Therapeutic Contact lenses

Manoj Aryal
B . Optometry
Institute Of Medicine,
Maharajgunj Medical campus

Introduction
Classification of TCL types
Essentials of fitting a TCL
The aims of therapeutic contact lens wear
Complications associated with therapeutic
contact lenses wear
Aftercare
Conclusions
Therapeutic contact lens (TLC)

 Definition:
The term “therapeutic” is derived from
the Greek word “therapeuein” meaning
to take care of, or to heal.
 Mainly fitted with the aim of
attempting to maintain or restore the
integrity of ocular tissues.

The five main aims of therapeutic
contact lenses are:
1. Relief of ocular pain;
2. Promotion of corneal healing;
3. Mechanical protection and support;
4. Maintenance of corneal epithelial
hydration;
5. Drug delivery

Silicone rubber and silicone hydrogels
(38%);
Hard (PMMA) and gas permeable scleral
lenses;
Hard scleral rings;
Hydrogel soft lenses
 Low water content ( 38%-45%);
 Mid-water content (45%-55%);
 High water content (67%-80%);
Collagen shields

Silicon Hydrogel
They offer theoretical advantage of
oxygen transmissibility and is more
suitable for overnight wear
The disadvantage includes the
increased rigidity, poor surface
wettability, and limited parameters

For painful eyes with irregular corneas,
the more soft or flexible the lens the
more likely an acceptable and
comfortable fit will be achieved
Lens deposition may be a problem
especially mucin balls
The increased rigidity may also be
expected to increase the risk of CL
related papillary reaction, conjunctivitis
and SEAL

Applications:
Main application is for wound healing
(persistent epithelial defect, corneal
ulceration etc.).
 They are used for the apposition of
wound edges and pain relief.
Corneal ulceration
Persistent
epithelial defect

However, the applications may be
constrained by the limited range of
total diameters and limited choice
of BOZR
Some lenses are not available in
Plano power, some patients with
good visual acuity may not tolerate
the change in induced ametropia,
such as RCE patients with a VA of
6/5

Silicon rubber
Silicone rubber lenses are difficult to
fit.
 The total diameter must closely
correspond to the corneal diameter
 Some movement and tear exchange is
essential and uniform edge clearance
and central corneal alignment is
desirable but rarely achieved.

 The lenses often steepen unpredictably
and can bind to the cornea.
 Thus the fit should be checked
immediately following insertion, then
again after a few minutes, and after one
to two hours and also the following day.
 Lens removal can be difficult,
especially on a dry eye

Properties and application:
 Has a high oxygen transmissibility (Dk 200-
400), and absorbs no water so lens
parameters are independent of hydration,
tear quality or exposure.
The lenses are also robust and flexible but
they must be coated to improve surface
wetting.
Until recently they were the first choice for
the maintenance of corneal hydration, e.g.
Sjögrens syndrome, exposure and

They also offered protection of the ocular
surface from eyelashes, keratin,
exposure, and glue.
In the presence of a severe dry eye
silicone rubber lenses improved the
ocular environment to assist wound
healing of a corneal perforation and to
promote re-epithelialization of a
persistent epithelial defect.
The lens was also used to provide pain

With a typical diameter of 23mm,RGP scleral
lenses offer protection of both the cornea and
the bulbar conjunctiva.
If the lens is fitted to give corneal and limbal
clearance the lens will maintain a tear
reservoir while protecting the cornea from the
shearing forces of the eyelids.
Thus Sjögrens, cicatrizing
conjunctivitis and corneal exposure are
typical indications.

Irregular or abnormal corneal
topography
High astigmatism
Keratoconus or other primary
corneal ectasia
Corneal transplant
Traumatized eye
Post-refractive surgery

High refractive errors
 Centration difficulties with high-power corneal
lenses.
 Intolerance to corneal or hydrogel lens wear in
myopia or hypermetropia
Iris encapsulation
 Intractable diplopia.
 Cosmetic shells.
 Unsightly blind eyes.
 Aniridia. Microphthalmos.

