Lasers in ophthalmology
These were originally used as coagulators. The
ruby laser was superseded by the argon blue—green laser and then the argon
green-only laser, as the blue light was dangerous both to the operator and to
the patient’s macula. Yellow and red wave lengths are also used and the
doubled frequency YAG (yttrium—aluminium—garnet) laser can be used as a
coagulator with a frequency of 533. The YAG laser was developed together with
extracapsular surgery and is used for capsulotomies, iridotomies and cutting
anterior vitreous bands. In its continuous mode it can be used to treat severe
glaucomas.
Holmium
and erbium lasers have been used to create subconjunctival drainage in glaucoma
and the holmium laser can also be used in lacrimal obstruction during a DCR (dacryocystorhinostomy)
operation. CO2 lasers are used to remove external lesion of the
eyelids and excimer lasers are used for refractive surgery. The diode laser can
be used both as a photocoagulator and for treating the ciliary body in advanced
cases of glaucoma. Lasers combined with phakoemulsification to liquefy the human
lens are being developed. Laser surgery is making rapid advances and no doubt
many new forms of lasers will be developed for use in ophthalmology in the next
few years.