We would like to give a response to the letter of Dr. Anshuman
Sinha concerning our article "23 Gauge versus 20 Gauge System for Pars
Plana Vitrectomy: A Prospective Randomized Clinical Trial".
For analysis of postoperative pain we used a simplified verbal
rating scale (ranging from 0, meaning no pain, to 3, meaning severe
pain). The standardized verbal rating scale reaches from 0 (no pain) to...
We would like to give a response to the letter of Dr. Anshuman
Sinha concerning our article "23 Gauge versus 20 Gauge System for Pars
Plana Vitrectomy: A Prospective Randomized Clinical Trial".
For analysis of postoperative pain we used a simplified verbal
rating scale (ranging from 0, meaning no pain, to 3, meaning severe
pain). The standardized verbal rating scale reaches from 0 (no pain) to
10 ("the worst pain possible"), which we think is too extensive for our
patients and purpose.
In literature verbal rating scales are described to be a valid, reliable
and appropriate tool for determination of postoperative pain in clinical
practice [1,2] Furthermore we believe that the assessment of
postoperative pain is not likely to be biased if the assessor is not
masked, because the perception of pain is a completely subjective
parameter.
Regarding the sample size evaluation: The effect size was assumed
to be 75% of the standard deviation and the power to be 80%. These
assumptions were extrapolated from the observations of our previous
study [3]. Unfortunately, this information had been dropped from a
previous version of the manuscript for brevity.
It is well known that studies with single surgeons have better
results than with multiple surgeons. On the other hand, it is
recommended to choose a realistic situation to achieve more realistic
results. Our surgeons were randomized and there was a general surgical
protocol to be followed. This also is the reason why we used two
different vitrectomy machines. Both of them work in a comparable way and
the settings were preset and the same in both machines.
We agree, that the lens status has an influence on the amount of
vitreous removed and that an intraocular tamponade influences
postoperative eye pressure. However, both factors were equally
distributed in both surgical groups and therefore have no influence on
the results.
Concerning the way of suturing the 20 gauge wounds, this was done the
same way in all patients using vicryl 7.0 sutures as described in the
methods section.
A summary of nominal categorical data would have to be done by
contingency tables and neither by mean nor by median and interquartile
range. Since the data mentioned are not of nominal but ordinal nature,
we assume that the author of this letter refers to ordinal data. We have
to note that the summary presented in table 2 was done for the area
under the curve (AUC) for the conjunctival injection and postoperative
pain measured at days 0, 1, 2, 3, one week, one month and three months
after surgery as indicated in figures 1 and 2. Although theses
measurements are, strictly speaking, still of ordinal nature they have a
large range of values (see table 2) and hence can be treated as metric
variables. Moreover, it is common practice to summarize AUCs by mean and
standard deviation. We also note that in a previous version of the paper
we have given in addition to the mean and standard deviation also the
median, first and third quartile. Unfortunately, these numbers as well
as the information in the text that the AUCs are summarized have been
omitted in the edited manuscript.
We furthermore agree that each complication represents a serious
situation. However, from the data of our study we can not conclude that
a clear indication for higher risk is given using 23 gauge vitrectomy.
This question remains open and a larger prospective randomized study is
needed to get a clear result of the safety of 23 gauge surgery. Since
the data do not indicate a difference in the development of serious
complications between the two treatment groups we made the cited careful
assertion "seems to be a safe system".
Regarding the Consolidated Standards for Reporting Trials (CONSORT)
statement [4], we certainly know and appreciate this publication and
followed these recommendations. Moreover, our article represents the
only prospective randomized study concerning this topic.
We do appreciate your considerations, but we strongly believe that we
have performed a well-designed study. Still, there are always things
that can be improved.
References
1.Williamson A, Hoggart B. Pain: a review of three commonly used
pain rating scales. J Clin Nurs. 2005 Aug;14(7):798-804.
2.Randall C. Cork, Ihab Isaac, Ahmad Elsharydah, Sarosh Saleemi,
Frank Zavisca and Lori Alexander: A comparison of the verbal rating
scale and the visual analog scale for pain assessment. The Internet
Journal of Anesthesiology. 2004: Volume 8, Number1.
3.Kellner L, Wimpissinger B, Stolba U, Brannath W, Binder S.
25-gauge vs 20-gauge system for pars plana vitrectomy: a prospective
randomised clinical trial. Br J Ophthalmol. 2007 Jul;91(7):945-8.
