Role of Optical Coherence Tomography on Corneal Surface Laser Ablation

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. Which of the current imaging instruments is a better choice depends on the specific application. in laser in situ keratomileusis (LASIK) and in excimer laser phototherapeutic keratectomy (PTK), OCT can be used to assess corneal characteristics and guide treatment decisions. OCT accurately measures central corneal thickness, evaluates the regularity of LASIK flaps, and quantifies flap and residual stromal bed thickness. When evaluating the ablation depth accuracy by subtracting preoperative from postoperative measurements, OCT pachymetry correlates well with laser ablation settings. in addition, OCT can be used to provide precise information on the morphology and depth of corneal pathologic abnormalities, such as corneal degenerations, dystrophies, and opacities, correlating with histopathologic findings.Cleveland Clin Fdn, Cole Eye Inst, Cleveland, OH 44114 USAAltino Ventura Fdn, Dept Ophthalmol, Recife, PE, BrazilUniv Fed Rio de Janeiro, Dept Ophthalmol, Rio de Janeiro, RJ, BrazilUniversidade Federal de São Paulo, Dept Ophthalmol, São Paulo, SP, BrazilUniversidade Federal de São Paulo, Dept Ophthalmol, São Paulo, SP, BrazilWeb of Scienc

Ocular findings in patients with systemic sclerosis

OBJECTIVE: To evaluate the frequency and characteristics of ocular manifestations in outpatients with systemic sclerosis. METHODS: In this cross-sectional study, 45 patients with systemic sclerosis were enrolled. Data regarding demographics, disease duration and subtype, age at diagnosis, nailfold capillaroscopic pattern and autoantibody profile were collected, and a full ophthalmic examination was conducted. Parametric (Student's t-test) and nonparametric (Mann-Whitney U test) tests were used to compare continuous variables. Fisher's exact test was used to compare categorical data. P values < 0.05 were considered significant. RESULTS: Twenty-three subjects (51.1%) had eyelid skin changes; 22 (48.9%) had keratoconjunctivitis sicca, 19 (42.2%) had cataracts, 13 (28.9%) had retinal microvascular abnormalities and 6 (13.3%) had glaucoma. Eyelid skin changes were more frequent in patients with the diffuse subtype of systemic sclerosis and were associated with a younger age and an earlier age at diagnosis. Cataracts were presumed to be age-related and secondary to corticosteroid treatment. There was no association between demographic, clinical or serological data and keratoconjunctivitis sicca. The retinal microvascular abnormalities were indistinguishable from those related to systemic hypertension and were associated with an older age and a severe capillaroscopic pattern. CONCLUSIONS: Eyelid skin abnormalities and keratoconjunctivitis sicca were the most common ocular findings related to systemic sclerosis. Some demographic and clinical data were associated with some ophthalmic features and not with others, showing that the ocular manifestations of systemic sclerosis are characterized by heterogeneity and reflect the differences in the implicated pathophysiological mechanisms

Modulation transfer function and optical quality after bilateral implantation of a+3.00 D versus a+4.00 D multifocal intraocular lens

PURPOSE: To determine whether the improvement in intermediate vision after bilateral implantation of an aspheric multifocal intraocular lens (IOL) with a +3.00 diopter (D) addition (add) occurs at the expense of optical quality compared with the previous model with a +4.00 D add. SETTING: Department of Ophthalmology, University of Sao Paulo, Sao Paulo, Brazil. DESIGN: Prospective randomized double-masked comparative clinical trial. METHODS: One year after bilateral implantation of Acrysof Restor SN6AD1 +3.00 D IOLs or Acrysof Restor SN6AD3 +4.00 D IOLs, optical quality was evaluated by analyzing the in vivo modulation transfer function (MTF) and point-spread function (expressed as Strehl ratio). The Strehl ratio and MTF curve with a 4.0 pupil and a 6.0 mm pupil were measured by dynamic retinoscopy aberrometry. The uncorrected and corrected distance visual acuities at 4 m, uncorrected and distance-corrected near visual acuities at 40 cm, and uncorrected and distance-corrected intermediate visual acuities at 50 cm, 60 cm, and 70 cm were measured. RESULTS: Both IOL groups comprised 40 eyes of 20 patients. One year postoperatively, there were no statistically significant between-group differences in the MTF or Strehl ratio with either pupil size. There were no statistically significant between-group differences in distance or near visual acuity. Intermediate visual acuity was significantly better in the +3.00 D IOL group. CONCLUSION: Results indicate that the improvement in intermediate vision in eyes with the aspheric multifocal +3.00 D add IOL occurred without decreasing optical quality over that with the previous version IOL with a +4.00 D add

