“Clinical Findings, Evaluation, and Low Vision Rehabilitation of Oculocutaneous Albinism”, American Academy of Optometry: Case Report 1

 
Abstract

Oculocutaneous Albinism represents the largest segment of people who have an inherited condition known as Albinism.  Patients with albinism generally present with little to no pigment in the skin, eyes, or hair as the result of an inherited genetic inability of the body to manufacture the pigment, melanin, usually found in these tissues.  Additionally, photophobia, strabismus, nystagmus, and amblyopia, are among the other signs and symptoms often present. It is important to appreciate the challenges faced by these patients and the potential solutions and rehabilitation strategies that may be available to assist them.  This case report reviews the low vision evaluation of such a patient and the management that resulted in her ability to establish a level of visual function permitting her to be confident and efficient in almost all of the scenarios of importance to her. 

Key Words: Oculocutaneous Albinism, nystagmus, photophobia, selective therapeutic spectral filtration, autosomal recessive inheritanceP

Introduction

The word “albinism” refers to a group of inherited, (genetic), conditions that result in the absolute or partial inability of the body to manufacture the pigment Melanin.  It frequently manifests itself with the absence of pigment in the eyes, skin, and hair. Some forms of albinism, known as Ocular Albinism (OA), affect mainly the eyes with little to no involvement of the other tissues.  The other forms known as Oculocutaneous Albinism (OCA) affect the eyes, skin, and hair.

OCA is broken down into several subcategories which depend on the extent of the involvement, the racial background, and even to some extent the geographic location of the patient.  The OCA forms of the condition are far more common then the OA. The inability of the body to manufacture Melanin may result in incomplete formation of the macular tissue, a condition called foveal hypoplasia. The lack of a normal macula can manifest itself as an irregular neurological association between the eyes and the brain. 

This may be demonstrated by irregular eye movements (nystagmus), amblyopia (reduced best visual acuity in one or both eyes, usually binocular), and photophobia ( increased sensitivity to light and glare). The lack of melanin will also frequently be associated with physical findings which may include little to no pigment of the iris, retina, eyelids, eyelashes, and the rest of the body hair and skin.  Albinism may affect males and females alike and people of all races and ethnic backgrounds. There are no known cures, but there are a number of things that can be done to greatly assist people who have albinism.

Case Report

Patient #1 is now a delightful 13-year old girl originally referred by the Division of Blind services of the State of Florida.  When she first presented she was 12 years old, on May 19,2001. Her initial complaints included reduced acuity that greatly decreased her attention span and her ability to function in school, and extreme photophobia. She also suffered from headaches associated with the stress and strain she had in trying to do her school work and being unable to successfully succeed. 

She would get these headaches mainly on school days or on weekends when she would struggle to do class assignments. They seemed to cover her entire head with no localization. She didn’t like to take medications so she would generally bare with the pain until it would subside, which could be several minutes to several hour. She denied any visual aura or unusual visual disturbance associated with the headaches.  Her skin was milky white with some freckles on her arms, legs, and face.

Her head and body hair were almost white with reddish blond highlights, and her eyelashes white, completely void of pigment. The color of her irises was pinkish with a touch of blue. She never had a low vision assessment and used only single vision glasses that corrected her astigmatism. She had no history of genetic testing, and her family history was negative relative to Albinism, and the only positive finding was a maternal uncle who had adult onset diabetes.  

Her parents are both African-American. Her blood pressure was 95/68, she weighed 86 pounds, and her height was 5’1”. Her mother reported that her appetite was normal for a child her age, and that her general health was otherwise unremarkable. Additionally, it was noted that she was born with no color in her skin or hair, and that the freckles and hair color started to become apparent after the age of 3 to 4. She was quiet and a bit introverted, but didn’t suffer from depression. She was self conscious especially of her appearance, not uncommon for children and adolescents. 

