Influence of trifocal intraocular lenses on standard automated refraction and aberrometer-based automated refraction

Purpose: To study the agreement between manifest refraction (Rx) and objective refraction (ObjRx) measured with two autorefractor models and an aberrometer, in eyes implanted with a trifocal diffractive intraocular lens. Setting: IOA Madrid Innova Ocular, Madrid, Spain. Design: Prospective comparative cohort study. Methods: A Topcon KR8800 autorefractor, based on a Scheiner double-pinhole, and a NIDEK OPD-SCAN III aberrometer, based on the scanning-slit retinoscopy principle, were used to obtain objective refraction (ObjRx) readings. In addition, lower-order Zernike coefficients (Z) were used to calculate ObjRx. A set of 7 different results in power vector notation [M(spherical equivalent), J0 and J45] for 7 different methods was obtained: Rx, AR (automated refraction obtained with the KR8800), WF-P (Z-based ObjRx for the photopic pupil), WF-M (Z-based ObjRx for the mesopic pupil), WF-4 (Z-based ObjRx for a 4 mm pupil), OPD-C (automated refraction measured with the OPD under photopic conditions), and OPD-M (automated refraction measured with the OPD under mesopic conditions). Results: The study comprised 102 eyes from 51 cataract patients who underwent binocular implantation of the POD F IOL. All 6 objective methods yielded more negative M values than manifest refraction (Rx) (p < 0.001). As for the astigmatism components (J0 and J45), only AR (p = 0.003) and OPD-M (p < 0.001) differed significantly from Rx. The best and worst correlation for the M component were ICC=0.70 (for WF-M) and ICC=0.48 (WF-4). Conclusions: Objective methods tend to yield more negative sphere values than manifest refraction

Interocular biometric parameters comparison measured with swept-source technology

Purpose: In the event that any ocular parameter involved in the calculation of intraocular lens power could not be properly measured in one eye, it is important to know whether clinically relevant differences between both eyes can be expected. The aim of this work is to evaluate the symmetry of interocular biometric parameters. Methods: This was a prospective, cross-sectional study involving 4090 subjects. Patients underwent consecutive swept-source optical biometry performed with an IOLMaster 700 (Carl Zeiss Meditec AG, Jena, Germany). The biometric parameters that were evaluated were: axial length (AL), mean anterior curvature (Rm), anterior chamber depth (ACD), crystalline lens thickness (LT), central corneal thickness (CCT) and white-to-white (WTW). The Chang-Waring chord distance (CWC-D) and the Chang-Waring chord angle (CWC-A) were also evaluated. Results: There is an excellent correlation between both eyes for almost all the biometric parameters under study, with the exception of the CWC. Agreement for AL was better for eyes shorter than 24 mm. The linearity of the OD-vs-OS relationship can be correctly assumed for all parameters (Cusum test: p > 0.05 in all cases). Conclusion: There are no clinically significant interocular differences for the biometric parameters under study, although for all of them, except the LT, statistically significant differences did arise. In the case of AL, moderate differences can be expected in eyes larger than 24 mm

Visual and optical quality of enhanced intermediate monofocal versus standard monofocal intraocular lens

Purpose: Intraocular lens designs are constantly evolving, trying to obtain more spectacle independence after cataract surgery. This advantage can be linked to some disadvantages, such as optical quality decrease. For that reason, it is important to assess, not only the amount of vision provided but also the quality of vision once they are implanted. The purpose of the present work was to compare the visual performance between two monofocal intraocular models: a standard model and a monofocal with enhanced intermediate vision lens. Methods: Prospective, randomized, comparative study. Sixty adult subjects scheduled to undergo bilateral cataract surgery and IOL implantation were randomized to receive one of the two IOLs in both eyes at Miranza IOA, Madrid, Spain (group A: monofocal with enhanced intermediate vision lens and group B: standard monofocal lens). Monocular outcomes (right eyes) determined 1 and 3 months postoperatively were photopic corrected distance visual acuity (CDVA), uncorrected distance visual acuity (UDVA), perceived halo, corrected intermediate-distance contrast sensitivity, and higher-order aberrations. The impact of the new IOL in the postoperative management with autorefraction devices was also evaluated. Results: No differences were found in CDVA between the two groups. Significant differences were detected between the two lenses evaluated in both total HOA (p = 0.028) and internal HOA (p = 0.037). Contrast sensitivity and halometry results obtained at 1 month were similar across the two IOL groups. Conclusion: In patients undergoing cataract surgery, monofocal with enhanced intermediate vision IOL offered similar distance performance and contrast sensitivity along with perceived HOA and halos compared with the standard monofocal IOLs tested

Influence of angle kappa on visual and refractive outcomes after implantation of a diffractive trifocal intraocular lens

Purpose: To evaluate changes in angle kappa following the implantation of a trifocal intraocular lens (IOL), and to assess the postoperative outcomes of patients with different angle kappa values. Setting: IOA Madrid Innova Ocular, Madrid, Spain Design: Prospective trial Methods: Sixty-three patients due to have bilateral implantation of the diffractive trifocal IOL (POD F, PhysIOL, Belgium) were included. Pupil offset was used as the best estimate of angle kappa and was measured using Pentacam (Oculus, Wetzlar, Germany) preoperatively and at 3-months after surgery. Postoperative refractive outcomes (sphere, cylinder, and MRSE) and visual outcomes at far, intermediate and near distance were assessed and compared between eyes with small pupil offset and eyes with large pupil offset. Quality of vision was assessed using a subjective questionnaire. Results: There was significant decrease in pupil offset post-operatively (mean: 0.197 ± 0.12 mm) compared to preoperatively (mean: 0.239 ± 0.12 mm), with a mean decrease of -0.042 mm (P = 0.0002). The same significant decrease was found for both the right eyes and left eyes, when analysed separately. No statistically significant difference was found in any of the refractive and visual acuity outcomes between eyes with small pupil offset and eyes with large pupil offset. The majority of patients (14 out of 16) complaining of significant halos had eyes with small pupil offset. Conclusion: Large pupil offset did not negatively affect visual and refractive outcomes. The tolerance to larger pupil offset might be due to the IOL optical design, with the first diffractive ring being larger than other commonly used multifocal IOLs. More studies comparing various diffractive IOL models will be useful to confirm such hypothesis