4.Moher D, Schulz KF, Altman DG. The CONSORT statement: revised
recommendations for improving the quality of reports of parallel-group
randomised trials. Lancet 2001;357:1191-4.
American pediatricians, armed with a new reimbursement code for
photoscreening young children (99174), are very interested in the validity
of
potential instruments. As such, we were interested in the recent report
that
compared Plusoptix photoscreener to orthoptic exam in early primary school
children, reporting 100% specificity but relatively low sensitivity: “the
sensitivity of the PVS to detect
amblyopia-associated f...
American pediatricians, armed with a new reimbursement code for
photoscreening young children (99174), are very interested in the validity
of
potential instruments. As such, we were interested in the recent report
that
compared Plusoptix photoscreener to orthoptic exam in early primary school
children, reporting 100% specificity but relatively low sensitivity: “the
sensitivity of the PVS to detect
amblyopia-associated factors is 44%, with 95% CI from 28 to 62%. Even a
sensitivity of
62% would be less than desirable for a standalone screening test”[1] We are
concerned the methodology and terminology for “sensitivity” differs from
what many pediatricians might expect.
From Table 3, it appears the PlusOptix was able to detect most refractive
errors but underestimated cycloplegic hyperopia and strabismus. We ask
that
the authors report their results by using pre-defined pediatric
ophthalmology
risk levels (ref 10) and clarify the limited number of their subject who
actually
completed the cycloplegic examination which others consider the gold
standard[2].
Plusoptix allows users to pre-define age-based referral cut offs for
various
amblyopia risk factors. We wonder why the authors chose their PlusOptix
cutoffs that differed from an attempt to calibrate the instrument in
reference
21?[3] Furthermore we wonder if changing the cutoff for hyperopia may
increase the accuracy of the device. It may be worthwhile to re-analyze
this
original cohort to see if the sensitivity would improve. It would also be
worth
noting how the gold standard orthoptic vision screening compares to a
dilated cyclopleged examination by a pediatric ophthalmologist, as
comparing the Plusoptix to a comprehensive ophthalmology examination
may change the reliability. Orthoptists are ideally trained to provide an
accurate pediatric vision screening on children, however in certain
countries,
such as the United States of America, with a population of approximately
305
million people and only approximately 300 orthoptists more efficient
methods of pediatric vision screenings must be discovered and refined.
In recent population studies the prevalence of childhood amblyopia,
primarily
comprised of refractive error and manifest esotropia, is about 2.5%[4]. If
an
acceptable screening technique has false positive rate less than 1/3, then
the
ideal referral rate should be about 4%, much closer to the PlusOptix
compared to 12.5% for orthoptic screening. The author’s “gold standard”
orthoptic screening has merit, but probably has low predictive value for
amblyopia screening.
Robert W. Arnold, MD
Noelle Matta CO, CRC, COT, Orthoptist
Members of the Vision Screening Committee of AAPOS
References
1. Dahlmann-Noor A, Vrotsou K, Kostakis V, et al. Vision
screening in
Children by Plusoptix Vision Screener compared with gold standard
orthoptic
assessment. Br J Ophthalmol 2008;92:e-pub.
2. Donahue S, Arnold R, Ruben JB. Preschool vision screening:
What
should we be detecting and how should we report it? Uniform guidelines
for
reporting results from studies of preschool vision screening. J AAPOS
2003;7:314-6.
3. Clausen MM, Arnold RW. Pediatric Eye/Vision Screening:
Referral
Criteria for the PediaVision PlusOptix S04 Photoscreener Compared to
Visual
Acuity & Digital Photoscreening: “Kindergarten Computer
Photoscreening”.
Binoc Vis and Strabismus Quart 2007;22:83-9.
4. MEPEDS. Prevalence of amblyopia and strabismus in African
American and Hispanic children ages 6 to 72 months the multi-ethnic
pediatric eye disease study. Ophthalmology 2008;115:1229-36 e1.
We read with interest the paper by Wimpissinger et al comparing
sutureless 23-gauge system to a standard 20-gauge system for pars plana
vitrectomy, in a randomized clinical trial.[1] We aim to highlight a few
issues in the design, methodology and analysis.
The authors have analysed postoperative pain and conjunctival
injection as primary outcome measures. The effort by the assessor to
elicit a...
