721 e-Letters

  • Beware of abbreviations: John Cunningham (JC) versus Jamestown Canyon virus

    In their 2008 case report, Muqit, et al. describe a case of “presumptive Jamestown Canyon viral retinitis.”1

    Jamestown Canyon virus is a mosquito-borne, single-stranded, ribonucleic acid (RNA) orthobunyavirus that is endemic throughout much of North America.2,3 Infection with Jamestown Canyon virus may be asymptomatic or may result in a general febrile illness, meningitis, and/or meningoencephalitis.2,3 Beyond the above case report by Muqit, et al.,1 and another review article referencing this case report,4 Jamestown Canyon virus has not been reported to cause retinitis or other ocular manifestations.

    Upon close review of the case report by Muqit, et al.,1 we believe the authors are likely describing a case of John Cunningham (JC) virus (a ubiquitous, double-stranded, deoxyribonucleic acid [DNA] human polyomavirus known to cause progressive multifocal leukoencephalopathy [PML] among the immunocompromised)5-7 rather than Jamestown Canyon virus.

    First, the case patient with viral retinitis had underlying human immunodeficiency virus (HIV) infection and a low CD4 lymphocyte count (240 cells/mm3), making him immunocompromised and susceptible to reactivation of the John Cunningham (JC) virus. Second, the case patient had magnetic resonance imaging (MRI) brain findings (i.e., asymmetric, predominantly posterior, confluent, subcortical white matter hyperintensities involving U-fibers) that are classic for John Cunningham (JC) virus-related PML.6,7 In fact,...

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  • Comment on : Swept source optical coherence tomography angiography in patients treated with hydroxychloroquine: correlation with morphological and functional tests

    We read with great interest the article by Forte et al1, "Swept source optical Coherence tomography Angiography in patients treated with hydroxychloroquine: co-relation of the functional and morphological test." Hydroxychloroquine (HCQ) is a widely used drug for the management of systemic lupus erythematosus and rheumatoid arthritis. Non-invasive tests like optical coherence tomography, optical coherence tomography-angiography, 10-2 visual fields and multifocal ERG (mf-ERG) help in the early detection of the toxicity.2 We would like to highlight here importance of adaptive optics, and various studies done for the early detection of HCQ toxicity. In the study by Forte et al, mf-ERG did not co-relate with the flow changes on OCT-A, however in another observation by Penrose et al (n=6) a depression of signals on multifocal ERG was found in the perifoveal region even when the patients had normal visual acuity and a normal fundus.3Costa et al found significant differences between the micro-perimetry in the patients taking hydroxychloroquine and controls.4 It will be interesting to know the authors take on this. Besides these, adaptive optics is emerging as an important tool to detect the early photo-receptor changes in patients with HCQ toxicity. Adaptive optics help in the direct visualization of the cone mosaic. Stepien et al in their observation on 4 patients observed that adaptive optics showed a loss of cone mosaic in the perifoveal region that corresponded with...

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  • Subclinical Corneal Edema and Contrast Sensitivity in Fuchs Endothelial Corneal Dystrophy

    Eyes with Fuchs endothelial corneal dystrophy (FECD) are known to have reduced contrast vision from increased glare even if high-contrast acuity is not affected.1 In a retrospective study, Augustin and colleagues suggested that corneal guttae without edema contribute to decreased contrast sensitivity, and that such eyes would benefit from Descemet membrane endothelial keratoplasty (DMEK).2 The topic is important because it is unknown whether guttae in the absence of any corneal edema affect vision and therefore whether such eyes truly benefit from DMEK. The authors enrolled eyes with >5 mm of confluent guttae and without edema (modified Krachmer grade 5); however, they did not state their definition of “edema”. In FECD, when corneal edema is not clinically detectable by slit-lamp examination, it can be detected by Scheimpflug tomography.3 A recent study found evidence of subclinical corneal edema in 88% of eyes with FECD grade 5 and almost 40% of eyes with lesser grades of FECD.4 It is therefore highly likely that many of the FECD eyes examined by Augustin and colleagues did in fact have subclinical corneal edema, so can the authors examine the Scheimpflug tomograms of these eyes and report the contrast sensitivity results based on the presence or absence of subclinical edema? This is important because reduced contrast sensitivity might be caused by subclinical edema and not simply by “guttae without edema”, and cornea surgeons should not conclude that it is appr...

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  • Travel burden and clinical presentation of retinoblastoma; they travel more than papers say.

