Dear Editor,
we have read with great interest the article of Skoloudik and coworkers on
the use of optic nerve ultrasonography in patients with intracranial
hemorrhage (ICH). The primary goal of this study was to investigate the
variations of the optic nerve sheath diameter (ONSD) early after the onset
of ICH. The authors should be commended for pointing out our interest
towards a new parameter (the relative difference be...
Dear Editor,
we have read with great interest the article of Skoloudik and coworkers on
the use of optic nerve ultrasonography in patients with intracranial
hemorrhage (ICH). The primary goal of this study was to investigate the
variations of the optic nerve sheath diameter (ONSD) early after the onset
of ICH. The authors should be commended for pointing out our interest
towards a new parameter (the relative difference between the ONSD measured
3 mm and 12 mm behind the optic disc), which proved to be more sensitive
than the absolute ONSD measurement as a predictor of elevated intracranial
pressure (EICP). However, we would like to outline two important
limitations of the study.
1. The use of CT scan imaging as the standard criterion to assess EICP is
relatively non-specific as patients with similar pictures may have
significantly different levels of ICP depending on several concurrent
factors (e.g. Sedation, hyperosmolar therapy, ventilation, intracranial
compliance). Moreover, although the resistance index in the MCA, as
measured with TCDS, is often related to ICP, it cannot discriminate
between EICP and cerebral vasospasm (1,2).
2. When considering the ONSD relative enlargement, which is a
submillimetric value, one should take the error of measurement into
account. Specifically, the current study finds a 95th percentile of ONSD
relative enlargement of 0.22 mm in healty volunteers, which is below the
median interobserver ONSD difference of other studies (3). Furthermore, to
the best of our knowledge, no previous study has systematically
investigated the ONSD interobserver variability 12 mm behind the globe.
Finally, previous studies have found that, unlike the oedema of the optic
disc, the retrobulbar ONSD is a dynamic parameter which varies almost
concurrently with changes in cerebrospinal fluid pressure (4,5).
Therefore, it is not surprising that the retrobulbar ONSD and its derived
parameters are changed in the hyperacute phase of ICH.
1. Stocchetti N. Could intracranial pressure in traumatic brain
injury be measured or predicted noninvasively? Almost. Intensive Care Med
2007;33:1682-3
2. Rasulo FA, De Peri E, Lavinio A. Transcranial Doppler ultrasonography
in intensive care. Eur J Anaesthesiol Suppl. 2008;42:167-73
3. Shah S, Kimberly H, Marill K, Noble VE. Ultrasound techniques to
measure the optic nerve sheath: is a specialized probe necessary? Med Sci
Monit 2009;15/5):MT63-8
4. Hansen HC, Helmke K. Validation of the optic nerve sheath response to
changing cerebrospinal fluid pressure: ultrasound findings during
intrathecal infusion tests. J Neurosurg 1997;87:34-40
5. Moretti R, Pizzi B, Cassini F, Vivaldi N. Reliability of optic nerve
ultrasound for the evaluation of patients with spontaneous intracranial
hemorrhage. Neurocrit Care 2009;11:406-10
Editor, I read the recent publication by Awan et al. with a great
interest [1]. Awan et al. concluded that "As compliance has been
identified as a major problem methods to improve amblyopia treatment are
needed, possibly by using educational/motivational intervention [1]."
Recently, Lee et al. proposed that
"Poor compliance with occlusion therapy was less likely to achieve
successful outcome [2]." Indeed, "how complianc...
Editor, I read the recent publication by Awan et al. with a great
interest [1]. Awan et al. concluded that "As compliance has been
identified as a major problem methods to improve amblyopia treatment are
needed, possibly by using educational/motivational intervention [1]."
Recently, Lee et al. proposed that
"Poor compliance with occlusion therapy was less likely to achieve
successful outcome [2]." Indeed, "how compliance can be enhanced" is the
topic to be discussed in management of amblyopia [3]. I have a question
whether the using of educational interventional will be successful. As a
simple process without long period for educational session, the compliance
is still low. How can we expect on the additional process? Karlica et al.
recently noted that "Frequent ophthalmologic follow ups are mandatory to
be sure that therapy is performed correctly and to prevent the possible
unfavorable effects of noncompliance [4]."
References
1. Awan M, Proudlock FA, Grosvenor D, Choudhuri I, Sarvanananthan N,
Gottlob I. An audit of the outcome of amblyopia treatment: a retrospective
analysis of 322 children. Br J Ophthalmol. 2010 Aug;94(8):1007-11.