Her unaided distant visual acuity was 10/100 OD and 10/80 OS.  With her present refraction of OD Pl-1.50×180 and OS Pl-1.25×180 she had acuities of OD 10/80+1 and OS 10/60.  Her manifest and cycloplegic refractions on the date of her first examination, were the same, being OD +1.25-1.25×180 and OS +.75-.50×175. Her acuities again were OD 10/80+1 and OS 10/60.   All acuities were taken with a distant Designs for Vision Feinbloom chart and in all cases her fixation was central. There was no improvement with eccentric fixation in any of the 8 cardinal positions, nor any improvement with a pinhole in either eye. 

Her nearpoint acuities were taken with a Lighthouse EDTRS chart and were as follows: OD 3.2M and OS 2.0M and OU 2.0M. She held the nearpoint card at 3” in order to see it “comfortably”. Amsler grid testing was normal in each eye as was color perception with a D-15 100 hue test.  Her tear film and tear break up time were both normal. Her corneas and anterior chambers were clear with the anterior chambers deep demonstrating a Von Herrick ratio of 1:1. She had no pingeculas or pterygia. Her pupils were normal, round, and reactive to light, and no afferent papillary defect was noted.  She demonstrates nystagmus.

The primary component of the nystagmus is pendular in nature with the fast phase to the right. The recovery phase in the horizontal meridian is almost as rapid as the fast phase. Additionally, there is a rotational component to the nystagmus with the fast phase in the counter-clockwise direction.  Motor fields were full in all directions of gaze, her head and face appeared normal, with no tilts being demonstrated in any direction.

The crystalline lenses were clear at all levels as was the vitreous. The scleras and conjunctivas were clear, but the scleras had a slight blue cast to them. The lashes were white, no pigment present, and no signs of debris at the lid margins. The irises were pinkish, with a touch of blue, and translucent especially apparent on retro illumination with the slit lamp.  She was dilated using one drop of Proparicane and one drop of .5% Mydriacyl (Light irises tend to respond adequately to lower concentrations of mydriatics and she did respond favorably affording an excellent view of the posterior pole and peripheral retina.)

The entire retinal was hypo-pigmented, and the choroidal vasculature was visible throughout the entire retina. The vasculature otherwise was normal exhibiting artery to vein ratios of 3/4. Her Elschenig classification was type I, OU, and her C/D ratio was .2 OU and the cups were shallow, appx. 1.00 diopter OU.  With the binocular indirect ophthalmoscope her macular reflexes were 5/5 OU, disc margins were crisp and clear, and no retinal holes, tears, or surface irregularities were found. Her visual fields both centrally and peripherally were full using the Humphrey field analyzer and confrontation methods of evaluation respectively.

The differential diagnoses considered in this case are all centered around Albinism.  They include:

Ocular Albinism

Tyrosinase Related Oculocutaneous Albinism (OCA1)

Classic Tyrosinase-negative Oculotaneous Albinism (OCA1A)

Yellow  Oculocutaneous Albinism (OCA1B) 

P-Gene Related Oculocutaneous Albinism (OCA2 P)

Brown Oculocutaneous Albinism

Prader-Willi and Angelman Syndromes

Hermansky Pudlak Syndrome (HPS)

Red, or Rufous or Xanthous albinism (OCA3 TRP1)

Chediak-Higashi Syndrome (CHS)

