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Biomedical subjects

Farhad Hafezi

Publications and source records attributed to Farhad Hafezi.

At least 19 recordsLinked to original sources
PubMed2026

Second-Generation ELZA-sub400 Protocol: Individualized High-Fluence Cross-Linking for Ultra-Thin Keratoconus Corneas.

PURPOSE: To evaluate the safety and efficacy of a second-generation individualized corneal cross-linking (CXL) protocol (ELZA-sub400) using high-fluence UV-A irradiation in ultrathin ectatic corneas. DESIGN: Retrospective, single-center, consecutive interventional case series. METHODS: Twenty-nine eyes of 24 patients with progressive keratoconus or post-LASIK ectasia and a post-soak intraoperative thinnest stromal thickness <400 &#xb5;m were included. After epithelial removal and riboflavin soaking, continuous UV-A irradiation (365 nm) at 3 or 9 mW/cm&#xb2; was delivered with total fluence titrated up to 10 J/cm&#xb2; based on intraoperative ultrasound pachymetry and a previously published nomogram targeting an uncross-linked stromal margin of approximately 70 &#xb5;m above the endothelium. Outcomes were assessed at baseline and up to 12 months using corrected distance visual acuity (CDVA) and corneal parameters measured using Scheimpflug tomography and anterior segment OCT (AS-OCT) with Placido-based topography. The main outcome measure was the proportion of eyes without progression at 12 months, defined as <1.0 D increase in maximum keratometry (Kmax). Secondary outcomes included changes in CDVA, refraction, Kmax, stromal thickness, demarcation line depth, densitometry, and safety parameters. RESULTS: At 12 months, 22/29 eyes (76%; 95% CI, 57.9%-87.8%) met the nonprogression criterion. Mean change in Kmax was -0.77 &#xb1; 5.10 D (95% CI, -2.71 to 1.17; P = .418). Mean demarcation line-to-anterior stroma distance was 205 &#xb1; 64 &#xb5;m (95% CI, 180.7-229.3), and demarcation line-to-endothelium distance was 64 &#xb5;m (IQR, 49-152). All demarcation lines remained within the stromal layer; 15/29 eyes (51.7%) had a demarcation line located &#x2264;70 &#xb5;m from the endothelium. Median CDVA changed from 0.10 to 0.32 logMAR (P = .142). Minimum stromal thickness showed a median change of -4.0 &#xb5;m (P = .309). No significant change was observed in densitometry, and no eye developed deep stromal haze or endothelial decompensation. CONCLUSIONS: Second-generation ELZA-sub400 CXL halted ectasia progression in 76% of ultrathin corneas at 12 months and was associated with an acceptable short-term safety profile, including stromal-confined demarcation line formation and no observed endothelial decompensation. The numerical decline in spectacle CDVA observed in this severely affected cohort did not reach statistical significance but is clinically important and warrants confirmation in larger prospective studies.

Humans↗
PubMed2006

Q-factor customized ablation profile for the correction of myopic astigmatism.

PURPOSE: To compare the results of the Q-factor customized aspheric ablation profile with the wavefront-guided customized ablation pattern for the correction of myopic astigmatism. SETTING: Institute for Refractive and Ophthalmic Surgery, Zurich, Switzerland. METHODS: Thirty-five patients were enrolled in a controlled study in which the nondominant eye was treated with the Q-factor customized profile (custom-Q study group) and the dominant eye was treated with wavefront-guided customized ablation (control group). Preoperative and 1-month postoperative high-contrast visual acuity, low-contrast visual acuity, and glare visual acuity, as well as aberrometry and asphericity of the cornea, were compared between the 2 groups. All eyes received laser in situ keratomileusis surgery, and the laser treatment was accomplished with the Wavelight Eye-Q 400 Hz excimer laser. RESULTS: For corrections up to -9 diopters (D) of myopia, there were no statistically significant differences between the 2 groups regarding any visual or optical parameter except coma-like aberrations (3rd Zernike order), where the wavefront-guided group was significantly better 1 month after surgery (P = .002). For corrections up to -5 D (spherical equivalent), the Q-factor optimized treated eyes had a significantly smaller shift toward oblate cornea: DeltaQ15 = 0.25 in Q-factor customized versus DeltaQ15 = 0.38 in wavefront-guided treatment (P = .04). CONCLUSIONS: Regarding safety and refractive efficacy, custom-Q ablation profiles were clinically equivalent to wavefront-guided profiles in corrections of myopia up to -9 D and astigmatism up to 2.5 D. Corneal asphericity was less impaired by the custom-Q treatment up to -5 D of myopia.

Adult↗
PubMed2006

Customized ablation algorithm for the treatment of steep central islands after refractive laser surgery.

