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.
We read with great interest the article of Orge and co-workers[1] who
claim a first-ever solution to the problem of non-invasive volumetric
blood flow measurement in the ophthalmic artery. This is a very important
topic both from the clinical and scientific point of view, since blood
supply is an important parameter for example in glaucoma studies. However,
to date for the orbital circulation only the bl...
We read with great interest the article of Orge and co-workers[1] who
claim a first-ever solution to the problem of non-invasive volumetric
blood flow measurement in the ophthalmic artery. This is a very important
topic both from the clinical and scientific point of view, since blood
supply is an important parameter for example in glaucoma studies. However,
to date for the orbital circulation only the blood velocity has been
measurable; from this the resistivity indices can be calculated, but the
volumetric flow cannot be determined because the small diameter of the
orbital vessels does not allow the vessel diameter measurement which is
indispensable for such calculation.
In spite of the novelty of the report and the extensive analysis of
the authors on the possible sources of high variability of volumetric flow
measurements, it appears to us that there are several points which need
further consideration; some of these were analysed in the Editorial by T R
Hedges,[2] but we would like to highlight two additional questions.
For us, a weak point of the study protocol of Orge and colleagues[1] is
their method for the diameter determination of the ophthalmic artery. They
assume the boundaries of the vessel to be where detected movement starts
and ends along the m-mode line; or in other words the vessel boundaries
are taken to be the positions where the grey pixels and colour pixels
touch on this Doppler image. However, we are doubtful whether this
definition is relevant for the required quantitative measurement. The
first point is that for small vessels the width of the colour area
(indicating blood motion) is unfortunately relatively independent of the
true vessel diameter. The width of the superimposed colour area is greatly
influenced by the actual technical parameters used in color Doppler
imaging (pulse repetition frequency, lateral dimension of the ultrasound
beam, colour priority, motion discriminator setting, colour saturation,
brightness, contrast, etc). Our second doubt is that even on the grey-scale part of the image shown by the present authors in their Figure 1, no
vessel wall is seen, unlike the case for typical images of large vessels
like the carotid arteries.
We think that because of these difficulties regarding the
determination of the vessel wall position, Orge and co-workers
overestimate the ophthalmic artery diameter. Their diameter estimate is
2.02 mm on average; but this figure is significantly larger than is
suggested by other evidence. During conventional 10 MHz B-scan diagnostic
examination, the ophthalmic artery is never visible. However for the
dilated ophthalmic vein, in exceptional cases such as in a patient with
carotideo-cavernous sinus fistula, or in a small baby in a bout of
strenuous crying, the vein is then well outlined with a diameter of 1 mm
or above. Thus, we would expect a 2 mm diameter artery to be clearly
visible. As we demonstrated some years ago,[3,4] patients with a
pathologically dilated ophthalmic vein are good candidates for non-
invasive volumetric blood flow measurement. We were able to measure
volumetric blood flow in the orbit of patients with a high flow fistula
(vein diameter around 3-4 mm) using the CVI-Q technique.
Possibly future improvements in spatial resolution may resolve this
difficulty.
In a vessel like the ophthalmic artery there is a further problem in
determination of the average velocity, because the laminar flow in such
small vessels causes a very wide velocity variation within the lumen. In contrast, we note that the colour
spectrum in the figure presented by the authors is almost completely
uniform and does not show higher speed in the centre of the lumen compared
to that close to the vessel wall. This might imply a relatively
insensitivity of velocity discrimination within a small vessel lumen,
which in addition may be of irregular cross-sectional shape (i.e. not
circular) but is only measured in one longitudinal plane. We agree with
the authors that the analysis software is of great importance and may be a
key factor in dealing with this complex situation.
In spite of our reservations mentioned above we, and many other
workers concerned with orbital circulation, are in urgent need of a
reliable solution for volumetric blood-flow determination in the orbit.
The results of Orge and co-workers[1] show that we are probably not far from
a definitive solution.
References
(1) Orge F, Harris A, Kagemann L et al. The first technique for non-
invasive measurements of volumetric ophthalmic artery blood flow in
humans. Br J Ophthalmol 2002;86:1216-9.