• Ocular Albinism involves only the eyes, most of the time with little to no involvement of the skin.  It is also a sex linked genetic defect carried by the females but occurs primarily in males.
• OCA1 involves the eyes, skin, and hair.  There is often a wide range of phenotypic variations associated with this geneo type. They may range from a hint of pigmentation to near normal cutaneous pigmentation, the hair is generally without pigment, but the ocular manifestations are always present.
• OCA1A likewise involves the eyes, skin, and hair, but is presented as a total absence of pigment in any of these tissues and always remains as such, with the accompanying ocular manifestations.
• OCA1B, like the OCA1 may have a wide range of cutaneous variations, but may also be exemplified by a wide range of pigment in the hair, ranging from an almost total absence of hair pigment to a full complement of hair pigment consistent with the patients genetic and familial background.
• OCA2 P commonly includes the presence of hair pigment and iris pigment at birth or very early in life. This is different from the pigmentary patterns found in the previous types, where the individual is born with no pigment in any of these tissues, and the pigment and color which they ultimately have develops within the first decade or two of life.  
• Brown Oculocutaneous Albinism is a form only recognized in African and African-American individuals.  The hair and skin color are usually light brown or tan at the time of birth and there is generally some color present in the irises as well.
• Prader-Willi and Angelman Syndromes both involve developmental complications associated with the signs of albinism, but Prader-Willi is accompanied by  hyperphagia and obesity, hypogonadism, small hands and feet and mental retardation, while Angelman Syndrome is accompanied by microcephaly, mental retardation, ataxic movements, and inappropriate laughter. 
• HPS involves the characteristic presentation of OCA1B and OCA2 but are associated with lung and gastrointestinal tract changes.  This is found all over the world, but is most commonly seen in Puerto in individuals of Hispanic ethnicity. 
• OCA3 TRP1 is an obscure form of albinism at best.  There have been a limited number of cases identified, and most of them don’t exhibit the ocular manifestations found in Albinism. 
• CHS is a syndrome that may be linked to albinism in much the same way as HPS is, but the individuals are very susceptible to bacterial infections and there is a strong presence of giant granules in their white blood cells.

This young lady was born with no pigment in her eyes, hair, or skin.  She later developed freckles and hair color which was blondish with a hint of a red tint in it.  She exhibits many of the typical ocular manifestations of Albinism; nystagmus, reduced acuity, photophobia, light translucent irises, hypopigmentation of the retina, and astigmatism. 

She is of African American descent, but her hair color isn’t close to that of her family, but the texture of her hair is consistent with her racial background and those of her parents.  She isn’t retarded, demonstrating a mental aptitude consistent with children her age, but her performance in school is below what would otherwise be predicted. She shows no signs of hydrocephaly, microcephaly, or obesity. 

Her hands and feet are of normal proportion. She doesn’t have any lung or gastrointestinal problems and isn’t prone to recurrent or chronic infections of any kind. Taking all of these considerations into account the potential diagnosis can be narrowed to two of those above, OCA1 or OCA1B. As she demonstrates some level of pigment in the hair as well as the skin it would be logical to lean toward OCA1B as the probable diagnosis. She has not undergone any genetic testing, and her mother currently refuses to permit her to do so, feeling that the information gained at this time won’t influence her future health or the means of dealing with the condition as it presently exists.  

Low Vision Evaluation:

There are 3 main goals that were addressed in working with this patient. First, to reduce the glare and light sensitivity.  Second, to improve the stability of her vision, and third to add enough magnification to permit her to function comfortably and confidently in the areas and tasks that are of both immediate and long term importance to her.  The first goal was addressed by testing her with selective spectral therapeutic filtration.

These are optical filters which selectively filter out a specific portion or portions of the visible spectrum. It has been found that certain wavelengths of light affect individuals in very distinct ways and this may vary along with the diagnosis.  Patients with many various ocular pathologies may be highly sensitive to glare and what would otherwise be normal levels of illumination.

The lenses that typically reduce the overall amount of light delivered to the patients’ eyes to provide them with comfort generally reduce the light to a level which is below that required to permit them to have enough illumination to provide the contrast and resolution they need to be able to read or function.   By utilizing lenses of specific spectral filtration, we may be able to reduce the level of glare and light sensitivity without significantly reducing the levels of contrast and impinge on the resolution that patients with reduced vision strongly need.

With this particular patient a number of different filters were tried. She was most comfortable with a lens that permitted filtration in the wavelength range of 527 nm. With this lens she felt that her vision was more stable and that she was able to see “a bit” better.  She had concerns about looking different from the other kids, and didn’t really want to wear glasses of any kind. She felt she had enough problems with her appearance without the lenses. Her school doesn’t permit students to wear sunglass in class, but her lenses aren’t sunglasses, they are therapeutic spectral filters. With this in mind a pair of glasses was made for her that integrated the filters. 

