Download Scleral Lens Fit for Symptomatic Patient with Keratoconus William J

Scleral Lens Fit for Symptomatic Patient with Keratoconus
William J. Denton, OD, FAAO
Home:
822 Acacia Dr.
Sumter, SC 29150
(803)236-7589
[email protected]
Work:
6439 Garners Ferry Rd., Optometry Clinic – 2D153
WJB Dorn VAMC
Columbia, SC 29209
[email protected]
ABSTRACT:
Introduction: Keratoconus is a near central corneal thinning at the layer of the stroma, creating a physical out-pouching
and optically irregular astigmatism and associated aberrations, which can lead to further complications causing
decreased vision and most likely surgery. Case Report: DC is a 56 year-old Caucasian veteran came to the WJB Dorn VA
medical center contact lens clinic with a long history in our program starting before 1998. Recently, he presented with
keratoconus with substantial complaints related to allergic conjunctivitis and dry eye syndrome. Conclusion: Switching
him from his present contact lens system to scleral lenses has dramatically improved his symptoms, proven with the
Ocular Surface Disease Index (OSDI) questionnaire.
Key Words: Keratoconus, Piggyback Fitting Method, Dry Eye Syndrome, Scleral Lenses
INTRODUCTION:
Keratoconus is a near central corneal thinning at the layer of the stroma, creating a physical out-pouching
and optically irregular astigmatism and associated aberrations. Clinically inferior keratometry readings
can determine the extent of the disease. Less than 48D would be considered mild, 48-54D as moderate
and greater than 54D as severe.1 The prevalence of keratoconus is 8.8 to 54.4 per 100,000 with no gender
predilection. 2 There are too many disease associations with keratoconus to list in this case report. They
include multisystem disorders, systemic disorders, ocular disorders and other corneal disorders. The
offspring of patients with keratoconus are only affected in approximately 10% of cases. It is observed
that keratoconus has an autosomal dominant inheritance with incomplete penetrance.1 This report will
concentrate on clinically relevant information. A patient with unilateral keratoconus, would be more rare;
however, it is more likely that it is bilateral with an asymmetric presentation.1 Asymmetry is more likely
earlier in life as the disease begins at puberty and progresses until the third to fourth decade of life.1,3
CASE REPORT:
DC is a 56 year-old Caucasian veteran who came to the WJB Dorn VA medical center contact lens clinic
with a long history in our program starting before 1998. He was diagnosed early on with keratoconus and
was managed with many types of contact lenses including: Soper rigid gas-permeable (RGP), three
different Boston material lenses, Rose K, Dyna Z large diameter, piggyback style, and Synergeyes prior
to being considered for scleral contact lenses. Additionally, DC has quite a history of ocular allergies,
dryness, and hordeola. Over the last ten or more years he was given carboxymethylcellulose ophthalmic
solution, ketorolac ophthalmic solution, olopatadine ophthalmic solution, gentamicin ophthalmic solution
(infection), lanolin ophthalmic ointment, Restasis® ophthalmic emulsion, tobramycin ophthalmic solution
(infection/allergy), rimexolone ophthalmic suspension , cromolyn sodium ophthalmic solution,
chlorphenamine tablet, and punctal plugs in no specific order. The patient also found that Similasan, an
herbal eye drop preparation, also assists greatly. His son also had been diagnosed with keratoconus and
was applying for disability, did not have a valid driver’s license and was without employment.
DC’s ocular health has been managed for over ten years in the optometry disease clinic. The posterior
pole was unremarkable during the last examination.
DC was our first contact lens patient who was fit with scleral contact lenses in our clinic. After proper
training and receiving trial sets, DC jumped at the opportunity to try anything that may allow for better
comfort, improvement in his vision, or at least a decrease of his dryness symptomology. It is important to
state that he was content with his previous contact lens situation, which consisted of SynergEyes Clear
Kone hybrid contact lenses (SynergEyes, Inc, Carlsbad, CA). He routinely had to take his lenses out at
least every two hours to clean them. He also had severe dryness symptoms and used Restasis®
ophthalmic emulsion bid ou, Similasan (#2 Allergy) drops q30min OU, lanolin ophthalmic ointment and
olopatadine ophthalmic solution bid ou. He was given the Ocular Surface Disease Index (OSDI)
questionnaire and reported a 64.5 index prior to scleral lens fitting. He was asked to quantify his quality
of life (scale: 1 worst, 10 best) before fitting with scleral lenses and he stated a 3, because of all the drops
and cleaning he had to do. Despite his enthusiasm to try any other option, he did acknowledge it may not
be any better than his current situation. He was encouraged to be fit with scleral contact lenses in order to
improve his dryness and allergy symptoms, meanwhile keeping his present level of visual acuity.