Steep central island (SCI) formation after photorefractive keratectomy (PRK) and laser in situ keratomileusis (LASIK) represents a major drawback in the visual rehabilitation of patients after refractive laser surgery. Because of the small size of SCIs, current ablation algorithms are unable to properly calculate an ablation pattern for customized retreatment. We present the use of a new ablation algorithm for the treatment of SCIs that occurred after PRK or LASIK surgery. This algorithm uses a smaller zone of approximation and takes into account the spherical shift induced by removal of the SCI. In all 3 eyes treated, best spectacle-corrected visual acuity increased to 20/16 and remained stable at the 1- and 3-month follow-up, with disappearance of the SCI in corneal topography. This new treatment algorithm may be of benefit to patients experiencing visual side effects due to SCI formation after PRK or LASIK surgery.

Algorithms↗
PubMed2006

Corneal cross-linking-induced stromal demarcation line.

PURPOSE: Corneal collagen cross-linking by UVA/riboflavin (X-linking) represents a new method for the treatment of progressive keratoconus and currently is under clinical study. To avoid UVA irradiation damage to the corneal endothelium, the parameters for X-linking are set in a way that effective treatment occurs only in the first 300 microm of the corneal stroma. Here, X-linking not only strengthens the biomechanical properties of the cornea but also induces keratocyte apoptosis. To date, the effectiveness of treatment could be monitored only indirectly by postoperative follow-up corneal topographies or using corneal confocal microscopy. Here we describe a corneal stromal demarcation line indicating the transition zone between cross-linked anterior corneal stroma and untreated posterior corneal stroma. The demarcation line is biomicroscopically detectable in slit-lamp examination as early as 2 weeks after treatment. METHODS: X-linking was performed in 16 cases of progressive keratoconus, and corneas were examined biomicroscopically and by means of corneal topography and pachymetry before and after treatment. RESULTS: In 14 of 16 cases, a thin stromal demarcation line was visible at a depth of approximately 300 microm over the whole cornea after X-linking treatment. CONCLUSION: This newly observed demarcation line may result from differences in the refractive index and/or reflection properties of untreated versus X-linked corneal stroma and represents an effective tool to biomicroscopically easily monitor the depth of effective X-linking treatment in keratoconus.

Adolescent↗
PubMed2006

Safe abdominoplasty with extensive liposuctioning.

In a review of the recent literature, liposuction and tumescent fluid injection are accompanied by hazards of ischemia, flap necrosis, and wound dehiscence at the time of abdominoplasty. The problems that generate complaints from patients and dissatisfaction with tummy tuck surgery are: fullness of flanks and epigastric areas, lack of a posterior lumbar curve, hanging skin over the incision line, and visible scars over the flanks and beyond underwear or swimming suit coverage. The purpose of this article is to introduce modalities to perform liposuctioning of the whole abdomen without confronting the danger of ischemia or flap necrosis. Wide lipoaspiration at the time of abdominoplasty and removing the flanks and epigastric fullness result in a shorter incision line and more natural-looking abdomen. In this article, the authors explain their experience using a new method to omit the complications of classic abdominoplasty surgery in 56 cases performed over a 3-year period (2000-2003).

Adult↗
PubMed2006

Management of the thick-skinned nose: A more effective approach.

A bulky nose is a challenging issue to manage, and surgeons have not found the ultimate solution to this problem in the evolution of rhinoplastic surgery. Because of the multiplicity of techniques and controversies published in the literature, it has become confusing for the operating surgeon to find the most appropriate and effective way of solving this frustrating dilemma. The subcutaneous fat is the thickest in the supratip area, and the soft tissue thickness over the tip of the nose varies considerably from patient to patient. The focus of this study was to find a method for reducing the overlying soft tissue of the tip for better re-draping of skin over the nasal skeleton. The hallmark of this technique is to undermine the nasal skin in two layers. We believe that soft tissue trimming in biplane dissection can minimize the thickness of the tip skin in a relatively safe and homogeneous way. With this report we introduce a new method of dissection of nasal soft tissue and of trimming it in different areas of the nose for different purposes. In the authors' opinion, this approach is one of the most effective ways of handling unpliable, thick nasal skin.

Adolescent↗
PubMed2005

Compound developmental eye disorders following inactivation of TGFbeta signaling in neural-crest stem cells.