Therapeutic or protective
applications
Corneal hydration in serious dry eye
conditions such as
Stevens Johnson syndrome and cicatricising
conjunctivitis, ocular pemphigoid
Prevention of tear film evaporation with poor
lid closure or lid absence
Corneal protection against trichiasis or lid
margin keratinisation
Preventing mucus filaments adhering to the
cornea

Other indications include:
Maintenance of fornices
Ptosis prop
Promotion of epithelial healing in the
presence of a severe dry eye, and
 Rarely pain relief, neurotropic
keratitis and persistent epithelial
defects

Excessive Protrusion in keratoconus
& Scleral Lens Wear

RGP lens that covers the cornea has
the advantage of:
 Offering complete corneal protection
 Maintaining a corneal tear reservoir and
 Can be used with topical medication.

Also lenses with a high oxygen
transmissibility are available
Which flex less than silicone
rubber, so are less likely to bind.
The lenses can be used in severe dry
eye, corneal exposure, trichiasis, and;
in these cases they assist with wound
healing and may even offer pain relief

May be used to promote re-epithelialization.
 They mould to the shape of the cornea and
dissolve over time so they have been
advocated for managing epithelial defects.
However, they are uncomfortable, give poor
vision, the cornea cannot be examined
through the shield, the dissolution rate is
variable and unpredictable, and finally they are
difficult to remove.

Lens type Primary indications
1)Hydrogels Pain relief
a) Thin mid water content with high
bound water
First choice incl.- irregular
corneas, mild to moderate dry eyes
b)Steep hydrogel lenses For step corneas
c) Large hydrogel lenses For limbal and scleral defects and
buphthalmos
2) Silicon hydrogels For wound healing, apposition of
wound edges, short term
mechanical protection
3) Rigid gas permeable Corneal protection, maintenance of
corneal hydration, promotion of
epithelial healing
4) Scleral Mechanical protection of ocular

Slit lamp
The presence of an anterior segment
disorder commonly renders the patient
photophobic so the ability to diffuse
light and/or reduce the intensity of the
slit lamp beam is of particular value in
minimizing patient discomfort

 Keratometry
 Generally not necessary for adequate
fitting of soft bandage lenses.
 However, it may have a value in monitoring
the progression of some conditions, for
example, keratoconus and progressive
corneal dystrophies
In the presence of gross corneal distortion
and the absence of any corneal graft,
measuring K-readings of the fellow non-
diseased eye can provide a useful guide.

 Lens selection
A thicker lens may be more desirable when
the function is to act as a splint (as in
descemetocele) or to cover an irregular
corneal surface
Thicker lenses may also be desirable in some
cases of tear film instability to support a
more stable tear structure.
A thinner lens is more appropriate in cases
of epithelial disruption (for example,
recurrent erosion)

Ideally, a well fitting bandage lens should
provide full corneal coverage, be
centered, with adequate movement
(>0.25mm with each blink) to allow
clearance of debris.
It is important for the lens fit to be stable,
avoiding excessive movement, as this can
cause discomfort or further epithelial
disruption.
Stability can be enhanced by increasing

 Parameter range
The majority of ‘bandage lenses’ used are
Plano or near Plano prescription.
In most circumstances, soft lenses of
standard total diameters 14.0mm to
14.5mm will suffice.
 Larger diameter lenses (15mm to 20mm)
may be required where the specific
function is to protect the limbus or prevent
wound leakage at suture or incision sites
Larger diameter lenses require flatter back
optic zone radii to achieve the desired fit.

Lens stability
 Both a stable fit and minimal
dehydration are desirable.
In cases of irregular corneas, such as
advanced cases of keratoconus or post
surgery, a stable fit may not be
achievable with a single lens material.
Piggyback or hybrid lenses can offer
success in cases when acceptable
centration cannot be achieved with a an
RGP alone.

