Comparison of the Retinal Image Quality with a Hartmann-Shack Wavefront Sensor and a Double-Pass Instrument

Compact and aberration effects-shielded objective intraocular scatter measurement system

The measurement of the double-pass (DP) point spread function (PSF) provides an objective, non-invasive method for estimating intraocular scatter in the human eye. In this paper, we propose a compact double-pass objective intraocular scatter measurement system that eliminates the influence of aberrations. The system includes a far-field DP PSF detection channel and a Shack-Hartmann wavefront aberration detection channel, which are used to obtain the far-field DP PSF image and 7 orders Zernike aberration coefficients, respectively. The far-field DP PSF image is used to calculate the initial objective scatter index of the human eye. The aberration coefficients are used to reconstruct the DP PSF image caused by aberrations and calculate the influence coefficient of aberrations on intraocular scatter. By subtracting this influence coefficient from the initial objective scatter index (OSI0), the effect of aberrations on scatter measurement can be eliminated, resulting in an accurate objective scatter coefficient. Experimental verification showed that when the exit pupil aperture of this system was set to 4 mm and 6 mm, the measurement accuracy increased by at least 11.9% and 28.9%, respectively, compared to before eliminating the influence of aberrations. While improving the measurement accuracy, the system also keeps the device size and manufacturing costs at a low level, making it more suitable for clinical applications.

The impact of dry eye disease on retinal image quality in children

BACKGROUND AND OBJECTIVES

Dry eye disease (DED) is increasingly prevalent, resultinginhigher morbidityamong children. This study evaluates the impact of DED severity on visual quality using double-pass technology, focusing on dynamic observation of the ocular light scatter in pediatric DED cases.

METHOD

In this non-interventional, cross-sectional study, a mild DED group (37 cases, 37 eyes), a moderate DED group (40 cases, 40 eyes), and a control group of healthy children (35 cases, 35 eyes) were examined. Measurements included the Schirmer I test, tear film break-up time (BUT), and vision-related quality of life assessments using the Modified Ocular Surface Disease Index (OSDI) questionnaires. Participants underwent visual quality analysis using double-pass technology, which measured the modulation transfer function cut-off frequency value, Strehl ratio, objective scatter index (OSI), and OQAS-II value (OQAS-II value 100%, OQAS-II value 20%, and OQAS-II value 9%) under natural conditions. Additionally, dynamic changes in OSI post-blinking, Tear film mean-OSI , and the corresponding standard deviation OSI were recorded.

RESULTS

Statistically significant differences were observed among the groups in modulation transfer function cutoff, Strehl ratio, OSI, OQAS-II value 100 %, OQAs-II value 20 %, OQAs-II value 9 %, tear film mean OSI, and standard deviation OSI (P < 0.05). As DED severity increased, tear film mean OSI significantly rose, while modulation transfer function cutoff, strehl ratio, OQAS-II value 100 %, OQAS-II value 20 %, OQAS-II value 9 % notably declined. All optical quality parameters were correlated with BUT, with no association observed with age, sex, or Schirmer I test.

CONCLUSION

Dual-channel technology objectively assesses visual quality in pediatric DED, demonstrating that tear film scattering significantly affects retinal imaging and visual quality in children with DED.

Modulation transfer function formula for different age ranges

The modulation transfer function (MTF) is one of the most complete tools to study the optical performance of the eye. We present the average radial MTF profiles measured in 68 subjects grouped in six age ranges (from 20 to 80 years) and a general formula to estimate the radial profile of human MTF as a function of pupil size and age. The mean MTF for each age group was fitted to an analytical expression to compute two parameters related to aging. The proposed formula fitted reasonably well to experimental data available in previous works and predicted the average changes with aging of different optical quality parameters obtained from MTF.

Central and peripheral refraction measured by a novel double-pass instrument

A novel double-pass instrument and its data analysis method for the measurement of central and peripheral refraction is presented and validated in a group of healthy subjects. The instrument acquires in-vivo, non-cycloplegic, double-pass, through-focus images of the eye's central and peripheral point-spread function (PSF) using an infrared laser source, a tunable lens and a CMOS camera. The through-focus images were analyzed to determine defocus and astigmatism at 0° and 30° visual field. These values were compared to those obtained with a lab-based Hartmann-Shack wavefront sensor. The two instruments provided data showing good correlation at both eccentricities, particularly in the estimation of defocus.

Analysis of visual quality after multifocal intraocular lens implantation in post-LASIK cataract patients

With the development of refractive corneal surgery, excimer laser in situ keratomileusis (LASIK) has become a common refractive surgery procedure. However, post-LASIK patients are at increased risk of developing cataracts as they age and often require IOL implantation. The choice of IOLs is particularly important for these patients, who have smaller residual refractive error and have higher requirements for post-cataract vision recovery and visual quality than the general population. Multifocal IOLs are widely used in clinical practice for patients with high visual acuity needs, such as cataract patients after refractive keratomileusis, due to their advantages of providing excellent near and distance visual acuity; however, compared to monofocal IOLs, multifocal IOLs can lead to postoperative problems related to visual quality such as increased higher order aberrations and decreased contrast sensitivity. Therefore, whether multifocal IOLs have advantages for post-LASIK cataract patients, such as improving the visual quality of such patients, has attracted attention. In this paper, we analyze the current status of research on the implantation of multifocal IOLs in post-LASIK cataract patients by domestic and foreign experts, review and summarize the relevant literature, and propose further discussion in the context of the actual situation of postoperative visual quality and vision recovery.

Higher-order aberrations and visual quality after incision lenticule extraction surgery with intraoperative angle kappa adjustments between small and large kappa patients: A 2-year follow-up

Purpose

To evaluate the postoperative visual outcomes, that is, corneal higher-order aberrations (HOAs) and visual quality, of patients with an angle kappa greater than 0.30 mm who underwent angle kappa adjustment during small-incision lenticule extraction (SMILE) 2 years after surgery compared to eyes with an angle kappa less than 0.30 mm.

Methods

This was a retrospective study and included 12 patients from October 2019 to December 2019 who underwent the SMILE procedure for correction of myopia and myopic astigmatism and had one eye with a large kappa angle and another eye with a small kappa angle. Twenty-four months after surgery, an optical quality analysis system (OQAS II; Visiometrics, Terrassa, Spain) was used to measure the modulation transfer function cutoff frequency (MTF_cutoff), Strehl2D ratio, and objective scatter index (OSI). HOAs were measured with a Tracey iTrace Visual Function Analyzer (Tracey version 6.1.0; Tracey Technologies, Houston, TX, USA). Assessment of subjective visual quality was achieved using the quality of vision (QOV) questionnaire.

Results

At 24 months postoperatively, the mean spherical equivalent (SE) refraction was - 0.32 ± 0.40 and - 0.31 ± 0.35 in the S-kappa group (kappa <0.3 mm) and the L-kappa group (kappa ≥0.3 mm), respectively (P > 0.05). The mean OSI was 0.73 ± 0.32 and 0.81 ± 0.47, respectively (P > 0.05). There was no significant difference in MTF_cutoff and Strehl2D ratio between the two groups (P > 0.05). Total HOA, coma, spherical, trefoil, and secondary astigmatism were not significantly different (P > 0.05) between the two groups.

Conclusion

Adjustment of angle kappa during SMILE helps reduce the decentration, results in less HOAs, and promotes visual quality. It provides a reliable method to optimize the treatment concentration in SMILE.

Early Impact of Laser Vision Correction (LVC) on the Stability and Quality of the Retinal Image

This retrospective comparative study analyzes the early postoperative impact of laser vision correction for myopia on the optical quality and stability of functional vision using a double-pass aberrometer. Retinal image quality and visual function stability were assessed preoperatively, one and three months after myopic laser in situ keratomileuses (LASIK) and photorefractive keratectomy (PRK) using double-pass aberrometry (HD Analyzer, Visiometrics S.L, Terrassa, Spain). The parameters analyzed included vision break-up time (VBUT), objective scattering index (OSI), modulation transfer function (MTF), and Strehl ratio (SR). The study included 141 eyes of 141 patients, of whom 89 underwent PRK and 52 underwent LASIK. No statistically significant differences were noted between the two techniques in any analyzed parameters at three months postoperatively. However, a significant drop was observed in all parameters one month after PRK. Only the OSI and VBUT remained significantly altered from baseline at the three months follow-up visit, with an increased OSI by 0.14 +/- 0.36 (p < 0.01) and a shortened VBUT by 0.57 +/- 2.3 s (p < 0.01). No correlation was found between the changes in optical and visual quality parameters and age, ablation depth, or postoperative spherical equivalent. The stability and quality of the retinal images were similar between LASIK and PRK at three months postoperatively. However, significant degradation in all parameters was found one month after PRK.

Opto-Mechanical Eye Models, a Review on Human Vision Applications and Perspectives for Use in Industry

The purpose of this review is to aggregate technical information on existent optomechanical eye models (OME) described in the literature, for image quality assessment in different applications. Several physical eye models have been reviewed from peer-reviewed papers and patent applications. A typical eye model includes an artificial cornea, an intraocular lens or other lens to simulate the crystalline lens, an aperture as the pupil, and a posterior retinal surface, which may be connected to a light sensor. The interior of the eye model may be filled with a fluid to better emulate physiological conditions. The main focus of this review is the materials and physical characteristics used and the dimensional aspects of the main components including lenses, apertures, chambers, imaging sensors and filling medium. Various devices are described with their applications and technical details, which are systematically tabulated highlighting their main characteristics and applications. The models presented are detailed and discussed individually, and the features of different models are compared when applicable, highlighting strengths and limitations. In the end there is a brief discussion about the potential use of artificial eye models for industrial applications.

