The Effect of Axial Length on Photodynamic Therapy

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• 作者：Siamak Ansari-Shahrezaei ; Erdem Ergun and Michael Stur
• 刊名：American Journal of Ophthalmology
• 出版年：2006
• 出版时间：April 2006
• 年：2006
• 卷：141
• 期：4
• 页码：699
• 全文大小：141 K

文摘

Purpose

To determine the effect of the axial length of the eye on photodynamic therapy (PDT) light fluence.

Design

Laboratory investigation.

Methods

A calibrated Gullstrand-type model eye was used for this study. The axial length of the model eye was set to different values ranging from 20 to 31 mm, and the light fluence rate for treating a spot of 4 mm was recorded and compared with a fluence rate of 600 mW/cm² with four indirect condensing laser lenses.

Results

The axial length of the eye is inversely related to light fluence. From myopia to hyperopia, the total deviation from 600 mW/cm² was −37.7 % to +53.8 % (Mainster Standard; Ocular Instruments Inc, Bellevue, Washington, USA), and −48.3 % to +20.5 % (Mainster Wide Field; Ocular Instruments Inc), −52.3 % to +16.7 % (Volk Transequator; Volk Optical Inc, Mentor, Ohio, USA), and −52.3 % to +15.3 % (Volk PDT Laser; Volk Optical Inc).

Conclusions

Axial length of the eye has a considerable effect on PDT light fluence rate in this model. These findings may be important for optimizing PDT, particularly in eyes with high refractive errors.