scholarly journals Keratoplasty for keratoconus: advantages and disadvantages

2022 ◽  
Vol 14 (4) ◽  
pp. 130-136
Author(s):  
M. M. Bikbov ◽  
E. L. Usubov ◽  
A. F. Zaynetdinov
Keyword(s):  
Corneal Transplantation ◽  
Loss Of Vision ◽  
Corneal Ectasia ◽  
Advantages And Disadvantages ◽  
Irregular Astigmatism

Keratoconus is a progressive bilateral corneal ectasia, accompanied by loss of vision due to high irregular astigmatism, which is the leading indication for corneal transplantation. The review presents a variety of surgical corneal transplantation techniques for keratoconus available today and discussed their advantages and disadvantages.

Simultaneous transepithelial topographic-guided laser and cross-linking to correct irregular astigmatism in a pediatric patient

2021 ◽  
pp. 112067212110464
Author(s):  
Luca Buzzonetti ◽  
Gianni Petrocelli ◽  
Sergio Petroni ◽  
Paola Valente ◽  
Giancarlo Iarossi
Keyword(s):  
Pediatric Patient ◽  
Penetrating Trauma ◽  
Cross Linking ◽  
Corneal Ectasia ◽  
Irregularity Index ◽  
Quality Of Vision ◽  
Corrected Distance Visual Acuity ◽  
Post Traumatic ◽  
Irregular Astigmatism

Purpose: To evaluate an original approach for treating corneal ectasia and irregular astigmatism secondary to penetrating trauma in a pediatric patient. Case report: An 11 year old patient had a penetrating trauma in right eye when he was two and the refractive error was +1.50 diopters sphere −6.00 diopters cylinder axis 95°. To correct irregular astigmatism, the patient underwent simultaneous transepithelial topographic-guided laser Central Corneal Remodeling (CCR) and Corneal Cross-linking (CXL) in the attempt to regularize corneal ectasia and to improve the quality of vision. Uncorrected and Corrected Distance Visual Acuity were measured using Efficacy and Safety indexes; objective and subjective qualities of vision were evaluated using respectively corneal morphological irregularity index and National Eye Institute Visual Function questionnaires. Conclusions: Twelve month follow up suggests that simultaneous CCR and CXL could be effective to improve the quality of vision and to halt the progression of post-traumatic ectasia in pediatric patients.

Shaped corneal transplantation surgery

2020 ◽  
Vol 105 (1) ◽  
pp. 9-16 ◽  
Author(s):  
Pranita Sahay ◽  
Louis Julian Stevenson ◽  
Tushar Agarwal ◽  
Bhavana Sharma ◽  
Namrata Sharma ◽  
...  
Keyword(s):  
Femtosecond Laser ◽  
Corneal Transplantation ◽  
Lamellar Keratoplasty ◽  
Visual Rehabilitation ◽  
Advantages And Disadvantages ◽  
Transplantation Surgery ◽  
Complex Wound

Since its inception in 1905, keratoplasty techniques have continuously evolved. Shaped keratoplasty procedures have allowed corneal surgeons to use complex graft–host junctions and non-circular graft designs to optimise wound strength and healing, facilitate early suture removal and expedite visual rehabilitation. While this was initially limited to penetrating procedures, shaped lamellar keratoplasty techniques have since emerged. Furthermore, the arrival of femtosecond laser has dramatically increased the range of graft designs available to surgeons, due to the technology’s ability to precisely cut complex wound edges. This review describes the broad range of shaped keratoplasty grafts currently available and elaborates on their respective advantages and disadvantages in relation to conventional keratoplasty.

Irregular Astigmatism Management Using SPOT Scleral Lenses in the Treatment of Corneal Ectasia and Penetrating Keratoplasty

2021 ◽  
Vol Publish Ahead of Print ◽  
Author(s):  
Valentin Navel ◽  
Jean-Vincent Barriere ◽  
Romain Joubert ◽  
Adrien Coutu ◽  
Stephanie L. Watson ◽  
...  
Keyword(s):  
Penetrating Keratoplasty ◽  
Corneal Ectasia ◽  
Irregular Astigmatism

scholarly journals Descemet membrane endothelial keratoplasty in a patient with iris-fixated intraocular lens and prior radial keratotomy: a case report

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Anvesh Annadanam ◽  
Timothy Soeken ◽  
Manjool Shah ◽  
Nambi Nallasamy
Keyword(s):  
Intraocular Lens ◽  
Corneal Transplantation ◽  
Anterior Segment ◽  
Descemet Membrane Endothelial Keratoplasty ◽  
Case Presentation ◽  
Radial Keratotomy ◽  
Uncorrected Visual Acuity ◽  
History Of ◽  
Irregular Astigmatism ◽  
Fuchs Dystrophy

Abstract Background Anterior segment surgeries such as cataract surgery, intraocular lens (IOL) repositioning, and radial keratotomy (RK) may hasten endothelial dysfunction, particularly in the context of pre-existing Fuchs dystrophy, necessitating future corneal transplantation. Case presentation A 68-year-old woman with a history of RK with associated irregular astigmatism in both eyes and iris-fixated intraocular lens (IF-IOL) in the left eye presented with six months of decreased vision in the left eye. She was found to have Fuchs dystrophy and underwent DMEK surgery. She had an uncomplicated postoperative course, with uncorrected visual acuity improving to 20/20 three months after surgery. Conclusion To our knowledge, this is the first reported case of a highly successful DMEK surgery in a patient with prior RK and IF-IOL.