BACKGROUND: Development of the eye depends partly on the periocular mesenchyme derived from the neural crest (NC), but the fate of NC cells in mammalian eye development and the signals coordinating the formation of ocular structures are poorly understood. RESULTS: Here we reveal distinct NC contributions to both anterior and posterior mesenchymal eye structures and show that TGFbeta signaling in these cells is crucial for normal eye development. In the anterior eye, TGFbeta2 released from the lens is required for the expression of transcription factors Pitx2 and Foxc1 in the NC-derived cornea and in the chamber-angle structures of the eye that control intraocular pressure. TGFbeta enhances Foxc1 and induces Pitx2 expression in cell cultures. As in patients carrying mutations in PITX2 and FOXC1, TGFbeta signal inactivation in NC cells leads to ocular defects characteristic of the human disorder Axenfeld-Rieger's anomaly. In the posterior eye, NC cell-specific inactivation of TGFbeta signaling results in a condition reminiscent of the human disorder persistent hyperplastic primary vitreous. As a secondary effect, retinal patterning is also disturbed in mutant mice. CONCLUSION: In the developing eye the lens acts as a TGFbeta signaling center that controls the development of eye structures derived from the NC. Defective TGFbeta signal transduction interferes with NC-cell differentiation and survival anterior to the lens and with normal tissue morphogenesis and patterning posterior to the lens. The similarity to developmental eye disorders in humans suggests that defective TGFbeta signal modulation in ocular NC derivatives contributes to the pathophysiology of these diseases.

Animals↗
PubMed2005

Aesthetic septorhinoplasty in the burned nose.

Patients who have survived thermal injuries to the face suffer severe disfigurement from the devastating deformities of full-thickness facial burns. The nose is the prominent central organ of the face, which has crucial effect on Aesthetic appearance. The plastic surgeon's role to deal with such cases is to undertake procedures to produce a more pleasant look although the target organ could be the non-burned areas of the face. It is a common belief that surgical intervention under the scarred or grafted nose is risky and may result in skin or covering graft necrosis. For this reason, plastic surgeons are cautious and hesitate to perform Aesthetic surgery on burn scarred tissue. We present 13 cases, 10 women and three men with complete or subtotal nasal burn. Classic Aesthetic Rhinoplasty operations were performed to create a better appearance and correct any internal or external deviations. These procedures are carried out under severely burned skins, or previously grafted and reconstructed noses. Cases were followed for about a one-year period. There was no necrosis in any part of skin after surgery. We believe that Aesthetic rhinoplasty can be done safely in these victims with pleasing outcome. The problems that we encountered in these cases were irregularities of burned alar margins, multiple operations and intractable nasal deviation in severe cases.

Adolescent↗
PubMed2005

Two-step procedure to enlarge small optical zones after photorefractive keratectomy for high myopia.

We describe a method for the visual rehabilitation of patients with small optical zones and related complaints after photorefractive keratectomy (PRK) and laser in situ keratomileusis for high myopia. In many of these cases from the early 1990s, low central corneal thickness in combination with residual myopia did not allow for enlargement of the small optical zone by a topography-guided treatment in the first instance. We therefore perform, as a first step, a clear lens exchange aiming at hyperopia. This enables us to perform, as a second step, a topography-guided customized PRK with marked enlargement of the optical zone. Such 2-step procedures may be of great benefit to patients with small optical zones and low central corneal thickness.

Adult↗
PubMed2004

Prevention of hanging columella in open rhinoplasty.

In this article we discuss the anatomy of the nasal base and explain the causes of postoperative hanging columella, distinguishing this entity from similar deformities with which it can be confused. We suggest measures that could be helpful in preventing this deformity. We performed external-approach rhinoplasty with the dome suturing method in 82 consecutive patients (64 women and 18 men) from 17 to 44 years of age (mean age, 22 years). Comparative measurements of the alar-columellar complex were made before and after operation. Among the 48 patients with conventional tip suturing (38 women and 10 men), 19 true hanging columellae were detected. In the 34 patients with a modified dome approximation (26 women and 8 men), no more than 5 cases of true deformity were diagnosed.

Adult↗
PubMed2002

Facial reconstruction using the visor scalp flap.

In male burn victims, scar may cause grotesque disfigurement to the upper lip and lower face. There are many ways to address the problem, for simple skin grafting to complex flaps. Bipedicle scalp flaps are used sporadically for reconstruction of the upper lip. In this article, the use of bitemporal artery hair-bearing flap for reconstruction of the moustache and beard area in nine cases as a substitute for facial deformed skin is described. The results indicate that the scalp flap is one of the best-matched flaps for reconstruction of the mid and lower part of the male face. As a result of choosing the proper size of the flap, use of the tissue expander is omitted, the donor site may be closed primarily and early return of the patient to normal life is guaranteed. Although, the width of the flap is not sufficient enough to cover the whole lower face and the cheeks, it is enough to imitate a normal face and give a pleasant appearance.

Adolescent↗
PubMed2002

Fra-1 substitutes for c-Fos in AP-1-mediated signal transduction in retinal apoptosis.

