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Keratorefractive & Lenticular
SurgeryMichael Duplessie, MB, BCh
Indications for surgery: Patients who present with a history of or
clinical signs supporting a decrease in vision affecting the patients quality of life. This may be evaluated by: Reduced BSCVA Debilitating glare Monocular diplopia Debilitating halos { I can’t drive at night}
Cataracts:
Cataracts:
Trypan Blue for hypermature cataracts
Traumatic cataract and iridodialysis from Bungee cord inury
Many Corneas:
Corneal melt
Traumatic
Iatrogenic – Pseudophakic disastersAside from power calculation errors there can
be many problems with the lens
Clinical Evaluation
Get as much historical information as possible including: BCSVA pre treatment Pachymetry Ablation depth Flap thickness Pre operative k’s Anterior Chamber depth Axial length
Clinical Evaluation VA: UCVA, BCSVA Refraction
Manifest Cycloplegic Stability
Keratometry Pupillary Exam Pachymetry Anterior Chamber depth Axial length
Clinical Evaluation Slit lamp Tonometry Dilated Fundus examination Pachymetry by ultrasound Topography Placido Ring
Clinical Evaluation Evaluation of BSCVA loss
The etiology of the BSCVA loss or symptoms must be of keratorefractive or lenticular etiology
Retina input always encouraged
Introduction
Before the advent of small-incision cataract surgery, a primary goal of cataract surgery was the prevention and postoperative management of unwanted corneal astigmatism.
With the introduction of astigmatically neutral, small-incision cataract surgery, surgeons have now focused on the reduction or elimination of preexisting corneal astigmatism.
Between 15% and 20% of cataract patients present with more than 1.50 D of corneal astigmatism.
With the rule astigmatism
Against the rule astigmatism
Oblique Astigmatism
Corneal astigmatism in the complicated surgical patient
Options: various cataract incisions, relaxing corneal incisions { LRI, AK } toric intraocular lenses (IOLs), and excimer laser ablation
Endophthalmitis one of the most serious complications of
cataract extraction 95% postoperative cataract surgery.
68% yielded gram-positive coagulase-negative 22% yielded other gram-positive organisms, such
as streptococci and Straphylococcus aureus 6% showed gram-negative organisms. 4% of patients, more than one species was
confirmed
Upward trend in endophthalmitis.
Coincides temporally with the development of sutureless clear corneal incisions:
0.265% in the 2000-2003 period, 0.087% in the 1990s, 0.158% in the 1980s, and 0.327% during the 1970s.
3,140, 650 cataract extractions
Incidence of endophthalmitis
Clear corneal 0.189 – 0.269 %
Blue Line 0.074%
Intracameral 0.004 %
Are you putting yourself at risk ? Your co-managed patient is 67 times more
likely to get endophthalmitis if your surgeon does clear corneal surgery
Topical Antibiotics and Subconjunctival Injections
None of the topical agents penetrates the vitreous appreciably corneal epithelial barrier residual lens-iris apparatus anterior flow of aqueous
Post-operative AC antibiotics and anti-inflammatory medications
Routine Diabetic Retinopathy
0.15 cc 0.2 cc 0.4 cc
Indocin 0.06 mg 0.08 mg 0.161 mg
Ceftazadime 90 mcg 120 mcg 240 mcg
Vancomycin 149.9 mcg 199.8 mcg 399.6 mcg
Dexamethasone 18 mcg 24 mcg 48 mcg
Kenalog 1.5 mg 2.0 mg 4.0 mg
Toxic Anterior Segment Syndrome (TASS) Outbreak UpdateMay 22, 2006
February to May of 2006, over 82 centers in North America have reported cases of TASS following evidently uncomplicated
cataract surgery
To date, there has been no product usage pattern observed that points to any single product, product combinations, or
manufacturer of products used in cataract surgery.
May be related to any of the irrigating solutions, medications, or materials that gain access to the eye during anterior segment
surgery. In addition, factors related to the cleaning and sterilization of instruments.
