711 e-Letters

  • Preoperative guttae screening of the donor corneas

    We read with great interest the article entitled ‘Prevalence of guttae in the graft following corneal transplantation’ by Nahum et al, published in the May 2015 issue of the British Journal of Ophthalmology [1] . The authors reported the prevalence of cornea guttata postkeratoplasty in a large population of 1116 patients to be 4%. They also found that guttae postkeratoplasty do not negatively affect the visual acuity, endothelial cell density, or graft survival during the initial two postoperative years. The content of this article is important and well put, since this is the first study to reveal the prevalence and sequelae of postkeratoplasty guttae on the corneal graft.

    Based on our clinical experience and on multiple published studies, the prevalence of cornea guttata in the normal population is estimated to be higher than 4% [2]. However, the low prevalence reached by Nahum et al, is explained mainly by the preoperative screening of the donor corneas for guttae, as stated in the article. Therefore, it would be very interesting if the authors can provide an estimation of the percentage of donor corneas that are usually discarded by the guttae screening in their eye bank.

    Up to our knowledge, guttae are very often not detectable using inverted light microscopy, thus guttae screening as a part of the routine examination of the donor corneas is a challenging task. There is only one study performed by Borderie et al in 2001 [3], that aimed to detect the pres...

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  • Re: Özsaygili et al.: The effect of posterior vitreous detachment on aflibercept response in diabetic macular oedema

    We read with interest the study by Özsaygili et al. in which the authors report that the presence or absence of posterior vitreous detachment (PVD) purportedly had no influence on the efficacy of aflibercept intravitreal injections in patients with diabetic macular oedema (DMO). We question the validity of this conclusion since it is known that eyes with attached vitreous require more injections to manage exudative age-related macular degeneration than eyes with PVD.1 This is presumed to be due to interference with macular access by anti-vascular endothelial growth factor (anti-VEGF) by the posterior vitreous cortex. The same mechanism of action could be expected in eyes with DMO. Thus, there may be alternative explanations for the observed lack of an effect of PVD status on the response to aflibercept. We hypothesize that the findings are due to both the unreliable diagnosis of PVD by spectral domain optical coherence tomography (SD-OCT) alone, and the possible presence of vitreoschisis.

    Previous studies have shown that SD-OCT is not a robust way to diagnose PVD, since the positive predictive value is only approximately 50%.2, 3 Rather, ultrasound is the recommended way to detect complete PVD (Figure 1).2 Did Özsaygili et al. perform ultrasound in their patients? If not, they would be unable to determine true PVD status, and the validity of their conclusion needs to be called into question.

    Additionally, it is unclear from the study by Özsaygili et al. wheth...

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  • Response to 'Effect of posterior vitreous detachment on treat-and-extend versus monthly ranibizumab for neovascular age-related macular degeneration

    Dear Editor,

    We read with interest the post-hoc study by Waldstein and colleagues concerning the impact of posterior vitreous detachment (PVD) on the efficacy of anti-VEGF treatment in neovascular age-related macular degeneration (AMD). However, the reliability of spectral-domain optical coherence tomography (SD-OCT) in confirming PVD status, upon which the findings of this study are dependent, is questionable.[1, 2] In particular, OCT is poor at distinguishing between fully attached vitreous and complete PVD.

    Hwang et al recently reported limited sensitivity of SD-OCT in detecting complete PVD when compared to clinical findings at the time of vitrectomy.[1] It was found that among patients awaiting vitrectomy, OCT diagnosis of complete PVD (based on the absence of visible posterior vitreous cortex or a premacular bursa on SD-OCT) had a positive predictive value of just 53% when compared to intra-operative findings.

    PVD remains a clinical diagnosis that is based on the identification of the posterior hyaloid membrane (PHM), a diaphanous, wrinkled film observable during biomicroscopic examination. The Weiss ring which it incorporates is a more variable and less reliable confirmatory sign of PHM detachment from the optic nerve head. The visible PHM is a consistent clinical finding in patients with PVD and correlates histopathologically with a type IV collagen basement membrane which begins life attached to the retina as the internal limiting membrane.[3...

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  • Long Term Stability of Sutured Scleral-fixated Intraocular Lenses

    Dr. Portabella reviewed the stability of 345 consecutive cases of scleral-sutured posterior chamber IOLs retrospectively.1 In discussing sutured scleral-fixated IOLs several main points must be considered: 1) type of suture utilized; 2) length of follow-up; 3) multiple surgeons or single surgeon; 4) type of knot utilized; and 5) reoperation rate.

