eLetters

102 e-Letters

published between 2019 and 2022

  • 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.

    References
    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.

  • Short-term real-world outcomes following intravitreal brolucizumab for neovascular AMD: SHIFT study- SAFETY Analysis

    Dear Editor,
    With great excitement, we read the original article titled “Short-term real-world outcomes following intravitreal brolucizumab for neovascular AMD: SHIFT study” by Bulirsch et al.1 We congratulate the authors on their detailed analysis and on adding another important real world data related to brolucizumab usage. As we are still trying to understand the pathogenesis of brolucizumab related immunogenicity and the population at risk,2-4 it would be very helpful for the readers if the authors could share the following information.

    1. Were the 7 eyes in which IOI was recorded have history of any other autoimmune systemic diseases such as arthritis, thyroid abnormalities etc ?
    2. It would be helpful if the authors could clarify if the 4 eyes that had intermediate uveitis and vitreous cells underwent fluorescein angigraphy or wide filed imaging to rule out the possibility of peripheral retinal vasulilits.
    3. It would be helpful for the readers if we could know the indication of using subconjunctival dexamethasone in four cases?
    4. After treatment, were all the patients who had vitritis completely free of cells/inflammation on clinical examination or were they asymptomatic?

    Ashish Sharma, Nilesh Kumar, Nikulaa Parachuri
    Lotus Eye Hospital and Institute, Coimbatore, TN, India

    References
    1. Bulirsch LM, Saßmannshausen M, Nadal J, et al Short-term real-world outcomes following intravitreal brolucizumab for neovas...

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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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  • Re: Lam et al.: Postoperative outcomes of idiopathic epiretinal membrane associated with foveoschisis

    Recently, Lam et al. [1] concluded that patients with macular pucker and foveoschisis had a higher risk of postoperative macular oedema. Since only 5/17 cases had baseline fluorescein angiography it is unclear how they distinguished foveoschisis due to tangential traction, versus cystoid macular edema (CME). Is it possible that postoperative CME was recurrent and not new? In our experience, resolution of foveoschisis takes much longer than the relatively swift resolution in 25% and partial resolution in 68.8% of cases at 1 month, so perhaps CME was a confounding factor. Indeed, Figure 3 appears more like exudative cyst than ‘foveoschisis’.

    Previous studies [2] found that nearly half of patients with macular pucker had multiple centers of retinal contraction which were associated with a higher prevalence of intraretinal cysts and greater macular thickening. Was en face OCT performed to determine the number of contraction centers and its relationship to foveoschisis as well as outcomes of surgery? Additionally, anomalous PVD with vitreoschisis [3] and vitreo-papillary adhesion [4] may be important in the pathogenesis of macular pucker. Did the authors correlate these with foveoschisis and postoperative outcomes?

    There was no significant difference in postoperative visual acuity (VA) between the foveoschisis and control groups, but this may not be the best outcome measure in macular pucker surgery. Studies [5] have shown that quantifying contrast sensitivity fu...

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  • Is it really the same?

    Dear Editor,

    In their review and meta-analysis, Hedengran and coworkers1 report no relative therapeutic benefit of preservative-free (PF) therapies over benzalkonium chloride (BAK)-preserved ones. Should the costlier PF medications therefore be abandoned, or should we question this conclusion?
    Ten of the 16 comparative trials analysed were of short duration, (between 15 and 90 days), the longest taking 6 months. Once-a-day medication was used in each trial, yet the dose response curve for BAK toxicity shows that each additional drop of BAK-containing medication doubles the likelihood of lissamine green corneal staining2 and increases the risk of early failure of glaucoma surgery.3 BAK toxicity is slow in onset increasing over time, due to its continual accumulation within ocular tissues.3 Thus, inconsistencies between experimental studies, which document the harmful effects of BAK and clinical trials, which do not, likely relate to the timing, dosing and duration of glaucoma therapy.4 Two to 12 week trials comparing BAK with alternatively preserved eyedrops, or PF formulations have shown no convincing differences in ocular tolerability, yet the benefits from switching from once-a-day preserved to PF therapy, accrue several months later.4 Longer term transition to alternatively preserved, or PF formulations improves tolerability, and there is good evidence that substituting PF tafluprost for BAK-containing latanoprost significantly improves tolerability.3 So sh...

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  • Dr

    In your interesting paper dealing with the incidence of rhegmatogenous retinal detachment in France, you report the highest incidence rate so far together with Gout et al 1. It is almost twice as high as the incidence found in our area 2. You also report that this incidence was highest in Guadeloupe (28.30±2.74 per 100000 population) and lowest in French Guiana (15.51±3.50 per 100000 population).

