Acoustic Manipulation of Intraocular Particles

Various conditions cause dispersions of particulate matter to circulate inside the anterior chamber of a human eye. These dispersed particles might reduce visual acuity or promote elevation of intraocular pressure (IOP), causing secondary complications such as particle related glaucoma, which is a major cause of blindness. Medical and surgical treatment options are available to manage these complications, yet preventive measures are not currently available. Conceptually, manipulating these dispersed particles in a way that reduces their negative impact could prevent these complications. However, as the eye is a closed system, manipulating dispersed particles in it is challenging. Standing acoustic waves have been previously shown to be a versatile tool for manipulation of bioparticles from nano-sized extracellular vesicles up to millimeter-sized organisms. Here we introduce for the first time a novel method utilizing standing acoustic waves to noninvasively manipulate intraocular particles inside the anterior chamber. Using a cylindrical acoustic resonator, we show ex vivo manipulation of pigmentary particles inside porcine eyes. We study the effect of wave intensity over time and rule out temperature changes that could damage tissues. Optical coherence tomography and histologic evaluations show no signs of damage or any other side effect that could be attributed to acoustic manipulation. Finally, we lay out a clear pathway to how this technique can be used as a non-invasive tool for preventing secondary glaucoma. This concept has the potential to control and arrange intraocular particles in specific locations without causing any damage to ocular tissue and allow aqueous humor normal outflow which is crucial for maintaining proper IOP levels

Ocular Surface Temperature Profile of Eyes with Retinal Vein Occlusion

Retinal vein occlusion (RVO) results in ischemia followed by an inflammatory response. Both processes affect tissue temperature in opposite directions. Here, we evaluate the effect of RVO on the ocular surface temperature (OST) profile. Subjects with RVO were prospectively recruited. Healthy subjects without any ocular disease served as controls. The OST was determined using the Therm-App thermal imaging camera, and image processing software was employed to compute the mean temperature values of the medial canthus, lateral canthus, and cornea. We obtained thermographic images from 30 RVO subjects (30 eyes) and 148 controls (148 eyes). A univariate analysis found that eyes with RVO had significantly elevated OSTs compared to the controls (mean difference of 0.6 ± 0.3 Celsius, p < 0.05). However, this distinction between the groups lost statistical significance upon adjusting for possible confounders, including patient and environmental factors. These findings were confirmed with a post hoc case–control matched comparison. In conclusion, RVO does not seem to affect the OST. This might be due to the balance between inflammatory thermogenesis and heat constriction from ischemia in RVO. It is also possible that, in our cohort, the RVO pathophysiological processes involved were localized and did not extend to the anterior segment. Patient and environmental factors must be considered when interpreting the OST

Ocular Surface Temperature: Characterization in a Large Cohort of Healthy Human Eyes and Correlations to Systemic Cardiovascular Risk Factors

Purpose: To characterize ocular surface temperature (OST) in healthy eyes and its association with systemic risk factors of cardiovascular and ischemic heart disease. Methods: This prospective cross-sectional study included consenting subjects who were examined at the Institute for Medical Screening in Sheba Medical Center. A Therm-App™ thermal imaging camera (Opgal LTD, Israel) was used for OST acquisition, and the mean OST of the medial canthal, lateral canthal, and central cornea regions were measured. Room and body temperatures were also recorded. Past medical and ocular history as well as data from various clinical examinations performed at the same visit were obtained. Results: Thermographic images were obtained from 186 subjects, 150 of which were included in the final analysis. OST was significantly higher in the medial canthal, central cornea, and lateral canthal regions in people with a history of ischemic heart disease (p = 0.02, p = 0.02, and p = 0.03, respectively). There were no significant OST differences (ANOVA test) associated with the presence of hypertension, diabetes mellitus, or active smoking status. Conclusions: OST correlated positively with the presence of ischemic heart disease. This correlation, its pathophysiological base, and its clinical application warrants further investigation

Association between Rates of Retinal Nerve Fiber Layer Thinning and Previous Disc Hemorrhage in Glaucoma.

PurposeTo investigate the relationship between previous disc hemorrhage (DH) and subsequent rates of retinal nerve fiber layer (RNFL) thinning.DesignLongitudinal, observational cohort study.ParticipantsTwenty-eight patients with glaucoma and patients with suspected glaucoma who had a history of DH in 1 eye (unilateral DH), but not in the fellow eye, enrolled in the Diagnostic Innovations in Glaucoma Study and the African Descent and Glaucoma Evaluation Study were included.MethodsAll subjects underwent annual optic disc photography and semiannual spectral-domain OCT RNFL thickness measurements. Multivariable linear mixed-effects models were used to investigate the relationship between the presence of previous DH and RNFL thinning rates while adjusting for potential confounding factors, such as race, age, mean intraocular pressure (IOP), baseline disease severity, and central corneal thickness (CCT). The relationship between the timing of DH and the rates of RNFL thinning also was investigated in eyes with a history of DH.Main outcome measuresRates of global and local RNFL thinning.ResultsPrevious DH was significantly associated with faster RNFL thinning rates globally (-0.39 μm/year faster, P&nbsp;= 0.010), in DH quadrants (-0.77 μm/year faster, P&nbsp;= 0.012), and non-DH quadrants (-0.49 μm/year faster, P&nbsp;= 0.038) after adjustment for race, mean IOP, baseline age, baseline standard automated perimetry mean deviation, and CCT. Higher IOP was also significantly associated with faster thinning rates globally (-0.07 μm/year faster per 1 mmHg higher, P&nbsp;= 0.047) and in DH quadrants (-0.10 μm/year faster per 1 mmHg higher, P&nbsp;= 0.044). In eyes with a history of DH, the time elapsed from the latest DH episode to the first OCT examination was not significantly associated with the rate of RNFL thinning.ConclusionsA history of DH is an independent risk factor for faster rates of RNFL thinning in non-DH quadrants and in DH quadrants; this risk is present even in eyes that exhibited DH several years earlier

