Phenotypic and functional characterization of aqueous humor derived extracellular vesicles.

Extracellular vesicles (EVs) are double membrane vesicles, abundant in all biological fluids. However, the characterization of EVs in aqueous humor (AH) is still limited. The aim of the present work was to characterize EVs isolated from AH (AH-EVs) in terms of surface markers of cellular origin and functional properties. We obtained AHs from patients with cataract undergoing surgical phacoemulsification and insertion of intraocular lenses (n = 10). Nanoparticle tracking analysis, electron microscopy, super resolution microscopy and bead-based cytofluorimetry were used to characterize EVs from AH. Subsequently, we investigated the effects of AH-EVs on viability, proliferation and wound healing of human immortalized keratinocyte (HaCaT) cells in vitro in comparison with the effect of mesenchymal stromal cell-EVs (MSC-EVs). AH-EVs had a mean size of around 100 nm and expressed the classical tetraspanins (CD9, CD63 and CD81). Super resolution microscopy revealed co-expression of CD9, CD63 and CD81. Moreover, cytofluorimetric analysis highlighted the expression of mesenchymal, stem, epithelial and endothelial markers. In the in vitro wound healing assay on HaCaT cells, AH-EVs induced a significantly faster wound repair, comparable to the effects of MSC-EVs, and promoted HaCaT cell viability and proliferation. We provide evidence, herein, of the possible AH-EV origin from stromal cells, limbal epithelial/stem cells, ciliary epithelium and corneal endothelium. In addition, we showed their in vitro proliferative and regenerative capacities.

Visual symptoms in a patient treated with MEK inhibitors.

PURPOSE: to report an uncommon presentation of Encorafenib-Binimetinib retinal side effects. CASE REPORT: A 56-year-old Caucasian woman, naïve to previous chemotherapies, was started on Encorafenib/Binimetinib for metastatic melanoma. After seven hours from the first 45 mg Binimetinib dose, the patient developed blurry vision with coloured halos. The symptoms were transient and the following day a complete ophthalmological examination revealed the presence of subretinal fluid (SRF) at Optical coherence tomography (OCT). After one week, the patient remained asymptomatic, with no signs of SRF at the follow up reevaluation. However, six weeks later, the symptoms originally experienced with the first drug intake appeared again. This time fundus examination revealed an irregular macular region. At infrared OCT an almond shaped hyporeflective lesion, surrounded by hyperreflectivity, was demonstrated without signs of SRF. Encorafenib/Binimetinib was continued at the same dose and strict monitoring was scheduled, according to the European Medicine's Agency indication to withhold the drug only in presence of symptomatic retinal pigment epithelial detachment. CONCLUSION: Visual symptoms associated with SRF induced by Binimetinib have been described in the literature. In our case, visual symptoms were experienced by the patient at different times, both with and without evidence of SRF. This finding seems to suggest that while Binimetinib-induced SRF is an asymptomatic finding in most cases, with excellent outcome and rapid resolution, visual symptoms could be initially triggered by detectable SRF, yet persist without any further evidence of abnormal fluid accumulation and manifest intermittently.

The Prevalence of Teleophthalmology in the Piedmont Region of Italy: Current Situation and Future Perspectives.

PURPOSE: This cross-sectional study aims to evaluate the actual prevalence of telemedicine, with a particular attention to teleophthalmology programs, in the Piedmont region of Northern Italy and investigate the prospects of the discipline, comparing the situation with the rest of Italy. Information about the current teleophthalmological development is important to assess the state-of-the-art of innovation in medicine in different areas of the world so that there can be a healthy comparison and evaluation of progress and backlog. METHODS: We sent questionnaires to every Local Healthcare Authority and gathered the answers in five distinct categories. Due to the COVID-19 pandemic, we collected information by telephone. We investigated five primary areas: what type of telemedicine services are currently in operation, how they are managed, the presence of any evaluation of patient satisfaction and cost-savings, and the prospects of future teleophthalmology programs to be implemented. RESULTS: Only 2% of the total telemedicine programs are in the field of ophthalmology. The greater parts are in the field of cardiology (15%) and endocrinology (13%). Currently, only one program of teleophthalmology exists in the territory, and at least four more projects are waiting to be approved or funded. Surveys about patient satisfaction were not provided and there was no evidence of cost-saving. CONCLUSIONS: Teleophthalmology in Piedmont is slowly developing, although there is a lack of a unified network for storing and managing patients' data. During the COVID-19 pandemic, telemedicine usage drastically increased, and there is a need to evaluate this trend to understand its place in the future of medicine.

