Castellarin and colleagues [1] recount their recent experience of
infusing silicone oil in a small series of patients with advanced diabetic
eye disease, either during primary vitrectomy (12 eyes) or after earlier
surgery had failed (11 eyes). They compare their results with previous
reports and conclude that silicone oil remains a useful adjunct in
diabetic vitrectomy. However, their conclusions and h...
Castellarin and colleagues [1] recount their recent experience of
infusing silicone oil in a small series of patients with advanced diabetic
eye disease, either during primary vitrectomy (12 eyes) or after earlier
surgery had failed (11 eyes). They compare their results with previous
reports and conclude that silicone oil remains a useful adjunct in
diabetic vitrectomy. However, their conclusions and historical
comparisons are open to question.
Silicone oil was first used in primary diabetic vitrectomy in an era (1979-84) before the introduction of endolaser and the Landers' double concave lens for phakic fluid: air exchange.[2-4] Dealing with large or
multiple posteriorly-located breaks (whether pre-existing or iatrogenic)
was problematic, and direct fluid:silicone oil exchange (by virtue of the
optical advantages of oil over air in the phakic eye) provided a surgical
escape route, obviating the need for lensectomy. Furthermore, the clarity
of the media immediately postoperatively facilitated the slit-lamp
delivery of focal laser in order to seal retinal breaks that had been
closed by the internal tamponade, and in addition the application of
scatter laser to re-attached, untreated, ischaemic retina that had
undergone deturgescence, in part through the 'waterproofing' effect of
silicone oil.[3,4] All being well, the silicone oil could then be
removed shortly thereafter, and some eyes that would undoubtedly have been lost were saved by the intervention of silicone oil in this
way. Often, however, there were considerable associated problems, not
least the rapid development of reparative epiretinal fibrosis whereby the
retina re-detached under tangential traction and/or from re-opening of
retinal breaks.[2-6] Sometimes huge areas of retinal disintegration
eventually developed.[5,7] The fibroglial epiretinal proliferation
appeared (both clinically and pathologically) to be particularly induced
by clotted blood trapped between the silicone oil and the retinal surface
or, ironically, by fibrin released as a result of the extensive scatter
laser that was often needed to prevent highly vascularised membranes from
re-proliferating behind the silicone oil.[4,5,8,9]
It was hoped that the so-called 'compartmentalisation' of the eye by
silicone oil (to which the retro-silicone oil neovascularisation was
attributed) might in turn result in prevention or reversal of rubeosis
iridis through its putative barrier effect against anterior diffusion of
angiogenic substances derived from the ischaemic retina.[3-8]
Paradoxically, eyes with successful retinal reattachment (albeit with
unabated ischaemia) often underwent rapid development or progression of
iris neovascularisation,[3,8] while those with failed surgery from
postoperative rhegmatogenous recurrence of retinal detachment (and
therefore eyes with an exaggerated angiogenic drive) had evidence of
protection from rubeotic phthisis, at least in the short term.[3]
Perhaps naively it was postulated that rhegmatogenous confinement of the
re-detachment by intravitreal silicone oil (and the consequent 100% oil
filling of the shrinking vitreous cavity) might allow an effective
obstruction to anterior molecular diffusion to be established in these failed cases.[3] Others had planned from the outset to employ silicone oil in their
surgical protocol, not least for those diabetic eyes wherein earlier
vitrectomy had been unsuccessful as a consequence of retinal re-detachment [4,10,11] or recurrent vitreous cavity haemorrhages.[4] However, whether
used during primary diabetic vitrectomy or secondarily, whether
unpremeditated or planned, and whether infused by direct fluid:oil
exchange or sequential fluid:air and air:oil exchanges, the possibility
of silicone oil limiting rubeosis and maintaining macular attachment
despite peripheral retinal re-detachment was always welcome, even if
surgical 'success' (that is, retinal attachment through 360 degrees) had
strictly been denied.[2-4,8,12]
Nowadays, posterior retinal breaks and retinectomies can generally be
managed successfully by employing wide-angle viewing systems, heavy
liquids, endolaser, and long-acting gases. However, silicone oil continues
to be infused during diabetic vitrectomy despite the attendant posterior
segment and anterior segment complications that have only been partially
mitigated by the improved quality of the silicone oil. The important
question that thus arises is: what is the appropriate use of silicone oil
in the diabetic eye in the modern era? Where retinal breaks might be
closed just as readily using gas tamponade, or where rubeosis iridis might
be reversed or prevented by retinal reattachment and/or a sufficiency of
scatter laser photocoagulation, the use of silicone oil might be described
fairly as 'gratuitous'. Exceptions might include anticipated posturing
difficulties [3] or the need for early visual rehabilitation in one-eyed
patients.[4] However, recent reports documenting the use of silicone oil in diabetic vitrectomy have failed to
provide clear criteria or explanations regarding case selection.[1,12,13]
Only 7 of the 23 eyes in Castellarin and colleagues' series, for example,
had retinal breaks (2 pre-existing, 4 iatrogenic and 1 retinectomy), so
the need for prolonged internal break tamponade was presumably not an
issue in the majority of their eyes. More information is needed on the
rationale for silicone oil infusion (not just the overall indications for
surgery) in the remaining eyes in order to enable the potential benefits
of this surgical adjunct to be assessed at this time. Furthemore,
surgical success can really only be judged after a minimum of six months
from the last vitreoretinal procedure,[3,4,8,10-12] and that judgement
should preferably include consideration of whether the silicone oil has
been removed and the status of the fellow eye.[14] The fact that 10 of
the 23 eyes in Castellarins series were followed for only one or two months was thus a further serious limitation of their
study.[1]
Infusion of silicone oil can be a most beguiling option during the
closed microsurgical management of the stricken diabetic eye but, as
mentioned, complications are prone to accumulate with time.