We read with interest the paper by Wimpissinger et al comparing
sutureless 23-gauge system to a standard 20-gauge system for pars plana
vitrectomy, in a randomized clinical trial.[1] We aim to highlight a few
issues in the design, methodology and analysis.
The authors have analysed postoperative pain and conjunctival
injection as primary outcome measures. The effort by the assessor to
elicit a response on the degree of pain is likely to be biased if he is
not masked, as in this study. In assessment, the authors have used
descriptive terms like no pain, mild, moderate and severe pain. The
authors could have used other standardized methods described to measure
pain such as numerical scores, faces scale, visual analogue scales and
multidimensional instruments like various questionnaires. Literature in
Ophthalmology has precedence of using a visual analogue scale for
assessment of pain.[2]
The authors determined the sample size by statistical pre-study
evaluation (by two group t-test with a 0.05 two-sided significance
level).
Since the authors have not provided data on effect size (delta), and
power (1-beta), it is not clear how a sample size of 60 with 30 patients
in each arm was arrived at.
The other confounding variable likely to be of significance are the
issues like randomization of 4 surgeons (instead of preferably single
surgeon), use of different machines for 20Ga and 23Ga surgeries,
unspecified cut rates for 20Ga system (likely to influence time of
vitrectomy), the lens status (likely to influence the extent of
vitrectomy possible and aimed at), type of tamponade (likely to
influence postoperative intraocular pressures) and suturing technique of
conjunctiva (likely to influence subjective pain) after 20Ga surgery.
In analysis, nominal type of categorical data (as used for
assessing postoperative pain and conjunctival injection) would have been
better analysed in terms of median and interquartile range rather than
taking their minimum, maximum and average values.
The authors have concluded that "The 23 gauge system seems to be a
safe system suitable for a broad spectrum of vitreoretinal diseases". We
disagree with this conclusion as the data provided shows that 3 (10%,
95% CI -0.74 to 20.74%) patients developed serious complications, 2 of
whom required re-surgery.[1]
An international group developed the Consolidated Standards for
Reporting Trials (CONSORT) statement in an attempt to improve documented
suboptimal reporting of RCTs.[3] In an attempt to further improve the
reporting of RCTs, the same international group published the revised
CONSORT statement in 2001 which outlined a checklist of 22 items.[4]
References
1. B Wimpissinger, L Kellner, W Brannath, K Krepler, U Stolba, C
Mihalics and S Binder. 23-gauge versus 20-gauge system for pars plana
vitrectomy: a prospective randomised clinical trial. Br J Ophthalmol
2008; 92; 1483-1487.
2. Mathew MR, Williams A, Esakowitz L, Webb LA, Murray SB, Bennett
HG. Patient comfort during clear corneal phacoemulsification with sub-
Tenon's local anesthesia. J Cataract Refract Surg 2003 ; 29(6): 1132-6.
3. Begg C, Cho M, Eastwood S, et al. Improving the quality of
reporting of randomized controlled trials. The CONSORT statement. JAMA
1996;276:637-9.
4. Moher D, Schulz KF, Altman DG. The CONSORT statement: revised
recommendations for improving the quality of reports of parallel-group
randomised trials. Lancet 2001;357:1191-4.
I read with interest the recent study by Yi et al.
A very minor point... were the Stratus OCT images obtained using the
"Radial
Lines" protocol or the "Fast Macular Thickness" protocol? From Figure 1, I suspect that the higher resolution Radial Lines protocol was used (and not Fast Macular Thickness as described in the manuscript).
In any event, I commend the authors for a worthwhile addition to the
li...
I read with interest the recent study by Yi et al.
A very minor point... were the Stratus OCT images obtained using the
"Radial
Lines" protocol or the "Fast Macular Thickness" protocol? From Figure 1, I suspect that the higher resolution Radial Lines protocol was used (and not Fast Macular Thickness as described in the manuscript).
In any event, I commend the authors for a worthwhile addition to the
literature.
I read with interest the article by Dr. Cohn, et al regarding the
natural history of
autosomal dominant optic atrophy (DOA). The authors describe an average
of
10-year follow up for 69 patients with genetically confirmed DOA. In
their
study, 6 (9%) patients enjoyed improvement in visual acuity by 2 or more
lines.
I found this surprising, and I wonder if the authors could provide...
