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Thanks to Dr Fan and coworkers for their letter and interests in our
article.[1]
The conclusion drawn by us was that confocal microscopy was a rapid and
sensitive diagnostic tool for both early diagnosis and non-invasive
follow
-up of fungal keratitis, not that it was a superior to culture and
corneal
biopsy staining techniques in the early stage of fungal keratitis. It is
rapid compared to
cultu...
Thanks to Dr Fan and coworkers for their letter and interests in our
article.[1]
The conclusion drawn by us was that confocal microscopy was a rapid and
sensitive diagnostic tool for both early diagnosis and non-invasive
follow
-up of fungal keratitis, not that it was a superior to culture and
corneal
biopsy staining techniques in the early stage of fungal keratitis. It is
rapid compared to
culture and biopsy staining techniques, since we were able to detect
fungal
hyphae in all rabbit eyes 2 days after fungal inoculation, but at least 2-3 days had to be elapsed to determine any fungal growth on Sabouraud's
agar. Moreover, O'Day et al[2] reported that about one fourth of fungal
cultures became positive only after 2 weeks. Confocal microscopy is also
rapid compared to biopsy staining, since to perform calcofluor staining
some time had to be elapsed.
As stated in our article [3] 'Although in
our model Sabouraud's agar and corneal biopsy techniques showed similar
sensitivity (100%) in the early stage, confocal microscopy appears to
have
a definitive advantage in the later stages of infection, since not all
cases of fungal keratitis could be cultured.' In the abstract section we wrote that 'on days 14 and 22 confocal microscopy was more sensitive
than
culture technique in both treated and untreated animals, since not all
cases of fungal keratitis could be cultured.' I think the conclusion
drawn
is valid in lights of the data provided in the study. In the second
experiment, 6 rabbits were treated with topical fluconazole, 7 rabbits
were treated with oral fluconazole and 7 rabbits were left untreated. On day 14, we observed hyphal fragments (broken in treated corneas and full size in untreated ones) in each 20 corneas by confocal microscopy.
However, only eight of 20 scrapings grew Aspergillus fumigatus on
Sabouraud's agar culture. The difference between groups was
statistically
significant as appeared in the text by utilizing chi square test.
Similarly, on day 22 confocal microscopy revelaed hyphal fragments
totally
14 corneas out of 20 (three in the topically treated, four in the orally
treated, and 7 in the untreated groups). At this stage only 5 corneal
scrapings grew fungus on culture. The difference was statistically
significant again as appeared in the article by utilizing chi square
test.
Thus, superiority of confocal microscopy over culture technique on days
14
and 22 in treated and untreated rabbits was supported well by the data
presented in the article.
In the result section, we were attempting to determine the
efficacies
of topical and oral fluconazole treatment by culture. However, p values
were not correct as a result of typewriting error. The typewriting
errors
must be escaped both our and reviewer's attentions. However, this part
of
result section does not contain any information that could affect any
conclusion drawn as a result of study data. Actually, this part was not
directly linked to the main aim of the study. The authors wish to thank
to
Dr Fan and coworkers for their careful attentions. The correct p values
were given below.
On day 14 (p=0,383 and p=0,296)
On day 22 (p=0342 and p=0,279).
References
(1) Dorothy SP Fan, David TL Liu, Wai-Man Chan, Dennis SC Lam. Comments on Confocal Microscopy of Aspergillus Fumigatus Keratitis [electronic response to Avunduk et al Confocal microscopy of Aspergillus fumigatus keratitis] bjophthalmol.com 2003http://bjo.bmjjournals.com/cgi/eletters/87/4/409#212
(2) O'Day DM, Akrabawi PL, Head WS, et al. Laboratory isolation
techniques
in human and experimental fungal infections. Am J Ophthalmol. 1979;87:688-93.
We read with great interest the article by G Prakash et al.[1]
We are
trained as residents to overcome this problem by using simcoe cannula and
performing manual irrigation and aspiration through the sideport for
removal of subincisional cortex easily even in the presence of a small
rhexis. We have found this to be a much safer technique than other methods
such as using a J shaped cannula o...