Helpful when RGP lens is intolerable due to
staining and patient reluctant to surgery
where a rigid corneal lens is worn over a
soft lens
Soft lens
Extra limbal negative or Plano soft lens
(mod. To high Dk)
RGP lens (TD – 9.0 & 10.0 mm)
Disadvantages
RGP rides low with little or no movement
Localized hypoxia & neovascularization
Difficult to handle/maintain two types of
lenses

Avoid the use of topical anesthetics as this
may mask the pain associated with a poor
fitting lens.
The lens fit should be assessed after
approximately 20 minutes and ideally again
after approximately 60 minutes (owing to
lens dehydration effects).
Peripheral lens fit is also very important as
e.g. flared lens edges may gives rise to
discomfort etc.
A well fitting TCL should have good corneal

First Last
Poor corneal
coverage
Increase total
diameter
Steepen
BOZR
Excess lens
movement
Reduce
thickness
Steepen
radius
Increase
diameter
Lens too tight Reduce
thickness
Flatten radius Decrease
diameter
Irregular
ocular
surface
Low modulus
of
elasticity
Thin lens
Dry eye/
exposure
High bound
water
Reduce water
content
Non-ionic Increase
thickness
Restricted
Fornices
Reduced
diameter,
typically
13.00mm

The cause of ocular pain includes:
Exposed or compressed nerve endings in
recurrent corneal erosion, Thygeson's
disease, and bullous keratopathy
 Tension from the eyelid on mucous-
epithelial tags in filamentary keratitis and
superior limbic keratitis.
 Mechanism: lens protects the cornea from
the shearing force of the eyelid during blink.
Aim 1: Relief of pain

This condition of chronic edema of the
cornea can be extremely painful.
Main aim of the therapeutic lens:
 alleviate the symptoms of pain, epiphora,
photophobia and blepharospasm and also
attempt to reduce the chronic edema
Endothelial cell malfunction is frequently a
common factor

Malfunction of endothelium may occur as the
result of a dystrophic process such as Fuch’s
dystrophy
Fuch’s dystrophy usually begins with
guttation of the corneal endothelium
It is bilateral but usually asymmetrical
The guttation are initially seen in the central
cornea and spread peripherally.
Slight stromal edema occurs and is eventually
followed by epithelial edema and bullous

1. In a patient with a painful eye with no
visual potential:
& 2. In a patient who is not fit for graft
surgery.
 Action
 This is best fitted with a TCL as soon as possible.
 Lens movement should be minimized and
 Is best achieved by the employment of a
large, hydrogel lens with high water content
to maintain the maximum oxygen
permeability for continuous wear.

3.As a temporary measure where a
patient is going to have a
penetrating keratoplasty at some
future date.
Action:
 A thin high water content TCL is indicated
due to the reduced risk of producing
corneal vascularization.

Action:
 In severe cases a
high water content
TCL could be
considered where
the main function is
to act as a pressure
bandage thus
relieving pain and
foreign body
sensation.Severe filamentary keratitis in a mucus sheet in a
patient with severe dry eye due to Sjögren's
syndrome

It consists of recurrent episodes of fine
superficial greywhite punctate corneal
opacities of presumed viral etiology.
 The corneal opacities distort the
epithelial surface and may even reduce
visual acuity.

Action:
In severe cases a high water content
TCL could be considered where the
main function is to act as a pressure
bandage thus relieving pain and
foreign body sensation.

Action:
TCLs are very
effective in
alleviating both
signs and
symptoms of the
disease.
Consider a
relatively large

A. RECURRENT CORNEAL EROSION:
Anterior membrane dystrophies
Action:
 TCL used on an extended wear basis for 2, 3 or even
6 months.
 Ultra-thin TCLs are contraindicated due to possible
buckling or wrinkling of the lens with lid movement,
thus producing an ineffective corneal splint action.
 A thick, high water content extended wear lens is
preferred.
 “Disposable” lenses are recommended.

