scholarly journals The Effect of Pharmacological Dilation on Calculation of Targeted and Ideal IOL Power Using Multivariable Formulas

2019 ◽  
Author(s):  
Noah C Simon ◽  
Asim V. Farooq ◽  
Michael H. Zhang ◽  
Kamran M. Riaz
Keyword(s):  
Pupil Diameter ◽  
Corneal Thickness ◽  
Anterior Chamber Depth ◽  
Calculation Methods ◽  
Biometric Parameters ◽  
Higher Power ◽  
Before And After ◽  
Dioptric Power ◽  
Iol Power ◽  
Phakic Eyes

Abstract Background/Aims To examine the effect of pharmacologic dilation on biometric parameters measured by the Lenstar LS 900, and whether these changes affect the power of the calculated intraocular lens (IOL) using multivariable formulas in an undilated versus pharmacologically dilated state. Methods Prospective study of 98 phakic eyes from 53 patients. Axial length (AL), central corneal thickness (CCT), anterior chamber depth (ACD), lens thickness (LT), and keratometry (K) readings were measured. The first set of measurements was taken prior to dilation. After dilation (pupil diameter ≥6.0mm), a second set of measurements was taken. The Barrett, Olsen, Hill-RBF, Haigis, SRK/T, and Holladay I formulas were used to calculate IOL power before and after dilation. Two calculation methods were used: Method A used a commonly available IOL targeted to achieve the lowest myopic spheroequivalent residual refraction (LMP); Method B calculated ideal IOL power for emmetropia (IPE). Results Statistically significant increases were seen in CCT (p<0.01), ACD (p<0.01), and AL (p<0.01) whereas a statistically significant decrease was seen in LT (p<0.01) post dilation. Using Method A, the percentage of eyes which would have received an IOL with 0.5 D or 1.0 D of higher power, if post-dilation measurements were used, were 25.5%, 30.6%, 20.4% and 23.5% for Barrett, Olsen, Hill-RBF and Haigis, respectively. Using Method B, only Haigis and Olsen had a statistically significant increase in ideal IOL power. Conclusions Pharmacologic dilation can be associated with an increase in non-custom IOL dioptric power when using multivariable formulas, which may lead to a myopic surprise.

scholarly journals Biometric changes after vitrectomy with silicone oil tamponade

2021 ◽  
Vol 2 (2) ◽  
pp. 56-62
Author(s):  
Simin Hosseini ◽  
Amir Faramarzi ◽  
Siamak Moradian ◽  
Mehdi Yaseri
Keyword(s):  
Silicone Oil ◽  
Corneal Thickness ◽  
Anterior Chamber Depth ◽  
Biometric Data ◽  
Cavity Depth ◽  
Time Points ◽  
Biometric Parameters ◽  
Before And After ◽  
Silicone Oil Tamponade

Background: The Lenstar LS 900 (Haag-Streit AG, Koeniz, Switzerland) is an optical biometer, and its measurements are highly repeatable and precise in cataractous eyes. This study investigated changes in biometric parameters, including axial length (AL), anterior chamber depth (ACD), lens thickness (LT), vitreous cavity depth (VD), and central corneal thickness (CCT) before and after three-port 23-Gauge pars plana vitrectomy with silicone oil tamponade. Methods: This was a prospective follow-up study. Patients who were scheduled for surgery underwent a detailed slit-lamp examination and objective cycloplegic refraction preoperatively. In eligible cases, the Lenstar LS 900 was used to measure biometric parameters. At the 1-month postoperative follow-up, we repeated the same assessments for the silicone oil (SO)-filled eyes. Data were analyzed to assess the significance of changes and to test the possible correlation of values between the two time points. Results: Twenty-three patients with a mean ± SD age of 60 ± 12 years completed the study. Postoperatively, we found a significant increase in AL and a decrease in ACD and CCT (all P < 0.05), with no significant changes in LT and VD. A significant correlation was found for ACD, CCT, and cylinder values between the two time points (all P < 0.05). Postoperatively, the spherical and cylindrical components of refraction demonstrated a hyperopic shift, but did not change statistically significantly. Conclusions: The Lenstar LS 900 underestimated the ACD and overestimated the AL in SO-filled eyes when comparing pre- and postoperative values, in phakic as well as pseudophakic eyes. In planning for cataract surgery in this group of patients, it is more reasonable to calculate IOL power based on the biometric data of the fellow eye, although this may not eliminate possible errors. Further studies with a larger sample size, longer follow-up, and robust study design are necessary to confirm our preliminary results.

