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Laser photocoagulation

Laser-Ocular Media Interaction during photocoagulation

          Choroidal neovascularization (CNV) in exudative age-related macular degeneration (AMD) is the leading cause of blindness. Until recently, laser photocoagulation was the only well-established and widely accepted treatment for AMD. However, it has a high rate of CNV persistence and recurrence and results in iatrogenic, collateral damage to the overlying retina. Numerical studies of photocoagulation is being studied to compare the effect of latest technique pulsed lasers with conventional laser treatment in minimizing the damage to the inner and outer bands of neural retina. The research aims at finding optimum laser parameters for selective treatment of retinal pigment epithelium (RPE) sparing neural retina. Due to symmetry of the problem two dimensional axi-symmetric eye model was developed as shown in the fig.1.

           The Figures 2 and 3 show the energy and temperature distribution for continuous wave and pulsed (10% duty factor) laser respectively.  The temperature rise for 10% duty factor at the RPE is higher than that of continuous wave laser. This shows that only RPE can be destroyed by use of pulsed laser without a significant rise in temperature in the neural retina.


Figure 1. Axi-symmetric eye model


Figure 2. Power distribution for CW and pulsed laser 


Figure 3. Temperature distribution along center line

by zopeown last modified 2015-01-23 14:20