Systemic diseases/complications and treatments included:
Problem:
Carpal Tunnel Syndrome
Degenerative Disc Disease
Gastroesophageal Reflux Disorder
Gout
Keratoconus
Hyperlipidemia
Sleep apnea
Dry Eye Syndrome
Seasonal allergies
Medication/Device:
Naproxen
Omeprazole
Allopurinol
RGPs
Gemfibrozil
Simvastatin
CPAP machine
Lubricating ophthalmic
ointment
Refresh artificial tears
Similasan eye drops #2
Allergy
Restasis® ophthalmic
emulsion
Loratadine
Asthma
Fluticasone
Albuterol
Initial Visit:
DC had a long history of contact lenses with varying results. His last contact lens parameters were:
Habitual Contact Lens Parameters:
OD:
Clear Kone hybrid lens (SynergEyes, Inc, Carlsbad, CA)
Power:
+4.50
Base Curve:
2.00 vault, medium skirt curve
Diameter
14.5
Assessment:
*Very little movement
*Centered
*Appropriate edge
*Good vision
OS:
Piggyback Method
Intralimbal RGP (Lens Dynamics, Inc., Kansas City, MO)
Power:
-3.00 D
Base Curve:
6.75 BC
Diameter:
11.2
Focus Night & Day (CIBA VISION Corporation, a Novartis AG Company)
Power:
-0.50 D
Base Curve:
8.4
Diameter:
14.5
Assessment:
*Very little movement
*Centered
*Appropriate edge
*Good vision
Habitual glasses prescription: (from ten years ago)
OD: -9.00-5.00x135
OS: -4.00-3.50x135
+2.50 FT
*Patient does not wear his glasses.
The anterior segment examination showed the following signs: some corneal thinning (PACHs: 448 OD,
406 OS), quite obvious Munson’s sign OU, a trace amount of apical scarring OU with a Fleisher ring,
Vogt’s striae OU, trace diffuse conjunctival injection, early pingueculae nasal and temperal OU, <1mm of
neovascularization on the cornea 360o and 1+ central corneal staining OU. His puncta were open and
without punctal plugs. His previous dilated examination showed no additional ocular health concerns.
Keratometry was not performed prior to this fitting. It is suspected that this was done prior to the
implementation of computerized records and that each RGP fit was changed slightly from the prior
habitual fit. DC was fit with scleral lenses without initial keratometry readings or corneal topography. It
was solely performed through trial and error.
The initial few trial lenses were inserted OD without allowing for settling time due to an inadequate fit.
The last/fourth lens was inserted with fluorescein strip coloring the fluid and allowed to settle for
approximately thirty minutes. The patient was instantly impressed with both the comfort and the visual
acuity once the over-refraction was determined. The same lens was started in the OS and a flatter base
curve was initially ordered.
OD:
Jupiter (Essilor Contact Lenses, Denver, CO)
Diameter:
15.6
Base Curve:
6.37
Power:
-13.00 D
Over-refraction:
+6.25 D 20/25
Assessment:
*No bubbles with adequate clearance central/peripheral
*Well centered
*No blanching
Subjective: Good vision; good comfort.
OS:
Jupiter (Essilor Contact Lenses, Denver, CO)
Diameter:
15.6
Base Curve:
6.37
Power:
-13.00 D
Over-refraction:
+4.75 D 20/25
Assessment:
*No bubbles with adequate clearance central/peripheral
*Decentered 1mm nasally
*No blanching
Subjective: Good vision; good comfort.