 B. Traumatic corneal abrasions:
Abrasions over 4mm may benefit
from the use of TCLs
Action:
The use of disposable lenses is
indicated, particularly in the treatment
of corneal erosions with good success

 C . Persistent corneal epithelial
defect
 Cornea is more vulnerable to infection and
therefore PED is associated with a
High rate of ulceration and
perforation
Action:
 TCLs (e.g. “disposables”) can provide mechanical
protection from the lids.
 Collagen shields hydrated in acidic fibroblast

D. Chemical injuries
Chemical injuries may suffer severe
stromal ulceration due to the
collagenolytic activity unleashed.
The presence of a TCL may inhibit the
passage of certain proteolytic enzymes
present in the tear fluid to the stroma,
thus preventing the progressive
ulcerative process following chemical
injuries

Action:
A chemical burn to the eye is often
associated with chemosis as well as the
epithelial damage.
Therefore: -
 A small total diameter TCL is the lens of
first choice (TD~12.5mm).
If the lids are involved, a scleral lens
may be better

E . Postoperative epithelial
disorders:
Many ophthalmic surgical procedures
can result in temporary corneal
epithelial defects.
These include:
Vitrectomy
Post penetrating keratoplasty in the early
post operative period
 Epikeratoplasty
 Kerato-refractive procedures e.g. PRK,

Action:
Soft and collagen TCLs may be utilized in
order to minimize post surgical epithelial
trauma, provide a stable healing
environment and promote rapid healing
F. Penetrating keratoplasty
A silicon rubber TCL may be used to
reform the anterior chamber

A. CORNEAL LACERATION
Action:
 With small perforations (less than 2mm)
without tissue loss, structural support may
be achieved and the integrity of the eye
maintained, by the utilization of a TCL
Perforations close to the limbus and those
in vascularized areas respond most
favorably to the application of TCLs.

Partial thickness corneal lacerations
involving stroma, with the wound edges
well a positioned can be treated with a
TCL.
 A small perforation near the visual axis
may heal with less resultant
astigmatism if a TCL rather than a
suture is used.
 A thin low water content soft lens

B. TRABECULECTOMY
Large (total diameter 20.5mm), high
water content TCLs can be fitted to press
over the leaking bleb
C. CORNEAL THINNING
Fit a hydrophilic TCL to act as a corneal
splint, which can retard or even stop the
rate of thinning and hence prevent
perforation.
As this often occurs in dry eyes, silicone

D. PROTECTION OF CORNEA
TCLs and particularly scleral lenses are
very useful in providing protection and
comfort in Trigeminal (5th) nerve palsy,
Facial (7th) nerve palsy.
Consider a pre-formed scleral lens.
Other situations include: -
Lid deformities with eye exposure
 Entropion,
Trichiasis
Scarred lids.

A. CICATRIZING CONJUNCTIVAL DISEASE
Stevens-Johnson Syndrome
Ocular pemphigoid
Chemical burn
Trachoma
Pseudo-membranous and membranous
conjunctivitis
Atopic keratoconjunctivitis
Dry eyes

I) Steven’s Johnson syndrome:
B/L conjunctivitis is a feature
Which usually lead to scarring of the
conjunctivas
Severe irreversible changes such as
scarring, keratoconjunctivitis sicca,
symblepharon, entropion and trichiasis
may occurs

Treatment with scleral lens or ring is usually
helpful
A scleral lens does also retain a tear layer in
front of the cornea and this helps in reducing
corneal keratinization and provides better
vision by negating the optical effects of
corneal irregularities
It is desirable to use a very large(15-20mm),
low or medium water content lens to prevent
adhesion forming or re-forming

Thin lens : tend to distort and wrinkle
Better to use thicker more rigid
lens and
 Low water content lenses: tend to become
coated too quickly to deposits
Use of medium water content
lenses(55%) relatively thick lens seem
optimal
Large sophisticated multi-curved

II) THE DRY EYE:
 In marginal to severely dry eyes
hydrophilic TCLs are not
recommended.
 Silicone rubber lenses may be
considered

 III) Ocular pemphigoid
Therapeutic contact lens indicated:
To protect the cornea against the action of
ingrowing lashes and malposition of lids
Thin lenses are to be avoided and
thicker lenses are preferred
Lens must be large enough