scholarly journals Unintended changes in ocular biometric parameters during a 6-month follow-up period after FS-LASIK and SMILE

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Junjie Wang ◽  
Bernardo T. Lopes ◽  
Hechen Li ◽  
Riccardo Vinciguerra ◽  
Si Cao ◽  
...  
Keyword(s):  
Anterior Chamber ◽  
Corneal Endothelium ◽  
Corneal Thickness ◽  
Anterior Chamber Depth ◽  
Laser In Situ Keratomileusis ◽  
Biometric Parameters ◽  
Refractive Outcomes ◽  
Post Surgery ◽  
Before And After

AbstractBackgroundCorneal refractive surgery has become reliable for correcting refractive errors, but it can induce unintended ocular changes that alter refractive outcomes. This study is to evaluate the unintended changes in ocular biometric parameters over a 6-month follow-up period after femtosecond laser-assisted laser in situ keratomileusis (FS-LASIK) and small incision lenticule extraction (SMILE).Methods156 consecutive myopic patients scheduled for FS-LASIK and SMILE were included in this study. Central corneal thickness (CCT), mean curvature of the corneal posterior surface (Kpm), internal anterior chamber depth (IACD) and the length from corneal endothelium to retina (ER) were evaluated before and after surgery over a 6-month period.ResultsBoth the FS-LASIK and SMILE groups (closely matched at the pre-surgery stage) experienced flatter Kpm, shallower IACD and decreased ER 1 week post-surgery (P < 0.01), and these changes were larger in FS-LASIK than in SMILE group. During the 1 week to 6 months follow up period, Kpm, IACD and ER remained stable unlike CCT which increased significantly (P < 0.05), more in the FS-LASIK group.ConclusionsDuring the follow up, the posterior corneal surface became flatter and shifted posteriorly, the anterior chamber depth and the length from the corneal endothelium to retina decreased significantly compared with the pre-surgery stage. These unintended changes in ocular biometric parameters were greater in patients undergoing FS-LASIK than SMILE. The changes present clear challenges for IOL power calculations and should be considered to avoid affecting the outcome of cataract surgery.

scholarly journals Effect of Cycloplegia on Keratometric and Biometric Parameters in Keratoconus

2016 ◽  
Vol 2016 ◽  
pp. 1-6
Author(s):  
Nihat Polat ◽  
Abuzer Gunduz
Keyword(s):  
Axial Length ◽  
Healthy Subjects ◽  
Anterior Chamber Depth ◽  
Corneal Curvature ◽  
Corneal Surface ◽  
Biometric Parameters ◽  
Before And After ◽  
The Difference ◽  
Group 2 ◽  
Group 1

Purpose.To obtain information about effect of cycloplegia on keratometry and biometry in keratoconus.Methods.48 keratoconus (Group 1) and 52 healthy subjects (Group 2) were included in the study. We measured the flat meridian of the anterior corneal surface (K1), steep meridian of the anterior corneal surface (K2), lens thickness (LT), anterior chamber depth (ACD), and axial length (AL) using the Lenstar LS 900 before and after cycloplegia.Results.The median K1 in Group 1 was 45.64 D before and 45.42 D after cycloplegia, and the difference was statistically significant (P<0.05). The median K2 in Group 1 was 50.96 D before and 50.17 D after cycloplegia, and the difference was significant (P<0.05). The median K1 and K2 in Group 2 were 42.84 and 44.49 D, respectively, before cycloplegia, and 42.84 and 44.56 D after cycloplegia, and the differences were not statistically significant (allP>0.05). There were significant differences in SE, LT, ACD, and RLP between before and after cycloplegia in either Group 1 (allP<0.05) or Group 2 (allP<0.05). There were not statistically significant differences in AL between before cycloplegia and after cycloplegia in either Group 1 (P=0.533) or group 2 (P=0.529).Conclusions.Flattened corneal curvature and increase in ACD following cycloplegia in keratoconus patients were detected.

scholarly journals Comparison of tendency and accuracy in predicted post-operative refraction and recommended IOL power between IOL Master and VERION before and after optimizing IOL-constant in the VERION

2020 ◽  
Author(s):  
Takeshi Teshigawara ◽  
Akira Meguro ◽  
Nobuhisa Mizuki
Keyword(s):  
Mean Absolute Error ◽  
Anterior Chamber Depth ◽  
Absolute Error ◽  
Rank Test ◽  
K Value ◽  
Signed Rank ◽  
Before And After ◽  
Signed Rank Test ◽  
Iol Power ◽  
The Difference

