eLetters

641 e-Letters

  • Collaterals or telangiectasias?

    I read with great interest the paper titled “Collateral vessels on optical coherence tomography (OCT) angiography in eyes with branch retinal vein occlusion (BRVO)” by Suzuki et al.1
    The authors defined collateral vessels as dilated and tortuous capillaries occurring in pre-existing capillary beds and linking the obstructed vessel with the nearest patent vessel, according to previous reports.2-4 The authors demonstrated that collaterals were detected in 23 out of 28 (82%) eyes, all of which already existed at mean 0.95 months after the onset, and that all of the collaterals were observed in both the retinal superficial and the deep layers.
    However, some of the vessels which are pointed out as collaterals in the study1 look like simply dilated/tortuous vessels, because they don’t seem to connect obstructed to non-obstructed adjacent vessels nor by-pass obstructions. In a previous report, the authors found collateral vessels in 18 out of 28 (64%) eyes at mean 25.1 months from the onset, while superficial and deep capillary telangiectasias were detected in 13 and 28 out of 28 eyes, respectively.4 Therefore, I suppose that some of the vessels defined as collaterals in this study1 may be simply telangiectasias.
    Fruend et al.5 defined collateral vessels as the authors did. After excluding collaterals involving the perifoveal vascular ring, they demonstrated that collaterals were found in 23 out of 23 eyes (100%) at median time of 3.79 years from RVO...

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  • Intraocular pressure change after injection of intravitreal dexamethasone (Ozurdex) implant

    I read with interest and appreciate the article by Choi et al 1 on 'Intraocular pressure change after injection of intravitreal dexamethasone (Ozurdex) implant in Korean patients'.
    As the study looks at the IOP changes after intravitreal dexamethasone implant, how the IOP was recorded for the patients is very important. The authors have reported that the intraocular pressure (IOP) was measured by non-contact tonometer (NCT) or Goldmann applanation tonometry (GAT) in this study. First, it is not mentioned as to which NCT was used for IOP measurement. If NCT was used to measure pre-injection IOP, was it used to measure post-injection IOP measurement also? Or on different visits IOP recording was done with NCT or GAT, is not clear. As GAT is still considered as a gold standard for IOP measurement, if IOP on NCT is found to be high, ideally it should be rechecked with GAT. Second, it is not mentioned whether a single IOP measurement was taken or multiple IOP measurements were obtained, taking the average value as the final IOP. Third, a s the lower range of age was 16 years (Table 1), was there any correlation of IOP change after the injection with the age?

    Reference

    1. Choi W, Park SE, Kang HG et al. Intraocular pressure change after injection of intravitreal dexamethasone (Ozurdex) implant in Korean patients. Br J Ophthalmol 2018. Epub ahead
    of print. doi:10.1136/ bjophthalmol-2018-312958

  • Reply to: Comments on "Accuracy of trained rural ophthalmologists versus non-medical image graders in the diagnosis of diabetic retinopathy in rural China"

    Dear Editor,

    We thank Drs Sabherwal and Sood for their interest in our article.(1) We would like to respond to the interesting points they raise.

    Table 3 presents our analyses of potential predictors of the correct diagnosis by rural doctors of diabetic retinopathy (DR) requiring treatment. Details on a number of the characteristics assessed in this table are presented in the first paragraph of the Results section, but not, as Drs Sabherwal and Sood point out, the proportion having received didactic training. Among the 28 rural doctors, 13 (46.4%) received such training and 15 (53.6%) did not.

    In the Methods, we describe in detail the training received by ophthalmologists in the CREST (Comprehensive Rural Eye Service and Training) program. As described there, only two doctors per hospital (not all of whom examined patients in the current study) could attend the didactic phase of training at the Zhongshan Ophthalmic Center (ZOC). This is due to the limited number of ophthalmologists at a typical rural Chinese county hospital, and the heavy load of clinical duties. For more doctors to have left their facilities for the two-month didactic training would not have been practical. However, all ophthalmologists participating in the CREST network and in the current study received intensive hands-on training by medical retina experts from ZOC at their own facilities, which included the diagnosis and laser treatment of diabetic retinopathy (DR) as well as the u...

