Clinical safety and efficacy of elliptical thin-flap LASIK using a low-pulse energy femtosecond laser.

This study assessed the clinical safety and efficacy of elliptical thin-flap LASIK with a low-pulse energy femtosecond laser in 3 thickness subgroups (85, 90, and 100 µm). A total of 80 patients who underwent bilateral LASIK surgery at Taiwan between April and September 2019 were retrospectively enrolled. Elliptical corneal flaps with wide temporal hinges and inverted-angled side cuts were created. Target flap thickness was calculated on the basis of residual stromal bed thickness and percent tissue altered. Before flap creation, an optical coherence tomography image for visualization of the precut flap position was obtained with the built-in camera. At postoperative month 1, the overall mean logMAR uncorrected distance visual acuity (UDVA) was - 0.04 ± 0.07 (20/18 Snellen), with 96% of eyes achieving UDVA of 20/20 or better. Postoperative mean manifest spherical equivalent was - 0.37 ± 0.42 D at 1 month. The visual and refractive outcomes in each of the 3 subgroups were similar. The achieved flap thicknesses were found to be highly predictable and consistent in the respective thickness subgroups. Optical coherence tomography-guided thin-flap LASIK performed with the low-pulse energy femtosecond laser was found to be safe with no intraoperative or postoperative complications.

Comparing clinical outcomes of Optiwave Refractive Analysis, Lenstar, and surgeon's modified method for intraocular lens power calculation in Asian eyes.

The study aimed to compare the accuracy of intraocular lens (IOL) calculation to predict postoperative refraction by Optiwave Refractive Analysis (ORA), Lenstar LS 900, and the surgeon's Modify method in normal Asian eyes. The IOL power of the Lenstar group was calculated according to Lenstar LS 900, whereas the surgeon's Modify group used topography, axial length (AL) of Lenstar, and Barrett Universal II online formula. Intraoperative aphakic measurements and IOL power calculations were obtained with the ORA system. From the results acquired through Lenstar, Modify, and ORA, the surgeon used his judgment to select the actual IOL power. Postoperative manifest refraction spherical equivalent (MRSE) was obtained 2 months after surgery. The prediction error (PE) was calculated as the difference between the postoperative MRSE and the target refraction proposed by three methods. AL, anterior chamber depth (ACD, measured from corneal endothelium to lens), lens thickness (LT), and ACD + 1/2LT were also included in the survey. In 67 eyes, the average real PE was smaller for the Lenstar (0.06 ± 0.44) and Modify (- 0.05 ± 0.40) than for the ORA group (- 0.25 ± 0.60, p < 0.05). The ORA system demonstrated the best results of IOL power selection in eyes with a normal range of ACD + 0.5 LT (5.2-5.6 mm) in Asian eyes.

Effectiveness of reducing corneal astigmatism after combined high-frequency LDV Z8 femtosecond laser-assisted phacoemulsification and arcuate keratotomy.

Purpose: In this retrospective study, the efficacy of the FEMTO LDV Z8 Femtosecond Laser-Assisted Cataract Surgery (Femto Z8 FLACS) and the Femtosecond laser Arcuate Keratotomy (FSAK) in decreasing the corneal astigmatism was investigated. Methods: During FLACS, FSAK was positioned with the help of the FEMTO LDV Z8 laser at a diameter of 8.5 mm and an 80% depth. Before and 3 months after surgery, the astigmatism of the cornea was measured with the aid of Pentacam. The variables influencing the efficacy of FSAK were assessed using the multiple regression analysis technique. Vector analyses were carried out. To determine the net corneal alterations, the with-the-wound and against-the-wound variations were computed along the FSAKs' meridian. Results: This study investigated 80 eyes from 62 participants. The average keratometric astigmatism value was 0.92 ± 0.44 diopters (D). The average keratometric astigmatism decreased to 0.61 ± 0.45 D 3 months following FSAK compared to preoperative corneal astigmatism (p < 0.05). Additionally, there was a considerable decline in the percentage of eyes with ±0.5 D and ±1.0 D astigmatism, which reduced 3 months after surgery by 58% and 85%, respectively (p < 0.05). Conclusion: The FEMTO LDV Z8 laser can create an effective and precise arcuate keratotomy with an excellent safety profile, rapid recovery, and vision stability.

