Special Cases in the Diagnosis and Treatment of Fungal Keratitis
Mahendra Rai, Marcelo Luís Occhiutto in Mycotic Keratitis, 2019
As the normal cornea has neither vascular nor lymphatic vessels, it has a relative immune privilege. A large diameter makes the preparation of the graft close to the corneal limbus, which is normally endowed with both vascular and lymphatic vessels, leading to an increased risk of immunological rejection after surgery. Therefore, patients with a graft larger than 9 mm are often given oral cyclosporine A, which can prevent and treat immune rejection. Immune rejection might not occur during the medication, but due to its weak anti-inflammatory and anti-toxic effects, patients may suffer obvious anterior segment inflammation and unresolved congestion and corneal edema. Proper use of glucocorticoids after keratoplasty for FK to not only control the inflammation of the eye but also reduce the fungal recurrence is essential for improving the success rate of surgery.
Describe the structure and function of the ciliary body
Nathaniel Knox Cartwright, Petros Carvounis in Short Answer Questions for the MRCOphth Part 1, 2018
The ciliary body is the middle part of the uveal tract and is continuous anteriorly with the periphery of the iris and posteriorly with the choroid. The ciliary body forms a ring that runs around the inside of the anterior sclera, measuring about 6 mm wide (6.5 mm temporally, 5.5 mm nasally) and extending forward to the scleral spur and backward to the ora serrata. The surface landmark of the anterior aspect of the ciliary body is the point 1.5 mm posterior to the corneal limbus.
The cornea
Mary E. Shaw, Agnes Lee in Ophthalmic Nursing, 2018
Forming the anterior one-sixth of the eyeball, the cornea is a transparent structure which fits into the surrounding sclera like a watch-glass. It is convex, avascular and highly sensitive. The site where the cornea becomes continuous with the sclera is known as the corneal limbus.
Comparing the Differences in Slowing Myopia Progression by Riboflavin/Ultraviolet A Scleral Cross-linking before and after Lens-induced Myopia in Guinea Pigs
Published in Current Eye Research, 2022
Lingbo Lai, Xiaotong Lv, Xiaowei Wu, Yushan Xu, Zhe Chen, Yu Li, Mingshen Sun, Fengju Zhang
5 pieces of 3 mm × 8 mm scleral strips in each group were prepared for the tensile test. The scleral strips were dissected longitudinally from the corneal limbus at the 10 o’clock position. The cross-linked area was located in the center of the scleral strip. The thickness (H0) of the fresh scleral strips was determined by taking the mean of 3 readings at different locations with a micrometer, where the measuring range was 6 mm and the interval was about 2 mm. The strips were clamped horizontally with a distance (L0) of 6 mm between the jaws of a microcomputer-controlled biomaterial testing system (BOSE ElectroForce 3100; Bose ElectroForce Systems Group, Minnesota, USA). After the deformation-load test at a stress of 0.01 MPa for 10 cycles, the strain was increased linearly at a velocity of 2 mm/min, the stress was recorded until the strips broke. Normal saline was applied to avoid strips drying during the tests. The stress and strain in the scleral strips were computed as
Anterior vestibule salvaging technique to limit silicone orbital implant extrusion following evisceration
Published in Orbit, 2019
Nicholas A. Moore, Roxana Fu, Jeremy Clark, Mark Prendes, William R. Nunery, Richard A. Burgett, H.B. Harold Lee
After general anesthesia was initiated, a local anesthetic retrobulbar injection of 3 mL of 1% Lidocaine with Epinephrine and 0.75% Bupivacaine in a 1:1 mixture was administered. An eyelid speculum was placed and Westcott scissors created a 360° limbal conjunctival peritomy. Conjunctiva and anterior Tenon’s capsule were dissected from the corneal limbus. A full-thickness sclerotomy was created with an 11-bard parker blade immediately posterior to the limbus avoiding any anterior epithelial tissue. Westcott scissors were used to perform a 360° keratectomy. An evisceration curette (spoon) was placed in the suprachoroidal space separating uveal tissues from sclera. Dissection directed anterior–posteriorly and centripetally was performed until the intraocular contents could be delivered. Care was taken to remove all visible uveal tissue.
Connexins in the development and physiology of stem cells
Published in Tissue Barriers, 2021
Anaclet Ngezahayo, Frederike A. Ruhe
Adult multipotent stem cells originating from different tissues, such as the corneal limbus, periodontal ligament, skin, bone marrow, or fat tissue, have been analyzed.95,96 With respect to Cx expression, Cx43, Cx32 and Cx31.9 are normally expressed.97,98 Other additional Cx isoforms, such as Cx26, Cx37, and Cx45, are also expressed but to a lesser extent.54,98,99 Among the Cx isoforms recognized by PCR in MSCs, only Cx43 is expressed, which has been revealed by western blotting or immunostaining experiments.54,97,100,101 The expression of other isoforms, such as Cx31.9, Cx32, and Cx45, has been sporadically reported.97,101 Due to the availability of analytical tools such as antibodies, Cx43 has been intensively studied in the stem cell research field. The danger is to extrapolate the results on Cx43 to other isoforms or to consider the other Cx isoforms as unimportant for the physiology and differentiation of the different stem cells. Careful observation of the cells in development has revealed that other Cx isoforms play a role and should be considered as well. The challenge is to invest in the development of tools and to take time to understand the specific role of each Cx isoform on stem cell physiology and differentiation.
Related Knowledge Centers
- Aniridia
- Cornea
- Epithelium
- Eye
- Stratified Squamous Epithelium
- Sclera
- Cancer
- Limbal Stem Cell
- Limbal Ring
- Iris