Advantages of Double Running Sutures in Astigmatism After Penetrating Keratoplasty.

Background: The purpose of this prospective study is to evaluate the effects of different suturing techniques in perforating keratoplasty surgery, in order to identify the most effective in reducing post-operative astigmatism. Methods: We analysed data from patients who underwent penetrating keratoplasty for different indications. All interventions were performed by the same surgeon. Patients were subjected to a follow-up of at least 12 months after surgery, during which astigmatism (assessed by keratometry, topography and refraction) best-corrected visual acuity (BCVA) and complications were evaluated. A total of 100 eyes from 100 patients were included and were randomly assigned to five different groups, each one featuring a different suturing technique: interrupted (INT), single running (SRS), double running with two 10-0 sutures (DRS), double running antitorque with two 10-0 sutures (DRSa), double running with both 10-0 and 11-0 sutures (DRS with 11-0). Results: There is a statistically significant difference in astigmatism after surgery between the double running sutures groups and the others with different techniques. However, there is no statistically significant difference between the INT and the SRS group; moreover, there is no statistically significant difference between the different groups with double running sutures (DRS, DRSa, DRS with 11-0). There is no statistically significant difference in BCVA values among the five groups. The wound leak rate was 10% in the INT group, 5.3% in the SRS group and 0% in all groups with double running sutures. Conclusion: In penetrating keratoplasty surgery, the double running suture technique reduces postoperative astigmatism, provides faster visual rehabilitation and features lower complication rates when compared to techniques featuring single running and interrupted sutures. No significant difference in terms of postoperative astigmatism or complication rates was observed among patients receiving double running suture techniques.

Mesenchymal Stem Cell-Derived Extracellular Vesicles Protect Human Corneal Endothelial Cells from Endoplasmic Reticulum Stress-Mediated Apoptosis.

Corneal endothelial dystrophy is a relevant cause of vision loss and corneal transplantation worldwide. In the present study, we analyzed the effect of mesenchymal stem cell (MSC)-derived extracellular vesicles (MSC-EVs) in an in vitro model of corneal dystrophy, characterized by endoplasmic reticulum stress. The effects of MSC-EVs were compared with those of serum-derived EVs, reported to display a pro-angiogenic activity. MSC-EVs were able to induce a significant down-regulation of the large majority of endoplasmic reticulum stress-related genes in human corneal endothelial cells after exposure to serum deprivation and tunicamycin. In parallel, they upregulated the Akt pathway and limited caspase-3 activation and apoptosis. At variance, the effect of the serum EVs was mainly limited to Akt phosphorylation, with minimal or absent effects on endoplasmic reticulum stress modulation and apoptosis prevention. The effects of MSC-EVs were correlated to the transfer of numerous endoplasmic reticulum (ER)-stress targeting miRNAs to corneal endothelial cells. These data suggest a potential therapeutic effect of MSC-EVs for corneal endothelial endoplasmic reticulum stress, a major player in corneal endothelial dystrophy.

A Retrospective Comparison of Trabeculectomy, Baerveldt Glaucoma Implant, and Microinvasive Glaucoma Surgeries in a Three-Year Follow-Up.