Difference in Quality of Vision Outcome among Extended Depth of Focus, Bifocal, and Monofocal Intraocular Lens Implantation.

We aimed to compare the postoperative quality of vision among patients who received extended depth of focus (EDOF), bifocal, and monofocal intraocular lens (IOL) implantation. A retrospective study was conducted, and 87 patients who underwent cataract surgery were enrolled. Patients were categorized into different groups according to IOL design, with 24, 29, and 34 individuals constituting bifocal, EDOF, and monofocal groups. Preoperative and postoperative visual acuity (VA), biometry data, refractive status, contrast sensitivity (CS), higher-order aberrations (HOAs), and a quality of vision questionnaire that consisted of 11 questions were obtained 1 month postoperatively. The Kruskal−Wallis test and Pearson's chi-square test were applied for statistical analyses. The postoperative CDVA was better in the EDOF group than in the bifocal group (p = 0.043), and the residual cylinder was lower in the EDOF groups than in the other two groups (both p < 0.05). The CS was worse in the EDOF group than in the other two groups (all p < 0.05), while the spherical aberration and trefoil were lower in the EDOF group than in the bifocal group (both p < 0.05). In terms of the quality of vision, the scores were better in the monofocal group than in the EDOF group in seven items (all p < 0.05), and the quality of vision in the bifocal group was better than in the EDOF group in small print reading (p = 0.042). In addition, the incidence of glare was lower in the monofocal group than in the other two groups (p < 0.001), while the spectacle dependence ratio was significantly higher in the monofocal group compared to the other two groups (p < 0.001). In conclusion, the general quality of vision was better in the monofocal group compared to the bifocal and EDOF groups, while the spectacle dependence ratio was significantly higher in the monofocal group than in the other two groups.

Comparison of cumulative dispersed energy between conventional phacoemulsification and femtosecond laser-assisted cataract surgery with two different lens fragmentation patterns.

The purpose of the study is to compare the total ultrasound power used between eyes undergoing different lens fragmentation patterns of femtosecond laser-assisted cataract surgery (FLACS) and conventional phacoemulsification surgery (CPS). A total of 506 patient eyes underwent preoperative grading of lens opacity using the Lens Opacity Classification System III (LOCSIII). The eyes were divided into two subgroups: subgroup 1 had a LOCSIII grade of 1-3, and subgroup 2 had a LOCSIII grade of 4-6. The eyes underwent FLACS (LenSx) for clear corneal wound, capsulotomy, and lens fragmentation. Either a grid pattern or radial pattern was used for lens fragmentation. The eyes received one of the following three treatments: (1) CPS without femtosecond laser assistant, (2) FLACS with a grid pattern (FGP) lens fragment, or (3) FLACS with a quadrant pattern (FQP) lens fragment. The mean cumulative dispersed energy (CDE) for each subgroup and treatment was evaluated. The mean CDE was lower in the two FLACS groups (1.21±1.91 in FGP and 1.22±1.92 in FQP) than that in the CPG group (2.67±2.84). In subgroup 1, CDE was higher in the CPG group (1.54±1.18) as compared with the FLACS groups (0.16±0.31 in FGP and 0.74±1.17 in FQP; P<0.001). In subgroup 2, CDE was higher in the CPG (6.47±3.46) as compared with the FLACS groups (2.74±2.21 in FGP and 5.34±2.17 in FQP; P<0.001). CDE was lower in the two FLACS groups than that in the CPS group, and CDE was the lowest with FGP in both subgroups 1 and 2.

Surgical outcomes with high and low pulse energy femtosecond laser systems for cataract surgery.