Abstract Background: We assessed the accuracy and tendency of the VERION image-guided system (Alcon) and the intra-ocular lens (IOL) Master 700 (Zeiss), by comparing mean refractive shift (MRS) of predicted post-operative refraction (PPR), mean absolute error (MAE) of PPR, recommended IOL power (RIP) and K-value before and after optimizing the IOL-constant in VERION, to show the importance of optimization.Methods: This retrospective study involved 72 eyes. K-value was measured with both biometers. Axial length (AL) and anterior chamber depth (ACD) measured by the IOL Master were applied to the VERION because it cannot measure these variables. The User group for Laser Interference Biometry (ULIB) IOL-constant for the IOL Master was applied to the VERION before optimizing the IOL constant, since no such official measure was established for it. MRS of PPR, MAE of PPR, RIP and K-value as measured by both biometers were compared before and after optimizing the IOL-constant in the VERION. Finally, correlations between the MRS, MAE, RIP, and K-value were analyzed in the VERION. The Wilcoxon signed-rank test was used for analysis.Results: Compared to the IOL Master, K-value was significantly higher in the VERION. Prior to optimization, MRS of PPR showed a significant myopic shift in the VERION, and MAE of PPR was significantly higher. Additionally, RIP in the VERION was significantly lower. After optimization, there were no significant differences in the MRS of PPR and RIP between the VERION and IOL Master. MAE of PPR in the IOL Master was significantly higher than in the VERION. No significant correlations were found between MRS and MAE of PPR and RIP with K-value in the VERION. Conclusions: Before optimization, the VERION was less reliable in MRS, MAE and RIP than the IOL Master. However, after optimization, the difference in MRS and RIP between the two devices became insignificant. This study indicates that optimization of IOL-constant in the VERION is vital. After optimization, the VERION is more accurate in PPR than the IOL Master.

scholarly journals Comparison of intraocular lens power calculation results before and after glaucoma surgery

2020 ◽  
Vol 13 (4) ◽  
pp. 15-20
Author(s):  
Dmitrii Fedorovich Belov ◽  
Vadim Petrovich Nikolaenko
Keyword(s):  
Intraocular Lens ◽  
Anterior Chamber Depth ◽  
Glaucoma Surgery ◽  
Power Calculation ◽  
Ahmed Glaucoma Valve ◽  
Iol Power Calculation ◽  
Iol Calculation ◽  
Before And After ◽  
Iol Power ◽  
Target Refraction

Aim to compare intraocular lens (IOL) power calculation before and after different types glaucoma procedures. Material and methods.Into the study, 115 patients were included, divided into 3 groups: group 1 patients, in whom sinustrabeculectomy was performed (n= 86); group 2 patients with implanted Ex-PRESS shunt (n= 19), group 3 patients after Ahmed glaucoma valve implantation (n= 10). For each patient before surgery optical biometry (IOL-Master 500) was performed and IOL power calculation using Barrett Universal II Formula (target refraction emmetropia). Baseline data were compared with corresponding examinations results obtained in 6 months after glaucoma procedure, to evaluate its effect on main biometric parameters of the eye and the IOL calculation accuracy. Results.Despite significant changes of optical and anatomic indices, mean values of target refraction before and after glaucoma surgery did not differ significantly: 0.00 0.03 versus 0.03 0.52 D (p= 0.628), 0.00 0.1 versus 0.19 0.61 D (p= 0.173), 0.04 0.08 versus 0.11 0.42 D (p= 0.269) for groups, respectively. However, there was a pronounced trend to the increase of target refraction data scattering. Conclusion.Glaucoma procedures cause changes of biometrical parameters of the eye, which leads to decrease in accuracy of IOL calculation. Consequently, when choosing intraocular lens, it is recommended to use measurement results obtained after glaucoma surgery. Keywords:intraocular lens; IOL power calculation; glaucoma; sinustrabeculectomy; Ex-PRESS shunt; Ahmed glaucoma valve; biometry; phacoemulsification; axial length; anterior chamber depth; keratometry.