Purpose: This retrospective study aimed to evaluate the safety and efficacy of MIGS (Xen® and Cypass®) compared to trabeculectomy and Baerveldt® implants.Patients and Methods: This single-center study included patients from the Ophthalmic Hospital of Turin between January 2015 and 2018.Efficacy was assessed based on the intraocular pressure and the number of medications necessary to control IOP at 1, 3, 6, 12, 24, and 36 months and the potential complications. Complete surgical success was defined as IOP ≤ 21 mmHg, with no medication or additional glaucoma surgery. Qualified success was defined as IOP ≤ 21 mmHg with the reintroduction of topical medications. Our third measure of success was a delta IOP reduction greater than 20% compared to baseline.Results: The delta IOP compared to the baseline was significant at every instance, except in the Xen® implant group. The average IOP distribution at different time points was significant, except at 1 and 12 months. The delta of the medication number compared to the baseline was significant at every instant. All three methods of success were analyzed using a Kaplan-Meier survival curve that identified a significant difference on the success rates of Xen®-trabeculectomy, Xen®-Baerveldt®, and Cypass®-Baerveldt®.Conclusion: MIGS can reduce the number of medication classes, thus increasing patient compliance and reducing topical ocular toxicity and general costs. Trabeculectomy remains the most effective option but still presents a percentage of failures that might increase during follow-up.

Long-Term Effects of Iron Chelating Agents on Ocular Function in Patients with Thalassemia Major.

BACKGROUND: The aim of this study is to evaluate eye structures and function in patients receiving iron chelating therapy and to assess whether a correlation exists between the onset of ocular alterations and the intake of iron chelating drugs. METHODS: A prospective cohort study was performed. Eighty-eight patients, composed of children and adults with thalassemia major (TM) who are taking or had taken iron chelating drugs (deferoxamine, deferiprone or deferasirox), have been initially enrolled in the study. The final sample featured 80 patients, including 18 children and 62 adults. These subjects received an eye examination to evaluate intraocular pressure (IOP), best corrected visual acuity (BCVA), the presence of refractive defects, cornea, anterior chamber, lens, fundus oculi, visual field and mean retinal nerve fiber layer (RNFL) thickness. Logistic regression model analysis was performed in order to assess any correlation. In addition, a literature search regarding the relation between iron chelating drugs and ocular adverse events was carried out to compare the results obtained with the evidence in the literature. RESULTS: Logistic regression did not report a significant correlation between the intake of iron chelating drugs and the onset of anterior ocular segment alterations, lens opacities, retinal diseases, optical neuropathies, astigmatism, visual field and RNFL thickness defects. Logistic regression returned a statistically significant correlation between myopia and iron chelation therapy (p-value 0.04; OR 1.05) and also between presbyopia and total duration of therapy with deferoxamine (p-value 0.03; OR 1.21). Although intraocular pressure levels remained within the normal range, a significant correlation with the length of deferoxamine therapy has been found (p-value 0.002; association coefficient -0.12). A negative correlation between deferiprone and presbyopia has also been observed. CONCLUSION: Iron chelation therapy is not associated with severe visual function alterations. Limitation of deferoxamine treatment can help prevent ocular complications. Deferiprone and/or deferasirox may be preferable, especially in patients over age 40 years.

Diagnostic imaging versus surgical procedure: intra- and postoperative OCT evaluation of sutureless scleral-fixated intraocular lens implantation and possible related complications.

Because the popularity of corneal refractive surgery has been increasing throughout the last 25 years, many authors have thought to apply optical coherence tomography (OCT) to the anterior segment (AS-OCT); by revising the instrumentation needed and slightly improve the technique, it has become an element of vital importance in order to ensure a complete and exhaustive pre- and postsurgical evaluation. Many applications of OCT have been recently developed-mostly in cataract surgery due to the increasing numbers-such as chamber biometry, which is used in a preoperative stage to determine the details of IOL implantation, and lens evaluation. The aim of this review is to assess the applications of anterior segment OCT in dislocated IOL and/or capsular bag exchange surgery with scleral sutureless fixated intraocular lens and monitoring of possible postoperative complications.

Effect of Stem Cell-Derived Extracellular Vesicles on Damaged Human Corneal Endothelial Cells.

