Abstract
Abstract: :
Purpose:Hermansky–Pudlak Syndrome (HPS) is a form of oculocutaneous albinism, associated with bleeding diathesis. Although it is known that HPS patients exhibit nystagmus, eye movements in HPS have not been systematically studied. Methods:Twenty patients with genetically confirmed HPS are included. All had a systemic evaluation, complete eye exam, and eye movement recordings, using magnetic search coil, or infrared or video–oculography. Results:Patients had iris transillumination, foveal hypoplasia and variable degrees of hypopigmentation. Visual acuities ranged from 20/25 to 20/320. Sixteen patients had strabismus, in spite of prior strabismus surgery in seven of them. Nystagmus was clinically evident in all but three patients. Eye movement recordings revealed abnormalities in all patients. The most common nystagmus type was periodic alternating nystagmus documented in 11 patients. Three patients without clinically evident nystagmus showed square–wave jerks, fixation instability, and minimal end–gaze nystagmus. They had better visual acuities and posterior pole pigmentation than the other patients. Conclusions:HPS patients exhibit variable degrees of hypopigmentation and may have no clinically evident nystagmus. Assessment of eye movements may assist the diagnosis and alert the clinician to the potential for bleeding during strabismus surgery. Absence of clinical nystagmus in a child with HPS indicates good visual prognosis.
Keywords: nystagmus • eye movements: recording techniques • genetics