(2) Hedges TR. Ophthalmic artery blood flow in humans. The tortuosity and
the variable course of the ophthalmic artery remain a problem. Br J
Ophthalmol 2002;86:1197.
(3) Németh J, Harkányi Z. Color Doppler and color velocity imaging of the
orbital vessels
In: Süveges I, Follmann P, (Eds) XIth Congress of the European Society of
Ophthalmology. Bologna: Monduzzi. 1997:593-6.
(4) Németh J, Süveges I, Harkányi Z. Color Velocity Imaging of Orbital
Blood Circulation
In: Hasenfratz G. (Ed.) Ultrasound in Ophthalmology, Proceedings of the 16th
SIDUO Congress Munich, Germany 1996. Regensburg: Roderer Verlag. 2000:31-3.
2
We read with keen interest the paper by Kageyama et al,[1] which analyzed the
results of performing phacoemulsification with dominant versus non-dominant hand. The
results were also interesting; vitreous loss was higher with dominant hand group (5.9%
vs.3.4%) and opposite in case of endothelial cell loss. Even though vitreous loss has been
similar to a few other reports of conventional superior inc...
2
We read with keen interest the paper by Kageyama et al,[1] which analyzed the
results of performing phacoemulsification with dominant versus non-dominant hand. The
results were also interesting; vitreous loss was higher with dominant hand group (5.9%
vs.3.4%) and opposite in case of endothelial cell loss. Even though vitreous loss has been
similar to a few other reports of conventional superior incision by trainees, there are also
studies that reports lesser percent of vitreous loss (Prasad et al.:2.9%,[2] Corey RP et al:
1.8%,[3] Seward et al: 1.5%,[4] Pedersen et al: 2.1%[5]). The favourable results for non-dominant
hands could have been due to chance since the trainees were not picked up
randomly. Intraoperative complications could have been probably low if trainees were
allowed to operate on all eyes with their dominant hands as in our institution.
Briefly, in our system each operating surgeon operates on two tables with a
microscope set to swing between tables. Two surgeon’s chairs are placed on the sides of
operating tables. While the surgeon operates on one table, another patient is prepared for
surgery on the other table. After completion of surgery, the surgeon swings the
microscope to the other table and operates on the next patient. Assisting nurses are
trained to designate right and left eye surgery patient to right and left tables, respectively.
This automatically makes surgeons sit on temporal side and operate with their dominant
hand. There is no need for repositioning chairs or equipments, increase staff or a high risk
of infection in our system.
References
(1) T Kageyama, S Yaguchi, Y Metori, et al. Visual results and complications of
temporal incision phacoemulsification performed with non-dominant left hand by
junior ophthalmologists. Br J Ophthalmol 2002; 86:1222-1224
(2) Prasad S. Phacoemulsification learning curve: experience of two junior trainee
ophthalmologist. J Cataract Refract Surg 1998; 24:73-77.
(3) Corey RP, Olson RJ.Surgical outcomes of cataract extractions performed by
residents using phacoemulsification. J Cataract Refract Surg 1998; 24:66-72
(4) Seward HC, Dalton R, Davis A. Phacoemulsification during the learning curve:
risk/benefit analysis. Eye 1993 ; 7:164-168.
(5) Pedersen OO. Phacoemulsification and intraocular lens implantation in patients with
cataract. Experiences of a beginning ‘phacoemulsification surgeon’. Acta Ophthalmol
1990; 68:59-64.
We read with interest the article on immediate sequential phacoemulsification
(ISP) by Wertheim et al.[1] Bilateral intraocular surgery has been a controversial topic for
ophthalmologist because of the risk of bilateral catastrophic complications such as
endophthalmitis. Unilateral cataract surgery may result in anisometropia which can be
debilitating for a person who could have been performing fine...
