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& Potential Complications
Cataract surgery and lens implant
Laser photocoagulation of retinal tears and vascular disease
Vitrectomy for diabetes, macular hole and epiretinal membranes
Retinal detachment surgery
Dislocated intraocular lens cataract surgery
Bleeding (Intraocular hemorrhage) intraocular hemorrhage
Endophthalmitis (Infection) endophthalmitis
Extruding scleral buckle scleral buckle
Retinal incarceration scleral buckle
Disruption of the anterior vitreous face “vitreous loss” predisposes
the eye to develop cystoid macular edema and retinal detachment,
especially if vitreous strands adhere to the iris and wound.
Insertion of the intraocular lens into the pre-existing lens capsular
bag is preferred.
If the lens capsule fractures during surgery, the natural lens may drop
into the vitreous cavity. A dropped or retained lens causes
inflammation and glaucoma and may require a vitrectomy to restore
The intraocular lens may become dislocated. The lens capsule of
the eye is fixed to the wall of the eye with fine fibers called
zonules. Age, manipulation at the time of surgery, and some
conditions such as the pseudo-exfoliation syndrome, may weaken the
zonules and so permit the lens capsule to stray from is appropriate
location. The dislocated lens may fall into the vitreous, where
vitrectomy techniques with intraocular forceps are used to retrieve and
reposition the lens.
The overwhelming majority of procedures to remove a cataract and insert
an intraocular lens go without complication. When a plastic or
silicone lens comes in contact with the internal surface of the cornea,
the corneal endothelial layer is injured. With excessive damage,
at the time of surgery or post-implantation, the cornea may fail
(corneal decompensation) to maintain sufficient transparency.
An office-based treatment for a peripheral superior retinal tear and
detachment, primarily used in patients who possess their natural lenses
(phakic). After the tear is treated through external cryopexy, an
expansile gas is injected through the pars plana. The gas expands
and the patient and eye are positioned so the gas bubble presses
against the tear, to seal the tear against the wall of the eye.
The retinal pigment epithelium pumps out the residual sub-retinal
fluid. A chorio-retinal bond becomes secure after several
days. The failure rate for pneumatic retinopexy is about 1 in 7 –
necessitating a second procedure such as a scleral buckle, a vitrectomy
Retinal laser is usually applied with a highly modified slit lamp with
the patient and physician seated at a console. Occasionally the
beam is delivered with an indirect ophthalmoscope. Focal and grid
applications for diabetes are performed with low energy and are
painless. Eye drops provide topical anesthesia. The eyelids
are kept apart by a contact lens. Extensive treatment for
proliferative diabetic retinopathy and lattice degeneration may be
painful and necessitate injection of local anesthetic into the eyelids
Retinal laser is applied in a focal or scatter array. It serves
to seal leaking blood vessels, destroy ischemic retina or burn the RPE
to create a scar. The greatest risk is a laser is a miss-hit to
the center of the macula (fixation). Tolerances are close: many
diabetic lesions are only 200 microns (1/5th of a millimeter) from
fixation. If the burn is too intense, there may be lateral heat
spread and collateral retinal damage and too much damage to the RPE
setting the stage for choroidal neovascularization and scarring.
Collateral retinal damage may become manifest months to years after the
laser application. Heavy scatter peripheral laser may impair
peripheral vision and visual field and lead to complaints of night
The most modern lasers (Pascal) can fire many spots simultaneously to
speed therapy and lessen discomfort.
Scleral buckling, an operative procedure, and the technique of choice
for phakic retinal detachments, is about twice as effective and
pneumatic retinopexy. A silicone element is sutured or secured to
the external surface of the sclera and indents the wall of the eye to
reduce traction at the site of a retinal tear. The tear is sealed
with laser or cryopexy. Failure of primary repair for retinal
detachment is expected in 10% of procedures. Retinal detachment
repairs fail because the tear is not closed, there is an unrecognized
tear or proliferative vitreoretinopathy.
In many cases, especially with excessive subretinal fluid, the sclera
is punctured with a fine instrument or heated needle, to provide a
pathway for the escape of the subretinal fluid. Attempts to drain
subretinal fluid occasionally lead to subretinal bleeding,
incarceration of retina into the drain site and choroidal
hemorrhage. These are major complications and reduce the
likelihood of a success in regard to both visual acuity and the overall
rate of reattaching the retina to its original position.
Cryopexy may have a greater potential than laser to induce macular
pucker, and proliferative vitreoretinopathy.
In 5-10% of scleral buckle procedures, the synthetic elements sutured
or otherwise attached to the wall of the eye will break through the
conjunctival covering of the globe and become exposed. This
produces discomfort, a “foreign body” sensation and a potential site
for infection. The extruding elements are removed – and
infrequently, the retina may re-detach.
In the standard (3-port) techniques, three incisions are made into the
pars plana region to accommodate a light, a suction/cutter and a port
for the infusion of a salt solution. Specialized light and cutter
vitrectomy tools may have multifunction capability to scrape, cut, burn
or grasp. Some surgeons use small gauge instrumentation and
suture-less closure – but risk higher rates of infection and hypotony
if the wounds fail to seal tightly.
When retinal tears or detachment is present, the fluid in the eye is
replaced by a vitreous substitute, such as air, an expansile gas or
silicone oil. The vitreous substitute as a temporary or
long-lasting splint – to keep the retina in position while a local
adhesion develops. Heavy liquid silicone may be used at the time
of surgery or for short periods to press the posterior retina or
inferior retina into place.
Cataract is frequent after vitrectomy, especially if the lens has been
directly contused, and may happen in 50% of cases involving peels for
macular pucker. Instrumentation through the pars plana is in
close proximity to the peripheral retina and may occasionally cause a
peripheral tear and detachment. Maneuvers close or on the retinal
may produce tears or retinal contusions.
Possible risks of vitrectomy surgery include the development of new
retinal tears or detachment, intraocular bleeding and rarely, infection
Endophthalmitis – intraocular infection occurs in 1/500 to 1/5000
procedures. Bacteria on the ocular surface (or more rarely in the
bloodstream) enter the eye and proliferate to the detriment of the
retina and other internal structures. Pain and loss of vision
herald the infection, usually after two or more days after an invasive
procedure. Prompt reecognition of the condition and the
administration of intraocular antibiotics may salvage the eye and
vision in some cases.
Intraocular hemorrhage – May develop in a variety of invasive
procedures. When instruments are introduced into the eye, the
intraocular pressure falls and vessels in the retina and uvea may bleed
– spilling blood into the vitreous (vitreous hemorrhage) or choroid
(choroidal hemorrhage). Neovascular complexes on the retina and
iris are at high risk for bleeding, especially with ocular
hypotension. Choroidal hemorrhage is notorious in high myopes
undergoing scleral buckling. Excessive manipulation or surgical
trauma to the retina and/or uvea may be responsible for vitreous
hemorrhage in some cases. In a substantial number of vitrectomies
for vitreous hemorrhage, peripheral vitreous hemorrhage cannot be
completely evacuated, necessitating a second procedure or prolonged
recovery as blood is slowly reabsorbed.