TASS - common signs: blurred vision, marked increase in anterior segment
inflammation, including hypopyon formation as well as fibrin in the anterior chamber of the eye
Dislocated PCIOL repositioned with rhexis fixation of optic
Relaxing Incisions
Corneal Relaxing Incisions used since the 1970s Single or paired arcuate incisions 99% of the peripheral pachymetry measurements powerful tool limited predictability; often result in
overcorrections no longer "first-line"; patients with high
astigmatism.
Limbal Relaxing Incisions used with any type of cataract incision. easier to perform and more comfortable for the patient than
CRI more "forgiving" ; overcorrections are rare Precise placement "on-axis" is not as critical because the
length of an LRI ranges from 4 mm to 10 mm more forgiving of variation in depth than CRIs. Postoperative refractions are less variable LRIs combined with CRIs placed near the limbus can correct
even higher levels of astigmatism (up to 8 D)
LRI
Relaxing incisions being made prior to routine cataract operation:
Healed LRI
LRI - tools
Toric IOL
Toric IOLs No alteration of current surgical technique Reversible. Preset level of astigmatic correction or it
can be customized to meet the specific needs of a patient
Study Data
In 1994, Shimizu and colleagues the first clinical trial to evaluate toric IOLs.
Reduction of astigmatism in all but one of the eyes It was noted that the closer the IOL came to its
target axis, the greater was the reduction in astigmatism.
Average reduction of astigmatism for the IOL with 2 D and 3 D of astigmatic correction was approximately 1 D and 1.5 D, respectively.
Long-term rotational stability contributes to its success off-axis rotation has a deleterious effect
on visual acuity the maximum rotation of 30° where the
effective astigmatic correction is entirely negated
a toric IOL with postimplantation rotation of more than 30° should be rotated back.
Initial American experience Grabow. astigmatically neutral incision. 95% implanted IOLs remained within 30°
on the intended axis. No other adverse events related to the
insertion of these IOLs were reported
Calculations and alignment: The spherical power of the toric IOL is
calculated in the same way as for a conventional IOL.
Hash marks on the IOL allow this cylindrical power to be surgically aligned with the steeper "plus" axis of astigmatism
Toric IOL prior to insertion
Piggyback Toric IOLs
involves implanting two or more toric IOLs within the eye, in piggyback fashion
Back to back suturing of toric iol
IOL being inserted into the bag
Lens lying on axis in bag
Removal of viscoelastic behind lens
Pre-operative versus post operative cylindrical correction
Toric IOLs Combined with Relaxing Incisions combined to correct larger amounts of
astigmatism reduction in the amount of incisional
surgery required. For many cases of high astigmatism,
adding a toric IOL allows the use of limbal incision rather than corneal relaxing incisions.
Toric IOLs versus spherical IOL with LRIs Toric IOL
84% UCVA 20/40 or better
Spherical IOL/LRI
76% had 20/40 or better uncorrected visual acuity
Piggy Back IOL’s
Piggybacking IOL’s
Can be used to correct pseudophakic refractive errors.
Secondary IOL less traumatic than IOL exchange
IOL implanted anteriorly to the primary IOL
High rate of predictability The power of the secondary implant is
calculated purely by the patient's refraction Can never be certain of the power of the
original IOL. Cannot be confident that an exchanged IOL
would be placed in the same plane as the old IOL.
Lens selection for piggyback IOL AcrySof offers the advantage of a thinner,
6.5-mm optic
Any lens type can be secondarily piggybacked over any other type of IOL. Can use toric lenses.
Contraindications Progressive refractive error Cornea/Endothelial pathology Glaucoma Narrow AC angle Capsular opacification
Contraindications
History of: Iritis Synechiae Pigment dispersion Pseudoexfoliation
Low/abnormal endothelial cell count Keratoconus? (Toric ICL) Patients under age 21
Exam and Testing
Manifest and cycloplegic refraction Unaided and aided visual acuities Keratometry or corneal topography Gonioscopy Pachymetry-corneal thickness Pupil size in normal and mesopic
conditions (6mm or under mesopic)
Exam and Testing Anterior chamber depth Intraocular pressure (IOP) Biomicroscopy-dilated and undilated Opthalmoscopy-dilated Horizontal white to white-operating
microscope/caliper Endothelial cell count (if available)
Excimer laser phototherapeutic
keratectomy (PTK) and Piggyback IOL’s
Introduction a 193-nm argon-fluoride laser is used to
photoablate the affected areas and create a smooth transparent surface.
