Download Gulmiri, A

When ‘eye’ move, you move: Scleral lenses in a case of oculocutaneous albinism-induced
nystagmus
By: Anita Gulmiri, OD
I. Case History:
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15 year-old white male with congenital oculocutaneous albinism complains of blurry
vision with current spectacles, nystagmus, and a secondary complaint that eyes do not
stay open / squinting with current spectacles.
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Date of initial exam: 07/23/15, date of CL fitting: 08/13/15, date of lens pick up and eval:
08/27/15
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Medical History: oculocutaneous albinism, no medications and no allergies
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Ocular History: high hyperopia, high astigmatism, nystagmus, accommodative esotropia,
and amblyopia, photosensitivity when outdoors. Previous history of failure with soft toric
contact lenses, and small diameter RGP lenses.
II. Pertinent Findings
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Entering visual acuity with current spectacles was 20/400 OD and OS with a 20Δ
intermittent and variable right accommodative esotropia. Corneal topography shows
simK: OD :42.60/46.11@165 and OS: 39.94/43.65@086, however imaging was unstable
due to patient’s nystagmus. Final Spec RX was OD: +4.50-6.00x020 (VA 20/400) and
OS: +4.50-6.00x165 (VA 20/400) Slit lamp examination reveals complete poliosis of
eyebrows and eyelashes OU, clear cornea OU, iris transillumination defects 360 OU,
and foveal hypoplasia OU.
III. Diagnosis:

Oculocutaneous albinism causing nystagmus, high astigmatism and high hyperopia,
strabismus, amblyopia and photosensitivity (most bothersome when outdoors).

