Safety and Effectiveness of Smooth Incision Lenticular Keratomileusis (SILKTM) Using the ELITA(TM) Femtosecond Laser System for Correction of Myopic and Astigmatic Refractive Errors.

Purpose: To evaluate visual outcomes following the Smooth Incision Lenticular Keratomileusis (SILKTM) procedure for correction of myopic refractive errors with and without astigmatism, using the ELITATM Femtosecond Laser System. Patients and Methods: A prospective, multicenter, single-arm, open-label clinical study was conducted. Eighty-five myopic subjects (n = 170 eyes), aged 18 years or older, with manifest refractive spherical equivalent (MRSE) up to -12.00 D and astigmatism up to -6.00 D, were treated binocularly using the ELITA femtosecond laser and followed up for 6 months. Intended correction was emmetropia for all eyes. The primary outcome measures included post-operative uncorrected and corrected distance visual acuity (UDVA and CDVA). Secondary outcome measures included surgeon's rating for ease of lenticule extraction, predictability, safety, and stability. Results: A total of 170 eyes of 85 patients underwent SILK. Preoperative mean MRSE was -4.14 D ± 1.32 D (range -1.38 D to -8.88 D) and the mean cylinder was -0.77 D ± 0.62 D. Intraoperative surgeon ease of lenticule dissection was rated as grade 0 or 1 in 85.3% of eyes (no/only mild dissection needed). UDVA at 1 day, 1 week, 1 month, and 6 months was 20/20 or better in 65.9%, 85.4%, 91.5%, and 96% of eyes, respectively. No eyes lost any lines of CDVA at 6 months compared to the preoperative. The postoperative MRSE was stable over time, ranging from -0.34 D ± 0.24 D at 1 month to -0.33 D ± 0.23 D at 6 months. MRSE predictability (± 0.50 D) was 93.5% (129/138) at 3 months and 91.1% (113/124) at 6 months. No serious adverse events were noted. Conclusion: The SILK procedure with the ELITA Femtosecond Laser System is safe and effective for the treatment of myopic refractive errors with and without astigmatism. Fast visual recovery was demonstrated, with stability achieved by 3 months.

Use and barriers to the use of telehealth services in the Arab population in Israel: a cross sectional survey.

BACKGROUND: Studies conducted in Israel and in other countries show that minority populations typically underuse telehealth services notwithstanding the advantages inherent in the use of these services. The goal of this study was to examine telehealth use patterns and the barriers to the use of telehealth services in the Arab population in Israel, which is a culturally and ethnically varied minority population with a unique language and culture. METHODS: A telephone survey was conducted among a representative sample of the adult Arab population in Israel from October 29 to November 4, 2020. Of the randomly sampled 1,192 adult Israeli Arabs 501 participants responded to the entire questionnaire, representing a response rate of 42%. RESULTS: The study found that the majority of the adult Arab population in Israel faced no technology or Internet accessibility barriers. Thus, the majority of adult Israeli Arabs (87%) use the Internet on a daily basis and have smartphones (96%) and an Internet connection (93%). However, although they have high technology and Internet accessibility, their use of telehealth services is mostly a telephone appointment with a doctor (66%). At the same time, significantly lower use rates were found with regard to advanced telehealth services delivered through the Internet, e.g., consultation with a health care provider by email or chat (34%) or video chat (8%) and ordering of medications (14%). It was found that Arab Christians are more likely to use digital services than Arab Muslims, even when background characteristics are statistically controlled. Lack of awareness was found to be the major barrier to the use of telehealth services, specifically advanced services such as ordering of medications (23%) and video medical consultation (15%). A high rate of women cited the unmet need for the discreet provision of telehealth services as a barrier to their use of the services. It was also found that the majority of the adult Arab population had no objection in principle to the use of email or chat (75%) or video chat (51%) for consultation with a health care provider. It was further found that facilitating factors promoting the use of telehealth services include previous acquaintance with the health care provider, a stable internet infrastructure, the provision of the services in the Arabis language, guidance in the use of the service, a recommendation by a health care provider, and the participation of a family member in the online medical consultation. CONCLUSIONS: The study findings highlight the need for the provision of accessible and customized telehealth services for minority populations. Whether delivered over the phone or through the Internet, the services have to be culturally (for Muslims and Christians) and linguistically (Arabic) adapted, guidance in the use of the services should be provided, and service marketing should be tailored to the target minority population. Specific solutions should be developed for the discreet provision of telehealth services for women, maintaining their privacy in online consultation with a health care provider, while the option of having a family member participate in the online medical consultation should be clearly indicated. In addition, awareness of telehealth services should be enhanced through promotional activities culturally adapted to the Arab society, for instance, through recommendation by the family doctor.