Distinguishing the gratuitous from the virtuous use of silicone oil can be
problematic, and equally it may be difficult to define the line between a
surgeon's infusing silicone oil in anticipation of eventual surgical
failure and such infusion representing his/her unstated admission that
surgical failure has occurred already. All these issues need to born in
mind when making historical comparisons between case series and in
defining the place in history for silicone oil in diabetic vitrectomy.
References
(1) Castellarin A, Grigorian R, Bhagat N, et al. Vitrectomy with
silicone oil infusion in severe diabetic retinopathy. Br J Ophthalmol
2003; 87: 318-21.
(2) Lean JS, Leaver PK, Cooling RJ, McLeod D. Management of complex
retinal detachments by vitrectomy and fluid/silicone exchange. Trans
Ophthalmol Soc UK 1982;102: 203-5.
(3) McLeod D. Silicone-oil injection during closed microsurgery for
diabetic traction retinal detachment. Graefe's Arch Clin Exp Ophthalmol
1986; 224:55-9.
(4) Lucke KH, Foerster MH, Laqua H. Long-term results of vitrectomy
and silicone oil in 500 cases of complicated retinal detachment. Am J
Ophthalmol 1987; 104: 624-33.
(5) Barry PJ, Hiscott PS, Grierson I, et al. Reparative epiretinal
fibrosis after diabetic vitrectomy. Trans Ophthal Soc UK 1985; 104: 285-
96.
(6) Charles S. Vitreous surgery, 2nd edition Baltimore: Williams and Wilkins, 1987. Pp 115-31.
(7) Wilson-Holt N, Gregor Z. Spontaneous relieving retinotomies in
diabetic silicone filled eyes. Eye 1992; 6: 461-4.
(8) Yeo JH, Glaser BM, Michels RG. Silicone oil in the treatment of
complicated retinal detachments. Ophthalmology 1987; 94: 1109-113.
(9) McLeod D, James CR. Viscodelamination at the vitreoretinal
juncture in severe diabetic eye disease. Br J Ophthalmol 1988; 72: 413-9.
(10) Rinkoff JS, de Juan E, McCuen BW II. Silicone oil for retinal
detachment with advanced proliferative vitreoretinopathy following failed
vitrectomy for proliferative diabetic retinopathy. Am J Ophthalmol 1986;
101: 181-6.
(11) Brourman ND, Blumenkranz MS, Cox MS, Trese MT. Silicone oil for
the treatment of severe proliferative diabetic retinopathy. Ophthalmology
1989; 96
: 759-64.
(12) Azen SP, Scott IU, Flynn HW Jnr, et al. Silicone oil in the
repair of complex retinal detachments. A prospective observational
multicenter study. Ophthalmology 1998;105: 1587-97.
(13) Scott IU, Flynn HW Jnr, Lai M-Y, Chang S, Azen SP. First
operation anatomic success and other predictors of postoperative vision
after complex retinal detachment repair with vitrectomy and silicone oil
tamponade. Am J Ophthalmol 2000; 130: 745-50.
(14) McLeod D. Microsurgical management of neovascularisation
secondary to posterior segment ischaemia. Eye 1991; 5: 252-9.
We read with interest the article by Dr Li and colleagues about
trypan blue staining of the vitreomacular interface during vitrectomy [1]
We congratulate the authors on their work. In particular, we appreciate
their critical approach of testing trypan blue for staining of the
internal limiting membrane (ILM) and epiretinal membrane (ERM) as well
as
their comments on potential untowards effect...
We read with interest the article by Dr Li and colleagues about
trypan blue staining of the vitreomacular interface during vitrectomy [1]
We congratulate the authors on their work. In particular, we appreciate
their critical approach of testing trypan blue for staining of the
internal limiting membrane (ILM) and epiretinal membrane (ERM) as well
as
their comments on potential untowards effects of indocyanine green (ICG) in macular surgery. We would like to comment on two remarks concerning
the
ultrastructural findings on the retinal side of the ILM following ILM-
removal with and without the use of ICG.
