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Anatomic, Aberrometric , and Biomechanical Characteristics in Patients with Marfan Syndrome. Manuel Alejandro Garza León MD The author have no financial interest in the subject matter of this poster. Instituto para Preservación de la Visión. [email protected]. Introduction. - PowerPoint PPT Presentation
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ANATOMIC, ABERROMETRIC, AND BIOMECHANICAL CHARACTERISTICS IN PATIENTS WITH MARFAN SYNDROME
Instituto para Preservación de la Visióndr.manuel.garza@gmai
l.com
Manuel Alejandro Garza León MD
The author have no financial interest in the subject matter of this
poster.
Introduction Marfan syndrome (MFS) is an autosomal
dominant disorder of connective tissues, with an incidence of 1:10,000.
The systems affected are the skeletal, cardiovascular, and pulmonary systems, skin and ocular system.
According to the Gent classification, the ophthalmologic major criterion is ectopia lentis.
There are also 3 minor ophthalmologic criteria Abnormally flat cornea Increased axial length of the globe Hypoplastic iris or ciliary muscle dysfunction.
Purpose To report the anatomical, optical and
biomechanical corneal characteristics in patients with Marfan Syndrome Anatomical
Mean keratometry Central pachimetry
Optical Corneal aberrations represented by zernike
polynomials Biomechanical
Corneal hysteresis Corneal resistance factor
Methods Prospective, transversal and observational study of
patients with confirmed diagnosis of Marfan Syndrome without history of corneal trauma, infection, disease or surgery, Glaucoma or Diabetes
The anatomical and aberrometrical characteristics was measured with Rotating Scheimpflug Camera (Pentacam, Oculus) The readings were taken as described in the instructions
guide in automatic release mode. Only scans registering as ‘‘OK’’ on the instrument’s
‘‘Examination Quality Specification’’ were used for analysis.
The biomechanical characteristics was measured with the Ocular Response Analyzer (ORA, Reichert). The measures was made 4 times and represented by his
average. All the studies was made by the same person.
Results Demographic information
mean age was 24 ± 10.79 years (range, 11-39)
Results Iris and lens characteristics
Iridodonesis 80%Phacodonesis 100% *
Subluxation of lens 100% *Subluxation without
pharmacological pupillary dilation 88.24%(15/17)
Localization of the subluxationSuperonasal 41.2% (7/17)Inferior 35.29% (6/17)Superotemporal
23.53% (4/17)* 3 eyes of 2 patients was aphakic because a spontaneous posterior lens dislocation
Results Corneal characteristics
Anatomical Mean Sim K 40.49±1.54 D (38.7 to 42.7 D)80% of eyes has less than 42 DFlat Sim K 39.45±1.55 D (37.7-41.9 D)Step Sim K 41.52±1,62 D (39.2-43.7)Central corneal thickness 562±37.23 µm (506-626 µm)
Results Corneal characteristics
Aberrometric Trefoil 0.00085±0.00029 µm (0.00064-0.00106 µm) Coma 0.00197±0.00016 µm (0.00186-0.00209 µm)Tetrafoil 0.00068±0.0004 µm(0.00037-0.00098 µm)aberration coefficient * 1.55±0.37 (1.1-2.5) * Coefficient that the Oculus Pentacam system calculates from the Zernike analysis with normal values are less than 1
BiomechanicalCorneal Hysteresis 9.13±1.49 mmHg(7.1-12 mmHg) Corneal Resistence Factor 9.09±2.41 mmHg (4.8-13.6 mmHg)
Discussion Our number of aphakic eyes (15%) its more
than the reported previously (2--3% of eyes) * maybe because our patients became from an
exclusive ophthalmic practice. Of the other 17 patients, all had phacodonesis
and subluxation of the lens this results are similar to the 86% reported by Sultan y coworkers¥.
80% of patients with mean keratometry less than 42 D similar to the reported by Heur and associated (74.5%)
* Nemet AY, Assia EI, Apple DJ, Barequet IS. Surv Ophthalmol. 2006;51:561-75¥ Sultan G, Baudouin C, Auzerie O, et al. Invest Ophthalmol Vis Sci. 2002;43:1757-64.Heur M, Costin B, Crowe S,et al. Am J Ophthalmol. 2008;145:997-1001
Discussion Central corneal thickness 562±37.23
µm(range, 506 - 626 µm) similar to reported by Heur and collegues with US pachymetry (CCT of 543.5 ±37.3µm) but differs with Sultan y coworkers who reported a significant decrease in pachymetry in MFS patients (502 ± 41.9 µm) compared with the controlled group with Orbscan pachymetry Racial differences in CCC could explain our
difference other possible explications are the different equipments used.
Sultan G, Baudouin C, Auzerie O, et al. Invest Ophthalmol Vis Sci. 2002;43:1757-64.Heur M, Costin B, Crowe S,et al. Am J Ophthalmol. 2008;145:997-1001
Discussion Optical corneal characteristics measured as
aberration coefficients, All the patients had a patological aberration coefficient values 1.55±0.37 (range, 1.1-2.5) Normal Value less than 1. In vivo confocal microscopy findings reported by the
team of Sultan and Iordaniou found an alteration of the extracellular matrix in the stroma with an abnormal Z-scan profiles with an increased stromal back scattering of light and a brightly hyperreflective lines of extracellular matrix could indicate the presence of abnormal fibrillin in abundance in the stroma or a different spectrum of reflectivity of the abnormal fibrillinin.
All this changes may produce a histological irregularity manifested as corneal aberrations
Sultan G, Baudouin C, Auzerie O, et al. Invest Ophthalmol Vis Sci. 2002;43:1757-64.Iordanidou V, Sultan G, Boileau C, et al. Cornea. 2007;26:787-92
Conclusions The biomechanical properties of corneas of
Marfan patients in our group are within normal values reported in the literature, the Corneal Hysteresis was 9.13±1.49 mmHg (range, 7.1-12) and the corneal resistance factor 9.09±2.41 mmHg (range, 4.8-13.6).
In conclusion In our studied group, the corneas of Marfan
Syndrome patients presents a flat corneas with a normal pachymetry and biomechanical properties but with a abnormal aberration coefficient values.
del Buey MA, Cristóbal JA, Ascaso FJ, et al. Invest Ophthalmol Vis Sci. 2009;50:3199-202Ortiz D, Piñero D, Shabayek MH, et al. J Cataract Refract Surg. 2007;33:1371-5