Benefits of Scleral Lens in the Management of Irregular Corneas and Dry Eye Syndrome After Refractive Surgery

OBJECTIVES

To evaluate the utility of the SPOT scleral lens (Oxygen Permeable Scleral Lens of Thonon; LAO, Thonon-les-Bains, France) in the management of the irregular cornea after refractive surgery.

METHOD

We included 19 patients (35 eyes) with irregular corneas after refractive surgery. Patients were fitted with scleral lenses after the failure of conventional contact lenses adaptation. The ophthalmologic examination included measurement of best-corrected visual acuity (BCVA), slitlamp examination, and evaluation of ocular aberrations (Objective Scattering Index [OSI] and higher-order aberration [HOA]).

RESULT

Scleral lens fitting increases significantly the BCVA from 0.33 (±0.25) to 0.08 (±0.13) LogMAR (P<0.001). There was also a significant decrease in Ocular Surface Disease Index from 66.2±22.8 to 42.4±18.9 (P<0.001). Ocular aberrations (OAs) are also significantly reduced by the scleral lenses, the mean OSI goes from 7.2 (±4.2) to 3.0 (±1.8) (P<0.001), OA from 2.58 (±1.34) to 1.98 μm (±2.31) (P=0.035), and HOA from 0.94 (±0.51) to 0.48 (±0.23) (P=0.0018).

CONCLUSION

Fitting with scleral lenses improves patients' optical and ocular surface problems. Scleral lens restores BCVA and the quality of life. Fitting with scleral lenses is an alternative to further surgery on these fragile eyes and is sometimes the only viable treatment option for the patient.

Short- and long-term effects of a multi-component, artificial tear on preocular tear film stability, tear evaporation and tear film optical dynamic: a prospective randomized double-phase study

AIM

To evaluate the short- (within 90 minutes) and long-term (after 21 days of treatment) effects of an artificial tear containing carbomer, hyaluronic acid, glycerol, and medium-chain triglycerides in patients with mild-to-moderate dry eye symptoms.

PATIENTS AND METHODS

Subjects received the tested artificial tears in the right eye and control artificial tears in the left eye and were assessed 10, 30, 60, and 90 minutes after instillation in the short-term study phase. They received the study product in both eyes in the long-term phase. Non-invasive break-up time (NIBUT), tear lipid layer pattern, tear evaporation, and tear film objective optical dynamics (TFOOD) were measured in controlled environmental conditions.

RESULTS

In total, 32 patients (10 males, mean age 42 ± 11 years) were enrolled. During the short-term phase, NIBUT increased significantly in the right eyes at all time points compared with baseline (all p < 0.05). Conversely, in the left eyes, NIBUT increased significantly at 10 and 30 min (p < 0.05). The tear evaporation values increased at 10 minutes and decreased at 30 and 60 minutes (p < 0.05) in the right eyes, while they increased only at 10 minutes (p < 0.05) in the left eyes. Compared with baseline, the TFOOD was significantly more stable at all time points in the right eyes (p < 0.05), while it was more stable at 10 and 30 min in the left eyes (p < 0.05). In the long-term phase, treated eyes showed a significant increase in NIBUT values, a significant reduction of tear evaporation, a significant improvement of tear lipid layer pattern, and a more stable TFOOD compared with baseline (all p < 0.05). Symptoms, measured with the Ocular Surface Disease Index questionnaire, were also significantly reduced compared with baseline (p < 0.05).

CONCLUSION

The tested product increased tear film stability and reduced tear evaporation, normalizing lipid layer pattern and reducing symptoms in the short- and long-term observation.

Evaluation of the effects of vitrectomy with primary epiretinal membrane peel on optical quality using double-pass aberrometry

INTRODUCTION

We performed a prospective, single-center, cohort study in order to evaluate the effects of vitrectomy with epiretinal membrane (ERM) peel on optical quality in patients with primary ERM.

METHODS

Thirty patients treated for primary ERM by vitrectomy with ERM peel were included from our tertiary university hospital ophthalmology department. The main study outcome was variation in optical quality parameters measured using the HD Analyzer™ between pre-operative and two-month post-operative evaluations in operated eyes. Optical quality parameters comprised point spread function (PSF) width at 10% and 50%, objective scatter index (OSI), and modulation transfer function (MTF) cutoff. Contralateral non-operated eyes were used as an internal control for measurement reproducibility.

RESULTS

Mean PSF width at 10% (42.22 vs 27.37 arc/min; p = 0.0002) and mean OSI (3.32 vs 2.32; p = 0.0003) were significantly improved between pre- versus post-operative evaluations. Mean PSF width at 50% and mean MTF cutoff showed no changes. Subgroup analysis according to crystalline lens status gave similar results demonstrating that improvements in mean PSF width at 10% and OSI were not lens-related. Non-operated eyes showed no changes in any of the parameters analyzed.

CONCLUSION

Reduced light scattering measured by OSI indicates improved optical quality following vitrectomy with ERM peel among patients with primary ERM. OSI measurement could thus be a new parameter of interest in the pre-operative assessment of primary ERM and other pre-vitrectomy assessments.

Impact of tear optics on the repeatability of Pentacam AXL wave and iTrace in measuring anterior segment parameters and aberrations

Purpose:

To assess impact of tear optics on repeatability of a Scheimpflug device with a Hartmann Shack aberrometer and a ray tracing aberrometer.

Methods:

One hundred healthy and 100 postrefractive surgery eyes underwent dry eye evaluation including Schirmer’s test and tear film break-up time (TBUT). They underwent optical quality analyzer (OQAS, Visio metrics S.L, Terrassa, Spain) to assess objective scatter index (OSI), three scans each on Pentacam AXL wave (OCULUS Optikgerate Gmbh, Wetzlar, Germany), iTrace (Tracey™ Technologies, Texas, USA) for flat, steep keratometry, thinnest corneal thickness, root mean square higher-order aberrations (RMS HOA), RMS lower-order aberrations (LOA), spherical aberrations, RMS COMA. Repeatability of Pentacam AXL wave and iTrace in healthy and postrefractive eyes (OSI >1 vs OSI <1) was studied using within-subject standard deviation (Sw) test–retest repeatability (TRT), coefficient of variation (COV).

Results:

OSI showed an inverse association with TBUT (P < 0.001). All measurements with Pentacam AXL wave with OSI < 1 had excellent repeatability, intraclass correlation coefficient (ICC) ranging from 0.88 for HOA, to 0.92 for LOA. The Sw, TRT, and COV of all aberration measurements were significantly lower (better) than those of iTrace. In eyes with OSI ≥1, the repeatability with Pentacam AXL wave dropped with ICC ranging from 0.77 for HOA, to 0.84 for LOA with lower Sw, TRT, and COV of all aberration measurements as compared to iTrace. Maximum variation was seen with HOA and minimum with LOA

Conclusion:

Tear optics affected repeatability of Pentacam wave and iTrace. Pentacam wave had better repeatability in eyes with a poor tear film as compared to iTrace. Thus, the tear film can impact repeatability of an instrument and it is important to assess the tear film prior to imaging patients, which can change the way we interpret and image these patients.

Implementation of the Frequency Scatter Index in Clinical Commercially Available Double-pass Systems

A previous work has reported a methodology to quantify intraocular scattering using a high sensitivity double-pass instrument with a robust index, the frequency scatter index. The purpose of our study was to evaluate an adaptation of the frequency scatter index for use in clinical double-pass systems. A prospective observational study was carried out in a group of patients with nuclear cataracts (n = 52) and in a control group (n = 11) using conventional double-pass systems. The frequency scatter index and the objective scatter index were used to assess the scattering. The Spearman coefficient was calculated to assess the correlation between both indexes, obtained from the double-pass images. Simultaneous measurements were performed with a double-pass and with a Hartmann-Shack wavefront sensor in the control group. The root-mean-square wavefront error and the full width at half maximum of the double-pass image were used to quantify the residual aberrations introduced by the variations in pupil size and retinal eccentricity. Measurement in eyes with different grades of cataracts shows a strong correlation (ρ = 0.929, p < .0001) between the frequency scatter index and the objective scatter index. A certain degree of correlation was observed between the objective scatter index and the root-mean-square and between the objective scatter index and the full width at half maximum, both for measurements with a different pupillary diameter and with a different retinal eccentricity (p < .05). No relationship was observed between the frequency scatter index and the root-mean-square or between the frequency scatter index and the full width at half maximum (p > .05). We have introduced and evaluated an adaptation of a methodology proposed recently for the measurement of intraocular scattering using the double-pass technique with a robust index, which is less affected by ocular aberrations. The frequency scatter index can be applied to conventional double-pass instruments available in clinical environments.

Influence of Reading on Smartphone Screens on Visual Optical Quality Metrics and Tear Film Stability

PURPOSE

To evaluate the impact of a prolonged reading session on a smartphone screen on optical quality metrics and tear film stability.

