scholarly journals Analysis of the effect of intraocular lens tilt and decentration on induced astigmatism by ray tracing on the model eye

2021 ◽  
pp. 14-20
Author(s):  
I.L. Kulikova ◽  
◽  
N.S. Timofeyeva ◽  
D.B. Abramenko ◽  
◽  
...  
Keyword(s):  
Ray Tracing ◽  
Intraocular Lens ◽  
Horizontal Plane ◽  
Optical Power ◽  
Model Material ◽  
Intraocular Lenses ◽  
Eye Model ◽  
Intraocular Lens Tilt ◽  
Induced Astigmatism ◽  
Aspherical Iol

Purpose. Determination of the influence of the intraocular lens (IOL) inclination and decentration on the magnitude of induced astigmatism in a theoretical study using software on an eye model. Material and methods. An eye model with the specified parameters was performed to carry out the calculation. Modulation of the change in the wavefront was carried out using the Zemax program (LLC, USA). In the model eye, the probability of induction of astigmatism was analyzed depending on the change in the position of the aspherical IOL Acrysof IQ 16.0, 22.0 and 24.0 diopters and the toric model Acrysof IQ Toric SN6AT3, SN6AT4 and SN6AT5. The angle of inclination of the IOL relative to the horizontal plane was examined from 0° to 10° with a step of 1°, decentration from 0.1 to 1.5 mm with a step of 0.1 mm. At each IOL position, aberration data of the 2nd order Z (2, 2) were recorded. The obtained results were used to calculate the critical tilt angle and decentration. Results. The magnitude of induced astigmatism increased with the rise of the degree of inclination and decentration, corresponding to an increase in the optical power of the IOL. Accordingly, critically significant were the values of 3.0° inclination for the aspherical IOL with an optical power of 22.0 and 22.0 diopters and 3.5° for 16.0 diopters, decentration – 0.7 mm and 1.0 mm. The inclination of the TIOL relative to the horizontal plane revealed the induction of the magnitude of inverse astigmatism, according to an increase in the inclination angle of 0.3 diopters at a slope of 3–4°. Conclusions. The tilt and decentration of the aspherical and TIOL patterns induce astigmatism depending on the increase in IOL power. The inclination of the TIOL in relation to the horizontal plane set at 90 ° promotes the induction of astigmatism. Key words: astigmatism, toric intraocular lenses, tilt and decentration of the intraocular lens, ray tracing

Astigmatism induced by intraocular lens tilt evaluated via ray tracing

2018 ◽  
Vol 44 (6) ◽  
pp. 745-749 ◽  
Author(s):  
Mitchell P. Weikert ◽  
Abhinav Golla ◽  
Li Wang
Keyword(s):  
Ray Tracing ◽  
Intraocular Lens ◽  
Intraocular Lens Tilt

scholarly journals Optical bench simulation for intraocular lenses using field-tracing technology

PLoS ONE ◽  
2021 ◽  
Vol 16 (12) ◽  
pp. e0250543
Author(s):  
Seok Ho Song ◽  
In Seok Song ◽  
Se Jin Oh ◽  
Hyeck-Soo Son ◽  
Min Ho Kang
Keyword(s):  
Image Quality ◽  
Ray Tracing ◽  
Retinal Image ◽  
Spherical Aberration ◽  
Experimental Results ◽  
Intraocular Lenses ◽  
Optical Simulation ◽  
Optical Bench ◽  
Eye Model ◽  
Wave Nature

Purpose To evaluate the image quality of intraocular lenses (IOLs) using field-tracing optical simulation and then compare it with the image quality using conventional ray-tracing simulation. Methods We simulated aspheric IOLs with a decenter, tilt, and no misalignment using an aspheric corneal eye model with a positive spherical aberration. The retinal image, Strehl ratio, and modulation transfer function (MTF) were compared between the ray-tracing and field-tracing optical simulation and confirmed by the results reported in an in vitro experiment using the same eye model. Results The retinal image showed interference fringes from target due to diffraction from the object in a field-tracing simulation. When compared with the experimental results, the field tracing represented the experimental results more precisely than ray tracing after passing over 400 μm of the decentration and 4 degrees of the tilt of the IOLs. The MTF values showed similar results for the case of no IOL misalignment in both the field tracing and ray tracing. In the case of the 200-μm decentration or 8-degree tilt of IOL, the field-traced MTF shows lower values than the ray-traced one. Conclusions The field-tracing optical bench simulation is a reliable method to evaluate IOL performance according to the IOL misalignment. It can provide retinal image quality close to real by taking into account the wave nature of light, interference and diffraction to explain to patients having the IOL misalignment.

scholarly journals Intraocular lens tilt and decentration: A concern for contemporary IOL designs

1970 ◽  
Vol 3 (1) ◽  
pp. 68-77 ◽  
Author(s):  
Jit B Ale
Keyword(s):  
Image Quality ◽  
Intraocular Lens ◽  
Clinical Studies ◽  
Surgical Techniques ◽  
Intraocular Lenses ◽  
Posterior Chamber ◽  
Theoretical Studies ◽  
Posterior Chamber Intraocular Lens ◽  
Intraocular Lens Tilt

