An overview of retinal light damage models for preclinical studies on age-related macular degeneration: identifying molecular hallmarks and therapeutic targets.

Age-related macular degeneration (AMD) is a complex, multifactorial disease leading to progressive and irreversible retinal degeneration, whose pathogenesis has not been fully elucidated yet. Due to the complexity and to the multiple features of the disease, many efforts have been made to develop animal models which faithfully reproduce the overall AMD hallmarks or that are able to mimic the different AMD stages. In this context, light damage (LD) rodent models of AMD represent a suitable and reliable approach to mimic the different AMD forms (dry, wet and geographic atrophy) while maintaining the time-dependent progression of the disease. In this review, we comprehensively reported how the LD paradigms reproduce the main features of human AMD. We discuss the capability of these models to broaden the knowledge in AMD research, with a focus on the mechanisms and the molecular hallmarks underlying the pathogenesis of the disease. We also critically revise the remaining challenges and future directions for the use of LD models.

Proliferative Vitreoretinopathy: A Reappraisal.

Proliferative vitreoretinopathy (PVR) remains the main cause of failure after retinal detachment (RD) surgery. Despite the development of modern technologies and sophisticated techniques for the management of RD, the growth of fibrocellular membranes within the vitreous cavity and on both sides of the retinal surface, as well as intraretinal fibrosis, can compromise surgical outcomes. Since 1983, when the term PVR was coined by the Retina Society, a lot of knowledge has been obtained about the physiopathology and risk factors of PVR, but, despite the proposal of a lot of therapeutic challenges, surgical skills seem to be the only effective way to manage PVR complications.

Topical treatment of dupilumab-associated refractory conjunctivitis and keratitis.

PURPOSE: To report 3 cases of severe dupilumab-related conjunctivitis and keratitis topical treatment. OBSERVATION: Description, management, and outcomes of dupilumab-related refractory conjunctivitis associated with punctate keratitis.Three patients with atopic dermatitis (AD) experiencing severe ophthalmic complications following dupilumab treatment were referred to us when conventional management methods failed. We treated them topical and external pimecrolimus 10 mg/g cream to the eyelids. The patients showed substantial clinical remission within 10 days. CONCLUSIONS AND IMPORTANCE: Those cases are remarkable as a drug applied externally to the eyelid skin successfully treated underlying conjunctivitis and punctate keratitis. The complete clinical remission suggests that pimecrolimus applied topically to the eyelid skin is a safe and effective delivery route. The resolution of the keratitis and conjunctivitis presumably represents either a contiguous effect of the improvement of the cutaneous inflammation, or the effect of transcutaneous pimecrolimus penetration through the eyelid.Further studies are needed to support the use of this drug for dupilumab-associated conjunctivitis.

Face Mask-Related Ocular Surface Modifications During COVID-19 Pandemic: A Clinical, In Vivo Confocal Microscopy, and Immune-Cytology Study.

Purpose: The purpose of this study was to describe the face mask (FM)-related ocular surface changes using clinical tests, in vivo confocal microscopy (IVCM) and impression cytology (IC), and to investigate the Dry Eye-related Quality of life Score (DEQS). Methods: Sixty-six patients with dry eye disease (DED) and 62 healthy subjects (group 2) using FM were enrolled. Groups were divided into: groups 1A and 2A: < 3 hours of FM wear; groups 1B and 2B: 3 to 6 hours; and groups 1C and 2C: > 6 hours. Patients underwent DEQS questionnaire, break-up time (BUT), Schirmer test I (STI), fluorescein and lissamine staining (FS and LS), IVCM to determine corneal dendritic cell density (DCD) and goblet cell density (GCD), and IC to measure HLA-DR, at baseline and after 3 months. Results: FM use duration before enrollment was 27 ± 2.3 and 30 ± 4.1 (days ± SD) for groups 1 and 2 (P > 0.05). After 3 months, DEQS worsened in groups 1B and 1C, STI in groups 1A to 1C, FS and LS in group 1C (P < 0.05); in controls, BUT and FS worsened only in group 2C (P < 0.05). DCD significantly increased in groups 1A to 1C and HLA-DR in groups 1B and 1C (P < 0.05), whereas GCD did not significantly change. DCD and HLA-DR increased only in group 2C (P < 0.05). DEQS significantly correlated with DCD (P = 0.05, r = 0.698; P < 0.001, r = 0.832) and HLA-DR (P = 0.043, r = -0.687; P < 0.001, r = 0.861) at baseline and 3 months. Conclusions: Use of FM increases ocular surface inflammation and negatively impacts the quality of life in patients with DED. Translational Relevance: The study of the prolonged use of FM effects may be relevant to managing DED.