Performance of a Translucent Activator for LipiFlow Vectored Thermal Pulse (VTP) Treatment of Meibomian Gland Dysfunction.

Purpose: Investigator feedback was used to assess the clinical use of the LipiFlow® System with the new translucent Activator Clear to successfully complete LipiFlow® treatments. Patients and Methods: This was a prospective, open-label clinical investigation. A total of 88 eyes (44 subjects) were treated using the LipiFlow® System with the new Activator Clear. Subjects diagnosed with bilateral meibomian gland dysfunction (MGD) were enrolled in the study. Each investigator performed a complete LipiFlow® treatment with the translucent Activator on both eyes of each subject. Investigators completed a questionnaire assessing the clinical use of the Activator Clear on a 5-point scale (1 - very difficult or strongly disagree, 3 - neutral, 5 - very easy or strongly agree). Results: The new translucent Activator provided successful LipiFlow® treatments in 100% of cases, with 95% confidence interval of (96%, 100%). Additionally, the investigators agreed or strongly agreed that the translucent components of the Activator Clear made it easy to access and position the activator with confidence on the subject's eye. Conclusion: The overall investigators' impressions on usage and functionality of LipiFlow® System with the translucent Activator were very positive. The Activator Clear enables doctors with efficient and confident positioning around patient eyelids to ensure successful LipiFlow® treatment when used as indicated.

Wide-field imaging of retinal vasculature using optical coherence tomography-based microangiography provided by motion tracking.

Optical coherence tomography (OCT)-based optical microangiography (OMAG) is a high-resolution, noninvasive imaging technique capable of providing three-dimensional in vivo blood flow visualization within microcirculatory tissue beds in the eye. Although the technique has demonstrated early clinical utility by imaging diseased eyes, its limited field of view (FOV) and the sensitivity to eye motion remain the two biggest challenges for the widespread clinical use of the technology. Here, we report the results of retinal OMAG imaging obtained from a Zeiss Cirrus 5000 spectral domain OCT system with motion tracking capability achieved by a line scan ophthalmoscope (LSO). The tracking LSO is able to guide the OCT scanning, which minimizes the effect of eye motion in the final results. We show that the tracking can effectively correct the motion artifacts and remove the discontinuities and distortions of vascular appearance due to microsaccade, leading to almost motion-free OMAG angiograms with good repeatability and reliability. Due to the robustness of the tracking LSO, we also show the montage scan protocol to provide unprecedented wide field retinal OMAG angiograms. We experimentally demonstrate a 12 x 16 mm² retinal OMAG angiogram acquired from a volunteer, which is the widest FOV retinal vasculature imaging up to now in the community.

Widefield En Face Optical Coherence Tomography Imaging of Subretinal Drusenoid Deposits.