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  • Addendum

    Dear Editor,

    It has come to our attention that three of the patients (# 2 and #3, half-brothers, and #10) from our paper in BJO (1) have been reported previously with video recordings but without eye movement recordings at age 0 to 3 years in symposium proceedings (1) prior to the eye movement recordings made at age 6-11 presented in this study.

    Yours sincerely

    Irene Gottlob

    References

    1) Pieh C, Simonsz-Toth B, Gottlob I. Nystagmus characteristics in congenital stationary night blindness (CSNB). Br J Ophthalmol 2008;92:236-240.

    2) Simonsz HJ, Gottlob I, Kommerell G, Hergersberg M, Eriksson AW: Transient Infantile Upgaze Holding Insufficiency: Frühsymptom bei inkompl. cong. stat. Nachtblindheit und periventrikulärer Leukomalazie. Der Ophthalmologe 1998;95(suppl 1/1):178.

  • Comments on: "Accuracy of trained rural ophthalmologists versus non-medical image graders in the diagnosis of diabetic retinopathy in rural China"

    Dear Editor,

    We read the article published by McKenna, et al (1) with great interest and laud them on the quality and design of their study. Screening for diabetic retinopathy in rural, low resource settings is the need of the hour, however models which are cost effective, yet provide intensive screening and continuum of care are limited. Keeping this in mind, we feel that there are a few points requiring further clarity in this article.

    The odds-ratio calculated in table 3 displays the significant effect of didactic training on correct diagnosis by rural doctors. However, for the odds-ratio to be calculated, there would have been a comparison group of rural doctors who were not provided didactic training. The numbers of these doctors have not been mentioned, and no details have been provided as to whether they were given any basic level of training related to the program. In the results provided for comparison between rural doctors and the non-medical graders, it has not been made clear whether doctors who had not been provided didactic training were included. In that case, results presented in the study may have been biased towards the non-medical graders.

    In the study, the arbitrator changed the grade for a high percentage of the cases, moreover, 33% of the images were not found to be of adequate quality. Hiring an arbitrator, re-checking the grading and assuring high quality images (2) through standard equipment and trained personnel would drive up...

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  • Response to Letter to the Editor

    To the editor and auther Kivela et al.:

    We thank the authors of the article “Intravitreal Methotrexate for Retinoblastoma” published in Ophthalmology in 2011 for their letter to the editor and adjustment of our discussion in our paper. As was found in your experience, as well as ours, intravitreal chemotherapy plays an important role in the treatment of retinoblastoma outside of its currently accepted use for intravitreal seeds. We look forward to hearing about your continued successful experience with intravitreal melphalan for use beyond intravitreal seeds.

  • Intravitreal chemotherapy in non-vitreal retinoblastoma

    In their report, entitled “Intravitreal chemotherapy in retinoblastoma: expanded use beyond intravitreal seeds“, Abramson and corkers report on the successful use of intravitreal chemotherapy in 52 patients for subretinal seeds and recurrent retinal tumours [1]. They state that, prior to their experience, intravitreal chemotherapy had been used exclusively to control persistent or recurrent vitreous seeding in retinoblastoma that had been refractory to systemic intravenous or intra-arterial chemotherapy.

    In fact, intravitreal chemotherapy as an adjuvant treatment for both subretinal seeds and recurrent retinal tumours, including its use instead of systemic chemotherapy in the setting of chemothermotherapy for small unresponsive primary retinoblastomas, has been in regular use already for a decade at the Ocular Oncology Service, Helsinki University Eye Hospital. Indeed, three of the first four patients that we reported during the congress of the International Society of Ocular Oncology in 2009 [2], and published in 2011 [3], received intravitreal methotrexate for reasons other than vitreous seeds. Subsequent experience with intravitreal chemotherapy with methotrexate and, later, with melphalan has strengthened our initial findings, as does the comprehensive report of Abramson and coworkers.

