Although amniotic membrane transplantation (AMT) has long been used as an essential surgical technique for ocular surface reconstruction, its role continues to evolve and expand. In the management of numerous ocular surface disorders, ranging from inflammatory to infectious, traumatic to neoplastic, the ability to perform AMT is a valuable addition to the skillset of any ophthalmologist. The purpose of this paper is to provide ophthalmologists with an updated, evidence-based review of the clinical indications for AMT in corneal and conjunctival reconstruction, reviewing its common and even experimental applications known to date. The methods of amniotic membrane preservation, the available commercial amniotic membrane products to date, and future directions for amniotic membrane use, including amniotic membrane extract eye drops (AMEED), are also discussed. It is paramount for ophthalmologists to stay up-to-date on the applications of AMT so as to effectively incorporate this versatile treatment modality into their practice,both in the operating room and in the clinic. By familiarizing the general ophthalmologist with its diverse applications, we hope to motivate general ophthalmologists to incorporate the use of AMT into their clinical practice, or provide guidance on how to recognize when referral to a corneal specialist for amniotic membrane application is prudent.

Background: A variety of experimental animal models are used in basic ophthalmological research to elucidate physiological mechanisms of vision and disease pathogenesis. The choice of animal model is based on the measurability of specific parameters or structures, the applicability of clinical measurement technologies, and the similarity to human eye function. Studies of eye pathology usually compare optical parameters between a healthy and altered state, so accurate baseline assessments are critical, but few reports have comprehensively examined the normal anatomical structures and physiological functions in these models.

Methods: Three cynomolgus monkeys, six New Zealand rabbits, ten Sprague Dawley (SD) rats, and BALB/c mice were examined by fundus photography (FP), fundus fluorescein angiography (FFA), and optical coherence tomography (OCT).

Results: Most retinal structures of cynomolgus monkey were anatomically similar to the corresponding human structures as revealed by FP, FFA, and OCT. New Zealand rabbits have large eyeballs, but they have large optic disc and myelinated retinal nerve fibers in their retinas, and the growth pattern of retinal vessels were also different to the human retinas. Unlike monkeys and rabbits, the retinal vessels of SD rats and BALB/c mice were widely distributed and clear. The OCT performance of them were similar with human beings except the macular.

Conclusions: Monkey is a good model to study changes in retinal structure associated with fundus disease, rabbits are not suitable for studies on retinal vessel diseases and optic nerve diseases, and rats and mice are good models for retinal vascular diseases. These measures will help guide the choice of model and measurement technology and reduce the number of experimental animals required.

Background: Benign essential blepharospasm (BEB), aberrant facial nerve degeneration and hemifacial spasm (HFS) are all examples dystonia which, though not life-threatening, can have a significant impact on patient quality of life. The need for reliable self-rating surveys to monitor functional disability is fundamental. The Blepharospasm Disability Index (BSDI) is already a widely utilised and validated self-rating score for blepharospasm whilst the functional disability score (FDS) requires further validation. The principle aim of this study is to repeat validation of the FDS against the BSDI, which has been validated by several groups since its original description but only in patients with BEB.

Methods: A randomised blinded prospective cohort study was conducted at a single unit on 38 patients with BEB, aberrant facial nerve degeneration and HFS. Patients were blinded to complete the FDS followed by the BSDI or the BSDI followed by the FDS with a 30-minute interval.

Results: Both the FDS and BSDI were found to be reliable with high internal consistency and test-retest reliability. Both scales were also found to be moderately correlated with the Jankovic disease severity score.

Conclusions: This study is the first to use the FDS as a rating scale in patients with HFS and aberrant facial nerve degeneration. It is also the first study to formally validate the FDS as an acceptable rating scale for patients with dystonia and in particular it provides validation for its use in patients with HFS and aberrant facial nerve degeneration.

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.