METHODS

This prospective study was conducted in 41 healthy volunteers who were asked to read an article on a smartphone screen for 20 minutes. The following tests were performed before the reading task in this consecutive order and repeated after the reading task in the same order: automated noninvasive tear break-up time, optical quality assessment including Objective Scatter Index (OSI), modulation transfer function, Strehl ratio, and tear film dynamic analysis as follows: vision break-up time (VBUT) as a function of OSI changes within 20 seconds, using a double-pass aberrometer imaging system, and fluorescein tear break-up time (FBUT) measured using the slit lamp.

RESULTS

All break-up time-related parameters (noninvasive tear break-up time, FBUT and VBUT) were significantly reduced after the reading task (P < 0.01). The OSI was significantly worsened after the reading task (P = 0.01), whereas all the other optical quality metrics (modulation transfer function and Strehl ratio) slightly deteriorated, were not statistically significant. A significant correlation was found between the shortening of the FBUT, VBUT, and the worsening of the OSI (r = -0.33, P < 0.05).

CONCLUSIONS

A reading session on a smartphone screen in healthy subjects was found to significantly affect the tear film stability and objectively worsen the retinal image quality.

Visual Performance Following Bilateral Implantation of Refractive Rotationally Asymmetric Bifocal Intraocular Lens (LS-313 MF30) or Apodized Diffractive Bifocal Intraocular Lens (ReSTOR SN6AD1)

Purpose

This study compared the clinical outcomes after cataract surgery with implantation of refractive rotationally asymmetric bifocal intraocular lens (IOL) (LS-313 MF30) and apodized diffractive bifocal IOL (ReSTOR SN6AD1).

Methods

This was a prospective, non-randomized, controlled study, where patients diagnosed with age-related cataracts were selected for phacoemulsification combined with bilateral IOL implantation. Based on the type of IOL voluntarily implanted, the patients were divided into two groups, ie, refractive and diffractive groups. In total, 30 cases (60 eyes) were in a refractive group, while 30 cases (60 eyes) were in diffractive group. Three months after surgery, we examined the uncorrected distance visual acuity (UDVA), uncorrected intermediate visual acuity (UIVA), uncorrected near visual acuity (UNVA), defocus curve, objective visual quality, and subjective questionnaire.

Results

Three months after surgery, the UIVA of the refractive group (0.18 ± 0.08) logMAR was better than that of the diffractive group (0.29 ± 0.16) logMAR (P < 0.05). No significant difference in UDVA and UNVA was noted between the two groups. For a 4mm pupil diameter, the intraocular and total eye aberration, higher-order aberration (HOA), coma, spherical aberration, and trefoil in the refractive group were significantly higher than those in diffractive group (P < 0.05). The intraocular modulation transfer function (MTF), intraocular strehl ratio (SR), total eye MTF, and total eye SR in the refractive group were lower than those in diffractive group (P < 0.05). No significant difference in glare incidence, spectacle independence rate, and patient satisfaction was observed between the two groups (P > 0.05). The halos incidence in the refractive group was lower than the diffractive group (P < 0.05).

Conclusion

Both bifocal IOLs obtained satisfactory UDVA and UNVA, with higher patient satisfaction. Unlike the apodized diffractive bifocal IOL, the refractive rotationally asymmetric bifocal IOL yielded slightly better UIVA, lower halos incidence, whereas the apodized diffractive bifocal IOL showed a better objective visual quality.

Intraocular Scattering, Blinking Rate, and Tear Film Osmolarity After Exposure to Environmental Stress

Purpose

Dry environments, such as those in offices or aircraft cabins, can potentially generate ocular discomfort and alter the tear film. We compare light scatter, blinking rate, and tear osmolarity in young and older subjects after exposure to low humidity using a controlled environmental chamber.

Methods

Two groups of healthy subjects were recruited; younger (N = 13, 27 ± 6 years) and older (N = 23, 71 ± 7 years). Measurements were carried out before and after 90-minute exposure to low relative humidity (5%) and constant temperature (23 degrees). Ocular light scatter was measured using a double-pass instrument (OQAS, Visiometrics, Spain). Blinking rate was monitored using an infrared video camera. Tear osmolarity was measured using the TearLab system (Escondido, CA, USA).

Results

Ocular light scatter increased by a factor of 10% after exposure to low humidity in the older group (P = 0.03) but did not change significantly in the younger group. Blinking rate increased significantly (40% more blinks) in both groups but there was no difference between the groups. No significant differences in osmolarity were shown between two age groups or as result of environmental stress.

Conclusions

Exposure to dry environment increased light scatter in older subjects. Although more blinks were triggered in both younger and older groups to prevent corneal dehydration, there was no difference between the groups. Blink rate and osmolarity are not associated with the difference in light scatter.

Translational Relevance

Our work approaches a clinical care problem using basic research methods (measuring ocular scatter and blink ratio).

Structural Endpoints and Outcome Measures in Uveitis

Most uveitis entities are rare diseases but, taken together, are responsible for 5-10% of worldwide visual impairment which largely affects persons of working age. As with many rare diseases, there is a lack of high-level evidence regarding its clinical management, partly due to a dearth of reliable and objective quantitative endpoints for clinical trials. This review provides an overview of available structural outcome measures for uveitis disease activity and damage in an anatomical order from the anterior to the posterior segment of the eye. While there is a multitude of available structural outcome measures, not all might qualify as endpoints for clinical uveitis trials, and thorough testing of applicability is warranted. Furthermore, a consensus on endpoint definition, standardization, and "core outcomes" is required. As stipulated by regulatory agencies, endpoints should be precisely defined, clinically important, internally consistent, reliable, responsive to treatment, and relevant for the respective subtype of uveitis. Out of all modalities used for assessment of the reviewed structural outcome measures, optical coherence tomography, color fundus photography, fundus autofluorescence, and fluorescein/indocyanine green angiography represent current "core modalities" for reliable and objective quantification of uveitis outcome measures, based on their practical availability and the evidence provided so far.

Bias of near-infrared light in evaluation of patients implanted with multifocal intraocular lenses

PURPOSE

To compare visual quality between subjective tests and optical devices using near-infrared (NIR) light in patients implanted with monofocal, multifocal and enlarged depth-of-focus (EDoF) intraocular lenses (IOLs).

METHODS

Cross-sectional study enrolling patients aged between 55 and 75 (axial length between 22 and 25 mm) bilaterally implanted with Tecnis IOLs (Johnson & Johnson) four months previously: 40 patients (80 eyes) with monofocal ZCB00, 41 patients (82 eyes) with bifocal diffractive ZMB00 and 48 patients (96 eyes) with EDoF Symfony. They were examined using subjective and objective tests. The subjective tests comprised visual acuity (VA) with ETDRS charts, contrast sensitivity (CS) with Pelli-Robson and CSV-1000E tests, and clear vision range (CVR). The objective tests using NIR light were performed with the KR-1 W wavefront analyzer and the OQAS.

RESULTS

In the subjective tests, the monofocal group achieved the best outcomes in some of the VA and CS sections, while the bifocal group obtained the worst outcomes in some of the CS sections. In the objective tests, the bifocal group achieved the best results for VA and CS. Discrepancies between pseudoaccommodation range and CVR were found in the bifocal and EDoF groups.

CONCLUSIONS

Assessment of visual quality using NIR light implies greater bias for diffractive lenses than for EDoF lenses. This bias may be even greater with devices using longer light wavelengths or Hartmann-Shack technology. The difference in wavelength between NIR and visible light leads to dimming of near-vision focus and magnification of distance focus.

Phase IV clinical study to evaluate the effects of an intracameral combined mydriatic and anesthetic agent and standard topical mydriatics and anesthetics on the ocular surface after cataract surgery

PURPOSE

To compare intracameral and topical mydriatics and anesthetics in cataract surgery.

SETTING

Institute of Ocular Microsurgery, Barcelona, Spain.

DESIGN

Phase IV, open-label, randomized, single-center study.

METHODS

Patients were randomized in a 1:1 ratio to receive intracameral mydriatic-anesthetic (Mydrane/Fydrane) and anesthetic eyedrops or control (topical eyedrops only). The other treatment was administered for the second cataract surgery. Assessments were performed at presurgery and immediately postsurgery, at 12 to 36 hours postsurgery (day 1), and 7 days postsurgery. The primary endpoint was the change from baseline in corneal/conjunctival surface staining. The secondary endpoints included assessments of epithelial alterations, point-spread function, ocular surface disease index, conjunctival hyperemia, vision breakup time, ocular symptoms/signs, adverse events (AEs), corrected distance visual acuity, intraocular pressure, patient/investigator satisfaction, and procedure time.

RESULTS

A total of 50 patients undergoing sequential cataract surgery in both eyes were included. Baseline assessments were similar in each group. The difference between Fydrane and control groups for the change from baseline at day 1 in corneal and conjunctival surface staining was not statistically significant. For Fydrane, postoperative epithelial alterations were fewer at day 1 (P < .005), folliculopapillary reaction was less frequent (P < .05), some ocular symptoms were less frequent and milder (P < .05), length of procedure was shorter (P < .001), and patient and investigator satisfaction were better (P < .05). There were few AEs in both groups.

CONCLUSIONS

Fydrane reduced ocular surface damage by decreasing corneal epithelial and conjunctival toxicity with faster recovery of surface integrity compared with topical eyedrops, improved patient and investigator satisfaction, and reduced procedure time.

Visual quality after implantation of trifocal intraocular lenses in highly myopic eyes with different axial lengths

AIM

To analyze postoperative clinical results after implantation of trifocal intraocular lenses (IOLs) in highly myopic eyes with different axial lengths (ALs).

