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New options for the intolerant RGP wearer:Minisclerals
Richard VojlayAssociate Professor (Melb Uni) BSc Optom LOSc FVCO
Dip Oc Therapeutics Dip Humanities (Music)
Successful RGP wearer –Keratoconus and Corneal grafts
What is a successful lens?
� Good vision
� Stable
Comfortable
2
� Comfortable
� Quiet eye (not red) with tolerable staining
� Can be reliably worn for most of the day.
� The aim is to generate an even bearing surface across the
cornea/graft, adequate but not excessive edge lift or to vault the
graft completely.
Successful RGP wearer –Keratoconus and Corneal grafts
� RGP KC fitting
� VA with RGP 6/8-2
3
Successful RGP wearer –Keratoconus and Corneal grafts
� RGP Corneal
graft fitting
� VA with RGP 6/5-2
4
Keratoconus and Corneal grafts – RGP fitting
� Fitting irregular and asymmetrical surfaces - KC
5
Keratoconus and Corneal grafts – RGP fitting
� Fitting irregular and asymmetrical surfaces – Corneal grafts
6
Keratoconus – RGP fitting
� Fitting options – Small, Medium or Large
� Small
� Nipple cones
7
� Nipple cones
� 7.8 mm diameter
� Quadcurve
Keratoconus – RGP fitting
� Fitting options – Small, Medium or Large
� Medium
� 9.0 mm diameter
8
� 9.0 mm diameter
� VA with RGP 6/6-2
� Quadcurve
Keratoconus – RGP fitting
� Fitting options – Small, Medium or Large
� Medium
� 10.1 mm diameter
9
� 10.1 mm diameter
� VA with RGP 6/4-2
� Bi-sym CLC
Keratoconus – RGP fitting
� Fitting options – Small, Medium or Large
� Large
� 13.0 mm diameter
10
13.0 mm diameter
� Limbal Lift ACL
(previously K series)
Corneal grafts – RGP fitting
� Fitting options – Small, Medium or Large
� Small
� 9.0mm diameter
11
� 9.0mm diameter
� VA with RGP 6/12-
Corneal grafts – RGP fitting
� Fitting options – Small, Medium or Large
� Medium
� 10.8 mm diameter
12
� 10.8 mm diameter
� VA with RGP 6/6-
Corneal grafts – RGP fitting
� Fitting options – Small, Medium or Large
� Large
� 13.00 mm diameter
13
� VA with RGP 6/6+2
� Limbal Lift ACL
(previously E series)
Quadrant Zoning – inferior tuck
� Fitting options – Very large
� Scleral – custom, trial sets
� 23 mm diameter
Keratoconus and Corneal grafts – RGP fitting
14
23 mm diameter
� May be fenestrated for tear exchange
� Custom lenses can be very labour
intensive to produce
� Trial sets can reduce fitting times and
assist with reproducibility
� Fitting options – Very large
� Minisclerals
15 - 16.0 mm diameter
Keratoconus and Corneal grafts – Miniscleral RGP lenses
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� 15 - 16.0 mm diameter
� Vault cornea from sclera to
sclera
� Sealed system, no tear exchange
� High Dk material
� V with c/l: 6/6-2
Successful RGP wearer – Keratoconus
� Predicting success – what works?, more reliable with keratoconus
Hopefully Very unlikely
16
Unsuccessful RGP wearer – Keratoconus
� Intolerant RGP wearer – options
� soft carrier lens
� SynergEyes
17
� SynergEyes
� referral for an opinion by another optometrist
� referral for a corneal graft or regraft.
� All of these lenses are successful - good vision, reliable wearing times,
stable, good comfort, no graft rejections.
