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Fig. 4.9.7 Topographical changes after DALK. The map on the left is postoperative, the map in the middle is preoperative, and the map on the right is the difference map showing the change achieved by DALK
4.9.3Step3: Discussion
KC in the right eye is undoubtedly very severe, but because the cornea is still clear, DALK and not PKP is the choice. DALK was done to the right eye. Figures 4.9.5 and 4.9.6 are corneal topography 6 months after the operation. Figure 4.9.7 is the comparison map showing the big change in the cornea. It is clear that the shape of the cornea became relatively homogenous and there is with-the-rule astigmatism. Controlled releasing of sutures will compensate for this astigmatism.
KC in the left eye is also advanced but less than the right eye. Options for treatment are as follows:
1.CxL to stop the progression, but is contraindicated in this case because of the following reasons:
(a)Corneal thickness at the thinnest location is <400 m.
(b)Maximal K-reading is > 58 dpt carrying the risk of complications.
2.ICRs: The conditions for using the ICRs in this case are not completely suitable because of:
(a)Stress lines.
(b)High K-readings.
(c)Thin cornea.
(d)The case is still progressing.
3.On the other hand, ICR implantation was performed in the left eye for the following reasons:
(a)1.BSCVA and the difference between the UCVA and BSCVA is favorable.
(b)The cornea is still clear.
(c)The right eye needs an emergent DALK and the patient refused a future DALK for his left eye.
Figures 4.9.8 and 4.9.9 are corneal topography after implanting one inferior segment at the 5 mm circle. As shown in these figures, there is an overcorrection! This is clear in Fig. 4.9.10 which is a comparison between the preoperative and postoperative topography. The difference map on the right shows a very big change on the vertical axis, which is just opposite to
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Fig. 4.9.8 Corneal topography of the left eye after implanting one inferior segment on the 5 mm zone
Fig. 4.9.9 Anterior curvature map of the left eye after implanting one inferior segment on the 5 mm zone. When compared with the preoperative curvature map in Fig. 4.9.4, it is clear that the cone became central and a with-the-rule astigmatism was induced
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Fig. 4.9.10 Topographical changes after ICR implantation. The difference map shows the changes achieved by implanting the inferior segment. There is an overcorrection in corneal astigmatism as shown in red circles and on the difference map
on the right. A (the left column) is the post-op map; B (the middle column) is the pre-op map; and C (the right column) is the difference map representing the achieved results
the preoperative steepest axis (the horizontal axis); this is considered as an overcorrection although only one segment was used! The astigmatism shown within the red circles encounters the preoperative in the middle, the postoperative in the left, and the algebraic sum of both in the right map. When the algebraic sum is bigger than the preoperative astigmatism, it is mathematically an overcorrection. On the other hand, instead of improvement in K-readings, there was an increase in K1, K2, and K-max.
This unexpected and undesirable result can be attributed to the following factors:
1.Stress lines
2.Thin cornea
3.K-max > 60 dpt
4.Pattern 5 (author’s classification)
5.Grade 3 (Krumeich classification)
In conclusion, ICR implantation was not an appro-
priate choice. The patient underwent an explanation of the segment and a DALK was finally performed.