    I have read with interest the paper by Fabian ID et al. “Travel burden and clinical presentation of retinoblastoma”[1]. I acknowledge the efforts conducted by the authors to build a retinoblastoma knowledge based on a large consortium for the first time. Many publications have agreed that the underprivileged socioeconomic situations affect the presentation and outcome of retinoblastoma patients[2, 3]. The measures used in most publications, including the one by Fabian ID et al., are national-level measures. Such socioeconomic measures on the country level affect the roads and travel quality beside family and healthcare giver education and training. A better measure in such cases is an individual level for each family. In developing countries, a vast gap presents between inhabitants letting a country-level measure, not representative. As mentioned in a glimpse in the paper, patients can spend a long time orbiting multiple physicians before targeting the oncology center. On the other side, people with higher economic status can get better healthcare and travel longer distances comfortably and present to centers with early stages.
    Furthermore, Figure 2 shows interestingly similar small catchment areas in Africa; this raised a question on the data that were used for drawing the figure; is it individualized for each center? Additionally, if the analysis depended on the permanent address.
    Egypt’s major pediatric oncology center, which was included in the study, cover...

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  • Response to Travel burden and clinical presentation of retinoblastoma; they travel more than papers say.

    We thank Alfaar for their comment on our paper titled: “Travel burden and clinical presentation of retinoblastoma: analysis of 1024 patients from 43 African countries and 518 patients from 40 European contries”.[1]
    In our paper, we compared the stage of presentation of newly diagnosed retinoblastoma patients from African and European countries and investigated possible associations to the travel distance from home to treatment centre. Our findings suggest that treatment centres in African countries serve patients that reside, on average, in closer proximity to the treatment center than in Europe (186 km average distance travelled in Africa compared to an average distance travelled of 422 km in Europe). In reply to Alfaar’s comment, to produce these numbers, we calculated the average travel distance in a country and then calculated the mean of averages in a continent and compared Africa to Europe.
    The red circles in Figure 2 in our original paper,[1] representing the mean travel distance in a continent, were superimposed on each centre on a scaled map. All red circles in Africa are similar in size (i.e. radius of 186 km) and all in Europe are similar (i.e. radius of 422 km).
    We agree with Alfaar that our analysis has several limitations, some of which are mentioned in our paper and some, rightfully, in his eLetter. In a study, in which patients from over 80 countries in two continents are included, one cannot take into account all considerations, especiall...

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  • Influence of corneal guttae and nuclear cataract on contrast sensitivity

    Reply to the comment on: “Influence of corneal guttae and nuclear cataract on contrast sensitivity”

    We thank Sanjay V Patel for the comments. Patients with Fuchs endothelial corneal dystrophy (FECD) are known to have reduced contrast sensitivity due to corneal edema and guttae. Before the introduction of endothelial keratoplasty, penetrating keratoplasty had been performed mainly in patients with advanced FECD and clinically significant corneal edema. However, as endothelial keratoplasty procedures such as Descemet membrane endothelial keratoplasty can bring excellent visual acuity outcomes, surgery can be performed earlier and even in cases without any clinical corneal edema. Therefore, it has become even more important to detect the causes of visual impairment in patients with FECD. In our retrospective study, we enrolled FECD patients with >5 mm of confluent guttae and no corneal edema (modified Krachmer grade 5). When analyzed by Scheimpflug tomography, our FECD patients showed no difference in the central corneal thickness and corneal volume when compared to the control group of cataract patients without any corneal pathologies.1 Recently, Sun et al. presented a new method to detect subclinical corneal edema in patients with FECD.2,3 The authors analyzed three Scheimpflug tomography pachymetry map and posterior elevation map patterns to detect subclinical edema in FECD patients: loss of regular isopachs, displacement of the thinnest point of the cornea, and...

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  • Factors affecting circumpapillary retinal nerve fibre layer thickness

    McCann et al. reported factors of the associations with intraocular pressure (IOP) and circumpapillary retinal nerve fibre layer (cRNFL) thickness (1). Increased IOP and reduced cRNFL were associated with increased age, myopic refractive error, male sex and hypertension. In addition, Alzheimer's disease was associated with thinner average global cRNFL, and Parkinson's disease (PD) and current smoking status were associated with thicker average global cRNFL, and I present recent information regarding their study in patients with PD.