We read with great interest the article by G Prakash et al.[1]
We are
trained as residents to overcome this problem by using simcoe cannula and
performing manual irrigation and aspiration through the sideport for
removal of subincisional cortex easily even in the presence of a small
rhexis. We have found this to be a much safer technique than other methods
such as using a J shaped cannula or bimanual aspiration which need expert
hands.We are further trained to perform phacoemulsification through a
limbal or scleral tunnel which can be extended to accommodate a 5.5mm IOL
and left unsutured thereby giving the benefits of suture less cataract
surgery even by a beginner while learning. Once we have mastered
phacoemulsification we switch over to clear corneal tunnels.
Reference
(1) G Prakash, A Kumar and A Purohit. Unusual case of residual cortical lens matter in anterior
chamber. British Journal of Ophthalmology 2003;87:1421.
I thank Dr Okada et al for replying to my letter to the editor regarding
their article "Trans-Tenon's retrobulbar triamcinolone infusion for the
treatment of uveitis".[1]
While speculating that the cause of the lack of therapeutic response to
sub-tenon’s corticosteroids may be because of placement at a site
relatively far from the target zone, I had quoted only the article by
Freeman et al...
I thank Dr Okada et al for replying to my letter to the editor regarding
their article "Trans-Tenon's retrobulbar triamcinolone infusion for the
treatment of uveitis".[1]
While speculating that the cause of the lack of therapeutic response to
sub-tenon’s corticosteroids may be because of placement at a site
relatively far from the target zone, I had quoted only the article by
Freeman et al.[2]
I fully agree that the article by Jennings et al.[3] had ensured reliable
drug placement. This study was quoted only to highlight the point that
injection of steroids by the sub-tenon’s route did not consistently affect
the blood-retinal barrier permeability and that there was no diffusion of
the steroids into the eye in therapeutically meaningful concentrations,
despite accurate drug placement.
References
(1) AA Okada, T Wakabayashi, Y Morimura, S Kawahara, E Kojima, Y Asano and
T Hida. Trans-Tenon’s retrobulbar triamcinolone infusion for the treatment
of uveitis. Br J Ophthalmol 2003;87:968-971.
(2) Freeman WR, Green RL, Smith RE. Echographic localization of
corticosteroids after periocular injection. Am J Ophthalmol 1987 Mar;
15;103(3 Pt 1):281-8.
(3) Jennings T, Rusin MM, Tessler HH, Cunhavaz JG. Posterior sub-tenon’s
injections of corticosteroids in uveitis patients with cystoid macular
edema. Jpn J Ophthalmol 1988;32:385-391.
We write in reference to the letter by Galloway et al. "Macular
infarction after intravitreal amikacin: Mounting evidence against
amikacin".[1]
The authors report a single case of macular infarction in a patient
who had been given intravitreal amikacin for endophthalmitis. They cite
that single case plus some prior literature as reason to support a
change
in the choice of antibiotic fo...
We write in reference to the letter by Galloway et al. "Macular
infarction after intravitreal amikacin: Mounting evidence against
amikacin".[1]
The authors report a single case of macular infarction in a patient
who had been given intravitreal amikacin for endophthalmitis. They cite
that single case plus some prior literature as reason to support a
change
in the choice of antibiotic for intravitreal injection from the
treatment
guidelines based on the results of the Endophthalmitis Vitrectomy Study
(EVS).
While aminoglycoside induced retinal toxicity certainly can occur,
we
disagree with their statement that there is good evidence that
aminoglycosides should not be primary drugs of choice in this disease.
There are several theoretical and practical advantages of
aminoglycosides
over ceftazidime. Amikacin provides concentration dependent killing (so
that the higher concentration of drug the more rapid the kill) which is
not true for ceftazidime.
This is an important issue since high concentrations of drug are
administered by intravitreal injection, thus possibly allowing for more
rapid kill with amikacin. Amikacin is considered to be synergistic with
vancomycin for certain gram positive species, so its use provides
benefit
against gram positive organisms, not just for gram negatives. Gram
positive organisms make up the overwhelming majority of cases of
endophthalmitis. In addition, there has been a recent report that
ceftazidime may precipitate in the vitreous at normal body temperature,[2] possibly making it less available than one might wish in the
vitreous
cavity.
