Editor,
We read Frau et al's report with interest and noted
that our article in Ophthalmology was not cited as
reference (Larkin G, Flaxel C, Leaver P. Phacoemulsification and silicone
oil removal through a single corneal incision.
Ophthalmology 1998;105:2023-7). In
this article, we reported our experience at Moorfields Eye Hospital with
34 eyes prospectively evaluated to l...
Editor,
We read Frau et al's report with interest and noted
that our article in Ophthalmology was not cited as
reference (Larkin G, Flaxel C, Leaver P. Phacoemulsification and silicone
oil removal through a single corneal incision.
Ophthalmology 1998;105:2023-7). In
this article, we reported our experience at Moorfields Eye Hospital with
34 eyes prospectively evaluated to look at the efficacy and potential
complications of combined cataract extraction and silicone oil removal
with posterior chamber lens implantation. We also reported the method of
Ms Maria Restori, BSc, MSc, MIPSM, Ophthalmic Ultrasound Specialist at
Moorfields Eye Hospital for calculating the IOL power in an oil filled eye
with correction for the specific gravity of silicone oil taken into
consideration.
Our findings were that the procedure was safe and effective for these eyes
that had often had many previous surgeries. The visual outcome in these
eyes was generally good with improvement in visual acuity, even with
recurrent retinal detachment or pre-existing macular pathology. We also
concluded that it was safer to place a rigid posterior chamber implant
after silicone oil removal due to potential contraction of the anterior
capsule limiting the view of the retina post-operatively. Our technique
was a passive technique but might easily be done with the I/A handpiece as
this group reported.
We feel that it would have been appropriate for them to make reference to
our study since it presents a much larger series with more detailed follow-up.
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 read with interest the article on the use of Medpor lower
eyelid spacers by Tan et al. [1]. The article critically evaluates the
utility of this type of a spacer for retraction of the lower lid. We
would
like to raise a few pertinent issues which may assist in a better
understanding of this challenging entity.
In this article, the authors have not included the assessment of
horizontal lid...
We read with interest the article on the use of Medpor lower
eyelid spacers by Tan et al. [1]. The article critically evaluates the
utility of this type of a spacer for retraction of the lower lid. We
would
like to raise a few pertinent issues which may assist in a better
understanding of this challenging entity.
In this article, the authors have not included the assessment of
horizontal lid laxity in their preoperative evaluation of patients.
Preoperative assessment of horizontal lid laxity and the integrity of
the
Canthal tendons is vital for deciding the adjunctive procedure to be
undertaken. This could be in the form of a lid shortening procedure or
strengthening of the canthal tendons, which should ideally be performed
along with the primary procedure [2]. Otherwise the desired effect of
placing a spacer may not be achieved. Moreover, if it is done as a
secondary procedure, it may be complicated as it may need to be combined
with implant trimming or exchange.
Further, it has been mentioned in the article that the orbital
septum
was incised to allow the implant to slip behind the orbital rim in
downgaze, in cases where lid dynamicity was required. Here it needs to
be
emphasized that extra care should be taken for securely fixing the
implant to prevent its posterior migration, which could lead to a host
of
undesirable sequelae. We suggest that a non-absorbable suture with good
tensile strength such as Prolene should be used for fixating the implant
to the lower border of the tarsus. This would ensure a more permanent
and
stable fixation and minimize the chances of extrusion or migration of
the
spacer.
The authors have mentioned that some patients had had previous
procedures such as hard palate and scleral spacers to correct lower lid
retraction. It is a common clinical experience that a second or
subsequent
surgery is usually associated with a multitude of poor prognostic
factors.
It would be very interesting to know if the authors encountered any
special problems in this subset of patients due to prior cicatrization
or
increased weight and thickness of the lower lid which could reduce the
effectiveness of the Medpor spacer.
References
(1) Tan J, Olver J, Wright M, Maini R, Neoh C, Dickinson AJ. The use of
porous polyethylene (Medpor) lower eyelid spacers in lid heightening and
stabilisation. Br J Ophthalmol. 2004 Sep;88(9):1197-200.
(2) Patel BC, Patipa M, Anderson RL, McLeish W. Management of
postblepharoplasty lower eyelid retraction with hard palate grafts and
lateral tarsal strip. Plast Reconstr Surg. 1997 Apr;99(5):1251-60
Editor,
I have visited the Kikuyu Eye Unit near Nairobi on a yearly basis since
1992, and have witnessed at first hand both there and in Somalia the
enormous burden of poverty and ill health described and quantified in the
editorial. What strikes me very forcibly is the sheer number of hugely
disadvantaged people. This, and the distressing and widening disparity in
health and income between these peopl...
