Optical quality in vitro and in vivo of an extended depth-of-focus intraocular lens with isofocal design.

PURPOSE: The aim of this study is to compare optical quality results obtained in laboratory analysis (in vitro) versus clinical data (in vivo). METHODS: The optical quality of ISOPure intraocular lens was assessed both in vitro and in vivo using the modulation transfer function (MTF) for 3.0 and 4.5 mm pupil diameters. In vitro measurements were obtained using deflectometer NIMO TRF1504, while in vivo measurements were taken with OPD-Scan III in a set of patients implanted with this lens. Ray tracing techniques were used to determine the MTF and area under MTF curve (MTFa) from the measured wavefront for the isolated lens and for the whole eye. RESULTS: The MTF of the isolated lens obtained under both in vitro and in vivo conditions showed comparable results for both pupil sizes. However, differences were found when comparing the MTF of the whole eye with the lens implanted versus the MTF measured in vitro for 4.5 mm pupil size. Also, the MTFa defocus curve was compared with the defocus curve measured in vivo. CONCLUSION: The defocus curve from the in vivo study aligns closely with the MTFa of the in vitro model, with a useful defocus range of 0.40D. Thus, it is possible to anticipate the visual results of the implanted isofocal lens by using measurements on an optical bench and conducting optical simulations.

Effect of decentration and tilt on the in vitro optical quality of monofocal and trifocal intraocular lenses.

PURPOSE: To evaluate and compare the effect of decentration and tilt on the optical quality of monofocal and trifocal intraocular lenses (IOL). METHODS: Optical quality of a monofocal IOL (AcrySof IQ SN60WF; Alcon Laboratories, Inc., USA) and a trifocal IOL (AcrySof IQ PanOptix; Alcon Laboratories, Inc., USA) was assessed using an in vitro optical bench (OptiSpheric IOL R&D; Trioptics GmbH, Germany). At apertures of 3.0 mm and 4.5 mm, modulation transfer function (MTF) at spatial frequency of 50 lp/mm, MTF curve and the United States Air Force (USAF) resolution test chart of the two IOLs were measured and compared at their focus with different degrees of decentration and tilt. Optical quality at infinity, 60 cm and 40 cm and the through-focus MTF curves were compared when the two IOLs were centered at apertures of 3.0 mm and 4.5 mm. Spectral transmittance of the two IOLs was measured by the UV-visible spectrophotometer (UV 3300 PC; MAPADA, China). RESULTS: The SN60WF and the PanOptix filtered blue light from 400 to 500 nm. Both IOLs at the far focus and the PanOptix at the intermediate focus showed a decrease in optical quality with increasing decentration and tilt. The PanOptix demonstrated enhanced optical quality compared to the previous gradient at the near focus at a decentration range of 0.3-0.7 mm with a 3.0 mm aperture, and 0.5 mm with a 4.5 mm aperture, whereas other conditions exhibited diminished optical quality with increasing decentration and tilt at the focus of both IOLs. When the two IOLs were centered, the SN60WF had better optical quality at infinity, while the PanOptix had better optical quality at 60 cm and 40 cm defocus. The optical quality of the SN60WF exceeded that of the PanOptix at far focus, with a 3 mm aperture decentration up to 0.7 mm and a 4.5 mm aperture decentration up to 0.3 mm; this observation held true for all tilts, irrespective of aperture size. As both decentration and tilt increased, the optical quality of the SN60WF deteriorated more rapidly than that of the PanOptix at the far focal point. CONCLUSIONS: The SN60WF showed a decrease in optical quality with increasing decentration and tilt. Optical quality of the PanOptix at the near focus increased in some decentration conditions and decreased in some conditions, while it showed a decrease at the other focuses with increasing decentration. While tilt only had a negative effect on optical quality. When both IOLs were centered, the PanOptix provided a wider range of vision, while the SN60WF provided better far distance vision. At the far focus, the SN60WF has better resistance to tilt than the PanOptix, but the optical quality degrades more quickly when decentered and tilted.

Optical power profiles and aberrations of a non-diffractive wavefront-shaping extended depth of focus intraocular lens.