Order #1:
Second Visit:
At the follow-up appointment, the lenses were inserted with fluorescein strips coloring the fluid and
allowed to settle for approximately thirty minutes (Figures 1-6).
OD:
Jupiter (Essilor Contact Lenses, Denver, CO)
Diameter:
15.60
Base Curve:
6.37
Power:
-6.75 D
Over-refraction:
+1.25 D 20/25
Assessment:
*No blanching
*Good central vault without touching peripherally.
*Well centered
Subjective: Patient extremely pleased with vision and comfort.
OS:
Jupiter (Essilor Contact Lenses, Denver, CO)
Diameter:
15.6
Base Curve:
6.37
Power:
-8.25 D
Over-refraction:
+1.25 D 20/20
Assessment:
*No blanching
*Good central vault without touching peripherally
*Well centered
Subjective: Patient extremely pleased with vision and comfort.
Order #2:
The patient was instructed to use a peroxide-based cleaning system, which he was already using with
great success. He also was instructed to pick up 0.9% sodium chloride inhalation solution (off label) at
the VA pharmacy window for insertion of the lenses. Insertion and removal training was performed and
the patient picked it up quite easily. The lenses were given to the patient so he could practice insertion
and removal, but was warned that if he wore them that headaches and eye strain at near would occur. The
change in the over-refraction was made and the patient was called for the next appointment when his next
pair of lenses arrived.
Figures 1-3: OD fit
Figures 4-6: OS fit
Third Visit:
When DC arrived to this visit, he was given the newest lenses to insert himself to observe his technique.
He was quite proficient and it was obvious he had been practicing insertion and removal of his lenses. No
fluorescein strips were used prior to insertion.
OD:
Jupiter (Essilor Contact Lenses, Denver, CO)
Diameter:
15.60
Base Curve:
6.37
Power:
-5.50 D
Over-refraction:
plano 20/20
Assessment:
*No blanching
*Good central vault without touching peripherally
*Good centration
Subjective: Patient extremely pleased with vision and comfort.
OS:
Jupiter (Essilor Contact Lenses, Denver, CO)
Diameter:
15.6
Base Curve:
6.37
Power:
-7.00 D
Over-refraction:
Plano 20/20
Assessment:
*No blanching
*Good central vault without touching peripherally
*Well centered
Subjective: Patient extremely pleased with vision and comfort.
After his vision was checked and over-refraction was performed, fluorescein strips were wet and smeared
on his superior conjunctiva and sent out to the waiting room for thirty minutes. Upon return, DC showed
fluorescein dye in his tear lens behind the scleral lens. He was asked to return in 3 months for a follow-up
visit.
Fourth Visit:
DC was seen three months later to assess his scleral lenses. He bragged at length how comfortable his
lenses were and that he even noticed better vision than before. Additionally, he mentioned he only had to
take the lenses out once a day to clean, instead of every two hours. His eye drops now consisted of
Similasan qd-bid OU, patanol prn ou, lanolin ophthalmic ointment qhs ou, restasis qam ou. The postfitting OSDI questionnaire was filled out also, recording a 0.00 index score. He was asked to quantify
this quality of life (scale: 1 worst, 10 best) after being fit with scleral lenses and reported a 9 due to the
fact that “he still had to wear lenses for maximum vision”. Table 1 shows the pre- and post-scleral lens
fitting results. He left our clinic stating he will be getting his son fit with scleral lenses. Since then his
son has been successfully fit, has a restricted driver’s license and is employed.
