Radial optic neurotomy: a new surgical approach for glaucoma treatment?

Glaucoma is a leading cause of blindness worldwide, characterised by specific visual field defects due to the degeneration of retinal ganglion cells and damage to the optic nerve head (ONH). Elevated intraocular pressure (IOP) is the most important risk factor for glaucoma development. One of the clinical hallmarks of glaucomatous optic neuropathy is the excavation of the ONH, which consists of a progressive posterior displacement of the ONH surface and excavation of the pre-laminar tissues beneath the anterior-most aspect of the scleral canal, known as the anterior scleral ring. Radial optic neurotomy (RON) is a surgical technique that has been proposed for treating central retinal vein occlusion. While the original rationale of RON was the relief of increased tissue pressure within the optic nerve that results from occlusion of the central retinal vein, recent results are discussed here which suggest that by relaxing of the scleral ring of the prelaminar and laminar regions of the ONH, RON may alleviate the IOP-related connective tissue stress, and in turn, prevent the onset and reduce the progression of glaucomatous neuropathy.Fil: Rosenstein, Ruth Estela. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Centro de Estudios Farmacológicos y Botánicos. Universidad de Buenos Aires. Facultad de Medicina. Centro de Estudios Farmacológicos y Botánicos; Argentina. Universidad de Buenos Aires. Facultad de Medicina. Laboratorio de Neuroquímica Retiniana y Oftalmología Experimental; ArgentinaFil: Belforte, Nicolás Adalberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Centro de Estudios Farmacológicos y Botánicos. Universidad de Buenos Aires. Facultad de Medicina. Centro de Estudios Farmacológicos y Botánicos; Argentina. Universidad de Buenos Aires. Facultad de Medicina. Laboratorio de Neuroquímica Retiniana y Oftalmología Experimental; Argentin

Biological Staining and Culturing in Infectious Keratitis: Controversy in Clinical Utility

Infectious keratitis causes significant, financial burden and is only increasing in frequency with contact lens use. Despite this, no retrospective studies, prospective studies, or clinical trials have evaluated the diagnostic validity of clinical guidelines in cases of infectious keratitis. Currently, standard of care recommends that corneal samples be obtained for staining and culturing in select patients showing evidence of corneal ulceration. Ideally, diagnostic information from corneal sampling is thought to help guide therapeutic interventions, prevent disease progression, reduce antibiotic resistance, and decrease overall expenditures for the management and treatment of infectious keratitis. However, current staining and culturing methods are limited by poor sensitivity in non-bacterial cases (i.e. fungal, viral) and lengthy turnaround times, and these methods do not frequently change clinical decision making. Newer fluoroquinolones and broad-spectrum antibiotics resolve the vast majority of cases of infectious keratitis, rendering cultures less essential for management. We studied the clinical utility of obtaining corneal samples for culturing and staining and the need for future research to establish superior diagnostic guidelines for their use in infectious keratitis

Neutrophil to Lymphocyte and Platelet to Lymphocyte Ratios in Normal Tension Glaucoma

Normal tension glaucoma (NTG) is a subtype of glaucoma that occurs at relatively low intraocular pressure levels and results in progressive optic neuropathy. Previous studies display some abnormal immune activity against the optic nerve. Neutrophil to lymphocyte (NLR) and platelet to lymphocyte ratios (PLR) are novel markers for inflammation. Here we evaluated the NLR, PLR, Creactive protein (CRP) and erythrocyte sedimentation rate (ESR) levels in NTG. NLR and PLR were resulted by dividing neutrophil and platelet counts to lymphocyte count respectively. Patients with a history of diabetes mellitus, chronic renal failure, rheumatologic disease, anemia, cancer, cigarette smoking, myocardial infarction and a febrile illness within one month of sampling were excluded from the investigation. In total, the blood samples of 28 NTG and 27control patients were analyzed for the study. There were 11 female (40.7%) and 16 male patients (59.3%) in the control group. The NTG group contained 15 (53.6%) female and 13 (46.4%) male patients. All of the NLR, PLR, ESR and CRP, values of NTG patients were not statistically different from the control group (P = 0.07, P = 0.64 and P = 0.44 respectively). Although previous studies have shown significant differences in NLR and PLR levels in other types of glaucoma, we did not find any significant difference in NTG subjects. Our early report may give insight into the differential diagnosis of NTG. Epub: October 1, 2019

