intacs nomogram
DESCRIPTION
INTACS 7mm lik optik alana implante edilir. Görmüş olduğunuz slayt ring seçiminde kullanacağınız nomogramdır.TRANSCRIPT
C OM P R E H E N S I V E N OM O G R AM
A N D P R E -‐ S U R G I C A L P L A N N I N G G U I D EUPDATED
February 1, 2011
A D D I T I O N T E C H N O L O G Y I N C .The Leader In Corneal Sc ience & Implant Technology
950 Lee Street , Suite 210,Des Plaines, IL 60015 • telephone: (847) 297-8419 • fax: (847) 297-8678
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w w w . A d d i t i o n T e c h n o l o g y . c o m
I n t e r n a t i o n a l U s e O n l y
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AddiEon Technology in collaboraEon with highly experienced Intacs surgeons have analyzed thousands of cases over a mulE-‐year period to provide a “best pracEces” approach to pre-‐surgical planning.
The goal of Intacs is to restore functional vision by re-shaping the cornea from within the stromal layers thus changing the optical properties of the cornea.
The following nomogram, pearls and pre-‐surgical plan-‐ning steps have been created to assist you with your ini-‐Eal cases. AddiEonal pearls and Eps are available via your on-‐line account at www.addiEontechnology.com. Contact your representaEve for further assistance with pre-‐surgical planning and case review.
Keratoconus Nomogram -‐ IntacsChoose symmetric or asymmetric segments using the following guidelines:
Use the symmetric chart when the cone on the posterior float is within the central 3-‐5 mm opEcal zone and the sphere power is greater than the cylinder power on the manifest re-‐fracEon notated in posiEve cylinder.
Use the asymmetric chart when the cone on the posterior float is located outside the 3 mm geometric center and the cylinder power is greater than the sphere power on the manifest refracEon notated in posiEve cylinder.
When the sphere power is equal to or similar to the cylinder power on the manifest refrac-‐Eon notated in posiEve cylinder, use the symmetric chart however, consider asymmetric chart when cone is de-‐centered or superior-‐nasal periphery shows considerable flaWening compared to inferior-‐temporal periphery. See Verifier 3.
SYMMETRICSYMMETRICSYMMETRIC
Sphere Power Inferior Intacs Superior Intacs-‐0.00 to -‐1.00 D 0.210 mm 0.210 mm-‐1.00 to -‐1.75 D 0.250 mm 0.250 mm-‐2.00 to -‐2.75 D 0.300 mm 0.300 mm-‐3.00 to -‐3.75 D 0.350 mm 0.350 mm-‐4.00 to -‐4.75 D 0.400 mm 0.400 mmOver -‐5.00 D 0.450 mm 0.450 mm
ASYMMETRICASYMMETRICASYMMETRIC
Cylinder Power Inferior Intacs Superior Intacs2.00 to 3.00 .350mm .210mm3.00 to 4.00 .400mm .210mm
4.00 and higher .450mm .210mm
Quick Summary:
Step 1: View corneal topogra-‐phy and manifest refracEon.
Step 2: Verify steep meridian for incision locaEon.
Step 3: Select Intacs segments using nomogram on this page.
