[Pupil centroid shift: Marketing tool or essential clinical parameter?]

Impact of Light Conditions on Visual Performance following Premium Pseudophakic Presbyopia Corrections

The primary objective of this study was to objectively compare the visual performance of patients following premium pseudophakic presbyopia corrections in different light combinations for near- and intermediate-vision activities of daily living (ADLs). This is a prospective, comparative study. A total of 75 patients populated three study groups: G1-patients with bilateral trifocal implantation, G2-patients with bilateral bifocal implantation, and G3-patients with bilateral monofocal implantation. All participants addressed 10 ADLs in nine combinations of light temperature (3000 K, 4000 K, and 6000 K) and light intensity (25 fc, 50 fc, and 75 fc) and declared their subjectively optimal light combination while reading. G2 and G3 had the best total ADL scores in 6000 K/75 fc, while G1 had the best total ADL score in 4000 K/75 fc. Total ADL, easy ADL, and moderate difficulty ADL scores were significantly better in G2, while difficult ADL score was significantly better in G1. The majority of all groups selected 6000 K/75 fc as the most comfortable light combination, and no group selected 3000 K and 25 fc. In conclusion, trifocal patients benefit from intense daylight, while bifocal and monofocal patients benefit from intense, cold lighting. Trifocal patients present superior near-vision capacity in difficult near-vision daily tasks, while bifocal patients present superiority in easy and moderate-difficulty ADLs.

The impact of visual axis position on the optical quality after implantation of multifocal intraocular lenses with different asphericity values

PURPOSE

To evaluate the effect of visual axis positioning on the optical performance of the Tecnis MIOL and the Diff-aA MIOL.

METHODS

In this prospective, randomized comparative study, 70 eyes of 35 subjects with senile cataract were implanted with the spherical aberration-correcting diffractive, bifocal Tecnis ZLB00 IOL and 60 eyes of 30 age-matched subjects with the spherical aberration neutral, diffractive, bifocal Diffractiva IOL. Observation procedure was performed 1, 3, and 6 months postoperatively. Main outcome measures included uncorrected and corrected distance and near visual acuity, manifest refraction, ocular aberrations, and visual quality metrics with 2 mm and 4 mm pupil and the position of visual axis.

RESULTS

At the 6-month visit, no significant difference was found in monocular and binocular uncorrected (UDVA) and corrected (CDVA) distance and near (UNVA, CNVA) visual acuity between the groups. Spherical and coma-like aberrations were similar measured with a 2-mm pupil, but with a 4-mm pupil, the SA was significantly larger (in negative direction) in the Diffractiva group. The higher-order Strehl ratio and MTF was significantly larger in the Diffractiva group measured at 2 mm entrance pupil; however, this difference disappeared by the 4-mm pupil measurements. Postoperative angle alpha distance had a significant influence on HO Strehl value.

CONCLUSIONS

The size of angle alpha is a predictive factor of image quality by multifocal IOL patients.

TRIAL REGISTRATION

Trial registration number and date of registration: NCT04274088, 14.02.2020.

Lower- and higher-order aberrations after photorefractive keratectomy with and without compensation of pupil centroid shift: fellow eye comparison

PURPOSE

To study the effect of pupil centroid shift (PCS) compensation on lower- and higher-order aberrations (HOAs) after photorefractive keratectomy (PRK).

SETTING

Labbafinejad Medical Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran.

DESIGN

Prospective intrasubject fellow eye study.

METHODS

One hundred twelve eyes of 56 patients with simple myopia or myopic astigmatism scheduled for PRK were enrolled. Preoperatively, the amount of PCS was measured in the horizontal and vertical directions. All eyes received wavefront-optimized treatment with static cyclotorsion compensation. PCS compensation was turned on for the right eye of each subject (PCS-on group), and turned off for the left eye (PCS-off group). Postoperatively, refraction and corneal HOAs were compared between the study groups at 6 months.