The Association between TGF-β1 G915C (Arg25Pro) Polymorphism and the Development of Primary Open Angle Glaucoma: A Case-Control Study

The purpose of the current study was to identify the potential association between Single Nucleotide Polymorphism (SNP) TGFβ1 +915 (C or G) in codon 25 and Primary Open Angle Glaucoma (POAG). Overall, 88 cases with POAG and a control group of 52 healthy individuals were recruited from the First Ophthalmology Department of Athens University. DNA was isolated from whole blood samples and genotype frequencies for the polymorphism rs1800471 (G915C, Arg25Pro) of the TGF-β1 gene were assessed. Genotype distribution frequencies for the polymorphism rs1800471 (G915C, Arg25Pro) of the TGF-β1 gene were not statistically different between patients with POAG and control subjects. The present study failed to determine any significant genotypic association with POAG, despite the fact that the presence of the C allele was scarcely increased in the POAG when compared with the control group

Intravitreal Bevacizumab in Neovascular Age-Related Macular Degeneration as First Choice: a New Italian Ruling

Background: Intravitreal vascular endothelial growth factor (VEGF) inhibitors represent the mainstay of neovascular age-related macular degeneration (nAMD) treatment. Although bevacizumab has been the first anti-VEGF used in ophthalmology, it is unlicensed for intraocular use. However, the favourable cost-benefit balance has favoured its widespread use. We aimed to present relevant literature regarding the safety profile and the regulatory issues of intravitreal bevacizumab use. Methods: In this narrative review we report relevant studies regarding the safety profile of intravitreal bevacizumab. Expert commentary is provided and an overview of the current scenario and possible future directions discussed. Results: Randomized controlled trials have demonstrated that bevacizumab is not inferior to the licensed anti-VEGF agents showing similar efficacy and safety profiles. However, a significant debate on the regulatory issues of intravitreal bevacizumab used as ‘off label’ first-line treatment in nAMD still persists. Recently, the Regional Health System of Lombardia in Italy decided to only cover the expenses of bevacizumab, forcing clinicians to use bevacizumab as the first choice in the treatment of nAMD. Issues about the practical implications of this decision are discussed. Conclusion: The use of intravitreal bevacizumab as first-line therapy in nAMD remains controversial. Many differences in the regulatory aspects still persist among the European countries and sometimes within the same countries, like Italy. Of note the clinical scenario will be modified in future by the introduction of newly developed anti-VEGF agents and anti-VEGF biosimilars

Ocular biometry characteristics in cataract surgery candidates: A cross-sectional study

Background: This study was conducted to investigate ocular biometry parameters in cataract surgery candidates in northern Tehran, Iran using OA-2000 biometry device. Methods: In this cross-sectional study, values of ocular biometry parameters, including axial length (AL), anterior chamber depth (ACD), mean corneal curvature (mean K), lens thickness (LT), corneal astigmatism (CA), and white-to-white (WTW) of 818 eyes with cataracts, were measured using the OA-2000 biometry device (Tomey, Nagoya, Japan). The participants were divided into six age subgroups, in 10-year intervals. Finally, the values of the biometry parameters were calculated, and the trend of changes was examined for both age and sex subgroups. Results: The mean± standard deviation (SD) of age of the participants was 63.82 ± 13.25 years. Mean ± SD of biometry parameters were as follows: AL, 23.36 ± 1.55 mm; ACD, 3.09 ± 0.40 mm; LT, 4.45 ± 0.55 mm; mean K, 44.51 ± 1.72 D; CA, 1.06 ± 0.94 D; and WTW, 11.81 ± 0.45 mm. Most of the parameters showed significant age-related changes in the total population. There was an increase in LT (P < 0.001) and mean K (P = 0.001), as well as a decrease in AL (P < 0.001) and ACD (P < 0.001) with age. Moreover, AL had a negative negligible correlation with LT (r = -0.24, P < 0.001) and mean K (r = -026, P < 0.001), as well as a weak positive correlation with ACD (r = 0.44, P < 0.001). Conclusions: Our study revealed that the mean values of most biometric parameters varied across age and sex subgroups. Moreover, most of the parameters showed significant age-related changes in the total population

