Editor, Trichiasis is a posterior misdirection of eyelashes. Due
to constant corneal irritation it can give rise to discomfort, recurrent
infection, corneal ulceration and pannus formation. Several modalities of
treatment exist which include epilation, electrolysis, cryotherapy and
argon laser thermoablation.[1] [2]
Argon laser offers the advantage of being a relatively simple, virtually
painless met...
Editor, Trichiasis is a posterior misdirection of eyelashes. Due
to constant corneal irritation it can give rise to discomfort, recurrent
infection, corneal ulceration and pannus formation. Several modalities of
treatment exist which include epilation, electrolysis, cryotherapy and
argon laser thermoablation.[1] [2]
Argon laser offers the advantage of being a relatively simple, virtually
painless method of destroying the eyelash follicle. It is especially
useful when there is a need to limit contiguous tissue inflammation and
destruction, e.g., ocular pemphigoid.[3] Argon laser can be precisely
applied to the follicle with or without topical anaesthesia. A beam size
of 50 micros, for a duration of 0.1 second and energy levels of 400 to 500
milliwatts is normally used in our clinic.
Thermoablation depends on the absorption of argon laser by pigment. In
our experience, patients with chronic trichiasis, who have undergone
repeated removal of eyelashes with other available methods, have pale
hypopigmented lashes which do not absorb sufficient laser energy. This
makes it difficult and sometimes impossible to get a result in spite of
increasing the energy levels. Recently, we have used a blue skin marker
pen to mark the base of the offending eyelash with the result that argon
laser is better absorbed by the blue pigment. Once there is initial
uptake subsequent shots down the lash root can be easily completed.
In conclusion, we have found the simple and inexpensive technique of
marking eyelash bases useful in increasing the efficacy of argon laser
photoepilation.
1. Bartley GB, Lowry JC. Argon laser treatment of trichiasis. Am J
Ophthalmol 1992;113:71-74.
2. Bartley GB, Bullock JC, Olsen TG, et al. An experimental study to
compare methods of eyelash albation. Ophthalmology 1987;94:1286-1289.
3. Sharif KW, Arafat AF, Wykes WC. The treatment of recurrent trichiasis
with argon laser photocoagulation. Eye 1991;5:591-595.
Editor, It is pleasing to see Tole et al[1] having success with
impression cytology (IC) in the diagnosis of ocular surface squamous
neoplasia (OSSN) and we thank the authors for their acknowledgment of our work.
We continue to use the small cellulose acetate strips because they offer greater sampling flexibility. However, the Biopore membrane could have practical advantages if samples are to be colle...
Editor, It is pleasing to see Tole et al[1] having success with
impression cytology (IC) in the diagnosis of ocular surface squamous
neoplasia (OSSN) and we thank the authors for their acknowledgment of our work.
We continue to use the small cellulose acetate strips because they offer greater sampling flexibility. However, the Biopore membrane could have practical advantages if samples are to be collected from a variety of locations and transported to the laboratory. We strongly recommend the use of the Papanicolaou stain when examining cytological preparations for this squamous neoplasm because the keratinized group offers the biggest challenge to diagnosis. Neither the Giemsa nor haematoxylin and eosin stains used by Tole et al are likely to be as helpful.
Tole et al. note that the accuracy of IC in their hands is very
similar to that quoted in our original publication and their results are also similar to our later report on a much larger group of intraepithelial and invasive histologically confirmed cases.[2] It seems reasonable to assume that both cellulose acetate strips and the Biopore membrane are equally efficient at sampling the ocular surface if the lesion is easily accessible.
The difficulty in interpretation of these specimens caused by the
paucity of literature relating to cytological criteria is noted by Tole et al. A recent publication on the cytomorphology of OSSN[3] may be helpful. It describes the cytological diversity seen in histologically confirmed impressions from 152 different patients including 23 with invasive SCC of the ocular surface.
GLENDA R NOLAN*,**
LAWRENCE W HIRST**
*Division of Anatomical Pathology and Cytopathology,
QHPS-RBHc, Royal Brisbane Hospital 4029, Australia.
**Division of Ophthalmology, Department of Surgery, The University of
Queensland, Brisbane, Australia.
