Refractive Status And Effects Of Surgery In Children With Oculocutaneous Albinism And Infantile Nystagmus Syndrome

Background:Oculocutaneous albinism (OCA) is a group of inherited disorders in which melanin biosynthesis is reduced or absent, which is associated with a number of visual disorders, such as iris transillumination, nystagmus, reduced visual acuity, and high refractive error and so forth. Infantile nystagmus syndrome(INS) and anomalous head posture (AHP) tend to occur frequently in patients with OCA. To our knowledge, there is a paucity of data on both the refractive status and effects of surgery of younger children with OCA and INS. A controversy towards both hyperopia and myopia can be found in a very small number of studies regarding the distribution of refractive errors. Recently, Hertle has observed that the surgery can be helpful to reduce intensity of nystagmus and improve AHP so that the foveation period which has been directly linked to patient’s visual acuity can be lengthened. Our study is aimed at describing the refractive status and effects of surgery of a clinical population of children with OCA and INS.Part Ⅰ Refractive status in children with oculocutaneous albinism and infantile nystagmus syndromeObjective:To determine the refractive status in children with oculocutaneous albinism (OCA) and infantile nystagmus syndrome (INS).Methods:Children aged under 8 years diagnosed OCA were collected between April 1,2012 and May 30,2015. The subjects were further divided into groups according to the age. Children underwent general examination, cycloplegic refraction (retinoscopy), ocular motility recordings. Refractive data were converted into spherical equivalent power (M), JO and J45 vectors for analysis.Results:Eighty-seven cases with OCA (49 males and 38 females; mean age of 2.4± 1.8 years) were enrolled in the study, which were divided into 3 groups:0-lyear; 2-4 years, and 5-8 years. Most subjects showed astigmatic refractive errors, of which compound hyperopic astigmatism and with-the-rule astigmatism were the most common. As for M,2-4 yrs group showed approximately emmetropia, whereas 0-lyear group and 5-8 yrs group both had a slight hyperopic tendency. Nystagmus was present in all participants, with horizontal pendular type (n= 36,41%) being the most common. The mean average of best corrected visual acuity (BCVA) in older subjects was 0.9±0.1 logMAR, which was much poorer than normal children. The diaphanous iris, foveal hypoplasia and poliosis were the most consistent clinical features.Conclusion:Children with OCA aged 7 months to 8 years present with the refractive status of high astigmatism, of which compound hyperopic astigmatism and with-the-rule astigmatism was the most common. Meanwhile, the normal emmetropization was impaired in OCA.Part Ⅱ Effects of surgery on children oculocutaneous albinism with infantile nystagmus syndromeObjective:To evaluate the effects of surgery for children with oculocutaneous albinism (OCA) and infantile nystagmus syndrome (INS).Methods:Children diagnosed oculocutaneous albinism (OCA) and infantile nystagmus syndrome (INS) were collected from Shandong Provincial Hospital affiliated to Shandong University between April 1,2012 and May 30,2015. The subjects underwent general eye examination and ocular motility recordings. The surgical procedure and surgical amount were designed according to type of AHP and strabismus, with or without convergence damping. The post-op follow-up was at least 3 months. Postoperative follow up included the eye position, AHP and the intensity of nystagmus. Best corrected visual acuity (BCVA) were tested for the older albinotic children before and following the surgery.Results:Eighty-seven cases with OCA and INS (49 males and 38 females; mean age of 2.4 ±1.8 years) were enrolled in the study. The mean follow-up were 13.6±12.7 months (3-41 months). Of all the participants,77 (89%) subjects had AHP, of which Chin-down position (n= 63) was the most common. Heterotropia was observed in 38 participants.26 of them were concomitant esotropia and 12 were concomitant exotropia. BCVA of older albinos increased 0.1logMAR after surgery. The AHP and intensity of nystagmus improved significantly. During 2-year follow-up period, only one patient showed a new AHP postoperatively and the second operation was performed with satisfactory effects. All strabismus patients were orthotopic postoperatively. No decrease of visual acuity was found in any patient.Conclusions:Surgery is a safe and effective method for children with OCA and INS, which could increase visual function, improve AHP and decrease the intensity of nystagmus.