The Correlation between Changes in Biochemical Parameters and Central Macular Thickness in Patients with Non-Proliferative Diabetic Retinopathy

This study aimed at evaluating the correlation between changes in Hemoglobin A1c (HbA1c) and fasting serum lipids, and Central Macular Thickness (CMT) in patients with Non-Proliferative Diabetic Retinopathy (NPDR). In the current research, both eyes of 68 patients with mild or moderate NPDR, without clinically significant macular edema, were studied. Levels of fasting serum lipids, HbAlc, and CMT were measured during the first visit and at the end of the follow-up period (3 months). For statistical analysis, CMTs of each eye were studied and the correlation of changes was investigated. Additionally, the direction of changes in CMT for each eye was determined, and whether the changes in both eyes were symmetrical was investigated. Out of 68 patients, 24 were male and 44 were female. The mean CMT of all eyes was 290.05 ± 48.90 µm during the first visit and 286.80 ± 37.57 µm on the 3rd month follow-up. The mean HbAlc was 8.71 ± 1.82% at first visit to the hospital and the mean HbAlc was 8.39 ± 1.65% at the final visit. Although the changes in HbA1c and CMT during the follow-up period were statistically insignificant, the correlation of these 2 values was statistically significant (p=0.01). However, amongst l3 patients, the CMTs were asymmetrically changed in each eye during the follow-up period. To the best of the author’s knowledge, this was the first study, which indicated a significant correlation in changes of CMT and HbA1c, even amongst patients with low-grade diabetic retinopathy. Demonstration of asymmetric changes in CMT of each treatment-naive eye of the same patient, during changes in systemic conditions, was another important finding of this study

Diagnostic and therapeutic approaches to optic disc pit maculopathy in children

Background: Optic disc pit (ODP) is a rare congenital defect of the optic disc that can lead to maculopathy and gradual visual impairment. This review summarizes our current knowledge on the diagnostic and therapeutic approaches to ODP maculopathy (ODP-M) in children. Methods: A thorough literature search was performed using the PubMed/MEDLINE database from 1960 to 2020. An additional search was conducted using Google Scholar for completeness. Results: ODP-M is characterized by the accumulation of subretinal and/or intraretinal fluid. The exact pathogenetic mechanisms are not fully understood, and the origin of the fluid remains unknown. Although ODP-M is more likely to occur during the third or fourth decade of life, cases of children with serous retinal detachment have been recorded. Early diagnosis of ODP-M and prompt, appropriate management are crucial, particularly in patients of amblyogenic age. In adults, ODP-M may resolve spontaneously, but most cases require surgical intervention to prevent permanent loss of vision. However, the fact that ODP-M may spontaneously resolve in children cannot be ignored. Various surgical methods have been described, including pars plana vitrectomy (PPV) combined with various techniques, including laser photocoagulation, intravitreal gas injection, and macular buckling. Conclusions: PPV remains the mainstay surgical approach for ODP-M. However, ODP-M may differ between children and adults. Children constitute a unique population of patients that require a different and probably more tailor-made approach. Detailed clinical examination, combined with a thorough analysis of retinal imaging, may improve our understanding of the background and pathophysiology of the disease and eventually provide us with new insights into the management of ODP-M in the pediatric population. How to cite this article: Kalogeropoulos D, Asproudis I,  Ch’ng SW, Mitra A, Sharma A, Katsikatsos K, Asproudis C, Kalogeropoulos C. Diagnostic and therapeutic approaches to optic disc pit maculopathy in children. Med Hypothesis Discov Innov Optom.2021 Spring; 2(1): 24-35. DOI: https://doi.org/10.51329/mehdioptometry12

