Mesopic Disability Glare in Stage-Two Dysfunctional Lens Syndrome

Visual performance during night driving after intraocular refractive surgery procedures

INTRODUCTION

Cataracts reduce visual acuity and contrast sensitivity, and increase photic phenomena, especially at night. Recent advancements in cataract surgery have improved intraocular lens (IOL) designs. Monofocal, multifocal, and extended depth-of-focus IOLs offer different vision ranges but can still cause adverse visual effects like reduced contrast sensitivity and photic phenomena, affecting night driving. Investigating how different IOLs affect night driving is crucial for road safety and quality of life.

AREAS COVERED

Studies assessing night driving performance in patients who underwent surgery with monofocal, multifocal, and extended depth-of-focus IOL implantations were included in this review. The following databases were searched to conduct the review: PubMed, Scopus and Web of Science. The level of scientific evidence was graded according to the Scottish Intercollegiate Guidelines Network (SIGN).

EXPERT OPINION

Multifocal IOL implantation improves quality of life, however night driving continues to be challenging for some multifocal IOL patients whose neuroadaptation process has not been completed. Therefore, the use of validated questionnaires to adequately assess night driving before and after IOL implantation is highly recommended. Further well-designed randomized clinical trials are needed to objectively assess visual function during night driving. Night driving simulators could provide complementary reliable information to questionnaires' outcomes.

Visual Performance and Higher Order Aberrations Obtained With Omafilcon A Dual-Focus and Single-Vision Contact Lens Designs

OBJECTIVE

The purpose of this study was to assess the visual performance and monochromatic higher-order aberrations (HOAs) obtained while wearing a MiSight dual-focus (DF) contact lenses (CL) in comparison with a single-vision contact lens (SVCL).

METHODS

A randomized, double-masked, cross-over study was performed. Participants were fitted with a DFCL and a SVCL composed of the same material (omafilcon A) and parameters. Logarithm of the Minimum Angle of Resolution high-contrast (100%) and low-contrast (10%) visual acuity (VA) and contrast sensitivity (CS) for 3, 6, 12, and 18 cycles per degree were measured. Higher-order aberrations were also evaluated using a Hartmann-Shack aberrometer with the CLs on.

RESULTS

Twenty-four subjects (21 females and 3 males) with a mean age of 21.9±1.9 years (range: 18-27) were included. Low-contrast VA was significantly lower with the DFCL regarding the SVCL design (0.39±0.23 vs 0.25±0.18, P=0.002). However, there were no differences in high-contrast VA between both CLs (-0.03±0.10 vs -0.09±0.14, P=0.187). Contrast sensitivity was lower with the DFCL under all spatial frequencies (P≤0.048). Second-, third-, fourth-, and fifth-order aberrations were significantly (P<0.001) higher for the DFCL. There were also significant differences between DFCL and SVCL in defocus (0.87±0.28 vs 0.16±0.35, P<0.001), oblique trefoil (-0.16±0.27 vs -0.01±0.08, P=0.005), vertical coma (0.13±0.17 vs 0.00±0.08, P=0.002), and spherical aberration (0.09±0.11 vs -0.02±0.05, P=0.002).

CONCLUSION

Visual performance for detecting low-contrast targets is reduced when wearing MiSight DFCL compared with a SVCL with the same material. The main reason might be the induction of second-order and HOAs by the DFCL design.

Characterization of Dysfunctional Lens Index and Opacity Grade in a Healthy Population

This study enrolled 61 volunteers (102 eyes) classified into subjects < 50 years (group 1) and subjects ≥ 50 years (group 2). Dysfunctional Lens Index (DLI); opacity grade; pupil diameter; and corneal, internal, and ocular higher order aberrations (HOAs) were measured with the i-Trace system (Tracey Technologies). Mean DLI was 8.89 ± 2.00 and 6.71 ± 2.97 in groups 1 and 2, respectively, being significantly higher in group 1 in all and right eyes (both p < 0.001). DLI correlated significantly with age (Rho = −0.41, p < 0.001) and pupil diameter (Rho = 0.20, p = 0.043) for all eyes, and numerous internal and ocular root-mean square HOAs for right, left, and all eyes (Rho ≤ −0.25, p ≤ 0.001). Mean opacity grade was 1.21 ± 0.63 and 1.48 ± 1.15 in groups 1 and 2, respectively, with no significant differences between groups (p ≥ 0.29). Opacity grade significantly correlated with pupil diameter for right and all eyes (Rho ≤ 0.33, p ≤ 0.013), and with some ocular root-mean square HOAs for right and all eyes (Rho ≥ 0.23, p ≤ 0.020). DLI correlates with age and might be used complementary to other diagnostic measurements for assessing the dysfunctional lens syndrome. Both DLI and opacity grade maintain a relationship with pupil diameter and internal and ocular HOAs, supporting that the algorithms used by the device may be based, in part, on these parameters.