77 e-Letters

published between 2020 and 2023

  • Use of standard surgical tables for AACE

    26th September 2023

    Dear Editor,
    We read with great interest the study conducted by Yu X et al.1 comparing the efficacy of augmented surgical doses of surgery and Botulinum Toxin A injection for Acute acquired concomitant esotropia (AACE).
    AACE has been on the rise with the advent of digital education for children, smartphones and change in lifestyles for both adults and children and hence this work is of particular interest to us.
    We wish to report outcomes from our unpublished series of acquired esotropia. We retrospectively analyzed 29 patients of AACE, over a 17 month period between April 2022 and September 2023. As per protocol, we used surgical doses suggested by standard tables and did not use augmentation. The mean angle of deviation was 43.09  9.32 PD at 6m and 46.31 9.8 PD at 33cm preoperatively. The mean dose response without augmentation we achieved was 3.12 0.62 PD/mm and we achieved surgical success in 28 patients. The post operative final angles of deviation were 3.33  5.81 PD at 6m and 4.05-6.64 PD at 33cm at the last follow up. We used similar criteria of surgical success as Yu X et al.
    Kim et al also report successful surgical outcomes in their subset of AACE patients using standard doses from Park’s tables.3
    Augmented surgery has also been done by either increasing the amount of recession or resection and has resulted in good motor and sensory outcomes4,5
    Yu et al recommend augmenting their surgical dose by...

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  • Pachychoroid and vitelliform deposits

    Dear Editor, we read with interest the study of Hilely and coworkers, describing a new condition which they referred to as pachyvitelliform maculopathy. Their study clearly demonstrates the association between pachychoroid features and adult vitelliform lesions (AVLs).1 Two previous reports by our teams may stregthen their hypothesis of a relationship between the two conditions. In cuticular drusen, we have shown that vitelliform detachments occur significantly more often in eyes with a thick choroid, and we suggested that the choroidal vasculature could play a role in the occurrence of macular detachments in patients with cuticular drusen, leading to accumulation of photreceptors debris and deposits.2 More recently, we report a series of 49 eyes with hyperreflective vertical lines diagnosed on B-scans of spectral-domain optical coherence tomography. Twenty-four eyes presented with AVLs related to adult vitelliform dystrophy or pattern dystrophy. We were surprised that, in 14 cases out of 24, signs of pachychoroid were present. We suggested that further studies were needed to better understand this relationship.3 So we fully agree in that the pachychoroid syndrome may interfere with the metabolism of the retinal pigment epithelium and the phagocytosis process, leading to accumulation of photoreceptors debris. We really thank Hilely and coworkers for their convincing step towards a better recognition of this curious association.

    Salomon Y Cohen, A Gaudric, Sarah Mrej...

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  • Rapid response to "Pachyvitelliform maculopathy: optical coherence tomography analysis of a new entity"

    We read with considerable attention the manuscript by Hilely et al. entitled “Pachyvitelliform maculopathy: an optical coherence tomography analysis of a novel entity.”1 We would like to compliment the Authors on their great effort and excellent figures.
    Hilely and associated introduced a novel clinical entity named pachyvitelliform maculopathy (PVM). It consisted of the association between acquired vitelliform lesion (AVL) and pachychoroid disease spectrum (PDS) features, including pachychoroid (choroidal thickness > 250 μm), pachyvessels (dilated Haller vessels), and inner choroid thinning. In detail, a yellowish hyperreflective lesion overlayed a thick choroid and pachyvessels. In contrast to other forms PDS,2 PVM displayed no subretinal (SRF) or intraretinal fluid (IRF) and neovascularization. Furthermore, cases of pachychoroid and drusen (medium, large, cuticular, pseudo reticular, and subretinal drusenoid deposits) were excluded. This condition was described in 60 years older subjects with electro-oculogram within normal range and with a negative genetic test, although performed in a minority of the cohort.
    We would like to have the thoughts about the following issue that Hilely and colleagues ought to address. Although the Authors stated that this was the first description of PVM, previous papers discussed the aforementioned association between PDS and vitelliform lesions. In detail, Spaide described three cases (two monoliteral, and one bilateral) o...

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  • Authors' reply

    We thank Dr. Carkeet for his comments on our paper,1 which is now over 15 years old.