We read with interest the article on immediate sequential phacoemulsification
(ISP) by Wertheim et al.[1] Bilateral intraocular surgery has been a controversial topic for
ophthalmologist because of the risk of bilateral catastrophic complications such as
endophthalmitis. Unilateral cataract surgery may result in anisometropia which can be
debilitating for a person who could have been performing fine jobs comfortably before
the onset of cataract or even with a pair of corrective glasses after the onset of cataract. In
developing countries, bilateral intraocular surgery is done mostly in patients who have
dense cataracts obscuring vision totally in both eyes and usually done after a few days
after the first surgery.
A recent study by Minasian et al. argues that scheduled outpatient visits
(preoperatively and postoperatively) and unscheduled visits could have manifested as a
major patient cost component of cataract surgery.[2] Unpublished data from our institute
reveals that patients cost were at least 1.5 times lesser for Phacoemulsification compared
to Extracapsular Cataract Extraction with Posterior Chamber Intraocular Lens.
Extrapolating the scenario to sequential bilateral surgeries, the economic benefits would
be much more.
This technique is of particular relevance to developing countries like India as it
curtails cost of scheduled and unscheduled visits and cost of buying spectacles. As recent
surgical techniques and preoperative prophylaxis resulting in reduced incidence of
endophthalmitis[3] is becoming available in developing countries like India, bilateral
cataract surgery can greatly reduce cost to providers and patients. However, more clinical
trials are required in developing countries for adopting sequential surgeries as a policy,
which can be an incentive for increasing number of cataract surgeries.
References
(1) Werthiem M, Burtan R. Immediately sequential phacoemulsification performed
under topical anaesthesia as day case procedures. Br J Ophthalmol 2002;86:1356-58.
(2) Minassian DC, Rosen P, Dart JKG et al. Extracapsular cataract extraction
compared with small incision cataract surgery by phacoemulsification a
randomized trial. Br J Ophthalmol 2001; 85: 822-29.
(3) Schmitz S, Dick HB, Krummenauer F, Pfeiffer N. Endophthalmitis in cataract
surgery. Ophthalmology 1999;106:1869-77.
I read with interest your paper the effect of acitretin on interstitial
keratitis. However, I am left with a few questions. First, you suggest the
interstitial keratitis in your patient was due to tuberculosis, but you do
not comment on diagnostics: was a PCR performed on aqueous fluid? was the
button of the left eye in 1993 histologically examined?
Secondly, on the photograph there seems to be a hypopyon p...
I read with interest your paper the effect of acitretin on interstitial
keratitis. However, I am left with a few questions. First, you suggest the
interstitial keratitis in your patient was due to tuberculosis, but you do
not comment on diagnostics: was a PCR performed on aqueous fluid? was the
button of the left eye in 1993 histologically examined?
Secondly, on the photograph there seems to be a hypopyon present in an
otherwise quiet eye. Could you comment on that?
Of course you must proceed to a cycloplegic refraction, otherwise you
cannot be sure that the refractive error is purely astigmatic. The sign of
the astigmatism may also change after cycloplegia. Moreover, be cautious
about the cylinder value given by the Retinomax if the spherical ametropia
is high.[1]
Reference
(1) How accurate is the hand-held refractor Retinomax in measuring cyclople...
Of course you must proceed to a cycloplegic refraction, otherwise you
cannot be sure that the refractive error is purely astigmatic. The sign of
the astigmatism may also change after cycloplegia. Moreover, be cautious
about the cylinder value given by the Retinomax if the spherical ametropia
is high.[1]
Reference
(1) How accurate is the hand-held refractor Retinomax in measuring cycloplegic refraction : a further evaluation" Strabismus. 19866;3:133-142.
The authors of this article (Tan J C H, and Hitchings R. Non-penetrating
glaucoma surgery: the state of play. Br J Ophthalmol 2001;85:234-237) should be commended on attempting to tackle this issue. Nevertheless we do feel that their fundamental points and principal arguments merit reconsideration.
The authors state categorically that "long term outcomes do not exit
for the newer...
The authors of this article (Tan J C H, and Hitchings R. Non-penetrating
glaucoma surgery: the state of play. Br J Ophthalmol 2001;85:234-237) should be commended on attempting to tackle this issue. Nevertheless we do feel that their fundamental points and principal arguments merit reconsideration.
