Calcification of hydrophilic intraocular lens following Descemet's membrane endothelial keratoplasty (DMEK) using intracameral injection of air or gas: a possible explanation

Session Details

Session Title: Presented Poster Session: IOL Opacification

Venue: Poster Village: Pod 1

First Author: : P.Gartaganis GREECE

Co Author(s): :    P. Natsi   S. Alimisi   S. Gartaganis   P. Koutsoukos              

Abstract Details

Purpose:

To explain the calcification’s mechanism of hydrophilic acrylic intraocular lenses (IOLs) following Descemet membrane endothelial keratoplasty (DMEK) involving intracameral air or gas.

Setting:

1. From the Department of Ophthalmology, 2. the Department of Chemical Engineering, Laboratory of Inorganic and Analytical Chemistry, University of Patras and FORTH-ICEHT, Greece and 3. 2nd Department of Ophthalmology, Henry Dunant Hospital, Athens, Greece

Methods:

Computational air/fluid dynamics tried to explain the physics phenomena when anterior chamber is completely pressurized with air less than 30-40 mmHg for at least 10-60 minutes with the presence of a hydrophilic IOL. Past a period of time, typically 10 -15 minutes, the bubble is reduced to 80–90% of the anterior chamber volume so that it encompasses the entire pupil and hydrophilic IOL surface. In rebubbling techniques, the anterior chamber was left from 30, 60 to 140 minutes with complete air, followed by 80-90% air-liquid exchange to reduce the air bubble.

Results:

The formation of a stable thin aqueous humor film (≈75-600 μm) on hydrophilic IOL surface during the procedure is critical. Because of the confinement of the aqueous humor by surfaces with curvature, the concomitant supersaturation with respect to calcium phosphate, is higher than the normal value of the aqueous humor. This, in combination with the disjoining pressure, provides the thermodynamic driving force needed for the formation of calcium phosphate crystallites. The locally developed supersaturation on the IOL surface in contact with the aqueous humor film is inversely proportional to the curvature of the liquid film (i.e. low curvature- high supersaturation).

Conclusions:

The disjoining pressure and the concomitant increase of the supersaturation with respect to calcium phosphate trigger the calcification of hydrophilic IOLs following DMEK surgery. In our opinion, calcification on the surface of the hydroxylated-hydrated polymer surfaces is boosted through the development of a locally higher supersaturation than the one shown in our earlier reports to be sufficient for the calcification of the hydrophilic IOLs by the bulk aqueous humor.

Financial Disclosure:

None