Search

To ascertain the theoretical impact of optical design variations of the intraocular lens (IOL) on the accuracy of IOL power formulas based on a single lens constant using a thick lens eye model. This impact was also simulated before and after optimization. We modeled 70 thick-lens pseudophakic eyes implanted with IOLs of symmetrical optical design and power comprised between 0.50 D and 35 D in 0.5-step increments. Modifications of the shape factor resulting in variations in the anterior and posterior radii of an IOL were made, keeping the central thickness and paraxial powers static. Geometry data from three IOL models were also used. Corresponding postoperative spherical equivalent (SE) were computed for different IOL powers and assimilated to a prediction error of the formula due to the sole change in optical design alone. Formula accuracy was studied before and after zeroization on a uniform and non-uniform realistic IOL power distribution. The impact of the incremental change in optic design variability depended on the IOL power. Design modifications theoretically induce an increase in the standard deviation (SD), Mean Absolute Error (MAE), and Root Mean Square (RMS) of the error. The values of these parameters reduce dramatically after zeroization. While the variations in optical design can affect refractive outcomes, especially in short eyes, the zeroization of the mean error theoretically reduces the impact of the IOL’s design and power on the accuracy of IOL power calculation.

Biometric measurement of the anterior segment is of great importance for the ophthalmology, human eye modeling, contact lens fitting, intraocular lens design, etc. This paper serves as a comprehensive review on the historical development and basic principles of the technologies for measuring the geometric profiles of the anterior segment. Both the advantages and drawbacks of the current technologies are illustrated. For in vivo measurement of the anterior segment, there are two main challenges that need to be addressed to achieve high speed, fine resolution, and large range imaging. One is the motion artefacts caused by the inevitable and random human eye movement. The other is the serious multiple scattering effects in intraocular turbid media. The future research perspectives are also outlined in this paper.

We investigated whether eyes with keratoconic corneal tomography pattern could benefit more from aberration correction with custom intraocular lenses (IOLs) than normal cataractous eyes despite the effect of misalignment on the correction of aberrations. Custom IOLs (cIOLs) were calculated for twelve normal and twelve keratoconic eyes using personalized numerical ray tracing models. The Stiles-Crawford weighted root-mean-square spot-size (wRMS) at the virtual fovea was evaluated for cIOLs and aberration-neutral IOLs (nIOLs) in a simulated clinical study with 500 virtual IOL implantations per eye and per IOL. IOL misalignment (decentration, tilt, rotation) and pupillary ectopia (4.5 mm iris aperture) were varied upon each virtual implantation. The nIOLs achieved average wRMS of 16.4 ± 4.3 μm for normal, and 92.7 ± 34.4 μm for keratoconic eyes (mean ± standard deviation). The cIOLs reduced the average wRMS to 10.3 ± 5.8 μm for normal, and 28.5 ± 18.6 μm for keratoconic eyes. The cIOLs produced smaller wRMS than nIOLs in most virtual implantations (86.7% for normal and 99.4% for keratoconic eyes). IOL misalignment resulted in larger wRMS variations in the keratoconus group than in the normal group. Custom freeform IOL-optics-design may become a promising option for the correction of advanced aberrations in eyes with non-progressive keratoconic corneal tomography pattern.

PURPOSE: To compare visual outcomes, rotational stability, and centration in a randomized controlled trial in patients undergoing cataract surgery who were bilaterally implanted with two different trifocal intraocular lenses (IOLs) with a similar optical zone but different haptic shape. METHODS: Twenty-one patients (42 eyes) with cataract and less than 1.50 D of corneal astigmatism underwent implantation of one FineVision/MicoF IOL in one eye and one POD FineVision IOL in the contralateral eye (PhysIOL, Liège, Belgium) at IOA Madrid Innova Ocular, Madrid, Spain. IOL allocation was random. Outcome measures, all evaluated 3 months postoperatively, included monocular and binocular uncorrected distance (UDVA), corrected distance (CDVA), distance-corrected intermediate (DCIVA), and near (DCNVA) visual acuity (at 80, 40, and 25 cm) under photopic conditions, refraction, IOL centration, haptic rotation, dysphotopsia, objective quality of vision and aberration quantification, patient satisfaction, and spectacle independence. RESULTS: Three months postoperatively, mean monocular UDVA, CDVA, DCIVA, and DCNVA (40 cm) under photopic conditions were 0.04 ± 0.07, 0.01 ± 0.04, 0.15 ± 0.11, and 0.16 ± 0.08 logMAR for the eyes implanted with the POD FineVision IOL and 0.03 ± 0.05, 0.01 ± 0.02, 0.17 ± 0.12, and 0.14 ± 0.08 logMAR for those receiving the FineVision/MicroF IOL. Moreover, the POD FineVision IOL showed similar centration ( P > .05) and better rotational stability ( P < .05) than the FineVision/MicroF IOL. Regarding halos, there was a minimal but statistically significant difference, obtaining better results with FineVision/MicroF. Full spectacle independence was reported by all patients. CONCLUSIONS: This study revealed similar visual outcomes for both trifocal IOLs under test (POD FineVision and FineVision/MicroF). However, the POD FineVision IOL showed better rotational stability, as afforded by its design. [ J Refract Surg . 2016;32(6):394–402.]

