Download Where anterior segment and posterior segment surgery meet

Retina
6th EURETINA Congress
Symposium Report
Gisbert Richard
Peter Barry
Roibeard O’hEineachain
in Lisbon
THIS year’s EURETINA meeting included a
joint EURETINA/ESCRS symposium on
where anterior segment and posterior
segment surgery meet.
Commencing the session, co-chairman,
Gisbert Richard MD, University Medical
Centre Hamburg-Eppendorf, described a
combined surgery procedure for cataract
patients who require pars plana vitrectomy
(PPV) for such indications as epiretinal
membranes, macular holes and diabetic
retinopathy.
He noted that PPV can induce cataract
and a progressive myopisation in a high
proportion of patients. Combining PPV with
cataract surgery can eliminate those
problems. However, the two procedures
have contradictory requirements. PPV
requires a closed system that will tolerate
an increased IOP whereas cataract surgery
requires opening of the eye, he said.
To meet the conflicting requirements of
the PPV and cataract surgery, Dr Richard
has adopted a combined approach that
employs a long corneoscleral tunnel.The
procedure commences with the fixation of
two eye muscles and the precise creation
of a corneoscleral tunnel at least 3.5mm in
length through which both PPV and
cataract extraction are performed.
“A combined approach using a
corneoscleral tunnel tolerates the pressure
increase while at the same time allowing an
opening large enough for cataract surgery,”
he said.
Results similar to sequential approach
Dr Richard presented his results using the
combination technique in a wide range of
indications His findings suggest the
technique can achieve visual outcome
comparable to non-combined surgery.
He noted that in a consecutive series of
230 patients with epiretinal membranes
visual acuity improved postoperatively in
82% of eyes, remained unchanged in 7% and
became worse in 11%. Complications
included posterior synechiae in four eyes.
In 130 eyes with macular holes the
combined procedure brought about
macular hole closure in 86% of eyes and an
improvement of two lines or more in visual
acuity in 75%.There were no problems with
peeling the internal limiting membrane, he
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Where anterior segment and posterior
segment surgery meet
added. Complications included a temporary
increase in IOP in 16%, an increase in
astigmatism in two per cent, and retinal
detachment in four per cent.
In 140 eyes that underwent the
combined approach for retinal detachment
due to diabetic retinopathy, the retina was
successfully re-attached in 90% of eyes and
visual acuity improved in 73%.
However, residual peripheral detachment
was present in 10% of eyes; posterior
synechiae occurred in 13%; vitreous
haemorrhage occurred in 10%; and iris
capture in three per cent.There was also an
increased incidence of secondary cataract
formation.
“Opening of the anterior chamber via a
corneoscleral tunnel meets the
contradictory requirements of anterior and
posterior segment surgery, making
combined surgery safe and efficient
provided there are no severe disturbances
of the blood-retinal barrier.”
IOL luxation into the vitreous
Dr Richard’s associate Oliver Zeitz MD
followed with his insights into the
management of IOL luxation.
Estimates of the incidence of IOL
luxation range from around 0.2% to 1.8%,
Dr Zeitz noted. Approximately 60% of
luxations occur in the first two weeks after
cataract surgery. The complication occurs
more commonly in IOLs with a plate haptic
design and can result from defects of the
posterior capsule or zonular fibres,YAG
capsulotomy, and trauma.
The time to surgery does not appear to
influence visual acuity outcome, therefore
simple observation is one option to
consider, he pointed out. However, possible
complications of luxated IOLs include
decreased vision, glare, iritis, secondary
glaucoma, retinal detachment and cystoid
macular oedema.
On the other hand, surgery also carries a
fairly significant risk of cystoid macular
oedema, retinal detachment and secondary
glaucoma. Other less common
complications of surgery include diplopia,
pigmented disciform scar and vitreous
haemorrhage, he noted.
“There is no strong need to perform
surgery, but if you decide to do it, do it
completely and without any compromise,”
he added.
Repositioning or removal
Surgical options include re-positioning the
lens or removing and replacing it, with or
without PPV, he said.