BACKGROUND AND OBJECTIVE: To determine whether subretinal drusenoid deposits (SDD) can be detected on widefield en face slab images derived from spectral-domain (SD) and swept-source (SS) optical coherence tomography (OCT) volume scans. PATIENTS AND METHODS: Retrospective study of patients with dry age-related macular degeneration (AMD) enrolled prospectively in an OCT imaging study using SD-OCT (Cirrus HD-OCT; Carl Zeiss Meditec, Dublin, CA) with a central wavelength of 840 nm, and a prototype 100-kHz SS-OCT instrument (Carl Zeiss Meditec) with a central wavelength of 1,050 nm. Seven en face slabs were evaluated with thicknesses from 20 to 55 µm and positioned at distances up to 55 µm above the retinal pigment epithelium (RPE). A montage of 6 × 6 mm SD-OCT en face images of the posterior pole from each patient was compared with a 9 × 12 mm SS-OCT single en face slab image and with color, autofluorescence, and infrared reflectance images. RESULTS: A total of 160 patients (256 eyes) underwent scanning with both OCT instruments; 57 patients (95 eyes) also underwent multimodal fundus imaging. Of 95 eyes, 32 (34%) were diagnosed with reticular pseudodrusen (RPD) using multimodal imaging. All eyes with RPD demonstrated a pattern of SDD on widefield en face OCT similar to that observed for RPD. The en face slab image that consistently identified SDD was the 20-µm thick slab with boundaries from 35 to 55 µm above the RPE. CONCLUSION: Widefield en face slab imaging with SD-OCT and SS-OCT can detect SDD and could replace multimodal imaging for the diagnosis of RPD in the future.

Swept-source OCT angiography of macular telangiectasia type 2.

BACKGROUND AND OBJECTIVE: To evaluate the central macular microvascular network in patients with macular telangiectasia type 2 (MacTel2) using optical coherence tomography (OCT)-based microangiography (OMAG). PATIENTS AND METHODS: Prospective, observational study of patients with MacTel2 evaluated using a swept-source OCT (SS-OCT) prototype. OMAG was performed using a 3 mm × 3 mm central foveal raster scan. The algorithm segmented the retina into three layers. Microvascular distribution was depicted as en face images, and qualitative information was compared to fluorescein angiography (FA) images. RESULTS: OMAG detected abnormal microvasculature in all MacTel2 eyes, predominantly in the middle retinal layers with neovascularization in the outer retina. These vessels correlated well with the FA alterations. The abnormal temporal, juxtafoveal microvasculature in MacTel2 became apparent as the disease progressed and in later stages tended to extend circumferentially, with anastomotic vessels temporally. CONCLUSION: OMAG provided detailed, depth- resolved information about the perifoveal macular microvasculature in MacTel2. In most cases, images were better using OMAG than FA. The OMAG images demonstrated that most of the leakage seen on FA appeared to arise from the abnormal perifoveal microvasculature in the middle retinal layer.

Swept-source OCT angiography of the retinal vasculature using intensity differentiation-based optical microangiography algorithms.

BACKGROUND AND OBJECTIVE: To demonstrate the feasibility of using a 1,050-nm swept-source optical coherence tomography (SS-OCT) system to achieve noninvasive retinal vasculature imaging in human eyes. MATERIALS AND METHODS: Volumetric data sets were acquired using a 1-µm SS-OCT prototype that operated at a 100-kHz A-line rate. A scanning protocol designed to allow for motion contrast processing, referred to as OCT angiography or optical microangiography (OMAG), was used to scan an approximately 3 × 3­mm area in the central macular region of the retina within approximately 4.5 seconds. An intensity differentiation-based OMAG algorithm was used to extract three-dimensional retinal functional microvasculature information. RESULTS: Intensity signal differentiation generated capillary-level resolution en face OMAG images of the retina. The parafoveal capillaries were clearly visible, thereby allowing visualization of the foveal avascular zone in healthy subjects. CONCLUSION: The capability of OMAG to produce retinal vascular images was demonstrated using the 1-µm SS-OCT prototype. This technique has potential clinical value for studying retinal vasculature abnormalities.

Association between local neuroretinal function and control of adolescent type 1 diabetes.

