Retina Case: “External Pallor” Kevin Lowder, MD – PGY3 03/01/2019

Patient Presentation CC HPI Difficulty driving at night 21 yo WF with hx of mild nystagmus OU, p/w difficulty driving at night and light sensitivity. Pt was referred to retina by outside ophthalmology practice for suspected retinal dystrophy given abnormal exam and OCT findings.

History (Hx) Past Ocular Hx: Nystagmus OU Ocular Meds: none PMH: Migraines, HTN, IBS, Anxiety Fam Hx: Non-contributory Meds: Linaclotide, Zonisamide, birth control Allergies: NKDA Social Hx: Never smoker, no EtOH or drugs RoS: Negative Linaclotide = for IBS Zonisamide = anti-convulsant 3

Physical Exam OD OS BCVA 20/30 20/50+2 Pupils 4mm. Round. Brisk. No rAPD IOP 14 mmHg 15 mmHg EOM full CVF Adnexa Small amplitude nystagmus

Physical Exam SLE OD OS External/Lids WNL Conj/Sclera White, Quiet Cornea Epithelium intact Ant Chamber Normal depth, Quiet Iris subtle transillumination defects Lens clear

Posterior Exam (Fundus Photos)

OCT Macula: Foveal Hypoplasia OU Foveal cut OD Foveal cut OS

Assessment 21 yo WF with ocular albinism Albinoid external appearance Light sensitivity Nystagmus Foveal hypoplasia Iris transillumination defects Suboptimal BCVA

Other Features: Abnormal decussation of the visual pathways Normal ~53%; in ocular albinism can be 90% Strabismus/loss of stereopsis  related to abnormal decussation Can be tested with VEP Photophobia Refractive errors (myopia, hyperopia, astigmatism) Poor vision (ranging from mild to < 20/200)

Main Subsets of Albinism Oculocutaneous: AR inheritance Tyrosine-positive: gradually accumulate more pigment Tyrosine-negative: do not Chédiak-Higashi syndrome: neutropenia/blood disorder that leads to deadly infections and bleeding Hermansky-Pudlak syndrome: platelet defect that causes easy bruising and bleeding (3 P’s: Pigment-less, Platelets, Puerto Ricans) Ocular albinism: X-linked (most common) True albinism: fovea is hypoplastic, BCVA is decreased Albinoidism: (AD) foveal pit is present, VA normal, no nystagmus Albinoidism = AD with incomplete penetrance

Treatment/Plan Observe/treat symptoms Consider genetics consult Hematology consult if any suspicion for blood disorders

References Kim, JM. (2014, December). Albinism. Retrieved from http://eyewiki.aao.org/Albinism. 2017-2018 Basic Clinical Sciences Course, Section 12: Retina and Vitreous. American Academy of Ophthalmology, 2017. Pages 247-8