Successful RGP wearer – Corneal grafts
18
�
Unsuccessful RGP wearer – Corneal grafts
� All of these lenses were unsuccessful - good vision, unreliable wearing
times, stable, variable comfort, graft rejections
� Difficult to predict a successful fitting on a corneal graft
19
Patient’s reasons for intolerance –Keratoconus and Corneal grafts
� General discomfort
� Reduced and unreliable wearing times
� Poor quality vision, especially at night
20
� Poor quality vision, especially at night
� Intense discomfort from foreign bodies
� Contact lens instability – unusual eye positions
and sport
� Conjunctival hyperaemia
� Minisclerals - characteristics
� No movement
� No lid interaction
Sealed system – no foreign bodies
Keratoconus and Corneal grafts – Miniscleral RGP lenses
21
� Sealed system – no foreign bodies
underneath the lens
� Tear film reservoir
� High DK material
� Excellent centration
� Large optic zone
� Will not displace
� minimal or no corneal bearing
� Minisclerals – patient experience
� Excellent comfort
� No edge awareness or movement
� Excellent vision – especially at night
Keratoconus and Corneal grafts – Miniscleral RGP lenses
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� Excellent vision – especially at night
� No problems on windy days
� Excellent stability – total security
� Easier to handle, more difficult to lose
� More reliable wearing times
Very comfortable, stable with excellent vision
� Minisclerals - manufacturers
� Eyecon miniscleral – Capricornia Contact Lenses
� Gelflex
Keratoconus and Corneal grafts – Miniscleral RGP lenses
23
� Gelflex
� Contact Lens Centre – SSMax
� KATT – Capricornia Contact Lenses
� Eyecon miniscleral (Capricornia)
� Trial set - base curves: 6.8 – 8.2 mm
� Diameter: 16.00 mm
Keratoconus and Corneal grafts – Miniscleral RGP lenses
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� Diameter: 16.00 mm
� Periphery: standard or flat
� Material: Boston XO
� Fit assessed by measuring tear film depth
� Optimal clearance: 180 – 270 µ
� Avoid blanching of conjunctival vessels
� Eyecon miniscleral – standard or flat edge
� 7.8 (16.00) -1.00, standard edge VA 6/10+2
Keratoconus and Corneal grafts – Miniscleral RGP lenses
25
� Eyecon miniscleral
� staining
Keratoconus and Corneal grafts – Miniscleral RGP lenses
26
� Minisclerals - measurements
� Topography – only out to 8mm
� Corneal sagittal height
Keratoconus and Corneal grafts – Miniscleral RGP lenses
27
� Standard RGP lens curves are based upon the
corneal curvature
� Miniscleral fitting is based on sag, so a flatter
base curve (7.8mm) may vault over a cornea
with maximal curve (6.8mm), due to a shallow
anterior chamber
� Trial lens fitting essential - base curve and sag
� Estimation of anterior chamber depth – The Smith Method
� The Smith method allows the measurement of the anterior chamber depth.
� Turn the beam to horizontal
Keratoconus and Corneal grafts – Miniscleral RGP lenses
28
� Turn the beam to horizontal
� Illumination arm set at 60 degrees
� Use the right eyepiece for the right eye measurement
� Narrow beam
� High illumination
� Minimal beam length
� Focus on anterior lens capsule
� Observe separate out of focus image on endothelium
Keratoconus and Corneal grafts – Miniscleral RGP lenses
29
Keratoconus and Corneal grafts – Miniscleral RGP lenses
30
� Estimation of anterior chamber depth – The Smith Method
� Extend length of beam until the images meet
� Measure the length by reading off the slit lamp
Keratoconus and Corneal grafts – Miniscleral RGP lenses
31
� Measure the length by reading off the slit lamp
� Conversion factor of 1.4 x reading = central anterior chamber depth in mm
� E.g. 3.860, 4.250, 5.154
� Fitting philosophy is based on matching the sag of the eye at a chord of 15mm to
that of the lens with an allowance for apical clearance
Keratoconus and Corneal grafts – Miniscleral RGP lenses
32
� Parameters
� Base curve/optic – cornea zone
Transitional curves - limbal zone, adjusts differences in
Keratoconus and Corneal grafts – Miniscleral RGP lenses
33
� Transitional curves - limbal zone, adjusts differences in
elevation from mid periphery and past the limbus