    As discussed with Dr. Carkeet in personal correspondence recently, the discrepancy between his results and ours occurred because we simplified the 1 exam/year and 3 exam/years conditions by linearly scaling the outputs from the 2 exam/year condition. We repeated the simulations under the conditions Dr. Carkeet has outlined, and we agree with the result. The simulations yield approximately the same time required to detect the various rates of change for 2 exams per year, and slightly different values for 1 and 3 exams per year. He has pointed out discrepancies in the 1 and 3 exam per year conditions which appear large only in extreme conditions and are not realistic in clinical practice, for example, detecting a -0.25 dB/y change with high variability, where we estimated 30 years and Dr. Carkeet estimated 18 years.

    In the final analysis simulations are only simulations that can be made with conditions assumed to reflect reality. The precision with which these estimates is made can be low. Ultimately, the message in our paper was that it takes a long time to detect a small amount of change if visual field results are variable and the testing frequency is low.

    Our paper has been used to inform guidelines from various organizations and is based on one of the key messages of the paper, i.e., that ruling out fast progression (worse -2 dB/y or worse) requires 6 visual...

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  • Response to Dr Velez-Montoya and colleagues' comment

    To the Editor:

    We thank Dr Velez-Montoya and colleagues for their interest in our study.1 We reported that there was an increase in the prevalence of endophthalmitis after vitrectomy in Japan and found that it was probably related to the face masks during the COVID period.2 Although the cause for the increase definitively determined, we need to report these findings to the ophthalmologic community to alert them of this possibility.

    First, we address the indicated point, “the definition of postoperative endophthalmitis was not rigorous”. We used the definition of the Endophthalmitis Vitrectomy Study group.3 Although this definition is relatively old, many subsequent studies have used it, and it has the advantage that our findings could be compared to these other studies with the same definition.

    They also stated that the latest studies have shown that the sclerotomies after a pars plana vitrectomy seal within 15 days after the surgery even after a suture-less closure. Thus, the site of the incision was unlikely the entry port for the infectious micro-organisms after that time. This is generally true but the cause of infectious endophthalmitis after vitrectomy is complex. Because the cause of infectious endophthalmitis is varied, it is not surprising that anything can happen with postoperative endophthalmitis. For example, it is possible for a patient to inadvertently touch the eye in the early postoperative period and cause the incision to open. Once...

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  • Calculation errors overemphasise the value of increasing visual field test frequency.

    Chauhan and co-workers [1] have provided Table 1, showing times taken to detect significant field progression with 80% power, based on a number of modelling parameters: frequency of examinations, rate of field progression, intrasession variability of field assessment. They have also provided Table 2 showing the number of annual eye examinations required to detect different total visual field changes, for different time periods, and for moderate variability. I have checked the calculations of Chauhan and co-workers, using Monte Carlo modelling, assuming a one-tailed significance value of 0.025. Of the 36 outcome values in Table 1, 33 are incorrect. Of the 12 outcome values in Table 2, 11 are incorrect.

    Chauhan and co-workers have made 2 main errors in their calculations for Table 1. The first is in applying their estimates of power. The curves shown in Figure 2 (statistical power plotted against number of field examinations) are appropriate for the case of 2 field examinations per year, but Chauhan and co-workers appear to have incorrectly also used them for the cases of 1 examination per year and 3 examinations per year. Separate sets of curves should have been calculated for those conditions. The effect on Table 1 is that the time taken to detect a field change is incorrectly reported as being inversely proportional to the number of examinations per year. This anomalous relationship was commented on by Albert Alm in his 2008 Rapid Response, “Is a field every 4...

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  • Letter to the Editor: Non-invasive intracranial pressure estimation using ultrasonographic measurement of area of optic nerve subarachnoid space

    Dear Editor:

    We read the paper on non-invasive intracranial pressure determination by Zhang et al(1) with great interest and hope. We fully agree that the search for non-invasive intracranial pressure (ICP) evaluations is of high importance and should be continued. The Bland-Altman plot showing the difference between predicted and intracranially measured pressure looks very impressive. There are, however, still a few points and limits we would like to address concerning the anatomy of the optic nerve, the optic canal, and the basic concept the authors used.