Finally, and very important, is the fact that amikacin has been
found
to be effective in a clinical trial but there is no such evidence yet
available on ceftazidime. The only apparent advantage to ceftazidime is
that it may be a somewhat safer drug in the sense that macular toxicity
has not been reported. Even so, the incidence of macular toxicity is
extremely rare (only 1 in 420 eyes in the EVS suffered macular toxicity
possibly from the drug). In a very severe disease such as
endophthalmitis
a risk this low is worth tolerating when there may be substantial
potential advantages.
References
(1) Galloway G, Ramsay A, Jordan K, et al, Macular infarction after
intravitreal Amikacin: mounting evidence against Amikacin. Br J
Ophthalmol
2002;86:359-360.
(2) Kwok, AK., M. Hui, et al. An in vitro study of ceft)azidime and
vancomycin concentrations in various fluid media: implications for use
in
treating endophthalmitis." Invest Ophthalmol Vis Sci 2002,43(4): 1182-8.
I read with great interest the article by Sitorus et al.[1] on the causes
of
blindness at a blind school in Indonesia. I would like to supplement and clarify certain points mentioned in the article.
It was sobering to note that Indonesia has the highest rate of
blindness (1.5%) among the Asian countries, much more than India (0.7%).
Incidentally, the similarities with the Indian scenario...
I read with great interest the article by Sitorus et al.[1] on the causes
of
blindness at a blind school in Indonesia. I would like to supplement and clarify certain points mentioned in the article.
It was sobering to note that Indonesia has the highest rate of
blindness (1.5%) among the Asian countries, much more than India (0.7%).
Incidentally, the similarities with the Indian scenario were striking.
The
predominance of hereditary and postnatal infectious eye diseases; a
pattern intermediate to that seen in developing and developed countries
and the high proportion of autosomal recessive disorders amongst the
genetic eye diseases due in turn to the high degree of consanguinity
have
been reported previously from India.[2,3]
However, there is an equally striking difference as well.
It was remarkable that the study found that the majority of the students in the blind school had vision that was mostly between hand movements
and
light perception only. In contrast, studies from the Indian subcontinent
have found a high percentage of patients with correctable defective
vision, despite the similar aetiologies of low vision.[4,5]
The study by Hornby et al in six blind schools in India,[4] found that
one
in seven children could read normal print with optical support, with
15.4%
of the children being able to read N10 point although they were studying
Braille! Similarly, treatable refractive error was found to account for
33.3% of childhood blindness in two large population based studies in a
southern Indian state.[5] Although definite conclusions cannot be drawn
from these two studies alone, this could reflect the lack of awareness
or
access to primary eye care for correction of even a simple refractive
error in India. Alternatively, it could mean that children with
uncorrected refractive errors and navigational vision were not admitted
to
the blind schools in Indonesia and were still at large in the community.
Thus, although the aetiologic causes are more or less similar, the
intervention programmes would have to be region-specific and quite
different for both the countries.
The authors have mentioned that all the cases of phthisis bulbi
were due to infection. A significant subset of these cases could be
secondary to uveitis or trauma, that are also quite common in childhood.
It might not be appropriate to attribute all the cases of phthisis bulbi to infection alone.
The article mentions the disturbing fact that blind children with
multiple handicaps were not accepted for admission in the blind schools
in
Indonesia. Similar admission criteria precluding admission of blind
children with mental retardation in blind schools in Ethiopia was
reported previously.[6] Such rules exist in India and China as well. In
contrast, the blind schools in the United Kingdom and the United states,
(where lesions of the central nervous system are the commonest cause of
childhood blindness)[7] allow admission of such children. Considering that
children with mental retardation could also be suffering from cortical
visual impairment (due to perinatal factors such as hypoxic ischaemic
encephalopathy), I wonder whether such regional differences in the
admission criteria of the blind schools could account for the high
prevalence of cortical blindness in the West as opposed to the
developing
countries! This is all the more plausible since much of the information
on
childhood blindness that we have today is based on studies on children
in
schools for the blind.[7]
References
(1) Sitorus RS, Preising M, Lorenz B. Causes of bindness at the "Wiyata
Guna" school for the blind, Indonesia. Br J Ophthalmol 2003;87:
1065-1068.
(2) Rahi JS, Sripathi S, Gilbert CE, Foster A. Childhood blindness in
India: causes in 1318 blind school students in nine states. Eye1995;9:
545
-50.