Conjunctival flaps have previously proven to be effective in preserving the globe for individuals with severe ocular surface disease. Infectious keratitis, neurotrophic keratitis, nontraumatic corneal melts, descemetoceles, perforations, and corneal burns are all indications for this procedure. The flaps promote nutrition, metabolism, structure, and vascularity, as well as reduce pain, irritation, inflammation, and infection. Furthermore, patients avoid the emotional and psychological repercussions of enucleation or evisceration, while requiring fewer postoperative medications and office visits. Currently, fewer flaps are performed due to the emergence of additional therapeutic techniques, such as serum tears, bandage lenses, corneal grafting, Oxervate, amniotic membrane, and umbilical cord grafting. However, despite newer conservative medical methods, conjunctival flaps have been demonstrated to be useful and advantageous. Moreover, future technologies and approaches for globe preservation and sight restoration after prior conjunctival flaps are anticipated. Herein, we review the history, advantages, and disadvantages of various surgical techniques: Gundersen’s bipedicle flap, partial limbal advancement flap, selective pedunculated conjunctival flap with or without Tenon’s capsule, and Mekonnen’s modified inferior palpebral-bulbar conjunctival flap. The surgical pearls and recommendations offered by the innovators are also reviewed, including restrictions and potential complications. Procedures for visual rehabilitation in selective cases after conjunctival flap are reviewed as well.

Background: To settle the fundamentals of a numerical procedure that relates retinal ganglion-cell density and threshold sensitivity in the visual field. The sensitivity of a generated retina and visual pathways to virtual stimuli are simulated, and the conditions required to reproduce glaucoma-type defects both in the optic-nerve head (ONH) and visual fields are explored.

Methods: A definition of selected structural elements of the optic pathways is a requisite to a translation of clinical knowledge to computer programs for visual field exploration. The program is able to generate a database of normalized visual fields. The relationship between the number of extant receptive fields and threshold sensitivity is plotted for background sensitivity and corresponding automated perimetry. A solution in two planes to the 3D distribution of axons in the ONH is proposed. Visual fields with induced damage in the optic disc are comparable in pattern and quantity to glaucomatous records.

Results: The two-level simulation of the ONH facilitates the analysis of optic-cup/retinal defects. We can generate the virtual optic pathways tailored to the age and morphology of the patient’s eye, and it is possible to reproduce glaucomatous damage by “reverse engineering” engineering. The virtual cortical model renders a quantitative relationship between visual defect and neural damage.

Conclusions: A two-level computing of the retina/optic nerve facilitates the analysis of neuroretinal defects and can be incorporated to automatic perimeters to facilitate visual field analysis.

Abstract: Despite appropriate management of the systemic disease, patients with diabetes may develop severe forms of diabetic retinopathy that require surgery. Non-clearing vitreous haemorrhage (VH), traction retinal detachment involving the macula, combined traction and rhegmatogenous retinal detachment, progressive fibrovascular proliferation (PFP) and rubeosis with acute VH represent the main indications for surgery. Vitrectomy techniques and surgical tools have developed dramatically in the last decade in order to help the surgeon succeed in these challenging cases.

Abstract: Diabetic retinopathy (DR) is a leading cause of visual loss worldwide. Disease severity is graded from mild non-proliferative DR to proliferative DR. Optical coherence tomography angiography (OCTA) has become widely accepted as a useful noninvasive technique that provides detailed imaging of the ocular vessels. It is also becoming an increasingly essential tool for both qualitative and quantitative assessment of DR, especially with the advent of wider imaging capabilities. Various angiographic features of DR, such as microaneurysms, intraretinal microvascular abnormalities, neovascularization, and nonperfusion have been comprehensively studied and described using OCTA. Different quantitative OCTA metrics have been introduced, such as vessel density, foveal avascular zone (FAZ) area, and area of nonperfusion. Current research has been focusing on the application of quantitative OCTA for the diagnosis of DR and treatment monitoring. The primary purpose of this article is to review the use of OCTA, including its challenges, in the diagnosis and management of DR.