eLetters

608 e-Letters

  • Letter to Editor

    We have read with great interest the e-letter from Karakucuk et al. published in BJO responding to our paper titled ‘Acute retinal toxicity associated with a mixture of perfluorooctane and perfluorohexyloctane: Failure of another indirect cytotoxicity analysis ’ and we appreciate their positive appreciation of our research work.
    We consider extraordinarily important that they have reported four more cases in their country, thus, supporting that acute toxicity cases were not a Spanish problem as has been stated by some retinologist at an European congress (Barcelona, September 2017).
    We believe that this letter should encourage other colleagues from other countries from all over the world to report cases that certainly exist, according to non-official information from several companies.
    We completely agree that the ISO (the International Organization for Standardization) guidelines to determine the in vitro cytotoxicity of intraocular medical devices should be immediately changed. These guidelines should adopt direct cytotoxicity methods to be performed with finished, sterilized, and ready for release products. The analytical method utilized should include cells or tissues close to those of the retina to guarantee specific sensitivity and should be scientifically validated.
    We support the suggestion of increasing chemical research, because some companies are promoting chemical tests, as a “safety guarantee”, whose scientific validity and their direct...

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  • Pseudotumor cerebri in Behçet’s disease

    We read with interest the masterly review of the neuro-ophthalmology of Behcet’s disease by Alghamdi et al (1). One small aspect we question. The authors state that in their patients with papilledema: “The diagnosis of CVT was documented in all patients by cerebral angiography and MRI showing partial or total lack of filling of at least one dural sinus and an elevated CSF opening pressure (>25 mm Hg) on lumbar puncture.” We have recently reported 8 BD patients with pseudotumor cerebri who did not have cerebral venous thrombosis (CVT) on MRI or MRV (2). Partial or total lack of filling of one venous sinus does not constitute the pathophysiological basis for intracranial hypertension; either the sagittal sinus must be occluded, or if only one transverse sinus is occluded then the other needs to be stenosed (3). It would be interesting to know what a review of their patient’s images by a neuro-radiologist would reveal.

    1: Alghamdi A, Bodaghi B, Comarmond C, Desbois AC, Domont F, Wechsler B, Depaz R, Le Hoang P, Cacoub P, Touitou V, Saadoun D. Neuro-ophthalmological manifestations of Behçet's disease. Br J Ophthalmol. 2018 Apr 26. pii: bjophthalmol-2017-311334. doi: 10.1136/bjophthalmol-2017-311334.
    2: Akdal G, Yaman A, Men S, Çelebisoy N, Toydemir HE, Bajin MS, Akman-Demir G. Pseudotumor cerebri syndrome without cerebral venous sinus thrombosis in Behçet's disease. J Neurol Sci. 2017;383:99-100.
    3: Halmagyi GM, Ahmed RM, Johnston IH. The Pseudo...

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  • Letter to Editor

    Dear Editor:

    We read the article ‘Acute retinal toxicity associated with a mixture of perfluorooctane and perfluorohexyloctane: Failure of another indirect cytotoxicity analysis ’ by Coco et al. with great interest.[1] In this study, the authors reported on ocular toxicity due to perfluorooctane (PFO). They advised that the protocols used to determine the cytotoxicity of intraocular medical devices (which have been approved by the Organisation for the Standardisation of International Standards based on indirect methods) should be revised to ensure safety. We congratulate Coco et al.1 for their report because we believe that it has the potential to be a significant contribut or to the literature on this topic.

    As is commonly known, PFO is saturated with PFO liquids, which have highly stable carbon-fluorine bonds that consequently make them inert. PFO has highly specific gravity, low viscosity, optical clarity immiscibility in water and interface tension towards water. It is regularly used in vitreoretinal surgery for complex retinal detachment repair because it displaces subretinal fluid and blood anteriorly, unfolds the retina in giant retinal tear cases and provides counter traction and retinal stabilisation during membrane peeling in eyes with proliferative vitreoretinopathy.[2,3] These properties make PFO useful for intraocular surgery. However, some limitations exist regarding PFO use as a long- term tamponade such as amaurosis, a lack of light perce...