    This paper by Portabella et al.1 involved use of Prolene (polypropylene) or Mersilene sutures, follow-up with a maximum of 10 years, multiple surgeons, a knot with a single loop through the sclera and around the haptic, and a reoperation rate of 7.2%. The Vote et al study2 reviewed 61 eyes with Prolene sutures, follow-up with a maximum of 10.6 years, multiple surgeons, variable knots, and an extremely high rate of redislocation of 26.2%, which they postulated was due to suture breakage. This high rate of redislocation has not been confirmed in any other study.3,4

    A recent study by Kokame et al3 involved 118 eyes utilizing 10-0 Prolene sutures, a single surgeon, follow-up of up to 24.75 years, a knot with two sutures - one secured to the haptic by a cow-hitch and the other to the sclera with both sutures tied together in a single knot under a scleral flap, and a broken suture rate of 0.5% (1/214 fixation sutures). The maximum follow-up of 24.75 years with stable fixation strongly supports the stability of 10-0 Prolene. Higher rates of redislocations of sutured scleral-fixated IOLs can be due to multiple surgeo...

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  • No vitreous base shaving: one size does not fit all

    Tabandeh and colleagues[1] presented a contrarian viewpoint on the redundancy of scleral-depressed vitreous base shaving: a procedure we have come to take for granted during vitrectomy for retinal detachment (RD). Their excellent outcomes are great news for trainee surgeons, as lens touch is likely during meticulous base dissection in phakic eyes. Sutureless micro-incision vitreous surgery is indeed more secure with residual peripheral vitreous, which plugs the sclerotomy leaks. The authors’ attribution of their high success rate to circumferential laser photocoagulation is validated by a randomized clinical trial.[2] The cases with residual silicone oil (13/89; 15%) should however not be included in the anatomical success; a significant percentage of them re-detach after oil removal.[3]
    The optional use of scleral buckle in this study is confusing. The authors have not specified the choice of buckle (most probably an encircling belt-buckle). Vitreous base-shaving is critical to anatomical success when no encirclage is used.[3] The authors reported no additional benefit from buckling, though it was preferentially performed for complex detachments. We therefore do not have clarity about the one moot issue this study could settle: whether vitrectomy sans base-shaving is good enough for simple RD at least. A recent study suggested that anterior dissection is essential in the presence of posteriorly inserted vitreous base.[4] Did the authors observe this vitreous config...

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  • COVID-19 and immunosuppression in ophthalmic disorders

    The review article by Thng ZX, De Smet MD, Lee CS, et al 1highlights the most intriguing aspects on use of immunosuppressants during and post COVID-19 pandemic. The authors have presented evidences based on various reports in a very well-structured manner and we would like to first thank and congratulate the authors for their work. The review covers the wide range of faculties of medicine where immune suppression is likely to be the main stay of treatment. At the same time, they have also very neatly presented with the “clear cut “ guidelines on the dosing of these various medications at different scenarios and patient status.

    While the article additionally covers the following aspects very well ;

    1) Does the use of immunosuppressive present as an independent risk factor for contracting COVID -19 in patients under them?
    2) Does it affect the severity of COVID -19 ?

    We have few inquiries to make to the authors regarding the use of immunosuppressive in ophthalmology during this difficult time.

    The authors have used the term “high dose steroids” in their article. Firstly, we are curious to understand what would be the considered the criteria to define a “high dosage” of steroid in ophthalmology. From our understanding, it depends upon the class of steroid used and the body weight2 but should we also need to consider the duration of use and cumulative dosage over a stretch of time to define it?

    Also, referring to various public...

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  • RE : Chi et al : Selective Laser Trabeculoplasty Versus Medication for Open-Angle Glaucoma: Systematic Review and Meta-Analysis of Randomised Clinical Trials

    We read with great interest this comparison between selective laser trabeculoplasty (SLT) and medication for Open-Angle Glaucoma (OAG). (1)
    The recent LiGHT trial (2), an important landmark in the management of glaucoma, suggests that SLT represents an ideal first-line treatment option of ocular hypertension (OHT) and open angle glaucoma (OAG) in terms of decreased costs, with similar efficacy and quality of life when comparing to medication. The strength of the trial resides in its methodology, limiting most of the bias seen in the previous retrospective studies on the subject. Despite the fact that their conclusions seemed to be echoing various other authors (3,4) there is still debate as to whether SLT should become a first-line treatment.
    The current powerful meta-analysis by Chi et al on 1229 patients (14 articles, 8 randomized clinical trials), may become the final argument on the debate demonstrating that not only is SLT not inferior to medical therapy in terms of IOP-lowering effect or safety, but it allows for significantly lesser use of medication. (1)
    The longer duration of effect, minimized cost, and safety of SLT are especially important in settings with difficult access to care, such as in developing countries, or in patients with decreased mobility. A recent study on incarcerated patients showed that even when measures are taken to administer and control patients’ adherence to treatment, substantial nonadherence persists. (5)
    It is ri...

