For the sake of historical completeness, and in order to better
emphasize the special domain of iridotomy, I will mention briefly the
various methods that have been employed in making an artificial pupil.
These are:
(1) _Division_ of the thickened iris-membrane by an incision made
either through the sclerotica or through the cornea. This is true
_iridotomy_.
(2) _Excision_ of a portion of the iris through a previously made
corneal opening. This is now known as _iridectomy_.
(3) _Separation_ of the iris from its ciliary attachment. This was
generally known as _iridodialysis_, but sometimes called _iridorrhexis_.
(4) Simple _incision_ of the pupillary margin, and of the free iris
tissue. This has been designated _sphincterotomy_ by some, and
_coretomy_ or _iritomy_ by others. Either one of the latter terms is to
be preferred, because it is more clearly descriptive.
(5) _Detachment_ of the synechiæ at the pupillary margin, either
anterior or posterior, thus allowing the pupil to retract. This was
known as _corelysis_.
(6) _Strangulation_ of the prolapsed iris in the corneal incision was
called _iridencleisis_. The prolapse was sometimes tied with a ligature.
(7) _Trephining_ of the iris-membrane, by passing a small trephine or
punch through a corneal incision.
(8) _Section_ and removal of a portion of the sclerotica and chorioid
by knife or trephine, with replacement of the conjunctiva over this
opening, the conjunctiva thus acting as a substitute for the cornea in
transmitting light. This was called _sclerectomy_.
(9) _Transplantation_ of the cornea for total leucoma. This was usually
preceded by partial or complete trephining of this membrane.
In addition to these nine distinct methods certain combinations of
these have been described and successfully practiced:
(10) _Division_ and _excision_ have frequently been performed together.
(11) _Separation_ and _excision_ have likewise had some vogue.
(12) _Separation_ and _strangulation_ have occasionally been practiced.
(13) _Detachment_ of the synechiæ and _excision_ have also been
performed.