1. Tole DM, McKelvie PA, Daniell M. Reliability of impression
cytology for the diagnosis of ocular surface neoplasia employing the
Biopore membrane. Br J Ophthalmol 2001;85:154-158.
2. Nolan GR, Hirst LW, Bancroft BJ. Impression cytology in the
identification of ocular surface squamous neoplasia: is it
accurate?[abstract] Invest Ophthalmol Vis Sci 1998;39(Suppl 543):2500.
3. Nolan GR, Hirst LW, Bancroft BJ. The cytomorphology of ocular surface squamous neoplasia by using impression cytology. Cancer (Cancer
Cytopathol) 2001;93:60-67.
Editor, We read with interest the article by Valmaggia et al[1] who
studied OKN in patients with macular degeneration. They noted
abnormalities of OKN gain only in patients with large central scotomas.
Therefore an intact macula seems not to be necessary for the generation of
OKN. This implicitly suggests an important role of the peripheral retina
in eliciting an OKN. In this context, it is interes...
Editor, We read with interest the article by Valmaggia et al[1] who
studied OKN in patients with macular degeneration. They noted
abnormalities of OKN gain only in patients with large central scotomas.
Therefore an intact macula seems not to be necessary for the generation of
OKN. This implicitly suggests an important role of the peripheral retina
in eliciting an OKN. In this context, it is interesting to note that we
observed an inversed OKN in some patients with defects of the central
visual field. An inversed OKN is an OKN with fast phases in the
direction opposite to the stimulus. The eyes in which an inversed OKN was
provoked more easily or at lower stimulus velocities had the largest
central field defects. It was a prerequisite to elicit an inversed OKN
that the attention was actively directed to the central field defect. Taking our results[2] and those of Valmaggia et al together, this would suggest that the abnormal OKN in central field defects could not only be due to the field defect itself, but could also be influenced by a remarkable property of the more
peripheral retina to induce an OKN in the inversed direction,
counteracting the OKN in the classical direction. In this central-peripheral interaction, we proposed an important role for the spatial-selective attention.[3] It would be very interesting to find a method to
monitor direction of attention simultaneously with OKN.
1. Valmaggia C, Charlier J, Gottlob I. Optokinetic nystagmus in patients
with central scotomas in age related macular degeneration. Br J
Ophthalmol 2001;85;169-172.
2. Crevits L, van Vliet AGM. Optokinetic nystagmus in patients with
defects of the central visual field. Eur Neurol 1986;25:454-457.
3. Crevits L, van Vliet AGM. Optokinetic nystagmus and spatial-selective
attention. An experimental study. Ophthalmologica 1991;202:105-108.
Editor,
I read the article by Schlote et al with interest. The aim of their
study was to determine the safety and effectiveness of transscleral diode
laser cyclophotocoagulation (TDLC) in post inflammatory eyes with
refractory glaucoma. In addition, the authors have rightly pointed out
that management of inflammatory glaucoma is still a dilemma as many of the
antiglaucoma drugs are either contraindica...
Editor,
I read the article by Schlote et al with interest. The aim of their
study was to determine the safety and effectiveness of transscleral diode
laser cyclophotocoagulation (TDLC) in post inflammatory eyes with
refractory glaucoma. In addition, the authors have rightly pointed out
that management of inflammatory glaucoma is still a dilemma as many of the
antiglaucoma drugs are either contraindicated or ineffective in such eyes.
Further, some surgical procedures may activate the inflammatory diseases.
I congratulate Schlote et al for highlighting the efficacy of TDLC in
inflammatory glaucoma. In this context I would like to share our
experience in one group of such eyes, "Post PK Glaucoma."
Glaucoma following penetrating keratoplasty continues to be a serious
problem because of the frequency of its occurrence, its recalcitrant
nature and the risk of further damaging an already compromised anterior
segment. We found in our study of 8 eyes with uncontrolled post PK
Glaucoma (Table 1) that all the 8 eyes responded to the therapy and the
mean IOP was 17.5+/-1.06 at the end of 24 weeks post TDLC where the
preoperative average intraocular pressure was 32.5+/-3.66. All but one eye
were off systemic antiglaucoma therapy at 6 months. However, all the eyes
were on topical timolol maleate 0.5% B.D. The graft clarity was improved
by one plus in 4 eyes and two plus in one.[1] In three eyes the graft
clarity was worsened. Visual acuity was static in 6 eyes and improved in
one. In one eye the visual acuity was reduced from 3/60 to CF. On the
basis of the reports by Schlote1 et al in 2000 and Spencer and Vernon[2] in
1999, we believe that TDLC is an alternative to treat post PK Glaucoma.