Index
A
Aberrations, 60, 70, 111, 129, 138 Acanthamoeba, 82 Against-the-rule, 19, 20, 27, 43
Age, 49, 56, 60, 76, 82, 85, 86, 88, 90, 96, 97, 100, 102, 108, 110, 112, 113, 117, 118, 124, 128, 129, 134, 136, 139, 142, 144
Analyzing step, 95–97, 100–101, 108–110, 112–113, 117–118, 128–129, 134–136, 138–139, 142–144
Aniridia, 1
Astigmatism, 1, 4, 19, 20, 22, 25, 27, 42, 43, 49, 59–63, 68, 73, 75–77, 81, 82, 86, 87, 96, 104, 105, 111, 124, 125, 127, 130, 132, 136, 137, 139–141, 145–148
Asymmetric bowtie (AB), 22, 27–29, 97, 113 Atopic disease, 68, 76
Atopy, 68, 76
Axis, 4, 27, 34–37, 43, 44, 50, 51, 56, 60–63, 68, 96, 100, 101, 103, 108, 112, 117, 124, 125, 128, 130, 134, 138–140, 142, 146, 148
B
Bell shape, 13, 45
Best corrected visual acuity, 60, 87, 88
Best fit sphere mode (BFS), 13, 17, 27, 42, 45, 47, 95, 113–115, 119, 120
Best fit toric ellipsoid mode (BFTE), 13, 27, 42, 45, 47, 113 Blue sclera, 1
Butterfly appearance, 43, 44
C
Central, 3, 4, 9, 13, 14, 17, 27, 34–37, 39, 43–46, 56, 60, 62, 64–68, 73, 74, 76, 81, 87, 88, 102–104, 113, 116, 119, 120, 122, 123, 125, 126, 129, 131, 137, 139, 141, 147
Claw pattern, 27, 30
Conductive keratoplasty (CK), 59, 60 Confocal microscopy, 7–8
Contact lens, 43, 53, 59–61, 68, 75, 76, 82, 83, 85, 88, 96, 100, 117, 128, 130, 139, 142
Contact lens wear, 43, 68, 76 Coordinate, 27, 45
Corneal biomechanics, 5 Corneal cross linking, 75–77 Corneal hysteresis, 5–7, 9, 41 Corneal melting, 53, 68, 76, 82 Corneal scaring, 2, 68, 76
Corneal topography, 3, 8–10, 13, 19, 27, 39, 41, 43, 48, 53, 68, 70, 85, 95–97, 100–102, 104, 105, 108–110, 112, 113, 117, 121, 125, 128–131, 134–136, 138, 140, 142–147
Corneal transparency, 86–88 Crescent lamellar keratoplasty, 87 Crystalline lens, 84, 85 Curvature based, 8–9
Cylinder, 81, 82, 87, 96, 100, 103, 108, 112, 117, 125, 128, 130, 134, 138, 139, 142
Cystoid macular edema, 84
D
Decompensation, 84, 85
Deep anterior lamellar keratoplasty (DALK), 61–62, 68, 87–90, 118, 124, 144–146, 148
Demarcation Line, 77, 81, 82 Descemets’ membrane, 2, 43 Diplopia, 84
Discussion step, 95, 101–107, 110–111, 116, 124–127, 129–133, 136–137, 139–141
Dislocation, 68, 84, 85 Distorted pupil, 84 Down syndrome, 68, 76
E
Eccentric, 34, 38, 136, 137, 139, 140 Ectasia, 6, 7, 9, 27, 42, 43, 56, 76, 82, 85, 87 Ectatic, 42, 62
Ectopia lentis, 1 Ehlers-Danlos syndrome, 10 Elasticity, 6, 86
Elevation, 9, 10, 13, 16, 17, 27, 41–43, 45, 56, 63, 66, 67, 74, 76, 79–81, 95, 101–104, 113–115, 118–120, 122–125, 133, 135, 140, 142, 144
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Elevation based, 9–10
Enantiomorphism, 19, 21
Endophthalmitis, 84, 85
Endothelial cells, 7, 60, 61, 83
Endothelial touch, 84
Endothelium, 2, 8, 61, 76, 77, 83, 84
Environment, 86
Epithelial cells, 2, 7, 68
Epithelium, 42, 43, 51, 75, 79, 82
