The pupillary light reflex (PLR) adapts the amount of light reaching the retina, protecting it and improving image formation. Two PLR mechanisms have been described in vertebrates. First, the pretectum receives retinal inputs and projects to the Edinger-Westphal nucleus (EWN), which targets the ciliary ganglion through the oculomotor nerve (nIII). Postganglionic fibers enter the eye-globe, traveling to the iris sphincter muscle. Additionally, some vertebrates exhibit an iris-intrinsic PLR mechanism mediated by sphincter muscle cells that express melanopsin inducing muscle contraction. Given the high degree of conservation of the lamprey visual system, we investigated the mechanisms underlying the PLR to shed light onto their evolutionary origins. Recently, a PLR mediated by melanopsin was demonstrated in lampreys, suggested to be brain mediated. Remarkably, we found that PLR is instead mediated by direct retino-iridal cholinergic projections. This retina-mediated PLR acts synergistically with an iris-intrinsic mechanism that, as in other vertebrates, is mediated by melanopsin and has contribution of gap junctions between muscle fibers. In contrast, we show that lampreys lack the brain-mediated PLR. Our results suggest that two eye-intrinsic PLR mechanisms were present in early vertebrate evolution, whereas the brain-mediated PLR has a more recent origin.

This work presents a novel approach to enhancing iris recognition systems through a two-module approach focusing on low-level image preprocessing techniques and advanced feature extraction. The primary contributions of this paper include: (i) the development of a robust preprocessing module utilizing the Canny algorithm for edge detection and the circle-based Hough transform for precise iris extraction, and (ii) the implementation of Binary Statistical Image Features (BSIF) with domain-specific filters trained on iris-specific data for improved biometric identification. By combining these advanced image preprocessing techniques, the proposed method addresses key challenges in iris recognition, such as occlusions, varying pigmentation, and textural diversity. Experimental results on the Human-inspired Domain-specific Binarized Image Features (HDBIF) Dataset, consisting of 1892 iris images, confirm the significant enhancements achieved. Moreover, this paper offers a comprehensive and reproducible research framework by providing source codes and access to the testing database through the Notre Dame University dataset website, thereby facilitating further application and study. Future research will focus on exploring adaptive algorithms and integrating machine learning techniques to improve performance across diverse and unpredictable real-world scenarios.

暂无摘要。

A 65-year-old man had uneventful cataract surgery in the right eye with a toric diffractive intraocular lens (IOL) placed fully within the capsule bag. On postoperative day 1 and week 1, the IOL was well positioned and his eye was healing normally. The plan was to proceed with cataract surgery in the left eye in the near future. One month postoperatively, he presented with blurred vision, glare, and halos and was noted to have iris prolapse out of the temporal clear corneal main incision. Of interest, the patient reported some itching and eye rubbing in the early postoperative period. He was taken back to surgery by the referring doctor, and despite 2 heroic attempts to reposit and save the iris tissue, there was significant iris loss causing transillumination defects and debilitating glare and halos. Ocular examination revealed an uncorrected distance visual acuity (UDVA) of 20/40 - 2 J3 and binocular corrected distance visual acuity (CDVA) 20/30 J1 in the right eye and UDVA of 20/60 J3 and binocular CDVA of 20/25 J1 in the left eye. Manifest refraction was -0.25 -1.25 × 155 in the right eye and plano -2.25 × 090 in the left eye. Fortunately, there was no relative afferent pupillary defect, and intraocular pressures were normal off all drops. On slitlamp examination of the right eye, pertinent findings revealed a protective ptosis, trace conjunctival injection with 1 large subconjunctival polypropylene flange at 8:30 o\'clock 1.5 mm from the limbus and 1 exposed irregular polypropylene flange eroded through the conjunctiva at 10 o\'clock 0.5 mm from the limbus (Figures 1 and 2JOURNAL/jcrs/04.03/02158034-202408000-00019/figure1/v/2024-07-30T221851Z/r/image-tiffJOURNAL/jcrs/04.03/02158034-202408000-00019/figure2/v/2024-07-30T221851Z/r/image-tiff). There was a localized area of erythema and scleral thinning surrounding the exposed flange. The cornea was edematous over the main incision. The iris was disinserted with atrophic changes and a residual iridodialysis extending from 8:30 to 10 o\'clock. The trifocal IOL was fully in the capsule bag with trace fibrosis of the capsule and rotated approximately 7 degrees off the capsulotomy tab, designating the intended axis of 1 degree. The anterior chamber was deep and quiet, and the posterior segment was unremarkable with a 0.45 cup-to-disc ratio. Pertinent examination findings in the left eye included a 2 + NS cataract and a 0.45 cup-to-disc ratio. The remainder of the examination was otherwise unremarkable. What testing and surgical plan would you offer this patient? How would you counsel regarding postoperative expectations?