We agree with Dr Li and collegues that fragments of glial cells are
commonly found in ILM-specimens. Ultrastructurally, they appear as tiny
fragments of Müller cell membranes adherent to and enclosed within the
undulations of the retinal side of the ILM. These glial structures had
been described in detail by Eckhardt and collegues, and are in
accordance
with previous work of our group, in an investigation of the
ultrastructure
of the vitreomacular interface of 93 specimens in 91 consecutive
patients
with macular holes, epiretinal membranes, diffuse diabetic macular
edema,
and vitreomacular traction syndrome without the use of indocyanine green
or other dyes (unpublished data).[2]
We also agree with the authors, that the surgical technique and the
underlying disease may influence the amount of glial structures adherent
to the retinal side of the ILM, as these structures are predominantly
found within undulations and folds of the ILM.[3,4] However, we would like to emphasize the effect of ICG in this context.
Firstly, there are obvious differences between ILM specimens removed
with
and without the use of ICG not only in terms of quantity of glial
structures but in terms of quality. A continuous layer of cell
membranes,
undetermined cellular debris, and entire footplates of Müller cells were
commonly observed following ICG-assisted peeling of the ILM, whereas
such
structures had never been found in the series of 93 unstained specimens
described above.[5]
Secondly, all stained and unstained specimens having been investigated
by
electron microscopy were removed by one experienced surgeon (A.K.).
Beside
the use of ICG, there was no change of the surgical technique. Moreover,
retinal elements as described above were not found before the
introduction
of the dye at our institution in September 2000, nor after having
stopped
ICG-staining in April 2001.
Thirdly, in an experimental setting in human donor eyes published
recently, retinal structures adherent to the undulating side of the ILM
as
described above could be found following the application of ICG to the
macula only.5 No attempt of peeling or any other mechanical approach to
the vitreomacular interface was made in these eyes. However, the ILM was
detached from the macula. Retinal elements were adherent to the retinal
side of the ILM showing an identical morphology like those obtained
during
vitrectomy with ICG-assisted ILM-removal.[6]
Therefore, in our experience, there is increasing evidence that at least
some commonly used preparations of ICG may affect the ultrastructure of
the inner retina, and are primarily responsible for obvious differences
in
the ultrastructure of the surgically removed ILM. ILM-removal by itself
results in removal of tiny fragments of Müller cell membranes. Their
morphological and functional implications to the macula remain unknown.
Finally, we would like to encourage the authors to follow-on their
promising approach of staining the ILM and ERM with trypan blue. In our
institution, single specimens which had been stained and peeled using
trypan blue revealed no evidence of retinal damage (submitted data).
References
(1) K Li, D Wong, P Hiscott, P Stanga, C Groenewald, and J McGalliard. Trypan blue staining of internal limiting membrane and epiretinal membrane during vitrectomy: visual results and histopathological
findings. Br J Ophthalmol 2003;87:216-219.
(2) Eckardt C, Eckardt U, Groos S, Luciano L, Reale E.
[Removal of
the internal limiting membrane in macular holes. Clinical and
morphological findings]. Ophthalmologe 1997;94:545-51.
(3) Haritoglou C, Gandorfer A, Gass CA, Kampik A.
Ultrastructure of
epiretinal tissue removed during indocyanine green assisted peeling in
macular pucker surgery [ARVO Abstract No 3516]. Invest Ophthalmol
Vis Sci
2002.
(4) Haritoglou C, Gandorfer A, Gass CA, Schaumberger M,
Ulbig M,
Kampik A. Indocyanine green-assisted peeling of the internal limiting
membrane in macular hole surgery affects visual outcome: a
clinicopathologic correlation. Am J Ophthalmol 2002;134:836-41.
(5) Gandorfer A, Haritoglou C, Gass CA, Ulbig MW, Kampik A.
Indocyanine green-assisted peeling of the internal limiting membrane may
cause retinal damage. Am J Ophthalmol 2001;132:431-3.
(6) Gandorfer A, Haritoglou C, Gandorfer A, Kampik A.
Retinal damage
from indocyanine green in experimental macular surgery.
Invest Ophthalmol Vis Sci 2003;44:316-23.
I read with interest the editorial by Dr DF Chang on SBCS and find myself in agreement with many of his points raised.
A note of caution however. Several years ago when I had converted to topical clear cornea phako I started to perform SBCS on patients I felt required this and were suitable. As I saw the benefits for both the patients and the staff I decided to extend this to the majority of my patients....
I read with interest the editorial by Dr DF Chang on SBCS and find myself in agreement with many of his points raised.