METHODS

This retrospective study describes 61 eyes of 44 patients that were implanted with trifocal diffractive IOLs (AT LISA tri 839MP). Twenty-one eyes (15 patients) were included in the AL<26 mm group, 19 eyes (13 patients) in the AL≥26 mm and <28 mm group, and 21 eyes (16 patients) in the AL≥28 mm group. Postoperative outcomes, including corrected and uncorrected distance visual acuity (UDVA), intermediate and near visual acuity at 167 cd/m² luminance, depth of focus at 85 cd/m² luminance, and objective optical quality parameters assessed using the Optical Quality Analysis System (OQAS), were compared among the groups at 3mo.

RESULTS

There were no significant differences in the mean UDVA, uncorrected intermediate visual acuity, uncorrected near visual acuity, corrected distance visual acuity, distance-corrected intermediate visual acuity, and distance-corrected near visual acuity (DCNVA) among the three groups (P>0.05). Better near and intermediate visual acuity (from -1.5 D to -3.0 D) were noted on the defocus curve of the AL<26 mm group (P<0.01 vs AL≥28 mm group). Significantly higher objective scatter index (OSI) values and lower modulation transfer function (MTF) cut-off values, Strehl ratio (SR), and OQAS values (OVs) were observed in the AL≥28 mm group (P<0.01 vs AL<26 mm group). All OQAS parameters had statistically significant correlations with DCNVA and visual acuity at the vergence of -2.5 D (P<0.05 to P<0.01).

CONCLUSION

Implantation of trifocal IOLs provides good short-term visual and refractive outcomes in highly myopic eyes with different ALs. However, the near vision decreases in the extremely myopic eyes at lower luminance, which is associated with the lower objective optical quality in these eyes.

Functional Optical Zone and Visual Quality After Small-Incision Lenticule Extraction for High Myopic Astigmatism

Introduction

The aim of this study was to compare the functional optical zone (FOZ) after correction of high myopic astigmatism and low myopic astigmatism by small-incision lenticule extraction (SMILE).

Methods

In this prospective study, 30 patients who received SMILE for high myopic astigmatism correction (cylinderical diopters ≤ − 2.0D) were enrolled in the high astigmatism group (HA). The control group comprised 40 patients who underwent SMILE for low myopic astigmatism correction (LA; cylinderical diopters ≥ − 0.5D). FOZ was delineated as the area outlined by a change of 0.5D relative to the power at the corneal vertex on the total corneal refractive power map. An ellipse-fitting program (MatLab) was used to calculate some parameters of the FOZ. Visual quality evaluations were also conducted, including evaluations of wavefront aberrations, optical quality, and intraocular scattering, and completion of a quality of life questionnaire. All of the right eyes were analyzed in the study.

Results

The preoperative average treatment spherical equivalent (− 5.77 ± 1.86D vs. − 6.49 ± 1.49D; P = 0.074), lenticule thickness (120.87 ± 23.27 μm vs. 118.53 ± 21.66 μm; P = 0.666), and programmed optical zone (6.58 ± 0.17 mm vs. 6.65 ± 0.18 mm; P = 0.104) were comparable between the HA and LA groups. The long axes (6.99 ± 1.14 mm vs. 5.32 ± 0.61 mm; P < 0.001), short axes (4.66 ± 0.96 mm vs. 4.23 ± 0.64 mm; P = 0.047), and area (25.90 ± 8.03 mm² vs. 17.92 ± 4.36 mm²; P < 0.001) of the FOZ were significantly larger in the HA group than in the LA group. The centration of the FOZ were comparable between the two groups (0.62 ± 0.25 mm vs. 0.70 ± 0.25 mm; P = 0.194). Postoperative spherical aberration was lower in the HA group than in the LA group (0.07 ± 0.05 μm vs. 0.14 ± 0.10 μm; P = 0.001). There was no significant difference in the ocular scatter index (0.80 ± 0.46 vs. 0.73 ± 0.46; P = 0.447), modulated transfer function (MTF)_cutoff (37.89 ± 9.79 cpd vs. 39.78 ± 7.45 cpd; P = 0.363), and Strehl in two dimensions (Strehl2D) ratio (0.20 ± 0.04 vs. 0.20 ± 0.04; P = 0.363) between the HA group and the LA group. There were no significant differences in the scores on quality of life between the HA and LA groups (45.88 ± 2.15 vs. 45.64 ± 1.84; P = 0.423). Correlation analysis revealed that increase in the spherical aberration was significantly correlated with the long axes, short axes and area in the FOZ in both groups.

Conclusion

With a comparable optical design and attempted correction in SMILE, the eyes with higher myopic astigmatism correction achieved larger FOZ than the eyes with lower myopic astigmatism correction. Consequently, less spherical aberration induction was created after higher myopic astigmatism correction. This result may be associated with less corneal volume sculpted by laser for the higher astigmatism treatment, leading to fewer biochemical responses and les change in corneal aspherity. Good retinal image quality and satisfied quality of life were achieved at a comparable level in both study groups.

Comparison of early visual quality in patients with moderate myopia using different optical zones in small incision lenticule extraction (SMILE)

Background

The early visual qualities of patients with moderate myopia were evaluated after small incision lenticule extraction (SMILE) using different optical zones.

Methods

In this retrospective case study, 27 cases (51 eyes) were selected, including 10 cases in Group A (19 eyes), 6.6–6.8 mm in the optical zone, 10 cases in Group B (19 eyes), 6.4–6.5 mm in the optical zone, and 7 cases in Group C (13 eyes),6.1–6.3 mm in the optical zone. The following items were examined preoperatively and 1 month postoperatively: uncorrected visual acuity (UCVA), best-corrected visual acuity (BCVA), spherical, cylinder, central corneal thickness (CCT), corneal mean curvature (CMC), total ocular aberrations (TA), total low order aberrations (tLOAs), defocus, astigmatism and total high order aberrations (tHOAs), spherical, coma, trefoil, modulation transfer function (MTF), MTF_cutoff, SR, objective scatter index (OSI), point scatter function at 50 and 10% (PSF50%, PSF10%), and contrast visual acuity of 100, 20, and 9% (VA100%, VA20%, and VA9%). We compared the three groups by Kruskal-Wallis test. Wilcoxon signed ranks test was used for each group before and 1 month after surgeries. P< 0.05 was considered statistically significant.

Results

There was no significant difference in UCVA, BCVA, CCT, cylinder, and CMC in three groups preoperatively and 1 month postoperatively (P> 0.05). Comparison of the aberrations of the three groups showed statistically significant difference only in TA, tLOA, defocus, astigmatism and SA preoperatively, and trefoil 1 month postoperatively(P< 0.05). The postoperative TA, tLOAs, defocus, astigmatism and trefoil of the three groups were lower than those before surgeries (P< 0.05). The postoperative tHOAs of Group B and C was lower than those before surgeries (P< 0.05). The MTF results showed that before surgeries, there were significant differences in three groups (P< 0.05) in spatial frequencies 5~15 cycles per degree (cpd), and no differences in 20~30 cpd(P> 0.05), while no difference were observed in all spatial frequencies postoperatively (P> 0.05). Comparing the preoperative and postoperative MTF values for each group, the results showed that there was a significant difference in Group C at 5~20 cpd after surgeries(P< 0.05). There was no significant difference in MTF_cutoff, SR, OSI, PSF50%, PSF10%, VA100%, VA20%, and VA9% in the three groups preoperatively (P> 0.05). One month after surgeries, higher VA9% values were measured for Group C compared to Group A and B (P < 0.05). There was no significant difference in each group before and after surgeries (P> 0.05).

Conclusion

SMILE could improve the visual qualities of patients with moderate myopia. Reducing the surgical optical zone will only affect night vision slightly.

Utility of the optical quality analysis system for decision-making in Nd: YAG laser posterior capsulotomy in patients with light posterior capsule opacity

Background

A prospective cohort study was performed to evaluate whether the Optical Quality Analysis System (OQAS) can serve as a valuable additional indicator for appropriate posterior capsulotomy referral.

Methods

One hundred and five eyes from 96 patients undergoing capsulotomy were divided into precapsulotomy logMAR CDVA ≤0.1 group and logMAR CDVA > 0.1 group. CDVA, and the Visual Function 14 index (VF-14) score were estimated before and 1 month after capsulotomy. The objective scattering index (OSI) value was measured by using the OQAS. Posterior capsule opacification (PCO) severity was assessed with Evaluation of PCO 2000 (EPCO 2000) software.

Results

In logMAR CDVA > 0.1 group, the correlations of OSI, logMAR CDVA, EPCO score and VF-14 score were very strong preoperatively. In logMAR CDVA ≤0.1 group, preoperatively, OSI was correlated with logMAR CDVA (r = 0.451), EPCO score (r = 0.789), and VF-14 score (r = 0.852). LogMAR CDVA has weak correlation with VF-14 score (r = − 0.384) and EPCO score (r = 0.566). VF-14 score was correlated with EPCO score (r = − 0.669). In the logMAR CDVA ≤0.1 group, there was no significant difference in logMAR CDVA between precapsulotomy and postcapsulotomy (P > 0.05). In the two groups, all the other optical quality parameters were significantly improved after capsulotomy (P < 0.05). In logMAR CDVA > 0.1 group, the area under the curve of the ROC of the OSI was 0.996 (P = 0.000). In logMAR CDVA ≤0.1 group, the area under the curve of the ROC of the OSI was 0.943 (P = 0.000).