Treatment of Capecitabine Corneal Side Effects With Autologous Blood-derived Serum Eye Drops.

BACKGROUND/AIM: To describe the clinical progress and management of ocular side effects in a 35-year-old patient with metastatic breast cancer who underwent oral chemotherapy with capecitabine and lapatinib. MATERIALS AND METHODS: Slit lamp evaluation revealed bilateral perikeratic hyperemia, perilimbal conjunctival edema associated with corneal marginal infiltrates and epithelial and anterior stromal defects in both eyes. Slit lamp examination, in vivo confocal microscopy and anterior-segment optical coherence tomography were highly suggestive for limbal stem cell deficiency. The decision to administer autologous blood- derived serum eye drops was made. RESULTS: Following administration of autologous blood-derived serum eye drops, corneal marginal infiltrates, epithelial and stromal defects significantly regressed in both eyes after only 10 days. Chemotherapy was resumed and serum eye drops were prescribed simultaneously. CONCLUSION: Autologous blood-derived serum eye drops may be an adequate therapeutic choice for bilateral corneal lesions detected as ocular side effects of capecitabine.

The Impact of Oxidative Stress on Blood-Retinal Barrier Physiology in Age-Related Macular Degeneration.

The blood retinal barrier (BRB) is a fundamental eye component, whose function is to select the flow of molecules from the blood to the retina and vice-versa, and its integrity allows the maintenance of a finely regulated microenvironment. The outer BRB, composed by the choriocapillaris, the Bruch's membrane, and the retinal pigment epithelium, undergoes structural and functional changes in age-related macular degeneration (AMD), the leading cause of blindness worldwide. BRB alterations lead to retinal dysfunction and neurodegeneration. Several risk factors have been associated with AMD onset in the past decades and oxidative stress is widely recognized as a key factor, even if the exact AMD pathophysiology has not been exactly elucidated yet. The present review describes the BRB physiology, the BRB changes occurring in AMD, the role of oxidative stress in AMD with a focus on the outer BRB structures. Moreover, we propose the use of cerium oxide nanoparticles as a new powerful anti-oxidant agent to combat AMD, based on the relevant existing data which demonstrated their beneficial effects in protecting the outer BRB in animal models of AMD.

Ophthalmic Applications of Cerium Oxide Nanoparticles.

Cerium oxide nanoparticles (CeO2-NPs; or nanoceria) have been largely studied for biomedical applications due to their peculiar auto-regenerative antioxidant activity. This review focuses on ophthalmic applications of nanoceria. Many in vivo data indicate that nanoceria protect the retina from neurodegeneration. In particular, they have been tested in animal models of age-related macular degeneration and retinitis pigmentosa and their neuroprotective properties have been shown to persist for a long time, without any collateral effects. In vitro cytotoxicity studies have shown that CeO2-NPs could be safe for lens cells and could represent a new therapy for cataract treatment, but further studies are needed. To date, different pharmaceutical formulations based on nanoceria have been created looking at future clinical ophthalmic applications, such as water-soluble nanoceria, glycol chitosan-coated ceria nanoparticles (GCCNPs), and alginate-gelatin hydrogel loaded GCCNPs. GCCNPs were also effective in preventing choroidal neovascularization in vivo. Based on the nanosize of nanoceria, corneal permeation could be achieved to allow topical treatment of nanoceria. PEGylation and encapsulation in liposomes represent the main strategies to support corneal permeation, without altering nanoceria chemical-physical properties. Based on their great antioxidant properties, safety, and nanosize, nanoceria represent a new potential therapeutic for the treatment of several eye disorders.

Anatomical and functional changes after dexamethasone implant and ranibizumab in diabetic macular edema: a retrospective cohort study.

