Purpose: To quantify retinal function longitudinally and crosssectionally in p atients with autosomal-recessive early-onset severe retinal dystrophy (EOSRD) associated with RPE65 mutations. Subjects and methods: The ocular phenotype was characterized in four children from three families up to the second decade of li fe, and in three siblings from one family aged 43-54 years carrying compound he terozygous or homozygous mutations in RPE65. Standard clinical examination inclu ded colour vision testing, fundus photography and Goldmann visual fields (GVF). Full-field ERGs (in all) and multifocal ERGs (in two patients) were also record ed. Visual performance and fundus appearance were compared to literature data. R esults: In childhood, visual acuity (VA) ranged from 0.1 to 0.3, and GVF for tar get V4 was well preserved. VA and GVF were measurable in only one of the three a dult siblings. Nystagmus was present in two of four children and two of three ad ults. Photophobia was absent in childhood and developed in adulthood. Funduscopi c changes were discrete during the first decade of life in three of four childre n; one patient had clear macular changes already at age 5 years. All three adult siblings had distinct retinal changes including the macula. Bone spicules were not a feature. Residual colour vision was present in all patients with measurabl e VA. Rod ERGs were absent at any age; cone ERGs were detectable in early childh ood. To date, VA data have been reported in 51 patients, visual fields in 29 pat ients, and a detailed fundus description in 34 patients. For all three parameters, data were compara ble to the results in our patient cohort. Conclusion: In childhood, patients wit h RPE65 mutations have better visual functions than typically seen in Leber cong enital amaurosis. The phenotype shows a common progressive pattern with intrafam ilial and interfamilial variation. The data suggest a preserved retinal morpholo gy at young ages, arguing for vision-restoring gene therapy trials in childhood . Purpose: To quantify retinal function longitudinally and crosssectionally in p atients with autosomal-recessive early-onset severe retinal dystrophy (EOSRD) associated with RPE 65 mutations. Subjects and methods: The ocular phenotype was characterized in four children from three families up to the second decade of li fe, and in three siblings from one family aged 43-54 carrying compound he terozygous or homozygous mutations in RPE65. Standard clinical examination inclu ded color vision testing, fundus photography and Goldmann visual fields (GVF). Full-field ERGs ( in all) and multifocal ERGs (in both patients) were also recorded ed. Visual Effects and fundus appearance were compared to literature data. Résults: In childhood, visual acuity (VA) ranged from 0.1 to 0.3, and GVF for tar get V4 was well preserved. VA and GVF were measurable in only one of the three a dult siblings. Nystagmus was present in two of four children and two of three ad ults. Photophobia was absent in child hood and developed in adulthood. Funduscopi c changes were discrete during the first decade of life in three of four childre n; one patient had clear macular changes already at age 5 years. All three adult siblings had distinct retinal changes including the macula. Bone spicules were not a feature. Residual color was was in all patients with measurabl e VA. Rod ERGs were absent at any age; cone ERGs were detectable in early childh ood. To date, VA data have been reported in 51 patients, visual fields in 29 pat ients, and a detailed fundus description in 34 patients. For all three parameters, data were compara ble to the results in our patient cohort. Conclusion: In childhood, patients wit h RPE65 mutations have better visual functions than typically seen in Leber cong enolysis. The phenotype shows a common progressive pattern with intrafam ilial and interfamilial variation. The data suggest a preserved retinal morpholo gy at young ages, arguing for vision-restoringgene therapy trials in childhood.