592 e-Letters

  • 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.


    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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  • Response to AML after OAC

    Dear Sir,

    We are writing this letter in response to a “letter to the editor” from Drs. Leahey and Meadows about our recently published paper “Second primary malignancies in retinoblastoma patients treated with intra-arterial chemotherapy: the first 10 years”.1 There are a number of incorrect statements in their letter and we hope this letter will clarify those errors made by them.

    1) Drs. Leahey and Meadows state that…”the author’s report is profoundly misleading with regard to the risk of SPMs following OAC”. To prove that they then state that the median follow-up range is 2.5 years with a maximum follow-up of 12 years. How is that “profoundly misleading”? In the same paragraph they then state that patients failing OAC required radiation therapy and suggest that all of these second neoplasms are a consequence of radiation. That is not true. In our paper (page 273, Table 3) we documented that not one of the children who developed a second tumor had received radiation. How could radiation be the cause of a second tumor if the patients never received radiation? Dr. Leahey and Meadows also wrote that…”patients failing OAC require radiation”. That’s not true. On page 272 we stated that…”patients who received external beam radiation prior to presentation at our clinic were excluded from analysis”. None of the patients in this series received radiation after OAC and no patient in our center has received radiation in the past 10 years. We do not dispute that radia...

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  • Planning an extra-ocular muscle biopsy: a note of caution.

    We read the excellent paper ‘Review of extraocular muscle biopsies and utility of biopsy in extraocular muscle enlargement’ by Eade et al.1 with great interest. The authors reviewed the pathology in extraocular muscle biopsies performed over a 25-year period and reported the clinical and radiological features that might distinguish between benign and malignant diseases. As the authors note, it is imperative for the orbital surgeon to consider a muscle biopsy when the diagnosis is in doubt. With this in mind we would like to highlight two relevant cases of simulated extraocular muscle enlargement seen radiologically due to deviated ocular position rather than a pathological process related to the muscle itself. In both cases this confused the clinical picture and nearly resulted in needless surgery.

    In case 1, a 42-year-old woman was referred to the oculoplastic clinic with diplopia, reduced vision in the right eye associated with retro-bulbar pain and facial paraesthesia. On examination, there was evidence of a right esotropia with a reduction of abduction (consistent with a 6th cranial nerve palsy) associated with reduced sensation involving the V1 and V2 distribution. Optic nerve function was normal. Investigations revealed an elevated serum IgG subclass 4 (1.18 g/L) and normal serum ACE. The MRI report confirmed increased girth of the right medial rectus muscle in conjunction with enlargement and pathological enhancement of right cavernous sinus extending into...

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  • Acute Myeloid Leukemia following OAC

    Having read the article of secondary primary malignancies (SPM) in patients treated with ophthalmic artery chemosurgery (OAC) (1), we wish to update Dr. Habib’s report. A patient with unilateral Group D heritable retinoblastoma (RB) treated by their team with 5 OAC treatments in 2012 through 2013 developed acute myeloid leukemia (AML) on 4/26/2017 and died 3 months later.
    Following an intraocular recurrence after OAC and subsequent enucleation the patient’s care was transferred to our institution. Despite adjuvant chemotherapy he developed widespread bone and marrow metastases 8 months after enucleation. He then underwent intensive chemotherapy and an autologous stem cell transplant. Twenty eight months later he developed AML with a fms-like tyrosine kinase 3 (FLT3) mutation. Melphalan administered during all OAC treatments and the drugs administered following that failure must be implicated in this outcome (2). By failing to eradicate retinoblastoma, metastatic disease ensued requiring further treatment and subsequently, AML.
    The author’s report is profoundly misleading with regard to the risk of SPMs following OAC. Although the maximum period of follow-up is 12 years, the median is 2.5 years. Patients failing OAC required radiation therapy and are known to be 3 times more likely to develop additional cancers (3). We await that follow-up.
    The goal of RB care is cure. This patient’s course illustrates the danger of failing to prevent metastatic disease wi...

