Reviewer's report
 Development of a clockwork light source to enable cervical inspection by village health workers Title:
Authors:
Fidelma O'Mahony Dr (fidelma@meole2.freeserve.co.uk )
Bob Bailey Mr (rds@rshmes.demon.co.uk )
Chris Koller Dr (Chris.Koller@nstaffs.wmids.nhs.uk )
Collette Sheridan Ms (cms@mcmedia.com.au )
Richard Steventon Dr (rds@rshmes.demon.co.uk )
Kalyan K Dhar Mr (KDhar@compuserve.com )
Richard B Johanson Prof (richard@kogs.freeserve.co.uk )
 2  20 Jun 2002 Version: Date:
Reviewer:
 not specified Level of interest:
 Accept after discretionary revisions Advice on publication:
This paper purports to describe the successful development of a cheap, portable, light source for use 
with exams involving visual inspection of the cervix after acetic acid wash (VIA), or any other 
gynecologic indication for that matter. 
The authors are basically reporting on a bench-research project, in which they indicate that they have 
established the working parameters of their light source. This work is innovative and could have 
programmatic potential in the field, however what is clearly missing from this report is whether the light 
has clinical functionality in practiceaE"independent of where it might be used. To this end the authors really need to test the light in a clinical situation to see whether, independent of any technical findings, 
that light is actually clinically usefulaE"that it does what the authors want it to do. Such an assessment 
doesnaETMt have to be a full scale project to establish the sensitivity and specificity of VIA in a 
low-resource setting using this light source, but merely a clinical exercise in which a clinician sits down (or stands up if they prefer) and assesses whether the light is practical to use (see some of the 
comments below) and whether, in practice, it provided adequate illumination of the cervix. 
The additional comments below should be addressed prior to accepting for publication and should help 
strengthen the content and methodology. 
1. Background, Para 2, last sentence. I think the authors probably mean that in low-resource settings 
aEaEportable power supplies and batteries are a desirable commodity and are rapidly diverted to other settings and applications.aE 
2. Background, Last Para line 5. Why did the authoraETMs want this to be waterproof? Even in the most
primitive settings GYN exam are usually conducted indoors and while these is certainly the occasional 
copious discharge, I donaETMt know that an instrument would have to be actually waterproof to be 
useful. 
3. Materials and Methods, Para 3. The authors indicate that aEoeaE60 turns on the handle will provide 
sufficient charge to operate the light for around 3 minutes.aE For the nurse who would have to aEoechargeaE the light in this way, how much effort is involved? Will staff get carpal tunnel syndrome 
or some similar affliction of the wrist if they are continually charging the light in order to screen, say 
25-30 women/day, with each exam requiring 6-20 minutes (depending on whether cryotherapy or some other treatment is offered/performed on the basis of the VIA test immediately following the test) of light 
per patient? This is one of the reasons why a practical assessment of the device independent of setting 
is important. 
4. Materials and Methods, Para 3. If one could charge the light electrically, how many minutes/hours of 
light does one get per charge. This might be an effective way to use the light, too. The fact that it can be
aEoewoundaE to charge it could serve as a back up when the battery gives out. The authors should provide some indication of how the light performs on the battery. 
5. Results, Para 3, Line 3. The authors indicate that torches are commonly used in the UK for cervical 
inspection in the UK. I didnaETMt know that aEoecervical inspectionaE, presumably with a view to 
rule-in or rule-out disease was commonly performed in the UK. If so, and if they are using torches, it 
would be best to reference this as I think this might be news to many of my colleagues. If aEoecervical 
inspectionaE here just means localizing (finding) the cervix for purposed to taking a Pap smear, then 
that is different, but I am surprised to know that people in the UK are using torches for this. Is there a 
standard torch approved or recommended for this purpose? Or is that one of the problems? 