Conclusions

The OSI was useful for evaluating of PCO and prediction of beneficial capsulotomy. Especially for patients with slight PCO and better visual acuity, OSI is more valuable than CDVA and completely objective examination.

Trial registration

The study protocol was registered at the Chinese Clinical Trial Registry. Register: ChiCTR1800018842 (Registered Date: October 13th, 2018).

A comparative study on early vision quality after implantation of refractive segmental and diffractive multifocal intraocular lens

Objectives:

To compare early subjective and objective vision quality of postoperative patients undergoing phacoemulsification cataract surgery combined with implantation of refractive segmental multifocal intraocular lens (MIOL) SBL-3 and apodized diffractive MIOL SN6AD1.

Methods:

As a prospective study, it enrolled 53 patients (53 eyes) to undergo phacoemulsification cataract surgery combined with MIOL implantation. According to differences in MIOL implanted, patients were divided into a SBL-3 group (25 eyes) and a SN6AD1 group (28 eyes). Ophthalmological evaluation included uncorrected (UDVA) and corrected (CDVA) distance visual acuities, uncorrected intermediate (UIVA) and near (UNVA) visual acuities, distance-corrected intermediate (DCIVA) and near (DCNVA)visual acuities and corrected near(CNVA) visual acuity, contrast sensitivity, modulation transfer function (MTF) and high order aberration (4 mm pupil diameter) at three months postoperatively. Moreover, a questionnaire survey was carried out to assess near spectacle independence, patient satisfaction and symptoms of visual disturbance.

Results:

At three months after surgery, UIVA and UNVA in the SBL-3 group are statistically significantly superior to those of the SN6AD1 group (P>0.05). There was statistical difference in contrast sensitivity at four spatial frequencies (3, 6, 12, 18cycles/degree) under mesopic conditions and mesopic conditions with glare (P>0.05). The total ocular high order aberration, coma and trefoil were statistically significantly larger in the SBL-3 group than in the SN6AD1 group with 4.0 mm pupil diameters (P>0.05). Statistical differences were found in the MTF at spatial frequencies of 5, 10 and 15 cycles/degree between the groups. There were no significant differences in spectacle independence, patient satisfaction and visual disturbance between the groups (P>0.05).

Conclusions:

Both the two multifocal intraocular lens provided an excellent level of quality of vision three months postoperatively. However, the application effect of SBL-3 MIOL is superior to that of SN6AD1 MIOL as far as intermediate vision, near vision and contrast sensitivity are concerned.

Using Optical Quality Analysis System for predicting surgical parameters in age-related cataract patients

The Optical Quality Analysis System (OQAS, Visiometrics) provides objective measurements of image formed onto retina, by combining quantification of ocular media transparency and of optical aberrations. In order to evaluate its contribution in the assessment of age-related cataract, we conducted a monocentric clinical study to determine the relationships between clinical grading of lens opacity, OQAS parameters, and parameters required for cataract surgery by phacoemulsification with ultrasound (called “phacodynamics”). Clinical parameters were: best-corrected visual acuity (BCVA, expressed as Log of minimal angle resolution (logMAR)) and the lens opacity classification system III (LOCS III) as a gold standard determined by two independent observers who graded total cataract and nuclear, cortical and posterior sub capsular components. The OQAS provided an objective scatter index (OSI), a modulation transfer function (MTF, expressed in cycle per degree (cpd)) and a Strehl ratio (SR) used as an aberration marker. Patients were operated on by the same surgeon using a phacoemulsification machine that provided the cumulative dissipated energy (CDE) and total ultrasound time (US time) necessary to extract the lens. Patients with poor compliance, corneal or retinal diseases impairing OSI, or who required surgical settings variation, were excluded. Twenty-one eyes of 21 patients aged 76±8 years were analyzed. They were 11 pure nuclear, 3 pure cortical, and 7 mixed cataracts. Mean LOCS III and OSI were respectively: 4.86 ±2.03 and 6.12 ±3.07 (mean±SD). Medians (10°-90° percentiles) were: for BCVA 0.30 (0.10–0.70) logMAR, for MTF cutoff 9.31 (1.54–30.57) cpd, for SR 0.071 (0.042–0.146), for CDE 8.04 (5.74–23.29) and for US time 58 (39–116) seconds. LOCS III was significantly correlated (spearman r, r_s) with BCVA (r_s = 0.561, p = 0.008), CDE (r_s = 0.457, p = 0.038) and US time (r_s = 0.647, p = 0.002). The three OQAS parameters significantly correlated (all r_s ≥ 0.526, p<0.05) with BCVA, and LOCS III grading, but the strongest correlations were found with OSI for cortical components and with MTF for nuclear components: only OSI may be used objectively to assess the effect of cortical components on optical quality, and MTF cutoff—integrating scattering and aberrations—seems the best objective parameter for clinical assessment of nuclear cataracts. The three OQAS parameters were also significantly correlated (r_s) with CDE, and with US time only for pure nuclear cataracts: OSI had the strongest correlations with phacodynamics (r_s = 0.693, p = 0.022 with CDE and r_s = 0.703, p = 0.019 US time). OSI increased with cortical components not requiring higher CDE. When measured in optimal conditions (good compliance, no retinal or ocular surface or tear film diseases), the three OQAS parameters are complementary for objective grading of cataract. In the future, they may help to optimize surgical parameters, especially energy distribution, in femtosecond laser assisted cataract surgery.

Relationships Between Haloes and Objective Visual Quality in Healthy Eyes

Purpose

To determine the normal values and relationships between haloes and objective optical quality in healthy eyes.

Methods

In this cross-sectional study, haloes, pupillary responses to light, and objective optical quality were measured with the optical quality analysis system (OQAS) and a vision monitor (MonCv3) in 138 right eyes of 138 healthy young men with mean spherical equivalent of 0.32 ± 0.47 D.

Results

The mean disc halo size was 77.17 ± 25.03 arcmin. The mean objective optical quality values were as follows: objective scatter index (OSI), 0.58 ± 0.33; Strehl ratio (SR), 0.21 ± 0.05; modulation transfer function cutoff, 36.27 ± 7.98 cpd; OQAS value (OV)100%, 1.21 ± 0.27; OV20%, 0.91 ± 0.23; and OV9%, 0.59 ± 0.16. Disc halo size correlated independently with OSI (P < 0.001) and minimum pupil size (P = 0.003) by forward stepwise regression analysis (disc halo size = 16.60 + 26.24 × OSI + 11.34 × minimum pupil size; R² value = 17.7%; F = 14.52; P < 0.001).

Conclusions

Reference values for disc halo size and objective optical quality in healthy young subjects were established. Eyes with worse objective vision quality exhibited larger haloes.

Translational Relevance

The study provided the knowledge and the relationships of OQAS and halo measurements from a well-defined group of healthy young subjects. Both measurements are useful in clinical practice to help quantify the vision quality and complement each other.

Real dynamic assessment of tear film optical quality for monitoring and early prevention of dry eye

To evaluate real dynamic assessment of tear film optical quality for monitoring and prevention of dry eye.Right eyes of 62 normal and 39 dry eye subjects were included. Dynamic measurement of objective scatter index (OSI) was performed by using the Optical Quality Analysis System II (OQAS II), correlation coefficient between OSI and time (CCOT) was calculated. According to whether the CCOT was significantly ascending, normal and dry eye groups were further subdivided for comparison. By using Scheimpflug-Placido topographer, non-invasive tear break-up time (NITBUT) was recorded, and a 2-dimensional precorneal tear film map was reconstructed and divided into central, middle, and peripheral corneal zones, distribution of tear break-up spots in the 3 corneal zones were analyzed.The numbers of tear break-up spots were higher in all the 3 corneal zones of the dry eye subjects (P < .01), when compared with the normal subjects. The Dry Eye subjects with ascending CCOT had the shortest NITBUT (P < .001-.034) and the most tear break-up spots over the whole cornea (P < .001-.044). Between the dry eye subjects with non-ascending CCOT and those with ascending CCOT, difference of tear break-up spots was found significant only in the peripheral corneal zone (P < .01).Non-ascending and ascending CCOT of dry eye patients reflect different stability of tear film. Real dynamic assessment of tear film optical quality is potential for monitoring and early prevention of dry eye.

Comparative Analysis of Visual Performance and Optical Quality with a Rotationally Asymmetric Multifocal Intraocular Lens and an Apodized Diffractive Multifocal Intraocular Lens

Purpose

To compare the short-term visual outcomes and intraocular optical performance of a rotationally asymmetric multifocal intraocular lens (MIOL) (SBL-3, Lenstec, Inc., Christ Church, Barbados) and an apodized diffractive MIOL (the Acrysof IQ ResTOR SN6AD1, Alcon Laboratories, Inc., Fort Worth, Texas, United States).

Methods

A prospective, comparative, nonrandomized, and single-center study. Sixty-eight age-related cataract patients (81 eyes) after phacoemulsification cataract surgery and in-the-bag MIOL implantation were enrolled. Thirty-eight eyes received SBL-3, and 43 eyes received SN6AD1. Ophthalmological evaluation included uncorrected distance visual acuity (UDVA), uncorrected intermediate visual acuity (UIVA), uncorrected near visual acuity (UNVA), corrected distance visual acuity (CDVA), modulation transfer function (MTF), Strehl ratio (SR), intraocular aberrations (4 mm optical zone), and defocus curve at 3 months postoperatively. The Chinese version of the visual function index-14 (VF-12-CN) and spectacle independence were assessed in all patients.