A note of caution however. Several years ago when I had converted to topical clear cornea phako I started to perform SBCS on patients I felt required this and were suitable. As I saw the benefits for both the patients and the staff I decided to extend this to the majority of my patients. I was quickly stopped in my tracks when we discovered that
SBCS is classified and reimbursed to our NHS hospital as a single procedure.
This is even if the patients is listed as two separate procedures. Our hospital could obviously not afford to "reduce" my operating list from 10 cataracts to 5 and at the same time use 10 sets of equipment and 10 IOLs etc every list.
Therefore in the NHS one would have to very careful before embarking on
SBCS until the purchasers or PCGT or whatever they will become in
Foundation Status agree that it is more than a single procedure.
I know DF Chang is relating his practice in the USA but after all the
BJO
is mainly about the practice of Ophthalmology this side of the Pond!
Dr Johansson's thorough and well-written article concerning 'same day' bilateral cataract surgery brought home keen memories and stirred up thoughts of my own experience with this approach to certain patients legally blind due to cataracts.
Periodically from 1951 through 1968, I was the Eye Surgeon-in-Charge of the then modern one hundred bed Kurji
(Patna, Bihar, India) Holy Family Hospital Eye Cli...
Dr Johansson's thorough and well-written article concerning 'same day' bilateral cataract surgery brought home keen memories and stirred up thoughts of my own experience with this approach to certain patients legally blind due to cataracts.
Periodically from 1951 through 1968, I was the Eye Surgeon-in-Charge of the then modern one hundred bed Kurji
(Patna, Bihar, India) Holy Family Hospital Eye Clinic and Eye Hospital on the banks of the Ganges - 350 miles northwest of Calcutta. During the 1951 through 1952 operating season (the winter months), my schedule
averaged twenty cataract operations daily. At that time my cataract
surgery involved using either the erisiphake or Smith Indian technique .
During that period I performed several dozen 'same day' - I prefer
'simultaneous' - bilateral cataract operations. The cataracts were
primarily Morgagnian or cataracta nigra in type. The patients were
legally blind with light perception only. They were primarily rural
patients who in many cases had traveled - many times walked - with
attending family members from distant villages, 'Same day' bilateral
cataract surgery was frequently offered them - a golden opportunity for
patients who might never again have access to surgery in a hospital under
the aegis of the dedicated and skilled Medical Mission Sisters of
Philadelphia. Most patients - and the burdened relatives - readily
accepted the offer of 'same day' bilateral cataract surgery. For the
patient, it was a matter of convenience; for the relatives, it was
matter of expediency. I also realized that with vision restoration in one
eye, the patient - or perhaps more so, the relatives - might not be
interested
in returning for surgery on the second eye. A prevalent philosophy was:
"Two eyes are a luxury , one eye is a necessity". As a result, the
patient frequently would develop the complications of a leaking hypermature (Morgagnian) cataract - phacolytic glaucoma. Such a painful glaucoma - a medical emergency - in a patient distant from acceptable medical care is
a horrendous problem for the patient - and the family .
In spite of my own successful results with 'same day' bilateral
cataract surgery in rural India , even there I was very selective - just
as Dr Johansson has been - in offering this procedure to patients. In
fact, during the eye clinic sessions subsequent to that of 1951-1952, I
did not perform 'same day' bilateral cataract surgery but separated the
two operations by at least a few days. I felt that the risk to the
patient and to the reputation of the hospital was unacceptable. There is
a basic rule in cataract surgery: "The second eye frequently behaves
like the first eye." A complication in the first eye - often a delayed
one - may presage a similar complication in the second when that eye is
subjected to the same surgical procedure. This is particularly
devastating in cases of endophthalmitis - more so in purulent
panophthalmitis. Dr Johansson was fortunate in that it was the second,
not the first eye, of his patient that developed the endophthalmitis.
One can imagine the potentiality for infection of the second eye in cases
where the first eye developed endophthalmitis in a 'same day' bilateral
cataract operation.
In America (USA), 'same day' bilateral cataract surgery with
rare exception cannot be advisable. With a sufficient number of qualified
cataract surgeons with access to readily available ambulatory facilities
and with scheduling of cataract surgery - on the first eye and
subsequently on the second - at the convenience of the patient, Dr
Johansson's standards for 'same day' bilateral cataract surgery would
rarely if ever be met.
In addition, that ever-threatening incubus - the legal profession -
hovers constantly above the American surgeon.
'Same day' bilateral cataract surgery is simply a bete noir for the
American surgeon to avoid.