Differential Diagnosis: Various contact lens options were considered including higher
modulus soft toric contact lenses which could provide better stability, bitoric small
diameter gas permeable lenses, custom-tinted soft toric contact lenses for
photosensitivity, and possibly surgical options (limbal relaxing incisions to reduce
astigmatism). Ultimately, scleral lenses were chosen to minimize invasiveness, protect
ocular surface, provide stability and maintain comfort.
IV: Diagnosis and Discussion
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Oculocutaneous albinism is an inherited condition that affects the pigmentation of the
eyes, skin, and hair (5). It is a rare condition affecting only 1 in 17,000 patients (1,5).
Patients with this condition have reduced distance vision, rapid, involuntary eye
movements (nystagmus) and increased sensitivity to light due to reduced pigmentation
of the iris and macula. Patients also usually have highly visible choroidal vasculature due
to retinal hypopigmentation (3). Best-corrected visual acuity may range from 20/40 to
20/400 depending on the severity of condition. Some patients may also have strabismus,
secondary amblyopia, and therefore reduced stereopsis (2). Nystagmus begins at age 23 months and usually remains constant and stable throughout life. External signs and slit
lamp findings include depigmentation of eyebrows, eyelashes, iris transillumination
defects, and hypoplastic foveae.
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A quality of life survey for patients with albinism revealed that a 100% of patients with
albinism experience blurred distance vision with best correct spectacles, 60% have
difficulty watching TV and 50% have difficulty crossing the road alone. Patients with
albinism suffer overall from a lower quality of life due to reduced vision at distance and
glare (7). Contact lenses may serve to improve quality of life for patients with nystagmus.
(2)
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Due to the patient’s high refractive error and nystagmus, vision is not optimal with
spectacles. Previously unsuccessful with soft toric contact lenses (due to lack of stable
vision with variable lens rotation) and intolerant to small diameter corneal GP lenses
(due to lack of comfort and decentering lens), per patient’s mother. Large diameter RGP
lens were chosen to provide comfortable, stable, and optimal vision.
V: Treatment, management
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New CL fit with Valley Contax (Springfield,OR,USA), Custom Stable Elite scleral lenses
○
OD BC 8.23/+4.00/sag 3.66 and dia 14.8, BOSTON XO, toric PCs
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OS BC 8.23/+3.25/sag 3.66 and dia 14.8 BOSTON XO, toric PCs
○
Custom Stable Elite chosen vs Custom Stable to provide scleral alignment due to
high corneal cyl contributing to toric scleral anatomy.
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Vision improves from 20/400 (spectacles) to 20/100+ OD/OS with scleral lenses with
potential of visual acuity improving to 20/80 with an over-refraction. The benefits of
contact lenses vs. spectacles can be explained by the idea that nystagmus decreases
due to increased vergence and accommodative effort with contact lenses. Additionally,
lenses improve vision in patients with nystagmus by maintaining alignment with optical
axis, since lens moves with eye movements (4).
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In a report by Biousse et al, it was concluded that all patients preferred contact lenses
over spectacles with an improvement in contrast sensitivity with contact lenses than with
spectacles alone (2).
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Although small diameter gas permeable lenses would have provided similar
improvement in visual acuity, scleral lenses have the added benefit of comfort. One
study Lahnstein et al did argue that small diameter GP lenses may dampen nystagmus
due to tactile feedback from GP lens edge awareness (4).
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Children may not be ideal for scleral lenses due to small aperture size and possible
difficulty with insertion, removal and lens care. However, in this case, the benefits of
increased comfort and vision outweigh the potential hurdles.
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While objectively, there is a modest improvement of visual acuity, there is a marked
improvement in the quality of vision experienced by the patient. After being fit with
scleral lenses, patient reports this is the best his vision has ever been, he is able to
discern details on buildings and see features on mother’s face for the first time. He also
feels his eyes do not move as much because he’s able to focus better when lenses are
on vs. spectacles.
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Mother notices patient is able to keep his eyes open when scleral lenses on vs. when
patient is wearing spectacles. While this is an unusual outcome, the plan moving forward
at the next follow up visit is to measure aperture size with specs vs. with scleral contact
lenses to measure objective difference. If significant change in aperture size, explore
possible reasons for the difference.
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Other treatment and follow up plans include sunglasses to control photosensitivity when
outdoors, improvements in overall fit of scleral lenses to possibly further improve visual
acuity, re-measure visual acuity with low vision charts and/or contrast sensitivity charts
for more precise visual acuities.
VI: Conclusion
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Individuals with oculocutaneous albinism suffer many visual disturbances, such as
nystagmus, high refractive error, strabismus, amblyopia, and photophobia. Management
of these patients is geared towards improving quality of life. When common treatment
options such as spectacles, soft toric contact lenses, or small diameter GP lenses are
not successful, a scleral lens can provide improvements in visual acuity while
maintaining comfortable and functional vision.
●
Scleral lenses vault the cornea to mask high corneal astigmatism and move with the
eyes to maintain alignment with the optical axis to increase visual potential for patients
suffering from nystagmus
●
Although fitting large diameter gas permeable lenses can more difficult with children due
to their limited experience with contact lens handling and care, it should not be ruled out
when the benefits outweigh the possible difficulties.
References:
1. Blachford SL A: The Gale Encyclopedia of Genetic Disorders. Gale Group-Thompson
Learning, Detroit, MI; 2002.
2. Biousse, V., R. J. Tussa, B. Russell, M. S. Azran, and V. Das. "The Use of Contact
Lenses to Treat Visually Symptomatic Congenital Nystagmus." J Neurol Neurosurg
Psychiatry (2004);75:314-316. Web
3. Ehlers, Justis P., and Chirag P. Shah. "Albinism." The Wills Eye Manual: Office and
Emergency Room Diagnosis and Treatment of Eye Disease. Philadelphia: Lippincott
Williams & Wilkins, 2008. N. pag. Print.
4. Lahnstein, Carrie, Harold Bedell, and Karen Fern. "Improved Visual Acuity And
Decreased Eye-Movement Intensity In A Patient With Nystagmus During RGP Lens
Wear." Optometry and Vision Science 78.SUPPLEMENT (2001): 155. Web.
5. "Oculocutaneous Albinism." Genetics Home Reference. US National Library of Medicine,
24 Aug. 2015. Web. 25 Aug. 2015.
6. Okulicz JF, Shah RS, Schwartz RA, Janniger CK. Oculocutaneous albinism. J Eur Acad
Dermatol Venereol. 2003 May;17(3):251-6. Review.
7. Omar, R., S. S. Idris, C. K. Meng, and F. V. Knight. Management of Visual Disturbances
in Albinism: A Case Report. Rep. N.p.: n.p., n.d. J Med Case Reports, 19 Sept. 2012.
Web.