2.Lee CE, Lee YC, Lee SY. Factors influencing the prevalence of amblyopia
in children with anisometropia. Korean J Ophthalmol. 2010 Aug;24(4):225-9.
3. Holmes JM, Repka MX, Kraker RT, Clarke MP. The treatment of amblyopia.
Strabismus. 2006 Mar;14(1):37-42.
4. Karlica D, MatijeviÃÆ’ƒÃ¢Â€ÂžÃƒÃ†’‚‡ S, GaletoviÃÆ’ƒÃ¢Â€ÂžÃƒÃ†’‚‡
D, Znaor L. Parents' influence on the treatment of amblyopia in children.
Acta Clin Croat. 2009 Sep;48(4):427-31.
Dear Editor,
We thank Authors S.C. Carroll et al for their interesting paper on the
Outcomes of orbital blowout fracture surgery in children and adolescents.1
We agree that autonomic symptoms of nausea and vomiting should alert the
clinician to the high likelihood of significant orbital trauma. This
study shows that the overall outcomes for all patients under the age of 20
were good despite delays. However, this is a hete...
Dear Editor,
We thank Authors S.C. Carroll et al for their interesting paper on the
Outcomes of orbital blowout fracture surgery in children and adolescents.1
We agree that autonomic symptoms of nausea and vomiting should alert the
clinician to the high likelihood of significant orbital trauma. This
study shows that the overall outcomes for all patients under the age of 20
were good despite delays. However, this is a heterogeneous group of
patients with orbital floor fractures with and without entrapment. We are
concerned that young patients with muscle entrapment (white eye blow out
fracture) who are at risk of ischemia are not being highlighted in this
paper.
The data in this series does support early intervention for the two
subgroups of trapdoor fractures. These groups included 6 patients with
open trapdoor fractures and 6 patients with linear closed trapdoor and in
which there is a greater risk of presumed muscle ischemia and poorer
outcome. Follow up data was only available for 4 of the 6 linear closed
trapdoor fractures, all of whom received their surgical intervention
within 2 weeks (2 within 2 days); the one that fully recovered did not
have entrapment of their inferior rectus in the fracture and the other 3
were left with residual diplopia in extreme gaze. Those patients with open
trapdoor fractures all had surgery within 8 days and all but 1 regained
full ductions but not all were symptom free. As per your comments in the
discussion, the depressed plate fractures are lower risk and indeed did
have good outcomes despite delayed surgery. In fact, in this series the
significant delays were in this patient group and the trapdoor fractures
were all operated on within 2 weeks.
Previous studies have shown that intervention within 14 days results in
complete recovery of supraductions 2. More recent studies have shown
intervention within 7 days3 or within 24 hours4 also gives complete
resolution of any symptoms of diplopia.
We, therefore, feel it important to highlight that your data does support
intervention for trapdoor fractures within 2 weeks (median 4 days) and we
feel it is possible that some of these patients may have been completely
symptom free if operated on earlier. We would encourage colleagues to
operate on these patients as soon as possible to not only maximise
potential recovery but also to alleviate any vagal symptoms.
1. Carroll SC, Ng SGJ. Outcomes of orbital blowout fracture surgery
in children and adolescents. Br J Ophthalmol 2010; 94: 736-739
2. Bansagi ZC, Meyer DR. Internal orbital fractures in the pediatric
age group: characterization and management. Ophthalmology 2000; 107(5):
829-836.
3. Ethunandan M, Evans BT. Linear trapdoor or "white-eye" blowout
fracture of the orbit: not restricted to children Br J Oral Maxillofac
Surg. 2010 May 12. [Epub ahead of print]
4. Gerbino G et al. Surgical Management of Orbital Trapdoor Fracture
in Pediatric Population. J Oral Maxillofac Surg 2010; 68: 1310-1316.
We congratulate Salowi and colleagues on their study of the use of
CUSUM to monitor competency in cataract extraction (1). However there are
two modifications that could make their system more responsive and
reliable.
Firstly the authors use a CUSUM chart that fluctuates on only one
side of the zero line. Traditionally CUSUM charts fluctuate on both sides
of the zero line (2,3). The consultant in their Figure 1...
We congratulate Salowi and colleagues on their study of the use of
CUSUM to monitor competency in cataract extraction (1). However there are
two modifications that could make their system more responsive and
reliable.
Firstly the authors use a CUSUM chart that fluctuates on only one
side of the zero line. Traditionally CUSUM charts fluctuate on both sides
of the zero line (2,3). The consultant in their Figure 1 performed 48
procedures and 43 were successful while 5 were failures. The weight for a
failure would be -1.791666 and for a success it would be 0.208333.
