Influence of laser photocoagulation on choroidal capillary cytoarchitecture

Citation
Rh. Guymer et al., Influence of laser photocoagulation on choroidal capillary cytoarchitecture, BR J OPHTH, 85(1), 2001, pp. 40-46
Citations number
36
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Optalmology,"da verificare
Journal title
BRITISH JOURNAL OF OPHTHALMOLOGY
ISSN journal
0007-1161 → ACNP
Volume
85
Issue
1
Year of publication
2001
Pages
40 - 46
Database
ISI
SICI code
0007-1161(200101)85:1<40:IOLPOC>2.0.ZU;2-A
Abstract
Aim-To identify if laser photocoagulation induces morphological changes spe cifically related to the choroidal capillary endothelial processes that pro trude into Bruch's membrane. Methods-Two human eyes and one adult macaque monkey eye received retinal la ser photocoagulation that was just suprathreshold, before enucleation or ex enteration. They were examined by electron microscopy to determine the leng th of the endothelial processes emanating from the choroidal capillaries in the region around the laser burn. One human and two monkey untreated eyes were used for comparison. Results-In human eyes, there was no increase in the number of processes 15 hours after laser treatment but at 5 days the processes were more numerous and longer within 400-500 mum of the burn than in the untreated half of the same eye. The processes were longer 9 days after photocoagulation in the m onkey, when compared with untreated monkeys, and some breached the elastic lamina, a phenomenon not seen in the untreated eyes. Qualitative difference s were also noted in the endothelial cell processes following photocoagulat ion. Neovascularisation was not observed. Conclusions-Protrusion of choroidal endothelial cell processes into Bruch's membrane is a normal anatomical feature but the number, length, and morpho logy of the processes change following mild photocoagulation. It is plausib le that these processes may play a part in the clearance of debris from Bru ch's membrane, and represent an early stage of angiogenesis. If the latter is true prophylactic laser photocoagulation at just suprathreshold levels m ay carry a risk of inducing choroidal neovascularisation.