PURPOSE: Human corneal endothelial cells (HCECs) are essential to visual function; however, since they have limited proliferative capacity in vivo, they are prone to corneal endothelial dysfunction. At present, the only treatment is a corneal transplantation from donor cadavers. Also, due to a global shortage of donor corneas, it is important to find alternative strategies. Recent studies highlight that stem cell-derived extracellular vesicles (EVs) play a relevant role in stem cell-induced regeneration by reprogramming injured cells and inducing proregenerative pathways. The aim of this work is to evaluate whether EVs derived from mesenchymal stem cells (MSC-EVs) are able to promote regeneration of damaged HCECs. METHODS: We isolated HCECs from discarded corneas in patients undergoing corneal transplantation or enucleation (N = 23 patients). Bone marrow mesenchymal stem cells (MSCs) were obtained from Lonza, cultured, and characterized. MSC-EVs were obtained from supernatants of MSCs. In order to establish a valid in vitro damage model to test the regenerative potential of EVs on HCECs, we evaluated the proliferation rate and the apoptosis after exposing the cells to serum-deprived medium at different concentrations for 24 hours. We then evaluated the HCEC migration through a wound healing assay. RESULTS: In the selected serum deprivation damage conditions, the treatment with different doses of MSC-EVs resulted in a significantly higher proliferation rate of HCECs at all the tested concentrations of EVs (5-20 × 103 MSC-EV/cell). MSC-EVs/cell induced a significant decrease in number of total apoptotic cells after 24 hours of serum deprivation. Finally, the wound healing assay showed a significantly faster repair of the wound after HCEC treatment with MSC-EVs. CONCLUSIONS: Results highlight the already well-known proregenerative potential of MSC-EVs in a totally new biological model, the endothelium of the cornea. MSC-EVs, indeed, induced proliferation and survival of HCECs, promoting the migration of HCECs in vitro.

Choroidal vascularization and adrenergic innervation qualitative findings obtained with induced fluorescence preparations and optical coherence tomography angiography: possible correlations and perspectives.

BACKGROUND: Recent advances in optical coherence tomography (OCT) technology allow a more accurate choroidal visualization. The aim of this study is to provide histochemical analysis with induced fluorescence images of the choroidal stromal, vascular and nerve network, highlighting possible correspondences with OCT and OCT angiography (OCT-A) analysis. METHODS: The material examined with a histochemical process of induced fluorescence through condensation of biologically active monoamines with glyoxylic acid was obtained from 6 eyes enucleated for malignant melanoma and ciliary body neoplasia. The resulting images have been qualitatively compared with OCT and OCT-A choroidal images obtained from 10 volunteers, in order to identify possible relationships. Choriocapillary segmentation was performed automatically through the embedded analysis software, while segmentation of Sattler's and Haller's layers was performed through a manual method. RESULTS: Histochemical analysis provided accurate visualization of choroidal adrenergic innervation across all layers and its relationships with blood vessels and melanocytes. The above structures were not visualized at OCT and OCT-A which provided good visualization of blood vessels in Sattler's and Haller's layers as well-delimited hyporeflective areas. Decorrelation signal was not detected in OCT-A analysis due to low blood flow velocity in external choroidal layers. CONCLUSIONS: The choroid is an extremely dynamic structure which deserves to be analyzed in vivo since it is involved in the pathogenesis of several ocular conditions. Direct evaluation of the activity of choroidal nerves and melanocytes is still not possible with OCT and OCT-A, even if they are capable of providing a satisfactory representation of choroidal vascularization.

CMV retinitis in a stem cell transplant recipient treated with foscarnet intravitreal injection and CMV specific immunoglobulins.

