皇家华人

HPI:
An 8-year-old male patient presents with mother of child to general ophthalmology clinic. Patient and mother served as independent historians. He has not been seen by an ophthalmologist or optometrist before but has been having vision checks at school and sees his pediatrician every couple of years. Mother reports that for the last 6 months her son has been complaining of difficulty seeing the whiteboard at school. Patient reports that the light sometimes makes his eyes water. Mom has not noticed any eye crossing or eye wandering, but does note his eyes move back and forth at times, worse when he is tired. According to mom, other than noting difficulty seeing the board at school, patient’s vision does not seem to prevents him from playing with friends or doing any other activities.

Past Ocular History:
None

Ocular Medications:
None

Past Medical History:
Born at 39 weeks without complications
Frequent ear infections prior to ear tubes

Surgical History:
Bilateral ear tubes at age 2

Past Family Ocular History:
No history of blinding diseases, glaucoma or macular degeneration

Social History:
Lives at home with mom and dad. No smoker in home. Currently in 3rd grade.

Medications:
None

Allergies:
No known drug allergies

ROS:
Denies recent illness or any new CNS, heart, lung, GI, skin or joint symptoms.


Ocular Exam

Visual Acuity (cc):
OD: 20/50
OS: 20/50
Visual acuity OU improves to 20/40 with pinhole and refraction

IOP (iCare tonometry):
OD: 16 mmHg
OS: 17 mmHg

Pupils:
OD: Equal, round and reactive to light in dark and light settings, no APD
OS: Equal, round and reactive to light in dark and light settings, no APD

Extraocular Movements:
OD: Full. Mild nystagmus noted at distance and at near.
OS: Full. Mild nystagmus noted at distance and at near.
No anomalous head posture or strabismus noted.

Confrontational Visual Fields:
OD: Full to finger counting
OS: Full to finger counting

Slit Lamp Exam:

OCT Imaging:
Image demonstrates lack of normal foveal contour due to foveal hypoplasia

Fundus Photo:
Image demonstrates lack of foveal light reflex and blonde fundus.

Image references: Patient JC_12565 seen at AOIP with known ocular albinism diagnosis.

• The patient is presenting with reduced visual acuity, nystagmus, photophobia, blonde fundus and blunted foveal light reflex on dilated retinal exam, and foveal hypoplasia on OCT, consistent with ocular albinism
• Further workup could include genetics testing to look for a mutation in the GPR143 gene
• Treatment: There is no cure for ocular albinism. Further treatment includes maximizing best corrected visual acuity and providing access to low vision resources

• Refractive error is decreased visual acuity caused by myopia (nearsightedness), hyperopia (farsightedness), astigmatism
• Refractive error is likely present because vision improves with pinhole, but it does not improve to 20/20 with pinhole
• Treatment: Refractive error can be treated by a wide range of modalities from simple glasses to invasive LASIK surgery

• Signs of dry eye would be seen on exam, history of visual symptoms such as blurriness that improves with blinking
• Dry eye can be caused by various etiologies, most commonly meibomian gland dysfunction
• Treatment: Artificial tears and warm compresses

• Strabismus is eye misalignment that can cause decreased visual acuity and is often diagnosed in childhood
• However, eye crossing or eye wandering would be seen on extraocular movement portion of exam
• Treatment: Strabismus can be treated with glasses and possible surgery on the eye muscles to re-align the eyes

• Amblyopia, which is decreased visual acuity due to abnormal visual development, can be refractive, strabismic, deprivation or structural
• However, amblyopia is often in one eye and not bilateral
• Treatment: Patching or atropine of the better seeing eye

• Infantile Idiopathic Nystagmus is a diagnosis of exclusion, when patients have nystagmus with no clear underlying cause
• Our patient does have nystagmus, but also has signs of albinism with blonde fundus and foveal hypoplasia
• Treatment: There is no cure for Infantile Idiopathic Nystagmus. Sometimes surgery on the eye muscles can help control nystagmus

Definition:
Ocular albinism (OA) is caused by an X-linked mutation in the GPR143 gene. Because of its X-linked inheritance, OA is more common in males compared to females. In OA the retina and choroid have altered melanosome biogenesis and transport that results in a hypopigmented appearance, but the skin and hair appear to have normal coloration. Altered melanin biosynthesis is associated with incomplete foveal development and can cause other related conditions such as strabismus, amblyopia, nystagmus, low visual acuity, and photophobia.

Examination:
Ocular albinism can be difficult to diagnose because skin and hair changes are not visible to the naked eye the way that they are with oculocutaneous albinism types. However, physical exam signs can include reduced visual acuity, nystagmus, strabismus, and a blonde fundus. On fundus imaging you may see absent foveal light reflexes, while OCT imaging will reveal foveal hypoplasia. Other clues will come from history of similar presentation in other male family members, but no female family members. Female carriers will show an abnormal retina on autofluorescence imaging (NIR or short wavelength) due to X-inactivation mosaicism.

Treatment:
There is no cure for this genetic disease. The patient should be seen regularly to maximize vision and protect the eyes as much as possible. Visual acuity can be improved with glasses correcting for refractive error and use of magnifying glasses. Surgery can be done for strabismus if any is present. Patients should be connected with a genetic counselor and low vision clinics or local organizations that can provide supplies such as magnifying glasses, computerized dictation programs, large print books, etc. These organizations may also hold workshops and educational sessions about living with low vision to maximize the patient’s quality of life.

What are the typical signs and symptoms in patients with ocular albinism?
a. Retinal transillumination
b. Reduced visual acuity
c. Nystagmus
d. All of the above

How should patients monitor their vision for the development of changes associated with ocular albinism?
a. Have parents perform weekly visual acuity testing
b. Patch different eye every other day to make sure the patient is using both eyes
c. Have regular vision checks at annual pediatrician visits and pay attention to any concerns from teachers
d. Wait until the patient turns 18 to see optometrist/ophthalmologist

What are the typical signs and symptoms in patients with ocular albinism?
d. All of the above

Ocular albinism can cause a variety of symptoms including all of the above.

How should patients monitor their vision for the development of changes associated with ocular albinism?
c. Have regular vision checks at annual pediatrician visits and pay attention to any concerns from teachers

It is important to have regular doctor visits where visual acuity testing is performed. Some schools will also have annual vision screenings, but this may not be the case at every school. Finally, it is important to note if the child or his teachers have any concerns about seeing, which is most evident when reading books up close or the whiteboard at a distance in school.

References/Resources:

1. Albinism: Types, Symptoms and Causes. Cleveland Clinic. Accessed October 23, 2023.
2. Infantile Idiopathic Nystagmus: for Professionals. Gene Vision. Accessed October 23, 2023.
3. Low Vision Services. Vision Forward. Accessed October 23, 2023.
4. Ocular Albinism: MedlinePlus Genetics. Accessed October 23, 2023.
5. Types of Amblyopia. American Academy of Ophthalmology. Published October 21, 2015. Accessed October 23, 2023.
6. Welcome to NOAH. Accessed October 23, 2023.