AIM: To investigate the efficacy and safety of ranibizumab (RZB group) and dexamethasone implant (DEX group) intravitreal treatments in patients with treatment-naïve center involved diabetic macular edema (DME) by means of functional and morphological assessments. METHODS: This retrospective cohort study included 50 eyes of 50 patients with DME treated either with RBZ or DEX. Best-corrected visual acuity (BCVA) and microperimetry were evaluated at baseline and during a 6-month follow-up. In addition, central macular thickness (CMT) by means of structural optical coherence tomography (OCT) and retinal capillary plexus density and choriocapillary density by means of OCT angiography were assessed in all cases. RESULTS: Functional and morphological parameters significantly improved during the study period in both groups. BCVA improved significantly in both groups with a greater increase in the DEX group compared to the RBZ group (P=0.030). Microperimetry significantly differed during follow-up between the two treatments (P=0.031). In both groups CMT significantly decreased (P<0.001) without statistically significant differences between the two groups. A statistically significant increase of deep capillary plexus density was detected in both groups at 30d after therapy. The retreatment rate was 0.70±0.10 and 0.65±0.10 in the RBZ group and 0.65±0.10 and 0.50±0.11 in DEX group at 120 and 180d respectively. Two out of 25 patients in DEX group showed intraocular pressure increase requiring hypotonic eye drops. CONCLUSION: Both treatments are very effective for DME treatment during 6mo of follow-up with a lower retreatment rate in DEX group.

Optical Coherence Tomography of Choroid in Common Neurological Diseases.

The choroid is involved directly and indirectly in many pathological conditions such as age-related macular degeneration, myopia-related chorioretinal atrophy and central serous chorioretinopathy. Optical coherence tomography (OCT) has gradually become a fundamental part of modern resources in the hands of ophthalmologists. The enhanced depth imaging technique and swept-source OCT make a great contribution to conventional in vivo choroid assessment. This review focuses on the most common neurological conditions in which choroid assessment by OCT may provide help in early diagnosis and be used as an interdisciplinary follow-up tool. In order to avoid evaluation biases and misdiagnosis, the main and most common physiological and para-physiological conditions in which the choroid may show alterations are also reviewed.

Diagnostic capability of optic nerve head rim width and retinal nerve fiber thickness in open-angle glaucoma.

PURPOSE: This study was performed to test the diagnostic capability of the minimum rim width compared to peripapillary retinal nerve fiber layer thickness in patients with glaucoma. METHODS: A case control, observer masked study, was conducted. Minimum rim width and retinal nerve fiber layer thickness were assessed using the patient-specific axis traced between fovea-to-Bruch's membrane opening center axis. For both minimum rim width and retinal nerve fiber layer thickness, the regionalization in six sectors (nasal, superior-nasal, superior-temporal, temporal, inferior-temporal, and inferior-nasal) was analyzed. Eyes with at least one sector with value below the 5% or 1% normative limit of the optical coherence tomography normative database were classified as glaucomatous. The area under the receiver operator characteristic curve, the accuracy, sensitivity, specificity, and predictive positive and negative values were calculated for both minimum rim width and retinal nerve fiber layer thickness. RESULTS: A total of 118 eyes of 118 Caucasian subjects (80 eyes with open-angle glaucoma and 38 control eyes) were enrolled in the study. Accuracy, sensitivity, and specificity were 79.7%, 77.5%, and 84.2%, respectively, for minimum rim width and 84.7%, 82.5%, and 89.5% for retinal nerve fiber layer thickness. The positive predictive values were 0.91% and 0.94% for minimum rim width and retinal nerve fiber layer thickness, respectively, whereas the negative predictive values were 0.64% and 0.70%. The area under the receiver operator characteristic curve was 0.892 for minimum rim width and 0.938 for retinal nerve fiber layer thickness. CONCLUSION: Our results indicated that the sector analysis based on Bruch's membrane opening and fovea to disk alignment is able to detect glaucomatous defects, and that Bruch's membrane opening minimum rim width and retinal nerve fiber layer thickness showed equivalent diagnostic ability.

In Vivo Analysis of Prostaglandins-induced Ocular Surface and Periocular Adnexa Modifications in Patients with Glaucoma.