暂无摘要。

The purpose of this study was to establish the normative data of horizontal visible iris diameter (HVID), vertical visible iris diameter (VVID), and palpebral fissure height (PFH) in a cohort of South Indian children. The study included 1,234 children from six schools of different regions of Tamil Nadu state, India. HVID, VVID, and PFH were measured using a simple millimeter ruler by three optometrists. Based on their age, the children were divided into three groups: preprimary school children (4-5 years), primary school children (6-10 years), and high school children (11-15 years). Mean age was 4.49 ± 0.50 years, 8.00 ± 1.41 years, and 12.87 ± 1.42 years in the three groups, respectively. Mean HVID was 10.45 mm, 10.54 mm, and 10.73 mm, respectively. Mean VVID was 9.18 mm, 9.32 mm, and 9.57 mm, respectively. Similarly, mean PFH was 8.15 mm, 8.30 mm, and 8.52 mm, respectively. There was a significant difference in HVID, VVID, and PFH among the three age groups (P ≤ 0.001), as well as among male and female children in the 6-10 years age group (P ≤ 0.05) but not in the other groups. Intraclass correlation coefficient values (0.78-0.95) show good agreement among the three optometrists for all parameters. The normal range of HVID, VVID, and PFH presented in the current study can help practitioners in the diagnosis of corneal disorders, serve as a basis for the design of contact lenses, and enable accurate intraocular lens power calculations for South Indian children.

This case report describes a diagnosis of iridodialysis in an 11-year-old boy who presented with decreased vision and inflammation after direct blunt trauma to the left eye.

Fractional-order (FO) chaotic systems exhibit random sequences of significantly greater complexity when compared to integer-order systems. This feature makes FO chaotic systems more secure against various attacks in image cryptosystems. In this study, the dynamical characteristics of the FO Sprott K chaotic system are thoroughly investigated by phase planes, bifurcation diagrams, and Lyapunov exponential spectrums to be utilized in biometric iris image encryption. It is proven with the numerical studies the Sprott K system demonstrates chaotic behaviour when the order of the system is selected as 0.9. Afterward, the introduced FO Sprott K chaotic system-based biometric iris image encryption design is carried out in the study. According to the results of the statistical and attack analyses of the encryption design, the secure transmission of biometric iris images is successful using the proposed encryption design. Thus, the FO Sprott K chaotic system can be employed effectively in chaos-based encryption applications.

Lipids are compounds involved in many biologic functions including cell structure, metabolism, energy storage and are involved in signaling. A prominent lipid in these functions is cholesterol. Cholesterol also plays a part in the signaling of melanocytes, which contain melanosomes. The maturation of these melanosomes happens during melanocyte growth. The deficit of melanogenesis or melanosome maturation is associated with ocular albinism in the eye. Aberrations of melanosome maturation are also associated with pigment dispersion syndrome. Albinism and pigment dispersion manifestations are systemic. Both melanogenesis and melanocyte maturation are affected by cholesterol metabolism. Cholesterol signaling is a part of many pathways in the body, and evaluating these signals can have implications in systemic disease processes of melanogenesis and melanosome maturation, like ocular albinism and pigment dispersion. Cholesterol is carried by lipoprotein particles. Low-density lipoprotein (LDL) is usually the transport vehicle for cholesterol to reach tissues and organelles. The LDL uptake on cells often sends out a cascade of internal signaling within the cells. We describe here LDL signaling related to lipase activity changes using enzymatic methods with a kit. We describe analyses of cholesterol esters and free cholesterol with liquid chromatography and gas chromatography with or in tandem with mass spectrometry (GC-MS and LC-MS/MS). These analyses will provide insight into melanosome maturation and melanogenesis. The methods described here are applicable to all melanocytes within the body of a model mammalian organism.

Nowadays, lasers are used in various medical fields. Ophthalmology was the first medical specialty to utilize lasers in patient treatment and still remains the leading medical field that uses laser energy for both therapeutic and diagnostic purposes. The neodymium: yttrium-aluminum-garnet (Nd: YAG) laser is one of the most common lasers used in ophthalmology. It is a solid-state laser with a wavelength of 1064 nm that works on the principle of photodisruption. Since its introduction in ophthalmology over 40 years ago, it has found various applications, mainly for procedures where cutting or disruption of ocular tissue is required. Compared to surgical alternatives, the use of Nd: YAG lasers on ocular tissue is minimally invasive. In this review, we focus on the two most common ophthalmic applications of Nd: YAG laser - laser peripheral iridotomy and posterior capsulotomy. The history of the techniques, current trends, potential complications, and the prognosis for future use is discussed.