TABLE 1: PRE- AND POST-SCLERAL FITTING COMPARISONS
OSDI:
Quality of Life (1-10):
Symptoms:
Medications:
*Max # of med
instillations per day:
*Mechanical Rub
Cleaning:
*Assuming 12 hr wearing
Pre-Fitting
64.6
3
Dryness
Itching
Blurred vision
Similasan (#2 Allergy)
q30min OU
Olopatadine ophthalmic
solution bid ou
Lanolin ung qhs ou
Restasis® ophthalmic
emulsion bid ou
Post-Fitting
0
9
None
Similasan (#2 Allergy) qd-bid
OU
Olopatadine ophthalmic
solution prn ou
Lanolin ung qhs ou
Restasis® ophthalmic
emulsion qam ou
29
5
q2h
q6h
DISCUSSION:
Symptoms that are common for patients with keratoconus include, frequent changes in spectacle
prescription, decreased tolerance to contact lens wear, glare.1 The author has noticed a tendency of many
patients with moderate to severe keratoconus prefer additional minus in their glasses that can be explained
by the expected contrast sensitivity reduction. Caution and awareness of this is important not to cause
near vision symptoms or headaches. Some theorize that keratoconus is the result of mechanical rubbing.4
Research has suggested that inflammatory mediators, proteins and enzymes may be in the tears. 3,5
Additionally, patients with concomitant autoimmune and allergic immune diseases may point to an
immune component in the pathogenesis of keratoconus.6 With all pubescent patients who rub their eyes
or are on anti-allergic ophthalmic drops, it wouldn’t take much to scan the cornea and perform
keratometry readings. It is important to compare central keratometry readings with readings with the
patient looking up slightly. On a typical keratometer this can be the “+” sign about an inch above the
usual target.
Many times, keratoconus is not found as a reason for decreased vision due being an early stage and not
routinely recording keratometry readings on all patients. There are some signs that are possible, but not
necessarily rules, for patients with keratoconus.1 An “oil droplet” reflex may be seen with the direct
ophthalmoscope at a distance. “Scissor” reflex with retinoscopy due to irregular astigmastism. During
the slit lamp examination, fine vertical and deep stromal striae can be seen, known as “Vogt lines or
striae”, which disappear with external pressure on the globe. A brownish or olive green “Fleisher ring”
can be seen surrounding the base of the cone indicating epithelial iron deposits.1,5 Progressive corneal
thinning up to one-third of normal thickness centrally or inferocentrally can occur resulting in both
reduction in vision and steep keratometry. “Munson sign” can be appreciated when the patient looks
down and the bulge of the cornea is outlined by the lower lid.
Most patients who are diagnosed with keratoconus will have plenty of questions regarding the disease. It
is important to instruct them what to look for and to keep in touch with you regarding their eyes. The
clinician must also know what to check during each contact lens or annual ocular examination.
Complications include acute hydrops, thinning and even spontaneous perforation. 7 Acute hydrops are
caused by a rupture in Descemet’s membrane allowing an influx of aqueous into the cornea and a drop in
visual acuity and significant discomfort and watering. Healing takes about a couple months for the breaks
to close and edema to clear. Stromal scarring may develop. Acute episodes are treated with
hyperosmotics and a soft bandage contact lens when possible. An ironic outcome may result in better
vision due to a flattening of the cornea from scarring.1
Prescription glasses are a popular option early in the disease, but with the development of irregular
astigmatism and glare, a type of contact or scleral lens would be a better option. Whereas a contact RGP
lens has at least some mechanical dynamic with the diseased cornea, a scleral lens vaults over and most
likely would be a better and more stable option. An RGP would demand increased chair time with the
need of multiple adjustments as the disease progresses, while a scleral lens could potentially last quite a
few years. Hwang, et al notes that RGP fitting with multicurve lenses is not likely to contribute to any
progression of keratoconus. It would be beneficial to have a long-term longitudinal study investigating
the long-term effects of RGPs. 8 The mode of contact lenses used varies depending on the severity of
keratoconus. The contact lens modality represents the treatment of choice in 90% of patients with
keratoconus. 2,9 Large diameter SynergEyes (3rd generation hybrid lens) allows for increased comfort and
stability of vision;10 however the scleral lens option provides even better comfort, and still allows for
great ocular health, while providing excellent vision stability. The goal of contact or scleral lenses is to
provide comfort and good vision, ultimately to delay the need for corneal surgery. Smiddy et al showed
that approximately 70% of keratoconus patients who present for surgical consideration with keratoplasty
can be managed successfully with some type of contact lenses.11 Eventually about 12-20% of the affected
patients may require some sort of surgical procedure involving replacement of at least some corneal
layers at a relatively young age. 2 Penetrating or deep lamellar keratoplasty, is indicated in patients with a
more advanced stage of keratoconus, especially with significant corneal scarring. Despite clear grafts
occurring in over 85% of cases, optical outcomes may be less than ideal by residual astigmatism and
anisometropia. These complications would best be fixed with a contact or scleral lens correction for best
acuity.1
Corneal collagen cross-linking with riboflavin and UVA (CXL) is being proven to strengthen the corneal
tissue through development of new cross-links within the collagen fibers and is only mildly invasive.
