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KERATOCONUSDR KHALED EL KHALED, MD, MRCOPHTH
SUBJECTS OF DISCUSSION FOR
ROUND TABLE
Introduction (clear definition of the disease)
Pathophysiology and Risk Factors (Genetic,
Environmental, etc.)
Diagnosis: slit lamp, clinical signs, topography, new
technologies (pentacam, ultrasound pachymetry) ..
Etc.
SUBJECTS OF DISCUSSION FOR
ROUND TABLE Clinical Signs; anatomical v-shape (pictures)
Topography in Diagnosis (early; moderate and advanced)
Spectacle correction (duration)
Contact lens (indications; types; duration; Rigid gas-permeable lenses)
Intrastromal corneal ring segments (FDA; indications; technics of surgery incision site; Segment type (mayorings..; number of rings.. Etc)
X-linking (FDA; indications; follow up)
ICRS + CXL {sameday} (then explantation of ICRS)
ICRS then PRK and CXL
Discussion: which to start; ideas
Topography-guided conductive keratoplasty (new procedure; indications.. etc)
Keratoplasty (PKP and DALK; indications; follow up)
PKP vs DALK; ideas
Keratoprosthesis (indications)
Boston 1 Keratoprosthesis vs repeated donor keratoplasty; ideas
Outcome; Conclusion and Message; Guidelines
Case reports and discussion
INTRODUCTION
ROUND HOT SPOT
OVAL HOT SPOT
SUPERIOR HOT SPOT
(SUPERIOR STEEP - SS)
INFERIOR HOT SPOT
(INFERIOR STEEP - IS)
IRREGULAR SHAPE
(STEEP AREAS ARE MIXED WITH FLAT AREAS)
SYMMETRIC BOWTIE
SYMMETRIC BOWTIEITH SKEWED
STEEPEST RADIAL AXIS INDEX
SB/SRAX. There is an angulation between segments’ axes. This angulation is
clinically significant when it is >22º
Asymmetric bowtie inferiorly Asymmetric bowtie superiorly
Asymmetric bowtie with Skewed Steepest Radial Axis Index
Claw pattern or the kissing birds patternButterfly
Junctional pattern Smiling face
Vortex pattern
AMSLER-KRUMEICH CLASSIfiCATIONStage Characteristics1-2-3-4
Stage 1
•Eccentric steepening Induced myopia and/or
astigmatism of ≤ 5.0 D
•K-reading ≤ 48.00 D
•Vogt's lines, typical topography
Stage 2
•Induced myopia and/or astigmatism between 5.00
and 8.00 D
•K-reading ≤ 53.00 D
•Pachymetry ≥ 400 µm
Stage 3
•Induced myopia and/or astigmatism between 8.01
and 10.00 D
•K-reading > 53.00 D
•Pachymetry 200 to 400 µm
Stage 4
•Refraction not measurable
•K-reading > 55.00 D
•Central scars
•Pachymetry ≤ 200 µm
Stage is determined if one of the characteristics applies.
Corneal thickness is the thinnest measured spot of the cornea.
1Krumeich JH, Kezirian GM (April 2009). "Circular keratotomy to reduce astigmatism and improve vision in stage I and II keratoconus". J. Refract. Surg. 25 (4): 357–65.
2Krumeich JH, Daniel J (August 1997). "Lebend-Epikeratophakie und Tiefe Lamelläre Keratoplastik zur Stadiengerechten chirurgischen Behandlung des Keratokonus (KK) I-III" [Live epikeratophakia and deep lamellar keratoplasty for I-III stage-specific surgical treatment of keratoconus]. Klin. Monbl. Augenheilkd. (in German) 211 (2): 94–100.
3Alió JL1, Shabayek MH. Corneal higher order aberrations: a method to grade keratoconus. J Refract Surg. 2006 Jun;22(6):539-45.
4Kératocõne classique et kératocône fruste; arguments unitaires.