Editor,
I have visited the Kikuyu Eye Unit near Nairobi on a yearly basis since
1992, and have witnessed at first hand both there and in Somalia the
enormous burden of poverty and ill health described and quantified in the
editorial. What strikes me very forcibly is the sheer number of hugely
disadvantaged people. This, and the distressing and widening disparity in
health and income between these people and those of us living in developed
countries is well made in the editorial. I have come to feel that efforts
at population control should receive a high priority, and in this regard I
was surprised and disappointed that the IHPN makes no mention of this in
their checklist of strategies to reduce the global burden of poverty and
poor health. I would be very interested to hear their response.
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.
Recently, Munkwitz et al. reported excellent sensitivities and
specificities of scanning laser polarimetry in detecting glaucoma when
printouts were subjectively evaluated by experts having at least nine
years experience with the device [1].
The authors clearly defined a major difference with previously
published studies, in that they evaluated GDx printouts of both eyes,
although 23 of the...
Recently, Munkwitz et al. reported excellent sensitivities and
specificities of scanning laser polarimetry in detecting glaucoma when
printouts were subjectively evaluated by experts having at least nine
years experience with the device [1].
The authors clearly defined a major difference with previously
published studies, in that they evaluated GDx printouts of both eyes,
although 23 of the glaucoma patients' eyes demonstrated no detectable
nerve fiber bundle defecton red free photography. Although potentially
causing someselection bias, this resembles a "real-life" situation,
where patients
afflicted with glaucoma often present with asymmetric damage. In a
recent
study we conducted using the Heidelberg Retina Tomograph, information
from
both eyes in the form of an asymmetry ratio detected and correlated with
disease severity [2], and thus asymmetry may explain in part some of the
authors success in subjectively detecting glaucoma.
Although the authors' conclusion that "training in interpreting GDx
printouts can greatly improve sensitivity" has yet to be proven, perhaps
the experts may share with their readers some of the clinical pearls
that
were used in their subjective assessment so as to improve our level of
clinical care.
References
(1) Munkwitz S, Funk J, Loeffler KU et al, Sensitivity and specificity
of scanning laser polarimetry using the GDx., Br J Ophthalmol. 2004
Sep;88(9):1142-5.
(2) Harasymowycz P, Davis B, Xu G et al, The use of RADAAR (ratio of rim
area to disc area asymmetry) in detecting glaucoma and its severity.,
Can
J Ophthalmol. 2004 Apr;39(3):240-4.
Editor,
We congratulate Hugh Taylor on his editorial in which he discusses the volume of cataract surgery which needs to be done. We were particularly interested by his calculations drawing attention to the effect of changing the visual threshold at which the decision to undertake cataract surgery is made.
We have reviewed a series of eight audits of cataract surgery to determine the visual acuities a...
Editor,
We congratulate Hugh Taylor on his editorial in which he discusses the volume of cataract surgery which needs to be done. We were particularly interested by his calculations drawing attention to the effect of changing the visual threshold at which the decision to undertake cataract surgery is made.
We have reviewed a series of eight audits of cataract surgery to determine the visual acuities at which patients were put on the waiting list for cataract extraction. The audits were designed to show surgical outcomes but they also list the visions at the point when the decision to operate
was made. They include all patients during short periods between 1982 when intracapsular extraction without lens insertion was the norm and the first six months of 2000 when practically all cases were phacoemulsification through a clear corneal incision with a foldable lens.
They are all based on the throughput of a single firm of a teaching hospital. The table shows visual acuity at listing for cataract extraction.
Audit date
No of cases in audit
Type of surgery
Percentage of patients with a given visual acuity when
decision to operate was taken
6/60 or worse
6/18 to 6/60
6/12 or better
1982
39
ICCE & no lens
76.9
20.5
2.6
1984
68
ECCE & IOL
70.6
25.0
4.4
1988
56
ECCE & PC.IOL
67.9
32.1
0.0
1989
29
ECCE & PC.IOL
62.1
34.5
3.4
1992
23
ECCE & PC.IOL
21.7
69.6
8.7
1998
56
Phaco & IOL
16.1
44.6
39.3
1999
85
Phaco & IOL
14.1
54.1
31.8
2000
41
Phaco & IOL
19.0
33.3
47.7
These results are heartening in that they show that the pool of dense cataracts resulting in visions of 6/60 or worse has decreased (from 77% in 1982 to 19% in 2000). They confirm that as surgical techniques have improved the demand for surgery at an early stage has dramatically increased. In the 1982 audit only 2.6% of cases saw 6/12 or better whereas
by 2000 this figure had risen to 47.7%.
We accept that visual acuity is far from being a comprehensive measure of visual disability but none the less it is useful as an indicator of trends. The trend is clearly towards earlier cataract surgery and it is likely to be maintained resulting in increasing surgical volumes. The answer to Hugh Taylor's question, "How much surgery do we have to do?" is more and still
more. The problem then becomes partly political in that governments decide on maximum waiting times for surgery with the effect that it becomes difficult to prioritise those patients with a serious degree of cataract
over those who are simply suffering inconvenience.