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  • Confounders to be addressed

    I read with great interest the article by Bae and collegues.1 In their retrospective study, the authors concluded that the presence of atypical epiretinal tissue (AET) in a full-thickness macular hole (FTMH) was related to poorer anatomical success and less visual recovery after surgery.
    I agree with the authors on the association of their OCT findings with the visual prognosis. I also agree with them that it is important to identify a good indicator of visual prognosis based on OCT findings. However, there are many confounders to be addressed in this study. For example, preoperative MH size with OCT has been known as a prognostic factor for postoperative visual outcome and anatomical success rate of MH surgery.2,3 A previous study also demonstrated that ERM prevalence increased with severity and size of the FTMH.4 In addition, preoperative visual acuity or preoperative photoreceptor integrity also seems to correlate with visual prognosis.
    Thus, their results should be supported by appropriate statistical analysis, that is, multivariate regression analyses. I hope that the authors will comment on the results of multivariate regression analyses to identify the most significant factor to predict visual prognosis after MH surgery.

    References
    1. Bae K, Lee SM, Kang SW, et al. Atypical epiretinal tissue in full-thickness macular holes: pathogenic and prognostic significance. Br J Ophthalmol. 2018 (in press)
    2. Ullrich S, Haritoglou C, Gass...

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  • Re: Optical coherence tomography angiography identifies peripapillary microvascular dilation and focal non-perfusion in giant cell arteritis

    Dear Editor,
    We read with interest the paper by Gaier et al.1 The collection of 5 eyes affected by acute A-AION and analyzed with OCT-A is remarkable, due to the rare disease presentation. The main finding of the paper was that during the acute phase of A-AION, diffusely dilated superficial peripapillary capillaries were detectable on OCT-A. Interestingly, peripapillary capillary dilatation was also noted in the fellow eye. Unfortunately, the figures presented by the authors are too small to allow the reader to qualitatively appreciate the capillaries dilatation. More detailed images and a quantitative vessels analysis would have helped to document the microvascular changes.
    They hypothesized that the capillary dilatation may represent a form of luxury perfusion in the setting of short ciliary arterial compromise or a centrally mediated autoregolatory mechanisms in the setting of reduced perfusion of the optic nerve. These hypotheses are interesting, but it is important to differentiate the RNFL thickness increase from the capillary dilatation, as peripapillary capillary plexus density and RNFL thickness are highly correlated and fit well with a nonlinear stacked-layer model.2
    Moreover, the authors stated that OCT-A laminar analysis did not highlight the choroidal/choriocapillaris perfusion defects seen on FA. However, a recent study3 showed a tight correspondence between the choroidal perfusion defects visible on FA (and even better on indocyanine green...

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  • Letter to the Editor - XFS

    Dear Sir,

    I was most interested to read the review by Nazarali and co-authors to mark the centenary of the description of the exfoliation syndrome, XFS(1) sometimes called the pseudo-exfoliation syndrome (2). It is always interesting to see how our understanding increases incrementally with time and reviews such as these are important in helping shape further investigations.

    The linkage of environmental factors and XFS is important and as they say not well understood. Nazarali and co-authors might like to reflect on the findings in Australian Aboriginal people (3). Aboriginal people were found to have very high rates of XFS, being present in 16% of those aged 60 and above. The presence of XFS was related to total global radiation exposure and occupation. Most interestingly, XFS was not associated with high intraocular pressure or glaucoma. Surely this is an area where more research is required.

    1. Nazarali S, Damji F, Damji KF. What have we learned about exfoliation syndrome since its discovery by John Lindberg 100 years ago? Br J Ophthalmol 2018; doi:10.1136/bjophthalmol-2017-3111321
    2.Dvorak-Theobald G. Pseudo-exfoliation of the lens capsule - relation to “true” exfoliation of the lens capsule as reported in the literature and role in the production of glaucoma capsulocuticulare. Am J Ophthalmol 2018; doi.org/10.1016/j.ajo2108.02.018
    3. Taylor HR. Pseudoexfoliation, an environmental disease? Trans Ophthalmol Socs UK 1979; 99: 302-307...

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  • We must continue testing delivery models to create more efficient surgical care

    We were interested to see Roberts, et. al study [1] which explored whether a hub-and-spoke model using a femtosecond laser (FL) could increase the efficiency and reduce the cost of cataract surgery.

    Although the model was not cost-effective when compared to conventional phacoemulsification surgery, more efficient models should continue to be assessed. The Aravind Eye Care system uses an alternative hub-and-spoke model. Instead of separate operating theatres (OTs), the physician alternates between two beds in a single OT. This model, and the safe reuse of surgical supplies, results in phacoemulsification cataract surgery with excellent outcomes at 1/20th the cost and carbon emissions [2-4].

