperative corneal images, corneal power was calculated by considering the anterior and posterior parts of the cornea and refractive index of 1.376 and the customized corneal refractive index in different regions and finally it was entered into the IOL power calculation formulas. The corneal power in the 4 mm region and the Barrett formula resulted the prediction error of six eyes within ± 1 diopter. It seems that using the total corneal power along with the Barrett formula can prevent postoperative hyperopic shift, especially in eyes with advanced ectatic disorders.

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Amphetamine disrupts haemodynamic correlates of prediction errors in nucleus accumbens and orbitofrontal cortex

10.1101/802488 ◽

2019 ◽

Cited By ~ 1

Author(s):

Emilie Werlen ◽

Soon-Lim Shin ◽

Francois Gastambide ◽

Jennifer Francois ◽

Mark D Tricklebank ◽

...

Keyword(s):

Nucleus Accumbens ◽

Orbitofrontal Cortex ◽

Prediction Error ◽

Learning Task ◽

Adaptive Behaviour ◽

Diagnostic Feature ◽

Prediction Errors ◽

Guided Learning ◽

The Difference ◽

Precise Relationship

AbstractIn an uncertain world, the ability to predict and update the relationships between environmental cues and outcomes is a fundamental element of adaptive behaviour. This type of learning is typically thought to depend on prediction error, the difference between expected and experienced events, and in the reward domain this has been closely linked to mesolimbic dopamine. There is also increasing behavioural and neuroimaging evidence that disruption to this process may be a cross-diagnostic feature of several neuropsychiatric and neurological disorders in which dopamine is dysregulated. However, the precise relationship between haemodynamic measures, dopamine and reward-guided learning remains unclear. To help address this issue, we used a translational technique, oxygen amperometry, to record haemodynamic signals in the nucleus accumbens (NAc) and orbitofrontal cortex (OFC) while freely-moving rats performed a probabilistic Pavlovian learning task. Using a model-based analysis approach to account for individual variations in learning, we found that the oxygen signal in the NAc correlated with a reward prediction error, whereas in the OFC it correlated with an unsigned prediction error or salience signal. Furthermore, an acute dose of amphetamine, creating a hyperdopaminergic state, disrupted rats’ ability to discriminate between cues associated with either a high or a low probability of reward and concomitantly corrupted prediction error signalling. These results demonstrate parallel but distinct prediction error signals in NAc and OFC during learning, both of which are affected by psychostimulant administration. Furthermore, they establish the viability of tracking and manipulating haemodynamic signatures of reward-guided learning observed in human fMRI studies using a proxy signal for BOLD in a freely behaving rodent.

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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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Dopamine, Prediction Error and Beyond

The Neuroscientist ◽

10.1177/1073858420907591 ◽

2020 ◽

pp. 107385842090759

Author(s):

Kelly M. J. Diederen ◽

Paul C. Fletcher

Keyword(s):

Prediction Error ◽

Large Body ◽

Theoretical Models ◽

Optimal Choice ◽

Reward Processing ◽

Prediction Errors ◽

The Difference ◽

Past Experiences ◽

Mental Pathology

A large body of work has linked dopaminergic signaling to learning and reward processing. It stresses the role of dopamine in reward prediction error signaling, a key neural signal that allows us to learn from past experiences, and that facilitates optimal choice behavior. Latterly, it has become clear that dopamine does not merely code prediction error size but also signals the difference between the expected value of rewards, and the value of rewards actually received, which is obtained through the integration of reward attributes such as the type, amount, probability and delay. More recent work has posited a role of dopamine in learning beyond rewards. These theories suggest that dopamine codes absolute or unsigned prediction errors, playing a key role in how the brain models associative regularities within its environment, while incorporating critical information about the reliability of those regularities. Work is emerging supporting this perspective and, it has inspired theoretical models of how certain forms of mental pathology may emerge in relation to dopamine function. Such pathology is frequently related to disturbed inferences leading to altered internal models of the environment. Thus, it is critical to understand the role of dopamine in error-related learning and inference.

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