� Peripheral curves - scleral zone – allows for adjustment
of alignment on the sclera, to reduce or increase edge
clearance
Keratoconus and Corneal grafts – Miniscleral RGP lenses
� Fitting
� Measure corneal sag and select trial lens with next highest sag
� Anaesthetic is optional, can be useful for the patient to experience the lens
34
� Anaesthetic is optional, can be useful for the patient to experience the lens
� Must be inserted bubble free
� Fill lens with saline, add fluorescein
� Inserted using large suction cup holder as a support
� Observe bearing and clearance, tear thickness profile across the lens
� If initially okay, review after 30 minutes
� Removed with DMV-45 assisted by lower lid manipulation
Keratoconus and Corneal grafts – Miniscleral RGP lenses
� KATT (Capricornia)
� Development of KATT from Eyecon miniscleral
� Increased knowledge of scleral curvature, better alignment
35
� Incorporating anterior chamber depth, sag measurements
� Introduction of tangential curves to alter sag
� Material Boston XO2 (Dk 141)
� Tear film: Central clearance – 300 µ, Limbal clearance - 200 µ
� Known Lens centre thickness (300 µ)
� Trial set: 6.0 mm (sag 5.715) to 8.0 mm (sag 3.9844)
Keratoconus and Corneal grafts – Miniscleral RGP lenses
� KATT (Capricornia)
� Spherical or aspheric central
optic zone (10mm)
36
� Tangent curve that runs parallel
to the ocular surface (14mm)
� Second tangent curve zone that
allows for sag variation
� Peripheral curve that meets
the sclera (15.0- 16.5mm)
Keratoconus and Corneal grafts – Miniscleral RGP lenses
� KATT (Capricornia) - Second tangent curve zone that
allows for sag variation
37
Keratoconus and Corneal grafts – Miniscleral RGP lenses
� KATT (Capricornia)
38
Keratoconus and Corneal grafts – Miniscleral RGP lenses
� KATT (Capricornia)
� Patient RU: Diagnosed PMD @ 30, wearing soft c/l's, accountant
� Very poor reaction to RGP c/l’s in late 30’s – very uncomfortable, will not
39
� Very poor reaction to RGP c/l’s in late 30’s – very uncomfortable, will not
try again
� Rx: R +2.50/-7.50x85 VA 6/8-2 L +4.00/-4.50x73 VA 6/8+2 (variable)
� Vision with current soft lenses: R 6/24+2 L 6/24-
� Topography R 7.17 @ 169, 9.44 @ 79
Keratoconus and Corneal grafts – Miniscleral RGP lenses
� KATT (Capricornia) - Patient RU
40
Keratoconus and Corneal grafts – Miniscleral RGP lenses
� KATT (Capricornia) - Patient RU, trial lens inserted with fluorescein
� RE: KATT 7.8 (16.50), sag: 3.9674 after 30minutes
41
Keratoconus and Corneal grafts – Miniscleral RGP lenses
� KATT (Capricornia) - Patient RU
� RE: KATT 8.0 (16.50) sag: 4.1133 7.0 (16.50), sag: 4.4444
42
Keratoconus and Corneal grafts – Miniscleral RGP lenses
� KATT (Capricornia) – Fluorescein added to external tear layer, compare lens
thickness (300µ) to tear lens thickness
43
Keratoconus and Corneal grafts – Miniscleral RGP lenses
� Central NasalTemp
44
Keratoconus and Corneal grafts – Miniscleral RGP lenses
� KATT (Capricornia) - Patient RU - Staining after 11 hours wearing time
� V with KATT: 6/6-2
� Regular daily wear
45
� Regular daily wear
� Up to 16 hours/day
� Excellent comfort
� No difficulty handling lenses
Keratoconus and Corneal grafts – Miniscleral RGP lenses
� KATT (Capricornia) - Patient NW: KC, bilateral grafts, wearing RGP c/l's
� L wearing reverse geometry bitoric 8.2x6.8(10.5) spherical periphery- successful
� V with c/l: 6/15, with over refraction: 6/8-
46
� Lost RGP lens, lab unable to duplicate fitting or Rx (poor VA) + discomfort
Keratoconus and Corneal grafts – Miniscleral RGP lenses
� KATT (Capricornia) - Patient NW: graft, Topography L 6.48 @ 19 / 8.61 @ 109
47
Keratoconus and Corneal grafts – Miniscleral RGP lenses
� KATT (Capricornia) - Patient NW: 6.2(16.50), sag: 5.1969
� V with c/l: 6/6-2
48
Keratoconus and Corneal grafts – Miniscleral RGP lenses
� KATT (Capricornia) - Patient NW: 6.2(16.50), sag: 5.1969
� Staining after wear
49
Keratoconus and Corneal grafts – Miniscleral RGP lenses
� KATT (Capricornia) – Patient AR - KC - previously worn soft c/l's, LE graft
@ 22, farm labourer
� Topography: L 6.43 @ 56 / 7.70 @ 146
50
Keratoconus and Corneal grafts – Miniscleral RGP lenses