The authors state categorically that "long term outcomes do not exit
for the newer non-penetrating surgery technique" when in fact long term
(43.2 months +/- 14.3 (SD)) results for deep sclerectomy with collagen
implant have been presented to the European Glaucoma Society (EGS)
Glaucoma Symposium, 2000, and have also been published some time ago.[1] The
study provided a qualified success rate of 94.8% and the complete success
rate, 61.9% after 60 months (survival analysis), with a mean IOP at end of
follow-up of 11.8 +/- 3. The study reported no surgically induced cataract
of the whole series of 105 patients.
The authors, unfortunately, failed to cite a landmark study[2]
comparing deep sclerectomy without an implant to trabeculectomy in the two
eyes of the same patient in a prospective randomised fashion. At 12
months, mean IOP reduction was 12.3 +/- 4.2 (sclerectomy) versus 14.1 +/-
6.4 mmHg (trabeculectomy) (P = 0.15), and an IOP Furthermore the authors cite a study by Gandolfi as personal
communication supposedly providing evidence that "trabeculectomy produces
lower and better sustained IOP control than either viscocanalostomy or
deep sclerectomy". The authors fail to mention however, that in this
particular study postoperative YAG goniopunctures were considered as a
failure criteria. Excluding goniopuncture from the success criteria would
easily be compared to considering laser suture lysis or even YAG
capsulotomies to be failure criteria of glaucoma or cataract surgeries.
Furthermore Gandolfi concluded that Deep sclerectomy was associated with
lower perturbation of lens nuclear transparency (personal communication,
January 2002).
In another point worthy of reconsideration the authors site a study [3]
that allegedly draws attention to high rates of hypotony and hyphaema
after intraoperative conversion of deep sclerectomy to trabeculectomy
following accidental intraopeartive perforation of the trabeculo-
Descemet's membrane (TDM). However the authors again fail to mention, when
quoting this specific study, that "when deep sclerectomy is complicated
with a perforation of the TDM, the long term success rate of the surgery
is similar to that of trabeculectomy". This conclusion would encourage the
surgeons to start their surgery as a deep sclerectomy, knowing that in
case of a perforation and a subsequent transformation to trabeculectomy,
the chances of success would be similar to initial trabeculectomy.
The authors of the paper at hand compare in their figures
viscocanalostomy, deep scelerectomy without an implant, deep sclerectomy
with collagen implant, and deep sclerectomy without suturing the
superficial flap to each other, and thus drawing certain conclusions. The
different techniques have one thing in common, the element of non-
perforation. It is not useful to compare apples and pears.
A major factor in the conflicting, often contradictory, results
available is the element of long learning curves.
As an example one group reported 0% success rate in their first series of
viscocanalostomy patients [4] and then presented their second series with a
success rate of 15%.[5]
The same group also analyzed the depth of their dissection of the
deep sclera [6] to find that they dissected too superficially in 48% of their
cases and too deeply in 17%. Meaning that the proper depth of dissection,
which should bisect transversally the Schlemm's canal deroofing it, was
not achieved in the majority of their cases.
To achieve successful non-penetrating surgery, the dissection of the deep sclerectomy needs to be correct. This entails a total excision of
corneal stroma behind Descemet's membrane and the excision of the inner
wall of Schlemm's canal and the juxtacanalicular trabeculum. An implant
has to be used to maintain the scleral space patent.[7] Laser goniopuncture
should be performed at any postoperative stage when IOP mounts beyond the
target pressure.
We do however wholeheartedly agree with the authors on the importance of
conducting a large-scale multinational randomised prospective trial as the
only possible method to compare non-penetrating glaucoma surgery, or any
other new surgical practice, to trabeculectomy.
Tarek Shaarawy1, MD and André Mermoud2, MD
1. Head Glaucoma unit, Memorial Research Institute of Ophthalmology, Giza,
Egypt.
