Procedure for Custom Fitting an Ocular Prosthesis
(Following an Enucleation)
here for Procedure for Fitting
Phase I Scleral Trial Shell
For the Acquired
Dysfunctional or Phthisical Globe]
This is the climactic stage for information you will receive
on the Internet prior to the actual fabrication and fitting
of the impression moulded plastic ocular prosthesis.
The web site will now transfer you or your child via the
Contact Us to meet
with the Jahrling team of ocularists.
You should have your itinerary planned as to the mode of
transportation to our office, any arrangement for an overnight
stay (if necessary, for out-of-state or out-of-country) and
the appointment dates for the required three sessions.
In order to allay any fears, anxiety or uneasiness caused
by this upcoming new experience, we will explain the process
in a detailed step by step fashion.
Visit #1 (Estimated Duration: 1½ to 2
At the reception desk, you will be escorted into one of the
fitting room to meet your team of ocularists.
Review: History (Hx) and Diagnosis
(Dx) that lead to the eye loss.
External Evaluation: Check the
eyelids for any sign of superior sulcus depression, and/or
atonal defects in the orbicularis and levator muscles.
(Ability to close the eyelids completely, and elevate the
upper eyelid without the use of the eyebrow.)
Internal Evaluation: The cavity
will be checked for depth of the culs-de-sac (to hold the
prosthesis). The condition of the conjunctiva to see
if there is any adhesions (scar bands) or dehiscence (tears
in the tissue), and to study the eye muscle/implant response
to companion eye movement.
Impression moulding of the cavity begins with a verbal and
visual description of the impression moulding technique and
what it entails. The paraphernalia consists of a series
of fenestrated impression acrylic trays with projecting hollow
stems, a 10cc syringe (no needles), alginate impression material,
distilled water, mixing bowl and spatula.
The impression process begins with a selected acrylic tray
that is inserted under the eyelids (that will fit without
creating any distortion of the lower cul-de-sac), and held
in position by the stem. The alginate and water is
mixed and placed into the syringe for easy injection into
the impression tray. (It has a cool sensation when
the flow fills the cavity.) The mixture sets within
two minutes and the entire tray and impression is removed.
A plaster mold is made of the impression to form a replica
of the cavity. At this stage, hot wax is poured into
the plaster mold to duplicate the flush fit of the alginate
The trial fitting of the wax model will then give indication
of any adjustments and modifications necessary to attain
symmetrical anterior projection of the companion eye and
alignment of the eyelids. Its catoptric image is then
marked for pupil-center with a plastic stem (the same type
stem that is on the apex of the plastic iris-cornea button).
While the working wax model is being trial fitted (at our
Boston office) the second ocularist will be doing the iris
color painting to match the fellow eye. The following
detailed description will give a complete insight on this
art of iris color duplication begins by first observing the
depth of the anterior
chamber and the curvature of the cornea.
These are keys to obtaining a three dimensional lifelike
effect of the painted iris. It also helps in selecting
a proper pupil size for the flat acrylic iris disc.
Materials used in the fabrication of the prosthesis must
be compatible with the medical/dental grade PMMA (polymethylmethacrylate).
Iris color pigments selected are only those finely ground
dry colors that have been checked for their chemical and
physical properties for permanence and stability, thereby,
eliminating any chance of color fading or delamination when
incorporated with a suspension of monomer-polymer liquid
mixture. This acrylic mixture for blending the dry
iris pigments, however, does emit an odor, which requires
an exhaust system near the palette.
Controlled light source is utilized for ideal color matching.
Natural daylight is a variable (time of day and atmospheric
conditions) and it will effect the color matching of the
human iris and its scleral tints. Because of this,
all color matching is done under a specially manufactured
artificial fluorescent lighting that has a color spectrum
of north sky daylight (7,500 Kelvin). In addition to
this controlled light source, all natural and standard fluorescent
and incandescent lighting are blocked out. The surrounding
walls are a flat matte gray to eliminate color reflections.
Upon completion of the flat iris disc painting, it is placed
in an iris-cornea die plate for a polymerization cycle to
obtain a clear acrylic cornea (with an attached stem at its
apex). This will then be incorporated with white plastic
material in a two piece dental stone mold made from the prosthetic
Visit #2 – (Estimated Duration: 45 minutes to
The next laboratory session entails the simulation of the
scleral tints and vascular pattern (white portion of the
eye). This is accomplished by first exposing the embedded
iris-cornea surface to the desired iris diameter. Red
nylon and cotton threads are applied in varying thickness
to create the 'bloodshot' appearance. This is followed
by painting on various tints to simulate the scleral tones.
Upon completion, this phase will require a clear acrylic
overlay (which replaces the amount of white acrylic that
was removed to expose the iris) under a controlled heat and
pressure curing cycle.
Visit #3 – (Estimated Duration: 45 minutes to
The completed ocular prosthesis will be polished and fitted
upon your return. It is during this time period that
the verbal and printed instructions will be given for removal/reinsertion,
and the proper hygiene care
of the eyelids, cavity and plastic ocular prosthesis.
(You may refer to these instructions in the Procedures
We will then schedule a follow-up session for 4 to 6 weeks
later to check for comfort, fit and cosmesis. It is
advisable to make notes of any questions you need answered,
or any wearing problems you may have experienced in the interim.