Cytomegalovirus (CMV) retinitis (CMVR) has been reported rarely in patients undergoing allogeneic hematopoietic stem cell transplantation (HSCT). In addition, little is known about strategies for ophthalmic surveillance and adequate antiviral treatment of CMVR. A case of CMVR in an allogeneic HSCT recipient is described, including clinical signs and therapy. An adult patient received HSCT from a matched unrelated donor for treatment of a Burkitt lymphoma. Donor and recipients were both CMV positive. Starting on day +40, the patient presented multiple CMV reactivation, treated with valganciclovir, foscarnet and a combination of both. On day +160, the patient started complaining of conjunctival hyperaemia and a decrease in visual acuity. Fundoscopy revealed retinal lesions consistent with CMVR, although whole blood CMV DNAemia was negative. Aqueous humor biopsy showed the presence of CMV infection (CMV DNA 230400 UI/ml). CMVR was treated with foscarnet (180 mg i.v. and 1.2 mg intravitreal injection) combined with anti CMV immunoglobulin at 0.5 ml/kg every 2 weeks. After 4 weeks of systemic therapy, 20 weekly doses of intravitreal foscarnet and six cycles of immunoglobulins, a significant improvement of visual acuity was observed. The treatment was well tolerated with no side effect. In conclusion, our case suggests that systemic and local antiviral treatment combined with CMV-specific-IVIG, may reduce CMV load in the eye of patients with CMVR, leading to a consistent improvement of visual acuity. Systematic ophthalmologic examination should be recommended in HSCT recipients with multiple CMV reactivations and high peak CMV DNA levels.

Effect of Mesenchymal Stem Cell-Derived Exosomes on Retinal Injury: A Review of Current Findings.

In recent years, various studies have followed in the literature on the therapeutic effects of mesenchymal stem cells (MSC) on damage in retinal cells. The evidence that MSCs exert their regenerative and damage reduction effect in a paracrine way, through the release of soluble factors and exosomes, is now consolidated. Exosomes are microvesicles formed by a double layer of phospholipid membrane and carry proteins and RNA, through which they play a therapeutic role on target cells. Scientific research has recently focused on the use of exosomes derived from MSC in various models of retinal damage in vitro and in vivo as they, compared to MSCs, have similar functions and at the same time have different advantages such as greater stability and handling, a lower chance of immunological rejection and no risk of malignant transformation. The purpose of this review is to summarize current knowledge on the therapeutic use of exosomes derived from MSCs in retinal damage and to stimulate new clinical perspectives regarding their use.

Ocular Complications After Radiation Therapy: An Observational Study.

AIM OF THE STUDY: The study aims to quantify the incidence of ocular complications in patients irradiated on the head and neck area in our medical center, stratified by type of neoplasm and radiation dose received. MATERIALS AND METHODS: From an existing database of patients radio-treated in our center, we selected 25 patients irradiated in the 2011-2018 period. The patients had been treated for orbital lymphoma, nasopharyngeal carcinoma and cranial base meningioma. The selected patients received an ophthalmologic evaluation which included a complete ophthalmological and orthoptic assessment. RESULTS: Our results showed a significantly higher incidence of DES (dry eye syndrome) and corneal complications for eyes receiving a Dmax higher than 40 Gy, as well as for cataract incidence in eyes that had received a Dmax to the lens higher than 5 Gy. We found an overall thinning of the RNFL (retinal nerve fiber layer) in eyes that had received a Dmax higher than 50 Gy, as well as a greater MD (mean deviation) from normal visual field values. CONCLUSION: In conclusion, we can say that the study confirms the presence of a correlation between the received radiation dose and the onset of eye complications, despite the small sample.

Big Bag IOL Implantation with Scleral Fixation Technique in IOL/Crystalline Lens Subluxation/Luxation Cases and High Myopia.

PURPOSE: The aim of this study is to report our experience in the surgical management of over 180° luxation/subluxation of the intraocular lens (IOL). Special cases are high myopic eyes, whose tissues are constitutionally more fragile, and consequently, surgery is more dangerous. PATIENTS AND METHODS: The authors propose the use of the Big Bag, three loops, IOL (Zeiss), to be implanted with the scleral fixation technique, with a double-armed needle. This technique seems to improve IOL stability and visual outcome of these patients. RESULTS: Big Bag IOL implantation with the scleral fixation technique in eyes with subluxation (over 180°) of the cataractous lens, high myopia and subluxation/dislocation of the IOL seems to suggest a possible and optimal management, with good long-term results and it is well tolerated by the patient. CONCLUSION: This specific ocular surgical technique can be used/standardized in all surgical "converted" complicated cases and especially in high myopic eyes.

