Contrast is the differential luminance between one object and another. Contrast sensitivity (CS) quantifies the ability to detect this difference: estimating contrast threshold provides information about the quality of vision and helps diagnose and monitor eye diseases. High contrast visual acuity assessment is traditionally performed in the eye care practice, whereas the estimate of the discrimination of low contrast targets, an important complementary task for the perception of details, is far less employed. An example is driving when the contrast between vehicles, obstacles, pedestrians, and the background is reduced by fog. Many conditions can selectively degrade CS, while visual acuity remains intact. In addition to spatial CS, “temporal” CS is defined as the ability to discriminate luminance differences in the temporal domain, i.e., to discriminate information that reaches the visual cortex as a function of time. Likewise, temporal sensitivity of the visual system can be investigated in terms of critical fusion frequency (CFF), an indicator of the integrity of the magnocellular system that is responsible for the perception of transient stimulations. As a matter of fact, temporal resolution can be abnormal in neuro-ophthalmological clinical conditions. This paper aims at considering CS and its application to the clinical practice.
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.
Background: Femtosecond laser astigmatic keratotomy (FSAK) and toric intraocular lens (IOL) implantation have been studied individually for comparison to treat astigmatism at cataract surgery. We report a case of surgically induced high corneal astigmatism by laser thermal keratoplasty (LTK) in a patient with cataract who was successfully treated with simultaneous combination of FSAK and toric IOL implantation with femtosecond laser-assisted cataract surgery (FLACS). This is the first report of both procedures combined simultaneously, with or without history of LTK.
Case Description: A 68-year-old male presented with a history of LTK with two enhancements each eye in 2004, with subsequent surgically induced high corneal astigmatism, and with age-related nuclear cataract of both eyes. IOL master demonstrated +7.71 diopters of astigmatism at 163 degree right eye and +3.29 diopters of astigmatism at 4 degree left eye. After extensive discussion of the risks and benefits, the patient agreed to undergo FLACS with FSAK with two 61 degrees of relaxation incisions (RIs) and toric IOL (Alcon SN6AT9) right eye; FLACS with toric IOL (Alcon SN6AT7) alone left eye. At 2-year follow-up, uncorrected visual acuity was 20/30 right eye, 20/25 left eye. His best corrected visual acuity was 20/25 (+0.25 +1.00 axis 21) right eye and 20/20 (plano +0.25 axis 90) left eye; his best corrected near visual acuity was J1+ with add +2.50 diopters right eye and left eye.
Conclusions: Patients with age-related cataract and LTK induced high corneal astigmatism can hardly be sufficiently treated with FSAK or toric IOL alone at the time of cataract surgery. An effective way is to combine large FSAK and toric IOL of the highest cylindrical power of T9, in our case, simultaneously, which can achieve an excellent long term visual outcome.
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: The highly competitive offer of medical training programs and schools, globalization and constant mobility of physicians and medical students (MS), and the commitment to society to deliver competent physicians, demands the definition of performance standards. This would allow to make their performances comparable no matter where they studied or which textbook did they used as reference, to have evaluation mechanisms that guarantee mastery of the integral evaluation of the performance. Assessment has been the key in the teaching-learning process as this obtains a formative and summative element, at different moments, from the extent to which the students have acquired knowledge, skills and attitudes. The progress of the learner must be enhanced with effective feedback on their performance and self-direction of the results obtained in each of the mechanisms established. If, traditionally, this has been considered as the accreditation of compliance with a standard, the evaluation also functions in an integral way as a formative process that identifies advances and deficiencies in the training of residents that allows the definition of actions and strategies for improving the operation of the programs. Different assessment mechanisms are associated with the areas of competence domain, some of the most common tools are: theoretical exams, checklists and rubrics, portfolio, projects and challenges. However, the importance of defining standards which are perceived as fair and designed according to the learning objectives remains a priority to guarantee the credibility of the evaluation agencies and institutions. Some strategies to assure credibility include the involvement of expert and trained evaluators, allowing the process to be carried out with transparency and diligence, and the principles employed should be supported by educational research.
Abstract: Program accreditation is usually a voluntary process based on published standards and performed by a governmental or non-governmental agency of peers. The accreditation process has several components: self-assessment guide completion, site visit and review of program data by the accrediting body. Program accreditation’s primary function is to facilitate self-assessment, provide standards of education and lead to program improvement. It also serves to protect the student’s education and ultimately improve patient care. The International Council of Ophthalmology has developed International Guidelines for accreditation of ophthalmology residency programs and is launching a pilot program to accredit programs on demand.
Abstract: Graduate medical education (GME) has shifted its curricula from process-oriented approach to outcomes-oriented models. Program and faculty evaluation are methods by which educational curricula may adjust the teaching and learning environment to meet the needs and fills the gaps in GME. The measurement of educational outcomes is an essential for assessing teaching effectiveness in a shifting health care environment. In addition to trainee, program, and faculty evaluations, annual program review (APR) and evaluation and navigational changes made by the program education committee are essential to maintain effectiveness of an educational curriculum in a contemporary graduate medical training program.
Abstract: The goal of ophthalmology residency training is to produce competent ophthalmologists. Appropriate assessments must be employed to ensure this goal is met. Valid and reliable workplace-based assessments are designed to assess competence in the many domains required of a good ophthalmologist. These assessments increase standardization and objectivity as compared to simple observational feedback. When used appropriately, workplace based assessments not only provide measures of competence but also facilitate effective formative feedback and enhance learning.
