Perception is the ability to see, hear, or become aware of external stimuli through the senses. Visual stimuli are electromagnetic waves that interact with the eye and elicit a sensation. Sensations, indeed, imply the detection, resolution, and recognition of objects and images, and their accuracy depends on the integrity of the visual system. In clinical practice, evaluating the integrity of the visual system relies greatly on the assessment of visual acuity, that is to say on the capacity to identify a signal. Visual acuity, indeed, is of utmost importance for diagnosing and monitoring ophthalmological diseases. Visual acuity is a function that detects the presence of a stimulation (a signal) and resolves its detail(s). This is the case of a symbol like “E”: the stimulus is detected, then it is resolved as three horizontal bars and a vertical bar. In fact, within the clinical setting visual acuity is usually measured with alphanumeric symbols and is a three-step process that involves not only detection and resolution, but, due to the semantic content of letters and numbers, their recognition. Along with subjective (psychophysical) procedures, objective methods that do not require the active participation of the observer have been proposed to estimate visual acuity in non-collaborating subjects, malingerers, or toddlers. This paper aims to explain the psychophysical rationale underlying the measurement of visual acuity and revise the most common procedures used for its assessment.
Abstract: To report a palliative and alternative surgical procedure, allogeneic sclera graft combined with autologous conjunctival flap (ASGACF), employing to repair the large emergent corneal perforation. The detail protocol of the surgical procedure was characterized and four representative cases were reviewed. An allogeneic sclera graft and recipient bed were prepared as the traditional penetrating keratoplasty (PK). And then sutured the sclera graft to the bed with 10-0 nylon suture and covered with a pedicled autologous conjunctival flap in half size. In the follow-up, the ASGACF repaired all of the corneal perforations and restored the integral walls of eyeballs, in spite of one who underwent a second surgery. This surgical procedure provided a palliative method to repair the large emergent corneal perforation while there is the lack of a corneal graft.
Background: To assess the safety and efficacy of supracapsular implantation with optic capture of the posterior chamber intraocular lens in Chinese children with aphakic after traumatic cataract.
Methods: It was a retrospective case series study. Fifteen cases (15 eyes) Chinese children received supracapsular implantation with optic capture of the posterior chamber intraocular lens. Pre- and post-operative visual acuities were recorded. Intra- and post-operative complications were observed. The follow-up period ranged from 7 to 43 (28.7±7.2) months.
Results: Implantation of optic capture of the posterior chamber intraocular lens was successfully performed in 15 eyes. The best corrected visual acuity (BCVA) ranged from 0.3 to 1.0 (0.61±0.19). No optic axis opaque was found in 15 eyes with optic capture. The major complications of optic capture were iris posterior synechia and intraocular lens (IOL) precipitates. Intraocular dislocation was found in one case three weeks after the operation.
Conclusions: Supracapsular implantation with optic capture of the posterior chamber intraocular lens is safe and effective for the treatment of traumatic cataract in Chinese children.
Abstract: Diabetic retinopathy (DR) remains a leading cause of irreversible vision loss in adult populations around the globe. Despite growing evidence of the effectiveness of routine assessments and early intervention, DR screening strategies are not widely implemented largely due to an inadequate availability of resources to cope with the growing burden of diabetes. Advances in technology in the field of DR screening are clearly warranted and the recent emergence of deep learning-based artificial intelligence (AI) grading of retinal pathology offers significant potential benefits including an increased efficiency, accessibility and affordability of screening programmes.
Abstract: Four challenging and unusual retinal cases: (I) 11-year follow-up for retinal hemangioblastoma with von Hippel-Lindau (VHL) disease; (II) treatment for central serous chorioretinopathy (CSC)—observation, half does photodynamic therapy (PDT) or micropulse laser photocoagulation; (III) diagnosis and treatment for a child with optic nerve defect; (IV) the optional treatment for retinal detachment (RD) with iridolenticular choroidal coloboma, were presented and discussed by three international retinal specialists at a retinal clinical round in Fundus Diseases Center of Zhongshan Ophthalmic Center (ZOC). The discussion helps us a better understanding of the pathogenesis and managements of these four retinal diseases and their association with systemic conditions.
Abstract: The disease burden of diabetic retinopathy (DR) is tremendous around the world. While DR is correlated with hemoglobin A1c (HbA1c) and duration of diabetes, genetic differences likely account for variation in susceptibility to DR. DR is a polygenic disorder with demonstrated heritability. However, linkage and admixture analyses, candidate gene association studies, and genome-wide association studies (GWAS) have not identified many loci for DR that can be consistently replicated. Larger, collaborative, multi-ethnic GWAS are needed to identify common variants with small effects. Rigorous defining of controls groups as patients with a long duration of diabetes without DR, and case groups as patients with severe DR will also aid in finding genes associated with DR. Replication in independent cohorts will be key to establishing associated loci for DR. Investigations of mitochondrial DNA and epigenetics in DR are ongoing. Whole exome sequencing presents new opportunities to identify rare variants that might be implicated in DR development. Continued research in the genetic epidemiology of DR is needed, with the potential to elucidate pathogenesis and treatment of an important disease.
Abstract: Retinopathy of prematurity (ROP) is a proliferative disorder of the developing retina in premature and low birth weight infants. Recently, the role of vascular endothelial growth factor (VEGF) in the pathophysiology of ROP has been well studied and anti-VEGF drugs have been used in phase 2 to treat ROP patients in many ways. At first, ophthalmologists began to give intravitreal bevacizumab (IVB) or ranibizumab off-label to treat ROP as a salvage treatment after failure in laser photocoagulation or in combination with laser as an adjuvant treatment for patients had media opacity or rigid pupil. Now anti-VEGF drugs are also used as monotherapy in type I ROP or perioperative use in stage 4/5 ROP. Questions remain regarding long-term safety, dose, timing, visual outcomes and long-term effects, including systemically.
Abstract: Training qualified ophthalmic professional is crucial for any eye care system worldwide. Education of modern western Ophthalmology in China started late but develops rapidly. This review focused on ophthalmic education in China and US, describing details of the programs and analyzing the differences. This summary may provide useful information for practitioners of medical education from both countries and help improve the present training designs.
Abstract: Primary vitreoretinal lymphoma (PVRL), as a subset of primary central nervous system lymphoma (PCNSL), is a rare and fatal ocular malignancy. Most PVRL masquerades as chronic posterior uveitis, which makes the clinical diagnosis challenging. Vitreous cells, subretinal lesions and imaging techniques are essential for clinical diagnosis. Importantly, cytopathology/histopathology identification of malignant cells is the gold standard for the diagnosis of PVRL. In addition, molecular detection of immunoglobulin heavy chain (IgH) or T cell receptor (TCR) gene rearrangements, immunophenotyping for cell markers, and cytokine analysis of interleukine-10 elevation are often used as adjunct procedures. Current management of PVRL involves local radiation, intravitreal chemotherapy (methotrexate and rituximab), with or without systemic chemotherapy depending on the involvement of non-ocular tissues. In cases with concomitant PCNSL, systemic high-dose methotrexate/rituximab based therapy in conjunction with local therapy, whole brain radiotherapy and/or autologous stem cell transplantation is considered. Although PVRL normally responds well to initial treatment, high rates of relapse and CNS involvement usually lead to poor prognosis and limited survival. A professional team of medical experts in ophthalmologists, ocular pathologists, neuro-oncologists and hemato-oncologists is essential for optimizing patient management.