2. Head Glaucoma unit, University of Lausanne, Switzerland.
References
(1) Shaarawy T, Karlen M, Schnyder C, Achache F, Sanchez E, Mermoud
A. Five-year results of deep sclerectomy with collagen implant. J Cataract Refract Surg 2001;27:1770-8.
(2) El Sayyad F, Helal M, El Kholify H, Khalil M, El Maghraby A.
Nonpenetrating deep sclerectomy versus trabeculectomy in bilateral primary
open-angle glaucoma. Ophthalmology 2000;107:1671-4.
(3) Sanchez E, Schnyder CC, Mermoud A. [Comparative results of deep
sclerectomy transformed to trabeculectomy and classical trabeculectomy].
Klin Monatsbl Augenheilkd 1997;210:261-4.
(4) Jonescu-Cuypers C, Jacobi P, Konen W, Krieglstein G. Primary viscocanalostomy versus trabeculectomy in white patients with open-angle
glaucoma: A randomized clinical trial. Ophthalmology 2001;108:254-8.
(5) Dietlein, T. S. and Krieglstein, G. K. Morphology and pressure-
reducing efficacy after viscocanalostomy. 23. 2001. Paris, European
Glaucoma Society. Closed Meeting of the European Glaucoma Society.
(6) Dietlein TS, Luke C, Jacobi PC, Konen W, Krieglstein GK. Variability
of dissection depth in deep sclerectomy: morphological analysis of the
deep scleral flap. Graefes Arch Clin Exp Ophthalmol 2000;238:405-9.
(7) Shaarawy, T., Nguyen Chr, Schnyder, C., Achache, F., and Mermoud, A.
Comparative study between deep sclerectomy with and without collagen
implant: Long term follow-up. Invest Ophthalmol42(4), S544. 2001.
Saito et al. present a patient with Terson’s syndrome and vitreous
hemorrhage who underwent pars plana vitrectomy and was noted
postoperatively to have developed an ophthalmic artery occlusion. They
propose that the ophthalmic artery was occluded by the spontaneous release
of an embolus from an atheromatous plaque in the internal carotid artery.
This seems unlikely in a 39-year-old male without a...
Saito et al. present a patient with Terson’s syndrome and vitreous
hemorrhage who underwent pars plana vitrectomy and was noted
postoperatively to have developed an ophthalmic artery occlusion. They
propose that the ophthalmic artery was occluded by the spontaneous release
of an embolus from an atheromatous plaque in the internal carotid artery.
This seems unlikely in a 39-year-old male without a prior history of
symptomatic atherosclerotic disease. Although the authors identified
plaques in the patient’s carotid artery by ultrasound, these can be seen
in 11% of asymptomatic males under age 40 and may therefore be an
incidental finding in this case.[1]
An alternate explanation for the patient’s ocular findings is trauma
from the retrobulbar injection. Intravascular injection into the
ophthalmic artery has been reported as a complication of retrobulbar
anesthesia.[2] It is possible that either an intravascular injection or
simply needle-tip trauma resulted in thrombus formation with obstruction
of flow in the ophthalmic artery. It should also be noted that although
acute ophthalmic artery occlusion is the presumed diagnosis, the same
findings could result from simultaneous obstructions of the retinal and
choroidal circulations,[3] also a potential consequence of errant
retrobulbar injection. The possibility that the patient’s chorioretinal
disturbance could have been iatrogenic highlights the importance of a
thorough preoperative discussion with patients about the risks and
benefits of different methods of delivering anesthesia for ophthalmic
surgery.
References
(1) Sun Y, Lin CH, Lu CJ, et al. Carotid atherosclerosis, intima
media thickness and risk factors—an analysis of 1781 asymptomatic subjects
in Taiwan. Atherosclerosis 2002;164:89-94.
(2) Morgan CM, Schatz H, Vine AK, et al. Ocular complications
associated with retrobulbar injections. Ophthalmology 1988;95:660-665.
(3) Brown GC, Magargal LE, Sergott R. Acute obstruction of the
retinal and choroidal circulations. Ophthalmology 1986;93:1373-1382.