(3) Rahi JS, Sripathi S, Gilbert CE, Foster A. The importance of prenatal factors in childhood blindness in India. Dev Med Child Neurol
1997;39(7):
449-55.
(4) Hornby SJ, Adolph S, Gothwal VK, Gilbert CE, Dandona L, Foster A.
Evaluation of children in six blind schools of Andhra Pradesh. Indian J
Ophthalmol 2000;48(3): 195-200.
(5) Dandona R, Dandona L. Childhood blindness in India: a population
based perspective. Br J Ophthalmol 2003;87(3): 263-5.
(6) Kello A B, Gilbert C. Causes of severe visual impairment and
blindness
in children in schools for the blind in Ethiopia. Br J Ophthalmol 2003;
87: 526-530.
(7) Gilbert C, Foster A. Childhood blindness in the context of VISION
2020-
the right to sight. Bull World Health Organ 2001;79(3):227-32.
We read with interest Cohen and associates’ report on the onset of
Charles Bonnet syndrome (CBS) following photodynamic therapy (PDT) for
choroidal neovascularization (CNV).[1] An earlier study reported that 16.6%
of patients developed CBS following macular photocoagulation for CNV.[2]
Holroyd and co-workers reported a patient with sudden onset of visual
hallucinations after laser treatment, which cease...
We read with interest Cohen and associates’ report on the onset of
Charles Bonnet syndrome (CBS) following photodynamic therapy (PDT) for
choroidal neovascularization (CNV).[1] An earlier study reported that 16.6%
of patients developed CBS following macular photocoagulation for CNV.[2]
Holroyd and co-workers reported a patient with sudden onset of visual
hallucinations after laser treatment, which ceased after a second laser
treatment one year later.[3] Two other patients’ visual hallucinations
ceased acutely after laser therapy for macular degeneration.[4]
We recently reported a case of CBS following bilateral sequential
Argon-Nd:YAG laser peripheral iridotomies.[5] This case differs from the
others noted above in that the laser treatment involved the anterior
segment of the eye and was not specifically targeted on the retina
although it is possible that some laser energy may have been transmitted
to the posterior pole during the iridotomies. It is therefore interesting
to note that various ophthalmic laser procedures may precipitate as well
as terminate the symptoms of CBS.
Several different mechanisms may be involved in the pathogenesis of
CBS.[6,7] The sensory deprivation theory[8] may explain its onset following
certain ophthalmic laser procedures. An acute reduction in visual acuity
may occur following destruction of foveal tissue during macular
photocoagulation [2,3] and secondary to anterior segment inflammation and
corneal changes after laser peripheral iridotomy.[5] Cohen et al. suggested
that acute anatomical changes at the fovea following PDT could have
triggered visual hallucinations in some patients.[1] To explain cessation of
hallucinations after laser procedures, Holroyd et al. postulated that laser
photocoagulation may have destroyed the neurons causing abnormal sensory
signals, thereby terminating the hallucinations.[4]
Regardless of the mechanism resulting in hallucinations, it appears
that CBS is a possible sequelae of many ophthalmic laser procedures and
these symptoms can be quite distressful to some patients. It may be
useful to ask specifically for symptoms of CBS following laser procedures
as some patients who have been unwilling to discuss their symptoms have
subsequently expressed relief upon learning that CBS does not imply a
psychiatric illness.
References
(1) Cohen SY, Bulik A, Tadayoni R, et al. Visual hallucinations and
Charles Bonnet syndrome after photodynamic therapy for age related macular
degeneration. Br J Ophthalmol 2003;87:977-9.
(2) Cohen SY, Safran AB, Tadayoni R, et al. Visual hallucinations
immediately after macular photocoagulation. Am.J Ophthalmol. 2000;129:815-
6.
(3) Holroyd S, Rabins PV, Finkelstein D, et al. Visual hallucinations
in patients from an ophthalmology clinic and medical clinic population. J
Nerv.Ment.Dis. 1994;182:273-6.
(4)Holroyd S, Rabins PV. A three-year follow-up study of visual
hallucinations in patients with macular degeneration. J Nerv.Ment.Dis.
1996;184:188-9.