    Peters 3 investigated the incidence of RRD in black people and found that it was much lower (0.46/100,000 inhabitants) than in whites. Foos et al. 4 also found that there were no differences in the number of breaks or the proportion/ percentage of vitreous detachments between black and white people, suggesting a stronger adherence in their retinal pigmentary epithelium in the former. Given the fact that black subjects present higher levels of melanin, they have greater resistance against solar radiation, in the same way that they present a lower incidence of non-melanoma skin cancer due to this protective factor 5. Similarly, there is a lower risk of RRD in very dark-colored iris 6 subjects, possibly due to the same reason, as a smaller amount of solar radiation, which has been found to be associated with RRD 7 enters the eye. Taking into account that 70-90% of the population in the French Antilles are mulattoes or creoles (source: indexmundi.com), the lower incidence detected in this geographical location is not surprising. However, we encourage the authors to investigate...

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  • Should the minimum data set be expanded further?

    We read with interest the recent article by Evans et al regarding outcomes in randomised control trial of multifocal lenses in cataract surgery, and their case for development of a core outcome set.1 We wholeheartedly agree that a set of core outcomes would be hugely beneficial to multifocal intraocular lens (MIOL) studies, as there is such variation in multifocal studies currently. This has been commented on by previous Cochrane reviews2 yet there remains no consensus. Such variability makes meaningful comparison between studies difficult.
    Evans’ suggests that the minimum data collected in MIOL studies should be unaided and corrected distance and near LogMAR acuity and contrast sensitivity. Also, the use of a questionnaire for patient reported outcomes that must include questions relating to spectacle independence and halos/glare.
    Whilst we agree with the above measures, we feel that perhaps such a minimum data set may be insufficient particularly as it fails to address intermediate vision. We would recommend the inclusion of a defocus profile that covers distance, intermediate and near ranges. In addition, a standardised method of defocus measurement3 and analysis.4 This could be used as an adjunct to conventional visual acuity testing or indeed as a replacement. MIOLs have different add powers and light distribution profiles; consequently the choice of testing distance for near and intermediate acuity measures has a profound impact on results and hence may n...

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  • Could the current link between PM2.5 and NOx and age-related macular degeneration be confounded by historic exposure to traffic-related lead air pollution?

    Dear Editor,

    Chua et al,[1] used the UK Biobank to identify an association between higher levels of air pollution and increased odds of age-related macular degeneration (AMD). We hypothesize that exposure to high levels of the air pollutant, lead, before 2000, while gasoline contained lead, may play a role in this observed relationship.

    Lead is a toxic heavy metal pollutant that can accumulate in various tissues in the body, including the retina and bones.[2] Lead exposure can induce inflammation and oxidative stress, processes that can be harmful for the eye.[2]

    Various studies have indicated a link between lead exposure and AMD. An autopsy study reported 50% higher lead levels in AMD-affected eyes than controls’ eyes.[2] A doubling of blood lead levels (BLL) in the Beaver Dam Offspring Study was associated with 60% greater risk of 5-year incident AMD.[3] Analyses of a nationally representative Korean survey found 25% higher odds of late AMD per 1 μg/dl increase in BLL.[4]

    In the late 1970s, mean BLLs were 12 μg/dl higher than today, primarily due to exposure from leaded gasoline.[5] BLLs were even higher among those living close to major roads. Once inhaled, lead can deposit in bones, with a half-life of up to 49 years.[5] While the concentration of lead in air decreased dramatically after lead was removed from gasoline, the lead that has accumulated in bones is slowly released, resulting in persistent endogenous exposure which may negativel...

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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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  • Dimness and blur

    I read with interest the paper by Gagrani and colleagues, regarding the self-characterisation of visual field loss by glaucoma patients, and the development of an app to allow this to be measured.1

    The study helps to further understand the experience of glaucoma patients. Their experimental results support the view that patients experience their visual field defects as blur rather than 'black holes'. Hu et al found the most common subjective symptoms in glaucoma were "needing more light" (57%) and "blurry vision" (55%).2 In the study by Gagrani et al., subjects were able to modify both dimness and blur, though in practice they did not choose to use the dimness response at all.

    It is possible that differences in the measurement tools might potentially influence these findings. For example, patients may have found the dim response more difficult to use.

    The potential for this app to allow patients to better understand and self-pictoralise their visual disability is poignant and important. It will be interesting to see whether this novel approach yields similar results when replicated in future.

    References
    1. Gagrani M, Ndulue J, Anderson D, Kedar S, Gulati V, Shepherd J, et al. What do patients with glaucoma see: a novel iPad app to improve glaucoma patient awareness of visual field loss. Br J Ophthalmol. 2020 Nov 20.
    2. Hu CX, Zangalli C, Hsieh M, et al. What do patients with glaucoma see? Visual symptoms...

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