Currently, there is no clear consensus in cataract surgery if low compared to high energy femto-lasers may enable better capsulotomy quality and induce lower inflammatory response. Therefore, the aim of this study was to compare the intra-operative outcomes achieved with high and low pulse energy femtosecond laser systems for cataract surgery. The charts of 200 eyes of 200 patients aged 68.3 ± 10.3 years who had undergone femtosecond laser-assisted cataract surgery using either group 1 high pulse energy: LenSx (Alcon Laboratories) (N = 100) or group 2 low pulse energy: FEMTO LDV Z8 (Ziemer) (N = 100) laser were reviewed retrospectively. Integrity of anterior capsulotomy, classified as (1) complete (free-floating or with minor microadhesions), (2) incomplete and (3) with capsular tears, intraoperative completeness of the clear corneal incisions (CCI, main incision and side port), incidences of intraoperative miosis and incidence of subconjunctival hemorrhage were evaluated and compared between the two groups. The proportion of complete capsulotomies was significantly higher in the group 2 than the group 1 (100% vs 94%; p = 0.03). The incidences of intraoperative miosis (0% vs 19%) and subconjunctival hemorrhage (1% vs 63%) were significantly lower in the group 2 than the group 1 (p < 0.001). Completeness of the main incision was comparable (97% vs 95%; p = 0.721) between the two groups. Although not statistically significant, the completeness of side-port incision was slightly better in the group 2 than the group 1 (91% vs 86%). Low energy laser system performed significantly better in terms of completeness of capsulotomy, intraoperative miosis and sub-conjunctival hemorrhage, compared with high energy laser; the CCI outcomes were comparable.

A Novel Sequential Docking Technique: Use of Femtosecond Arcuate Keratotomy and Femtosecond Assisted Cataract Surgery Using a Pupil Expansion Ring on a Patient with Intraoperative Floppy Iris Syndrome.

PURPOSE: The purpose of this study was to evaluate the efficacy of a novel double-docking technique, incorporating the use of femtosecond laser arcuate keratotomy (FSAK) in correcting low-degree astigmatism and Malyugin ring, in a patient with intraoperative floppy iris syndrome (IFIS). METHODS: A case report of a 72-year-old man with grade 4 cataract, low-degree astigmatism (<2D), and IFIS (pupil size <4 mm, intraoperatively) is presented. The patient underwent cataract surgery using a femtosecond laser to treat low-degree astigmatism because the patient requested for the use of a multifocal  intraocular lens (IOL). The first docking was performed to complete arcuate keratotomy, produce the mainparacentesis incisions, and create clear corneal incisions. Insertion of the Malyugin ring was performed after the first docking, whereas the second one was executed to complete continuous curvilinear capsulotomy and lens fragmentation. The patient's uncorrected visual acuity (UCVA) was measured pre- and post-operatively. The complications were evaluated post-operatively and 3 months later during the follow-up visit. RESULTS: The patient's UCVA for distance improved from 0.3 (6/12 Snellen equivalent) to 0 (6/6 Snellen equivalent) logMAR post-operatively. During the follow-up visit, the patient's uncorrected near visual acuity was at J2. His corneal astigmatism changed from -1.0 Diopter @177° pre-operative to -0.12 D @173° post-operative. No other intraoperative or post-operative complications were observed. CONCLUSION: The double-docking technique, with the use of FSAK, and Malyugin ring produced successful surgical outcomes for the patient. The benefits of this technique allow surgeons to avoid changing the shape of the patient's cornea from the injection of the viscoelastic device into the anterior chamber, which could lower the femtosecond laser's precision and docking location.

Chirped polarization volume grating with ultra-wide angular bandwidth and high efficiency for see-through near-eye displays.

We report a reflective chirped polarization volume grating (CPVG) with a dramatically wider angular bandwidth and significantly higher first-order diffraction efficiency than the holographic volume grating and surface relief grating for large field-of-view (FOV) augmented reality (AR) displays. By introducing gradient pitch structure along the beam propagation direction, the angular bandwidth is extended from 18° to 54° while keeping over 80% diffraction efficiency. We also prepare a two-layer reflective PVG and compare its performance with the chirped structure. Based on the simulation and experimental results, CPVG is a strong contender for large FOV AR displays.

Photo- and electrical-responsive liquid crystal smart dimmer for augmented reality displays.

A dual-stimuli polarizer-free dye-doped liquid crystal (LC) dimmer is demonstrated. The LC composition consists of photo-stable chiral agent, photosensitive azobenzene, and dichroic dye in a nematic host with positive dielectric anisotropy. Upon UV exposure, the LC directors and dye molecules turn from initially vertical alignment (high transmittance state) to twisted fingerprint structure (low transmittance state). The reversal process is accelerated by combining a longitudinal electric field to unwind the LC directors from twisted fingerprint to homeotropic state, and a red light to transform the cis azobenzene back to trans. This device can be used as a smart dimmer to enhance the ambient contrast ratio for augmented reality displays.

A novel minimal fluid technique for effective and safe lens hydrodissection during cataract surgery.