Various forms of magnification were also evaluated at this time.  With a magnification of 2X at nearpoint using a clear image II microscope with her distant prescription integrated into the system she was able to read .8M continuous print with relative ease and function. With 3X distant magnification in the form of a focusable spiral Galilean telescope she was able to attain a distant acuity of 10/20-1 OS.  The same distant function was obtained using a ½” Edwards front focusable bioptic telescope. We therefore integrated bifocals into the initial pair of glasses utilizing a flat top 28 mm segment and a +6.00 add. The lenses were tinted using a 527 corning filter. The reasoning again was to see how she would respond to magnification, the segment, and the appearance of the glasses.

The glasses were dispensed on April 2, 2001.

Follow up #1

When she returned on April 30 for a follow-up consultation she reported that her the frequency and severity of her headaches had decreased and that she was able to pay attention better in class than she had before.  She also said her sensitivity to bright light and glare was almost gone, and that the glasses were “really cool”. She didn’t mind wearing them and the other kids wished they could wear tinted lenses in school. She felt special.  Her mom also reported that her ability to read and concentrate had improved substantially, but that she was still having trouble viewing the board.

We had requested authorization from the Division of Blind services for a low vision device that consisted of a 3x ½” telescope fit  Edwards telescope fit in the bioptic position OS along with 2X clear image type E microscopes integrated into the lenses OU. The lenses were to be tinted with the Corning 527 equivalent tints, and integrated in the microscopes as well as the ocular of the telescope.

Additionally 5 prism diopters base in was added in the microscopic segments to aid in the relief of convergence at her 6” to 8” reading range.  We weren’t able to obtain enough funding to produce this device through DBS. They were able to contribute a portion of the funds needed and we applied to the American Foundation for Visual Rehabilitation.

Between the two sources we had enough funds to produce the device but had to substitute the more cosmetically acceptable Edwards scope for the 3X Designs for Vision spiral Galilean telescope. We talked about the advantages and disadvantages of this system and she was still willing to give it a try.  Appropriate measurements were taken and the device ordered.

Follow up #2

We again saw her on  May 21, 2001 to dispense her device.  She continued to report the same levels of comfort and function with the 527 bifocal glasses.   At the time of dispensing she worked with one of our occupational therapists to familiarize her with the new device and its function.  She was taught how to focus the telescope and instructed in its use.

A series of exercises was demonstrated that would help her in sighting distant targets through the intermediate distant rx, and then translating into the telescope to permit the target to be in the field of view of the scope when its’ use was called upon.  She was also given exercises that would improve her tracking and the co-ordination of versions through the telescope to assist her in reading the board in school. She was given a plan utilizing these exercises at home on a daily basis to improve her facility and function.  

Follow-up #3

On May 28, 2001 she returned for further assessment of her ability to function with her new device.  Despite its appearance she was happy with it. Her peers had accepted it and no one had teased her about it.  She was able to follow most of the things that were going on in the front of the classroom with the telescope and reported that her nearpoint and reading functions were very good with the microscope.  She had no problems with headaches at all when wearing the device and no symptoms related to glare. Her nystagmus appeared to be the same objectively with or without the scope, but she reported that subjectively her vision was more stable and comfortable with the device.  

Follow-up #4

On November, 2001 she continues to be very happy with the device.  Her acuities remained stable, with and without the device, and her headaches have disappeared. She no longer complains of glare sensitivity.  Her performance in school has gone up a complete grade level, and she is now performing much closer to her potential. Her mother and teachers are very pleased with the quality of her work and especially with the change in her attitude and classroom participation.

Annual Follow-up Examination

On April, 2003 she returned for her annual examination.  There were no changes in her personal or family health histories in the preceding year.  She had no new subjective complaints, but did continue to report the great pleasure she derived from the device.  Her mother continued to report scholastic success and no significant problems with headaches or glare. All findings relating to both internal and external ocular examination were stable and in line with those of March of 2002.  Her refraction had changed by +.25 sphere OD and no change was noted OS. No changes were made at that date and she is due to be re-evaluated in April of 2005.