Repositioning the IOL has the advantage
of being less invasive and having a lower
rate of complications. However, repositioning of the luxated IOL also carries a
higher risk of recurrence due to insufficient
fixation of the repositioned lens. IOL
removal and replacement is called for in
cases where the IOL has been damaged or
it has an incorrect refractive power.
In many cases PPV is not required for
repositioning and even removal and
replacement of a luxated IOL. PPV becomes
necessary if the IOL is luxated deeply into
the posterior segment or if substantial
amounts of vitreous envelope the IOL.
Dislocated IOLs can be mobilised by
intraocular forceps or other instruments or
through elevation in the vitreous cave by the
injection of heavy fluids. IOLs can be
removed through a limbal or scleral pars
plana incision. Dr Zeitz recommended a
limbal approach since it is less likely to result
in complications.
Means of restoring good visual acuity in
eyes where the IOL has been removed
include contact lenses, retropupillary irisclaw anterior chamber IOLs, scleral-fixated
lens and, if a substantial amount of the
capsule remains, posterior chamber IOLs.
“Visual acuity outcome is equivalent for all
visual rehabilitation approaches.The major
limiting factors are co-existing ocular
pathologies,” he said.
The dropped lens
Peter Barry FRCS, Dublin, Ireland, discussed
strategies for dealing with the dropped lens.
“I think all of us have had the experience
of dropping a nucleus whilst performing
cataract surgery.You all know the sense of
despair; you panic and feel somewhat
embarrassed.You hope that nobody will
really notice what’s happening. But then you
actually realise that you’ve made a mistake,
you’ve got a problem, and you have to face
up to it.”
Possible consequences of such events
include corneal failure, uveitis, glaucoma,
vitritis, cystoid macular oedema, and retinal
detachment.The challenge for the surgeon is
to avoid those complications and remove
the dropped lens and implant an IOL in the
capsular bag, Dr Barry said.
Experienced cataract surgeons can achieve
this by first performing a closed anterior
vitrectomy, aspirating the soft lens material
while at the same time being very careful to
preserve capsular remnants.
“Less experienced surgeons are
sometimes in a hurry to complete this part
of the procedure but it should really be the
other way around: slow down, do your
anterior vitrectomy and tease out the
residual lens cortex with very low infusion
and ensure that you preserve the capsular
bag remnants in order to achieve lens
implantation.”
Vitreoretinal surgeons can use the
alternative technique of pars plana
vitrectomy, again aspirating the soft lens
material, using a fragmatome in denser
cataracts.The use of viscoelastics should be
avoided with this approach because it is
difficult to remove following vitrectomy.
With both approaches a posterior
chamber IOL can usually be successfully
implanted although sometimes it will need to
be implanted in the sulcus, Dr Barry added.
Effects of cataract surgery on the
macula
Conceição Lobo MD, Coimbra, Portugal
discussed the effects of cataract surgery on
the macula. She noted that angiographic
CME occurs in about 20% of eyes
undergoing such procedures, although it
becomes symptomatic in only around 1-2%.
Dr Lobo recommended mapping of the
macula with a multimodal approach to
characterise the condition’s features and
assess treatment in patients in whom it
affects vision.
She presented a study in which she and
her associates used multimodal macular
mapping in 32 patients who had undergone
phacoemulsification and IOL implantation.
The approach involved a combination and
integration of fluorescein angiography, Retinal
Leakage Analysis (RLA) Retinal Thickness
Analysis (RTA/OCT).
The study showed that leakage reached its
maximum at 12 weeks and was present in
88%. Retinal thickness peaked at six weeks,
when it was increased in 41%. By 30 weeks
leakage was present in only 68% and retinal
thickness was increased in only 28%.Visual
acuity followed a similar pattern.That is,
visual acuity of 8/10 or better was achieved
by 81% at three weeks, 88% at 12 weeks and
91% at 30 weeks.
Prevention of PCO
Dr Marie-José Tassignon MD, University
Hospital Antwerp, Belgium, followed with a
presentation describing the latest results with
the bag-in-the-lens IOL.The lens is specifically
designed to prevent posterior capsule
opacification.