Pediatric Keratoplasty: The Success of a Tailor-Made Surgical Management.

A Romanian 5-month-old girl was referred to our hospital after being diagnosed with congenital corneal opacities. She was sent in order to undergo penetrating keratoplasty (PKP) surgery on her left eye. The patient presented a natural tendency to esotropia. We took into account two different surgical techniques: PKP and lamellar keratoplasty. The latter was technically impossible to carry out because of the full-thickness corneal opacity. We conducted several tests to accurately obtain the patient's preoperative parameters and specifically decide the details of the surgical technique to be applied. For each step of the surgical procedure we carefully compared the individual results in the literature in order to ensure a stable and lasting result. In addition to this, we used an innovative suture technique: nylon thread, interrupted suture, alternating 11-0/10-0 threads. Six months after the operation, the functional result obtained was 4-5/10, with recovery of the fixation. Pediatric PKP, therefore, cannot follow a surgical standard, but requires careful case-by-case evaluation from the pre- to the postoperative phase, with the aim of maximizing stable visual acuity.

Perspectives of Autologous Mesenchymal Stem-Cell Transplantation in Macular Hole Surgery: A Review of Current Findings.

The main treatment available for idiopathic macular holes is represented by pars plana vitrectomy with internal limiting membrane peeling. However, late-stage macular holes are affected by a higher risk of surgical failure. Although adjuvant techniques can be employed, a satisfactory functional recovery is difficult to achieve in refractory macular holes. Given their neuroprotective and antiapoptotic properties, mesenchymal stem cells (MSCs) may represent an appealing approach to treat these extreme cases. The purpose of this review is to highlight the findings regarding healing mechanisms exerted by mesenchymal stem cells and preliminary application in cases of refractory macular holes. When compared with MSCs, MSC-derived exosomes may represent a feasible alternative, given their reduced risk of undesired proliferation and easiness of use.

How to minimize pterygium recurrence rates: clinical perspectives.

The main treatment for pterygium is surgical removal. However, pterygium surgery is concerned with high rates of postoperative recurrence. Predicting factors of recurrence are not fully understood, yet, but they probably depend on a multitude of patient-related, clinical, and/or surgical factors. Several adjuvant treatments have been proposed to reduce postoperative pterygium recurrence, including different antimetabolites, antiangiogenetic factors, and radiation therapy. The purpose of this review is to collect the current evidence regarding application and limits of different therapeutic approaches for preventing postoperative recurrence of pterygium, giving insights and perspectives for better management of this disease. In the light of the current evidence, pterygium surgery cannot disregard wound coverage with conjunctival autografting or rotational flap combined with adjuvant treatments. The rotational flap technique is associated with shorter surgical time rates and prevents graft displacement and necrosis, given its vascular pedicle. Amniotic membrane may still be reserved in case of great conjunctival defects or insufficient conjunctiva. Repeated subconjunctival antivascular endothelial growth factor injections can be considered as an effective and safe adjuvant treatment. Moreover, management of postoperative pain is crucial. Innovative treatment strategies will probably target different molecular pathways, considering recent findings regarding pterygium pathogenesis, to improve better understanding and develop universally shared guidelines. Great importance shall be dedicated to the identification of novel molecular biomarkers and favoring factors of recurrence, in order to achieve a customized surgical treatment for each patient and obtain maximal reduction of postoperative recurrence.

Best Prophylactic Strategy in Groups at Risk of Intraoperative Floppy Iris Syndrome Development: Comparison Between Atropine Instillation and Adrenaline Intracameral Injection.

