XXXIII. On cometary theory

Flare changes after intravitreal injection of ocriplasmin in symptomatic vitreomacular traction syndrome

PURPOSE

To evaluate the changes in anterior chamber flare after a single intravitreal injection of ocriplasmin (125 μg), in patients with symptomatic vitreomacular traction syndrome (VMT).

STUDY DESIGN

An institutional review board-approved single-center not randomized prospective study.

METHODS

Fifteen eyes of fifteen patients (9 women, 6 men) underwent intravitreal injection with ocriplasmin for symptomatic VMT (width of attachment ≤ 1500 μm). Anterior segment flare was measured with a laser flare meter (Kowa) before intravitreal injection and 1 day, 1 week, 1 month after injection. The changes in flare were analyzed; the resolution of VMT was evaluated with spectral-domain OCT.

RESULTS

The mean anterior chamber flare was 10.5 ± 1.9 photons per millisecond (photons/ms) before the injection. After 1 day it increased to 13.6 ± 2.7 photons/ms (p = 0.027) and after 1 week to 14.4 ± 2.5 photons/ms (p = 0.005); after 1 month it decreased to 12.3 ± 2.3 photons/ms (p = 0.123). At 1 day and 1 week after injection, mean anterior chamber flare of fellow eyes was significantly lower than study eyes, while at 1 month this difference was not significant (12.3 ± 2.3 vs. 10.5 ± 1.8 photons/ms, p = 0.124, for study and fellow eyes). There was no statistically significant difference in the changes in flare between women and men or between phakic (N = 10) and pseudophakic (N = 5) eyes. No eye demonstrated intraretinal damage at any time-point. Also, 9 eyes showed resolution of VMT while 6 eyes demonstrated persistence of VMT.

CONCLUSION

Our study shows that intravitreal injection of ocriplasmin can be a safe and effective approach to treat symptomatic VMT syndrome in selected patients.

Effects of nanoparticle heating on the structure of a concentrated aqueous salt solution

The effects of a rapidly heated nanoparticle on the structure of a concentrated aqueous salt solution are studied using molecular dynamics simulations. A diamond-like nanoparticle of radius 20 Å is immersed in a sodium-chloride solution at 20% above the experimental saturation concentration and equilibrated at T = 293 K and P = 1 atm. The nanoparticle is then rapidly heated to several thousand degrees Kelvin, and the system is held under isobaric-isoenthalpic conditions. It is observed that after 2-3 ns, the salt ions are depleted far more than water molecules from a proximal zone 15-25 Å from the nanoparticle surface. This leads to a transient reduction in molality in the proximal zone and an increase in ion clustering in the distal zone. At longer times, ions begin to diffuse back into the proximal zone. It is speculated that the formation of proximal and distal zones, and the increase in ion clustering, plays a role in the mechanism of nonphotochemical laser-induced nucleation.

Simulating colors of clear and partly cloudy skies

A model (SKYCOLOR) is developed that simulates the light and color of the sky and open cloud decks in the vertical plane including the Sun and the observer and animates the changes as the Sun goes down. Model skylight consists of sunbeams that are scattered toward the observer, but depleted by scattering and absorption in the Chappuis bands of ozone. SKYCOLOR includes the Earth's curvature, atmospheric refraction, cloud shadows, and solar eclipses. Scattering is given a wavelength (lambda) dependence of lambda(-4) for air molecules (Rayleigh scattering), lambda(-1) for tropospheric aerosols, and lambda(+1) for volcanic aerosol particles. Multiple scattering is calculated directly in clouds but is parameterized in clear air by decreasing the scattering rates of sunlight and of skylight in the Earth's shadow by 30%.