Traditional hydrodissection may cause posterior capsule rupture (PCR) if excessive fluid accumulates. In this study, we describe the successful application of a novel minimal fluid hydrodissection technique in 100 consecutive cataract surgery cases. This technique separates the nucleus from the capsule utilizing low hydrostatic pressure and precise kinetic movement of a small volume (around 0.2 cc) of balanced salt solution. There were no instances of PCR. This technique is suitable for a range of cases, including femtosecond laser-assisted cataract surgery and posterior subcapsular cataract.

Novel method for preventing cyclorotation in Ziemer Femto LDV Z8 femtosecond laser-assisted cataract surgery with Verion image-guided system.

PURPOSE: To investigate the feasibility of a new method involving the use of the Verion image-guided system in preventing cyclorotation during femtosecond laser-assisted cataract surgery (FLACS). PATIENTS: Our preliminary data included details of 24 consecutive patients. All patients underwent cataract surgery at Universal Eye Center, Zhong-Li, Taiwan, between December 2016 and January 2017. METHODS: We developed a technique to use the Verion image-guided system in FLACS and evaluated whether this new technique is compatible with Femto LDV Z8. The Verion image-guided system was used to prevent misalignments. The only additional step in this technique is using a marking tool to place ink on the corneal limbus (at 3 and 9 o'clock positions) guided by the Verion digital marker system. Remaining procedures could be performed using the touchscreen of Femto LDV Z8 to calibrate the horizontal reference axis. RESULTS: This study included 24 patients who underwent cataract surgery. The technique used could effectively neutralize misalignments at an average of 8.08° and 2.66° in clockwise and counterclockwise directions, respectively. CONCLUSION: This technique combines the advantages of iris fingerprinting technology and mobile features of Femto LDV Z8, has fewer transfer steps, improves centration of the eyes, and, most importantly, can prevent misalignments through cyclotorsion or docking procedures. Furthermore, this method can improve the accuracy of arcuate incisions and toric intraocular lens alignment in astigmatism correction.

Comparison of corneal power obtained from VERION image-guided surgery system and four other devices.

PURPOSE: To assess the corneal keratometric values obtained using the VERION image-guided surgery system and other devices. METHODS: This study evaluated the right eyes of 115 cataract patients before intraocular lens (IOL) implantation through consecutive tests using 5 devices: VERION Reference Unit, Placido-based corneal topography (OPD-Scan III), monochromatic light-emitting diodes (LenStar LS900 and AL-Scan), and rotary prism technology (auto kerato-refractometer KR-8800). Analyzed parameters were corneal steep and flat keratometric values (Ks and Kf) and corneal astigmatism and axis. These parameters were evaluated using the one-sample two-tailed t-test and the 95% limits of agreement (95% LOAs) between the devices. RESULTS: The mean corneal cylinder value measurements were -0.97±0.63 D, -0.88±0.60 D, -0.90±0.69 D, -0.90±0.67 D, and -0.83±0.60 D with VERION, LenStar, AL-Scan (2.4 mm), OPD III, and KR-8800, respectively. Only KR-8800 showed a significant difference from VERION in the corneal cylinder value (P<0.05). The mean differences in the Kf and Ks of VERION compared to those of OPD III were 0.18±0.45 D and 0.17±0.38 D (P<0.05), respectively. The 95% LOAs of Bland-Altman analysis for the corneal astigmatism axis of the VERION with LenStar, AL-Scan (2.4 mm), OPD III, and KR-8800 were -26.25° to 58.71°, -20.61° to 47.44°, -25.03° to 58.98°, and -27.85° to 65.17°, respectively. CONCLUSION: None of the VERION parameters were significantly different from those of AL-Scan and LenStar. AL-Scan (2.4 mm zone) was especially similar to VERION. Wide LOAs are potential contributors to axis error in patients with toric IOL implants.

Influences of Flap Shape and Hinge Angle on Opaque Bubble Layer Formation in Femtosecond Laser-Assisted LASIK Surgery.