PURPOSE: This study is to evaluate the optical characteristics of a non-diffractive wavefront-shaping intraocular lens which incorporates surface refractive modifications for shaping the wavefront in order to achieve extended depth of focus (EDoF) and to assess whether the nominal power of this IOL influences the attainable add power. METHODS: A commercially available optical bench NIMO TR1504 device (LAMBDA-X, Nivelles, Belgium) was employed to obtain full optical characterization of three non-diffractive EDoF intraocular lenses with + 10 D, + 20 D, and + 30 D powers. After NIMO measurements, data were computed using a custom-made MATLAB program (Mathworks, Inc., Natick, MA, USA) to evaluate the optical quality functions, such as the point spread function (PSF), wavefront profiles, and modulation transfer function (MTF) for two pupil sizes: 3 mm and 4.0 mm. RESULTS: The non-diffractive EDoF intraocular lens showed a central serrated power profile behavior with additions of + 2.00 to + 2.50 D over the nominal power. Higher order aberrations were found to be driven mainly by the spherical aberration, with almost null comatic influence. Optical quality metrics showed good values, better for a 3 mm pupil compared to a 4.5 mm one, as expected. The three IOL powers tested showed a very similar behavior in terms of power and aberrometric profiles, with minimal to null differences related to the nominal power. CONCLUSION: The non-diffractive wavefront-shaping EDoF intraocular lens achieves a near addition up to + 2.50 D aiming for an extended range of vision, almost independently of the base power.

Tolerance to decentration of biaspheric intraocular lenses with refractive phase-ring extended depth of focus and diffractive trifocal designs.

PURPOSE: This study aimed to investigate the in vitro tolerance to decentration of biaspheric intraocular lens (IOLs) with refractive phase-ring extended depth-of-focus (EDOF) and diffractive trifocal designs. METHODS: This experimental study was carried out at the Department of Optics and Optometry and Vision Science, University of Valencia, Spain. The modulation transfer function (MTF) of the ETLIO130C EDOF and the TFLIO130C trifocal IOLs (AST Products Inc., Billerica, MA, USA) were determined at different levels of decentration for a given wavelength and pupil diameter using the PMTF optical bench (Lambda-X Ophthalmics, Nivelles, Belgium). The modulation transfer function (MTF) curves, the through-focus MTF curves, and the Strehl ratios were measured at 3-mm pupil aperture for 0.25-, 0.50- and 0.75-mm decentration. RESULTS: The optical design of the trifocal TFLIO130C IOL is robust to small decentrations, with virtually no change in MTF response for 0.25 mm decentration. For greater decentration levels, the MTF response is slightly reduced with increasing decentration. The ETLIO130C EDOF design is robust to decentration, as the MTF response is only minimally affected when increasing the decentration up to 0.75 mm. CONCLUSIONS: MTF responses are slightly reduced with greater levels of decentration, but the range of focus provided by both trifocal and EDOF designs are preserved. The effects for average levels of decentration reported in the literature are minimum for both IOL designs.

Analysis of the optical performance of intraocular lenses using profilometric measurements.

