Effect of axial length on laser spot size during photodynamic therapy: an experimental study in monkeys.
OBJECTIVE
To investigate the effect of shorter axial length on the laser spot size and laser energy during photodynamic therapy (PDT) in monkeys.


METHODS
Experimental study with four rhesus monkeys.


METHODS
PDT was performed on the normal retina of monkeys whose ocular axial lengths are shorter (19.55 to 20.25 mm) than that of humans. After the PDT, the eyes were enucleated, and the diameter of the irradiated laser spot was measured with a microcaliper.


RESULTS
The area of actual laser spot was only 0.56 to 0.61 times of the planned area, which indicated that the laser energy/area was 1.64 to 1.78 times more intense than planned initially.


CONCLUSIONS
These results are the in vivo demonstration that the diameter of PDT laser spot is smaller for eyes with shorter axial lengths.
Kondo
Mineo
M
Department of Ophthalmology, Nagoya University School of Medicine, 65 Tsuruma-cho, Showa-ku, Nagoya 466-8550, Japan. kondomi@med.nagoya-u.ac.jp
Ito
Yasuki
Y
Miyata
Kentaro
K
Kondo
Nagako
N
Ishikawa
Kohei
K
Terasaki
Hiroko
H
D000818:Animals; D000886:Anthropometry; D005123:Eye / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D007834:Lasers / Q000009:adverse effects*; D008253:Macaca mulatta; D010778:Photochemotherapy; D017319:Photosensitizing Agents / Q000008:administration & dosage; D011166:Porphyrins / Q000008:administration & dosage; D012160:Retina / Q000293:injuries* / Q000473:pathology; D014463:Ultrasonography; D000077362:Verteporfin
D017319:Photosensitizing Agents; D011166:Porphyrins; D000077362:Verteporfin