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  • Combination therapy for Fungal keratitis: Should we go for it?

    We read with interest the report by Sradhanjali et al(1) demonstrating more effective antifungal activity of combination of Natamycin and voriconazole than single-use in vitro treatment. It should be noted, however, that given the small sample size, these results should be confirmed with a larger dataset.

    Caution should be exercised when inferring results from in vitro studies because it always do not translate to in vivo models and are inconsistent. In our hands, we found treatment success when adding topical voriconazole 1% with natamycin 5% in recalcitrant full thickness infiltrate cases of fungal keratitis. This may be because topical natamycin acts superficially whereas voriconazole, though not as effective as Natamycin, takes care of the deeper infiltration because it has better penetration than Natamycin. Sharma et al (2) also concluded that topical voriconazole seems to be a useful adjunct to natamycin in fungal keratitis not responding to topical natamycin. Debridement of ulcer also helps in these cases giving way for the drug to act and reducing the fungal load.

    Given the poor susceptibility and clinical outcomes among Fusarium ulcers treated with voriconazole, Sun et al(3) recommended against using voriconazole as a first-line therapy for Fusarium keratitis. Li et al(4) recommends against combination therapy because of possible interactions in mechanism of drugs. We believe that combination therapy as a first line of treatment may compound the pr...

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  • Reply to 'Big data, selection bias and clinical significance

    We thank the authors for their comments and insights on our paper ‘Pterygia are indicators of an increased risk of developing cutaneous melanomas’.
    We agree that there was selection bias within the pterygium cases. All cases were identified as hospital in-patients and therefore represent that small select portion of the population who were receiving treatment for (or removal of) their pterygium. We made no assumptions about whether these cases were more or less severe than untreated pterygia or whether the removals were performed for cosmetic or other reasons. The strengths of this study are that it included all in-hospital cases treated in Western Australia over a 30 year time period, without prejudice.
    While melanoma is an uncommon problem in China, it is a major health issue in Australia and New Zealand. The clinical relevance of this study should be viewed against the background of the world’s highest incidence rates of cutaneous melanoma that currently exist, with up to 60 cases per 100,000 population1-3 in Australia and New Zealand. Contrast this with the incidence rates of East Asian countries of approximately 0.7 cases per 100,000 population.4 Both non-melanoma and melanoma skin cancers are a major health priority for cancer prevention research. We are not suggesting that pterygium be used as the sole indicator for a population wide screening program. There are well established major screening and surveillance programs in place in Australia. Our study a...

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  • Spurious elevations in serum IgG2 may be seen by immunonephelometry in IgG4-RD - response to Chan et al [1]

    Chan et al report on marked elevations in serum IgG2 that are observed in patients with orbital IgG4 related disease (IgG4-RD), with or without systemic involvement.

    Using ROC area under the curve comparisons, the authors show that the serum IgG2 concentration has a higher AUC (0.9) than serum IgG4 (0.8) in detecting IgG4-RD in their cohort (comprised of 33 subjects: 20 with orbital IgG4-RD with or without systemic involvement, and 13 with non-IgG4-RD orbital inflammation).

    Our group has noted this paper by Chan et al with interest as we have observed the same phenomenon of marked serum IgG2 elevations in patients with IgG4-RD, who have concomitantly low serum IgG4 concentrations. Like the patients presented by Chan et al, our IgG4-RD patients uniformly had serum IgG2 concentrations that were greater than the serum IgG4 concentration, even when the serum IgG4 concentration was very high.

    Our interpretation of the apparent superior clinical utility of the serum IgG2 test in this context, is that this observation is only made when using an immunonephelometric methodology subject to two different types of analytical error:
    i) antigen excess, leading to falsely low serum IgG4 measurement in a patient who in fact has a marked elevation of serum IgG4 [2] and
    ii) cross reactivity of the reagent used to measure IgG2 with serum IgG4, leading to falsely high serum IgG2 measurement (this may be due to a direct and specific recognition of IgG4 epitop...

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