PURPOSE: To evaluate associations between neuroretinal function measured with multifocal electroretinogram (mfERG) and disease variables in adolescents with type 1 diabetes and no retinopathy. METHODS: Fundus photographs, blood glucose (BG) concentration, HbA1c, and monocular mfERG were performed on 115 adolescent patients (mean age ± SD; 15.7 ± 1.8 years) and 30 controls (18.0 ± 2.8 years). All subjects had best-corrected visual acuity ≥ 20/20. The 45° mfERG stimulus included 103 hexagons, reversing between dark and bright according to a pseudorandom m-sequence. Amplitudes (AMPs) and implicit times (ITs) were derived from local mfERG response waveforms, and Z-scores were calculated. Retinal maps of abnormality frequencies were generated. Differences between controls and patients were evaluated using t-tests. Associations between mfERG and age, duration, and diabetes control were examined using linear regression analysis. RESULTS: Mean mfERG IT was significantly longer in the patients compared with that in the controls (P = 0.019), but AMP was not different (P > 0.05). In all, 26 eyes (23%) of the patients had abnormal IT and 3 eyes (3%) had abnormal AMP. IT abnormalities were essentially distributed randomly across the retina. There were too few AMP abnormalities to examine their retinal distribution. IT was positively correlated with HbA1c (P < 0.0002) but not correlated with diabetes duration, BG, or age. CONCLUSIONS: Higher long-term blood glucose concentration is associated with degraded neuroretinal function in adolescents with type 1 diabetes and no retinopathy. Over 20% of these patients have abnormal neuroretinal function. It will be important to determine longitudinally whether the relationship between mfERG IT and diabetes control exists within individual adolescent patients.

Interocular symmetry of abnormal multifocal electroretinograms in adolescents with diabetes and no retinopathy.

PURPOSE: To investigate, in adolescents with type 1 diabetes and no retinopathy, the spatial correspondence between abnormal multifocal electroretinogram (mfERG) responses in the two eyes. METHODS: mfERG and fundus photographs were measured in both eyes of 68 adolescents with type 1 diabetes and no retinopathy (13 to 19 years old; best corrected visual acuity ≥ 20/20), and 30 age-matched controls. The mfERG stimulus was comprised of 103 hexagons, and subtended 45°. mfERG implicit times (IT) and amplitudes (AMP) were derived. Fifteen patients for IT, and five for AMP with at least one eye defined as abnormal (six or more locations with abnormal Z-scores; P < 0.03) were analyzed. RESULTS: Nasal retina had significantly more abnormal IT locations compared with temporal retina (P = 0.015), and the opposite was true with regard to abnormal AMP (P < 0.001). The proportion of abnormal responses in the superior retina was not significantly different from that in the inferior retina (P > 0.1 for IT and AMP). Interocular correspondence of locations with abnormal mfERG IT was significant for all 15 patients (P values <0.0001-0.012), and agreement between eyes was 68% to 94% (AC1 agreement coefficient: 0.48-0.94). Overall interocular correspondence was also significant (P < 0.0002), with 86% agreement (AC1 = 0.76). Overall interocular correspondence of locations with abnormal mfERG AMP was also significant (P < 0.0002). CONCLUSIONS: Interocular spatial correspondence of abnormal mfERG responses exists in adolescents with type 1 diabetes and no retinopathy. This is most apparent for IT abnormalities. This correspondence could be used in clinical trials, and raises the possibility of initiating treatment in both eyes at early disease stages as new topical treatments emerge.

Comparison of optical coherence tomography and scanning laser polarimetry measurements in patients with multiple sclerosis.

PURPOSE: To compare optical coherence tomography (OCT) and scanning laser polarimetry (GDx) measurements of the retinal nerve fiber layer (RNFL) in multiple sclerosis (MS) patients with and without optic neuritis (ON). METHODS: OCT and GDx were performed on 68 MS patients. Qualifying eyes were divided into two groups: 51 eyes with an ON history > or =6 months before (ON eyes) and 65 eyes with no history of ON (non-ON eyes). Several GDx and OCT parameters and criteria were used to define an eye as abnormal, for example, GDx nerve fiber indicator (NFI) >20 or 30, OCT average RNFL thickness, and GDx temporal-superior-nasal-inferior-temporal average (TSNIT) below 5 or 1% of the normative database of the instruments. Agreement between OCT and GDx parameters was reported as percent of observed agreement, along with the AC1 statistic. Linear regression analyses were used to examine the relationship between OCT average RNFL thickness and GDx NFI and TSNIT. RESULTS: All OCT and GDx measurements showed significantly more RNFL damage in ON than in non-ON eyes. Agreement between OCT and GDx parameters ranged from 69 to 90% (AC1 0.37 to 0.81) in ON eyes and 52 to 91% (AC1 = 0.21 to 0.90) in non-ON eyes. Best agreement was observed between OCT average RNFL thickness (p < 0.01) and NFI (>30) in ON eyes (90%, AC1 = 0.81) and between OCT average RNFL thickness (p < 0.01) and GDx TSNIT average (p < 0.01) in non-ON eyes (91%, AC1 = 0.90). In ON eyes, the OCT average RNFL thickness showed good linear correlation with NFI (R = 0.69, p < 0.0001) and TSNIT (R = 0.55, p < 0.0001). CONCLUSIONS: OCT and GDx show good agreement and can be useful in detecting RNFL loss in MS/ON eyes.