Chitosan-coated contact lens-based ophthalmic drug delivery system to manage Acanthamoeba keratitis: A preliminary hypothesis

Background: Acanthamoeba species can cause devastating contact lens (CL)-related microbial keratitis. Its culture is less sensitive, and little evidence is available for the safety or efficacy profile of medications. Therefore, early diagnosis and optimal treatment remain difficult. The aim of this study was to present the hypothesis that a novel chitosan-coated CL-based ophthalmic drug delivery system has therapeutic and prophylactic effects on acanthamoeba keratitis. Hypothesis: CL-based drug delivery is a popular sustained-release drug delivery that extends the drug release time, thus increasing its bioavailability and treatment efficacy. Chitosan, a derivative of chitin, has antioxidant and broad-spectrum antimicrobial properties against fungi, yeasts, and bacteria. It acts against microbial cells; however, whether its mechanism of action is microbiostatic or microbicidal remains unknown. It exhibits wound healing and film-forming properties. Chitosan composite films permit high transmittance of visible light, making it transparent and therefore desirable for the development of CLs. Chitosan/Ag/ZnO blend films exhibit antimicrobial activities. Further, soft CLs coated with chitosan, sodium hyaluronate, polylysine hydrobromide, and sodium alginate show drug delivery properties and reduced bacterial growth. Recently, concentration-dependent anti-amoebic activities of chitosan and nano-chitosan against the trophozoite and cystic forms of Acanthamoeba have been reported. Based on the existing evidence, we hypothesized that a chitosan-coated CL-based ophthalmic drug delivery system could have therapeutic and prophylactic effects on acanthamoeba keratitis or subsequent endophthalmitis. Conclusions:  CLs or intraocular implants with chitosan-based nanocoatings alone or in combination with routine treatment may be preventive or therapeutic for acanthamoeba keratitis or endophthalmitis. Experimental studies and further clinical trials are required to explore the efficacy and safety profile. Moreover, randomized controlled trials in healthy eyes with soft or hard CLs or orthokeratology lenses for refractive error correction may shed light on the prophylactic effect of this novel drug delivery system. Other forms of ophthalmic drug delivery systems using chitosan-based nanocoatings should be studied additionally

Visual outcomes after management of bilateral cataract and retinal detachment in atopic dermatitis

Background: Atopic dermatitis (AD) is a chronic pruritic inflammatory skin disorder of childhood with a broad spectrum of ocular manifestations, including keratoconjunctivitis, keratoconus, cataract, and rhegmatogenous retinal detachment (RRD). This study was aimed at reporting the visual outcomes in patients with bilateral cataract and RRD in the context of AD. Methods: This was a retrospective, observational case series. A thorough history, clinical features, and surgical management of seven consecutive patients who presented to the Birmingham and Midland Eye Centre with bilateral cataract and RRD secondary to severe AD were investigated. Results: Fourteen eyes of seven patients with AD were analyzed. Twelve of the 14 eyes had cataract (85.7%). Seven patients had anterior or posterior subcapsular cataract (58.3%); 13 of the 14 eyes had RRD (92.8%). Most cases were bilateral or simultaneous (85.7% and 71.4%, respectively). Eight eyes had involvement of the temporal quadrant (61.5%): three eyes had giant retinal tears (23%) and five eyes with proliferative vitreoretinopathy (38.5%). Three eyes underwent scleral buckle surgery with or without cryotherapy (21.4%), and eight eyes had PPV (57.1%) combined with other procedures. Two eyes (15.4%) had persistent RRD postoperatively. The latest recorded postoperative best-corrected distance visual acuity was 6/36 or better in 10 (71.4%) eyes. Conclusions: Temporal RRD was commonly observed in retinal detachment secondary to AD. Surgical repair was often challenging because of proliferative vitreoretinopathy and significant cataract. A further multidisciplinary study involving dermatologists would be helpful in identifying a larger high-risk population for AD and earlier detection of asymptomatic retinal tears or holes, which would allow preventive treatment and limit sight-threatening complications