Purpose: To review published studies reporting the posterior chamber intraocular lens tilt and decentration after surgically uneventful implantation. Potential influences of normally occurring misalignment of modern designs of IOL on the optical performances are discussed. Materials and methods: Published theoretical and clinical studies in relation to primarily implanted posterior chamber intraocular lenses and reports relating to more recent development of intraocular lens technologies were reviewed. Results: Capsulotomy type and integrity, ocular pathology, fixation position of the haptics are some of the important factors causing the misalignment. On an average, a 2-3 degrees tilt and a 0.2 -0.3 mm decentration are common, and which remain clinically unnoticed for any design of IOL. However, theoretical studies predict deterioration of retinal image quality particularly with customized wavefront correcting IOLs. More than a 10 degrees tilt and above 1 mm decentration are occasionally reported even with modern cataract surgery in about 10 % of pseudophakic population. Conclusions: The rate and extent of the complication have lowered substantially concomitant with developments in surgical techniques and IOL designs. While emerging designs of modern IOLs offer improved quality of postoperative vision, optimum performance is vastly influenced by the position of the device in the eye. Therefore, additional precision in alignment of modern designs of IOL may be warranted. Key words: IOL misalignment; Intraocular Lens; modern IOL; consequences of misalignment DOI: 10.3126/nepjoph.v3i1.4281Nepal J Ophthalmol 2011;3(5):68-77

scholarly journals Optical bench simulation for intraocular lenses using field-tracing technology

2021 ◽  
Author(s):  
Seok Ho Song ◽  
In Seok Song ◽  
Se Jin Oh ◽  
Hyeck-Soo Son ◽  
Min Ho Kang
Keyword(s):  
Image Quality ◽  
Ray Tracing ◽  
Retinal Image ◽  
Spherical Aberration ◽  
Experimental Results ◽  
Intraocular Lenses ◽  
Optical Simulation ◽  
Optical Bench ◽  
Eye Model ◽  
Wave Nature

AbstractPurposeTo evaluate the image quality of intraocular lenses (IOLs) using field-tracing optical simulation and then compare it with the image quality using conventional ray-tracing simulation.MethodsWe simulated aspheric IOLs with a decenter, tilt, and no misalignment using an aspheric corneal eye model with a positive spherical aberration. The retinal image, Strehl ratio, and modulation transfer function (MTF) were compared between the ray-tracing and field-tracing optical simulation and confirmed by the results reported in an in vitro experiment using the same eye model.ResultsThe retinal image showed interference fringes from target due to diffraction from the object in a field-tracing simulation. When compared with the experimental results, the field tracing represented the experimental results more precisely than ray tracing after passing over 400 µm of the decentration and 4 degrees of the tilt of the IOLs. The MTF values showed similar results for the case of no IOL misalignment in both the field tracing and ray tracing. In the case of the 200-µm decentration or 8-degree tilt of IOL, the field-traced MTF shows lower values than the ray-traced one.ConclusionsThe field-tracing optical bench simulation is a reliable method to evaluate IOL performance according to the IOL misalignment. It can provide retinal image quality close to real by taking into account the wave nature of light, interference and diffraction to explain to patients having the IOL misalignment.

Towards the calculation of the optical power of an intraocular lens after thermokeratoplasty (a case report).

2018 ◽  
pp. 107-109
Author(s):  
O.I. Orenburkina ◽  
◽  
I.F. Nuriyev ◽  
A.E. Babushkin ◽  
N.A Nikitin ◽  
...  
Keyword(s):  
Case Report ◽  
Intraocular Lens ◽  
Optical Power

Evaluation of Intraocular Lens Tilt With Anterior Segment Optical Coherence Tomography

2011 ◽  
Vol 151 (3) ◽  
pp. 406-412.e2 ◽  
Author(s):  
Dhivya Ashok Kumar ◽  
Amar Agarwal ◽  
Gaurav Prakash ◽  
Soosan Jacob ◽  
Yoga Saravanan ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Intraocular Lens ◽  
Anterior Segment ◽  
Optical Coherence ◽  
Intraocular Lens Tilt

Vitreoretinal Surgery in the Treatment of Dislocations of Intraocular Lens and Nucleus-Lens Particules into the Vitreous Cavity

2021 ◽  
pp. 2-6
Keyword(s):  
Cataract Surgery ◽  
Intraocular Lens ◽  
Relative Frequency ◽  
Surgical Techniques ◽  
Vitreoretinal Surgery ◽  
Vitreous Cavity ◽  
Intraocular Lenses

Drops of lens nucleus/cortex particles into the vitreous cavity or dislocations of intraocular lenses (IOLs) are one of the serious complications of cataract surgery with an increasing relative frequency with the increase in the number of cataract surgeries. In addition, spontaneous and traumatic dislocations are other common case groups that should be treated. In this article, the vitreous dislocations of nucleus/cortex residues or IOL dislocations are discussed with different vitreoretinal surgical techniques.

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