Comparison of multifocal visual evoked potential, standard automated perimetry and optical coherence tomography in assessing visual pathway in multiple sclerosis patients.

BACKGROUND: Multifocal visual evoked potentials (mfVEP) measure local response amplitude and latency in the field of vision. OBJECTIVE: To compare the sensitivity of mfVEP, Humphrey visual field (HVF) and optical coherence tomography (OCT) in detecting visual abnormality in multiple sclerosis (MS) patients. METHODS: mfVEP, HVF, and OCT (retinal nerve fiber layer [RNFL]) were performed in 47 MS-ON eyes (last optic neuritis [ON] attack >or=6 months prior) and 65 MS-no-ON eyes without ON history. Criteria to define an eye as abnormal were: (1) mfVEP amplitude/latency - either amplitude or latency probability plots meeting cluster criteria with 95% specificity; (2) mfVEP amplitude or latency alone (specificity: 97% and 98%, respectively); and (3) HVF and OCT, mean deviation and RNFL thickness meeting p < 0.05, respectively. RESULTS: MfVEP (amplitude/latency) identified more abnormality in MS-ON eyes (89%) than HVF (72%), OCT (62%), mfVEP amplitude (66%) or latency (67%) alone. Eighteen percent of MS-no-ON eyes were abnormal for both mfVEP (amplitude/latency) and HVF compared with 8% with OCT. Agreement between tests ranged from 60% to 79%. mfVEP (amplitude/latency) categorized an additional 15% of MS-ON eyes as abnormal compared with HVF and OCT combined. CONCLUSIONS: mfVEP, which detects both demyelination (increased latency) and neural degeneration (reduced amplitude), revealed more abnormality than HVF or OCT in MS patients.

Assessing visual pathway function in multiple sclerosis patients with multifocal visual evoked potentials.

Multifocal visual evoked potentials provide a topographic measure of visual response amplitude and latency. The objective of this study was to evaluate the sensitivity and specificity of the multifocal visual evoked potential technique in detecting visual abnormalities in patients with multiple sclerosis. Multifocal visual evoked potentials were recorded from 74 patients with multiple sclerosis with history of optic neuritis (MS-ON, n = 74 eyes) or without (MS-no-ON, n = 71 eyes), and 50 normal subjects (controls, n = 100 eyes) using a 60-sector pattern reversal dartboard stimulus (VERIS). Amplitude and latency for each sector were compared with normative data and assigned probabilities. Size and location of clusters of adjacent abnormal sectors (p < 0.05) were examined. Mean response amplitudes were (+/- SE) 0.39 +/- 0.02, 0.53 +/- 0.02, and 0.60 +/- 0.01 for MS-ON, MS-no-ON, and control groups, respectively, with significant differences between all groups (p < 0.0001). Mean latencies (ms; +/-SE relative to normative data) were 12.7 +/- 1.3 (MS-ON), 4.3 +/- 1.1 (MS-no-ON), and 0.3 +/- 0.4 (controls); group differences again significant (p < 0.0001). Half the MS-ON eyes had clusters larger than five sectors compared with 13% in MS-no-ON and 2% in controls. Abnormal sectors were distributed diffusely, although the largest cluster was smaller than 15 sectors in two-thirds of MS-ON eyes. Cluster criteria combining amplitude and latency showed an area of 0.96 under the receiver operating characteristic curve, yielding a criterion with 91% sensitivity and 95% specificity. We conclude that the multifocal visual evoked potential provides high sensitivity and specificity in detecting abnormalities in visual function in multiple sclerosis patients.