Central Corneal Thickness, Anterior Chamber Depth, and Pupil Diameter Measurements Using Visante OCT, Orbscan, and Pentacam

2010 ◽  
Vol 26 (2) ◽  
pp. 127-133 ◽  
Author(s):  
Ahmet Taylan Yazici ◽  
Ercument Bozkurt ◽  
Cengiz Alagoz ◽  
Nese Alagoz ◽  
Gokhan Pekel ◽  
...  
Keyword(s):  
Anterior Chamber ◽  
Central Corneal Thickness ◽  
Pupil Diameter ◽  
Corneal Thickness ◽  
Anterior Chamber Depth

Evaluation of biometric parameters in phacomorphic glaucoma and mature cataracts

2020 ◽  
pp. 112067212091453
Author(s):  
Ali Keleş ◽  
Emine Şen ◽  
Ufuk Elgin
Keyword(s):  
Anterior Chamber ◽  
Axial Length ◽  
Odds Ratio ◽  
Central Corneal Thickness ◽  
Corneal Thickness ◽  
Anterior Chamber Depth ◽  
Mature Cataract ◽  
Biometric Parameters ◽  
Significant Difference ◽  
The Mean

Purpose: The aims of this study were to compare the biometric parameters and axial lengths of eyes with phacomorphic glaucoma and mature cataract and to identify differences that might predispose to development of phacomorphic glaucoma. Methods: Three hundred forty-two patients were enrolled in this retrospective study. The eyes were divided into four groups—Group (G)1: phacomorphic glaucoma ( n = 29), G2: mature cataract ( n = 313), G3: contralateral phacomorphic glaucoma ( n = 29), and G4: contralateral mature cataract ( n = 313). Central corneal thickness and anterior chamber depth were assessed by optical low-coherence reflectometry (Lenstar LS 900®; Haag-Streit AG, Switzerland), while axial length was determined by A-scan ultrasound biometry. Results: The mean central corneal thickness of G1 was significantly higher than in other groups ( p < 0.001) and the mean anterior chamber depth of G1 was the lowest among the groups ( p < 0.001). Also, G2 had lower mean anterior chamber depth than G4 ( p < 0.001) and G3 had lower mean anterior chamber depth than G4 ( p = 0.007). Anterior chamber depth less than 3.27 mm had the higher odds ratio for distinguishing G3 versus G4 (odds ratio = 10.79, p < 0.001). Furthermore, patients aged ⩾68.9 years had the higher odds ratio for distinguishing G1 versus G2 (odds ratio = 2.82, p = 0.019). There was no significant difference in the presence of pseudoexfoliation material between G1 and G2 ( p = 0.057). There were no significant differences in axial length values among the four groups ( p = 0.097). Conclusion: Advanced age and shallow anterior chamber depth were found to be risk factors for developing phacomorphic glaucoma, but the presence of pseudoexfoliation material was not found to play a role as a risk factor in phacomorphic glaucoma development.

scholarly journals Comparison of the influence of pupil dilation on predicted postoperative refraction and recommended intraocular lens power among Barrett Universal II, Haigis, and SRK/T calculation formulas: a retrospective study

2019 ◽  
Author(s):  
Takeshi Teshigawara ◽  
Akira Meguro ◽  
Nobuhisa Mizuki
Keyword(s):  
Retrospective Study ◽  
Intraocular Lens ◽  
Significant Positive Correlation ◽  
Anterior Chamber Depth ◽  
Pupil Dilation ◽  
Power Calculation ◽  
Positive Correlation ◽  
Iol Calculation ◽  
Before And After ◽  
Iol Power

Abstract Background We investigated the effect of pupil dilation on predicted postoperative refraction (PPR) and recommended intraocular lens (IOL) power calculated using three different generations of IOL power calculation formulas: Barrett Universal II (Barrett) (new generation), Haigis (4th generation), and SRK/T (3rd generation).Methods This retrospective study included 150 eyes. The following variables were measured and calculated using an optical biometer before and after dilation: anterior chamber depth (ACD), lens thickness (LT), white-to-white (WTW), mean absolute change (MAC) in PPR, and recommended IOL power. PPR and recommended IOL power were calculated by Barrett, Haigis, and SRK/T IOL calculation formulas. Correlations between all changes were analyzed. The influence of pupil dilation on recommended IOL power calculated by each formula was also analyzed.Results MAC in PPR before and after dilation was highest in Barrett, followed by Haigis and SRK/T. Significant differences were found among each MAC. Significant changes were observed before and after dilation in ACD and LT but not in WTW. In Barrett and Haigis, there was a significant positive correlation between change in PPR and change in ACD and a negative correlation between change in PPR and change in LT. Correlations were strongest in Barret followed by Haigis, especially in LT. Change in PPR in Barrett also demonstrated a significant positive correlation with change in WTW. The recommended IOL power using Barrett and Haigis changed before and after dilation in 23.3% and 19.3% cases; SRK/T showed no change.Conclusions In PPR and recommended IOL power, pupil dilation influenced Barrett most strongly, followed by Haigis and SRK/T. Given the stronger correlation between the change in PPR in Barrett and the change in ACD, LT, and WTW, the change of ACD, LT, and WTW is more important to the influence of dilation on Barrett. The influence of dilation on each formula and variables, including ACD, LT, and WTW is key to improving IOL calculation.