Results

There was no statistically significant difference between groups in postoperative UDVA (p = 0.186). Postoperative UIVA and UNVA were significantly better for the SBL-3 group than for the SN6AD1 group (p < 0.01). Statistically significant differences were revealed in defocus levels from –3.50 D to −4.00 D with better visual acuities for the SBL-3 group (p < 0.01). For intraocular optical quality outcomes, statistically significant differences between groups were observed in RMS of intraocular total aberrations, coma, and trefoil high-order aberrations, presenting significantly higher values of these parameters in the eyes of the SBL-3 group (p < 0.01). Statistically significant differences were revealed in the MTF values at spatial frequencies of 5 and 10 cycles/degree between groups. There were no significant differences in scores of VF-12-CN, and spectacle independence between the groups (p > 0.05).

Conclusions

Both MIOLs were able to successfully restore visual function after cataract surgery. SBL-3 provided better UIVA and UNVA with a wider range of intermediate vision.

Assessment of Visual Quality in Eyes with Forme Fruste Keratoconus and Mild and Moderate Keratoconus Based on Optical Quality Analysis System II Parameters

Purpose

The study aimed to evaluate the visual quality of forme fruste keratoconus (FFK) and mild and moderate keratoconus by using an optical quality analysis system II (OQAS-II) and to explore the correlation between optical quality parameters and the disease progression.

Methods

Twenty-one normal eyes, twenty-one FFK eyes, twenty-one mild keratoconus eyes, and twenty-one moderate keratoconus eyes were included in this prospective study. The optical quality parameters, such as object scatter index (OSI), modulation transfer function cutoff (MTF cutoff), strehl ratio (SR), and OQAS-II values at contrasts of 100% (OV-100), 20% (OV-20), and 9% (OV-9), were measured by OQAS-II. The repeatability of these parameters was analyzed by intraclass correlation coefficient (ICC), repeatability coefficient (RC), and coefficient of variation (CV_w). Correlations between optical quality parameters and mean central keratometry readings (K_mean) were evaluated. The sensitivity and specificity of the parameters were analyzed using the receiver operating characteristic (ROC).

Results

All the optical quality parameters among four groups showed good repeatability (all ICC≥0.75). The MTF cutoff, SR, OV-100, OV-20, OV-9 in FFK, mild and moderate keratoconus eyes were significantly lower than those in the normal group (all P < 0.05). The ROC analyses of the MTF cutoff, SR, OV-100, OV-20, and OV-9 showed significant area under the curve (AUC) in discriminating FFK form normal, mild keratoconus from FFK, and moderate keratoconus from mild keratoconus (all P < 0.05). The ROC analyses of the MTF cutoff, SR, OV-100, OV-20, and OV-9 showed significant area under the curve (AUC) in discriminating FFK form normal, mild keratoconus from FFK, and moderate keratoconus from mild keratoconus (all P < 0.05). The ROC analyses of the MTF cutoff, SR, OV-100, OV-20, and OV-9 showed significant area under the curve (AUC) in discriminating FFK form normal, mild keratoconus from FFK, and moderate keratoconus from mild keratoconus (all P < 0.05). The ROC analyses of the MTF cutoff, SR, OV-100, OV-20, and OV-9 showed significant area under the curve (AUC) in discriminating FFK form normal, mild keratoconus from FFK, and moderate keratoconus from mild keratoconus (all P < 0.05). The ROC analyses of the MTF cutoff, SR, OV-100, OV-20, and OV-9 showed significant area under the curve (AUC) in discriminating FFK form normal, mild keratoconus from FFK, and moderate keratoconus from mild keratoconus (all K_mean) were evaluated. The sensitivity and specificity of the parameters were analyzed using the receiver operating characteristic (ROC). r = −0.710, P < 0.05). The ROC analyses of the MTF cutoff, SR, OV-100, OV-20, and OV-9 showed significant area under the curve (AUC) in discriminating FFK form normal, mild keratoconus from FFK, and moderate keratoconus from mild keratoconus (all

Conclusion

The repeatability of OQAS-II is good in measuring visual quality of normal as well as FFK, mild, and moderate keratoconus. The visual quality of the FFK, mild, and moderate keratoconus is worse than that in normal eyes. The OQAS-II has the potential value in screening FFK from normal eyes and might be a useful tool for evaluating the progression of keratoconus.

Optical quality assessment in branch retinal vein occlusion after monthly intravitreal ranibizumab injection: a prospective, case-control study

PURPOSE

To evaluate optical quality and intraocular scattering using the Optical Quality Analysis System (OQAS) II in branch retinal vein occlusion (BRVO) and to investigate the influences of retinal changes on optical quality.

MATERIALS AND METHODS

Sixty-two patients with diagnosis of BRVO were enrolled in this prospective, case-control study. The control group consisted of the patients' fellow eyes. Initial logMAR visual acuity, central macular thickness, and optical quality parameters including modulation transfer function cutoff frequency (MTF cut off), Strehl ratio (SR), objective scatter index (OSI) and OQAS values (OVs) at 100%, 20%, and 9% contrast levels were measured. Every BRVO-affected eye was treated with monthly intravitreal ranibizumab injection. We investigated the differences between clinical parameters of the BRVO-affected eye and those of the control eye and changes in those parameters on the basis of the clinical course of BRVO over 3 months.

RESULTS

All the OQAS parameters measured except objective refraction error differed statistically significantly between the two groups. As macular thickness decreased and visual acuity improved, all the optical quality parameters except for objective refraction error and OV at 100% contrast gradually recovered with time after treatment but did not return to normal compared with the control eye. Only visual acuity was found to be significantly related to central macular thickness change (p = .027).

CONCLUSIONS

BRVO resulted in declined visual acuity and optical quality. It is suggested that the optical quality parameters are affected by the inner layers of the retina in BRVO.

Quantification of forward scattering based on the analysis of double-pass images in the frequency domain

Purpose

To assess forward intraocular scattering by means of a new parameter (Frequency Scatter Index, FSI₃) based on the analysing double‐pass retinal images in the frequency domain, which minimizes the impact of aberrations on the results.

Methods

A prospective observational study was carried out in the Department of Ophthalmology, Hospital Universitari Mútua de Terrassa (Spain) on a group of 19 patients diagnosed with nuclear cataracts of various LOCSIII grades and a control group (CG) with nine healthy eyes. We recorded double‐pass retinal images with a custom set‐up based on a high‐sensitivity digital camera. The FSI₃ was then computed using spatial frequencies below three cycles per degree. A preliminary validation of the FSI₃ was performed on an artificial eye and two eyes of volunteers with and without commercial diffusers, and under defocus.

Results

The FSI₃ was hardly affected by defocus values up to 2.50 D. The mean (and standard deviation) FSI₃ values were as follows: for the CG, 1.19 (0.21); and for LOCSIII grades nuclear opacity 1, 2 and 3, 1.30 (0.12), 1.62 (0.21) and 1.85 (0.21), respectively. Eyes with cataracts showed FSI₃ values significantly different than healthy eyes (p = 0.001). A good correlation (ρ = 0.861, p < 0.001) was found between the FSI₃ and objective scatter index provided by a commercial instrument.

Conclusion

Since aberrations have little impact on the FSI₃, the light scatter assessment becomes less dependent on the patient's refractive error compensation and the presence of higher‐order aberrations. The FSI₃ can further the clinical and scientific understanding of forward intraocular scattering.

Optical quality in low astigmatic eyes with or without cylindrical correction

PURPOSE

To investigate whether optical quality could be improved by cylindrical correction for low astigmatic eyes with different amounts and axis orientations in patients with myopia up to - 3.00 diopters (D).

METHODS

A cross-sectional study enrolling healthy young eyes with 0 to - 3.00 D myopia and - 0.50 to - 0.75 D myopic astigmatism was implemented. With a repeated-measures design, outcome measures were sequentially obtained for each subject under two correction modalities: spherocylindrical correction and spherical correction. Subjective refraction was used to determine the refractive prescriptions accordingly in the two correction modalities to obtain optimal subject-reported visual acuity. Primary outcomes were optical quality parameters including objective scatter index (OSI), modulation transfer function (MTF) cut-off, Strehl ratio (SR), and a simulated contrast visual acuity-optical quality analysis system (OQAS) values (OV) obtained by a double-pass system. Corrected distance visual acuity (CDVA) was measured as a secondary outcome. Outcome comparisons between the two correction modalities were performed by grouping in different amounts (- 0.50 D, - 0.75 D) and axes (with the rule, WTR; against the rule, ATR; oblique, OBL) of astigmatism.

RESULTS

A total of 194 eyes of 194 subjects were evaluated. Significantly better CDVA were shown by spherocylindrical correction for all types of astigmatism except for - 0.50 D WTR astigmatism (P = 0.831). For eyes with - 0.50 D WTR astigmatism, better outcome was only shown in OSI with spherocylindrical correction (P = 0.019). For eyes with - 0.50 D ATR and OBL astigmatism, spherocylindrical correction demonstrated better outcomes in all parameters except for SR (P > 0.05). For eyes with - 0.75 D astigmatism, significantly better outcomes in all optical quality parameters were shown with spherocylindrical correction regardless of the axis (P < 0.05).