Figure 1 depicts the traditional CUSUM graph with this data. Against this,
the data from his trainee is also drawn. The trainee CUSUM score keeps
going further and further away from the zero line, suggesting that he has
not reached the bottom of his learning curve. Once his learning is over,
his mean CUSUM line will run parallel to the zero line.
The second modification relates to the decision interval. The authors
discuss in detail the arbitrary decision intervals (control lines) that
they have employed, based on a trade-off between the need to detect poor
performance quickly and that to avoid a large number of false alarms.
Decision lines need not be arbitrary. With the help of computers,
bootstrapping techniques can be employed, so that these lines are placed
where they are statistically meaningful. As an illustration, in Figure 1
with the consultant performance, there were 5 failures and 43 successes.
The 5 failures need not be evenly interspersed among the successes. The
sequence of failures is purely a matter of chance and 2 or even 3 failures
may be clustered together. Bootstrapping allows random reordering of the
failures and successes in a way that the overall numbers of success and
failures are the same for each iteration. The computer can calculate the
maximum and minimum score for each iteration. If a 1000 iterations are
performed it is possible to calculate the mean of the highest scores
(maximum score in the iteration) and the mean of the lowest scores
(minimum score in the iteration) and also the standard deviation around
the means. The upper decision line is the limit drawn with the mean upper
score plus 2SD. The lower decision line is the mean lower score minus 2SD.
If surgery is performed by a person of comparable competence as the
consultant, his CUSUM score will lie within the two decision lines, 95% of
the time.
We have recently used CUSUM for a clinical trial and for this we
developed software that allows for easy bootstrapping, drawing of control
lines and plotting of CUSUM score. This software is available free on the
internet. (http://jacob.puliyel.com/foresee/).
Figure 2 can also be redrawn using the acceptable rate for posterior
capsule rupture (PCR) of 5%. Here the acceptable standard is 1 failure for
19 successes. For Figure 3 using the acceptable rate for impaired vision
as 10% (using data reported by the authors from the Malaysian National
Cataract Surgery Registry) there can be 1 failure for 9 successes.
The software is interactive and allows CUSUM plotting in real time
(meaning that it allows one to see how the CUSUM graph evolves, with each
new success or failure). We hope that the free software available on the
net will encourage more widespread use of CUSUM in various clinical
situations.
Figure 1 Standard reference cumulative sum (CUSUM) showing
performance by a trainee and a consultant can be viewed at
http://jacob.puliyel.com/#paper_199
Reference
1. Salowi MA, Choong YF, Goh PP, Ismail M, Lim TO. CUSUM: a dynamic
tool for monitoring competency in cataract surgery performance. Br J
Ophthalmol. 2010;94:445-9.
2. Van Rij AM, McDonald JR, Pettigrew RA, Putterill MJ, Reddy CK,
Wright JJ. Cusum as an aid to early assessment of the surgical trainee. Br
J Surg. 1995;82:1500-3.
3. Sibanda T, Sibanda N. The CUSUM chart method as a tool for
continuous monitoring of clinical outcomes using routinely collected data.
BMC Med Res Methodol. 2007;7:46.
Ashish Puliyel, Tech Guru gonzoBuzz, Singapore
ashishpuliyel@gmail.com
Jacob Puliyel, Consultant Pediatrician, St Stephens Hospital, Delhi, India
puliyel@gmail.com
Conflict of Interest:
The CUSUM software available free on the internet, was developed by the authors in the context of a clinical trial.
One concept of the PEARS/ WEHE schemes was to increase equity of
access to eye care services across Wales. Any successful scheme which
achieves an increase in access will increase cost, at least in the short-
term, but can prove to be more cost-effective since more expensive
downstream-treatments are avoided as a result of earlier intervention and
patient outcomes are likely...
One concept of the PEARS/ WEHE schemes was to increase equity of
access to eye care services across Wales. Any successful scheme which
achieves an increase in access will increase cost, at least in the short-
term, but can prove to be more cost-effective since more expensive
downstream-treatments are avoided as a result of earlier intervention and
patient outcomes are likely to be enhanced.
Purchasers must judge whether improved access for patients justifies the small additional cost per case (c. £12-15) and improved access results in more patients being seen in secondary care. In the evaluation, 66% of patients were managed entirely by optometrists without referral to the Hospital Eye Service (HES): previously, these patients may have contributed to unnecessary referrals. Other benefits for patients include convenience, reduced travel time, reduced anxiety and fewer mis-diagnoses.