I read with interest the article by Dr. Cohn, et al regarding the
natural history of
autosomal dominant optic atrophy (DOA). The authors describe an average
of
10-year follow up for 69 patients with genetically confirmed DOA. In
their
study, 6 (9%) patients enjoyed improvement in visual acuity by 2 or more
lines.
I found this surprising, and I wonder if the authors could provide
further
information regarding this group. Is it the opinion of the authors that
these
patients actually improved or that this may represent testing artifact or
bias?
Were they significantly younger than the rest of the cohort? Was their
follow up
significantly shorter? By how much did the acuities improve among this
group?
Was their baseline acuity more likely to come from outside records?
We are very interested to read Prof Radcliffe’s data showing a variable
IOP rise in different subjects tested with the same goggle design. Their
results, like ours,[1] suggest that individual anatomic or physiologic
factors are important in determining the IOP rise. Currently, these
factors are unknown with significant certainty, however som...
We are very interested to read Prof Radcliffe’s data showing a variable
IOP rise in different subjects tested with the same goggle design. Their
results, like ours,[1] suggest that individual anatomic or physiologic
factors are important in determining the IOP rise. Currently, these
factors are unknown with significant certainty, however some of our
results identified that subjects with reduced orbital area were more prone
to IOP elevation. These results were not confirmed by subsequent
measurement and analysis of a separate cohort.[1] However, it is our
impression that subjects with a flatter orbital profile, without a
prominent orbital brow and with more soft tissue in the anterior orbit are
at greater risk of IOP rise.
We also provide a service to our patients whereby we can test their
IOP response to wearing goggles. We use either a standard set with holes
drilled or their own and drill holes through to enable applanation
tonometry whilst they wear them in the clinic. We agree fully with Prof
Radcliffe that this is a useful service for glaucoma patients and
suspects.
Yours Sincerely
W H Morgan
For W H Morgan, T S Cunneen, C Balaratnasingam and D-Y Yu
Reference
1. Morgan WH, Cunneen TS, Balaratnasingam C, Yu DY. Wearing swimming
goggles can elevate intraocular pressure. British Journal of Ophthalmology
2008;92:1218-21.
We would like to congratulate Drs Morgan and colleagues on their
recent paper “Wearing swimming goggles can elevate intraocular pressure.”
We performed a similar study and presented our data at the Association for
Research in Vision and Ophthalmology in 2007. Our findings demonstrated
that in healthy participants, IOP measurements taken during goggle wear
were significantly higher at both one and five minutes, with an av...
We would like to congratulate Drs Morgan and colleagues on their
recent paper “Wearing swimming goggles can elevate intraocular pressure.”
We performed a similar study and presented our data at the Association for
Research in Vision and Ophthalmology in 2007. Our findings demonstrated
that in healthy participants, IOP measurements taken during goggle wear
were significantly higher at both one and five minutes, with an average
increase of 12.5% or +1.5 mmHg. A small subset of eyes (10%) in our study
had an increase in IOP greater than 5 mmHg at both one and five minutes of
goggle wear. We applaud the use of a predictive model in evaluating which
goggles may be associated with IOP elevation. In our study, utilizing a
single goggle design (Speedo), the IOP did not increase significantly in
40% of subjects but increased over 5mmHg in others. In light of this
variability we have retained our prototype study goggle in order to
measure the goggle-induced IOP effect in our glaucoma patients who wish to
swim. Regularly testing these patients in the office allows us to better
inform our patients of the potential risks of goggle wear during swimming.
We thank Dr. Alm for his interest and comment on our paper entitled
“Practical recommendations for measuring rates of visual field change in
glaucoma.” We agree that the standard error of slope estimates is
dependent
on the number of examinations and duration of follow-up. However, these
two parameters are not interchangeable. As pointed out correctly by Dr.
Alm,
the same number of examinations ov...
We thank Dr. Alm for his interest and comment on our paper entitled
“Practical recommendations for measuring rates of visual field change in
glaucoma.” We agree that the standard error of slope estimates is
dependent
on the number of examinations and duration of follow-up. However, these
two parameters are not interchangeable. As pointed out correctly by Dr.
Alm,
the same number of examinations over a longer time period will lead to a
better slope estimation and therefore greater power simply because the
amount of net change is larger. Hence the difference in follow-up of 3 (27 compared to 24 months) months in his example yields an additional change
of -0.5 dB in Mean Deviation and therefore the number of examinations
derived to obtain equivalent power is not surprising.