BACKGROUND/AIM: Prostaglandin analogues (PGAs) are a first-line medical treatment for glaucoma because of their powerful intraocular pressure (IOP) lowering effect, few systemic side-effects (SEs), and the once daily administration. Despite the high systemic safety profile, the chronic use of PGAs may induce periocular and ocular surface (OS)-related side effects, which affect a significant proportion of glaucomatous patients. In this review, we summarize the current knowledge about SEs of PGAs on periocular structures and OS, and their implications in clinical practice. MATERIALS AND METHODS: A comprehensive literature search on the PubMed platform was performed. Two hundred fifty articles fulfilling key words were identified, of which 180 were excluded since they did not concern the effects of PGAs on the periocular tissues and OS, or because of their limited relevance. The following key words were used and combined, to narrow-down the literature: "prostaglandin" and "ocular surface," which identified 184 unique publications, of which 68 were selected; "prostaglandin" and "periocular" which identified 46 unique publications, of which 11 were selected. An additional search was conducted using "prostaglandin" and "Meibomian glands (MGs)", which identified twenty unique publications, of which 8 were selected. Thus, a total of 70 articles were chosen based on their relevance and were included in this review. RESULTS: Prostaglandin-associated peri-orbitopathy, skin pigmentation and hypertrichosis, eyelash growth, and MGs dysfunction are the most frequent modifications of periocular tissues. They are induced by the tissue accumulation of PGAs, and FP receptor stimulation. Without preservatives, PGAs act as stimulators of conjunctival goblet cells, which are the main source of ocular surface mucoproteins, and seem to increase conjunctival epithelium microcysts proposed as in vivo hallmark of the trans-scleral aqueous humour outflow. Additional PGA-induced modifications can be recognized in the cornea, corneo-scleral limbus, conjunctival stroma and, conjunctiva-associated lymphoid tissue, mainly appearing as inflammatory changes. OS epithelia desquamation, chemosis, apoptosis, dendritic cell activation, conjunctival or episcleral vasodilation, and sub-basal nerve plexus disruption were also described in patients receiving preserved PGAs. CONCLUSION: PGAs induce several modifications of the OS structures and adnexa; nonetheless, none of them significantly reduces the local safety profile of this class of drugs. Moreover, the OS changes do not affect the IOP lowering efficacy of PGAs. On these bases, local SEs of PGAs should not discourage clinicians in using this class of medications because of their efficacy, the systemic safety profile, and the better adherence.

In Vivo Scanning Laser Confocal Microscopy of Conjunctival Goblet Cells in Medically-controlled Glaucoma.

AIM: The aim of this study was to evaluate the goblet cell density (GCD) of conjunctiva in medically-controlled glaucoma using laser scanning confocal microscopy (LSCM). MATERIALS AND METHODS: Fifty-five glaucomatous patients were enrolled and divided into two groups: Group 1 (27 eyes), controlled with one medication; and group 2 (28 eyes), controlled with two medications. Seventeen patients with dry eye disease (DED) and 17 healthy individuals served as controls. Patients completed the Ocular Surface Disease Index (OSDI) questionnaire and underwent determination of tear film break-up time (BUT), corneal staining, and Schirmer test I. For the GCD assessment, 12 high-quality images were acquired from the upper conjunctival epithelium (superior nasal, superior central, and superior temporal sectors). RESULTS: Overall, GCD was significantly reduced in both glaucoma groups and those with DED compared to healthy controls (p<0.001), with values markedly lower in group 2 compared to group 1 (p<0.05). GCD was not significantly different between those with DED and group 2. A significant negative correlation was found of GCD with OSDI and with BUT (p<0.001; R=-0.795 and R=-0.756, respectively). CONCLUSION: Glaucoma therapy leads to a marked reduction of GCs, especially in the associative regimens. Given the negative correlation with tear film function tests, GCD reduction may play a pivotal role in the pathophysiology of the glaucoma-related disease of the ocular surface.

Three-dimensional Laser Scanning Confocal Analysis of Conjunctival Microcysts in Glaucomatous Patients Before and After Trabeculectomy.

