134 e-Letters

published between 2014 and 2017

  • Big data, selection bias and clinical significance

    Title Page

    Letter to the Editor

    The article in question:
    Crewe JM, Threlfall T, Clark A, Sanfilippo PG, Mackey DA. Pterygia are indicators of an increased risk of developing cutaneous melanomas. Br J Ophthalmol 2017.

    Jingjing Shen
    Minqian Shen
    Yuanzhi Yuan

    Corresponding author:
    Yuanzhi Yuan

    Address:#180 Fenglin Rd., Department of Ophthalmology, Zhongshan Hospital Affiliated to Fudan University, Shanghai 200032, P.R. China
    Email: yuan.yuanzhi@zs.hospital.sh.cn
    Phone: +86-186 1688 1220 or +86-21-64041990 ext. 2684

    Dear Editor,

    We read with great interest the paper by Crewe et al.1 The authors showed that patients with pterygium had higher risk of cutaneous melanomas (CM) in a large retrospective matched-cohort study in Western Australia (WA), and suggested pterygium as an indicator for CM. The finding was interesting. However, we doubt the conclusion and its clinical relevance and public health significance.

    Compared to control group, patients with pterygium had a 20% or 24% increased risk of developing CM in terms of odds ratio(OR) or incidence rate ratio (IRR), respectively. The incidence rate difference(IRD), however, was only 27.7/100 000 person-years (PY) (Table 5., by subtracting the IR of the control group from that of the pterygium group, i.e. (186.5-158.8)/100 000 PY). The rate difference corres...

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  • Reply

    We read with interest the insightful comments in the e-letter submitted by Dr. Gain, Dr. He, Dr. Garcin, and Dr. Thuret on our recently published article.1 As stated in their letter, they previously reported that by using a similar triple staining (i.e., Hoechst 33342, ethidium homodimere and calcein-AM) on the endothelium of whole donor corneas stored in long-term organ culture, the endothelial cell (EC) density in the whole pool of viable ECs in the cornea is routinely, and quite substantially, overestimated.2,3 We completely agree with the authors regarding the importance of assessing the whole pool of viable ECs in corneal grafts.

    We first reported at the 2009 Annual Meeting of the Association for Research in Vision and Ophthalmology (ARVO) that triple-staining a donor graft with propidium iodide, calcein-AM, and Hoechst 33342 allowed for a distinct discrimination between living cells and dead cells. In that report, we hypothesized that the existence of dead cells on the endothelium of the donor cornea suggests an association with the rapid loss of corneal ECs, at least at the early phase, post keratoplasty. However, Gauthier and associates reported3 that there was no difference between the density of viable ECs at day 0 and at day 5 postoperative, thus suggesting that very early EC loss in the host recipient is almost negligible. However, similar to Gain and associates, we believed that it was quite important to measure viable ECD, not to calculate just ECD by...

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  • eletter

    We noticed the article entitled “The existence of dead cells in donor corneal endothelium preserved with storage media” by Kitazawa with interest (Br J Ophthalmol 2017. Oct 5).
    Authors clearly demonstrated, using a triple staining with Hoechst, Propidium Iodide and Calcein-AM, that corneas stored at 4°C in Optisol-GS for 3 to 7 days, the technic most used worldwide, bear a significant number of dead endothelial cells (ECs). They underlined that these non-viable ECs are not recognized by specular cell count done by the eye bank and that this could explain the “cell loss” inevitably noticed post graft. Our team applied, for the first time in 2011 [1] and again in 2016 [2], a similar triple staining on the endothelium of whole corneas stored in long-term organ culture at 31°C, the dominant technic in Europe. We made the same findings as Kitazawa et al. and defined the notion of viable ECD (vECD) as the number of viable ECs per surface unit. Areas without ECs (especially in Descemetic folds), dead and dying EC (that will not survive the storage) clearly explain the important discrepancy between the cell count done by the eye bank (unable to spot them) and the very early postoperative ECD. Our team also demonstrated long ago that vital Trypan blue staining used by certain eye bank is unable to spot all dying cells because its time window of positivity is very narrow, corresponding only to ECs near to desquamate [3]. Viable ECD determined by triple staining therefore appea...