In earliest stage
Presence of soft
immature follicles
in the upper tarsal
conjunctiva
A punctate
keratitis
Early superior
corneal pannus
In late stage
Cicatrization of
lids
Symblepharon
Trichiasis
And distortion of
lids
Therapeutic contact lenses can be used to
separate inflamed tissue to prevent
symblepharon and to avoid the effects of
ingrowing lashes

Hydrogel TCLs alter the pharmacokinetics
and effectiveness of topically applied
drugs.
Hydrogel lenses soaked in medication and
then placed on the eye generally give very
high ocular levels of medication that
diminish with time which are superior to
frequent topical application of drops
alone.
 Medication impregnated lenses are
appropriate for short-term use when

Reducing the effect of aqueous leaks
Improvement of vision
Protection of cornea during tonometry
Maintenance of conjunctival formices
 Ortoptic uses
 Control of refractive errors

Reducing the effect of aqueous leaks
Perforation in the anterior segment which
lead to loss of aqueous fluid can often be
controlled by a tightly fitting soft contact
lens which partially seals the perforation,
whether it be created by trauma or surgery.

Improvement of vision
RGP and scleral lenses can provide a
regular anterior refracting surface and
improve the visual acuity considerably.
In cases of extreme corneal sensitivity or
irregularity, where contact of the cornea
with a hard surface is inadvisable, a rigid
lens can be fitted on top of a soft lens to
provide the required, regular refractive
surface.

Maintenance of conjunctival
formices
May occur in several scarring disease
of mucosa, for e.g. erythema
multiforme, ocular pemphigoid and
chemical burns.
Although a scleral lens is commonly
used to separate the tissue surfaces, a
very large and reasonably soft contact
lens can be used for same purpose.

 Ptosis props
If the eyelid occludes the visual axis, a
ptosis prop may be required.
A modified scleral lens may be successful
depending on the force closing the eyelid.
 Indications include:
Ocular myopathy,
Myasthenia gravis, eyelid trauma and
Neurological problems (e.g. Third nerve
palsy).

Signs:
Loss of corneal sensitivity
Epithelium becomes dry and areas of
necrosis eventually occur
Daily wear of large medium water
content soft lens is better
If extended wear is preferred, then 2 or
more lenses should be alternated daily in
order to keep the lenses clean

Orthoptic uses
A contact lens may be used as a cosmetic
occlude in cases of intractable binocular
diplopia
Any type of contact lens may be used
Usually, complete occlusion can only be
achieved by having an opaque iris pattern
and opaque pupil

In squint treatment, contact lens occlude
have been used before the better eye to
assist in eliminating diplopia
Partial occlusion with contact lenses has
also been used in the treatment of
suppression
The fitting of anisometropic amblyopes
with contact lenses has brought about
some dramatic improvements in the
visual acuity and assisted in the orthotic
treatment of squints in such cases

Orthokeratology
 Non surgical clinical technique that uses
specially designed and fitted Rigid CLs(flat
fit)
 To reshape the corneal contour
 For temporal modification and elimination
or reduce refractive errors

Principles:
 Corneal Shape Change
 Compression/redistribution of fluids/cells from
the center to periphery
 Thinner central corneal epithelium
– Positive pressure from a flat central
lens curve
 Thicker mid-peripheral corneal epithelium
– Negative pressure from tear pool
under steep 2nd (reverse) curve
Control of refractive
errors

Advantages
To be free of
both CLs and
spectacle all day
Ideal for
sportsman,
swimmers or
those who work
in dusty or dirty
environment
Ideal for contact
lens intolerant
Disadvantages
Patient needs
meticulous
follow ups
Retainer lens
wear is essential
throughout the
life
The degree of
success is high
but cannot
always be

Good Candidates
Moderate to low
level myopes (-
1.00D to -5.00D)
 <1.50D
astigmatism
 Corneal diameters
greater than
11.00mm
 Soft lens /
Poor Candidates
High level
myopia/astigm
atism
Against the rule
astigmatism >
0.75D
 Current GP /
past PMMA lens
wearers

A red contact lens, of peak transmission
595nm worn in one eye only has been
recommended by La Bissorniere (1974).
Known as the X-Chrome lens, during
binocular viewing it gives rise to a different
perception of hues, altering their saturation or
brightness, and the wearer learns to relate that
appearance to a particular color name.