Eye rubbing, 68, 76
F
Ferrara, 62
Flat, 4–6, 22, 25, 34, 38, 60, 61, 63, 87, 95, 101
Fleischer’s iron ring, 2
Floppy eyelid syndrome, 68, 76 Flourescein, 43, 44
Forme fruste keratoconus (FFKC), 27, 34–42, 76 Free radicals, 1
Furrow degeneration, 51, 57
G
Genetic, 1
Glare, 43, 63, 70, 84
Glaucoma, 61, 83, 85
Globus cones, 13, 15, 60, 73
H
Halos, 70, 84, 129, 130
Hemorrhage, 68, 84, 85
Hexagonality, 8
Hybrid, 59
Hydrops, 43, 48, 61, 68
Hydrops cornea, 2, 4, 68, 87, 89
Hyperopia, 60, 116, 130
Hypertension, 84
Hypotony, 84
I
Inferior, 1, 13, 24, 27, 28, 42–46, 49–53, 56, 70, 71, 73, 87, 97, 113, 118, 146–148
Inferior steep (IS), 22, 24, 34, 35 Inflammation, 85
Intacs, 62, 63
Intra corneal rings (ICRs), 13, 27, 34, 46, 59, 62–75, 83, 85–87, 89, 97, 98, 101–105, 110, 111, 113, 116, 118, 124, 126, 129–132, 136, 139–141, 144, 146, 148
Intra ocular refractive lenses (IORLs), 82–85, 87, 144 IOP, 83
IORLs. See Intra ocular refractive lenses (IORLs) Iris prolapse, 84
Irregular, 1, 4, 5, 7, 22, 25, 39, 41, 42, 59, 60, 70, 73, 111, 137, 140
Isolated island, 27
J
Junctional, 27, 31, 32, 142, 143
K
Keraring, 62
Keratoconus curve diagram, 43, 46, 54–56 Keratocytes, 7, 61, 82
Keratoectasia, 82 Keratoglobus, 49, 56, 57 Keratoscopy, 3–5
Kissing birds sign, 43, 45–49
K-max, 42, 62, 75, 76, 78, 82, 86–90, 97, 102–105, 110, 113, 117, 118, 125, 127, 129, 136, 139, 144, 148 K-readings, 27, 34, 64, 68, 73, 76–78, 83, 86, 89, 97, 98,
102, 103, 110, 111, 113, 116–118, 124, 125, 127, 128, 130, 132, 134, 136, 138, 142, 144, 146, 148
Krumeich classification, 34, 39, 95, 97, 101, 113, 118, 129, 148
L
Leber congenital amaurosis, 68, 76
M
Management suggestion step, 95, 97–98, 101, 102, 110, 113, 118, 129, 136, 139, 144
Marfan syndrome, 1 Mitral valve prolapse, 10
Morphological patterns, 13, 49, 57 Munson’s sign, 1
Myopia, 62, 63, 83
N
Nasal temporal, 1, 19
Nipple cones, 13, 14, 41, 60, 73
O
OCT, 2, 77, 81, 83, 84
Ocular response analyzer, 7, 8
Ostoegenesis imperfecta, 1
Oval, 4, 22, 23, 43, 44, 60, 73
Oval cones, 13, 14, 73
Oval pupil, 84
P
Pachy apex, 27 Pachymetry, 9, 41, 42, 64
Paracentral, 9, 13, 14, 43, 45, 46, 56, 64, 68, 88, 102, 122–124 Pellucid-like keratoconus (PLK), 27, 34, 37, 42–57, 70, 72,
76, 95, 101, 102, 118, 121, 122, 124, 125, 128, 130, 134, 135, 143, 144
Pellucid marginal degeneration (PMD), 1, 3, 13, 18, 27, 34, 37, 42–57, 70–73, 76, 87–88, 95, 100–102, 128, 134
Penetrating keratoplasty (PKP), 59–61, 87, 88, 146 Perforation, 13, 68, 70, 125
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Peripheral, 13, 17, 42, 43, 45, 56, 60, 72–74, 84, 87, 122, 123 Peripheral corneal melting disorders, 53
Phakic IOLs, 82, 83 Photokeratoscopy, 3–6 Piggyback, 59, 60 Pigment dispersion, 85 Placido disk, 3–5, 9 Pleomorphism, 7, 8 Polymegathism, 8