� KATT (Capricornia) – Patient AR - LE graft 6.5(16.50), sag: 4.8486
51
Keratoconus and Corneal grafts – Miniscleral RGP lenses
� KATT (Capricornia) – Patient AR - LE graft
52
Keratoconus and Corneal grafts – Miniscleral RGP lenses
� KATT (Capricornia) – Patient AR - KC - RE
� Topography: R 7.13 @ 70 / 7.77 @ 80
53
Keratoconus and Corneal grafts – Miniscleral RGP lenses
� KATT (Capricornia) – Patient AR – RE KC
� CLC Centra PGA
� 7.2(10.1), V with c/l: 6/10-2
54
� 7.2(10.1), V with c/l: 6/10-2
Keratoconus and Corneal grafts – Miniscleral RGP lenses
� KATT (Capricornia) – Patient AR – RE KC
� 7.2 sag: 4.4444
� V with c/l: 6/8
55
� V with c/l: 6/8
Keratoconus and Corneal grafts – Miniscleral RGP lenses
� KATT (Capricornia) – Patient AR – RE KC
56
Keratoconus and Corneal grafts – Miniscleral RGP lenses
� KATT (Capricornia) – Patient AB – KC - R graft, wearing Eyecon
miniscleral in LE
57
Keratoconus and Corneal grafts – Miniscleral RGP lenses
� KATT (Capricornia) – Patient AB – R graft
� After suture removal: Rx RE +2.50/-9.50x167 VA 6/8-
� Topography: R 6.92 @ 78 / 8.77 @ 168
58
Keratoconus and Corneal grafts – Miniscleral RGP lenses
� KATT (Capricornia) – Patient AB – R graft 6.5(16.50), sag: 4.8486
59
Keratoconus and Corneal grafts – Miniscleral RGP lenses
� KATT (Capricornia) – Patient AB – R graft
60
Keratoconus and Corneal grafts – Miniscleral RGP lenses
� KATT (Capricornia) – Patient AB – R graft
61
Keratoconus and Corneal grafts – Miniscleral RGP lenses
� KATT (Capricornia) – Patient SR – KC – bilateral grafts, LE ICL, LE intense
chronic discomfort, LE Rx -6.50 VA 6/15
� Topography: R 6.72 @ 173 / 7.36 @ 83
62
Keratoconus and Corneal grafts – Miniscleral RGP lenses
� KATT (Capricornia) – Patient SR – LE intense chronic discomfort
63
Keratoconus and Corneal grafts – Miniscleral RGP lenses
� KATT (Capricornia) – Patient SR – LE intense chronic discomfort
� V with L c/l + over refraction: 6/6-2
64
Keratoconus and Corneal grafts – Miniscleral RGP lenses
� KATT (Capricornia) – Complications
� Excessive conjunctival bearing
65
Keratoconus and Corneal grafts – Miniscleral RGP lenses
� KATT (Capricornia) – Complications
� Conjunctival hyperaemia Faint diffuse spk staining
66
Keratoconus and Corneal grafts – Miniscleral RGP lenses
� SSMax (Contact Lens Centre)
� 5 zones - Cornea zone, Transitional curves and Peripheral curves
� Overall Diameter: 15.80 mm
67
� Overall Diameter: 15.80 mm
� Material Boston XO (Dk 100)
� Trial set: 6.0 (sag 5.03) – 8.2 (sag 3.54)
� Central clearance: 45 – 50 µ
� Edge width: 0.75 – 1.0 mm
Keratoconus and Corneal grafts – Miniscleral RGP lenses
� SSMax (Contact Lens Centre)
� Each curve is defined by eccentricity and width and can be varied to
increase or reduce the alignment profile across the lens
68
increase or reduce the alignment profile across the lens
� Edge lift to promote tear exchange
� Design Configurations – Spherical, Toric Periphery, Back Surface Toric,
Front Surface Toric, Bitoric, Bi-Sym, Quad-Sym
Keratoconus and Corneal grafts – Miniscleral RGP lenses
� SSMax (Contact Lens Centre) – Patient SR – KC - R graft
� Topography: R 6.93 @ 53 / 8.37 @ 143
69
Keratoconus and Corneal grafts – Miniscleral RGP lenses
� SSMax (Contact Lens Centre) – Patient SR – R graft
70
Keratoconus and Corneal grafts – Miniscleral RGP lenses
� SSMax (Contact Lens Centre) – Patient SR – R graft
� 6.4 sag: 4.60 6.6 sag: 4.45
71
Keratoconus and Corneal grafts – Miniscleral RGP lenses
� SSMax (Contact Lens Centre) – Patient SR – R graft
� 7.8 sag: 3.71 7.2 sag: 4.04
72
Keratoconus and Corneal grafts – Miniscleral RGP lenses
� SSMax (Contact Lens Centre) – Patient SR – R graft
� 7.2 sag: 4.04, V with c/l: 6/8+2, over: +1.50/-2.00x45 VA 6/5
� Front Surface Toric ordered – 7.0 base
73
� Minisclerals - summary
� Another viable option for KC and corneal graft fitting
� Design development is ongoing
Keratoconus and Corneal grafts – Miniscleral RGP lenses
74
� Effective communication with manufacturers is essential when
using complex designs
� Better edge design required to facilitate tear exchange and reduce
conjunctiva compression
Very comfortable, stable with excellent vision