PURPOSE: The aim of this study was to develop a methodology, based on profilometer measurements to assess the optical behaviour of Intraocular Lenses (IOls). The "Modulation Transfer Function through-object" (MTF through-object) based on vergence object displacement was calculated for different pupil sizes and pseudophakic eyes. Tilt and decentration were also analysed in a realistic cornea eye model. METHODS: For comparison between the different IOLs, an optical quality criterion based on a minimum value the MTF through-object and the recognition of simulated vision optotypes was introduced. Five IOLs were used in this study: Tecnis Eyhance, Mini Well, Tecnis Symfony, Tecnis Synergy and RayOne EMV. RESULTS: The technique was validated with previous methodologies. A general narrowing of the through-object MTF curve compared to the through-focus MTF curve was shown, resulting in greater distances between near and intermediate points and less depth of field around the far peak. The comparison between the IOLs showed that variations in corneal aberrations, pupil size and decentration caused relevant changes in IOL performance. A decrease of the SA produced a hypermetropic shift of the far focus between + 0.3 D and + 0.4 D. Most of IOLs worsen the optical quality as pupil size increased, even the MTF through-object shape changed. Decentration was an important factor in IOL implantation, causing a significant change in MTF through-object shape in most of IOLs. CONCLUSIONS: This study highlights the need to evaluate pre-operative patients for corneal aberrations and pupillary size to have the best optical success after cataract surgery in multifocal or extended depth of focus IOLs. KEY MESSAGES: What is known MTF(Modulation Transfer Function) through-focus curves (calculated in image space by moving the detector plane) can be obtained from optical bench assembly or from commercial devices. Recently, some studies proposed to characterize the lens surface design based on the profilometric measurements What is new A novel methodology based on profilometer measurements to assess the optical behaviour of Intraocular Lenses (IOls) was shown. The "Modulation Transfer Function through-object" based on vergence object displacement was introduced in order to analyse five premium IOLs. MTF through-object curve is more appropriate for studying clinical behaviour, as it provides further near and intermediate points distances and lower depth of focus around far peak compare to MTF through-focus curves. The optical behaviour of the five IOLs can vary considerably depending on the eye model and pupil size. The effect of tilt and decentration on the MTF through-object the IOLs was analysed.

Compound electrolyte intraocular irrigating solution produces better effects on vision recovery of cataract patients after surgery than Ringer lactate solution.

PURPOSE: Intraocular irrigating solution is extensively applied in cataract surgery. This paper explored the difference and relationship between optical coherence tomography (OCT) and optical quality analysis system (OQAS) parameters induced by compound electrolyte intraocular irrigating solution (CEIIS) or Ringer lactate (RL) solution during uncomplicated cataract surgery. METHODS: Totally 200 senior cataract patients were randomly divided into the CEIIS and RL groups (N = 100 patients/group). The anterior chamber was irrigated by CEIIS or RL during phacoemulsification. Patients were subdivided into diabetes mellitus (DM)+ and DM- groups. The central macular thickness (CMT), hyper reflective foci (HF), modulation transfer function cutoff frequency (MTF cutoff), Strehl ratio (SR), objective scatter index (OSI), and OQAS values (OVs) at 100%, 20%, and 9% contrast levels were measured preoperatively and 1 day and 1 week after operation using spectral-domain optical coherence tomography and OQAS II, respectively. Best-corrected visual acuity (BCVA) was assessed using the Snellen scale, followed by statistical analysis of its logarithm of the minimal angle of resolution. RESULTS: There were no significant differences in clinical characteristics between the CEIIS and RL groups. Both groups exhibited notably increased postoperative CMT, MTF cutoff, SR, OV at 100%, 20%, and 9% contrast levels, and reduced OSI, indicating CEIIS and RL improved postoperative visual quality. CEIIS surpassed RL solution in improving postoperative visual quality, decelerating the increase of macular HF numbers and CMT in DM+ patients and postoperative BCVA. There was no difference between CEIIS and RL in long-term vision improvement. CONCLUSION: CEIIS surpasses RL in postoperative visual recovery and retards increases of macular HF numbers and CMT in senior DM+ cataract patients.

Intense pulsed-light treatment improves objective optical quality in patients with meibomian gland dysfunction.

BACKGROUND: To evaluate changes in objective optical quality following intense pulsed light (IPL) treatment combined with meibomian gland (MG) expression (MGX) in patients with MG dysfunction (MGD). METHODS: This retrospective cross-sectional study included MGD-related dry eye disease (DED) patients who received IPL treatment between March and December 2021 at Kim's Eye Hospital, Seoul, Republic of Korea. Each patient underwent four sessions of IPL treatment using Lumenis M22 (Lumenis Ltd., Yokneam, Israel) and MGX at three-week intervals. RESULTS: This study included 90 eyes from 45 patients with MGD. The mean age was 52.3 ± 16.1 years (range, 20-75 years), and 53.3% (24/45) of patients were female. Compared with the baseline, all clinical symptoms and signs significantly improved after IPL treatment combined with MGX. All optical quality parameters obtained with an optical quality analysis system (OQAS: Visiometrics, Castelldefels, Spain) have improved significantly over the baseline (p < 0.001). CONCLUSIONS: In patients with MGD, IPL treatment combined with MGX improved the objective optical quality and clinical signs and symptoms of DED.