PURPOSE: To evaluate the effects of different flap shapes and hinge angles on opaque bubble layer (OBL) formation using a femtosecond laser for flap creation in LASIK surgery. METHODS: This retrospective study evaluated 138 eyes of 73 patients who underwent femtosecond laser-assisted LASIK with a 150-kHz IntraLase femtosecond laser (Abbott Medical Optics, Inc., Santa Ana, CA) for myopic astigmatism and compared differences between different flap shapes and hinge angles on OBL formation. The surgical procedures were videotaped, and the patterns and sizes of the OBLs seen during surgery were analyzed. Preoperative and postoperative data including patient demographics, refractive status, keratometry, central corneal thickness, and intraoperative data (flap size and pocket parameters) were recorded. The eyes were divided into four groups based on the corneal flap shape (elliptical versus round) and hinge angle (50° versus 60°). RESULTS: The preoperative demographic data, mean spherical errors, cylindrical power, and central corneal thickness were not significantly different among the groups. Of the 138 eyes, 107 (77%) developed an OBL covering a mean area of 13.8% ± 12.6% in each case. This area was significantly smaller in the elliptical flap with 60° hinge angle group (P < .05). CONCLUSIONS: An oval-shaped flap with a larger hinge angle tended to result in less OBL formation in femtosecond laser-assisted LASIK. [J Refract Surg. 2017;33(3):178-182.].

A comparison of three different corneal marking methods used to determine cyclotorsion in the horizontal meridian.

During toric intraocular lens (IOL) implantation, surgeons must take particular care to ensure that inaccurate preoperative measurement and intraoperative misalignment do not cause unexpected postoperative residual astigmatism. This retrospective, comparative case series study aimed to analyze the rotational deviation, or cyclotorsion, of three corneal marking methods: VERION digital marker (VDM; reference), horizontal slit beam marking (HSBM), and subjective direct visual marking (SDVM) on the table (using a bevel knife tip). Subjects included 81 eyes of 61 patients (mean age: 65.70±13.14 years; range: 32-91 years) undergoing scheduled cataract surgery. A preoperative reference image was taken of each eye. Subsequently, a slit lamp with the light beam turned to the horizontal meridian was used to align the seated patient's head, and two reference marks were placed at the 3- and 9-o'clock positions of the corneal limbus using a 27-gauge needle and marking pen (HSBM). Upon transfer to the surgical table, the VDM was used to display a real-time dial scale on the patient's eye, with the entrance of the temporal clear corneal incision (CCI) at 0° (horizontal meridian). Simultaneously, a bevel knife tip was used to create a marker based on the surgeon's visual determination of the temporal 0° point (SDVM). We used the VDM to quantitatively evaluate the accuracy of axis alignment via deviation from the horizontal reference meridian. Compared with the reference meridian, the SDVM (-3.46°±7.32°, range: -18° to 13°) exhibited greater average relative cyclotorsion versus the HSBM (0.41°±4.92°, range: -10° to 10°). Furthermore, the mean average misalignment was significantly less in the HSBM group versus the SDVM group (t=4.179, P<0.001). The VDM is likely a reliable marking method, similar to the HSBM. In contrast, the SDVM is not entirely reliable. The VDM usage may prevent inaccurate preoperative manual marking during toric IOL implantation.

Blood pressure change during phacoemulsification and femtosecond laser-assisted cataract surgery.

AIM: To evaluate blood pressure (BP) changes during phacoemulsification (PC) and femtosecond laser (FSL)-assisted cataract surgery. METHODS: A retrospective chart review was performed for all patients who received traditional phacoemulsification surgery (PC group) and FSL-assisted cataract surgery (FS group) from July 2013 to December 2014. Totally 206 eyes from 133 patients receiving the two types of procedures were included. Patient characteristics (age, gender, and hypertension history), pre- and post-operative BPs were collected. RESULTS: The pro-operative systolic and diastolic BPs (mm Hg) were 124.89±20.48 vs 126.98±16.85, and 71.88±9.81 vs 73.56±10.03, in PC and FS groups, respectively. While the post-operative systolic and diastolic BPs (mm Hg) were 130.13±22.59 vs 134.77±17.52, and 73.41±11.62 vs 78.89±12.2, in PC and FS groups, respectively. Paired-sample t-tests showed obvious systolic and diastolic BP elevations in FS group after surgery (P=0.001 and 0.007) and no reliability in PC group (P=0.094 and 0.359). A linear regression model revealed systolic and diastolic BP elevations, which were related to longer surgical times for FS group (P=0.008 and 0.021). Age, gender, and hypertension history were not correlated with blood pressure elevation in either group. CONCLUSION: BP increases but at a limited level after FSL-assisted cataract surgery compared to traditional phacoemulsification.