    Roberts, et. al recommend that the ideal number of OTs to maximise the utility of an FL in a hub-and-spoke model is four. However, they were not able to evaluate the effect of adding additional OTs to their model as they only had two OTs. We suggest that adopting the Aravind model to jump to the 1:4 model without further building work could significantly alter this paper’s conclusions. We would be interested to know if elements of the Aravind model, two beds one theatre, could be adopted in their setting.

    On average patients receiving FLACS spent 5.85±1.99 mins in the laser suite (LS), implying a potential throughput of between 8 and 15 cases per hour. We are interested to know the authors views on the the limits of the FL and what impact the adoption of bilateral...

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  • AML and metastatic risk after ophthalmic artery chemosurgery for retinoblastoma

    We would like to add some data to this interesting discussion about the impact of ophthalmic artery chemosurgery or intra-arterial chemotherapy (OAC) in the occurrence of secondary malignancies in children with retinoblastoma with germline mutations of the Rb1 gene.
    The discussion about the incidence of secondary leukemia is an important one. Secondary leukemias usually present early in the patient follow-up, usually around 2-3 years. Systemic chemotherapy has been implicated in their occurrence since, they were not identified as a common secondary malignancy in patients with retinoblastoma not receiving chemotherapy1. Their occurrence is low1, but as the case Dr Meadows and Lahey report are usually refractory to treatment and usually fatal. In our series of patients treated with systemic chemoreduction for conservative therapy from Argentina, secondary AML was the most common fatal secondary malignancy with a total of 2 out of 129 cases. We had a third case in a child receiving chemotherapy for extraocular disease, similarly to Dr Meadows and Lahey’s case2. In our current, yet unpublished results with ophthalmic artery chemosurgery, we had no case of secondary AML , in 71 consecutive cases with bilateral retinoblastoma treated with OAC with a median follow-up of 42 months. Secondary AML has been widely reported as a complication of systemic chemotherapy in pediatric oncology patients 3 including those receiving epipodophillotoxins 4and also alkylating agents5. Cum...

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  • Intravitreal methotrexate for vitreoretinal lymphoma has a very low local recurrence rate

    Dear Editor,
    We have read with interest the paper by Klimova et al. Some statements in the paper are confusing and may even mislead the readers.

    The authors claim in the survival section of the paper that: "Vitreoretinal lymphoma is a life-threatening disease, with a 5-year survival rate of 71% in our study". Vitreoretinal lymphoma (VRL) may affect vision, and in very advanced cases that we rarely see in recent years, may destroy the eye. However, VRL per se is not what that kills the patients, but the associated brain lymphoma or in some case the systemic lymphoma.

    According to the results in this study (and the title of the paper), "Combined (local and systemic) treatment in patients with PVRL showed favorable results in comparison with local therapy alone (p=0.695). However, the statistical significance was not reached". It is no wonder that they claim that combined treatment is better than local treatment when they have 60% relapses. However, no other study of intra-vitreal (IVit) Methotrexate showed such a high relapse rate. In our experience, the relapse rate is extremely low with IVit methotrexate alone. Actually, in summarizing our ten years results we had no recurrence of the intraocular disease (2) and summarizing now our 20-year experience with 113 eyes, we had only two cases of recurrences (unpublished data). It is difficult to explain the poor results of the authors’ patients, using either intravitreal methotrexate al...

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  • Outcomes of penetrating keratoplasty in congenital hereditary endothelial dystrophy

    Dear Editor,
    We have read with interest the recently published article by Al Arrayedh H, Collum L, Murphy CC (1). The authors concluded that a poor outcome was seen after PKP for CHED in Irish population, which arises from a combination of dense amblyopia and a high risk of graft failure in the long term. This is an important study which has a unique cohort of only autosomal recessive cases from a large Irish consanguineous family.
    We want to highlight some points in this article that were not clearly described .
    Author reported 2 previously diagnosed congenital glaucoma cases, which also affects the visual outcome of the surgery and may skew results of this study. But they had not mentioned clearly about this.
    In the figure 2 , the failed DSEK case also received regrafting twice but that was not shown in the legend.Also 32 eyes received penetrating keratoplasty as per the text but in that figure , 33 was mentioned.
    In some previous studies 12 years of age (2,3) has been mentioned as the demarcation for outcome of penetrating keratoplasty in congenital hereditary endothelial dystrophy . This was not analysed in this very important study (maybe because of small numbers) but it could have been a useful clinical hint for timing of surgery in these patients.

    Thanks

    1. AlArrayedh H, Collum L, Murphy CC. Outcomes of penetrating keratoplasty in congenital hereditary endothelial dystrophy. Br J Ophthalmol. 2018 Jan;102(1):19-25
    ...

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