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  • Retinal involvement in Covid-19 would probably be missed.

    Dear Editor,
    We have read the clinical case report entitled “Ocular manifestations of a patient hospitalized with a new coronavirus disease confirmed in 2019” by Chen L, et al.1 We congratulate the authors for this important work and wish to share our comment concerning the retinal findings. The authors indicated that Spectral-domain optical coherence tomography (SD-OCT) imaging was normal in both eyes. However, we would like to highlight the presence of hyper-reflective focal points at the level of the internal plexiform layer (IPL) and the ganglion cell layer (GCL). The report later published by Marinho PM, et al. in Lancet on May 12, 2020 "Retinal findings in patients with COVID-19" described the presence of focal hyperreflective dots at the IPL and GCL levels in all patients (24 eyes of 12 patients), which was the first report of SD-OCT retinal abnormalities in patients with COVID 19.2 We compared the two SD-OCT images published by Chen L, et al. to those published by Marinho PM, et al. All images were reviewed by two different retina specialists (NM, RTJH), and our analysis was strongly consistent. We have implemented the algorithm using the Python script3 to adjust the size and resolution of the images, and flipped the C by Marinho PM, et al. using fovea as the reference to obtain comparable images. We overlaid the images published by Chen L, et al. with those published by Marinho PM, et al. We were able to demonstrate that the hyperreflective lesions...

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  • Cat scratch disease retintis on spectral domain optical coherence tomography

    Dear Editor,

    We have read the review article entitled “Ocular complications of cat scratch disease” Johnson A. Br J Ophthalmol 2020;0:1-7. We want to congratulate the author for this important review article, and make some contributions.

    In the review article, it has been indicated that optical coherence tomography (OCT) imaging is of value to monitoring cat scratch disease (CSD), particularly for neuroretinitis and multifocal retinitis.

    We would like to highlight a feature of focal retinitis with spectral domain optical coherence tomography (SD-OCT). Small areas of retinitis, less than 500 microns in diameter, can be seen on OCT imaging. These appear as areas of focal hyper-reflectivity of the inner retinal layers and decreased reflectivity causing a shadow on the outer retinal layers and choroid. This was seen in two patients presenting to our service recently with Bartonella henselae CSD diagnosed clinically and confirmed by positive serology.

    The first case was a 49-year-old Caucasian male who presented with bilateral inflammatory papillitis and multifocal retinitis without a macular star, confirmed with serology as Bartonella henselae (IgG >2048). He had good presenting Snellen visual acuities of 6/5 right, 6/6 left. OCT imaging at acute presentation showed multifocal retinitis seen as small areas retinal hyper-reflectivity of the inner retina with outer retinal disruption. The disease resolved without treatment in 8 months, with...

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  • Neoadjuvant Vismodegib plus Mohs Surgery for Locally Advanced Periocular Basal Cell Carcinoma

    Dear Editor,
    We read with great interest the excellent paper by Sagiv and collegues Ocular preservation with neoadjuvant Vismodegib in patients with locally advanced periocular basal cell carcinoma.(1)
    The article is a great contribution for a topic with a growing, but still limited worldwide experience. Our interest is to discuss the surgical approach after neoadjuvant Vismodegib.

    The authors present a patient with a 5x4cm locally advanced periocular basal cell carcinoma (LAP-BCC) with small nerve perineural invasion (>0.1mm) involving lower eyelid, inner canthus and cheek. The patient showed a significant response after 10 months of Vismodegib. Anyhow, it was clearly a partial response with 3 suspicious areas of BCC after treatment. The authors decided to treat separately each area with surgery, and histology (en face sections) confirmed the presence of tumor in two. The reconstructive outcome was excellent, and at the time of publication the patient was free of disease, 11 months after surgery.

    We agree with the authors, when they consider as a limitation the fact that “surgery did not always include the entire area of the original tumor”.

    Most studies involving smoothened inhibitors thus far have measured clinical tumor shrinkage but not true histologic margin control. Even after a complete clinical response (CCR), there is no way to assure that it will result in a complete histological clearance (CHR).

    Several authors discuss...

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