CHOICE FIRST LAST
Pain
relief
Hydroge
l
Silicon
hydrogel
Scleral Limbal
RGP
Epithelia
l healing
Silicon
hydrogel
Hydroge
l
Scleral Limbal
RGP
Perforati
on
Silicon
hydrogel
Hydroge
l
Scleral Limbal
RGP
Sensitive
type
Hydroge
l
Silicon
hydrogel
Scleral Limbal
RGP
Ease of
fit
Hydroge
l
Silicon
hydrogel
Limbal
RGP
scleral

SEVERIT
Y
MILD SEVERE
Exposur
e
Hydrog
el
Silicon
hydroge
l
Limbal
RGP
Scleral
Dry
eyes
Hydrog
el
Silicon
hydroge
l
Limbal
RGP
Scleral
Corneal
protecti
on
Hydrog
el
Silicon
hydroge
l
Limbal
RGP
Scleral
Irregula
r ocular
Hydrog
el
Silicon
hydroge
Limbal
RGP
Scleral

Patient
related
 Severity of ocular
pathology
 Concurrent dry eye
 Concurrent topical
corticosteroids
 Poor compliance
– ocular hygiene
– general hygiene
 Poor general health
 Lack of motivation
Lens
related
Hypoxia
– low water
content
– thick lens
Deposition
Mechanical
insult
– poor fit

 The patient should be informed of the
benefits and risks of therapeutic lens wear
In view of potential increased risk of microbial
keratitis, prescribe antibiotics for prophylactic
purposes, especially in the presence of an
epithelial defect
Patients often benefit from the use of non-
preserved wetting drops to insert upon
waking.

The use of medication in ointment form
is not usually appropriate because of
the effect on lens wettability and vision
Lens-related effects can be minimized
by the practitioner choosing the best
lens type for an individual patient.
Maximizing oxygen transmissibility will
limit hypoxic effects

 Frequent lens replacement is an
effective way of management of
deposits
 Lid hygiene procedures should be
explained and demonstrated, and
 For those patients wearing therapeutic
lenses on a daily wear basis the
importance of hand washing, prior to
touching the eye or lenses should be
reviewed at each aftercare visit

Hydrogel Silicon
hydrogel
Silicon
rubber
Rigid:
corneal
Rigid:
scleral
Fluorescein
Ointments
?
V.A. V.A. V.A. V.A.
Preserved
Rx
Short term Short term
Un-
preserves
Rx

Practitioners should be aware the lens
fit may change as the therapy
progresses.
Visual acuity should be measured and
recorded at each visit
Patient is well instructed on both the
need for good hygiene and what action
to take if a problem arises

It is usual for a bandage lens to be worn
overnight, hence the lens fit and ocular status
should be reviewed again after the first night
of wear.
In contrast, in cases such as bullous
keratopathy where the lens provides pain
relief, regular lens removal and replacement
is desired.
In such cases the use of disposable
lenses is beneficial.
The silicone hydrogel lens has proved
very successful in the management of this

Contact lens fitting for therapeutic
purposes is not a part of mainstream
practice, practitioners should be familiar
with its practice and the techniques
involved to enable them to provide
advice and appropriate levels of
aftercare.
 The objective is rarely to achieve an
optimal visual result, rather to protect or

 The same high level of care must be
taken in all aspects of the contact lens
fitting and aftercare process.
 Close collaboration with the medical
management of the condition is
required.
Therapeutic contact lens practice can be
challenging, but often rewarding as it
can lead to dramatic improvements for
the patient in reducing discomfort and
aiding the healing process

Anthony J Phillips and Janet Stone
CONTACT LENSEs
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