In vitro videographic comparison of argon and Nd:YAG laser iridotomy.
We used an in vitro technique with high-magnification video recording to evaluate from the posterior side of the iris the immediate sequence of events during argon and Nd:YAG laser peripheral iridotomy. The observed effects differed strikingly. The argon laser caused a gradual mounding up of iris pigment epithelium with each successive energy application before final penetration. This effect was reduced but not eliminated with higher power levels. The Nd:YAG laser caused complete disruption and dispersal of the pigment epithelium with a single pulse of energy. Additionally, a multiple focal point configuration of the Nd:YAG laser was observed to produce a significantly larger iridotomy than a single focal point configuration for comparable energy settings. These observations may in part explain the observed clinical advantage of the Nd:YAG laser over the argon laser for creation of a patent iridotomy.
Prum
B E
BE
Department of Ophthalmology, Duke University Eye Center, Durham, North Carolina 27710.
Shields
S R
SR
Shields
M B
MB
Hickingbotham
D
D
Chandler
D B
DB
D006801:Humans; D007498:Iris / Q000473:pathology / Q000601:surgery*; D053685:Laser Therapy; D010857:Pigment Epithelium of Eye / Q000473:pathology / Q000601:surgery; D014741:Video Recording