(5) Tan CSH, Yong VKY, KG Au Eong. Onset of Charles Bonnet Syndrome
(Formed Visual Hallucinations) Following Bilateral Laser Peripheral
Iridotomies. Eye, in press.
(6) Fernandez A, Lichtshein G, Vieweg WV. The Charles Bonnet
syndrome: a review. J Nerv.Ment.Dis. 1997;185:195-200.
(7) Menon GJ, Rahman I, Menon SJ, et al. Complex visual
hallucinations in the visually impaired: the Charles Bonnet Syndrome.
Surv.Ophthalmol 2003;48:58-72.
(8) Berrios GE, Brook P. The Charles Bonnet syndrome and the problem
of visual perceptual disorders in the elderly. Age Ageing 1982;11:17-23.
We read with great interest the article of Avunduk and
coworkers,[1]
who conducted a study in using confocal microscopy to evaluate
Aspergillus
fumigatus keratitis in treated and untreated rabbits eyes. They
concluded that "confocal microscopy is a rapid and sensitive diagnostic
tool for both the early diagnosis and non-invasive follow-up of fungal
keratitis". In order to justify the statement, two i...
We read with great interest the article of Avunduk and
coworkers,[1]
who conducted a study in using confocal microscopy to evaluate
Aspergillus
fumigatus keratitis in treated and untreated rabbits eyes. They
concluded that "confocal microscopy is a rapid and sensitive diagnostic
tool for both the early diagnosis and non-invasive follow-up of fungal
keratitis". In order to justify the statement, two issues of concern on
the early diagnosis have to be addressed.
The first is about the sensitivity in having positive diagnosis in
the untreated eyes of first experiment. On day 2, all 14 samples were
smear and culture positive for the Asperigilus fumigatus, therefore
confocal microscopy could not demonstrate any superiority in early
diagnosis in term of sensitivity. On days 14 and 22, their conclusion
that
"confocal microscopy was more sensitive than culture
technique" also could not be drawn unless the authors could enlighten us
with supplementary data on the percentages of positive culture in those
periods together with their p values.
Another issue is about computation of statistical values in the
second experiment. The authors implied that topical and orally treated
eyes had significantly lower positive culture growth than the control
group receiving no treatment on days 14 and 22 by listing p values of
0.002 and 0.003. However, in performing the Chi-Square analysis again
with
the data provided, we can only achieve p= 0.391 and p= 0.280 on Day 14
and
p= 0.308 and p= 0.237 on Day 22. We would suggest that statistical
differences cannot be demonstrated in these parts of study, at least,
with
such a sample size.
We appreciate the interest and many comments we have received regarding
our recent article on "Trans-Tenon's retrobulbar triamcinolone infusion
for the treatment of uveitis."[1]
In reply to the comments by Dr
Vedantham, we acknowledge the paucity of experimental data to actually
prove that accurate placement of corticosteroids into the sub-Tenon's
space provides good drug penetration into the ey...
We appreciate the interest and many comments we have received regarding
our recent article on "Trans-Tenon's retrobulbar triamcinolone infusion
for the treatment of uveitis."[1]
In reply to the comments by Dr
Vedantham, we acknowledge the paucity of experimental data to actually
prove that accurate placement of corticosteroids into the sub-Tenon's
space provides good drug penetration into the eye. However, the studies
to
the contrary cited by Dr Vedantham have all used needles to make such
"accurate placement" including the study by Jennings et al.[2] which
utilized the technique described by Tessler.[3] Use of needles represents
not only a potential hazard to the eye in terms of accidental globe
penetration, but also makes it much more difficult to place any sub-
Tenon's injection under the posterior Tenon's capsule near the macula
and/or around the optic nerve. It has been shown that many injections
intended for the sub-Tenon's space merely end up somewhere in the orbit
outside of Tenon's capsule.[4] We believe that our method using a 23
gauge
blunt, curved, long cannula (the one we used was #HS-2764 by Handaya
Co.,
Ltd., Tokyo, Japan) assures accurate placement into the target space.