After completing the 1951-1952 cataract operating season in India, I
returned to my private eye practice in Rochester , New York. There I was
asked by a leading eye surgeon in the area if I would testify in court in
his behalf. He had performed 'same day' bilateral cataract surgery on
an older patient in an attempt to save her the expense of a second
hospital stay. Unfortunately, postoperatively the patient developed
diffuse retinal hemorrhaging bilaterally and was permanently blind with
vaguest light perception. I informed the surgeon - a good friend - that I
could not testify favorably for him, because I felt that he had
demonstrated poor judgment in performing 'same day' bilateral cataract
surgery in America (USA). In court, the eye surgeon was found guilty
of malpractice. From that day he never again performed surgery of any type.
Dr Johansson's criteria in his country and my criteria in India cannot normally be met in contemporary
America (USA).
I read with interest the World View article by Ezegwui et al.[1]
entitled: "The Causes of Childhood blindness: results from schools for
the blind in South Eastern Nigeria". Childhood blindness has profound
consequences not only for the individual but for the family and
community. Approximating the average life span at 60 years, the man-year
loss caused by childhood blindness is roughly six-fold, which...
I read with interest the World View article by Ezegwui et al.[1]
entitled: "The Causes of Childhood blindness: results from schools for
the blind in South Eastern Nigeria". Childhood blindness has profound
consequences not only for the individual but for the family and
community. Approximating the average life span at 60 years, the man-year
loss caused by childhood blindness is roughly six-fold, which directly
or indirectly is an economic burden on society. Therefore, during the
present era of Vision 2020, the Right to Sight publication on childhood
blindness is highly warranted.[2] The present authors, too, are to be
congratulated for this yeoman endeavor. In their discussion, it is very
rightly pointed out that a large number of children can be examined
within a short time by a standard method with low financial costs.[1]
Way back in 1999, we carried out a survey in only available school for
blind in Eastern Nepal. Though the aim of the survey and method of
examinations were similar to the present report, the causes of severe
visual impairment(SVI)/blindness(BL) were found to be different. In our
study, 41.25% had a retinal lesion. Either avoidable (38.75%) or
treatable (including avoidable) diseases were evident in 46.25% of eyes.
Lenticular problem constituted only 4% of the eyes. On the basis of our
experience, together with the present study and previous reports in
literature,[3-8] it seems there is a geographical variation among health
care systems with regard to the causes of SVI/BL. Both avoidable
blindness and treatable eye disease in children should be taken into
consideration.
Thus, it should be our goal to establish Paediatric Ophthalmology units
at all tertiary eye care centres, and to strengthen the primary eye care
system. Also, we should aim to establish more special schools for blind
for blind shildren.
References
(1) I R Ezegwui, R E , U F Ezepue Causes of childhood blindness: results
from schools for the blind in south eastern Nigeria. B J
Ophthalmol 2003;87:20-3
(2) Gilbert C, Foster A. Childhood blindness in the context of vision
2020-the right to sight. Bull World Health Organ
2001;79:227-32
(3) Chirambo MC, Benezra D. Causes of blindness among students in blind
school institutions in a developing country. Br J Ophthalmol
1976;60:665-8.
(4) Worlde-Gebriel Z, Gebru H, West CE. Causes of blindness in children
in the blind schools of Ethiopia. Trop Geogr Med
1992;44:135-41.
(5) Schwab L, Kagame K. Blindness in Africa: Zimbabwe schools for the
blind survey. Br J Ophthalmol 1993;77:410-2.
(6) Gilbert CE, Wood M, Waddel K, et al. Causes of childhood
blindness in East-Africa:results in 491 pupils attending 17 schools for
the blind in Malawi, Kenya
and Uganda. Ophthalmic Epidemiol 1995;2:77-84
(7) Umeh RE, Chukwu A, Okoye O, et al. Treatable causes of
blindness in a school for the blind in Nigeria. Commun Eye Health
1997;10:14-15.
(8) Rahi JS,Gilbert CE, Foster A,MinassianD.Measuring the burden of
childhood blindness. B J Ophthalmol 1999;83:387-8.
I read this article with interest.[1] Here, the authors suggest that the
evaluation of the posterior corneal surface topographic changes after
partial flaps without ablation may help us to know the contribution of the
flap to the corneal elasticity and the increase in posterior corneal
elevation following LASIK.
However, I would like to point out that there are some very important
differences between a...
I read this article with interest.[1] Here, the authors suggest that the
evaluation of the posterior corneal surface topographic changes after
partial flaps without ablation may help us to know the contribution of the
flap to the corneal elasticity and the increase in posterior corneal
elevation following LASIK.
However, I would like to point out that there are some very important
differences between a failed flap and a ablatable flap.
Firstly, as in their own study, some patients with partial flaps had the
hinge in the visual axis. This means that in these patients the flaps have
cut half or less of the central corneal bed, compared to a good flap which
cuts through the whole of the central area.
Secondly the so called thin flaps that were not ablated are most likely to
be epithelial or subepithelial flaps with very little stromal tissue.