    1. Abramson DH, Ji X, Francis JH, et al. Intravitreal chemotherapy in retinoblastoma: expanded use beyond intravitreal seeds. Br J Ophthalmol 2018 Jun 6. pii: bjophthalmol-...

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  • Insufficient refractive correction in patients with self-reported age-related macular degeneration

    I commend the authors on an excellent study looking into the stratification of impact of macular degeneration on vision-specific function in patients with early stage AMD vs. late stage AMD. I would like to report similar findings in a United States based population with data gathered from the National Health and and Nutrition Examination Survey 2007-2008 (NHANES) which is a population based cross-sectional survey that represents the non-institutionalized population of the United States.

    As the author's of this study looked at the impact of early and late ARM on vision specific functioning, I assessed a similar question using the NHANES database, specifically looking at whether patients with early and late AMD reported insufficient correction with their currently prescribed glasses or contact lenses, another measure of vision-specific functioning. After survey weighting, the sample represented a US Population of 108,719,628 people with 3.2% of participants (N=3,992) self-reporting a diagnosis of age-related macular degeneration. This represented a weighted sample of 3,479, 028 people. Of these participants reporting a diagnosis of AMD, they had a higher odds of reporting trouble seeing even with correction with glasses or contacts (OR 2.98, Confidence Interval 1.87-4.6). This relationship was held valid when controlling for age, gender, diabetes, race, self reported glaucoma, self reported cataract surgery, retinal exam evidence of retinopathy, and smoking of...

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  • Observations on data analysis on acanthamoeba keratitis

    Dear Editor
    We read the above paper with much interest and welcome the review and analysis of trends in acanthamoeba keratitis – a very important complication from contact lens wear. The paper discusses the incidence of acanthamoeba keratitis at Moorfields Eye Hospital, a large tertiary referral centre.
    We note an incidence of 18.5 cases per annum in 1997-1999, rising to a mean of 50.3 per annum in 2011-2016 and hence has been quite rightly quoted as almost a 3 fold increase in cases.
    We would however suggest some caution when using those figures to state that there is an epidemic at present.
    When one attempts to take into account the fluctuations in numbers of contact lens wearers with the United Kingdom per year and relate that to incidence of acanthamoeba keratitis one has a slightly modified view.1 There has been a steady increase in contact lens wear with figures from the ACLM estimating 4.2 million CL wearers in 2016. A figure has been created showing this relative incidence in a chart format.2
    The figure represents the number of cases diagnosed at Moorfields divided by the number of contact lens users (rising from 1.6 million in 1992 to 4.2 million in 2016). Therefore the mean number of cases when adjusted for CL wearers is 8.5 per year with a standard deviation of 5.8, with 11.8 in 2015 and 14 in 2016.
    Whilst there is still a significant rise in cases, compared to the mainly stable period of 1996-2010, the rates are still lower t...

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  • Optic nerve head analysis to rule out glaucoma

    Dear authors,

    We congratulate the authors for bringing out an ingenious theory regarding pathogenesis of cupping in glaucomatous (GC) and non-glaucomatous (NGC) eyes using this optical coherence tomography (OCT) model. (1) Differentiating a NGC from GC has been a point of discussion for decades and to finally have an objective parameter “anterior laminar depth (ALD)” which appears specific for glaucomatous cupping from this study is indeed beneficial. The authors have used a linear regression model to compare the GC and NGC eyes with healthy controls with adjustment of age, axial length and peripapillary choroidal thickness (PCT). However, it remains to be further studied, how the ALD is to be used for an individual patient, for eg., what cut-off of ALD above which a patient can be labelled as falling in the glaucomatous range. In this regard, we had a doubt regarding inclusion of PCT in ALD calculation. Since the authors have finally adjusted for PCT in the end, we wonder how the results will turn out if they would remove PCT from ALD measurement and compare the remainder measurement (ALD - PCT) between NGC and GC groups.
    Finally, we observed that in this sentence “No significant difference was found in visual field mean deviation (MD) <0.001).”, there is a typographical error and an inadequacy of explanation. No significant difference in visual field MD was indeed seen between NGC and GC groups (p should be >0.99 and not <0.001, as seen in Table...

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