Irregular Astigmatism After Corneal Transplantation—Efficacy and Safety of Topography-Guided Treatment

Cornea ◽  
2016 ◽  
Vol 35 (1) ◽  
pp. 30-36 ◽  
Author(s):  
Inês Laíns ◽  
Andreia M. Rosa ◽  
Marta Guerra ◽  
Cristina Tavares ◽  
Conceição Lobo ◽  
...  
Keyword(s):  
Corneal Transplantation ◽  
Efficacy And Safety ◽  
Irregular Astigmatism

scholarly journals Conventional and Pattern Laser Applications in Diabetic Retinopathy and Diabetic Macular Edema

2018 ◽  
pp. 170-176
Keyword(s):  
Diabetes Mellitus ◽  
Diabetic Retinopathy ◽  
Macular Edema ◽  
Diabetic Macular Edema ◽  
Age Groups ◽  
Laser Applications ◽  
Loss Of Vision ◽  
Advantages And Disadvantages ◽  
Pan Retinal Photocoagulation ◽  
Retinal Photocoagulation

Diabetes mellitus leads to two major complications, diabetic retinopathy (DRP) and diabetic macular edema (DME), resulting in loss of vision. Diabetes mellitus is the most common cause of loss of vision when all age groups are taken into account. However, this complication can be prevented or delayed with various treatments, especially strict blood glucose regulation. Laser, anti-VEGF, and corticosteroids are used in the treatment of DME. Laser therapy is applied as a focal / grid or pan-retinal photocoagulation. Nowadays, different lasers are presented to use in the treatment in DRP and DME. Each has different advantages and disadvantages. This article discusses the characteristics of lasers used in the treatment of DRP and DME.

scholarly journals The potential role of bioengineering and three-dimensional printing in curing global corneal blindness

2018 ◽  
Vol 9 ◽  
pp. 204173141876986 ◽  
Author(s):  
Parker E Ludwig ◽  
Trevor J Huff ◽  
Jorge M Zuniga
Keyword(s):  
Corneal Transplantation ◽  
Three Dimensional ◽  
Synthetic Polymers ◽  
Cellular Level ◽  
Surrounding Tissue ◽  
Corneal Tissue ◽  
Natural Polymers ◽  
Three Dimensional Printing ◽  
Advantages And Disadvantages ◽  
Tissue Grafts

An insufficiency of accessible allograft tissue for corneal transplantation leaves many impaired by untreated corneal disease. There is promise in the field of regenerative medicine for the development of autologous corneal tissue grafts or collagen-based scaffolds. Another approach is to create a suitable corneal implant that meets the refractive needs of the cornea and is integrated into the surrounding tissue but does not attempt to perfectly mimic the native cornea on a cellular level. Materials that have been investigated for use in the latter concept include natural polymers such as gelatin, semisynthetic polymers like gelatin methacrylate, and synthetic polymers. There are advantages and disadvantages inherent in natural and synthetic polymers: natural polymers are generally more biodegradable and biocompatible, while synthetic polymers typically provide greater control over the characteristics or property adjustment of the materials. Additive manufacturing could aid in the precision production of keratoprostheses and the personalization of implants.

Cryogenic atomic force microscopy

1991 ◽  
Vol 49 ◽  
pp. 54-55
Author(s):  
K. A. Fisher ◽  
M. G. L. Gustafsson ◽  
M. B. Shattuck ◽  
J. Clarke
Keyword(s):  
Room Temperature ◽  
Rapid Freezing ◽  
Cryogenic Temperatures ◽  
Soft Or ◽  
Electrically Conductive ◽  
Force Microscopy ◽  
Flexible Molecules ◽  
Advantages And Disadvantages ◽  
Atomic Force ◽  
Chemical Perturbation

The atomic force microscope (AFM) is capable of imaging electrically conductive and non-conductive surfaces at atomic resolution. When used to image biological samples, however, lateral resolution is often limited to nanometer levels, due primarily to AFM tip/sample interactions. Several approaches to immobilize and stabilize soft or flexible molecules for AFM have been examined, notably, tethering coating, and freezing. Although each approach has its advantages and disadvantages, rapid freezing techniques have the special advantage of avoiding chemical perturbation, and minimizing physical disruption of the sample. Scanning with an AFM at cryogenic temperatures has the potential to image frozen biomolecules at high resolution. We have constructed a force microscope capable of operating immersed in liquid n-pentane and have tested its performance at room temperature with carbon and metal-coated samples, and at 143° K with uncoated ferritin and purple membrane (PM).

A conduction-cooled stage for high-resolution Cryo-SEM

1992 ◽  
Vol 50 (2) ◽  
pp. 1282-1283
Author(s):  
John G. Sheehan
Keyword(s):  
High Resolution ◽  
Liquid Nitrogen ◽  
Mechanical Stability ◽  
Cooling System ◽  
Cold Trap ◽  
Nitrogen Gas ◽  
Particulate Suspensions ◽  
Advantages And Disadvantages ◽  
Convection Cooling ◽  
Styrene Butadiene

The goal is to examine with high resolution cryo-SEM aqueous particulate suspensions used in coatings for printable paper. A metal-coating chamber for cryo-preparation of such suspensions was described previously. Here, a new conduction-cooling system for the stage and cold-trap in an SEM specimen chamber is described. Its advantages and disadvantages are compared to a convection-cooling system made by Hexland (model CT1000A) and its mechanical stability is demonstrated by examining a sample of styrene-butadiene latex.In recent high resolution cryo-SEM, some stages are cooled by conduction, others by convection. In the latter, heat is convected from the specimen stage by cold nitrogen gas from a liquid-nitrogen cooled evaporative heat exchanger. The advantage is the fast cooling: the Hexland CT1000A cools the stage from ambient temperature to 88 K in about 20 min. However it consumes huge amounts of liquid-nitrogen and nitrogen gas: about 1 ℓ/h of liquid-nitrogen and 400 gm/h of nitrogen gas. Its liquid-nitrogen vessel must be re-filled at least every 40 min.

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