CONCLUSIONS

Eyes with ATR or OBL myopic astigmatism may benefit in optical quality and visual acuity by combining a cylindrical correction even with a low amount down to - 0.50 D. However, optical quality and visual acuity improvement are limited for WTR astigmatic eyes when the amount of astigmatism is less than - 0.75 D.

Improved Machine Learning Approach for Wavefront Sensing

In the adaptive optics (AO) system, to improve the effectiveness and accuracy of wavefront sensing-less technology, a phase-based sensing approach using machine learning is proposed. In contrast to the traditional gradient-based optimization methods, the model we designed is based on an improved convolutional neural network. Specifically, the deconvolution layer, which reconstructs unknown input by measuring output, is introduced to represent the phase maps of the point spread functions at the in focus and defocus planes. The improved convolutional neural network is utilized to establish the nonlinear mapping between the input point spread functions and the corresponding phase maps of the optical system. Once well trained, the model can directly output the aberration map of the optical system with good precision. Adequate simulations and experiments are introduced to demonstrate the accuracy and real-time performance of the proposed method. The simulations show that even when atmospheric conditions D/r₀ = 20, the detection root-mean-square of wavefront error of the proposed method is 0.1307 λ, which has a better accuracy than existing neural networks. When D/r₀ = 15 and 10, the root-mean-square error is respectively 0.0909 λ and 0.0718 λ. It has certain applicative value in the case of medium and weak turbulence. The root-mean-square error of experiment results with D/r₀ = 20 is 0.1304 λ, proving the correctness of simulations. Moreover, this method only needs 12 ms to accomplish the calculation and it has broad prospects for real-time wavefront sensing.

Objective optical quality in eyes with customized selection of aspheric intraocular lens implantation

BACKGROUND

To compare the postoperative optical quality in eyes with customized selection and random selection of aspheric intraocular lens (IOL) implantation.

METHODS

A prospective, nonrandomized study was implemented in adult cataract patients who underwent unilateral phacoemulsification with aspheric IOL implantation. Patients were allocated into two treatment groups: a customized group and a control group. In the customized group, the aspheric IOL selection was based on the corneal spherical aberration to enable the postoperative target ocular spherical aberration closest to zero; in the control group, the aspheric IOLs were chosen using a random strategy. Primary outcome measurements included the following objective optical quality assessments: higher-order aberrations obtained by a Hartmann-shack aberrometer at 4 mm and 6 mm pupil diameters; objective scatter index (OSI), modulation transfer function (MTF) cut-off, Strehl ratio (SR) and a simulated contrast visual acuity-optical quality analysis system value (OV) obtained by a double-pass system with a 4-mm aperture. Subjective visual acuity was measured as secondary outcome. All the patients were followed up for 3 months.

RESULTS

Eighty-four patients in the customized group and 78 patients in the control group were evaluated. There was no significant difference in postoperative visual acuity between the two groups (P > 0.05). Significantly less ocular higher-order aberrations were shown in the customized group (P < 0.05). No significant difference was shown in OSI, MTF cut-off, SR and OV between the two groups (P > 0.05).

CONCLUSIONS

Although customized selection of aspheric IOL implantation showed less postoperative ocular aberrations, it performed similarly to random selection of aspheric IOL implantation in terms of postoperative visual acuity, simulated contrast visual acuity, intraocular scatter, modulation transfer function and Strehl ratio.

TRIAL REGISTRATION

Retrospectively registered on 07/06/2019. Registration number: ChiCTR1900024356 .

Optical Quality Assessment in Patients with Macular Diseases Using Optical Quality Analysis System

Macular diseases cause vision loss, as the macula is the functional center for vision. In this study we assessed optical quality in eyes with macular diseases and evaluated the effectiveness of the Optical Quality Analysis System (OQAS) to detect macular diseases. We analyzed 88 eyes of 88 patients with macular diseases (51 men and 37 women; mean age: 65.24 ± 12.96 years) and 43 eyes of 43 control subjects (11 men and 32 women; mean age: 54.70 ± 15.03 years). The macular diseases included age-related macular disease (n = 62), diabetic macular edema (n = 19), and retinal vein occlusion (n = 7). We measured the objective scattering index (OSI), modulation transfer function (MTF), Strehl ratio, and predicted visual acuities (PVAs) at 100, 20, and 10% contrast levels in both groups using OQAS. We measured the retinal thickness in the macular disease group on optical coherence tomography. The macular disease and control groups significantly differed in OSI, MTF, Strehl ratio, and PVAs at 20 and 10% contrast levels (p < 0.05). In the macular disease group, retinal thickness correlated with OSI (r = 0.370, p < 0.001) and MTF (r = -0.264, p = 0.014). In conclusion, optical quality was worse in the patients with macular diseases compared to the control subjects, and retinal thickness affected optical quality. Therefore, the distortion of macular shape may contribute to vision disturbance in patients with macular diseases.

Comprehensive Evaluation of Retinal Image Quality in Comparing Different Aspheric to Spherical Intraocular Lens Implants

Purpose: To compare the visual and optical quality of eyes implanted with three aspheric versus two spherical intraocular lenses (IOL) after cataract surgery. Methods: This prospective comparative study included 349 eyes of 349 patients with age-related cataract and undergone uneventful phacoemulsification. Implanted posterior monofocal IOLs have an aspheric optic (Tecnis ZCB00 [Johnson & Johnson Vision], Acrysof IQ SN60WF [Alcon], Akreos AO [Bausch & Lomb]) or a spherical optic (Akreos [Bausch & Lomb], Sensar AR40e [Johnson & Johnson Vision]). Postoperatively, objective optical quality parameters were performed using an Optical Quality Analysis System II (Visiometrics), and wave-front aberrations were assessed using a KR-1W aberrometer (Topcon). Meanwhile, subjective visual acuity was performed using a logarithm of the minimum angle of resolution chart at 3 months after cataract surgery. Results: Statistical significant differences (P < .05) across all groups were found regarding intraocular and total ocular spherical aberration (SA) at 4.0 mm and 6.0 mm pupil diameter and total high-order aberration (tHOA) at 6.0 mm pupil diameter. Furthermore, differences among the evaluated groups were observed regarding several objective parameters such as objective scatter index (OSI), modulation transfer function cutoff (MTF cutoff), Strehl ratio (SR) at two dimensions and contrast visual acuity (OV) at three contrast levels. Conclusions: The present results reflect the optical characteristics of IOL in vivo. The scattering light and high-order aberration may be the main reasons for the degradation of retinal imaging quality in comparing different aspheric to spherical IOL implants.

Evaluation of Visual Quality in Pseudophakic Eyes with Different Ocular Spherical Aberrations

Purpose: To evaluate the effects of different residual total ocular spherical aberration (SA) on objective and subjective visual quality in pseudophakic eyes. Methods: This prospective consecutive study comprised 171 patients with age-related cataract and undergone unilateral uneventful phacoemulsification. All participants were divided into four groups based on residual ocular SA at 6 mm pupil: negative SA (≤-0.10 μm, group A), neutral SA (0.00 ± 0.05 μm, group B), slightly positive SA (0.10 ± 0.05 μm, group C), and more positive SA (0.20 μm, group D), respectively. Subjective visual acuity and contrast sensitivity, and objective optical quality and ocular aberrations were analyzed 3 months postoperatively. Results: There was no significant difference in baseline measurements across all groups. Postoperatively, no statistically significant differences were found in visual acuity between groups (P > .05), while differences reached statistical significance in mesopic contrast sensitivity at 12 and 18 cpd (P < .01). There were significant differences in ocular SA and higher-order aberrations at 6 mm pupil, as well as in optical quality parameters (P < .05). Group C showed a minimum value of objective scatter index (1.17 ± 0.55) but maximum values of modulation transfer function cutoff (31.94 ± 9.18) and optical quality value OV 100% (1.07 ± 0.31), indicating lower intraocular scattering and superior optical quality. Conclusions: This comprehensive evaluation is conducive to deepening the understanding of visual and optical performance of pseudophakic eye. A modest amount of positive ocular SA seemed to be a more preferable option for enhancing visual quality after aspheric ntraocular lense (IOL) implantation.

Tear-film dynamics by combining double-pass images, pupil retro-illumination, and contrast sensitivity

Tear-film dynamics were analyzed by a synchronizing recording of double-pass (DP) and pupil retro-illumination (RI) images with contrast sensitivity (CS) measurements. Simultaneous DP and RI images were acquired in three subjects wearing contact lenses while keeping the eye open. Changes in contrast sensitivity for an 18 c/deg green grating were also estimated. From the DP retinal images, the effect of the tear film is described through the objective scattering index (OSI). This presented a negative correlation with the increase in CS during tear-film deterioration (as observed by RI imaging). These results show a relationship between visual outcome degradation due to tear-film breakup and the increase in intraocular scattering. This work shows a combined methodology for the evaluation of tear-film dynamics.

[Tear film analysis and evaluation of optical quality: A review of the literature (French translation of the article)]

Dry eye is a complex multifactorial disease of the ocular surface and tears. It is associated with ocular surface symptoms and is one of the most common causes for ophthalmologic consultation. Despite their frequent use in clinical practice, the usual tests to evaluate dry eye and ocular surface disease-history of symptoms, tear break-up time (TBUT), Meibomian gland evaluation, corneal fluorescein staining, Schirmer test-have shown low reproducibility and reliability. In addition, subjective symptoms are often weakly or poorly correlated with objective signs. Since the tear film is the first system through which light must pass, the optical quality of the eye is highly dependent on the homogeneity of the tear film. Various investigative methods have been developed to evaluate both the structural and functional quality of the tear film, such as corneal topography, interferometry, tear meniscus measurement, evaporation rate, tear osmolarity and even aberrometry. Some are easily accessible to clinicians, while others remain in the field of clinical research. All of these tests provide a better understanding of the pathophysiology of the tear film. This review hopes to provide an overview of the existing tests and their role in evaluating the significance of the tear film in visual function.