Due to these facts any conclusions drawn from partial flaps without
ablation, on the possible outcomes of good flaps with ablation are invalid
and erroneous.
References
(1) N Sharma, A Rani, R Balasubramanya, R B Vajpayee, and R M Pandey. Posterior corneal topographic changes after partial flap during laser in situ keratomileusis. Br J Ophthalmol 2003;87:160-162.
We have been conducting high volume cataract surgery (hospital-based
with full fledged ophthalmic facilities) in rural parts of Maharastra
state in India, conducting about 4000 to 5000 thousand sutureless
cataract extractions with lens implantations in last 5 years.
Patients with mature cataract with vision not more than finger counting
at
5 feet are selected. They all undergo routine eye exams and...
We have been conducting high volume cataract surgery (hospital-based
with full fledged ophthalmic facilities) in rural parts of Maharastra
state in India, conducting about 4000 to 5000 thousand sutureless
cataract extractions with lens implantations in last 5 years.
Patients with mature cataract with vision not more than finger counting
at
5 feet are selected. They all undergo routine eye exams and physical
check ups pre-operatively. We use a frown incision 7 to 7.5mm (white
mature or dark brown cataracts don't get expressed with the
viscoelastics method for incisions smaller then this). Post-op
refraction is done after 6 weeks; the average cylinder is about 1.5 D at
90 degrees.
Unfortunately, we don't have any method to compile this data. Also
follow-up after the final refraction is very poor. I would be grateful
if you could suggest a means to compile this data and utilize it in the
future. We would welcome any suggestions from you.
We thank Drs Sharawary and Mermoud for their interest in our article [1]
and respect their observations. They have made significant contributions
to our understanding of non penetrating surgery in the treatment of
chronic open angle glaucoma.
With any new surgical technique information changes rapidly, and much new
information has appeared since our article was written. The authors note
current li...
We thank Drs Sharawary and Mermoud for their interest in our article [1]
and respect their observations. They have made significant contributions
to our understanding of non penetrating surgery in the treatment of
chronic open angle glaucoma.
With any new surgical technique information changes rapidly, and much new
information has appeared since our article was written. The authors note
current literature as well as the effects of 'the learning curve' that
might affect results. The point of our article was to summarise the then
position and suggest outcome measures to note for the future.
As chronic glaucoma is a very long term disease even medium term results
can only give at best give an indication of the visual outcome of
treatment. Our current knowledge of treatment for these glaucoma's
strongly suggests that the lower the intraocular pressure within the
statistically normal range the better. The evidence to date still suggests
that there is a greater likelyhood of these lower intraocular pressures
being achieved by 'penetrating' rather then 'non penetrating' surgery.
This needs to be taken into account when advising the patient on which
surgical approach would be in their best interest.
Roger Hitchings
Reference
(1) Tan JCH, Hitchings RA. Non-penetrating glaucoma surgery: the state of play. Br J Ophthalmol 2001;85: 234-237.
Regarding the editorial by Khaw et al.[1]
we are surprised that after quite a few years now non-
penetrating filtering surgery (NPFS) remains only
partly understood by many ophthalmologists. There are
at present two main NPFS: viscocanalostomy as
described by Stegmann, in which outflow filtration is at
least in theory not subconjunctival, and deep
sclerectomy with or without an implant or even wi...
Regarding the editorial by Khaw et al.[1]
we are surprised that after quite a few years now non-
penetrating filtering surgery (NPFS) remains only
partly understood by many ophthalmologists. There are
at present two main NPFS: viscocanalostomy as
described by Stegmann, in which outflow filtration is at
least in theory not subconjunctival, and deep
sclerectomy with or without an implant or even with
viscoelastics, the success of which depends on
several outflow routes - an important one being
subconjunctival. Careful postoperative follow up
becomes therefore mandatory and is at least as
important as the procedure itself. If needed
subconjunctival injection of antimetabolites, needling or use of lasers for
goniopuncture, iris
desincarceration and attempts of possible bleb
reduction or closure of possible seidel may be
required. It also becomes evident that
antimetabolites play an important role in high risk
cases for filtration failure undergoing NPFS (apart
from viscocanolostomy as describd by Stegmann).
Furthermore in our hospital we have been using
antimetabolites also in cases requiring low
postoperative IOP such as normal tension glaucoma
since 1994. We do not understand the comment made
stating that greater care should be taken with
antimetabolites used during NPFS, since we
intraoperatively use these agents before the deeper
scleral flap is being excised or even created. Thus
at this stage this does not differ with
trabeculectomy. Later on the anterior chamber is not
entered and furthermore the deep scleral flap which
has been exposed to antimetabolites is being excised
making the danger of intraoperative intraocular
penetration considerably less than with
trabeculectomy (even with unintended macroperforation
during NPFS).