    Cerebrospinal fluid (CSF) from the intracranial subarachnoid spaces and the subarachnoid space of the optic nerve (SAS -ON) communicate via the optic canal. Using three-dimensional reconstruction of the optic canal in normal tension glaucoma (NTG) patients, this was found to be narrower than in an age-related cohort of normals,(2) thus questioning the patency of the CSF pathway between the pituitary cistern and the SAS-ON. Further, optic canal dimensions in a normal population are quite variable amongst individuals, and even between orbits within the same individual.(3) These facts largely influence the results the authors present. Further, studies in patients with NTG and patients with elevated ICP (such as patients with idiopathic intracranial hypertension) were shown to have developed an optic nerve sheath compartment syndrome. In such cases, the CSF dynamics between the intracranial CSF and the CSF in...

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  • Quality of the coding and data on AMD

    We read with great interest the article of Gokhale et al [1] on their retrospective study of metformin use and risk of age-related macular degeneration (AMD) in individuals with type 2 diabetes mellitus (T2DM). In this study Gokhale and colleagues used data derived from IQVIA Medical Research Data (IMRD-UK), formerly known as The Health Improvement Network (THIN), and found no change in AMD risk in those taking metformin.

    An issue with this study is the quality of the GP coding and data on AMD. The authors cite a validation study of THIN data [2] but this study only validated cases identified as having AMD. There was no validation of the quality of data on the absence of AMD. So, the confirmation of positives was high (confirmed AMD cases quoted as 97%) but the false negative rate, is unknown. Also, the validation was by an ophthalmologist reviewing all the GP data, not using recognised diagnostic criteria or a grading scheme for AMD. Furthermore, the authors included a code for “drusen” into their AMD group which was not a code included in the validation study by Vassilev et al [2]. It is likely that this code includes patients with common physiological drusen and not an AMD diagnosis.

    We have previously performed a systematic review and meta-analysis [3] of five studies [4–8] on the relationship between metformin use and AMD, which we have now updated to include Gokhale et al [1] and Jiang et al [9]. Including their data, we found a beneficial odds ratio of...

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  • RE: Association of lipid-lowering drugs and antidiabetic drugs with age-related macular degeneration: a meta-analysis in Europeans

    Mauschitz et al. (1) conducted a meta-analysis to investigate the association of systemic medications with age-related macular degeneration (AMD) in the general population. A pooled odds ratios (95% confidence intervals [CIs]) of lipid-lowering drugs (LLD) and antidiabetic drugs for any AMD were 0.85 (0.79 to 0.91) and 0.78 (0.66 to 0.91), respectively. In contrast, late AMD was not significantly associated with systemic medications. There is an information that antidiabetics, lipid-lowering agents, and antioxidants could theoretically be repurposed for AMD treatment (2). I present information regarding the effect of antidiabetic medications on the risk of AMD.

    Blitzer et al. (3) conducted a case-control study and metformin use was significantly associated with reduced odds of AMD, presenting dose dependent manner. But metformin did not have an effect of protecting diabetic retinopathy. In contrast, Gokhale et al. (4) conducted a retrospective cohort study to evaluate the effect of metformin on the risk reduction of AMD. The adjusted hazard ratio (95% CI) of patients prescribed metformin (with or without other antidiabetic medications) against those prescribed any other antidiabetic medication only for AMD was 1.02 (0.92 to 1.12). Vergroesen et al. (5) conducted a cohort study and a lower risk of AMD was not observed in patients with metformin, but other diabetes medication was significantly associated with a lower risk of AMD.

    Anyway, clinical trials are nee...

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  • Mr

    The paper advises that the population inspected was predominately of white background and is looking to find ways of expanding its knowledge of non-white ethnicity within the sphere of retina testing. Within the following paper : Ethnicity and Type 2 diabetes in the UK by
    L. M. Goff; it states that the prevalence of Type 2 diabetes within the non-white community is particularly high. a quote from this paper:
    "Among minority ethnic communities, the prevalence is alarmingly high, approximately three to five times higher than in the white British population. "
    Which brings me to my response: All UK Type 2 diabetics are offered eye screening during which the retina is photographed every year. These digital photographs are examined by medical staff looking for vein bleeding and are held by the NHS. Given the hign incidence of Type 2 diabetes in non-white citizens a very large number of these records will be available and so allow a useful extension to the work done by Professor Rudnicka.