The goal of our first recommendation of 6 examinations in the first
two years
was not to determine whether the slope of visual field decay is
statistically
significant or not. It was to identify patients who we feel are
progressing
rapidly. In these patients we do not feel that prolonging the follow-up
is an
adequate substitute for more frequent examinations. Even if equivalent
statistical power is obtained with this approach, prolonging the follow-up comes with the very significant cost of more visual field loss.
Our paper was meant to be an initial guideline for clinicians on what rates of visual field change could be detected (with varying degrees of power) with a
given frequency of examinations. We would like to emphasise that there is a large distinction between detection of progression and determining the
rate of visual field change. Therefore the proposed guidelines are not necessarily
designed to detect progression. We welcome the comments of Dr. Alm and others that encourage us to factor in aspects such as the time-separation
between tests and measures besides Mean Deviation which consider the
location of visual field defects.
Sincerely,
BC Chauhan, DF Garway-Heath, FJ Goñi, L Rossetti, B Bengtsson, AC
Viswanathan and A Heijl
There are many pertinent and interesting observations in your
article. As one of the first few users of PASCAL in India, we have now a
large data-base of patients in a short span of time. Critical to
understanding PASCAL is the fluence. Contrary to what we always thought,
retinal hemorrhages and acoustic damage are not seen at 10 ms pulses if
the fluence is within limits. I wish that PASCAL was also programmed to
fix the flue...
There are many pertinent and interesting observations in your
article. As one of the first few users of PASCAL in India, we have now a
large data-base of patients in a short span of time. Critical to
understanding PASCAL is the fluence. Contrary to what we always thought,
retinal hemorrhages and acoustic damage are not seen at 10 ms pulses if
the fluence is within limits. I wish that PASCAL was also programmed to
fix the fluence level at the beginning of each procedure (titrated for each eye) so that inadvertently fluence does not shoot up when the spot size
is changed. PASCAL has really taken out the sting from PRP.
In the article entitled 'Electrophysiological effects of intravitreal
Avastin (bevacizumab) in the treatment of exudative age-related macular
degeneration (ARMD)' by Karanjia et al (Br J Ophthalmol 2008), the authors
examine the sensitivity of multifocal-electroretinogram (mfERG) at
measuring changes in retinal electrical activity in response to Avastin
treatment for ARMD.
In this interesting paper t...
In the article entitled 'Electrophysiological effects of intravitreal
Avastin (bevacizumab) in the treatment of exudative age-related macular
degeneration (ARMD)' by Karanjia et al (Br J Ophthalmol 2008), the authors
examine the sensitivity of multifocal-electroretinogram (mfERG) at
measuring changes in retinal electrical activity in response to Avastin
treatment for ARMD.
In this interesting paper the authors study the changes of P1 response
amplitude and support that this is the first study to demonstrate a
statistically significant change in retinal electrical activity post-bevacizumab in patients with ARMD.
I would like to draw attention to the authors of this article that in our
prospective study 'Intravitreal use of bevacizumab (Avastin) for
choroidal neovascularization due to ARMD: a preliminary mfERG and OCT
study' by Moschos MM et al (Doc Ophthalmol 2007; 114:37-44) really for
the first time we evaluated the macular function before and after
intravitreal use of Avastin.
In our paper based on the study of 18 eyes, 1 month after treatment the
retinal response density of mfERG really shows an improvement but 3 months
after treatment no difference was found between baseline and 3 months.
Our results show that there are anatomical correlates to support the
concept of disease amelioration 1 month after treatment. This is mainly
the decrease of macular thickness as measured by OCT in an extremely
significant degree (p<0.001) the first month after treatment. On the
contrary the mean visual acuity improved only by 0.03 the first month
after treatment and by 0.02 three months after treatment. On the contrary
the mfERG improvement did not follow the decrease of macular thickness and
is significant only the first month after treatment. These findings show
that the increase of visual acuity, as also the improvement of electrical
responses of the macular area is disproportional to the decrease of
macular thickness. This may be explained by the fact that macular edema
is only a parameter that may affect visual acuity and electrophysiological
responses in the beginning of the disease. Atrophy of the retina,
particularly of the photoreceptors, atrophy of the pigment epithelium and
scarring are all unmeasured variables, which influence vision [1, 2].