Association between Rates of Retinal Nerve Fiber Layer Thinning and Previous Disc Hemorrhage in Glaucoma.

PurposeTo investigate the relationship between previous disc hemorrhage (DH) and subsequent rates of retinal nerve fiber layer (RNFL) thinning.DesignLongitudinal, observational cohort study.ParticipantsTwenty-eight patients with glaucoma and patients with suspected glaucoma who had a history of DH in 1 eye (unilateral DH), but not in the fellow eye, enrolled in the Diagnostic Innovations in Glaucoma Study and the African Descent and Glaucoma Evaluation Study were included.MethodsAll subjects underwent annual optic disc photography and semiannual spectral-domain OCT RNFL thickness measurements. Multivariable linear mixed-effects models were used to investigate the relationship between the presence of previous DH and RNFL thinning rates while adjusting for potential confounding factors, such as race, age, mean intraocular pressure (IOP), baseline disease severity, and central corneal thickness (CCT). The relationship between the timing of DH and the rates of RNFL thinning also was investigated in eyes with a history of DH.Main outcome measuresRates of global and local RNFL thinning.ResultsPrevious DH was significantly associated with faster RNFL thinning rates globally (-0.39 μm/year faster, P&nbsp;= 0.010), in DH quadrants (-0.77 μm/year faster, P&nbsp;= 0.012), and non-DH quadrants (-0.49 μm/year faster, P&nbsp;= 0.038) after adjustment for race, mean IOP, baseline age, baseline standard automated perimetry mean deviation, and CCT. Higher IOP was also significantly associated with faster thinning rates globally (-0.07 μm/year faster per 1 mmHg higher, P&nbsp;= 0.047) and in DH quadrants (-0.10 μm/year faster per 1 mmHg higher, P&nbsp;= 0.044). In eyes with a history of DH, the time elapsed from the latest DH episode to the first OCT examination was not significantly associated with the rate of RNFL thinning.ConclusionsA history of DH is an independent risk factor for faster rates of RNFL thinning in non-DH quadrants and in DH quadrants; this risk is present even in eyes that exhibited DH several years earlier

β-Zone Parapapillary Atrophy and Rates of Glaucomatous Visual Field Progression: African Descent and Glaucoma Evaluation Study.

Importanceβ-zone parapapillary atrophy (βPPA) has been reported as a risk factor for glaucoma onset and progression. Previous studies have shown that the prevalence of βPPA differs between individuals of African descent (AD) and European descent (ED).ObjectiveTo test whether the association between the presence and progression of βPPA vs visual field progression of glaucoma differs between these 2 ancestry groups.Design, setting, and participantsIn a prospective, multicenter, longitudinal cohort study, 634 individuals (1090 eyes) enrolled in the African Descent and Evaluation Study (ADAGES) with a diagnosis of glaucomatous optic neuropathy (GON) or ocular hypertension (OHT) and at least 2 disc stereophotographs were included. Two graders masked to clinical and ancestry data reviewed and graded the baseline and last disc stereophotographs for the presence of βPPA at baseline and βPPA progression (development or enlargement). Mixed-effects linear models were tested with visual field mean deviation as a dependent variable and time (alone and with interaction terms) as independent variables. ADAGES enrollment began in January 2003 and ended in July 2006; follow-up ended in 2016.ExposuresDisc stereophotographs.Main outcomes and measuresProgression of βPPA in AD and ED individuals.ResultsIn 634 patients, a total of 814 eyes of AD (395 eyes) and ED (419) patients with GON and 276 eyes of AD (106) and ED (170) patients with OHT who were enrolled in ADAGES were analyzed. There were 336 (53.0%) women in the study; mean (SD) age was 61.9 (12.7) years. In the OHT group, the association between βPPA at baseline and visual field progression was not significantly different between AD and ED eyes (β = 0.071; 95% CI, -0.016 to 0.158; P = .11), nor was the association between βPPA progression and visual field progression (β = 0.020; 95% CI, -0.465 to 0.506; P = .93). In the GON group, ED eyes with baseline βPPA progressed faster than did AD eyes with baseline βPPA (β = -0.124; 95% CI, -0.241 to -0.007; P = .04), although the association between βPPA progression and visual field progression did not differ significantly between race groups (β = -0.101; 95% CI, -0.323 to 0.119; P = .37).Conclusions and relevanceRace had a significant effect on the association between baseline βPPA and rates of visual field progression in eyes with GON. Progression of βPPA was not associated with faster visual field progression in either racial group