PTK GUIDED

Imaging-guided chemo-phototherapy based on multifunctional nanocarriers has emerged as a promising and high-efficient cancer treatment because of the inevitable limitations of single therapy. Herein, a near-infrared (NIR) light-activated degradable polymeric nanoplatform was fabricated for chemo-phototherapy. An NIR photosensitizer, IR780, and a chemotherapeutic drug, doxorubicin (DOX), were efficiently coloaded within a reactive oxygen species (ROS)-sensitive polymeric micelle based on an amphiphilic copolymer with degradable thioketal (TK) linkages...

A 29-year-old male was referred following a flap loss after the creation of a thin, irregular flap with a visual acuity of logMAR 0.1 with -2.0 DS-2.75 DC × 175°. Corneal topography and anterior segment optical coherence tomography revealed an irregular corneal curvature and epithelial profile. Phototherapeutic keratectomy (PTK) followed by Topography - Guided Custom Ablation Treatment (TCAT), as a modification of the topographic neutralization technique protocol, was planned to regularize the corneal surface and treat the residual refractive error...

PURPOSE: To analyze transepithelial phototherapeutic keratectomy (PTK) results using optical coherence tomography (OCT) and develop a model to guide the laser dioptric and depth settings. SETTING: Casey Eye Institute, Portland, Oregon, USA. DESIGN: Prospective nonrandomized case series. METHODS: Patients with superficial corneal opacities and irregularities had transepithelial PTK with a flying-spot excimer laser by combining wide-zone myopic and hyperopic astigmatic ablations...

Phototherapeutic keratectomy (PTK) has been used to treat anterior corneal dystrophy but may cause hyperopic shift or corneal high-order aberration. We describe the successful treatment of a case of a 43-year-old female with Thiel-Behnke corneal dystrophy, using PTK followed by wavefront-guided photorefractive keratectomy (PRK). The patient had high corneal aberration and hyperopic shift after PTK in both eyes. The corneal surface regularity index and surface asymmetric index increased after PTK and decreased after wavefront-guided PRK...

PURPOSE: To describe, with videos, the principles of excimer laser phototherapeutic keratectomy (PTK) for the treatment of corneal scars, corneal surface irregularity, and recurrent corneal erosions. METHODS: Depending on the pathology in a treated cornea, the epithelium is removed either by transepithelial PTK ablation with the excimer laser or thorough scraping with a scalpel blade. Stromal PTK can be performed with or without photorefractive keratectomy (PRK), depending on the refractive status of both eyes...

AIM: To report the long-term outcomes of optical coherence tomography (OCT)-guided transepithelial phototherapeutic keratectomy (PTK) for the management of anterior corneal scarring. METHODS: The charts of 60 patients (64 eyes) who underwent OCT-guided transepithelial PTK for anterior corneal scarring were retrospectively reviewed. The procedure involved a preoperative OCT-measured depth of treatment calculation to reduce or eliminate corneal scarring, followed by a combined myopic and hyperopic transepithelial excimer laser treatment profile established to attain the desired refractive result...

PURPOSE: To investigate preoperative and postoperative anterior and posterior keratometry and simulated corneal astigmatism in keratoconic eyes treated with collagen cross-linking combined with anterior surface normalization by partial topography-guided excimer ablation (the Athens Protocol). METHODS: Anterior and posterior corneal keratometry were measured by Scheimpflug imaging for 267 untreated keratoconic eyes. Following treatment, they were assessed 1 year postoperatively...

Biodegradable tissue engineering scaffolds are commonly fabricated from poly(lactide-co-glycolide) (PLGA) or similar polyesters that degrade by hydrolysis. PLGA hydrolysis generates acidic breakdown products that trigger an accelerated, autocatalytic degradation mechanism that can create mismatched rates of biomaterial breakdown and tissue formation. Reactive oxygen species (ROS) are key mediators of cell function in both health and disease, especially at sites of inflammation and tissue healing, and induction of inflammation and ROS are natural components of the in vivo response to biomaterial implantation...

Protein tyrosine kinases (PTKs) are attractive targets in searching for therapeutic agents against many diseases. In this study, a series of dehydroabietylamine derivatives were first determined to show PTK inhibitory activity using a high-throughput screening (HTS) method based on homogeneous time-resolved fluorescence (HTRF) technology. The structure-activity relationships of the dehydroabietylamine derivatives were established, and it was found that the compounds with a nitrogen-containing side chain had better inhibitory activity...

PURPOSE: To report the visual and anatomic outcomes of a novel technique for the management of anterior corneal scarring using optical coherence tomography (OCT)-guided transepithelial phototherapeutic keratectomy (transepithelial PTK). DESIGN: Retrospective, consecutive case series. METHODS: The charts of 22 patients with anterior corneal scarring associated with irregularities in the Bowman layer who had undergone transepithelial PTK according to a novel protocol were reviewed...