Changes in visual function and optical and tear film quality in computer users.

PURPOSE: To assess changes in visual function and optical and tear film quality in computer users. METHODS: Forty computer workers and 40 controls were evaluated at the beginning and end of a working day. Symptoms were assessed using the Quality of Vision questionnaire (QoV), 5-item Dry Eye Questionnaire (DEQ-5) and Symptom Assessment in Dry Eye version II (SANDE II). Tear film quality was evaluated using the Medmont E300 dynamic corneal topography tool to measure the tear film surface quality (TFSQ), TFSQ area and auto tear break-up time (TBUT). Optical quality was assessed by measuring high, low and total ocular aberrations with a Hartmann-Shack wavefront sensor. Visual performance was assessed by measuring photopic and mesopic visual acuity, photopic and mesopic contrast sensitivity and light disturbance. RESULTS: Poorer DEQ-5, QoV and SANDE II scores were obtained in computer workers at the end of the working day compared with controls (p ≤ 0.02). Computer workers exhibited a higher (worse) TFSQ and TFSQ area at visit 2 compared with visit 1 (p ≤ 0.04), while no significant differences in TBUT (p = 0.19) or ocular aberrations were observed (p ≥ 0.09). Additionally, both light disturbance (p ≤ 0.04) and mesopic and photopic contrast sensitivity worsened at several spatial frequencies (p ≤ 0.04) throughout the working day in computer workers, while visual acuity remained unchanged (p ≥ 0.07). In contrast, control subjects exhibited no decrease in any variable during the day. CONCLUSIONS: While visual acuity remained unchanged, several aspects of visual function and quality of vision decreased over a day of computer use. These changes were accompanied by greater dry eye symptoms and tear film changes, which are likely to have played a fundamental role. The present study provides insight into new metrics to assess digital eye strain.

Assessment of optical quality of ready-made reading spectacles for presbyopic correction.

PURPOSE: Many presbyopic patients in both developed and developing countries use ready-made reading spectacles for their near vision correction even though the quality of these spectacles cannot always be assured. This study assessed the optical quality of ready-made reading spectacles for presbyopic correction in comparison with relevant international standards. METHODS: A total of 105 ready-made reading spectacles with powers ranging from +1.50 to +3.50 dioptres (D) in +0.50 D steps were randomly procured from open markets in Ghana and assessed for their optical quality, including induced prisms and safety markings. These assessments were done in line with the International Organization for Standardization (ISO 16034:2002 [BS EN 14139:2010]) as well as the standards used in low-resource countries. RESULTS: All lenses (100%) had significant induced horizontal prism that exceeded the tolerance levels stipulated by the ISO standards, while 30% had vertical prism greater than the specified tolerances. The highest prevalence of induced vertical prism was seen in the +2.50 and +3.50 D lenses (48% and 43%, respectively). When compared with less conservative standards, as suggested for use in low-resource countries, the prevalence of induced horizontal and vertical prism reduced to 88% and 14%, respectively. While only 15% of spectacles had a labelled centration distance, none had any safety markings per the ISO standards. CONCLUSION: The high prevalence of ready-made reading spectacles in Ghana that fail to meet optical quality standards indicates the need for more robust, rigorous and standardised protocols for assessing their optical quality before they are sold on the market. This will alleviate unwanted side effects including asthenopia associated with their use. There is also the need to intensify public health awareness on the use of ready-made reading spectacles, especially by patients with significant refractive errors and ocular pathologies.

Optical Quality Variation of Different Intraocular Lens Designs in a Model Eye: Lens Placed Correctly and in an Upside-Down Position.