This option should be considered to potentially delay the need for lamellar or penetrating keratoplasty
while increasing the strength of the central cornea through modification of the stromal structures.12,13 At
this time the VA does not perform or provide payment for this procedure to be done.
Other procedures and surgeries that should be mentioned with keratoconus management are phakic
intraocular lenses (IOLs) and intracorneal ring segments (ICRS). Phakic IOLs are typically used to treat
lower-order aberrations of keratoconus not found to improve with contact lenses.14 After patients
underwent ICRS implantation, approximately 80% or better of them with prior contact lens intolerance
were now tolerant to wear contact lenses again.15 The attractiveness of ICRSs is that they can be
removed and different ranges can be put in. DC would not be a good candidate for ICRSs as they also
require at least 450-um of corneal thickness.
Surgical options include penetrating (PKP) or deep anterior lamellar keratoplasty (DALK). Where a
penetrating keratoplasty removes all layers of the cornea, the only portion that is not damaged with
lamellar keratoplasty is the endothelium, which is healthy in keratoconus. Kubaloglu et al. had a study
that showed long-term endothelial cell loss was moderate and lower with deep anterior lamellar
keratoplasty than penetrating keratoplasty grafts.16 PKP often produces satisfactory visual outcomes, but
it also comes with significant long-term risk of complications and many months to years of follow-up
exams.17 Fukuoka et al. had a study of 125 eyes that had PKP. They showed improvement of visual
acuity after the procedure; however, it decreased 20 years afterwards.18 Kelly et al. had a study that
showed that a repeated PKP would be more successful if the initial PKP was at least 10 years old, largely
due to episodes of inflammation of graft rejection.19 A portion of patients who have undergone PKP or
other surgical procedures end up wearing contact lenses to maximize further their visual acuity. 2
It may appear quite orthodox to not have keratometry reading or a corneal topography on a patient before
fitting scleral lenses. DC had a history of lenses, so a keratometry range could easily be assessed based
on an RGP and the staining pattern with the lens on. It must be kept in mind that the scleral lens vaults
over the cornea, so these readings are not as important as with other contact lenses. A study by
Schornack, et al had results that indicated there was no predictive relationship between topographic
indices and base curve for scleral lenses. It was suggested that a fitting paradigm based on sagittal depth
be established. 20
Many options occur with keratoconus patients, but it is essential that they are provided all options that
would best meet their expectations. With DC it appears he will be quite content with his new scleral
contact lenses for a long time. Options would be different if he started showing scarring or other
complications.
Initially, when DC was practicing removal of his scleral lens, he had difficulty. After observing his
technique of using a large diameter plunger, it was suggested to him to use a “can-opener” technique that
the author thought up. It consists of a wet plunger attached at the far nasal or temporal portion of the lens
and to twist his wrist similar to opening a tuna can or soda can tab. The patient was able to master this
technique.
The tear lens behind the scleral lens tended to accumulate debris easily that most likely originated from
the fluorescein strips. It is the author’s experience that this results in approximately a half line of visual
acuity.
All remakes of the scleral lenses were done with a change in over-refraction. Many considerations can
explain this. Jinabhai et al. showed significant changes in optical and structural parameters of the cornea
after seven days of discontinued RGP wear. This may be due to a corneal “molding” that can take place
with certain RGP fits.21 Another theory is that the over-refractive power may also have impact from how
secure or firmly the lens is placed on the eye and if there is a slight vacuum affect that arises with
increased wearing time.
CONCLUSION:
This case report represents how a content patient with keratoconus can still improve ocular symptoms and
vision with a scleral lens fit. This was proven through the decrease in ocular medications, increase in
quality of life scale, and a significant improvement in the OSDI when comparing pre- and post-fitting.
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