The change in total cost of primary and secondary eye care following the introduction of these schemes was not quantified. This would have required a randomised protocol comparing costs between intervention and control groups and incorporating a before and after design to capture detailed patient-level data.
Optometrists registered on the schemes at the time of the evaluation had completed seven distance learning modules, four case history scenarios and a clinical-skills assessment. We utilised the results of the evaluation to determine the nature of the re-accreditation training. Optometrists were required to complete six distance learning modules and pass OSCE assessments based on communication, clinical examination and referral. Tutorials were held for those optometrists, identified in the evaluation, who had made inappropriate patient-management decisions. The current cost of training for accreditation is approximately £200 per optometrist. The impact of this one-off cost is minimal given the number of patients seen under the scheme and was therefore not included in the model.
We hope these comments have further clarified patient-centred
benefits of the schemes.
The Primary Eyecare Acute Referral Scheme, PEARS was introduced in
Wales in in 2003. We welcome the paper by Sheen et al since this presents
an opportunity for the scheme to be appraised and costed.
The authors are open about the weaknesses of their study, such as the
poor response rate to letters sent to GPs. However, there are still
considerable uncertainties about the accuracy of the costings....
The Primary Eyecare Acute Referral Scheme, PEARS was introduced in
Wales in in 2003. We welcome the paper by Sheen et al since this presents
an opportunity for the scheme to be appraised and costed.
The authors are open about the weaknesses of their study, such as the
poor response rate to letters sent to GPs. However, there are still
considerable uncertainties about the accuracy of the costings. It is
likely that the provision of this service will have generated an increase
in the number of patients seen in ophthalmic primary care and a consequent
increase in the number of referrals to the HES thereby increasing costs.
No data is presented in this respect although this could have been sought
from GP or hospital databases.
The authors conclude that the net cost of the scheme is between 10GBP
and 15GBP per patient. What is not made sufficiently clear is that this
is ADDITIONAL cost to the purchaser. PCTs should be discouraged from
implementing this service without first identifying extra funding. It
should not be expected that this service can be paid for from savings made
in the budgets of ophthalmic units.
No mention is made of the training required before optometrists can
embark upon this scheme. It would have been helpful for those considering
such a scheme to have some idea of the nature of and the costs of such
training.
Yours faithfully,
Simon Longstaff
Chairman
Ophthalmic Group Committee
Conflict of Interest:
I am the chairman of the Ophthalmic Group Committee
Dear Editor, we have read with great interest the article of Skoloudik and coworkers on the use of optic nerve ultrasonography in patients with intracranial hemorrhage (ICH). The primary goal of this study was to investigate the variations of the optic nerve sheath diameter (ONSD) early after the onset of ICH. The authors should be commended for pointing out our interest towards a new parameter (the relative difference be...
Editor, I read the recent publication by Awan et al. with a great interest [1]. Awan et al. concluded that "As compliance has been identified as a major problem methods to improve amblyopia treatment are needed, possibly by using educational/motivational intervention [1]." Recently, Lee et al. proposed that "Poor compliance with occlusion therapy was less likely to achieve successful outcome [2]." Indeed, "how complianc...
Dear Editor, We thank Authors S.C. Carroll et al for their interesting paper on the Outcomes of orbital blowout fracture surgery in children and adolescents.1 We agree that autonomic symptoms of nausea and vomiting should alert the clinician to the high likelihood of significant orbital trauma. This study shows that the overall outcomes for all patients under the age of 20 were good despite delays. However, this is a hete...
We congratulate Salowi and colleagues on their study of the use of CUSUM to monitor competency in cataract extraction (1). However there are two modifications that could make their system more responsive and reliable.
Firstly the authors use a CUSUM chart that fluctuates on only one side of the zero line. Traditionally CUSUM charts fluctuate on both sides of the zero line (2,3). The consultant in their Figure 1...
Authors response
Dear Sir,
One concept of the PEARS/ WEHE schemes was to increase equity of access to eye care services across Wales. Any successful scheme which achieves an increase in access will increase cost, at least in the short- term, but can prove to be more cost-effective since more expensive downstream-treatments are avoided as a result of earlier intervention and patient outcomes are likely...
Sir,
The Primary Eyecare Acute Referral Scheme, PEARS was introduced in Wales in in 2003. We welcome the paper by Sheen et al since this presents an opportunity for the scheme to be appraised and costed.
The authors are open about the weaknesses of their study, such as the poor response rate to letters sent to GPs. However, there are still considerable uncertainties about the accuracy of the costings....
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