Keratometry, biometry, and prediction of intraocular lens power in adult tigers (Panthera tigris)

2021 ◽  
pp. 1-7
Author(s):  
Cameron D. Owens ◽  
Tammy M. Michau ◽  
Justin Boorstein ◽  
Elizabeth R. Wynn ◽  
Richard J. McMullen
Keyword(s):  
Anterior Chamber ◽  
Intraocular Lens ◽  
Anterior Chamber Depth ◽  
Crystalline Lens ◽  
Applanation Tonometry ◽  
Normal Adult ◽  
Panthera Tigris ◽  
Clinically Normal ◽  
Iol Power ◽  
Lens Power

Abstract OBJECTIVE To calculate the necessary pseudophakic intraocular lens (IOL) power to approximate emmetropia in adult tigers. ANIMALS 17 clinically normal adult tigers. PROCEDURES 33 eyes of 17 clinically normal adult tigers underwent routine ophthalmic examination and B-scan ultrasonography while anesthetized for unrelated procedures. Specific ultrasound data (globe measurements and corneal curvature) and estimated postoperative IOL positions were utilized to calculate predicted IOL power by use of Retzlaff and Binkhorst theoretical formulas. Applanation tonometry and refraction were also performed. RESULTS Mean ± SD axial globe length was 29.36 ± 0.82 mm, preoperative anterior chamber depth was 7.00 ± 0.74 mm, and crystalline lens thickness was 8.72 ± 0.56 mm. Mean net refractive error (n = 33 eyes) was +0.27 ± 0.30 diopters (D). By use of the Retzlaff formula, mean predicted IOL power for the postoperative anterior chamber depth (PACD), PACD – 2 mm, and PACD + 2 mm was 43.72 ± 4.84 D, 37.62 ± 4.19 D, and 51.57 ± 5.72 D, respectively. By use of the Binkhorst equation, these values were 45.11 ± 4.91 D, 38.84 ± 4.25 D, and 53.18 ± 5.81 D, respectively. Mean intraocular pressure for all eyes was 14.7 ± 2.69 mm Hg. CLINICAL RELEVANCE The calculated tiger IOL was lower than reported values for adult domestic felids. Further studies evaluating actual PACD and pseudophakic refraction would help determine the appropriate IOL power to achieve emmetropia in this species.

scholarly journals Comparison of axial length, anterior chamber depth and intraocular lens power between IOLMaster and ultrasound in normal, long and short eyes

PLoS ONE ◽  
2018 ◽  
Vol 13 (3) ◽  
pp. e0194273 ◽  
Author(s):  
Jing Dong ◽  
Yaqin Zhang ◽  
Haining Zhang ◽  
Zhijie Jia ◽  
Suhua Zhang ◽  
...  
Keyword(s):  
Anterior Chamber ◽  
Intraocular Lens ◽  
Axial Length ◽  
Anterior Chamber Depth ◽  
Intraocular Lens Power ◽  
Lens Power

Quantitative biometric cutoffs for the choice of the intraocular lens power calculation formula for a recently introduced nondiffractive extended depth-of-focus intraocular lens

2021 ◽  
pp. 112067212110655
Author(s):  
Alessandro Arrigo ◽  
Gianpiera Gambaro ◽  
Francesco Fasce ◽  
Emanuela Aragona ◽  
Innocente Figini ◽  
...  
Keyword(s):  
Anterior Chamber ◽  
Intraocular Lens ◽  
Axial Length ◽  
Anterior Chamber Depth ◽  
Power Calculation ◽  
Calculation Formula ◽  
Intraocular Lens Power Calculation ◽  
Intraocular Lens Power ◽  
Lens Power ◽  
Lens Power Calculation

Purpose This study aimed to analyze biometry values cutoffs for the choice of the best intraocular lens power calculation formula for AcrySof IQ Vivity intraocular lens. Methods The study was designed as interventional case series with 3 months of follow-up. Intraocular lens power calculation formulas included Barrett Universal II and SRK/T. The first was adopted for the intraocular lens power choice. The quantitative analysis focused on the identification of specific biometric cutoffs considering axial length, anterior chamber depth, and corneal powers. We included only the dominant eye in the statistical analysis. Results One hundred and eight eyes of 54 patients (23 males; mean age 62 ± 5 years) with no ocular diseases were included. Best-corrected visual acuity improved from 0.3 ± 0.2 to 0.0 ± 0.0 logMAR. All the eyes reached spectacles-free far and intermediate visions; a spherical addition of + 1.0D was necessary to adjust near vision. We identified significant quantitative cutoffs based on axial length and anterior chamber depth. Barrett Universal II resulted the best formula for eyes disclosing an axial length >25 mm, whereas SRK/T turned out to be the best choice for the eyes characterized by an anterior chamber depth <2.8 mm. Our analysis disclosed an overall sensitivity of 0.8 and a specificity of 0.7 ( p < 0.01). Conclusions Axial length and anterior chamber depth influence the choice of Barrett Universal II and SRK/T formulas. Quantitative biometric cutoffs may be useful to discriminate the best formula to be adopted.

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.

Sign in / Sign up

Export Citation Format

Share Document