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Pellucid Marginal Corneal Degeneration – Take Two!
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: Pellucid marginal corneal degeneration (PMCD) is a rare, bilateral, slowly progressive, peripheral corneal
thinning disorder that presents in the fourth to fifth decade.1 Case Report: This case report shows a patient with PMCD
who had poor vision even with his rigid gas permeable (RGP) contact lenses. He also had some dry eye symptoms as well
as allergic conjunctivitis from seasonal allergies. Conclusion: He was successfully fit with scleral lenses which not only
significantly improved his vision, but also eliminated his dry eye symptoms.
Key Words: Pellucid Marginal Corneal Degeneration, rigid gas permeable contact lens, scleral lens
INTRODUCTION:
Pellucid marginal corneal degeneration (PMCD) is a rare, bilateral, slowly progressive, peripheral corneal
thinning (up to 80% stromal tissue loss) disorder that presents in the fourth to fifth decade.1,2 The inferior
cornea is most often involved although rarely the superior cornea may be involved.1 The thinning is
always clear, avascular, epitheilialized, and without lipid deposits.3 At present, the exact etiology,
incidence and prevalence are unknown.2 Additionally, there is no evidence PMCD is genetically
inherited.2 Despite the slow progression of this disease, it can have devastating complications. Lee, et
al4 had a case report showing bilateral corneal perforation. Scleral injection, acute pain, a sudden
reduction in vision and photophobia would indicate an immediate examination in the clinic.2
CASE REPORT:
DW is a 66 year-old African American veteran presenting to the WJB Dorn VA Medical Center
optometry contact lens clinic for options to improve his slowly failing vision. He was referred from our
disease clinic after his ocular health examination, including a dilated fundus examination.
Systemic diseases/complications and mode of treatment:
Problem:
Medicine:
Alcohol dependence
Asthma
Formoterol Furamate
Mometasone Furoate
Complete rupture of rotator cuff
Degenerative disc disease
Spinal stenosis
Pellucid marginal corneal degeneration
Environmental allergies
Gout
Hearing loss, partial
Hypertension
Hypertriglyceridemia
Posttraumatic stress disorder
Spinal stenosis
Erectile Dysfunction
Hypokalemia
Multivitamin
Albuterol
Ibuprofen
“
“
RGPs
Loratadine
Ketotifen
Allopurinol
Bisoprolol
Niacin
Citalopram Hydrobromide
Calcium/Vitamin D
Vardenafil
Potassium Chloride
Thiamine
Omega-3 Polyunsaturated Fatty
Acids
Multivitamin
First Visit:
DW had a history of poor vision with a long history of wearing contact lenses. He was seen a few years
ago in our contact lens clinic, when he was successfully fit with the following large-diameter rigid gas
permeable (RGP) contact lenses:
Habitual contact lens parameters:
OD:
Material
Boston XO2 LD Fenestrated
Diameter
14.00
Base Curve
6.75
Power
-5.25 D
Assessment:
*Diffuse deposits
*Movement on push-up test – very little on blink
*Centered
OS:
Material
Diameter
Base Curve
Power
Boston XO2 LD Fenestrated
14.00
7.03
-4.00 D
Assessment:
*Diffuse deposits
*Movement on push-up test – very little on blink
*Centered
Entering visual acuity:
20/40+2
20/50+
with habitual contact lenses
Habitual glasses prescription:
OD: +0.25-3.75x057
OS: +2.50-6.00x115
Corneal Topography:
+2.50 Progressive Add Lens (PAL)/Transitions/High Index
(from previous contact lens fitting)
His anterior segment examination appeared unremarkable OU, except for some diffuse corneal staining
OU. His previous dilated examination showed no other ocular health concerns.
When evaluating him to determine if he would be a successful scleral contact lens patient, he showed
determination and desire. He admitted having dryness symptoms and vision seems to be increasingly
getting worse. Both of these factors, along with a history of contact lens wear, made DW an excellent
candidate to be fit for scleral contact lenses.
The initial trials were inserted with fluorescein strip coloring the fluid and allowed to settle for
approximately thirty minutes. The patient was instantly impressed with the comfort. The visual acuity
was impressive too once the over-refraction was determined.