Four map composite display (sagittal curvature, anterior and posterior elevation, and corneal thickness). This cornea shows a significant positive island of elevation
(ectasia) on the posterior cornea (right lower map) in spite of a normal anterior surface (upper right and left map)
Four map composite display (sagittal curvature, anterior and posterior elevation, and corneal thickness). This cornea shows a significant positive island of elevation
(ectasia) on the posterior cornea (right lower map) in spite of a normal anterior surface (upper right and left map). In this example, the posterior ectasia is significant
enough to cause a displacement of the corneal thinnest point (lower left)
Belin/Ambrosio enhanced ectasia display. The display shows abnormalities in all
major parameters except those for the anterior corneal surface. Because the
anterior surface is still within normal limits, the patient would have good
spectacle vision in the presence of (subclinical) keratoconus
Belin/Ambrosio enhanced ectasia display. The display depicts a case of moderately
advance keratoconus where all the analyzed parameters (anterior and posterior
elevation, Kmax, and pachymetric parameters) are highly abnormal
Composite map showing anterior curvature upper left, corneal thickness lower left, anterior elevation
upper right, and posterior elevation lower right. The axial curvature map incorrectly locates the "cone"
near the periphery, while both the elevation maps and pachymetric map correctly reveals this as a case of
inferior keratoconus
Corneal thickness map of a true case of pellucid marginal degeneration. The
pachymetric map opened up to a full 12 mm view is the best map to differentiate
true pellucid from inferior keratoconus, as true pellucid will show a clear band of
corneal thinning near the inferior limbus
EPIDEMIOLOGY
There are a wide range of prevalences reported in
the general population, ranging from 50 to 230 per
100,000.
There is no difference in incidence and prevalence
between genders1-3.
1. Krachmer JH, Feder RS, Belin MW. Keratoconus and related noninflammatory corneal thinning disorders. Surv Ophthalmol 1984; 28:293.
2. Kennedy RH, Bourne WM, Dyer JA. A 48-year clinical and epidemiologic study of keratoconus. Am J Ophthalmol 1986; 101:267.
3. Rabinowitz YS. Keratoconus. Surv Ophthalmol 1998; 42:297.
RISK FACTORS
Systemic disorders
Environment
Eye-rubbing1
Contact lens use
Family history: This disorder has weak penetrance
and significant variability of expression.
1. Sugar J, Macsai MS. What causes keratoconus? Cornea 2012; 31:716.
GENETIC FACTOR
GENETIC FACTOR
GENETIC FACTOR
PATHOPHYSIOLOGY
Keratoconus is a noninflammatory disorder of the
cornea of unknown etiology.
Keratoconic corneas have a decrease in the content
of collagen compared with normal corneas.
PATHOPHYSIOLOGY
CLINICAL FEATURES
Asymmetric visual complaints
Difficulty with visual correction
Munson's sign
Corneal hydrops
MUNSON'S SIGN
CORNEAL HYDROPS
DIAGNOSIS
Difficulty correcting a patient’s vision to 20/20
visual acuity
Fleisher ring
Vogt striae
Central and inferior paracentral corneal thinning
Corneal scarring
FLEISHER RING
VOGT STRIAE
CORNEAL SCARRING
OPHTHALMIC TECHNIQUES
Retinoscopy: Scissoring reflex: early sign
Keratometry
Corneal topography
RETINOSCOPY: SCISSORING
REFLEX: EARLY SIGN
KERATOMETRY
CORNEAL TOPOGRAPHY
DIAGNOSIS
DIAGNOSIS
MANAGEMENT
Spectacle correction
Contact lens: Rigid gas-permeable lenses
Surgical treatments
Intrastromal corneal ring segments
Corneal collagen cross-linking
Keratoplasty
SPECTACLE CORRECTION
CONTACT LENS
INTRASTROMAL CORNEAL RING
SEGMENTS
Approved by the US Food and Drug Administration
(FDA) in 2004 for the management of Keratoconus.
Thin, semi-circular plastic inserts are implanted into
the mid-corneal layers to flatten the cornea.