Tear film analysis and evaluation of optical quality: A review of the literature

Dry eye is a complex multifactorial disease of the ocular surface and tears. It is associated with ocular surface symptoms and is one of the most common causes for ophthalmologic consultation. Despite their frequent use in clinical practice, the usual tests to evaluate dry eye and ocular surface disease-history of symptoms, tear break-up time (TBUT), Meibomian gland evaluation, corneal fluorescein staining, Schirmer test-have shown low reproducibility and reliability. In addition, subjective symptoms are often weakly or poorly correlated with objective signs. Since the tear film is the first system through which light must pass, the optical quality of the eye is highly dependent on the homogeneity of the tear film. Various investigative methods have been developed to evaluate both the structural and functional quality of the tear film, such as corneal topography, interferometry, tear meniscus measurement, evaporation rate, tear osmolarity and even aberrometry. Some are easily accessible to clinicians, while others remain in the field of clinical research. All of these tests provide a better understanding of the pathophysiology of the tear film. This review hopes to provide an overview of the existing tests and their role in evaluating the significance of the tear film in visual function.

Changes and Diurnal Variation of Visual Quality after Orthokeratology in Myopic Children

Purpose

To assess the changes and the diurnal variation of visual quality after orthokeratology in myopic children.

Methods

Forty-four eyes of 22 subjects with a mean age of 10.55 ± 1.53 years (8 to 14 years) were enrolled in this prospective study. Their spherical equivalent ranged from -1.25 to -4.25 diopters (D) and astigmatism was less than 1.00 D. Parameters including corneal curvature, ocular objective scatter index (OSI), the modulation transfer function (MTF), root mean square of ocular and corneal wavefront aberrations, and contrast sensitivity function (CSF) were measured before and at two time points during the same day after 1 month of orthokeratology.

Results

After orthokeratology, uncorrected visual acuity (UCVA) and spherical equivalent were significantly improved from baseline (P < 0.001), and their diurnal variation was not significant (P=0.083, 0.568). OSI increased from 0.29 ± 0.15 to 0.65 ± 0.31 (P < 0.001). MTF decreased significantly (P < 0.01). Corneal curvature and ocular total aberration decreased (P < 0.001), while the ocular and corneal higher-order aberration increased significantly (P < 0.01). The CSF under photopic condition decreased at 3 cpd (P=0.006) and increased at 18 cpd (P=0.012). The diurnal variation of CSF at 18 cpd under mesopic and high glare conditions and at 12 cpd under photopic condition was significant (P=0.002, 0.01, 0.017).

Conclusions

Orthokeratology can effectively improve UCVA and high spatial frequency CSF by decreasing the low-order aberrations. However, MTF and CSF at low spatial frequency decreased because of the increase of intraocular scattering and high-order aberrations. Meanwhile, CSF at high spatial frequency fluctuates significantly at two times during the same day after 1 month orthokeratology.

System based on the contrast of Purkinje images to measure corneal and lens scattering

Current methods to measure intraocular scattering provide information on the total scattered light, which consists of the combined contributions originating from different ocular structures. In this work, we propose a technique for the objective and independent assessment of scattering caused by the cornea and the lens based on the analysis of the contrast of the third and fourth Purkinje images. The technique is preliminarily validated first by using artificial eyes with different levels of corneal and lens scattering; second, it is validated in eyes wearing customized contact lenses to simulate corneal scattering and eyes with nuclear cataracts. Finally, it is tested on a larger population of eyes with cataracts and corneal disorders to prove its clinical usefulness.

Utility of the optical quality analysis system for decision-making in cataract surgery

BACKGROUND

A cataract is a common cause of vision impairment that requires surgery in older subjects. The Optical Quality Analysis System (OQAS, Visiometrics SL, Terrassa, Spain) assesses the optical quality of the eye in cataract patients. This study shows the role of the optical quality evaluation system for decision-making in cataract surgery. We investigated the clinical utility of the OQAS for decision-making in cataract surgery.

METHODS

Sixty-seven eyes from 67 patients undergoing cataract surgery and 109 eyes from 109 control subjects were compared. The best corrected visual acuity (BCVA) was measured. The objective scatter index (OSI), modulation transfer function (MTF), Strehl ratio, predicted visual acuity (PVA) 100%, PVA 20%, and PVA 10% were measured using the OQAS. The sensitivity and specificity of the different parameters were analyzed using the receiver operating characteristic (ROC) curve. The main parameters measured were sensitivity and specificity.

RESULTS

The BCVA, OSI, PVA 100%, PVA 20%, and PVA 10% were higher in the cataract group compared to those in the control group, while the MTF and Strehl ratios were lower (p <  0.001 for all). ROC analysis showed that the OSI had the largest area under the curve and that the sensitivity and specificity of the OSI were 83.9 and 84.6%, respectively, at the optimal cut-off point of 2.35.

CONCLUSION

The MTF, OSI, Strehl ratio, PVA 100%, PVA 20% and PVA 10% may be useful parameters for preoperative decision-making in cataract surgery. The OSI appears to be the most effective parameter for this purpose.

Driver distraction by smartphone use (WhatsApp) in different age groups

This paper investigates the effect that texting with WhatsApp, one of the most common applications for instant messaging, exerts on driving performance. Because distracted driving also affects older drivers, who can have seriously compromised vision, we also analysed the associations between visual-function parameters and driving performance. A total of 75 drivers, experienced in sending WhatsApp messages (≥10WhatsApp messages/week), participated in this study and were divided into four age categories. Visual-function tests included contrast sensitivity with and without glare, retinal straylight and objective assessment of optical quality. Simulated driving performance was assessed under a baseline driving condition (without distraction) as well as a texting condition (WhatsApp messages) while driving. The participants used their own mobile phone. Lastly, objective results of driving performance were compared with subjective self-report data from the Driver Behaviour Questionnaire (DBQ). The analysis indicated that functional changes occurring with age, such as a lower contrast sensitivity and greater retinal straylight, were correlated with a higher number of collisions, longer distances driven outside the lane, and greater standard deviation of lateral position (SDLP). The results showed a significant main effect of age for the driving-performance parameters. Also, compared to the baseline, texting WhatsApp messages while driving worsens driving performance for all age groups, most notably among older participants. Thus, the older drivers' SDLP was ∼14% higher than that for the baseline average of all the other drivers and rose to 29% under distraction, reflecting the impact of secondary tasks. The negative effect of the use of the smartphone during driving was also reflected in the number of collisions, with a greater risk of accidents in all the groups of drivers (by 8.3% for young adults, 25.0% for adults, 80.5% for middle-aged adults, and 134.5% for older drivers). Lastly, participants' subjective responses indicated that younger drivers (18-24 years) had a higher risk of deliberately violating safe driving practices (p < 0.05). The present study demonstrates that texting WhatsApp messages while driving significantly impairs the ability to drive safely, with older drivers being the group most adversely affected. It would be recommendable to include other nonstandard vision tests, which have shown associations with driving performance, in the examination for driver licensing. This would help raise the awareness of older drivers concerning their visual limitations, permitting them to adopt compensatory measures to improve their driving safety. Nevertheless, it is also necessary to raise awareness among the younger drivers of the risks involved in behaviour behind the wheel.

Impact of Dry Eye Disease on Vision Quality: An Optical Quality Analysis System Study

Purpose

We evaluated the relationship between ocular surface clinical tests and quality of vision in patients with dry eye disease (DED).

Methods

In this study, 136 eyes of 72 dry eye patients were evaluated retrospectively using the ocular surface disease index (OSDI), measurement of tear film break-up time (TBUT), the Oxford score, Van Bijsterveld score, and Schirmer I test. Quality of vision was assessed with the optical quality analysis system (OQAS) using the objective scatter index (OSI) recorded over 20 seconds without blinking. Correlations between dry eye symptoms and signs, and OSI measurements were evaluated.

Results

The OSI and OSI standard deviation (OSI SD) were correlated with TBUT (r = -0.21, P = 0.013 and r = -0.18, P = 0.038, respectively), Oxford score (r = 0.31, P = 0.0002 and r = 0.18, P = 0.032, respectively), and the Van Bijsterveld score (r = 0.33, P = 0.0001 and r = 0.25, P = 0.003, respectively). The OSI also was correlated with the Schirmer test (r = -0.19, P = 0.025), OSDI (r = 0.17, P = 0.04), and the ocular symptoms subscale of the OSDI (r = 0.21, P = 0.01). OSI SD was correlated with the environmental triggers subscale of the OSDI (r = 0.21, P = 0.016).

Conclusions

Quality of vision measured with the OQAS was correlated with dry eye symptoms and signs. The OQAS could be a useful tool to better evaluate visual function in patients with DED.

Translational Relevance

The OQAS provides a better understanding of patient complaints about alteration of vision quality. It might be useful to integrate this objective system in severity assessments and follow-up of DED, especially for treatment evaluations.