Additional sutures are added in cases of accidental
macroperforaton so that the incidence of early
significant hypotony in the hands of experienced
surgeons with NPFS is not high. Moreover
postoperative suturelysis may then be required in
these cases if the sutures have been made too tight
or too numerous.
References are being made to the article by Brart et al. However how
reliable is it to compare the
efficacy of two procedures without giving the same
chances of success to both? Intraoperative
antimetabolites were used for all trabeculectomies
and yet never with NPFS. Yet strangely enough,
postoperative antimetabolites as well as needling
with an attempt to lift the scleral flap in some,
were used in both groups. The author also writes in
the discussion that patients with successful drainage
at 6 and 12 months following viscocanalostomy had
evidence of subconjunctival drainage of aqueous as
opposed to eyes without successful drainage. Later on
he further states that 'with our viscocanalostomy
technique, the subconjunctival route is the main
pathway' and 'observation of the disappearance of
subconjunctival blebs in our patients with drainage
failure after viscocanalostomy appears to suggest
that subconjunctival fibrosis is responsible'.
Clearly, if antimetabolites are being used in
trabeculectomies, it should be used in NPFS before
any reliable conclusions can be drawn.
Goniopunture was also only done after 18 months which
of course will not be of great help if the outflow
route after the trabeculodescemet's membrane has
scarred down. Thus to promote good filtration in
addition to intraoperative and postoperative use of
antimetabolites, goniopuncture can help in enhancing
and thus in maintaining a flow under the scleral flap.
Using lasers for suturelysis in trabeculectomies or
for goniopuncture in NPFS is part of the
armementarium we have in glaucoma surgery. The final
aim for the patient is not to know whether the
procedure is penetrating or not, but rather how
effective it is so that the discussion on whether or
not to use goniopunture is futile.
For ophthalmologists performing NPFS, the later is
compared to trabeculectomy what phacoemulsification
was to extracapsular cataract extraction. They will
never go back to it unless obliged to do so. However
it is clear that there is a learning curve to this
surgery and that it is not as forgiveful as is
trabeculectomy.
E. Ravinet, MD
A. Mermoud, MD
Reference
(1) Khaw PT, Wells AP, Lim KS. Surgery for glaucoma in the 21st
century. Br J Ophthalmol 2002;86:
710-711.
I found your editorial on glaucoma in the 21st century to be
fascinating.[1] Not only did you give us insight as to where we are in the
field, but you certainly give us provocative insight into where we might
be headed in the pursuit of the perfect glaucoma procedure.
I would like to state at the onset that I have a financial interest
in product involved in this discussion, having develop...
I found your editorial on glaucoma in the 21st century to be
fascinating.[1] Not only did you give us insight as to where we are in the
field, but you certainly give us provocative insight into where we might
be headed in the pursuit of the perfect glaucoma procedure.
I would like to state at the onset that I have a financial interest
in product involved in this discussion, having developed the device which
is presently FDA approved in the United States for anterior capsulotomy
called the Fugo Blade™. In many other parts of the world, this device is
referred to as the Plasma Blade.
The device operates on flashlight size
rechargeable batteries and with this minute power can cut sharper than a
diamond blade with a total cut time of one hour duration. Best stated by
Dr I. Howard Fine, the device operates "like a miniature eximer laser" .
Namely, the device creates an ablation path by employing a focused photon
ablation of tissue with quanta of electromagnetic energy. This does sound
incredible but to quote the last sentence in your editorial "Impossible?
Only if you think so."
There are over 500 doctors trained and certified
in the United States in this technology. The doctors on our certification
list include such notable surgeons such as I Howard Fine, F. Hampton Roy,
Luther Fry, Gregory Scimeca, David Schanzlin, Jan Worst and Dr Daljit
Singh. Dr Jan Worst of the Netherlands has stated, "This device can
change the entire field of surgery, not just ophthalmic surgery. " Dr
Daljit Singh of Amritsar, India has stated, "This is the greatest cutting
device that I have ever used".
There are those who have not used this
device who state that it is merely another electro-cautery unit. The Fugo
Blade™ absolutely has nothing to do with electro-cautery or diathermy.
Consider that it can be operated on batteries as small as coin size,
wristwatch batteries. Yes, this is a new approach to electrosurgery. Such
a new device allows us to perform surgeries, which heretofore were
considered to be impossible just as you discuss in your article. Incisions
are resistance free and bloodless . You can ablate through highly
vascularized tissue such as uveal tissue which will be resistance free and
bloodless. This opens up incredible possibilities for glaucoma surgery.
Dr Daljit Singh of Amritsar, India is presently performing what you
mentioned in the last paragraph of your editorial namely a 5-minute
glaucoma procedure. This is called Transciliary Filtration or Singh
Filtration. We do not have 95% of the patients achieving pressures of 10-12 mm Hg for several decades. However, we do have an impressive success
rate with not a single collapsed anterior chamber in approximately 200
cases in our clinicals. No iridotomy is needed and a 1 cm conjunctival
flap is required. We also are obtaining penetrating insight into the
homeostatic mechanisms in the eye and an enhanced understanding of how the
eye works.
