Techniques of noncircular corneal transplantation

Purpose of review The management of peripheral corneal diseases, including Mooren's ulcer, Terrien's marginal degeneration, peripheral ulcerative keratitis and pellucid marginal degeneration is challenging. Circular grafts must either be very large, resulting in the excision of healthy tissue, or eccentric, leading to high levels of astigmatism. This review summarizes the range of noncircular keratoplasty procedures available to surgeons, in addition to their indications, and surgical techniques. Recent findings Noncircular grafts have been demonstrated to be useful in the management of peripheral corneal diseases. They are effective at providing tectonic support and also facilitate visual rehabilitation. Specifically, they produce favourable postoperative visual and astigmatic outcomes. The evidence relating to these procedures is largely limited to case reports and case series, with no large-scale studies available. Summary Noncircular keratoplasty procedures are useful in the management of peripheral corneal diseases, which is typically difficult. There is a need for larger studies to investigate the relative advantages and disadvantages of these procedures and further characterize their outcomes.
Source: Current Opinion in Ophthalmology - Category: Opthalmology Tags: CORNEAL AND EXTERNAL DISORDERS: Edited by Shahzad I. Mian Source Type: research

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"Harmonization" of donor and recipient tomography in corneal transplantation. Z Med Phys. 2020 Jun 15;: Authors: Mäurer S, Seitz B, Langenbucher A Abstract The applicability of donor and recipient tissue matching in corneal transplantation ("harmonization") to reduce residual astigmatism after keratoplasty was simulated using Matlab software. The height profile of the donor and recipient corneas was measured using the anterior segment optical coherence tomography (AS-OCT) Casia 2. After best fit of the donor button in the recipient bed the mean height difference as the mismatc...
Source: Zeitschrift fur Medizinische Physik - Category: Radiology Authors: Tags: Z Med Phys Source Type: research
Conclusion: The anterior corneal surface BFS value can be used as a reference in selecting the initial BC of tricurve RGP contact lens to achieve the best fitting and reducing the chair time of patients after PK.
Source: Indian Journal of Ophthalmology - Category: Opthalmology Authors: Source Type: research
This study aimed to investigate the changes in postoperative ocular biometric parameters in end-stage renal disease patients who underwent renal transplantation.Material and methodsThis retrospective study included a total of 33 eyes of 33 patients. The ocular biometric measurements which were evaluated were axial length (AL), central corneal thickness (CCT), anterior chamber depth (ACD), corneal keratometry (K1 and K2), degree of astigmatism, lens thickness (LT), and intraocular pressure (IOP). Refractive prediction error (RE) was calculated before and after renal transplantation using the same diopter (D) for intraocular...
Source: International Ophthalmology - Category: Opthalmology Source Type: research
CONCLUSION: Because of the undisputed clinical advantages, especially in eyes with advanced keratoconus, excimer laser trephination with orientation cogs/notches is currently favored in the routine daily practice in Homburg/Saar. PMID: 31696253 [PubMed - as supplied by publisher]
Source: Der Ophthalmologe - Category: Opthalmology Authors: Tags: Ophthalmologe Source Type: research
AbstractPurposeTo investigate the feasibility of intrastromal lenticule insertion to restore corneal shape in a model of ectatic human cornea.MethodsFor this experimental ex vivo study on 34 human corneas unsuitable for transplantation, 17 corneas were thinned by decentralized posterior excimer laser ablation to 200  μm thickness and 6.5 mm diameter and then inflated up to 100 mm Hg to expose the ectasias (recipient corneas). Pachimetry and topography were obtained. Stromal lenticules of the same diameter and thickness as the ectasias were shaped with a femtosecond laser from the remaining 17 donor cornea...
Source: International Ophthalmology - Category: Opthalmology Source Type: research
Conclusions: In eyes that underwent prior RK, DALK by manual dissection should be considered as a preferable surgical technique.
Source: Cornea - Category: Opthalmology Tags: Clinical Science Source Type: research
Rationale: Limbal dermoids are choristomas known as congenital benign tumors found in abnormal locations. Despite the benign nature, enlarging limbal dermoids may cause visual abnormalities by cornea infiltration with fat component, visual axis invasion, gradually induced corneal astigmatism, and finally result in anisometropic amblyopia. Here we report a rare case of progressive, large pediatric corneal limbal dermoid in a newborn, managed with tissue glue-assisted monolayer amniotic membrane transplantation. Patient concerns: A 1-day-old male baby (gestational age, 36 ± 6 weeks; birth body weight, 2785 gr...
Source: Medicine - Category: Internal Medicine Tags: Research Article: Clinical Case Report Source Type: research
Nadisha P Singh, Dalia G Said, Harminder Singh DuaIndian Journal of Ophthalmology 2018 66(9):1239-1250 Lamellar keratoplasty (LK) has revolutionized corneal graft surgery in several ways. Deep anterior LK (DALK) has eliminated risk of failure due to endothelial rejection. Endothelial keratoplasty (EK) has almost eliminated induced astigmatism and the “weak” graft–host junction as seen with penetrating keratoplasty (PK) and also reduced the risk of endothelial rejection. LK provided new insights into posterior corneal anatomy that led to better understanding and performance of DALK and to the development ...
Source: Indian Journal of Ophthalmology - Category: Opthalmology Authors: Source Type: research
Conclusions: After a transient technical learning period, in situ CD excision proved to be a method of donor cornea recovery with similar cultivation performance and clinical results compared with whole eye enucleation. It also may have led to higher willingness to donate, possibly because of better acceptance by the relatives of the deceased.
Source: Cornea - Category: Opthalmology Tags: Clinical Science Source Type: research
Conclusions: Twelve months postoperatively, the BSCVA improved significantly, the lines of vision increased, and astigmatism, corneal best-fit sphere, mean keratometry, corneal thickness, corneal root mean square total, and corneal spherical aberrations decreased. TG-PRK with MMC is a good alternative for correcting post-PKP cases with irregular astigmatism with elevated higher-order aberrations.
Source: Cornea - Category: Opthalmology Tags: Clinical Science Source Type: research
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