The results presented here have a very important impact on the understanding
of
retinopathy of prematurity and its prevention. It also has several
implications for glaucoma treatment. Several drugs have been trying to
show a beneficial effect on ocular blood flow, but there are several
limitations to the methods used. Dorzolamide is thought to have a potential
benneficial effect on optic nerve head circulati...
The results presented here have a very important impact on the understanding
of
retinopathy of prematurity and its prevention. It also has several
implications for glaucoma treatment. Several drugs have been trying to
show a beneficial effect on ocular blood flow, but there are several
limitations to the methods used. Dorzolamide is thought to have a potential
benneficial effect on optic nerve head circulation by inducing a localised
acidosis by blocking
carbonic anhydrase. The results suggest that this effect, if present,
might not be reflected on any method which studies retinal circulation.
Pulsatile ocular blood flow measurements suggest that choroidal
circulation is increased by this drug. Also endothelin mediated retinal
vasoconstriction should be enhanced by other drugs said to affect
vasoregulation, such as unoprostone.
The model presented here, using the same method or any others that combine
doppler and
diameter analysis, should become a very important investigation tool to
evaluate the effect of this and other drugs on retinal circulation and
reversal of hyperoxia-induced vasoconstriction.
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...
Dear Editor
We read with great interest the article of Orge and co-workers[1] who claim a first-ever solution to the problem of non-invasive volumetric blood flow measurement in the ophthalmic artery. This is a very important topic both from the clinical and scientific point of view, since blood supply is an important parameter for example in glaucoma studies. However, to date for the orbital circulation only the bl...
Dear Editor
2 We read with keen interest the paper by Kageyama et al,[1] which analyzed the results of performing phacoemulsification with dominant versus non-dominant hand. The results were also interesting; vitreous loss was higher with dominant hand group (5.9% vs.3.4%) and opposite in case of endothelial cell loss. Even though vitreous loss has been similar to a few other reports of conventional superior inc...
Dear Editor
We read with interest the article on immediate sequential phacoemulsification (ISP) by Wertheim et al.[1] Bilateral intraocular surgery has been a controversial topic for ophthalmologist because of the risk of bilateral catastrophic complications such as endophthalmitis. Unilateral cataract surgery may result in anisometropia which can be debilitating for a person who could have been performing fine...
Dear Editor
I read with interest your paper the effect of acitretin on interstitial keratitis. However, I am left with a few questions. First, you suggest the interstitial keratitis in your patient was due to tuberculosis, but you do not comment on diagnostics: was a PCR performed on aqueous fluid? was the button of the left eye in 1993 histologically examined? Secondly, on the photograph there seems to be a hypopyon p...
Dear Editor
Of course you must proceed to a cycloplegic refraction, otherwise you cannot be sure that the refractive error is purely astigmatic. The sign of the astigmatism may also change after cycloplegia. Moreover, be cautious about the cylinder value given by the Retinomax if the spherical ametropia is high.[1]
Reference
(1) How accurate is the hand-held refractor Retinomax in measuring cyclople...
Dear Editor
The authors of this article (Tan J C H, and Hitchings R. Non-penetrating glaucoma surgery: the state of play. Br J Ophthalmol 2001;85:234-237) should be commended on attempting to tackle this issue. Nevertheless we do feel that their fundamental points and principal arguments merit reconsideration.
The authors state categorically that "long term outcomes do not exit for the newer...
Dear Editor
A question: can we safely say that in children with pure astigmatism cycloplegic refraction is not required?
Dear Editor
Saito et al. present a patient with Terson’s syndrome and vitreous hemorrhage who underwent pars plana vitrectomy and was noted postoperatively to have developed an ophthalmic artery occlusion. They propose that the ophthalmic artery was occluded by the spontaneous release of an embolus from an atheromatous plaque in the internal carotid artery. This seems unlikely in a 39-year-old male without a...
Dear Editor
The results presented here have a very important impact on the understanding of retinopathy of prematurity and its prevention. It also has several implications for glaucoma treatment. Several drugs have been trying to show a beneficial effect on ocular blood flow, but there are several limitations to the methods used. Dorzolamide is thought to have a potential benneficial effect on optic nerve head circulati...
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