Patients who are to be implanted with the
lens first undergo anterior and posterior
capsulorhexis, Dr Tassignon explained.The
rims of the IOL’s specially designed haptics
clasp the edges of the remaining capsular bag
together. In this way the lens prevents lens
epithelial cell migration and PCO. In addition,
the anterior and posterior haptics are
oriented perpendicularly to each other in
order to prevent the tilting, rotation or
decentration of the lens.
Dr Tassignon has implanted the IOLs in
over 600 eyes, 25 of which were paediatric
cases. She noted that in all eyes with a
follow-up of at least one year the optic
portion of the lens has remained clear and
none have required a YAG capsulotomy.
Furthermore, in a study which compared
the results of implantation of the bag-in-the
lens IOL in 100 patients and 100 patients
implanted with a conventional IOL made of
the same hydrophilic acrylic material, none of
the eyes with the bag-in-the-lens IOL
required YAG laser capsulotomy after a
follow-up of four years, compared to YAG
capsulotomy rate of 41.18% in the
conventional IOL group.
“The results make it 100% clear that with
the bag-in-the lens IOL you have no PCO
whatsoever.”
To further optimise the placement of the
IOL, Dr Tassignon has designed a ring-shaped
calliper to guide the surgeon in the creation
of the anterior
capsulorhexis.The
more precise
centration and sizing
of the capsulorhexis
that the device
affords may in turn
improve the stability
of the IOL.
“When IOL
rotation and
centration is under
control spherical
aberration and toric
correction can be
introduced,” she
added.
A version of the
Three years after implantation, no opacification of the central area can be seen
lens in which the
optic can be
light perception or better vitrectomy
exchanged in subsequent procedures is now
produces better results.
under development.The new lens could be of
The EVS also showed that intravitreal
particular benefit to paediatric patients.
antibiotics
such as vancomycin and amikacin
Future modifications of the lens may make it
were effective in bringing about a resolution
possible for patients to achieve a degree of
of the condition.Another finding was that the
accommodation, Dr Tassignon said.
systemic intravenous antibiotics used in the
study (cephalosporins and aminoglycosides)
Treatment of endophthalmitis
produced no apparent benefit.
William F Mieler MD, University of Chicago,
However, recent studies suggest that
Chicago, Illinois, US, discussed the current
newer, fourth generation fluoroquinolones
thinking on the treatment of endophthalmitis.
such as gatifloxacin and moxifloxacin may be
“This field is rapidly changing and there are
effective in the treatment of endophthalmitis
many questions that remain unanswered at
when administered orally, Dr Mieler pointed
this point in time as to our true best
out.
management.We like to recommend
“These are agents that penetrate inside
treatment based on evidence-based medicine
the eye very readily when given orally even in
but in some cases we don’t have all the
non-inflamed eyes,” he added.
answers.”
In a study involving patients undergoing
He noted that the Endophthalmitis
elective vitrectomy, oral administration of
Vitrectomy Study (EVS) showed that vitreous
gatifloxacin achieved a maximum vitreous
tap and vitrectomy had equivalent results
penetration that exceeded the MIC90 for all
when the affected patient had hand
the Gram-positive microorganisms except
movements or better. If the patient’s vision is
enterococcus.The agent also achieved the
Courtesy of Marie-José Tassignon MD
Retina
MIC90 levels for most of the Gram-negative
organisms except pseudomonas.
Gatifloxacin was recently withdrawn from
the market as an oral agent due to its
adverse effect on blood-sugar control.
However, it is still available for topical use as
eye drops.
Moxifloxacin, which is still on the market
for oral use, provides an even better
spectrum of control and achieves a
concentration in the vitreous cavity that is
38% of that of serum concentration. In
addition the agent appears to be safe in the
eye at concentrations 500 times as high as
the MIC90 for the most commonly
encountered microorganisms.
“Exciting significant advances have been
made in the treatment of proven infection,
and in the prophylaxis against development of
infection. Numerous additional changes are
forthcoming,” he commented.
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