However, considering the non-improvement of visual acuity, worsening of
the graft clarity in 25% of eyes and repeat therapy in 25% of eyes, our
question remained unanswered about the real efficacy of the procedure. It
is, therefore, essential to know from the authors about the efficacy of
TDLC in post PK Glaucoma. Once again I congratulate the authors for
bringing up this important issue.[1]
References
1. Panda A, Shankar KT. Prognosis of PK in viral keratitis. Ann Ophthalmol 1991;23:410-413.
2. Spencer AF, Vernon SA. "Cyclodiode": results of a standard protocol. Br J Ophthalmol 1999;83:311-316.
Editor, We would like to congratulate Heimann and colleagues for
their study on 21 patients presenting with retinal vasoproliferative
tumours treated by cryotherapy, brachytherapy or enucleation. We wonder
whether an intravitreal injection of crystalline cortisone, as single
procedure or in combination with the strategies described by the authors'
study, may be an additional option in the therapeutic...
Editor, We would like to congratulate Heimann and colleagues for
their study on 21 patients presenting with retinal vasoproliferative
tumours treated by cryotherapy, brachytherapy or enucleation. We wonder
whether an intravitreal injection of crystalline cortisone, as single
procedure or in combination with the strategies described by the authors'
study, may be an additional option in the therapeutic armentarium for
these tumours. As suggested by Machemer et al[1-5] and others, intravitreal
injection of triamcinolone acetonide can show marked anti-exudative and
anti-angiogenetic effect in various clinical situations such as exudative
age-related macular degeneration[6] [7] and proliferative diabetic
retinopathy[8] including neovascular glaucoma. The question arises,
therefore, whether the injection of crystalline triamcinolone acetonide
would be helpful in the management of vasoproliferative tumours of the
retina.
References
1. Machemer R, Sugita G. Tano Y. Treatment of intraocular proliferations
with intravitreal steroids. Trans Am Ophthalmol Soc 1979;77:171-180.
2. Machemer R. Five cases in which a depot steroid (hydrocortisone
acetate and methylprednisolone acetate) was injected into the eye. Retina
1996;16:166-167.
3. Ishibashi T, Miki K, Sorgente N, et al. Effects of intravitreal
administration of steroids on experimental subretinal neovascularization
in the subhuman primate. Arch Ophthalmol 1985;103;708-711.
4. Antoszyk AN, Gottlieb JL, Machemer R, et al. The effects of
intravitreal triamcinolone acetonide on experimental pre-retinal
neovascularization. Graefe's Arch Clin Exp Ophthalmol 1993;231:34-40.
5. Danis, RP, Bingaman DOP, Yang Y, et al. Inhibition of preretinal and
optic nerve head neovascularization in pigs by intravitreal triamcinolone
acetonide. Ophthalmology 1996;103:2099-2104.
6. Challa JK, Gillies MC, Penfold PL, et al. Exudative macular
degeneration and intravitreal triamcinolone: 18 month follow up. Aust N
Z J Ophthalmol 1998;26:277-281.
7. Danis RP, Ciulla TA, Pratt LM, et al. Intravitreal triamcinolone
acetonide in exudative age-related macular degeneration. Retina
2000;20:244-250.
8. Jonas JB, Hayler JK, Söfker A, et al. Intravitreal injection of
crystalline cortisone as adjunctive treatment of proliferative diabetic
retinopathy. Am J Ophthalmol 2001; in press.
Editor, We read Tanner et al's paper on the predictive value of
vitreous pigment (Schaffer's sign) for retinal breaks in posterior
vitreous detachment1 with great interest. Based on their figures,
patients who have a negative Schaffer's sign had a 1% chance of having a
retinal tear or hole and a 0.5% chance of having a lesion for which
prophylaxis was thought to be appropriate. Thus Schaffer's sign ha...