INTRODUCTION: Intraocular lenses (IOLs) may lose their optical quality if they are not correctly placed inside the capsular bag once implanted. One possible malpositioning of the IOL could be the implantation in an upside-down position. In this work, three aspheric IOLs with different spherical aberration (SA) have been designed and numerically tested to analyse the optical quality variation with the IOL flip, and misalignments, using a theoretical model eye. METHODS: Using the commercial optical design software OSLO, the effect of decentration and tilt was evaluated by numerical ray tracing in two conditions: in their designed position and flipped with respect to the planned position (IOL is implanted upside down). The theoretical model eye used was the Atchison model eye. Seven IOL designs of +27.00 diopters were used: a lens with negative SA to correct the corneal SA, a lens to partially correct the corneal SA, and a lens to not add any SA to the cornea (aberration-free IOL). These lenses were designed with the aspherical surface located on the anterior and posterior IOL surface. A lens with no aspherical surfaces was also included. For the optical quality analysis, the modulation transfer function (MTF) was used, together with the Zernike wavefront aberration coefficients of defocus, astigmatism, and primary coma. RESULTS: Off-centring and tilting the IOL reduced overall MTF values and increased wavefront aberration errors. With the IOL correctly positioned within the capsular bag, an aberration-free IOL is the best choice for maintaining optical quality. When the IOL is flipped inside the capsular bag, the optical quality changes, with the aberration-free IOL and the IOL without aspheric surfaces providing the worst results. With the lens in an upside-down position, an IOL design to partially correct corneal SA shows the best optical quality results in decentration and tilt, in terms of MTF and wavefront aberrations. CONCLUSION: The aberration-free IOL is the best choice when minimal postoperative errors of decentration or tilt are predicted. With IOL flip, the negative SA lens design is the best choice, regarding the root mean square wavefront aberrations. However, in a proper IOL implantation, the IOL designed to partially compensate the corneal SA including asphericity on its posterior surface is the better possible option, even in the presence of decentration or tilt.

Subjective patient-reported visual quality after small-incision lenticule extraction and its correlation to the objective one.

PURPOSE: The purpose of the study was to characterize the subjective visual quality and satisfaction following small-incision lenticule extraction (SMILE) and to identify its influential factors. SETTING: Peking University Third Hospital, Beijing, China. DESIGN: This was a retrospective observational study. METHODS: Patients who had simultaneous binocular SMILE for myopia and myopic astigmatism were included 6 months postoperatively, and the patient-reported outcome questionnaire was employed for the assessment of visual quality in real-life situations. Examinations with SIRIUS combined corneal topography and tomography were performed including the parameters of Strehl ratio (SR), corneal higher-order aberrations (HOAs) within 6.0-mm area, kappa angel, and thinnest corneal thickness. Decentration and effective optical zone (EOZ) were measured based on a tangential pre-post-operation difference map. Binary logistic regression analysis was performed for predictors of patient-reported visual quality. RESULTS: Clinical data from 97 cases were analyzed retrospectively. Overall satisfaction was 96.91% (94/97). Fluctuation in vision and glare is the most frequent and dominant visual symptoms. SR value increased non-significantly compared with preoperative (P> 0.05). A statistically significant (P < 0.05) increase in total HOAs, spherical aberration, and coma was noted. SR and HOAs were not correlated with the degree of visual symptoms (P > 0.05). No objective parameter was found to be associated with patient-reported visual quality after SMILE (P> 0.05). CONCLUSION: The high patient-reported satisfaction confirmed the ideal effect on visual quality following SMILE in real-life situations, though some objective optical performances were not satisfying. It is very tolerant toward patients' conditions and mild deviations, and this study did not find factors affecting visual performances.

Femtosecond laser-assisted cataract surgery versus conventional phacoemulsification: comparison of internal aberrations and visual quality.