Ultracompact polarization rotator in an asymmetric single dielectric loaded rib waveguide.

A compact polarization rotator (PR) with an asymmetric single dielectric loaded rib waveguide is proposed. The core of the waveguide is designed to have a specific rectangular configuration. The waveguide requires only a single asymmetrical dielectric loading on the core to complete the polarization conversion. The optical field is confined to the vicinity of the core center, which matches the optical field of the input/output waveguides. The transition loss of the PR is as low as 0.03-0.21 dB/facet without the taper or offset schemes. Such results can facilitate the fabrication of a PR with an operating length of 10 µm. In a comprehensively designed PR with a length of 7.92 µm, a -1 dB bandwidth for polarization conversion efficiency (PCE) is greater than 100 nm at the communicating wavelength of 1550 nm. The loading width and thickness with ±20 nm tolerance exhibit -0.87 and -0.49 dB changes in PCE, respectively.

Readmission to the intensive care unit: a population-based approach.

BACKGROUND/PURPOSE: Readmission to the intensive care unit (ICU) results in increased consumption of medical resources and costs, and has been proposed as a marker for quality of care. ICU readmission rates have been estimated at 4-14% and different risk factors have been proposed by various studies. METHODS: Every admission event to the ICU was recorded and readmission episodes were analyzed using a population-based database from the Taiwan National Health Insurance Research Database (NHIRD) for the period from January 1, 2006 to December 31, 2006. RESULTS: The average follow-up time was 206.35 days. From the database of 192,201 patients admitted to the ICU, 25,263 patients were re-admitted, with a readmission rate of 13.13%. The leading etiologies for readmission were identified. Using multivariate analysis, age > 39 years old, female gender, ischemic heart disease, lung related disorders, pneumonia, cerebrovascular disease, sepsis, heart failure, chronic liver disease, diabetes mellitus, and chronic obstructive pulmonary disease were identified as significant risk factors for readmission to the ICU. CONCLUSION: This study uses a novel approach to assess risk factors for readmission to the ICU. Higher risk patients should be assessed more carefully before discharge or transfer from the ICU to prevent readmission episodes.

Acute renal failure in severe pancreatitis: A population-based study.

INTRODUCTION: Acute pancreatitis (AP) is a common illness with varied mortality and morbidity. Patients with AP complicated with acute renal failure (ARF) have higher mortality than patients with AP alone. Although ARF has been proposed as a leading mortality cause for AP patients admitted to the ICU, few studies have directly analyzed the relationship between AP and ARF. METHODS: We performed a retrospective study using the population-based database from the Taiwan National Health Insurance Research Database (NHIRD). In the period from 1 January 2005 to 31 December 2005, every patient with AP admitted to the ICU was included and assessed for the presence of ARF and mortality risk. RESULTS: In year 2005, there were a total of 221,101 admissions to the ICU. There were 1,734 patients with AP, of which 261 (15.05%) patients also had a diagnosis of ARF. Compared to sepsis and other critical illness, patients with AP had a higher risk of having a diagnosis of ARF, and patients with both diagnoses had a higher mortality rate in the same ICU hospitalization. CONCLUSION: AP is associated with a higher risk of ARF, and, when both conditions exist, a higher risk of mortality is present.

Impact of telepresence levels on internet advertising effects.

This study examined the dimensions of interactivity and vividness to propose three telepresence levels: content presence, social presence, and personal presence. Then, an experiment investigated the impact of different telepresence levels on Internet advertising. The effects of interactions between vividness of visual imagery (VVI) and product types in relation to telepresence levels and advertising effects were also analyzed. The study employed a factorial design: 4 (levels of telepresence) x 2 (product types) x 2 (VVI). Levels of telepresence and product types were both manipulated between subjects. VVI was measured within subjects. Experimental findings showed that high levels of telepresence of an Internet advertisement increased subject recall and recognition. The low VVI respondent group would have greater recognition than traditional advertisements when respondents were exposed above the level 2 (social presence) advertisement and the effect of recognition increased from level 1 (content presence) to level 3 (personal presence). Recognition increased from level 1 (content presence) to level 2 (social presence) for both search and experience product groups; however, only recognition of the experience product group increased in level 3 (personal presence).