BACKGROUND: Intraoperative Floppy Iris Syndrome (IFIS) is an important cause of surgical complications and iris defects in patients undergoing phacoemulsification that were treated with selective subtype α1A receptor antagonists for a long period of time. To date, no definitive preventive strategy has emerged, yet. The need of prophylaxis is dictated by the high prevalence of males affected by benign prostatic hyperplasia undergoing cataract surgery. OBJECTIVE: To identify the best prophylactic strategy in groups at risk of IFIS development by comparing two mydriatic treatments in course of phacoemulsification surgery. METHODS: 81 eyes of 81 patients in treatment with Tamsulosin were enrolled in the study. 43 eyes were treated with atropine sulfate 1% while 38 eyes received an injection of mydriatic solution containing epinephrine in the anterior chamber. All phacoemulsifications were videotaped in order to assess the occurrence of IFIS and the severity of the syndrome. RESULTS: The treatment group showed a statistically significant reduction (p = 0.0115) of floppy iris syndrome incidence, from 86.05% (37/43) of the atropine group to 60.53% (23/38). The analysis showed a reduction of IFIS mild form only, whereas the incidence of severe forms remained unchanged. CONCLUSIONS: We believe that IFIS may arise through two different mechanisms: pharmacological antagonism and anatomical modifications. Patients suffering from mild forms of the disease showed a statistically significant reduction of IFIS incidence after intraoperative prophylaxis due to epinephrine's ability to displace Tamsulosin, resulting in the increase of iris tone when the disease is caused mainly by receptorial antagonism. On the contrary, prophylaxis does not deliver any valuable result in case of severe forms where the anatomical variations play a major role.

Gonadal Hormones and Retinal Disorders: A Review.

AIM: Gonadal hormones are essential for reproductive function, but can act on neural and other organ systems, and are probably the cause of the large majority of known sex differences in function and disease. The aim of this review is to provide evidence for this hypothesis in relation to eye disorders and to retinopathies in particular. METHODS: Epidemiological studies and research articles were reviewed. RESULTS: Analysis of the biological basis for a relationship between eye diseases and hormones showed that estrogen, androgen, and progesterone receptors are present throughout the eye and that these steroids are locally produced in ocular tissues. Sex hormones can have a neuroprotective action on the retina and modulate ocular blood flow. There are differences between the male and the female retina; moreover, sex hormones can influence the development (or not) of certain disorders. For example, exposure to endogenous estrogens, depending on age at menarche and menopause and number of pregnancies, and exposure to exogenous estrogens, as in hormone replacement therapy and use of oral contraceptives, appear to protect against age-related macular degeneration (both drusenoid and neurovascular types), whereas exogenous testosterone therapy is a risk factor for central serous chorioretinopathy. Macular hole is more common among women than men, particularly in postmenopausal women probably owing to the sudden drop in estrogen production in later middle age. Progestin therapy appears to ameliorate the course of retinitis pigmentosa. Diabetic retinopathy, a complication of diabetes, may be more common among men than women. CONCLUSION: We observed a correlation between many retinopathies and sex, probably as a result of the protective effect some gonadal hormones may exert against the development of certain disorders. This may have ramifications for the use of hormone therapy in the treatment of eye disease and of retinal disorders in particular.

State of the art of robotic surgery related to vision: brain and eye applications of newly available devices.

BACKGROUND: Robot-assisted surgery has revolutionized many surgical subspecialties, mainly where procedures have to be performed in confined, difficult to visualize spaces. Despite advances in general surgery and neurosurgery, in vivo application of robotics to ocular surgery is still in its infancy, owing to the particular complexities of microsurgery. The use of robotic assistance and feedback guidance on surgical maneuvers could improve the technical performance of expert surgeons during the initial phase of the learning curve. EVIDENCE ACQUISITION: We analyzed the advantages and disadvantages of surgical robots, as well as the present applications and future outlook of robotics in neurosurgery in brain areas related to vision and ophthalmology. DISCUSSION: Limitations to robotic assistance remain, that need to be overcome before it can be more widely applied in ocular surgery. CONCLUSION: There is heightened interest in studies documenting computerized systems that filter out hand tremor and optimize speed of movement, control of force, and direction and range of movement. Further research is still needed to validate robot-assisted procedures.