PURPOSE: To compare the internal aberrations and optical quality after femtosecond laser-assisted cataract surgery (FLACS) and conventional phacoemulsification cataract surgery (CPCS). METHODS: This study included patients who received FLACS or CPCS from January 2016 to July 2019. Postoperative examinations included wavefront measurements under pupil diameters of 3.0 mm and 5.0 mm, intraocular lens (IOL) decentration, visual acuity (VA), and refractive outcomes. Visual quality was measured with Strehl ratio and modulation transfer function (MTF). Subgroup analyses were conducted based on monofocal or multifocal-extended depth of focus (EDOF) IOL. RESULTS: The study consisted of 221 eyes (105 eyes in FLACS and 116 eyes in CPCS). With a pupil diameter of 5.0 mm, FLACS demonstrated a significantly lower root mean square of total internal aberration (P = 0.004), higher order aberrations (HOAs) (P = 0.034), tilt (P = 0.049), coma (P = 0.004), and spherical aberration (P = 0.014). IOL tilt was found to be positively correlated with total internal aberration (P < 0.001), HOAs (P < 0.001), and coma (P < 0.001). The FLACS group presented significantly smaller IOL decentration than the CPCS group (P < 0.001), but there were no significant differences in terms of VA and refractive outcomes between groups. In the multifocal-EDOF subgroup, Strehl ratio and MTF values were significantly higher in the femtosecond group with a 3.0-mm pupil. CONCLUSION: FLACS induced significantly lower values of IOL tilt, decentration, and internal aberrations compared with the CPCS group with a pupil diameter of 5.0 mm, while no significant differences were found in the VA or optical quality over long-term observation. TRIAL REGISTRATION: This trial was registered at www.chictr.org.cn (registration number ChiCTR2000038965).

Evaluating impact of Nd: YAG laser associated defects on optical quality of hydrophilic and hydrophobic intraocular lenses using visualization of light propagation and USAF test targets.

BACKGROUND: Neodymium:yttrium aluminum garnet (Nd:YAG) laser capsulotomy is a well-accepted, safe, and effective measure in the treatment of posterior capsule opacification. However, iatrogenic intraocular lens damage is a relatively common side effect that happens due to inappropriate focusing during the procedure. This experimental study analyzes the impact of YAG-pits to obtain qualitative information. METHODS: Acrylic, monofocal hydrophilic and hydrophobic intraocular lenses (IOLs) with 6.0 mm optic and the with the same power (21D) were studied. First, all measurements were done with unmodified IOLs. Damage was intentionally created, performing YAG-pits (n = 5) in the central area of the lens optic (3.0 mm) using a photodisruption laser with the same energy level of 1.8 mJ. To simulate the cruciate pattern, the 5 defects were created in a cross shape within the 3.0 mm optical zone. Afterwards, all laboratory measurements were repeated: These included the United States Air Force (USAF) resolution test chart to study the imaging performance of the IOL, light field measurements to show the course of the rays behind the IOL and the modulation transfer function (MTF) measurements were analyzed. RESULTS: Evaluating USAF showed that unmodified lenses produced a sharper image. Damaged lenses led to a more blurred image and to the impression of a lower contrast with a kind of halo/glare effect. The light field measurement showed that YAG-pits led to a kind of dispersion and scattering effect, which was higher in hydrophobic IOLs. MTF showed a deterioration in damaged hydrophilic and hydrophobic IOLs, respectively. CONCLUSION: Our experimental study confirms that YAG-pits can reduce imaging quality of intraocular lenses. These defects behave as a new Huygens source, distribute a spherical wave that additionally illuminate the background of the USAF target. It can be assumed that material properties of the IOL (water content, refractive index) play an important role and affect results. The impact level is strongly dependent on the number, size and position of YAG-pits within the optic. LIMITATION: Only monofocal IOLs have been investigated so far, further tests with various IOL optics have to follow. In addition, simulating the circular pattern of YAG capsulotomy is necessary.

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 a variation in optical quality parameters measured using the HD Analyzer™ between preoperative and 2-month postoperative 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 postoperative 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 preoperative assessment of primary ERM and other pre-vitrectomy assessments.

Quality control of rigid endoscopes: a comparative study between ScopeControl® and surgeons' evaluation.