Intacs® Pre-‐Surgical Planning Guide & Comprehensive Nomogram
AddiEon Technology, Inc. -‐ © 2011 AddiEon Technology, Inc. All Rights Reserved -‐ Intacs® -‐ Plus Cylinder NotaEon
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Myopia Nomogram -‐ Intacs
SYMMETRICSYMMETRICSYMMETRIC
Spherical Power Inferior Intacs Superior Intacs
-‐0.00 to -‐0.75 D 0.210 mm 0.210 mm
-‐0.75 to -‐1.00 D 0.230 mm 0.230 mm
-‐1.00 to -‐1.30 D 0.250 mm 0.250 mm
-‐1.30 to -‐1.70 D 0.275 mm 0.275 mm
-‐1.70 to -‐2.00 D 0.300 mm 0.300 mm
-‐2.00 to -‐2.30 D 0.325 mm 0.325 mm
-‐2.30 to -‐2.70 D 0.350 mm 0.350 mm
-‐2.70 to -‐3.00 D 0.375 mm 0.375 mm
-‐3.00 to -‐3.40 D 0.400 mm 0.400 mm
-‐3.40 to -‐3.70 D 0.425 mm 0.425 mm
Over -‐4.00 D 0.450 mm 0.450 mm
Intacs® Pre-‐Surgical Planning Guide & Comprehensive Nomogram
AddiEon Technology, Inc. -‐ © 2011 AddiEon Technology, Inc. All Rights Reserved -‐ Intacs® -‐ Plus Cylinder NotaEon
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Intacs Pre-‐Surgical Planning Guide Step 1: Measurements & Materials
Ideal measurements and materials:
• Manifest refracEon• BCVA / UCVA• Corneal topography
• Axial • Posterior Float• Keratometric (Numeric Overlay)• Pachymetry (at least 4-‐6 locaEons)
• Min K & Max K values (on topography)
Other measurements to consider notaEng and topography views include:
• Incision locaEon and depth (measured and actual)• Contact lens tolerance• Contact lenses prescribed (pre & post operaEve) • Endothelial cell counts are not necessary but may be helpful• Numeric Overlay• RefracEve Power (Front)• Mean Power Keratometric
Defini>ons:
Steep Meridian: IdenEfied as the manifest refracEon axis in posiEve cylinder notaEon or the topographical Max K axis.
Flat Meridian: IdenEfied as the manifest refracEon axis in minus cylinder notaEon or the topographical Min K axis.
Step 2: Incision Placement & Cone Loca>on
Verify steep meridian for incision placement. The manifest refracEon axis notated in posiEve cylinder and the Max K axis on topography should match. If they vary by ± 15°, see Verifier 2 for more details. The “red” line in image below idenEfies the steep meridian.
Using a posterior view, idenEfy if the cone is centered or de-‐centered by using the 3 mm, 5 mm and 7 mm markings on topography. Draw a line across the cornea in the direcEon of cone displacement (blue line in image on lel). In most cases, the incision is placed superior-‐temporal on the steep meridian. See Verifier 1 below for more details.
Step 3: Segment Selec>on -‐ See nomogram on page 1
The keratoconic cornea has unique biomechanical properEes and asymmetric irregulariEes whereby a number of measurements may require verificaGon prior to surgery. The supporEng pages outline key verifiers helpful in enhancing results.
Intacs® Pre-‐Surgical Planning Guide & Comprehensive Nomogram
AddiEon Technology, Inc. -‐ © 2011 AddiEon Technology, Inc. All Rights Reserved -‐ Intacs® -‐ Plus Cylinder NotaEon
3
Verifiers For Pre-‐Surgical Planning The refracEve power of the cornea is based on the curvature and symmetry of the corneal sur-‐face. In keratoconus, the corneal surface is irregular resulEng in compound / irregular asEgma-‐Esm. Each keratoconus case is unique with various irregular properEes that can be evaluated using diagnosEc data that has been idenEfied:
• With the Manifest RefracEon• From the BCVA / UCVA findings• Across the anterior surface of the cornea (keratometric values)• Within the stromal layers (pachymetry values)• From the corneal back surface (posterior float)
Verifier 1: Posterior Float -‐ Centered or De-‐centered
Centered cones typically call for symmetric segments whereas de-‐centered cones call for asym-‐metric segments. Using the posterior view showing cone displacement helps with choosing symmetric or asymmetric segments. EvaluaEng cone locaEon and displacement also aids in verifying the proposed incision locaEon & Intacs placement.
To idenEfy the proposed incision locaEon, draw a “blue” line across the center of the posterior view in the direcEon the cone is displaced. Then, draw a “red” line perpendicular to the “blue” line making a plus sign or “X” over the posterior view (See Figure 1). The blue line represents the flat meridian (where the Intacs will be placed) and the red line represents the steep merid-‐ian (where the incision will be placed). NoEce the Max K axis and manifest refracEon axis in posiEve cylinder notaEon should match.