6. Discussion, Para 2, Line 8. The citation mentioned in connection with reference 3 is incorrect. The 
correct citation would be (and I have re-phrased a bit) aEoeIn their report from Zimbabwe, The 
University of Zimbabwe/JHPIEGO Cervical Cancer Project suggested thataE.aE To be sure, this is a 
aEoecorporateaE author and no one person is the first, senior, or designated author. Thus the 
assignation of aEoeChirenje et alaE improper. 
7. Discussion, Para 3. The authors again allude to the use of torches in the UK for cervical inspection. 
My own review of the literature does not turn up any mention of cervical inspection as a means of primary screening or triage as part of a cervical cancer screening programme, so again a reference 
would be useful. If, as mentioned before, the use of the torch is more of the aEoeany port in a stormaE 
approach and the idea is just to see whether a cervix is present for smear taking or determining 
evidence of gross disease such as a polyp, then it would be better state aEoefor gynaecological examsaE instead of for cervical inspection. 
Also, in their bench study, did the authors compare their results to Halogen-bulb containing torches? In 
our experience, these provide a very satisfactory intense aEoewhiteaE light and in some of the torches 
the beam can be focused to a wide or narrow aEoelight throwaE depending on the cervix and depth of 
the vagina. Can the beam in the clockwork device be focused? 
8. References. Reference 3 appears to contain 2 references. The WHO Bulletin report should be listed 
separately, no? 
9. Figure 1. This figure should label the respective components of the experimental set-up. That 
electrical unit does not look very aEoelow-techaE and I think the reader should know that this is the unit 
that measures the light intensity and is not actually part of the system. The speculum simulation system
should also be labeled as such. Lastly, regarding the black wire that extends from what appears to be 
the back of the unit, has a white switch on it and runs to the aEoespeculumaE, is that the actual light 
source. In Figure 4 (not numbered) it shows the very nice thin (presumably flexible) light attached to the 
speculum, but doesnaETMt show how it relates to the device. That would be useful. So if the black wire 
contains the light source used for the gynae exam, then is the other big light that appears on the 
aEoefrontaE of the unit just a regular torch? So you could use this for gynae exams or if you have to 
change a tyre on the motorway in the dark? 
10. Candles. In the Background section, the authors indicate that candles may offer the only source of 
illumination in some settings. Do they mean for gynae exams? I have been in literally dozens of developing countries, almost every Anglophone (and some francophone) countries in Africa and have 
never seen a candle used for vaginal/cervical illumination. I suspect that if candles are the only source 
of light in the facility, that gynae exams involving a visual component are simply not done, and if, in such
a setting someone attempts to take a Pap smear, it helps explain why they are so bad, but if candles 
are being used to illuminate the vagina, I would like to know more. 
11. VIA test parameters. In the Discussion, the authors indicate that aEoecompared to cytology, VIA is 
less specific with low positive predictive value (PPV) for high grade disease.aE To state that the PPV for
VIA is aEoelowaE is somewhat judgmental since the values reported to date are highly dependent (as 
would be expected) on the prevalence of disease in the population and the capabilities of both those 
performing cytological analysis and those performing VIA. Do the authors have cut-off points for what 
they consider to be low vs. medium vs. high? It is worth remembering that increased specificity 
(commonly with a dividend of an increased PPV) usually comes at the expense of sensitivity. Thus the 
PPV may be higher, but most of the cases of disease are missed. The main issue relates to 
management and cost. If the PPV is uncomfortably low and the only treatment/management is morbid, then the test may not be worthwhile, but if the treatment/management is benign/safe/cheap, then the 
PPV may not be critical. In the results alluded to in reference 6 it is sensitivity that drove the equation, 
not the PPV. I would remove the mention of low PPV since it is not really germane to the discussion, but
agree that a good light source may improve specificity with, perhaps minimal expense to sensitivity. 
12. Cost effectiveness. The information contained in reference 6 was published in JAMA in 2001. ( 
JAMA 2001 Jun 27;285(24):3107-15) I think it would be better to use this citation. 
Competing interests:
None declared.