RESULTS

Mean preoperative myopia was -3.84 diopters (D) ± 2.41 (SD) vs -3.75 ± 2.27 D (P = .408), whereas mean preoperative cylinder was -1.18 D ± 1.15 (SD) vs -1.14 ± 1.16 D (P = .769) in the PCS-on and PCS-off groups, respectively. Mean absolute PCS values were 62.25 μm ± 41.82 (SD) vs 55.92 ± 37.47 μm (P = .45) in the horizontal direction and 65.04 ± 47.16 μm vs 58.40 ± 45.44 μm in the vertical direction (P = .29) in the PCS-on and PCS-off groups, respectively. The study groups were comparable in terms of postoperative refraction and root mean square of total corneal HOAs.

CONCLUSIONS

Compensation of PCS did not affect lower- and higher-order aberrations after wavefront-optimized PRK with static cyclotorsion compensation in myopic or myopic astigmatic eyes.

Impact of light conditions on reading ability following multifocal pseudophakic corrections

Purpose

To examine the impact of light intensity and temperature on reading performance following bilateral pseudophakic multifocal presbyopic correction.

Patients and methods

This is a prospective clinic-based trial conducted at the Department of Ophthalmology in the University Hospital of Alexandroupolis, Greece. Three groups of patients were formed (G1: patients with bilateral bifocal implantation, G2: patients with bilateral trifocal implantation, and control group: patients with bilateral pseudophakic monofocal implantation). Reading ability was quantified with the Greek version of MNREAD chart with minimal reading speed at 80 words/min for the following light intensities (25, 50, and 75 Foot-Candles [FC]) and temperatures (3,000, 4,000, and 6,000 K). Preferred light conditions for reading were assessed, as well. ClinicalTrials.gov Identifier: NCT03226561.

Results

Control group demonstrated significantly lower reading ability at all light combinations with maximal ability at 75 FC and 6,000 K (0.58±0.18 logMAR). Bifocal group presented a light-dependent reading ability that ranged from 0.45±0.08 logMAR (25 FC and 3,000 K) to 0.40±0.11 logMAR (75 FC and 4,000 or 6,000 K). Trifocal participants presented the best reading ability that was light intensity-independent; however, their performance was reduced at 6,000 K. G1 and G2 preferred primarily intermediate light temperature, while control participants preferred cold light temperature.

Conclusion

Multifocal pseudophakic corrections improve reading ability; however, they present variable efficacy according to the light conditions.

Predictive factors for photic phenomena after refractive, rotationally asymmetric, multifocal intraocular lens implantation

AIM

To investigate the independent factors associated with photic phenomena in patients implanted with refractive, rotationally asymmetric, multifocal intraocular lenses (MIOLs).

METHODS

Thirty-four eyes of 34 patients who underwent unilateral cataract surgery, followed by implantation of rotationally asymmetric MIOLs were included. Distance and near visual acuity outcomes, intraocular aberrations, preferred reading distances, preoperative and postoperative refractive errors, mesopic and photopic pupil diameters, and the mesopic and photopic kappa angles were assessed. Patients were also administered a satisfaction survey. Photic phenomena were graded by questionnaire. Independent-related factors were identified by correlation and bivariate logistic regression analyses.

RESULTS

The distance from the photopic to the mesopic pupil center (pupil center shift) was significantly associated with glare/halo symptoms [odds ratio (OR)=2.065, 95% confidence interval (CI)=0.916-4.679, P=0.006] and night vision problems (OR=1.832, 95% CI=0.721-2.158, P=0.007). The preoperative photopic angle kappa was significantly associated with glare/halo symptoms (OR=2.155, 95% CI=1.065-4.362, P=0.041). The photopic angle kappa was also significantly associated with glare/halo symptoms (OR=2.155, 95% CI=1.065-4.362, P=0.041) and with night vision problems (OR=1.832, 95% CI=0.721-2.158, P=0.007) in patients implanted with rotationally asymmetric MIOLs.

CONCLUSION

A large pupil center shift and misalignment between the visual and pupillary axis (angle kappa) may play a role in the occurrence of photic phenomena after implantation of rotationally asymmetric MIOLs.