Compared to manual lamellar techniques, PTK results in controlled deposition of new extracellular matrix and basement membrane, reepithelialization, and stromal remodeling.
Ablation patterns Myopic Sphere Myopic Astigmatism Myopic Elipse
Patient Selection - Ideal candidates are patients with: significant visual compromise, pathology in the anterior one-third of the cornea, an elevated or flat opacity, and recurrent erosions not responsive to medical
therapy. Additional indications include postrefractive
surgery, stromal haze, and intraepithelial dysplasia.
Relative contraindications include: pathology deeper than one-third depth, corneas with central thickness is less than
250 mcg), and active ocular or adnexal infection or
inflammation
Testing includes best-corrected visual acuity, pinhole acuity, rigid gas-permeable contact lens over-refraction, glare testing, pupil diameter in different
illuminations, videokeratography, pachymetry, and, Slit lamp examination. Informed consent is obtained after a discussion of
risks, benefits, and alternatives
Case History Rev. GC 4/22/2002
K’s 41.75 x 9542.50 x 5
Post Op Refraction + 0.25
Chryseobacterium Indologenes Ubiquitous in nature, Chryseobacterium
species are found primarily in soil and water.
Can survive in chlorine-treated water Cause of cancer in plants
Case History Rev. GC 4/22/2002 41.75 x 95 42.50 x 5
Post Op Refraction + 0.25 Va 20/30
10/27/2005 31.6 x 31 36.5 x 12
Refraction + 7.00 with hard contact lens. 12D astigmatism in 3 & 5 mm zones Va LP
Piggyback IOL Current Rx: + 7.00 Desired Post Op Refraction - 1.00
+7 – {-1} x 1.5 = 12 Diopter IOL
11/11/05 12D Piggyback IOL placed12/2005 Therapeutic PTK
Rev. GC Last visit
- 3.00 – 1.50 x 170 20/40
Case History M.W.
7/12/2005 + 7.00 – 2.00 x 19 Va 20/200
7/28/2005 Piggyback IOL
7/29/2005 -0.25 – 1.50 x 105 Va 20/100
10/13/2005 PTK
11/30/2005 - 1.50 Va 20/70
LASER Improvements Tracking/scanning lasers Improved flaps
Femtosecond laser-IntraLase Custom ablations/topography Wavefront ablation
Biomask
Phakic IOLsThe Next Refractive Solution
Collamer Advantages Poly-HEMA based Collagen prevents coating Fibronectin monolayer formation High (1.453) index of refraction Foldable and highly elastic Many designs possible w/ lathe UV absorbing Optical properties closest to human
lens
Visian ICL
Collamer material Injector inserted through 2.8mm incision Current design (V4) is 5th generation Footplates rest in ciliary sulcus Absolute power range -30D to +30D Practical correction range -17.5D to +17D? Cylinder custom power to over 6.0D at any
axis
ICL Material, Designs and Specs
Myopic Visian ICLMyopic Visian ICLHigh Resolution Magnetic Resonance Images High Resolution Magnetic Resonance Images
Illustrates the Increased Vault with V4Illustrates the Increased Vault with V4
Version V3 Version V4
< 100 microns:
< 50 microns
500-600
microns
Vault Illustration
LASIK vs. ICLCONCURRENT COMPARATIVE
SERIES WITH 8-12 D OF PRE-OP MYOPIA
John A. Vukich, M.D.Donald R. Sanders, M.D., PhD.
BSCVA 20/20 or Better
0
20
40
60
80
100LASIK ICL
60%60%
76%76%82%82% 82%82%
75%75%
90%90%89%89%88%88%82%82%82%82%
PrePre
1Wk.
1Wk.
1 Mo.
1 Mo.
6 Mos.
6 Mos.
1 Yr1 Yr
%%Of Of CasesCases
*p *p 0.050.05**p **p 0.010.01
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