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  • Re: e Letter for bjophthalmol-2017-310312; Comments on article “Impact of Surgical Timing of Postoperative Ocular Motility in Orbital Blowout Fractures”

    Dr. Jost Jonas

    British Journal of Ophthalmology


    Dear Dr. Jonas:


    With great interest, we read the e letter (E-Letter 1) submitted by Ankita Anil Patil, Srikanth Ramsubramanian, and Bipasha Mukherjee, entitled “Comments on article ‘Impact of surgical timing on postoperative ocular motility in orbital blowout fractures’” illustrating their analysis and opinions on our article that was recently published in the British Journal of Ophthalmology. Please know that we greatly appreciate the authors’ cogent and helpful comments.


    It should be noted that in our opinion, in order to normalize ocular motility, the most important aspect is to restore the orbital tissues for the appropriate location. It is quite well known that the transcaruncular approach is suitable for small fractures of the medial wall. Since the transcaruncular approach provides surgeons with only a narrow view, it is difficult to restore the orbital tissues for the appropriate location for a large depressed fracture. On the other hand, the Lynch incision provides a substantial advantage for the repair of an orbital fracture, as it allows for a wide view during surgery and makes it easy to restore the orbital tissues for the orbit and insert the reconstruction implant. In additi...

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  • Building a reliable evidence base in eyes and vision

    Dear Editors,

    We are writing to express concerns about an article published recently in BJO. (1) While Joksimovic and colleagues claim to have conducted a systematic review, they did not. Rather, they describe a cross-sectional study of randomized trials in ophthalmology with two comparison (or “exposure”) groups: trials published in ophthalmology journals, and trials published in general medical journals. In contrast, a systematic review (also a cross sectional study) has been defined as "… a scientific investigation that focuses on a specific question and uses explicit, prespecified scientific methods to identify, select, assess, and summarize the findings of similar but separate studies." (2)

    To minimize mislabeling of systematic reviews, among other purposes, Cochrane Eyes and Vision (CEV) is partnering with individual ophthalmology and optometry journals to appoint a knowledgeable associate editor responsible for editorial functions related to systematic reviews at each journal (http://eyes.cochrane.org/associate-editors-eyes-and-vision-journals). Our research has indicated that many published eye and vision articles billed as “systematic reviews” do not adhere to accepted criteria, and are not reliable. (3)

    In addition to adding associate editors for systematic reviews to their team, journal editors can insist that authors adhere to reporting standards, f...

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  • Reply to Aptel et al.: Management of postoperative inflammation after cataract and complex ocular surgeries: a systematic review and Delphi survey

    Aptel et al. [1] presented the prevention and management of postoperative ocular inflammation after cataract surgery based on randomised controlled trials, while after trabeculectomy, vitrectomy and combined phacovitrectomy in a two-round Delphi survey.

    The Delphi survey is a technique applied mainly to develop healthcare quality indicators. [2] In this study not only was it applied to evaluate practice patterns among ophthalmologists, but to obtain information on inflammatory potential of a surgical procedure that can be assessed by objective methods.

    It should be underlined that even within the formerly mentioned indications there is little recommendation among researchers to use the Delphi method. [2] The use and reporting of the method needs to be improved, while a panel composition of experts in one field significantly influences ratings. [2,3] Several issues regarding the selection of the panel members is critical if the group consensus technique is to work properly. Two hundred and twenty surgeons from Europe (35%) and the USA (59%) were invited to participate in this Delphi survey. The response rate among the invited experts should be thoroughly explained, as finally 82% of the participating experts were from Europe and the balance was from the USA. This discrepancy might have a high risk of bias and should be thoroughly discussed. Of record, in the United States retinal surgeons do not routinely perform cataract surgery, thus including them in the e...

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  • Comments on article "Impact of surgical timing on postoperative ocular motility in orbital blowout fractures

    We have read the article”Impact of surgical timing of postoperative ocular motility in orbital blowout fractures” by Yukito Yamanaka, Akihide Watanabe, Chie Sotozono, Shigeru Kinoshita published in BJO on July 25 2017.The article discusses a new technique of Hess Area Ratio (HAR) and CT-scan findings for determining the appropriate time for surgery and predict the outcomes following orbital fracture repair.
    We want to congratulate the authors for this successful review article. We would like to comment on some points in the methodology and results of this article and make some contributions.The incisions described in the article have some shortcomings and are not currently the favoured approach. The Lynch incision described in the article has been the traditional approach for medial wall fractures but can result in severe scarring or webbing of the medial canthal skin ; therefore the transcaruncular approach is favoured.1 The subciliary incision too can cause ectropion and a transconjunctival approach is preferred.2 The number of patients mentioned in the results section who had poor improvement of HAR% differs being recorded as 22 earlier and then later in the article as 24.The diagnosis of tissue incarceration causing ocular motility disturbances after surgery is more related to various ocular motility tests rather than CT-SCAN findings alone.3 The authors have diagnosed muscle and tissue incarceration based solely on CT-SCAN findings and have not commented on t...