Editor, We read Tanner et al's paper on the predictive value of
vitreous pigment (Schaffer's sign) for retinal breaks in posterior
vitreous detachment1 with great interest. Based on their figures,
patients who have a negative Schaffer's sign had a 1% chance of having a
retinal tear or hole and a 0.5% chance of having a lesion for which
prophylaxis was thought to be appropriate. Thus Schaffer's sign has a
negative predictive value of 99% in their series. They go on to recommend
that if vitreous pigment is present then the patient should be referred
for urgent vitreoretinal opinion while those with no pigment should be
referred on a less urgent basis.
We would like to put these findings in perspective. The incidence of
retinal breaks in patients aged 10 years or more who do not have any
history of ocular disease is 6-14%.[1] Retinal breaks have been found in
37/250 (14.8%) of autopsy eyes with posterior vitreous detachment by
Foos.[2] The incidence of retinal detachment is approximately 12/100,000 of
the general population per year.[3] This suggests that less than 0.2%
people with a retinal break eventually have a detachment of the retina.
This value may be higher in patients with a symptomatic posterior vitreous
detachment; however it is reasonable to conclude that only a minority of
retinal breaks will go on to cause a retinal detachment. Prophylactic
treatment of retinal breaks by laser or cryotherapy is not without
complications; also detachments can occur in eyes that have had
prophylactic treatment.[4] Byer has reported that retinal breaks in
unoperated eyes with posterior vitreous detachment can be followed up
without treatment, with only a minority progressing to retinal
detachments.[5]
We have a test that has a negative predictive value of 99%. We know that
only a minority of patients who have a retinal tear or hole actually
benefit from prophylactic treatment. Can we still justify referring all
patients with a posterior vitreous detachment and no vitreous pigment for
a specialist examination or even a follow-up examination in the light of
this knowledge?
The appropriate recommendation would be that all patients presenting with
posterior vitreous detachment, no vitreous pigment and no retinal tears or
holes at initial examination can be safely discharged with an explanation
of the warning symptoms which should prompt the patient to return to the
ophthalmologist.
References
1. Byer NE. Clinical study of retinal breaks. Trans Am Acad Ophthalmol
Otolaryngol 1967;71:461-73.
2. Foos RY. Posterior vitreous detachment. Trans Am Acad Ophthalmol
Otolaryngol 1972;76:480-97.
3. Haiman MH, Burton TC, Brown CK. Epidemiology of retinal detachment.
Arch Ophthalmol 1982;100:289-92.
4. Schroeder W, Baden H. Retinal detachment despite preventive
coagulation. Ophthalmologe 1996;93:144-8.
5. Byer NE. What happens to untreated asymptomatic retinal breaks, and
are they affected by posterior vitreous detachment? Ophthalmology
1998;105:1045-9.
Editor,
With great interest we read the case report by Dr. Alwitry on "Vitamin A
deficiency in coeliac disease", which raises the question whether a
deficiency of vitamin A with subsequent keratomalacia may be caused by
this disorder. However, although coeliac disease cannot be excluded as a
cause of reduced vitamin A absorption,[1] Alwitry's report does not
convincingly show that the vitamin A deficie...
Editor,
With great interest we read the case report by Dr. Alwitry on "Vitamin A
deficiency in coeliac disease", which raises the question whether a
deficiency of vitamin A with subsequent keratomalacia may be caused by
this disorder. However, although coeliac disease cannot be excluded as a
cause of reduced vitamin A absorption,[1] Alwitry's report does not
convincingly show that the vitamin A deficiency in his patient was indeed
due to this disease. If, as was stated in the letter, the patient really
had been on a gluten-free diet, his diarrhoea - and probably related
vitamin A malabsorption - may well have had other causes; e.g., fat
maldigestion, mostly resulting from hepatic and/or pancreatic disorders.
In addition, it is not known whether Alwitry's patient received enough
dietary fat and (with it) vitamin A. Furthermore, Alwitry refers to the
report by Sommer et al[2] for the statement "supplementation via the oral
or intramuscular route, each of which have been demonstrated to be equally
efficacious." Sommer's article, however, deals with Indonesian children
with xerophthalmia, and not with patients with coeliac disease. This
should be considered, if different administration regimens of vitamin A
are compared. In agreement with Sommer's work, additional determination
of serum retinol-binding protein (RBP) would result in a more
comprehensive view of the patient's vitamin A status. In this context a
further criticism of Alwitry's contribution is that only a single serum
vitamin A value is presented and that the corresponding concentration unit
as well as sufficient information on the time of sampling in relation to
vitamin A administration are not given.