Employing the Fugo Blade™, Dr Daljit Singh has been able to
demonstrate stunning videos of an extensive lymphatic system that exists
subconjunctivally. He showed these videos at the most recent meeting
of ACES, ASCRS and ISRS. He has obtained these findings in human subjects
employing vital stain and based on data obtained by Fugo Blade™ histologic
sections.
We have seen that this subconjunctival lymphatic system is
imperative for homeostasis of tissue fluid in the globe. The exact
microanatomy of this lymphatic system is being worked out. However, we see
a highly suggestive correlation between the lymphatic feeder channels and
Schlemm's canal. These feeder channels sit above Schlemm's canal. We are
beginning to believe that this lymphatic system plays a major role in the
management of extracellular fluid in any pathologic process such an
inflammation or infection but also rules highly in the management of
aqueous fluid exiting from Schlemm's canal.
Also, we find that our studies
demonstrate that a filtration track placed through sclera in an area which
has deficient lymphatics will produce a large bleb, however will not
produce anticipated drop in IOP. Initially, this was confusing; however,
it appears that the mechanism here is that the intraocular aqueous is
escaping through the filtration tract and accumulates under the
conjunctiva. Since the conjunctiva lacks appropriate lymphatics, there is
a large accumulation of aqueous under the conjunctiva thereby creating a
large filtering bleb that lacks the ability to drain the aqueous fluid
back through the orbit and into the vascular system . Dr. Singh's work
will force us to rethink not only our surgical approach to glaucoma but
also, as you suggest in your editorial, our thoughts and concepts about
how the eye functions.
The number of applications that are presently under study in humans
include bloodless plastic surgery, bloodless squint surgery, Fugo Blade™
phacofragmentation, bloodless ablation of fibrovascular bands that exist
in severe retinopathy, and a new procedure coined by Dr. Singh as " Peep
Hole" DCR . This procedure takes about 3-5 minutes wherein a micropore
ablation path is placed through the medial cathal conjunctiva and into the
dacryocyst, providing a port for evacuation of necrotic debris from the
dacryocyst. Also, the ablation path allows probing and flushing of the
area with antibiotic. This has produced excellent results to date on the
10 operated patients. We also are working on exciting protocols for DLEK
and lamellar corneal grafts. Likewise, we now have a marvelous tool which
may bring a quick, repeatable and efficacious presbyopia reversal surgery
into the realm of reality in the foreseeable future. A senior executive of
one of our large ophthalmic companies has called this technology: "the
greatest fundamental technology since the implementation of the laser".
Numerous articles have appeared on this device in the USA since
this device is FDA approved and over 500 American ophthalmologists have
taken a course in this technology and have been certified to use the
technology. Dr I. Howard Fine chose the Fugo Blade as one of the top
eight technologies at the 2002 ASCRS Meeting.2 The technology will be
introduced into the European market and into Japan in 2003. Only a few
lectures on this topic have been given to date outside of the USA and
those include lectures given by Dr I. Howard Fine and Dr Daljit Singh.
Dr David Apple has performed Fugo Blade capsulotomy margin histologic
analysis and presented this data in his Keynote Innovators Lecture at the
2002 ASCRS meeting in Philadelphia. He explained why the Fugo Blade
capsule margin is "desirable" based on his analysis as well as the
authoritative studies of Assia.
Your editorial correctly points out that surgical techniques must be
accompanied by improved understanding. This new technology may help
greatly in this quest. Dr Daljit Singh calls the Plasma Blade "the great
leveler". He firmly believes that this technology may provide an
opportunity to deliver much needed ophthalmic care to the 3rd World. If
this comes to pass, wouldn't it be grand!
Richard J. Fugo MD, PhD
Reference
(1) P T Khaw, A P Wells, and K S Lim. Surgery for glaucoma in the 21st century. Br J Ophthalmol 2002; 86: 710-711.
Dear Editor
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Regarding the editorial by Khaw et al.[1] we are surprised that after quite a few years now non- penetrating filtering surgery (NPFS) remains only partly understood by many ophthalmologists. There are at present two main NPFS: viscocanalostomy as described by Stegmann, in which outflow filtration is at least in theory not subconjunctival, and deep sclerectomy with or without an implant or even wi...
Dear Editor
I found your editorial on glaucoma in the 21st century to be fascinating.[1] Not only did you give us insight as to where we are in the field, but you certainly give us provocative insight into where we might be headed in the pursuit of the perfect glaucoma procedure.
I would like to state at the onset that I have a financial interest in product involved in this discussion, having develop...
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