PRK, 76, 78–82, 87, 89, 97–99, 101, 102, 110, 111, 113, 116, 118, 124, 129, 130, 136, 137, 139, 140, 144 Progression, 68, 75, 76, 82, 85, 86, 88, 90, 96, 97, 102, 110, 112, 113, 116, 118, 129, 136, 139, 144, 146
Projection based, 9
Q
Qualitative, 9
Quantitative, 9
R
Reflection based, 9
Refractive error, 34, 59, 62, 64, 73, 76, 81–90, 96–98, 100–103, 108, 110–113, 116, 118, 124, 125, 129, 130, 134, 136–139, 144
Regular, 6, 19, 59, 73, 76, 87, 102, 104, 126, 130, 131, 145 Relative thickness map, 42
Retinitis pigmentosa, 1 Retinoscopy, 1 Riboflavin, 75, 77
Rigid gas permeable (RGP), 43, 44, 59, 60, 85, 117, 128 Rizzuti’s sign, 1
Round, 22, 23, 136, 139
S
Sagital, 29, 44, 78, 80 Scheimpflug image, 10, 46, 52, 56
Segment, 19, 22, 26–29, 31, 32, 34, 62–64, 68, 70, 72, 83, 90, 95, 97, 110, 111, 113, 133, 146–148
Sex, 42, 86, 88, 90, 97, 102, 110, 113, 118, 129, 136, 139, 144 Skewed steepest radial axis index (SRAX), 22, 26, 27, 29,
97, 109, 110
Slitlamp biomicroscopy, 1–3, 43, 44, 51, 56, 96, 100, 102, 108, 112, 117, 128, 134, 138, 142
Smiling face, 27, 32 Snellen, 43, 82, 89
Spectacles, 42, 59, 60, 83, 85, 86, 89, 90, 129, 134, 137 Specular microscopy, 8, 83
Sphere, 13, 16, 17, 19, 62, 75, 81, 82, 87, 96, 100, 103, 108, 112, 117, 125, 128, 130, 134, 138, 139, 142
Spherical equivalent (SE), 39, 89
SRAX. See Skewed steepest radial axis index (SRAX)
Steep, 4–6, 13–15, 22, 25, 27, 34, 36–38, 60, 62, 63, 76, 77, 95, 101, 140
Stress lines, 2, 3, 62, 64, 68, 86–88, 90, 96, 97, 100, 102, 108, 110, 112, 113, 117, 118, 124, 125, 128, 129, 134, 136, 138, 139, 142, 144, 146, 148
Stromal haze, 7
Superior, 27, 28, 34, 43, 49, 51, 68, 70, 71, 97 Superior steep (SS), 22, 24, 27, 28, 113
Symmetric bowtie (SB), 19, 20, 22, 25, 26, 36, 109, 110
T
Tangential, 13, 41, 42, 63, 65, 66, 68, 70, 76, 78, 95 Terrien marginal degeneration, 49, 57
Thickness, 27, 34, 39, 41–43, 46, 60–64, 68, 70, 73, 76–79, 81–83, 86–90, 97, 102, 103, 107, 110, 113, 116, 118, 124, 125, 128–130, 134, 136–139, 142, 144, 146
Thickness map, 13, 15, 18, 27, 42, 43, 45, 46, 50, 51, 56, 57, 68, 71, 79, 95, 102, 118, 120, 123
Thinnest location, 3, 27, 34, 46, 50, 51, 56, 60, 62, 64, 68, 73, 76, 77, 82, 87, 89, 90, 97, 98, 101–103, 107, 110, 113, 118, 120, 124–126, 128, 129, 134, 136, 138, 139, 142, 144, 146 Thinning, 1–3, 7, 13, 15, 42–45, 49–51, 53, 56, 57, 68, 75, 76,
86, 87
Tongue like extension, 27 Topography guided PRK, 79 Trauma, 60, 84, 85
Turner syndrome, 1
U
UBM, 83–85
Uncorrected visual acuity (UCVA), 43, 60, 75, 83, 86–90, 96, 97, 100, 102, 103, 108, 110, 112, 113, 117, 118, 124, 125, 128–130, 134, 136–139, 142, 144, 146
Uveitis, 83–85
V
Vernal disease, 1
Videokeratoscope, 9
Viscoelasticity, 6
Viscosity, 6, 86
Visual acuity, 42, 43, 59, 75, 86–87
Vogt’s striae, 2, 3, 43, 117
Vortex pattern, 27, 32
W
With-the-rule, 19, 145–147
Z
Zonular damage, 85