BACKGROUND: In central sterile services departments (CSSD), the functionality of rigid endoscopes, which are complex and fragile reusable devices, is usually controlled visually and is considered a complex and subjective task. ScopeControl® was developed to provide an automated quality control of rigid endoscopes by measuring the value of six parameters: viewing angle (VA), field of view (FV), color correctness (CC), light transmission (LT), fibers transmission (FT), and focus (FC). The aim of the present study was to assess the ability of ScopeControl® to pre-emptively identify endoscope defects before the surgeon considers them as defective. METHODS: The same endoscope was evaluated by surgeons during surgery using a scoring scale as well as the CSSD staff using the ScopeControl® during reprocessing. The ScopeControl® categorized the endoscope into 3 groups: "passed," "in danger," and "failed." Correlations between the surgeon's evaluation and results of the ScopeControl® were calculated. RESULTS: One hundred sixty-six controls were carried out concerning 51 different endoscopes. According to the surgeon's evaluation, 78.9% and 80.7% of controls were considered as satisfactory for image and brightness quality, respectively. Results obtained using ScopeControl® found that 13.3% of controls were considered as "passed," 31.3% "in danger," and 55.4% "failed," with poor correlation with the surgeons' evaluation. LT and FT parameters represented 95.2% of the reasons for failures. The ability of the ScopeControl® to detect endoscope defects earlier than surgeons was validated by tracking the results of endoscopes used and controlled several times. CONCLUSION: The ScopeControl® achieved an objective and consistent quality control of endoscopes and showed poor correlation with the surgeon's opinion. In practice, the ScopeControl® could avoid the use of defective endoscopes in the surgery unit and thus improve the quality of the surgical procedure.

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.

Agreement between subjective and predicted high and low contrast visual acuities with a double-pass system.

PURPOSE: To evaluate the agreement between subjective high and low contrast visual acuity (VA) and predicted values from double-pass system measurements in healthy candidates to laser refractive surgery. METHODS: Ninety-two eyes measured during the preoperative screening to laser refractive surgery were included in this retrospective analysis. High contrast subjective visual acuity (HCVA) and low contrasts at 20% (LCVA20) and 9% (LCVA9) were compared with the predicted VA obtained with a commercial double-pass system (OQAS) at the same levels of contrast, 100% (OV100), 20% (OV20), and 9% (OV9). The agreement was evaluated with Bland-Altman analysis computing the limits of agreement (LoAs) and the correlations with the spearman rho. RESULTS: An underestimation of VA was obtained with the double-pass system for the highest contrast. Differences between predictive and subjective measurements were statistically significant for 100% contrast (- 0.08 logMAR, p < 0.0005), but not for 20% (- 0.03 logMAR, p = 0.07) and 9% (- 0.02 logMAR, p = 0.9) of contrasts. The LoAs increased with the decrease of contrast from 0.29 with 100% to 0.39 logMAR with 9% of contrast. A weak correlation was obtained between subjective and predicted VA (rho ≤ 0.33) that was only significant for 100% (p = 0.001) and 20% (p = 0.004) contrasts. CONCLUSION: Mean differences between methods were reasonably small so mean results obtained for predicted VA in OQAS studies can be considered as reliable, at least in healthy subjects and for low contrast. However, limits of agreement were considerably poor which means that OQAS cannot replace individual subjective measurements of VA in clinical practice.

Evaluation of optical quality in pterygium patients with a new modified sutureless and glue-free method.

BACKGROUND: Modified sutureless and glue-free method is an effective and novel surgical approach for pterygium. We aim to evaluate optical quality in pterygium treated with the new method and investigate the clinical application of the Optical Quality Analysis System (OQAS) and Anterior segment optical coherence tomography (AS-OCT) to evaluate the pterygium surgery. METHODS: A total of 52 eyes of 52 patients with pterygium were randomly divided into 2 groups. After surgical excision, the bare sclera was placed with a tight fit limbal conjunctival autograft fixed via the modified sutureless and glue-free method in group 1 (26 eyes) and conventional sutures in group 2 (26 eyes). Objective scattering index (OSI), modulation transfer function (MTF) and Strehl ratio (SR) were measured using OQAS in both groups during the perioperative period. Pterygium diameter was measured on AS-OCT. Ocular surface disease index (OSDI) questionnaire also was used. RESULTS: The group 1 had significantly lower mean OSI, higher mean MTF, and higher mean SR at 1 month and 3 months after surgery (p < 0.05). The group 1 had significantly lower mean OSDI at 1 month (p < 0.05), while was similar to group 2 at 3 months (p > 0.05). Pterygium diameter positively correlated with OSI (r = 0.528, p < 0.001), while it negatively correlated with MTF (r = - 0.501, p < 0.001) and SR (r = - 0.174, p = 0.217) before operation. CONCLUSIONS: The modified sutureless and glue-free method might be more advantageous in improving the optical quality during early postoperative recovery times and pterygium diameter affected optical quality. OQAS can be reliably used to evaluate postoperative outcomes.