References
1. Johnson EJ, Krasinski SD, Howard LJ, et al. Evaluation of vitamin A
absorption by using oil-soluble and water-miscible vitamin A preparations
in normal adults and in patients with gastrointestinal disease. Am J Clin
Nutr 1992;55:857-64.
2. Sommer A, Muhilal, Tarwotjo I, et al. Oral versus intramuscular
vitamin A in the treatment of xerophthalmia. Lancet 1980;1:557-9.
Editor, I read the article by Bechmann et al with interest, and I
congratulate the authors on their work. In the discussion, they cover the
entire subject of tonometry on the basis of the central corneal thickness
(CCT). With the increasing number of corneal refractive procedures
performed every year, this point will be associated with much uncertainty
for diagnosing glaucoma in the near future. Appare...
Editor, I read the article by Bechmann et al with interest, and I
congratulate the authors on their work. In the discussion, they cover the
entire subject of tonometry on the basis of the central corneal thickness
(CCT). With the increasing number of corneal refractive procedures
performed every year, this point will be associated with much uncertainty
for diagnosing glaucoma in the near future. Apparently, ophthalmologists
are slowly becoming aware of this problem.[1]
In their conclusion, the authors emphasize the "need for a combined
measurement of IOP and CCT in order to be able to classify the different
types of glaucoma." There is, as we perceive it, a slight
misunderstanding of the problem. The Goldmann tonometer[2] measures the
force required for flattening the cornea. From this, it concludes the
pressure in the eye. From the original article of Goldmann, it is well
known that this relationship is only valid for a corneal thickness of
roughly 520 micrometers. However, the problem is not the thickness itself
of the cornea, but rather the cornea's biomechanical properties (e.g.,
elasticity), which are somehow related to its thickness. Thus, a better
solution for this problem would be a measurement of the eye pressure that
was independent of the thickness. In this case, each eye could be
measured correctly irrespective of the biomechanical properties of the
cornea. With the contact lens tonometer, now called SmartLens®, we have
been able to demonstrate that after LASIK the true IOP can be measured,[3]
thereby excluding any possible false negative glaucoma cases. The
SmartLens® tonometer directly measures the pressure in the middle of the
applanated area and, therefore, is independent of any corneal property,
including its thickness.[4] To the best of our knowledge, this is the only
way to prevent the ophthalmologist from possible incorrect diagnosis and
follow-up of glaucoma patients in the future.
1. Lewis, RA. Refractive surgery and the glaucoma patient (customized
corneas under pressure). Ophthalmology 2000;107(9):1621-1622.
2. Goldmann, H, Schmidt TH. Über Applanationstonometrie Ophthalmologica.
1957;134:221-241.
3. Kaufmann C, Schipper I, Robert YCA. SmartLens® Tonometry compared to
Goldmann Tonometry before and after Refractive Surgery. Invest Ophthalmol
Vis Sci 2000;41(4):S598. Abstract #2475.
4. Dekker PW, Robert YCA, Kanngiesser H, Pirani P, Entenmann B.
Principles of contact lens tonometry. International Ophthalmol
1999;22:105-111.
Dear Sir,
In India, we very commonly see mature cataracts. Doing capsulorhexis with
injection of dye is done very routinely by many of us. Forunately no
untoward reaction has been reported so far. This helps us to carry out the
phaco procedure with ease.
Dear Sir,
I was fascinated by Cheng and colleagues' article on Mooren's ulcer
in China. During the past 6 years I have worked for 3 years as an
ophthalmologist in rural Cameroun. I submit to you my experiences of
Mooren's ulcer there :
Patients: 5 (4 male, 1 female). Age: 1 patient aged 48 years, the rest all late teens and twenties.
Dear Sir,
I was fascinated by Cheng and colleagues' article on Mooren's ulcer
in China. During the past 6 years I have worked for 3 years as an
ophthalmologist in rural Cameroun. I submit to you my experiences of
Mooren's ulcer there :
Patients: 5 (4 male, 1 female). Age: 1 patient aged 48 years, the rest all late teens and twenties.
