Faculty Bibliography

PURPOSE/OBJECTIVE: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/METHODS: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.

BACKGROUND:Nomograms are efficient tools to improve the predictability of refractive procedures by using statistical methods to analyze pre- and postoperative refractive data. The purpose of this work was to analyze the clinical relevance and limitations of nomograms in a case series. METHODS:Computer simulations based on the known unpredictability for refractive outcomes were performed for three different distribution functions of the preoperative refractions. In addition, the clinical applicability was investigated in three different cohorts that underwent laser in situ keratomileusis (LASIK). RESULTS:The use of individual nomograms significantly improves the predictability of the refractive outcome. However, theoretical investigation demonstrates that a homogeneous data distribution within cohorts is a key factor for predictable nomogram calculations. Outliers within the cohorts are not integrated into the nomogram calculation due to the mathematical model used. CONCLUSIONS:Nomograms are helpful for improving refractive outcomes. However, they are currently limited to approximately 90% within +/-0.5 D.

Although of benign nature and slowly progressive, paranasal sinus mucoceles may, depending on their localization, cause a multitude of ophthalmological symptoms due to compression and displacement of adjacent tissue. Here we report the unusual case of a patient suffering from a progressively growing giant mucocele that developed years after ENT surgery and that was neglected for almost 2 decades despite massive symptoms. This case report demonstrates the importance of including mucoceles of the paranasal sinuses into the differential diagnosis of unilateral or bilateral proptosis.

The predictability and quality of results in corneal refractive laser surgery are determined by a number of factors. Here, the calculation and choice of the ablation profile represent central elements. Our growing knowledge about the physical and optical properties of the eye in recent years has led to the development of different strategies in the generation of ablation profiles. This review describes the currently used ablation profiles with their advantages and disadvantages and provides an outlook on future methods for the calculation of ablation profiles.

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.

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.

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/CONCLUSIONS: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.

PURPOSE/OBJECTIVE:Propagation of light through the optical pathway within the eye can lead to a deformation of the wave front that might affect objective but also subjective refraction depending on pupil size. The aim of this study was to investigate the change in wave front refraction that is calculated on the basis of second order Zernike polynomials when varying the pupil size from 6 mm to 3 mm. The change was correlated with the amount of fourth and sixth order spherical aberration and fourth and sixth order astigmatism. METHODS:Wave front aberrations were measured in 130 eyes by means of a Tscherning wave front sensor at a pupil size of 6 mm. Wave front aberrations in terms of Zernike coefficients up to sixth order were approximated for 6 mm and 3 mm pupil size. The wave front refraction was calculated based on the second order Zernike coefficients for both pupil diameters. Resulting differences in wave front refraction (sphere or cylinder) due to the change in pupil size were correlated with the initial higher order aberrations determined for the 6.0 mm pupil by means of a linear regression (Spearman rank correlation coefficient). RESULTS:The correlation between the change in sphere and cylinder on one hand and the spherical aberration and higher order astigmatism on the other hand was found to be highly significant (p<0.001), with a correlation coefficient of R = 0.96 for sphere and R = 0.85 for cylinder. CONCLUSIONS:Calculating the wave front refraction on the basis of second order Zernike polynomials is plagued with the influence of the higher order aberration preexisting in the individual eye. This is one reason why this method does not represent precisely enough subjective refraction. Other methods that calculate the refraction based on wave front measurement independent from the pupil size should be established in the ophthalmic community.

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.