INTRASTROMAL CORNEAL RING
SEGMENTS
INTRASTROMAL CORNEAL RING
SEGMENTS
INTRASTROMAL CORNEAL RING
SEGMENTS
INTRASTROMAL CORNEAL RING
SEGMENTS
INTRASTROMAL CORNEAL RING
SEGMENTS
CORNEAL COLLAGEN CROSS-
LINKING
CORNEAL COLLAGEN CROSS-
LINKING
Corneal collagen cross-linking using riboflavin and
UV received FDA approval on April 18, 2016.
CORNEAL COLLAGEN CROSS-
LINKING
CORNEAL COLLAGEN CROSS-
LINKING
CORNEAL COLLAGEN CROSS-
LINKING
CORNEAL COLLAGEN CROSS-
LINKING
CORNEAL COLLAGEN CROSS-
LINKING
CORNEAL COLLAGEN CROSS-
LINKING
CORNEAL COLLAGEN CROSS-
LINKING
INTRASTROMAL CORNEAL RING
SEGMENTS
CORNEAL COLLAGEN CROSS-
LINKING
TOPOGRAPHY-GUIDED
CONDUCTIVE KERATOPLASTY
TOPOGRAPHY-GUIDED
CONDUCTIVE KERATOPLASTY
KERATOPLASTY (CORNEAL
TRANSPLANTATION)
The procedure of choice when contact lenses are no longer helpful
Approximately 10 to 15 percent of patients with keratoconus will require Keratoplasty
Penetrating keratoplasty (full thickness corneal transplant) is the most commonly used procedure1-2.
Deep anterior lamellar keratoplasty (partial thickness corneal transplant) is another option
This procedure has a success rate of greater than 90 percent in patients with keratoconus3.
1. Gordon MO, Steger-May K, Szczotka-Flynn L, et al. Baseline factors predictive of incident penetrating keratoplasty in keratoconus. Am J Ophthalmol 2006; 142:923.
2. Keane M, Coster D, Ziaei M, Williams K. Deep anterior lamellar keratoplasty versus penetrating keratoplasty for treating keratoconus. Cochrane Database Syst Rev
2014; 7:CD009700.
3. Sharif KW, Casey TA. Penetrating keratoplasty for keratoconus: complications and long-term success. Br J Ophthalmol 1991; 75:142.
PENETRATING KERATOPLASTY
PKP
DEEP ANTERIOR LAMELLAR
KERATOPLASTY DALK
KERATOPLASTY (CORNEAL
TRANSPLANTATION)
KERATOPLASTY (CORNEAL
TRANSPLANTATION)
KERATOPLASTY (CORNEAL
TRANSPLANTATION)
KERATOPLASTY (CORNEAL
TRANSPLANTATION)
KERATOPLASTY (CORNEAL
TRANSPLANTATION)
KERATOPLASTY (CORNEAL
TRANSPLANTATION)
KERATOPLASTY (CORNEAL
TRANSPLANTATION)
KERATOPROSTHESIS
KERATOPROSTHESIS
KERATOPROSTHESIS
KERATOPROSTHESIS
KERATOPROSTHESIS
OUTCOME
CONCLUSION During early stages, vision can be corrected with eyeglasses.
As the condition progresses, rigid contacts may need to be worn so that light entering the eye is refracted evenly and vision is not distorted.
You should also refrain from rubbing your eyes, as this can aggravate the thin corneal tissue and make symptoms worse.
Keratoconus can also be treated with Intacs, Intacs are FDA approved.
Another treatment option for keratoconus that is not FDA approved is collagen cross-linking.
When good vision is no longer possible with other treatments, a corneal transplant may be recommended.
Another type of cornea transplant that is becoming more popular as a treatment for keratoconus is called DALK, or Deep Anterior Lamellar Keratoplasty.
Artificial cornea can be a solution after many rejections.
NICE GUIDELINE
NICE GUIDELINE
NICE GUIDELINE
THANK YOU