PURPOSE: To demonstrate improved effectiveness of transepithelial phototherapeutic keratectomy (PTK) where topography-guided ablation is degraded by epithelial compensation for localized irregularities. METHODS: Artemis very high-frequency digital ultrasound (ArcScan Inc., Morrison, CO) scanning was performed on five eyes (four patients) after LASIK in which a truncated nasal flap was created but the ablation was still performed, resulting in irregular astigmatism and double vision...

Concomitant with new innovations in the field of refractive surgery, therapeutic excimer laser applications like phototherapeutic keratectomy (PTK) and topography-guided customised ablation treatment are gaining high importance and undergoing rapid evolution. Nowadays, PTK is an effective treatment modality for superficial corneal pathologies. Primary indications are decreased epithelial adherence, superficial opacifications and an irregular corneal surface. For the right indication and successful treatment of corneal pathologies with PTK, a knowledge of the size, depth and nature of the pathology, as well as the refractive status of both eyes is important...

PURPOSE: The corneal change induced by refractive procedures influence both the postoperative refractive status and the ocular spherical aberration (SA). We evaluated changes in corneal SA after three types of surface ablation: phototherapeutic keratectomy (PTK), myopic photorefractive keratectomy (PRK), and myopic wavefront-guided laser epithelial keratomileusis (LASEK). METHODS: Twenty-six eyes (25 patients) were subjected to PTK 26 eyes (14 patients) to PRK, and 34 eyes (17 patients) to wavefront-guided LASEK...

This paper focuses on reviewing the roles of optical coherence tomography (OCT) on corneal surface laser ablation procedures. OCT is an optical imaging modality that uses low-coherence interferometry to provide noninvasive cross-sectional imaging of tissue microstructure in vivo. There are two types of OCTs, each with transverse and axial spatial resolutions of a few micrometers: the time-domain and the fourier-domain OCTs. Both have been increasingly used by refractive surgeons and have specific advantages...

PURPOSE: To describe and quantify the errors inherent to topography-guided ablation of irregular corneas due to natural epithelial thickness compensatory remodeling. METHODS: Artemis very high-frequency (VHF) digital ultrasound scanning (ArcScan Inc) was performed on a cornea that had undergone radial keratotomy with inferior and superior trapezoidal keratotomies, resulting 27 years later in high irregular astigmatism (+6.50 -8.00 × 101) and severe loss of corrected distance visual acuity (CDVA) to 20/50...

PURPOSE: To evaluate the results of combined aspheric wavefront-guided transepithelial excimer laser photorefractive keratectomy (PRK) and phototherapeutic keratectomy (PTK) to correct aberrations and refractive errors after radial keratotomy (RK) or keratoplasty. SETTING: Sekal Rovigo Microsurgery Centre, Rovigo, Italy. METHODS: This retrospective noncomparative consecutive case series comprised eyes having corneal wavefront-guided transepithelial PRK to correct aberrations followed by PTK (60 to 70 mum depth) without masking fluid...

PURPOSE: To demonstrate the use of anterior segment optical coherence tomography (ASOCT) in planning phototherapeutic keratectomy (PTK) removal of central corneal stromal scarring. METHODS: A 62-year-old male presented with central corneal scars associated with significant ocular surface disease. Videokeratographies obtained using 3 different systems were not reliable. ASOCT, however, provided consistent pachymetry in the presence of noncalcific stromal opacity, which extended below Bowman membrane...

PURPOSE: To describe the potential use of three-dimensional optical coherence tomography (OCT)-guided phototherapeutic keratectomy (PTK) for granular corneal dystrophy. DESIGN: : Investigative case report. METHODS: Three-dimensional volume data of 1310-nm high-speed swept-source OCT was used to simulate the effect of PTK performed for the removal of corneal opacity in a patient with granular corneal dystrophy. RESULTS: The OCT projection view was used to visualize the reduction of the area of the opacity with progressively deeper simulated ablation to determine the appropriate ablation depth...

While protein tyrosine (Tyr) kinases (PTKs) have been extensively characterized in eukaryotes, far less is known about their emerging counterparts in prokaryotes. The inner-membrane Wzc/Etk protein belongs to the bacterial PTK family, which has an important function in regulating the polymerization and transport of virulence-determining capsular polysaccharide (CPS). The kinase uses a unique two-step activation process involving intra-phosphorylation of a Tyr residue, although the molecular mechanism remains unknown...

PURPOSE: To study the changes in irregular astigmatism in patients with recurrent corneal erosion syndrome due to map-dot-fingerprint degeneration and to demonstrate that both symptomatic and asymptomatic map-dot-fingerprint degeneration/recurrent corneal erosion syndrome may be related to irregular astigmatism, which can effectively be corrected by phototherapeutic keratectomy (PTK) or standard spherical photorefractive keratectomy (PRK). METHODS: Eleven eyes with irregular astigmatism related to map-dot-fingerprint degeneration/recurrent corneal erosion syndrome with and without changes at the slit-lamp microscope were treated with PTK or spherical PRK, which was performed with a VISX S2 or S4 excimer laser...