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.
We read the interesting article by L Wickham and associates,
“Vitrectomy and gas for inferior break retinal detachments: are the
results comparable to vitrectomy, gas and scleral buckle?” [1]. They have compared the results of vitrectomy and gas without scleral buckle (Group A) with, vitrectomy and
gas with scleral buckle (Group B) for inferior break retinal detachments.
We would like to point out to a...
We read the interesting article by L Wickham and associates,
“Vitrectomy and gas for inferior break retinal detachments: are the
results comparable to vitrectomy, gas and scleral buckle?” [1]. They have compared the results of vitrectomy and gas without scleral buckle (Group A) with, vitrectomy and
gas with scleral buckle (Group B) for inferior break retinal detachments.
We would like to point out to a possible error in the results section.
The authors have shown the distribution of retinal breaks using Venn
diagrams. Figure 1 shows that 16 patients in Group A had breaks confined
to 4-8 o’clock, 12 patients had breaks in 4-8 o’clock and 12-4 o’clock, 1
had breaks in 4-8 o’clock and 8-12 o’clock and breaks were scattered all
around in 1 patient. This comes to a total of 30 patients as against 41
patients included in Group A. This possible error in the diagram gives a
false impression that, Group B patients had retinal breaks that were more
widely distributed and also probably had more number of retinal breaks in
total. We are curious to know about this.
References
(1) L Wickham, M Connor, GW Aylward. Vitrectomy and gas for inferior
break retinal detachments: are the results comparable to vitrectomy, gas
and scleral buckle? Br J Ophthalmol 2004; 88: 1376-9.
Editor
The article by Forbes et al on cheek mucosa is indeed interesting and helpful in cases of reccurent pterygia, but as they have given irradiation to cases after surgery it becomes a bias as to how much better is cheek mucosa compared with conjunctiva autograft.
Secondly, have they considered the use of buccal mucosa for the same as cheek mucosa is more difficult to harvest although I agr...
Editor
The article by Forbes et al on cheek mucosa is indeed interesting and helpful in cases of reccurent pterygia, but as they have given irradiation to cases after surgery it becomes a bias as to how much better is cheek mucosa compared with conjunctiva autograft.
Secondly, have they considered the use of buccal mucosa for the same as cheek mucosa is more difficult to harvest although I agree that the buccal mucosa is
thicker. I have tried buccal mucosa for severe symblepharons.
Editor,
We read Frau et al's report with interest and noted that our article in Ophthalmology was not cited as reference (Larkin G, Flaxel C, Leaver P. Phacoemulsification and silicone oil removal through a single corneal incision. Ophthalmology 1998;105:2023-7). In this article, we reported our experience at Moorfields Eye Hospital with 34 eyes prospectively evaluated to l...
Dear Editor
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...
Dear Editor
We read with interest the article on the use of Medpor lower eyelid spacers by Tan et al. [1]. The article critically evaluates the utility of this type of a spacer for retraction of the lower lid. We would like to raise a few pertinent issues which may assist in a better understanding of this challenging entity.
In this article, the authors have not included the assessment of horizontal lid...
Editor,
I have visited the Kikuyu Eye Unit near Nairobi on a yearly basis since 1992, and have witnessed at first hand both there and in Somalia the enormous burden of poverty and ill health described and quantified in the editorial. What strikes me very forcibly is the sheer number of hugely disadvantaged people. This, and the distressing and widening disparity in health and income between these peopl...
Dear Editor
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...
Dear Editor
Recently, Munkwitz et al. reported excellent sensitivities and specificities of scanning laser polarimetry in detecting glaucoma when printouts were subjectively evaluated by experts having at least nine years experience with the device [1].
The authors clearly defined a major difference with previously published studies, in that they evaluated GDx printouts of both eyes, although 23 of the...
Editor,
We congratulate Hugh Taylor on his editorial in which he discusses the volume of cataract surgery which needs to be done. We were particularly interested by his calculations drawing attention to the effect of changing the visual threshold at which the decision to undertake cataract surgery is made.
We have reviewed a series of eight audits of cataract surgery to determine the visual acuities a...
Dear Editor
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...
Dear Editor
We read the interesting article by L Wickham and associates, “Vitrectomy and gas for inferior break retinal detachments: are the results comparable to vitrectomy, gas and scleral buckle?” [1]. They have compared the results of vitrectomy and gas without scleral buckle (Group A) with, vitrectomy and gas with scleral buckle (Group B) for inferior break retinal detachments. We would like to point out to a...
Editor
The article by Forbes et al on cheek mucosa is indeed interesting and helpful in cases of reccurent pterygia, but as they have given irradiation to cases after surgery it becomes a bias as to how much better is cheek mucosa compared with conjunctiva autograft.
Secondly, have they considered the use of buccal mucosa for the same as cheek mucosa is more difficult to harvest although I agr...
Pages