Aim: To evaluate the outcomes after bilateral implantation of a new trifocal intraocular lens (IOL).Materials and Methods: The study included patients with visually significant cataract that underwent bilateral implantation of the Acriva Trinova Sinusoidal Trifocal IOL. The preoperative corrected distance visual acuity (CDVA) and postoperative uncorrected distance visual acuity (UDVA), CDVA, uncorrected intermediate (UIVA) and near visual acuities (UNVA) along with manifest refractions were assessed at 1 month and 6 months after cataract surgery. The defocus curve and contrast sensitivity (CS) were evaluated at the 6th month visit. Patient satisfaction and incidence of dysphotopic symptoms were assessed. Results: The study enrolled a total of 60 eyes of 30 patients, 10 males and 20 females aged 61.78± 8.73 years (range, 45 to 78 years). 90% of the patients (n: 27) achieved a binocular UIVA of 0.1 LogMAR or better at the 6-month visit while, 96.7% (n:29) patients had a binocular UNVA of 0.1 LogMAR or better in the same postoperative visit. The CS results were within the the range of normality at 6 months post-surgery. 6.7% of patients reported marked halo around light sources and 3.3% reported glare that interferes with nighttime driving. 96.6% of the patients reported spectacle independence for all distances and rated their visual function and quality satisfactory at all distances. Conclusion: Bilateral implantation of the Acriva Trinova Sinusoidal Trifocal IOL seems to provide effective restoration of visual function at all distances after cataract surgery in the majority of patients. Contrast sensitivity results and low incidence of dysphotopic phenomena might be associated with high patient satisfaction.

Purpose: To analyze biometry data and corneal astigmatism in cataract candidates from Yazd. Methods: The corneal thickness, anterior chamber depth and keratometry measurements of anteroposterior width were measured using the IOL Master system. Ocular biometric data were collected and analyzed in the year 2015. Results: The study comprised of 2000 patients' cataract candidates with a mean age of 66.79 ± 10.72 years (range 28 to 100 years). No significant differences were found between these variables for mean ± SDs of age and gender (p

12 págs.; 13 figs., Purpose To evaluate visual and perceptual performance for different orientations of a rotationally asymmetric bifocal intraocular lens (IOL) (M-Plus) simulated optically using a simultaneous vision simulator. Setting Instituto de Optica, Madrid, Spain. Design Prospective observational study. Methods Perceptual quality and decimal high-contrast visual acuity (HCVA) was measured under cycloplegia for 8 orientations of the asymmetric bifocal IOL phase pattern at far, intermediate, and near distances simulated with a simultaneous vision simulator using face images and tumbling E targets. The preferred orientation at each distance was calculated as the centroid of the data for 8 orientations. The visual Strehl value was calculated using the subjects' ocular aberrations and multifocal pattern at each orientation. Optical predictions were obtained by implementing a differential visual Strehl values–based ideal observer model. Results The study comprised 20 subjects (aged 21 to 62 years). Horizontal orientation (near segment at 0 or 180 degrees ± 45 [SD]) was preferred by 14 subjects and by 13 subjects at far and near distances, respectively; 8 subjects showed strong orientation preferences. The mean difference in preferred orientation between far and near was 27 ± 22 degrees. No significant differences in HCVA were observed. Optical predictions correlated strongly and significantly with measurements (far r = 0.71, near r = 0.62; P < .0001). The mean difference between measurement and simulation in the preferred orientation was 28 ± 29 degrees at far and 36 ± 28 degrees at near. Conclusions The perception varied for different orientations of an asymmetric bifocal IOL design tested using a simultaneous vision simulator. Optimum orientation was driven by interactions of the design with the eye's optical aberrations. Financial Disclosure None of the authors has a financial or proprietary interest in any material or method mentioned. Q 2016 ASCRS and ESCRS, Funding provided by the European Research Council under the European Union’s Seventh Framework Programme (FP7/2007- 2013)/ERC Grant Agreement number 294099 (Dr. Marcos), Spanish Government grant FIS2011-264605 and FIS2014-56643-R (Dr. Marcos), the 7th Framework Programme of the European Community through the Marie Curie Initial Training Network OpAL (OpAL is an Initial Training Network funded by the European Commission under the Seventh Framework Programme), (PITN-GA-2010- 264605, Dr. Radhakrishnan), and Oculentis GmBH, Germany.

Aim: To design an accommodating intraocular lens with extended accommodative range that can be adapted to current standard phacoemulsification and endocapsular implantation technique. Method: Ray tracing analysis and lens design; cadaver eye implantation. Results: Ray tracing analysis indicated that axial movement of an exaggerated converging anterior optic linked by spring loaded haptics to a compensatory static diverging posterior optic produced greater change in conjugation power of the eye compared to axial movement of a single optic lens. A dual optic one piece foldable silicone lens was constructed and implanted via a 4 mm corneal incision into the capsular bag of two cadaver eyes. Conclusion: A dual optic intraocular lens design can increase the optical effect of a given displacement and suggests improvements for accommodating intraocular lenses.

Of 1170 eyes implanted with posterior chamber lenses between 1981 and 1986 and having intact capsules at surgery, 1015 were examined two years after surgery, 741 were examined three years after surgery, and 308 were examined five years after surgery. At three years the capsulotomy rate for epithelium was 25% for 263 'lasergap' lenses, 2.4% for 296 convex posterior lenses, 8.2% for 73 planoposterior lenses with angulated loops. The highly significant difference for lasergap design, whether ridged, meniscus, or bossed, is of immediate interest to surgeons concerned with minimising the need for secondary capsulotomy. The two-year follow-up of soft hydrogel lenses suggested that these lenses also do not significantly retard the ingrowth of epithelium.

This manuscript reports on a closed-form solution determining the personalized required shape of a new intraocular lens able to remove spherical aberration and coma of a pseudophakic eye. The proposed analytical method, within the framework of the Seidel theory of third-order optical aberrations, considers corneal conicities, fourth-order aspheric surface of the intraocular optics, pupil-shift effect and ocular kappa angle.