Serum and plasma hormonal concentrations are sensitive to periods of intensity and volume of soccer training

Objectifs Évaluer les effets d’un programme d’entraînement de 12 semaines sur les concentrations hormonales et la performance physiologique des joueurs de football. Sujets et méthodes Dix-huit sujets ont été évalués au commencement (T1), au milieu (T2) et à la fin (T3) de la saison. Leur sang a été recueilli pour l’analyse du cortisol, testostérone, rapport testostérone/cortisol, épinéphrine et norépinéphrine. Les paramètres anaérobie lactique/alactique et le seuil anaérobie ont été utilisés comme mesures de performance physiologique. Résultats Tandis que les niveaux de cortisol étaient plus élevés en T2 et T3 comparés à ceux de T1 (p ≤ 0,05), les valeurs de testostérone et les rapports testostérone/cortisol étaient significativement moins élevés en T2 et T3 comparés à ceux de T1 (p ≤ 0,05). Les concentrations de norépinéphrine ont augmenté de T1 à T2 et T3 (p ≤ 0,05). En plus, alors qu’il y a eu une baisse significative des paramètres de la performance anaérobie alactique en T2 et T3 comparés à ceux de T1 (p ≤ 0,05), le seuil anaérobie s’est élevé en T2 et T3 comparé à T1 (p ≤ 0,05). En résumé, nous avons constaté que les niveaux de NE peuvent être utilisés comme marqueurs des variations de volume et intensité d’entraînement. En plus, les altérations dans les niveaux d’hormones sélectionnés dans cette étude n’ont pas été associées à des réponses négatives des performances physiologiques.Mots clés Cortisol; Testostérone; Testostérone/cortisol rapport; Catécholamines; Football

Prevalence of corneal astigmatism in cataract surgery candidates at a public hospital in Brazil

ABSTRACT Purpose: To assess the frequency of corneal astigmatism before cataract surgery in a Brazilian sample. Methods: This clinic-based cross-sectional study was conducted at the Bonsucesso Federal Hospital, Rio de Janeiro, Brazil. Charts of patients who underwent cataract surgery over a two-year period were retrospectively reviewed, and preoperative keratometric measurements were collected and analyzed. Results: A total of 1707 eyes of 1045 patients were enrolled. The corneal astigmatism was less than 1.0 D in 971 eyes (56.9%), 1.0-1.99 D in 496 eyes (29.1%), 2.0-2.99 D in 157 eyes (9.2%), and more than 3.0 D in 83 eyes (4.9%). The mean corneal astigmatism was 0.92 ± (SD) 0.96 D (range 0 - 10.25 D). Conclusion: Over 40% of the patients undergoing cataract surgery enrolled in this study had more than 1.0 D of corneal astigmatism and may benefit from the use of toric intraocular lenses. These data can be useful for planning to make this technology available for patients

Effect of soccer training on the running speed and the blood lactate concentration at the lactate minimum test