However, we are in agreement with Dr Vedantham, in that ultimately corticosteroid placed outside of the eye may be no match for the efficacy that may be obtained by corticosteroid placed inside the eye. Yet, we have
found such a high efficacy rate for the trans-Tenon's retrobulbar infusion of triamcinolone in uveitis, that we can conceive of no reason why this treatment should not be tried before procedures such as intravitreal injections that carry risks of severe complications are considered. For
example, as also pointed out by Dr Vedantham, the risks of intravitreal
corticosteroid injections even include development of a rare form of
mycobacterial endophthalmitis.[5] We strongly encourage all
uveitis and retina specialists who have up until now been disappointed
with the efficacy of their sub-Tenon's corticosteroid injections, to
make
the effort in obtaining an appropriate cannula and revising their
technique before jumping to intravitreal procedures.
In reply to the first comment by Dr Mehta, we acknowledge the
current WHO guidelines, revised for 2003, that include recommendations
for
extrapulmonary tuberculosis.[6] However, we would also like to amend Dr Mehta's comment, in that the WHO admits in those guidelines that there
are
many regimens with reported efficacy including a 6-month regimen of
rifampicin (with streptomycin also given in the initial phase only) for
meningeal tuberculosis. Furthermore, the WHO recommendations are for
active extrapulmonary tuberculosis that has been diagnosed by specimen
examination or strong clinical evidence, and give no recommendations for latent infection. As we have previously reported in a series on intraocular tuberculosis, systemic work-up failed to identify a focus of active tuberculosis in the majority of our patients,[7] and we have come to suspect that the uveitis we observed may be an immune response to
latent tuberculosis antigen sequestered elsewhere. Therefore, the
patients
we described were given a diagnosis of "presumed intraocular
tuberculosis," that is with uveitis presumed to be related to the
Mycobacterium tuberculosis organism. Furthermore, we would like to
clarify
that in the cases of presumed ocular tuberculosis that received trans-
Tenon's retrobulbar triamcinolone infusion,[1] this treatment was judged
to be effective in 2 of 3 eyes. Regardless, since the focus of active or
latent tuberculosis was never identified in our patients, a two-drug
regimen of isoniazid and rifampicin was used as a therapeutic trial for
anti-tuberculosis therapy. A similar therapeutic trial for ocular
tuberculosis, albeit with isoniazid alone, has been previously advocated
in Japan by Ishihara and Ohno.[8]
With regards to the second comment, among the 16 patients who were
receiving some form of systemic immunosuppressive therapy, we did not
notice any difference in outcome when compared to patients who were not
on
immunosuppressive therapy. In other words, the efficacy of trans-Tenon's
retrobulbar triamcinolone infusion was the same. However, we suspect
that
the recurrence rate after triamcinolone infusion may be different, and
we
are currently investigating this possibility.
References
(1) Okada AA, Wakabayashi T, Morimura Y, et al. Trans-Tenon's retrobulbar
triamcinolone infusion for the treatment of uveitis. Br J Ophthalmol
2003;87:968-971.
(2) Jennings T, Rusin MM, Tessler HH, Cunha-Vaz JG. Posterior sub-Tenon's
injections of corticosteroids in uveitis patients with cystoid macular
edema. Jpn J Ophthalmol 1988;32:385-391.
(3) Tessler H. Uveitis. In: Peyman GA, Sanders DR, Goldberg MF, eds.
Principles and Practice of Ophthalmology, Vol 2, First edition.
Philadelphia: Saunders, 1980;1554-1629.
(4) Freeman WR, Green RL, Smith RE. Echographic localization of
corticosteroids after periocular injection. Am J Ophthalmol
1987;103:281-
288.
(5) Benz MS, Murray TG, Dubovy SR, et al. Endophthalmitis caused by
Mycobacterium chelonae abscessus after intravitreal injection of
triamcinolone. Arch Ophthalmol 2003;121:271-273.
(6) World Health Organization. Case definitions (p. 24) and Standardised
treatment regimens (p. 35-36) In: Treatment of Tuberculosis: Guidelines
for National Programmes. Third edition. (WHO/CDS/TB/2003.313) Accessed
on
13 October 2003. Geneva: World Health Organization.
(7) Morimura Y, Okada AA, Kawahara S, et al. Tuberculin skin testing in
uveitis patients and treatment of presumed intraocular tuberculosis in
Japan. Ophthalmology 2002;109:851-857.