The effect of eccentricity on the contrast response function of multifocal visual evoked potentials (mfVEPs).

mfVEPs were recorded with a 22 degrees radius, 60 sector pattern reversal dartboard stimulus (VERIS) at six contrast levels (10%, 25%, 35%, 50%, 75%, 95%). Contrast response functions (CRFs) based on response amplitudes were adequately described by a simple hyperbolic function. The effect of reducing contrast on the amplitude was most apparent in the central 1 degrees radius, which had a C(50) (contrast at 50% of the maximum response) in excess of 50%, compared to values for C(50) in more eccentric regions that were 30% or lower. Mean latency increased 6 (+/-0.7 SE) ms from the highest to the lowest contrast tested, and did not vary significantly with eccentricity.

Effects of fixation instability on multifocal VEP (mfVEP) responses in amblyopes.

The cortical activity of subjects with compromised central vision (e.g., amblyopes) is thought to be much weaker for stimulation of the affected eye than in the fellow eye. Because these subjects are known to exhibit considerable difficulties in keeping steady fixation, we investigated the effects of anomalous fixation on their multifocal visual-evoked potential (mfVEP) responses using a dual Purkinje image (dPi) eye tracker. Our results show that mfVEP responses to stimulation of the central 5 degrees were depressed in the affected eye compared to those in the normal eye and the magnitude of response reductions was proportional to the degree of visual acuity loss in amblyopic subjects. Fixation was far less stable while viewing with the affected eye than with the fellow eye, some exhibiting jerk nystagmus and/or saccadic oscillations. Normal subjects with artificially imposed nystagmus showed similar reductions of VEP responses. The relative magnitudes of the deficits in mfVEP responses were tightly correlated with the degree of fixation instability. These results suggest that the interpretation of anomalous neural or perceptual processing in amblyopic subjects must take the effects of unsteady fixation during measurements into consideration in order to reveal the true nature and extent of sensory neural deficits.

The relationship between visual field and retinal nerve fiber layer measurements in patients with multiple sclerosis.

PURPOSE: To investigate the relationship between visual function, measured by standard automated perimetry (SAP), and retinal nerve fiber layer (RNFL) thickness, measured by optical coherence tomography (OCT), in patients with multiple sclerosis (MS). METHODS: SAP and RNFL thickness were measured in patients with MS in 28 eyes with the last optic neuritis (ON) >or=6 months prior (ON group) and 33 eyes without ON history (non-ON group). Abnormal overall or quadrant RNFL thickness was defined by measured values below 5% of the norm. A whole visual field or a sector of the field was classified as abnormal by using cluster criteria on total-deviation plots. Agreement between SAP and OCT results in classifying eyes/sectors was presented as a percentage of observed agreement, along with the AC1 statistic, which corrects for chance agreement. Regression analyses were performed relating several SAP parameters and RNFL thickness in the ON group. RESULTS: ON eyes showed more loss of visual sensitivity (MD, P = 0.02) and more loss of RNFL thickness (P < 0.0001) than did non-ON eyes. SAP and OCT agreed in 86% (AC1 = 0.78) of eyes and 69% (AC1 = 0.38) of sectors in the ON group and 61% (AC1 = 0.33) of eyes and 66% (AC1 = 0.48) of sectors in the non-ON group. Overall RNFL thickness was related to MD (dB) by a simple exponential function (R(2) = 0.48), supporting a linear relationship between these measures when both are expressed on linear scales. Absolute Pearson correlation coefficients for overall RNFL thickness and several SAP parameters ranged from 0.51 to 0.69. CONCLUSIONS: Good agreement between SAP and OCT was found in ON eyes but not in non-ON eyes or in individual sectors in either group. The findings in this study provide further support for the utility of combining structural and functional testing in clinical research on patients with MS, as well as in future neuroprotection trials for which the anterior visual pathways in patients with MS and optic neuritis may be used as a model.