BACKGROUND/AIM: In glaucoma, conjunctival epithelial microcysts (CEM) have been extensively investigated by means of laser scanning confocal microscopy. In the present case series, we examined eight glaucomatous patients undergoing trabeculectomy to obtain a 3-dimensional (3-D) characterization of CEM. MATERIALS AND METHODS: Image acquisition was performed in z-scan automatic volume mode by Heidelberg Retina Tomograph III/Rostock Cornea Module and a series of 40 images of 300×300 µm (384×384 pixels) to a maximum depth of 40 µm were acquired throughout the upper bulbar conjunctiva before (at the site planned for surgery) and eight weeks after trabeculectomy. The 3-D volume tissue reconstruction with maximal size of 300×300×40 µm was obtained. RESULTS: In the enface view, CEM appeared as empty, optically clear, round or oval shaped sub-epithelial structures. The 3-D spatial reconstruction showed microcysts as oval-shaped and optically clear elements, which were close, but clearly separated from the epithelium. CEM were embedded in the extra-cellular spaces and located about 10 µm below the epithelial surface. After trabeculectomy, CEM increased density and area especially along the horizontal axis. CONCLUSION: The 3-D in vivo confocal reconstruction of CEM permits for better clarification of their microscopic anatomy and patho-physiological significance, confirming their involvement in AH flow through the bleb-wall after filtration surgery for glaucoma.

Qualitative and Quantitative Assessment of Vascular Changes in Diabetic Macular Edema after Dexamethasone Implant Using Optical Coherence Tomography Angiography.

The aim of this study was to investigate retinal and choriocapillaris vessel changes in diabetic macular edema (DME) after the intravitreal dexamethasone implant (IDI) using optical coherence tomography angiography (OCTA). Moreover, a comparison between morphological and functional parameters of DME and healthy patients was performed. Twenty-five eyes of 25 type 2 diabetic retinopathy patients complicated by macular edema (DME group) and 25 healthy subjects (control group) were enrolled. Superficial capillary plexus density (SCPD) and deep capillary plexus density (DCPD) in the foveal and parafoveal areas, choricapillary density (CCD) and optic disc vessel density (ODVD) were detected using OCTA at baseline and after 7, 30, 60, 90 and 120 days post injection. Best corrected visual acuity (BCVA), retinal sensitivity, and central retinal thickness (CMT) were also evaluated in both groups of patients. A statistically significant difference between the two groups (DME and controls) was found in terms of functional (MP, p < 0.001 and BCVA, p < 0.001) and morphological (CMT, p < 0.001; SCPD in the parafoveal area, p < 0.001; DCPD in the foveal area, p < 0.05 and parafoveal area, p < 0.001; CCD, p < 0.001) parameters. After the treatment, SCPD and DCPD in the foveal and parafoveal areas did not modify significantly during the follow up.

High-Intensity Focused Ultrasound Circular Cyclocoagulation in Glaucoma: A Step Forward for Cyclodestruction?

The ciliary body ablation is still considered as a last resort treatment to reduce the intraocular pressure (IOP) in uncontrolled glaucoma. Several ablation techniques have been proposed over the years, all presenting a high rate of complications, nonselectivity for the target organ, and unpredictable dose-effect relationship. These drawbacks limited the application of cyclodestructive procedures almost exclusively to refractory glaucoma. High-intensity focused ultrasound (HIFU), proposed in the early 1980s and later abandoned because of the complexity and side effects of the procedure, was recently reconsidered in a new approach to destroy the ciliary body. Ultrasound circular cyclocoagulation (UC3), by using miniaturized transducers embedded in a dedicated circular-shaped device, permits to selectively treat the ciliary body in a one-step, computer-assisted, and non-operator-dependent procedure. UC3 shows a high level of safety along with a predictable and sustained IOP reduction in patients with refractory glaucoma. Because of this, the indication of UC3 was recently extended also to naïve-to-surgery patients, thus reconsidering the role and timing of ciliary body ablation in the surgical management of glaucoma. This article provides a review of the most used cycloablative techniques with particular attention to UC3, summarizing the current knowledge about this procedure and future possible developments.

Optical coherence tomography angiography microvascular findings in macular edema due to central and branch retinal vein occlusions.