(8) Ishihara M, Ohno S. [Ocular tuberculosis] Nippon Rinsho 1998;56:3157-
3161.
Asthma is a potentially life threatening condition with an ever
increasing morbidity and mortality internationally, the prevalence of
asthma having increased approximately 50% over the last ten to 15
years. Death rates are proportional to the usage of anti-inflammatory
medications effectively.According to the asthma audit in UK too incidence
measured was 3 to 4 times higher in adults and 6 times higher in...
Asthma is a potentially life threatening condition with an ever
increasing morbidity and mortality internationally, the prevalence of
asthma having increased approximately 50% over the last ten to 15
years. Death rates are proportional to the usage of anti-inflammatory
medications effectively.According to the asthma audit in UK too incidence
measured was 3 to 4 times higher in adults and 6 times higher in children
than it was 25 years ago. In 2000, GPs in the UK saw over 18,000 cases
relating to new asthma attacks each week.Currently 1500 people still die
from asthma each year in UK alone.Many more do in the rest of the
world. Many of these deaths might have been prevented with adequate routine
and emergency care. The risk of cataract as determined by Boston
Collaborative Drug Surveillance Program, Boston University School of
Medicine, Lexington was negligible under the age of 40.Moreover there is
conclusive evidence that the risk increases significantly only after 3
years. Cataracts due to steroids tend to be posterior subcapsular in
morphology.Such cataracts are rarely seen in children who were
administered inhaled steroids.[3,4] Newer steroids like budesonide may
further reduce the risk with dosages upto 6 years.[5] In addition,
individual susceptibility plays a role in affecting risk.[6] Hence the need
for a prospective double blind study with a good follow up cannot be
undermined. It would be highly erroneous to presume potentially life saving
drugs especially useful in children as risky on the basis of a
retrospective analysis that too statistical.It would further be incorrect
to comment on the risk of cataract formation without having a look at the
type of cataract which is formed and the effect of the drug on the rate of
formation of the characteristic cataract without taking into consideration
individual susceptibility; thus undermining its use in peadiatric
population where it is relatively safe and the benefits far overweigh the
risks especially with newer steroids.
References
(1) Jick SS, Vasilakis-Scaramozza C, Maier WC. The risk of cataract among
users of inhaled steroids.
Epidemiology. 2001 Mar;12(2):229-34.
(2) Garbe E, Suissa S, LeLorier J.Association of inhaled corticosteroid use
with cataract extraction in elderly patients.JAMA. 1998 Aug 12;280(6):539-
43.
(3) Toogood JH, Markov AE, Baskerville J, Dyson C.Association of ocular
cataracts with inhaled and oral steroid therapy during long-term treatment
of asthma.J Allergy Clin Immunol. 1993 Feb;91(2):571-9.
(4) Simons FE, Persaud MP, Gillespie CA, Cheang M, Shuckett EP. Absence of
posterior subcapsular cataracts in young patients treated with inhaled
glucocorticoids. Lancet. 1993 Sep 25;342(8874):776-8.
(5) Agertoft L, Larsen FE, Pedersen S.Posterior subcapsular cataracts,
bruises and hoarseness in children with asthma receiving long-term
treatment with inhaled budesonide.
Eur Respir J. 1998 Jul;12(1):130-5.
(6) Barenholtz H. Effect of inhaled corticosteroids on the risk of cataract
formation in patients with steroid-
dependent asthma. Ann Pharmacother. 1996 Nov;30(11):1324-7.
(7)Abuekteish F, Kirkpatrick JN, Russell G. Posterior subcapsular cataract
and inhaled corticosteroid therapy.
Thorax. 1995 Jun;50(6):674-6.
I thank Dr Rahman and his colleagues for their comments.
1.
Clinically and historically Charles Bonnet Syndrome (CBS) is indeed a
disorder of the elderly, in spite of rare reports of the syndrome in young
patients.
2. Space constraints imposed by editorial considerations
prevented us from discussing the nuances of CBS in detail. But, we state
quite clearly in the first sentence...
I thank Dr Rahman and his colleagues for their comments.
1.
Clinically and historically Charles Bonnet Syndrome (CBS) is indeed a
disorder of the elderly, in spite of rare reports of the syndrome in young
patients.