    Murueta-Goyena et al. reported the association between the changes of retinal thickness and their predictive value as biomarkers of disease progression in idiopathic PD (2). The authors used macular ganglion-inner plexiform layer complex (mGCIPL) and peripapillary retinal nerve fiber layer (pRNFL) thickness reduction rates, and the Montreal Cognitive Assessment (MoCA) questionnaire was also applied. The adjusted relative risks of lower parafoveal mGCIPL and pRNFL thickness at baseline for an increased risk of cognitive decline at 3 years significantly increased. This means that reduced retinal thickness is a risk factor of cognitive impairment in patients with PD. McCann et al. did not evaluate cRNFL in PD patients with cognitive impairment, and I suppose that progression of cognitive impairment in patients with PD might accelerate reduction of average global cRNFL.

    Second, Sung et al. also investigated the association be...

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  • Re: Characteristics of endothelial corneal transplant rejection following immunisation with SARS-CoV-2 messenger RNA vaccine

    Dear Editor,

    Corneal graft rejection following vaccination was first reported in 1988 by T L Steinemann, B H Koffler and C D Jennings [1]. This article is missing from Table 1, “Summary of reported cases of corneal graft rejection”. As it is the first published study to describe this temporal association, it merits mention.

    In regards to preventative measures, we recommend thoroughly counseling patients with grafts. They should be educated on the salient warning signs of rejection including pain, redness, blurred vision, and irritation. Patients should also be informed that COVID-19 vaccination may pose a risk to the viability of their corneal grafts. We recommend prophylactically increasing topical steroids for 3-4 weeks around the time of each vaccination.

    1. Steinemann TL, Koffler BH, Jennings CD. Corneal allograft rejection following immunization. Am J Ophthalmol. 1988 Nov 15;106(5):575-8. doi: 10.1016/0002-9394(88)90588-0. PMID: 3056015.

  • Extended Utility Domains for Health Economics Evaluations in Ophthalmology: A call to action

    Atik et al (BJOhttps://bjo.bmj.com/content/105/5/602) have done an excellent job of summarizing the current state of the art for conducting health economic evaluations in ophthalmology. Not surprisingly, however, such tools and techniques were originally designed to address broader questions of healthcare funding and resource allocation across many disparate clinical areas. As such, the general use case was very far removed from ophthalmology. This is relevant as a central component is the calculation of the utility parameters used, particularly in cost-effectiveness calculations (1). At present, the standard default utility measure remains the EQ5D, which does not prima facie include a vision specific domain (2). Rather, a “Vision Bolt-On” to the EQ5D which asks patients whether they “Have no problems seeing”; “Have some problem seeing”; or “Have extreme problems seeing” is proposed for increasing the precision of the utility score derived from patients for ophthalmic interventions (3). Unfortunately, the “Vision Bolt On” while theoretically increasing the discriminating power of the EQ-5D has not been widely adopted in economic evaluations conducted in ophthalmology (3-4). Moreover, as currently configured, the “Vision Bolt On” questions fail to adequately account for the clinical differences, say between central or fine reading vision which may be more relevant in patients with age-related macular degeneration, versus...

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  • Benzalkonium chloride (BAK)-preserved anti-glaucoma drops elicits Ocular surface inflammation in naïve glaucomatous patients starting 6 months onwards

    Dear Editor:

    We welcome the recent meta-analysis by Hedengran and co-workers in the British Journal of Ophthalmology (BJO).1 This study compared the efficacy and safety of benzalkonium chloride (BAK)-preserved eye drops with alternatively preserved (AP) and preservative-free (PF) eye drops. The meta-analysis was conducted on 16 studies that range from 15 days to 6 months of study duration. Change in IOP in BAK vs AP and PF groups was meta-analysed as the primary outcome. Conjunctival hyperaemia, ocular hyperaemia, total ocular adverse effects (AE), and TBUT were also meta-analysed. The authors found no evidence of significant change in IOP and conjunctival hyperaemia between BAK vs AP and PF treatment groups. The authors concluded that the main reason for detecting no clinical differences between the groups was related to the lack of long-term clinical studies on the safety of BAK vs AP and PF eye drops. We are in consensus with Kontas AG et al., comments on the deficiencies of this meta-analysis.

    We do not agree to the conclusion, “BAK-containing and PF medications do not differ with respect to tolerability and therapy outcome”. We would like to direct the authors and readers to our recently published study in the journal, Clinical and Experimental Ophthalmology (CEO), which involved the randomised evaluation of the inflammatory effects of PF vs BAK and PF vs polyquad (PQ)-preserved eye drops in naïve glaucomatous patients over the period of 24 months.2 We p...

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