Lack of the AP-1 member c-Fos protects photoreceptors against light-induced apoptosis, a model for retinal degeneration. In mice, light damage increases the activity of the transcription factor AP-1, while pharmacological suppression of AP-1 prevents apoptosis, suggesting the involvement of pro-apoptotic AP-1 target genes. Recently, however, it was shown that photoreceptors expressing Fra-1 in place of c-Fos (Fos (Fosl1/Fosl1) ) are apoptosis competent despite the lack of transactivation domains in Fra-1. Here, we show that morphological features of light-induced apoptosis were indistinguishable in Fos (Fosl1/Fosl1) and wild-type mice. Furthermore, light exposure comparably increased AP-1 activity in both genotypes. Opposite to wild-type mice, Fra-1, but not c-Fos, was detectable in AP-1 complexes of Fos (Fosl1/Fosl1) mice. Importantly, AP-1 responsiveness for glucocorticoid receptor-mediated inhibition was preserved in Fos (Fosl1/Fosl1) mice. Thus, Fra-1 takes over for c-Fos in pro- and anti-apoptotic signal transduction. As Fra-1 lacks transactivation domains, AP-1 may not induce, but rather suppress genes in retinal light damage.

Animals↗
PubMed2000

Apoptosis in the Retina: The Silent Death of Vision.

Pathogenetic mechanisms of retinal degeneration include cell loss by apoptosis. This gene-regulated mode of single-cell death occurs in a number of widespread human diseases such as neurodegeneration. The knowledge of genes and signaling in retinal apoptosis is expanding and opens up therapeutic strategies to ameliorate blinding retinal diseases.

Journal Article↗
PubMedDate not supplied

Conservative treatment of vertical diplopia in a patient with silent sinus syndrome.

Silent sinus syndrome is a rare disease of the maxillary sinus characterized by bony absorption processes leading to progressive sinus wall thinning with consecutive enophthalmos and hypoglobus. It represents a benign cause of acquired enophthalmos and is often accompanied by painless vertical diplopia, the latter treated surgically in all cases published to date. We report a 56-year-old patient with silent sinus syndrome in whom vertical diplopia was treated with prisms showing that conservative treatment alone may, in mild cases, be an effective alternative to reconstructive surgery.

Diplopia↗
PubMedDate not supplied

Anterior lamellar keratoplasty with a microkeratome: a method for managing complications after refractive surgery.

PURPOSE: To demonstrate a technique of anterior lamellar keratoplasty with standardized and automated preparation of surface-parallel cuts in both donor and recipient appropriate for addressing several problems after laser in situ keratomileusis (LASIK) and photorefractive keratectomy (PRK). METHODS: We report a noncomparative series of ten eyes with complications after LASIK and PRK. Lamellar cuts were performed in donor and recipient eyes by means of an automated microkeratome. Lamellar grafts were fixed by only four single sutures. In two eyes, a re-lift LASIK was performed after 6 months. RESULTS: Surgery was uneventful and visual acuity was improved in all eyes. Residual irregular astigmatism and refractive error were corrected in two eyes by means of excimer laser computer-assisted ablation and resulted in a further improvement of uncorrected and best spectacle-corrected visual acuity. CONCLUSIONS: Anterior lamellar keratoplasty with a microkeratome can be used for the management of certain complications of PRK and LASIK.

Adult↗
PubMedDate not supplied

Clinical photoablation with a 500-Hz scanning spot excimer laser.

PURPOSE: The aim of this study was to use a 500-Hz scanning spot laser (Concept500, WaveLight Laser Technologie AG, Erlangen, Germany) to investigate potential side effects that might be associated with the use of a high repetition rate laser platform. METHODS: Seven eyes were treated using a 500-Hz scanning spot laser for laser in situ keratomileusis (LASIK). The local frequency of the ablation was kept below 40 Hz to avoid local heating of corneal tissue. With the exception of the high repetition rate (500 Hz), all other laser parameters such as fluence, algorithm, ablation profile, and spot diameter were identical to a standard WaveLight Allegretto laser system. Patients were examined at 1 month and 1 year after initial treatment. Preoperative and postoperative examination included manifest sphere and cylinder, uncorrected and best spectacle-corrected visual acuity (BSCVA). RESULTS: All eyes were treated for myopia or myopic astigmatism. Five eyes received spherocylindrical and two eyes spherical ablation only. No adverse events correlated with the use of a high repetition rate laser system were observed during surgery or at any point during follow-up. All eyes maintained or had improved BSCVA at 12 months after treatment when compared to preoperative values. CONCLUSION: The use of an excimer laser with a maximal repetition rate of 500 Hz and a local repetition rate of less than 40 Hz was free of any specific side effect that might be associated with the use of such a high repetition rate.

Adult↗