The aim of this study was to evaluate retinal and choriocapillaris vessel density using optical coherence tomography angiography (OCTA) in eyes with central retinal vein occlusion (CRVO) and branch retinal vein occlusion (BRVO) complicated by macular edema (ME). Sixty eyes of 60 patients with CRVO or BRVO and ME and 40 healthy subjects underwent measurements of superficial and deep foveal and parafoveal vessel density (FVD, PFVD) and choricapillary density using OCTA at baseline and 60 days after intravitreal dexamethasone implant (IVDEX). FVD and PFVD of the superficial plexus were not significantly lower in CRVO group compared to the controls while in the BRVO group overall PFVD were significantly lower compared to control group (p < 0.001). Overall PFVD of the deep plexus was significantly lower in CRVO and BRVO groups compared to the control group (p < 0.001). FVD and overall PFVD of choriocapillaris were significantly reduced compared to controls in CRVO group (p < 0.001) and PFVD of choriocapillaris was significantly reduced compared to controls in the affected hemi fields in BRVO groups (p < 0.001). OCTA showed vessel density reduction in BRVO and CRVO with main involvement of the deep retinal plexus compared to the superficial retinal plexus due to ischemia that did not recover after intravitreal dexamethasone implant.

Curcuma longa Is Able to Induce Apoptotic Cell Death of Pterygium-Derived Human Keratinocytes.

Pterygium is a relatively common eye disease that can display an aggressive clinical behaviour. To evaluate the in vitro effects of Curcuma longa on human pterygium-derived keratinocytes, specimens of pterygium from 20 patients undergoing pterygium surgical excision were collected. Pterygium explants were put into culture and derived keratinocytes were treated with an alcoholic extract of 1.3% Curcuma longa in 0.001% Benzalkonium Chloride for 3, 6, and 24 h. Cultured cells were examined for CAM5.2 (anti-cytokeratin antibody) and CD140 (anti-fibroblast transmembrane glycoprotein antibody) expression between 3th and 16th passage to assess cell homogeneity. TUNEL technique and Annexin-V/PI staining in flow cytometry were used to detect keratinocyte apoptosis. We showed that Curcuma longa exerts a proapoptotic effect on pterygium-derived keratinocytes already after 3 h treatment. Moreover, after 24 h treatment, Curcuma longa induces a significant increase in TUNEL as well as Annexin-V/PI positive cells in comparison to untreated samples. Our study confirms previous observations highlighting the expression, in pterygium keratinocytes, of nuclear VEGF and gives evidence for the first time to the expression of nuclear and cytoplasmic VEGF-R1. All in all, these findings suggest that Curcuma longa could have some therapeutic potential in the treatment and prevention of human pterygium.

In Vivo Laser Scanning Confocal Microscopy of Human Meibomian Glands in Aging and Ocular Surface Diseases.

Meibomian glands (MGs) play a crucial role in the ocular surface homeostasis by providing lipids to the superficial tear film. Their dysfunction destabilizes the tear film leading to a progressive loss of the ocular surface equilibrium and increasing the risk for dry eye. In fact, nowadays, the meibomian gland dysfunction is one of the leading causes of dry eye. Over the past decades, MGs have been mainly studied by using meibography, which, however, cannot image the glandular structure at a cellular level. The diffusion of the in vivo laser scanning confocal microscopy (LSCM) provided a new approach for the structural assessment of MGs permitting a major step in the noninvasive evaluation of these structures. LSCM is capable of showing MGs modifications during aging and in the most diffuse ocular surface diseases such as dry eye, allergy, and autoimmune conditions and in the drug-induced ocular surface disease. On the other hand, LSCM may help clinicians in monitoring the tissue response to therapy. In this review, we summarized the current knowledge about the role of in vivo LSCM in the assessment of MGs during aging and in the most diffuse ocular surface diseases.

Advance in the pathogenesis and treatment of normal-tension glaucoma.

Normal-tension glaucoma (NTG) is a multifactorial disease where mechanical stresses and vascular alterations to the optic nerve head probably represent the key pathogenic moments. Although intraocular pressure (IOP) plays a crucial role in the retinal ganglion cell loss, the IOP reduction does not necessarily reduces the disease progression. Therefore, several IOP-independent factors such as glutamate toxicity, oxidative stress, autoimmunity, and vascular dysregulation have been considered in the pathogenesis of NTG. Numerous evidences documented an impairment of the ocular blood flow, involved both in the onset and progression of the disease. The IOP reduction remains the main strategy to reduce the damage progression in NTG. Recently, new treatment strategies have been proposed to improve the control of the disease. Neuroprotection is a rapidly expanding area of research, which represents a promising tool. In the present review, we summarize the recent scientific advancements in the pathogenesis and treatment of NTG.