2. Space constraints imposed by editorial considerations
prevented us from discussing the nuances of CBS in detail. But, we state
quite clearly in the first sentence of the discussion that CBS occurs "in
the setting of significant bilateral prechiasmal impairment". This visual
impairment can be rather severe central vision loss, as in age related
macular degeneration, or a combination of central vision loss with
peripheral visual field loss as documented in our patients.
3. If our
patients, including case 4, were not taking brimonidine tartrate eye drops
we would have diagnosed them with CBS. Therefore, we feel justified in
concluding that brimonidine tartrate precipitated the CBS in our patients,
and we agree that this should be considered a potential side effect of
this medication.
Dear Editor
Thanks to Dr Fan and coworkers for their letter and interests in our article.[1]
The conclusion drawn by us was that confocal microscopy was a rapid and sensitive diagnostic tool for both early diagnosis and non-invasive follow -up of fungal keratitis, not that it was a superior to culture and corneal biopsy staining techniques in the early stage of fungal keratitis. It is rapid compared to cultu...
Dear Editor
We read with great interest the article by G Prakash et al.[1]
We are trained as residents to overcome this problem by using simcoe cannula and performing manual irrigation and aspiration through the sideport for removal of subincisional cortex easily even in the presence of a small rhexis. We have found this to be a much safer technique than other methods such as using a J shaped cannula o...
Dear Editor
I thank Dr Okada et al for replying to my letter to the editor regarding their article "Trans-Tenon's retrobulbar triamcinolone infusion for the treatment of uveitis".[1] While speculating that the cause of the lack of therapeutic response to sub-tenon’s corticosteroids may be because of placement at a site relatively far from the target zone, I had quoted only the article by Freeman et al...
Dear Editor
We write in reference to the letter by Galloway et al. "Macular infarction after intravitreal amikacin: Mounting evidence against amikacin".[1]
The authors report a single case of macular infarction in a patient who had been given intravitreal amikacin for endophthalmitis. They cite that single case plus some prior literature as reason to support a change in the choice of antibiotic fo...
Dear Editor
I read with great interest the article by Sitorus et al.[1] on the causes of blindness at a blind school in Indonesia. I would like to supplement and clarify certain points mentioned in the article.
It was sobering to note that Indonesia has the highest rate of blindness (1.5%) among the Asian countries, much more than India (0.7%). Incidentally, the similarities with the Indian scenario...
Dear Editor
We read with interest Cohen and associates’ report on the onset of Charles Bonnet syndrome (CBS) following photodynamic therapy (PDT) for choroidal neovascularization (CNV).[1] An earlier study reported that 16.6% of patients developed CBS following macular photocoagulation for CNV.[2] Holroyd and co-workers reported a patient with sudden onset of visual hallucinations after laser treatment, which cease...
Dear Editor
We read with great interest the article of Avunduk and coworkers,[1] who conducted a study in using confocal microscopy to evaluate Aspergillus fumigatus keratitis in treated and untreated rabbits eyes. They concluded that "confocal microscopy is a rapid and sensitive diagnostic tool for both the early diagnosis and non-invasive follow-up of fungal keratitis". In order to justify the statement, two i...
Dear Editor
We appreciate the interest and many comments we have received regarding our recent article on "Trans-Tenon's retrobulbar triamcinolone infusion for the treatment of uveitis."[1]
In reply to the comments by Dr Vedantham, we acknowledge the paucity of experimental data to actually prove that accurate placement of corticosteroids into the sub-Tenon's space provides good drug penetration into the ey...
Dear Editor
Asthma is a potentially life threatening condition with an ever increasing morbidity and mortality internationally, the prevalence of asthma having increased approximately 50% over the last ten to 15 years. Death rates are proportional to the usage of anti-inflammatory medications effectively.According to the asthma audit in UK too incidence measured was 3 to 4 times higher in adults and 6 times higher in...
Dear Editor
I thank Dr Rahman and his colleagues for their comments.
1. Clinically and historically Charles Bonnet Syndrome (CBS) is indeed a disorder of the elderly, in spite of rare reports of the syndrome in young patients.
2. Space constraints imposed by editorial considerations prevented us from discussing the nuances of CBS in detail. But, we state quite clearly in the first sentence...
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