Tegtbur et al. [23] devised a new method able to estimate the intensity at maximal lactate steady state termed lactate minimum test. According to Billat et al. [7], no studies have yet been published on the affect of training on highest blood lactate concentration that can be maintained over time without continual blood lactate accumulation. Therefore, the aim of the present study was to verify the effect of soccer training on the running speed and the blood lactate concentration (BLC) at the lactate minimum test (Lac(min)). Thirteen Brazilian male professional soccer players, all members of the same team playing at National level, volunteered for this study. Measurements were carried out before (pre) and after (post) eight weeks of soccer training. The Lac(min) test was adapted to the procedures reported by Tegtbur et al. [23]. The running speed at the Lac(min) test was taken when the gradient of the line was zero. Differences in running speed and blood lactate concentration at the Lac(min) test before (pre) and after (post) the training program were evaluated by Student's paired t-test. The training program increased the running speed at the Lac(min) test (14.94 +/- 0.21 vs. 15.44 +/- 0.42* km(.)h(-1)) and the blood lactate concentration (5.11 +/- 2.31 vs. 6.93 +/- 1.33* mmol(.)L(-1)). The enhance in the blood lactate concentration may be explained by an increase in the lactate/H+ transport capacity of human skeletal muscle verified by other authors

Peripheral Sterile Corneal Ring Infiltrate After Riboflavin-UVA Collagen Cross-Linking in Keratoconus

Purpose: To present 7 cases of peripheral sterile corneal infiltrates that occurred after corneal cross-linking (CXL) for progressive keratectasia. Methods: Seven patients who had their progressive keratoconus documented underwent corneal deepithelization and subsequently CXL, which was performed with the application of 0.1% riboflavin with 20% dextran, and exposure to UVA light (370 nm, 2.9-3.1 mW/cm(2)) for 30 minutes. Results: Nearly a week after the procedure, the patients presented with peripheral stromal infiltrates. The ring-like infiltrates were superficial and were present at the 9.0-mm zone. Sterile infiltration was diagnosed. Patients were treated with topical corticosteroids, and complete resolution was achieved after a few weeks of treatment. Conclusions: We hypothesize that the phototoxic effect on the corneal stroma may be the main mechanism that triggers these infiltrates. Alternatively, alterations in antigenicity that occur in native proteins after CXL could result in patients recognizing the proteins as nonself and mounting immune responses

Collagen crosslinking with riboflavin and ultraviolet-A in eyes with pseudophakic bullous keratopathy

PURPOSE: To evaluate the safety and efficacy of corneal collagen crosslinking (CXL) in patients with painful pseudophakic bullous keratopathy (PBK). SETTING: University of Sao Paulo, Sao Paulo and Sadalla Amin Ghanem Eye Hospital, Joinville, Santa Catarina, Brazil. METHODS: This prospective study included consecutive eyes with PBK that had CXL. After a 9.0 mm epithelial removal, riboflavin 0.1% with dextran 20% was applied for 30 minutes followed by ultraviolet-A irradiation (370 nm, 3 mW/cm(2)). Therapeutic contact lenses were placed for 1 week. Corneal transparency, central corneal thickness (CCT), and ocular pain were assessed preoperatively and 1 and 6 months postoperatively. Statistical analysis was by paired t tests. RESULTS: Fourteen patients (14 eyes) with a mean age 71.14 years +/- 11.70 (SD) (range 53 to 89 years) were enrolled. Corneal transparency was better in all eyes 1 month after surgery. At 6 months, corneal transparency was similar to preoperative levels (P = .218). The mean CCT was 747 mu m preoperatively and 623 mu m at 1 month; the decrease was statistically significant (P<.001). At 6 months, the mean CCT increased to 710 mu m, still significantly thinner than preoperatively (P = .006). Pain scores at 6 months were not significantly different than preoperatively (P = .066). CONCLUSIONS: Corneal CXL significantly improved corneal transparency, corneal thickness, and ocular pain 1 month postoperatively. However, it did not seem to have a long-lasting effect in decreasing pain and maintaining corneal transparency in patients with PBK