Match Mis-‐Match
Intacs® Pre-‐Surgical Planning Guide & Comprehensive Nomogram
AddiEon Technology, Inc. -‐ © 2011 AddiEon Technology, Inc. All Rights Reserved -‐ Intacs® -‐ Plus Cylinder NotaEon
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Verifier 2: Manifest Refrac>on vs Steep K (Max K) Axis & BCVA
Compare the axis in the manifest refracEon notated in posiEve cyl-‐inder to the Max K axis on topography. Is the BCVA 20/50 or beWer? In an ideal case, the Max K axis and manifest refracEon axis in posi-‐Eve cylinder notaEon should match within 15ᴼ of each other and be located along the steep meridian idenEfied in Verifier 1.
Each case is unique. The BCVA provides us informaEon on how well the paEent “sees” with their current refracEon. When the BCVA is worse than 20/50, and/or there is more than a 15° difference between the BCVA and the Max K axis, re-‐take the manifest refracEon and/or topog-‐raphy to confirm they match or conEnue to look at the verifiers in this guide.
Verifier 3: With-‐The-‐Rule As>gma>sm vs Against-‐The-‐Rule As>gma>sm & Corneal Imbalance
Color paWerns and K values on the keratometric view provide important informaEon for evaluat-‐ing corneal refracEve imbalance. First, idenEfy the steep and flat areas of the map by visual ob-‐servaEon of the map colors. Is there a clear dis-‐EncEon of blue (superiorly) and red (inferiorly)? Is the map mostly red? Does the overall paWern look like an hourglass? PMD (Crab claw)? Is the cone on the posterior view centered or de-‐centered?
Next, evaluate the K values on the keratometric view or use a numeric overlay view and evaluate K values across all areas of the map. If the map clearly shows a split of blue and red color in the 6 -‐ 7 mm diameter, idenEfy the steepest K values (circle them) and the flaWest K values (circle them). Then, idenEfy the K values that are most similar on opposite sides of each other (See fig-‐ure 2). In these cases, asymmetric segments are ideal unless the cone is centered on the posterior float (See figures 2 and 3).
If the map looks like a crab claw (PMD), noEce how the flaWest peripheral K readings are oppo-‐site the steepest peripheral K readings along the the flat meridian (See figure’s 2 & 3). In PMD to-‐pographical paWerns, the flaWest peripheral K reading is usually significantly less than the op-‐posing steep peripheral K reading (<41K). Also, noEce the two similar peripheral K readings op-‐posite each other located along the steep merid-‐ian circled in white in figure’s 2 & 3.
20/50Intacs® Pre-‐Surgical Planning Guide & Comprehensive Nomogram
AddiEon Technology, Inc. -‐ © 2011 AddiEon Technology, Inc. All Rights Reserved -‐ Intacs® -‐ Plus Cylinder NotaEon
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Figure 2
Figure 3
OpEcally, the asEgmaEsm in highly asym-‐metric PMD cases is typically against-‐the-‐rule and requires balancing inferior and su-‐perior to the steep meridian and can some-‐Emes be located along the oblique axis.
If the map looks like an incomplete crab claw (PMD-‐Like) or a highly irregular hour glass or snowman with a very small crooked head (see figure 4), noEce how the flaWest peripheral K readings are 90° away from the steep meridian. The asEgmaEsm in these cases is mostly oblique. Symmetric seg-‐ments are commonly recommended how-‐ever, asymmetric segments may be used depending on the posterior cone displace-‐ment, the amount of cylinder and how flat the superior side of the steep meridian shows.
If the map looks like an hourglass (see figure 5), noEce how the peripheral K readings are fairly similar and the two similar peripheral K readings opposite each other are located along the flat meridian. The asEgmaEsm in these cases is typically with-‐the-‐rule and requires balancing nasal and temporal to the steep meridian. The steep meridian axis may vary ± 15° and may someEmes be lo-‐cated along the oblique axis. Symmetric segments are commonly used.
Verifier 4: Pachymetry
IdenEfying the peripheral pachymetry can be an indicator for corneal health and can be a characterisEc in detecEng corneal ecta-‐sia 1. Thin peripheral readings can help verify cone displacement in some cases and can assist in verifying incision locaEon and placement.
1 R. Ambrósio Jr, Poster ASCRS 2006
Note: Determining segment selecGon is dependent upon the surgeons decision where to im-‐prove sphere and/or cylinder correcGon to best achieve a biomechanical and refracGve corneal balance.