scholarly journals IOP change after phacoemulsification with PCIOL implantation and its association with ocular biometric parameters

2021 ◽  
Vol 7 (3) ◽  
pp. 466-470
Author(s):  
Sharah Rahman ◽  
Jalal Ahmed ◽  
Anisur Rahman ◽  
Ishtiaque Anwar ◽  
Tarzia Asma Zafrullah ◽  
...  
Keyword(s):  
Graphical Representation ◽  
Linear Regression Analysis ◽  
Corneal Thickness ◽  
Anterior Chamber Depth ◽  
Posterior Chamber ◽  
Biometric Parameters ◽  
Age Related ◽  
Applanation Tonometer ◽  
The Mean ◽  
The Impact

: To assess the impact on intraocular pressure (IOP) after Phacoemulsification (PE) with Posterior Chamber Intraocular Lens (PCIOL) implantation and its relation with ocular biometric parameters. The study was a prospective observational study included 524 eyes with normal IOP (11-21 mmHg) who underwent uneventful Phacoemulsification with PCIOL Implantation surgery for age-related cataract. IOP, Central Corneal Thickness (CCT), Anterior Chamber Depth (ACD), Axial Length (AL) were measured pre-operatively and one month post-operatively by Goldman Applanation Tonometer, Corneal Pachymeter and Optical Coherence Biometer, respectively. The post-operative IOP change and its relation with preoperative biometric parameters were determined.: The mean pre-operative and post-operative IOP was 13.44±1.98 & 11.54±1.66mmHg, respectively, with an average IOP reduction after one month of 1.90±0.61mmHg. The mean pre-operative and post-operative ACD was 3.27±0.24 and 3.66±0.27 mm, respectively, with an average increase of 0.39 ±0.3 mm. Paired t-test showed post-operative IOP reduction was significantly associated with preoperative IOP (p&#60;0.001) and ACD (p&#60;0.001). But CCT and AL were not significantly associated. The linear regression analysis confirmed the proportional reduction of post-operative IOP, r 0.921. So 92.1% of the preoperative IOP is proportional to post-operative IOP reduction. The graphical representation shows more the pre-operative IOP, more the post-operative IOP reduction.: IOP is significantly reduced, and ACD increased after PE with PCIOL implantation surgery and is associated with post-operative IOP reduction. The post-operative IOP reduction is proportional to pre-operative IOP, and more the preoperative IOP, more the post-operative IOP reduction.

scholarly journals Evaluation of the Repeatability and the Reproducibility of AL-Scan Measurements Obtained by Residents

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Mehmet Kola ◽  
Hikmet Duran ◽  
Adem Turk ◽  
Suleyman Mollamehmetoglu ◽  
Ahmet Kalkisim ◽  
...  
Keyword(s):  
Corneal Thickness ◽  
Intraclass Correlation ◽  
Anterior Chamber Depth ◽  
Ocular Biometry ◽  
Iol Calculation ◽  
Iol Power ◽  
Good Repeatability ◽  
Repeatability And Reproducibility ◽  
Biometric Measurements ◽  
Power Measurements

Purpose. To assess the repeatability and reproducibility of ocular biometry and intraocular lens (IOL) power measurements obtained by ophthalmology residents using an AL-Scan device, a novel optical biometer.Methods. Two ophthalmology residents were instructed regarding the AL-Scan device. Both performed ocular biometry and IOL power measurements using AL-Scan, three times on each of 128 eyes, independently of one another. Corneal keratometry readings, horizontal iris width, central corneal thickness, anterior chamber depth, pupil size, and axial length values measured by both residents were recorded together with IOL power values calculated on the basis of four different IOL calculation formulas (SRK/T, Holladay, and HofferQ). Repeatability and reproducibility of the measurements obtained were analyzed using the intraclass correlation coefficient (ICC).Results. Repeatability (ICC, 0.872-0.999 for resident 1 versus 0.905-0.999 for resident 2) and reproducibility (ICC, 0.916-0.999) were high for all biometric measurements. Repeatability (ICC, 0.981-0.983 for resident 1 versus 0.995-0.996 for resident 2) and reproducibility were also high for all IOL power measurements (ICC, 0.996 for all).Conclusions. The AL-Scan device exhibits good repeatability and reproducibility in all biometric measurements and IOL power calculations, independent of the operator concerned.

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