Comparison of the optical quality after SMILE and FS-LASIK for high myopia by OQAS and iTrace analyzer: a one-year retrospective study.

BACKGROUND: To compare the correction effect and optical quality after small-incision lenticule extraction (SMILE) and femtosecond laser assisted laser in situ keratomileusis (FS-LASIK) for high myopia. METHODS: 51 high myopia eyes after SMILE and 49 high myopia eyes after FS-LASIK were enrolled and divided into two groups retrospectively. The OQAS and iTrace analyzer were used for optical quality inspection. Between the two groups the spherical equivalent (SE), astigmatism, uncorrected distant visual acuity (UDVA), strehl ratio (SR), modulation transfer function cutoff frequency (MTF cutoff), objective scatter index (OSI) and wavefront aberrations were analyzed and compared before surgery and at 1, 6 and 12 months after surgery. RESULTS: After the operation: (1) SE and astigmatism declined and UDVA increased significantly in both groups, and UDVA was better after SMILE than FS-LASIK. (2) SR and MTF cutoff reduced and OSI increased significantly after SMILE and FS-LASIK. SR and MTF cutoff were significantly higher after SMILE than FS-LASIK. OSI was significantly lower after SMILE than FS-LASIK. (3) The total wavefront aberration, total low-order wavefront aberration, defocus and astigmatism aberration as well as trefoil aberration reduced significantly in both groups. The total high-order wavefront aberration increased significantly after FS-LASIK. The spherical and coma aberration increased significantly in both groups. The total high-order wavefront aberration and coma aberration at 1 month were higher after FS-LASIK than SMILE. CONCLUSION: The optical quality descended after SMILE and FS-LASIK. SMILE was superior to FS-LASIK at the correction effect and optical quality for high myopia. The combination of OQAS and iTrace analyzer is a valuable complementary measurement in evaluating the optical quality after the refractive surgery. TRIAL REGISTRATION: This is a retrospective study. This research was approved by the ethics committee of Xiangya Hospital and the IRB approval number is 201612074.

Laboratory analysis and ray visualization of diffractive optics with enhanced intermediate vision.

BACKGROUND: To assess the optical behavior of a new diffractive intraocular lens (IOL) and compare its performance to that of an established extended-depth-of-focus (EDOF) IOL. METHODS: This study assessed the Proming EDOF Multifocal AM2UX [Eyebright Medical Technology (Beijing) Co., Ltd., China] and the AT LARA 829MP [Carl Zeiss Meditec, Germany]. An experimental set-up with 0.01% fluorescein solution and monochromatic light (532 nm) was used to visualize the IOLs' ray propagation. In addition, the optical quality of the IOLs was assessed by measuring the modulation transfer function (MTF) values at 50lp/mm and 3.0 and 4.5 mm apertures on the optical bench OptiSpheric® IOL PRO II [Trioptics GmbH, Germany]. RESULTS: The ray propagation of the two IOLs showed two distinct foci. Light intensity assessment revealed that both IOLs allocate more energy to primary than secondary focus. At 3.0 mm pupil, the MTF values at 50lp/mm for the primary focus were 0.39 and 0.37, and for the secondary focus, 0.29 and 0.26 for the AT LARA and Proming IOLs, respectively. At 4.5 mm pupil, the single-frequency MTF for the primary focus was 0.51 and 0.24 and for the secondary focus 0.21 and 0.15 for the AT LARA and Proming IOLs, respectively. CONCLUSIONS: When tested with an aberration-free model cornea under monochromatic conditions, the Proming behaved as a low-add bifocal lens; however, its properties did not differ much from the well-established AT LARA EDOF IOL. The AT LARA outperformed the Proming at low defocus (up to 2D), while the latter demonstrated better image quality in the 2-3D range.