Intacs® Pre-‐Surgical Planning Guide & Comprehensive Nomogram
AddiEon Technology, Inc. -‐ © 2011 AddiEon Technology, Inc. All Rights Reserved -‐ Intacs® -‐ Plus Cylinder NotaEon
6
Figure 4
Figure 5
Corneal Topography Views & Various Cone Examples
-‐5.75 +3.75 x 123 -‐11.25 +3.50 x 47
-‐9.75 +2.25 x 56 -‐3.25 +5.75 x 162
-‐3.75 +5.50 x 30-‐8.75 +2.00 x 107
-‐5.25 +3.00 x 67 -‐4.50 +7.00 x 14
Intacs® Pre-‐Surgical Planning Guide & Comprehensive Nomogram
AddiEon Technology, Inc. -‐ © 2011 AddiEon Technology, Inc. All Rights Reserved -‐ Intacs® -‐ Plus Cylinder NotaEon
7
Intacs Guidelines & Pearls
General Guidelines & Pearls
• Incision depth should be a minimum of 70%.• Snug incision closure with 10.0 nylon suture. Maintain for up to 2 months.• Keep cornea hydrated during surgery.• PaEents with pupils greater than 7 mm may be predisposed to low light sensiEvity such
as glare and halos and should be appropriately advised.• Single segments are not recommended.• It may take 3 – 6 months for visual acuity to stabilize. • When creaEng a channel where the cornea is thinnest, slowly advance the dissector
threading into stroma. If any resistance or wave-‐like appearance is seen with corneal Essue, slow or stop dissecEon/ inserEon unEl Essue adjusts.
• UElizing a disposable contact lens to manage spherical correcEon during the first 1 -‐ 6 months may aid in final contact lens success. Advise paEent of visual limitaEons due to no cylindrical correcEon with disposables.
• Contact lens fixng can start as early as 6 weeks with the understanding that vision may fluctuate for up to 3 – 6 months before stabilizing.
• Vision conEnues to improve over Eme. 3,4
Pa>ent Acceptance Criteria
• PKP a consideraEon• Diagnosis indicates ectaEc condiEon• Contact lens intolerant (Clear central cornea)• Pachymetry at least 450μ at incision locaEon
Femtosecond Guidelines
• Inner diameter sexng: 6.8 / Outer diameter sexng: 7.8• If channels too Eght, increase outer diameter sexng by 0.1 mm unEl desired width is
achieved.
Your AddiEon Technology representaEve is a valuable resource for updates, addiEonal pracEce informaEon, training and guidance. More informaEon can also be found by joining the ATI Phy-‐sician Network at www.AddiEonTechnology.com/eye.
3 Long-‐term Follow-‐up of Intacs in Keratoconus, George D. Kymionis, MD, PHD, et al, Am J Ophthalmol. 2007 Feb;143(2):236-‐244. Epub 2006 Nov 30.4 My First Intacs Case – 10 Year Stability, Prof. Joseph Colin, Presented at the American Academy of Ophthalmology, 2007.
Cover image courtesy of David Schanzlin, M.D.
Intacs® Pre-‐Surgical Planning Guide & Comprehensive Nomogram
AddiEon Technology, Inc. -‐ © 2011 AddiEon Technology, Inc. All Rights Reserved -‐ Intacs® -‐ Plus Cylinder NotaEon
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The Worldwide Leader In Corneal Science & Implant Technology
950 Lee Street, Suite 210Des Plaines, IL 60016Phone: (847) 297-‐8419Fax: (847) 297-‐8678
AddiEon Technology would like to thank all the Intacs surgeons worldwide for their conEnued contribuEons to the Intacs technology and nomogram. The Intacs Nomogram is based on Intacs technology -‐ the
only ICRS in the world having undergone clinical trials. ReproducEon of the nomogram for use with any other technology is prohibited.Intacs® and Intacs® SK are registered trademarks of AddiEon Technology Inc.
© 2011 AddiEon Technology, Inc. All Rights Reserved.
www.AddiEonTechnology.com
Intacs® Pre-‐Surgical Planning Guide & Comprehensive Nomogram
AddiEon Technology, Inc. -‐ © 2011 AddiEon Technology, Inc. All Rights Reserved -‐ Intacs® -‐ Plus Cylinder NotaEon
9