Effect of retinopathy of prematurity on scotopic spatial summation.
OBJECTIVE
To evaluate scotopic retinal organization in retinopathy of prematurity (ROP) through a study of spatial summation.


METHODS
Thresholds for a range of stimulus diameters (0.4°-10°) were measured using a two alternative, spatial, forced choice psychophysical procedure. The critical diameter (DCRIT) for complete summation was estimated in subjects with a history of severe ROP (N = 7) and mild ROP (N = 17). Subjects who were born preterm and never had ROP (N = 16) and term-born subjects (N = 7) were also tested. The subjects ranged in age from 9 to 17 (median 13.5) years.


RESULTS
Critical diameter for complete spatial summation was significantly larger in ROP subjects than in subjects who never had ROP and in term-born control subjects. Critical diameter varied significantly with severity of ROP.


CONCLUSIONS
The larger DCRIT values in ROP are consistent with altered organization of the post receptor retina. This may offer the ROP retina a strategy for achieving noise reduction and good dark-adapted visual sensitivity.
Department of Ophthalmology, Boston Children's Hospital and Harvard Medical School, Boston, Massachusetts, United States.
Ronald M
RM
Hansen
Department of Ophthalmology, Boston Children's Hospital and Harvard Medical School, Boston, Massachusetts, United States.
Jena L
JL
Tavormina
Department of Ophthalmology, Boston Children's Hospital and Harvard Medical School, Boston, Massachusetts, United States.
Anne
A
Moskowitz
Department of Ophthalmology, Boston Children's Hospital and Harvard Medical School, Boston, Massachusetts, United States.
Anne B
AB
Fulton
D000293:Adolescent; D002648:Child; D003623:Dark Adaptation / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D010775:Photic Stimulation; D011601:Psychophysics; D017948:Retinal Rod Photoreceptor Cells / Q000502:physiology*; D012178:Retinopathy of Prematurity / Q000503:physiopathology*; D012684:Sensory Thresholds; D014796:Visual Perception / Q000502:physiology*
psychophysics; retinopathy of prematurity; scotopic sensitivity; spatial summation