Out of 3 patients we tested (following a histology report on excised
conjunctiva), 2 had positive skin-snips for Onchocerca volvulus. None of
the predisposing factors referred to in Cheng's article applied to any of
these patients.
All ulcers were unilateral, and totally resistant to any medical
treatment that was available (topical prednisolone sodium phosphate 1%,
oral cyclophosphamide). I tried various surgical treatments and found that
the only one that gave satisfactory results was excision of a 3 mm-wide
band of conjunctiva next to the ulcer, and covering the ulcer and bared
sclera with a free conjunctival graft (conjunctival flaps simply retracted
and separated), followed by chloramphenicol and prednisolone drops for a
month. This became my first-line treatment. Corneal grafting was not
a possibility. One ulcer recurred by circumferential extension from the
original site.
Editor,
Trichiasis is a posterior misdirection of eyelashes. Due to constant corneal irritation it can give rise to discomfort, recurrent infection, corneal ulceration and pannus formation. Several modalities of treatment exist which include epilation, electrolysis, cryotherapy and argon laser thermoablation.[1] [2] Argon laser offers the advantage of being a relatively simple, virtually painless met...
Editor,
It is pleasing to see Tole et al[1] having success with impression cytology (IC) in the diagnosis of ocular surface squamous neoplasia (OSSN) and we thank the authors for their acknowledgment of our work.
We continue to use the small cellulose acetate strips because they offer greater sampling flexibility. However, the Biopore membrane could have practical advantages if samples are to be colle...
Editor,
We read with interest the article by Valmaggia et al[1] who studied OKN in patients with macular degeneration. They noted abnormalities of OKN gain only in patients with large central scotomas. Therefore an intact macula seems not to be necessary for the generation of OKN. This implicitly suggests an important role of the peripheral retina in eliciting an OKN. In this context, it is interes...
Editor,
I read the article by Schlote et al with interest. The aim of their study was to determine the safety and effectiveness of transscleral diode laser cyclophotocoagulation (TDLC) in post inflammatory eyes with refractory glaucoma. In addition, the authors have rightly pointed out that management of inflammatory glaucoma is still a dilemma as many of the antiglaucoma drugs are either contraindica...
Editor,
We would like to congratulate Heimann and colleagues for their study on 21 patients presenting with retinal vasoproliferative tumours treated by cryotherapy, brachytherapy or enucleation. We wonder whether an intravitreal injection of crystalline cortisone, as single procedure or in combination with the strategies described by the authors' study, may be an additional option in the therapeutic...
Editor,
We read Tanner et al's paper on the predictive value of vitreous pigment (Schaffer's sign) for retinal breaks in posterior vitreous detachment1 with great interest. Based on their figures, patients who have a negative Schaffer's sign had a 1% chance of having a retinal tear or hole and a 0.5% chance of having a lesion for which prophylaxis was thought to be appropriate. Thus Schaffer's sign ha...
Editor,
With great interest we read the case report by Dr. Alwitry on "Vitamin A deficiency in coeliac disease", which raises the question whether a deficiency of vitamin A with subsequent keratomalacia may be caused by this disorder. However, although coeliac disease cannot be excluded as a cause of reduced vitamin A absorption,[1] Alwitry's report does not convincingly show that the vitamin A deficie...
Editor,
I read the article by Bechmann et al with interest, and I congratulate the authors on their work. In the discussion, they cover the entire subject of tonometry on the basis of the central corneal thickness (CCT). With the increasing number of corneal refractive procedures performed every year, this point will be associated with much uncertainty for diagnosing glaucoma in the near future. Appare...
Dear Sir,
In India, we very commonly see mature cataracts. Doing capsulorhexis with injection of dye is done very routinely by many of us. Forunately no untoward reaction has been reported so far. This helps us to carry out the phaco procedure with ease.
Dear Sir,
I was fascinated by Cheng and colleagues' article on Mooren's ulcer in China. During the past 6 years I have worked for 3 years as an ophthalmologist in rural Cameroun. I submit to you my experiences of Mooren's ulcer there :
Patients: 5 (4 male, 1 female).
Age: 1 patient aged 48 years, the rest all late teens and twenties.
Out of 3 patients we tested (foll...
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