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  • Comment on “The role of specific visual subfields in collisions with oncoming cars during simulated driving in patients with advanced glaucoma”

    Kenzo J. Koike, MD1; Lauren S. Blieden, MD1,2; Yvonne I. Chu, MD1; Silvia Orengo-Nania, MD1,2; Kristin S. Biggerstaff, MD2; Bac T. Nguyen, MD1; Peter T. Chang, MD1,2; Benjamin J. Frankfort, MD, PhD1

    Assessing the visual standards to safely operate a motor vehicle is a challenging topic and discussion that we regularly encounter in our glaucoma population. Multi-centered and population-based studies previously have shown that patients with glaucoma are at particularly increased driving risk, due to their visual deficits.1,2 As such, we greatly appreciate the contributions from Kunimatsu-Sanuki and colleagues, who evaluated patients with advanced glaucoma, and how they performed with a driving simulator. As part of their analysis, the authors focused on specific visual sub-fields, and how those may correlate with the incidence of motor vehicle collisions (MVCs). Their conclusions noted that inferior visual field deficits, age, and visual acuity, were significant factors that contributed to the rate of MVCs. However, we noticed that visual acuity of the better eye (recorded as logMAR) was a significantly higher risk factor (odds ratio of 28.59 and 75.71 for analyses 1 and 2, respectively, as shown in Table 3) for collisions during simulated driving. With such a dramatically higher risk of simulated collision based on visual acuity, it is likely that this parameter alone is the most significant factor to influence the risk of MVCs. As there is some discrepancy in the li...

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  • Optic nerve head swelling on ultrasound and optical coherence tomography in children

    Dear Editor,
    we read with great interest the article by Dahlmann-Noor et al. concerning the possibility to detect optic nerve (ON) head swelling on ultrasound and OCT. 1
    They reported 61 children , investigated for ‘suspicious discs’ that underwent both US and OCT. Among these only 3 children had intracranial hypertension (IHT) but all of them were diagnosed as having drusen on US; even the three children with IHT had ‘small linear’ drusen.
    We would like to comment on small linear drusen that seem to have been undetected by OCT. This is very unlikely. Much care must be taken to diagnose linear drusen with ultrasound because this image could be an artifact due to the strong echoes coming from a surface where the sound beam is perpendicular .
    Measuring optic nerve sheath diameter (ONSD) with B-scan has recently become popular, but there is not a global agreement on how to perform such a measurement as some authors suggest performing axial measurements, some others coronal axis measurements.3-5 Furthermore to establish a cutoff between normal and increased ONSD can be very challenging due to the so-called blooming effect. This B-scan related effect, that should not be confused with the Doppler related one, is due to the lack of sensitivity standard setting: the ON image obtained with a low sensitivity setting will result in larger ON dimensions compared to the ones provided by the same image, increasing the sensitivity setting.
    The authors...

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  • Comment: “The patient is speaking”: discovering the patient voice in ophthalmology

    We have read with interest the article by Dean et al(1). We completely agree with the premise that the ‘patient voice’ is not being fully utilised in all facets of ophthalmic care, ranging from research to clinical practice. Evidence suggests that rather than being a tokenistic addition, listening to the ‘patient voice’ can provide tangible improvements in cost efficiency and healthcare outcomes(2).

    A successful project spearheaded by the European Respiratory Society (ERS) called EMBARC(3) (European Multicentre Bronchiectasis Audit and Research Collaboration) sought to be a patient focused project, despite scarce existing infrastructure for patient involvement(3). In the research sphere of the project, patients were involved in clinical trials and studies. They played key roles in study design, wrote letters to secure financial backing for bronchiectasis-related projects, and were active members of advisory boards and ethical committees. Patients were a valuable asset on guideline panels, providing an alternative insight on the merits and negatives of various interventions, as well as their general acceptability. This initiative is a model example of how patients can influence the path research takes, and provides a tested framework for future ophthalmic research to be highly patient-relevant.

    Undoubtedly, there will be barriers to effective patient involvement in medical research and these will require flexible and innovative approaches to be overcome. These...

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