References
1. Moschos M, Brouzas D, Apostolopoulos M, et al. Intravitreal use of
bevacizumab (Avastin) for choroidal neovascularization due to ARMD: a
preliminary multifocal-ERG and OCT study. Doc Ophtalmol 2007;114:137-144.
2. Moschos M, Panayotidis D, Theodossiadis G, et al. Assessment of macular
function by electroretinography in age-related macular degeneration before
and after photodynamic therapy. J Fr Ophtalmologie 2004;27:1001-1006.
Marilita M Moschos, MD, PhD
Department of Ophthalmology, University of Athens, Athens, Greece
Correspondence and reprints:
Moschos M. Marilita MD, PhD
144, Kountouriotou Str
185 35 Piraeus
Greece
Tel : ++30 6944887319
Fax: ++30 210 4122139
E-mail: moschosmarilita@yahoo.fr
Dear editor,
We would like to give a response to the letter of Dr. Anshuman Sinha concerning our article "23 Gauge versus 20 Gauge System for Pars Plana Vitrectomy: A Prospective Randomized Clinical Trial".
For analysis of postoperative pain we used a simplified verbal rating scale (ranging from 0, meaning no pain, to 3, meaning severe pain). The standardized verbal rating scale reaches from 0 (no pain) to...
American pediatricians, armed with a new reimbursement code for photoscreening young children (99174), are very interested in the validity of potential instruments. As such, we were interested in the recent report that compared Plusoptix photoscreener to orthoptic exam in early primary school children, reporting 100% specificity but relatively low sensitivity: “the sensitivity of the PVS to detect amblyopia-associated f...
Dear editor,
We read with interest the paper by Wimpissinger et al comparing sutureless 23-gauge system to a standard 20-gauge system for pars plana vitrectomy, in a randomized clinical trial.[1] We aim to highlight a few issues in the design, methodology and analysis.
The authors have analysed postoperative pain and conjunctival injection as primary outcome measures. The effort by the assessor to elicit a...
I read with interest the recent study by Yi et al.
A very minor point... were the Stratus OCT images obtained using the "Radial Lines" protocol or the "Fast Macular Thickness" protocol? From Figure 1, I suspect that the higher resolution Radial Lines protocol was used (and not Fast Macular Thickness as described in the manuscript).
In any event, I commend the authors for a worthwhile addition to the li...
Dear Editor:
I read with interest the article by Dr. Cohn, et al regarding the natural history of autosomal dominant optic atrophy (DOA). The authors describe an average of 10-year follow up for 69 patients with genetically confirmed DOA. In their study, 6 (9%) patients enjoyed improvement in visual acuity by 2 or more lines.
I found this surprising, and I wonder if the authors could provide...
Author’s Response re letter by Nathan M Radcliffe
Dear Editor,
We are very interested to read Prof Radcliffe’s data showing a variable IOP rise in different subjects tested with the same goggle design. Their results, like ours,[1] suggest that individual anatomic or physiologic factors are important in determining the IOP rise. Currently, these factors are unknown with significant certainty, however som...
We would like to congratulate Drs Morgan and colleagues on their recent paper “Wearing swimming goggles can elevate intraocular pressure.” We performed a similar study and presented our data at the Association for Research in Vision and Ophthalmology in 2007. Our findings demonstrated that in healthy participants, IOP measurements taken during goggle wear were significantly higher at both one and five minutes, with an av...
Dear Editor
We thank Dr. Alm for his interest and comment on our paper entitled “Practical recommendations for measuring rates of visual field change in glaucoma.” We agree that the standard error of slope estimates is dependent on the number of examinations and duration of follow-up. However, these two parameters are not interchangeable. As pointed out correctly by Dr. Alm, the same number of examinations ov...
There are many pertinent and interesting observations in your article. As one of the first few users of PASCAL in India, we have now a large data-base of patients in a short span of time. Critical to understanding PASCAL is the fluence. Contrary to what we always thought, retinal hemorrhages and acoustic damage are not seen at 10 ms pulses if the fluence is within limits. I wish that PASCAL was also programmed to fix the flue...
Dear Editor,
In the article entitled 'Electrophysiological effects of intravitreal Avastin (bevacizumab) in the treatment of exudative age-related macular degeneration (ARMD)' by Karanjia et al (Br J Ophthalmol 2008), the authors examine the sensitivity of multifocal-electroretinogram (mfERG) at measuring changes in retinal electrical activity in response to Avastin treatment for ARMD. In this interesting paper t...
Pages