Initial Fitting:
OD:
Jupiter (Essilor Contact Lenses, Denver, CO)
Diameter:
15.6
Base Curve:
6.75
Power:
-10.00 D
Over-refraction:
+4.25 D 20/30-2
Assessment:
*Slight blanching superiorly
*Good central vault
*Centered
*No corneal touch
Subjective: Patient was able to feel edge superonasally
OS:
Jupiter (Essilor Contact Lenses, Denver, CO)
Diameter:
15.6
Base Curve:
7.03
Power:
-8.00 D
Over-refraction:
+3.50 D 20/25+2
Assessment:
*No blanching
*Edge good
*Not enough central vault
*Centered
*No corneal touch
First Order:
The lens was ordered and DW was informed he would receive a telephone call when the lens arrived to
schedule an appointment.
Second Visit:
At the follow-up appointment, the lenses were inserted with fluorescein strip coloring the fluid and
allowed to settle for approximately thirty minutes.
OD:
Jupiter (Essilor Contact Lenses, Denver, CO)
Diameter:
15.6
Base Curve:
6.89
Power:
-4.75 D
Over-refraction:
-0.50 D 20/20Assessment:
*No blanching
*Good central clearance
*Centered with no corneal touch
OS:
Jupiter (Essilor Contact Lenses, Denver, CO)
Diameter:
15.6
Base Curve:
6.89
Power:
-5.50 D
Over-refraction:
-0.25 D 20/20-2
Assessment:
*No blanching
*Good central clearance
*Centered with no corneal touch
The patient was given a peroxide based cleaning system and was educated how to use it properly. He also
was instructed to pick-up 0.9% sodium chloride inhalation solution (off label use) at the VA pharmacy
window to use 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 to wear until the next visit. The slight
change in the over-refraction was made and the patient was called for the next appointment when his next
pair of lenses arrived.
Second Order:
Third Visit:
At the next follow-up appointment, the previous lenses were already inserted and had been in his eyes for
approximately four hours prior to the visit. The patient complained of a “film over his vision” since he
was at the clinic last.
OD:
Jupiter (Essilor Contact Lenses, Denver, CO)
Assessment:
*No blanching
*Good central clearance
*Centered with no corneal touch
*Waxy appearance to lens which did not allow the lenses to wet properly
Subjective: Film over his vision
OS:
Jupiter (Essilor Contact Lenses, Denver, CO)
Assessment:
*No blanching
*Good central clearance
*Centered with no corneal touch
*Waxy appearance to lens which did not allow the lenses to wet properly
Subjective: Film over his vision
The previous lenses were removed and the new lenses with the over-refraction change were inserted.
OD:
Jupiter (Essilor Contact Lenses, Denver, CO)
Diameter:
15.6
Base Curve:
6.89
Power:
-5.25 D
Over-refraction:
Plano 20/20Assessment:
*No blanching
*Good central clearance
*Centered with no corneal touch
Subjective: Great vision and comfort
OS:
Jupiter (Essilor Contact Lenses, Denver, CO)
Diameter:
15.6
Base Curve:
6.89
Power:
-5.75 D
Over-refraction:
Plano 20/20Assessment:
*No blanching
*Good central clearance
*Centered with no corneal touch
Subjective: Great vision and comfort
After assessing the fit, fluorescein strips were wetted and smeared over each superior conjunctiva. The
patient was sent out to the waiting room to allow the lenses to settle approximately thirty minutes. Upon
return, assessment of the lenses showed that the fluorescein had entered the fluid behind the lens in each
eye. The patient was given the lenses to take with him. He denied any trouble with insertion and
removal. He stated he complied with the cleaning regimen. Regarding the “film over his vision” and the
waxy appearance of the lenses, he was asked about washing his hands prior to inserting his lenses. He
mentioned that he always washed his hands before insertion of his lenses. He was further asked about
any type of lotion, moisturizer or after-shave lotion prior to inserting his lenses. The patient admitted
putting a moisturizing lotion on after getting out of the shower, and therefore before he inserted his
lenses. The patient was encouraged to put his lenses in prior to the moisturizing lotion and was further
given Boston Simplus TM Mulitple-Action Solution (Polymer Technology, a Bausch & Lomb company,
Rochester, NY) to manually rub and clean the inside of the lens if a film continued to develop on the
lenses.
Follow-up Phone Call:
Due to the DW living a significant distance from our clinic, a phone call was used to follow-up after
approximately four months. The patient admitted wearing his scleral lenses every day of the week from
approximately 10:00am to 11:00pm. He notices no discomfort or decreased vision with this long wear
time. His dryness symptoms have been resolved completely. He also mentioned that the cleaning
recommendations he was given last visit was working well and he no longer had a “film over his vision.”
The patient agreed to contact us if there were any problems, questions or concerns.
DISCUSSION:
During the fitting of DW for scleral lenses, it became evident more information was necessary to discover
the cause of his “film” and how to prevent it in the future. The author relied on his past experience with
similar occurrences. Oftentimes it is a special soap, anti-bacterial hand gel or moisturizing lotion. If the
patient was female, questions regarding standard make-up practices would be asked. The patient was
previously placed on a hydrogen-peroxide cleaning regimen. This is great for the average scleral lens
patient. Those with make-up or lotion issues also need to use a digital cleaner to assist in preventing a
build-up on the lenses, especially the inside portion of the lens.
Clinically the only signs that can be noticed in PMCD are corneal thinning inferiorly about 1mm from the
limbus (4:00-8:00 region), flattening in the vertical meridian resulting in severe irregular against-the-rule
astigmatism, and the epithelium is intact with the cornea above the thinned out area being ectatic.1 A
side view may show the contour of a “beer-belly”.2 No Fleischer rings or Vogt striae occur, and acute
hydrops are possible, but very rare complications.1 The only diagnostic test is a corneal topography
showing a “crab-claw”, “butterfly” or “kissing doves” pattern associated with severe astigmatism and
diffuse steepening of the inferior cornea.1,2
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 RGP contact
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. Surgery is not the best option for these patients and is typically performed on PMCD patients
only if they develop contact lens intolerance. Regarding penetrating keratoplasty (PKP), 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 Deep anterior lamellar keratoplasty has shown to be a better surgical option with a faster
recovery time. Other surgical options, although none are ideal, are large thermocuteriation, crescentic
lamellar keratoplasty, wedge resection of diseased tissue, and epikeratoplasty.1 A 210o arc length
intrastromal corneal ring segment (ICRS) has been reported to be beneficially improve visual acuity and
glare by strengthening the area that has thinned.5 Tzelikis, et al3 performed a retrospective chart review
of forty-five patients with PMCD and found that over 88% were managed nonsurgically. Most surgeries
were generated due to contact lens intolerance. The intralimbal RGP was typically used for this study.3
With the rise of scleral lens fitting, it wouldn’t be surprising to see that more patients with PMCD are
managed with the nonsurgical option of scleral lenses due to the significant comfort when compared to
the average RGP lens.
CONCLUSION:
This case report shows a patient with PMCD who had poor vision even with his RGP contact lenses,
some dry eye symptoms, and allergic conjunctivitis from seasonal allergies. He was successfully fit with
scleral lenses which not only significantly improved his vision, but also eliminated his dry eye symptoms.
Visual acuity quantitatively improved from20/40+2 OD and 20/50+ OS and now 20/20 is reached in both
eyes. With this vision and elimination of symptoms, DW most likely will avert any type of corneal
surgery for the rest of his life.
REFERENCES:
1. Kanski J. Clinical ophthalmology: a systematic approach. 6th ed. Edinburgh; New York:
Butterworth-Heinemann/Elsevier; 2007.
2. Jinabhai A, Radhakrishnan H, O’Donnell C. Pellucid corneal marginal degeneration: A
review. Contact Lens and Anterior Eye. 2011 Apr;34(2):56-63.
3. Tzelikis PF, Cohen EJ, Rapuano CJ, Hammersmith KM, Laibson PR. Management of
pellucid marginal corneal degeneration. Cornea. 2005 Jul;24(5):555-560.
4. Lee WB, OʼHalloran HS, Grossniklaus HE. Pellucid Marginal Degeneration and Bilateral
Corneal Perforation: Case Report and Review of the Literature. Eye & Contact Lens: Science
& Clinical Practice. 2008 Jul;34(4):229-233.
5. Kubaloglu A, Sari ES, Cinar Y, Koytak A, Kurnaz E, Piñero DP, et al. A Single 210-Degree
Arc Length Intrastromal Corneal Ring Implantation for the Management of Pellucid
Marginal Corneal Degeneration. American Journal of Ophthalmology. 2010 Aug;150(2):185192.e1.