Dual-perspective analysis of vascular formations in sickle cell retinopathy
D. S. McLeod, M. F. Goldberg and G. A. Lutty
Johns Hopkins Applied Physics Laboratory, Laurel, Md.
OBJECTIVE: To examine the sickle cell retina in dual perspective (vascular
patterns en bloc and structure in serial sections) to gain new insights
into sickle cell retinopathy. METHODS: We analyzed the retinas of two
patients with sickle cell disease (a 54-year-old patient with hemoglobin
SC, heterozygous for the S and C mutation in the beta chain of the globin
gene, and a 20-month-old patient with sickle cell anemia [SS], homozygous
for the S mutation) using the previously described adenosine diphosphatase
flat-embedding technique. RESULTS: The dual-perspective analysis afforded
by our technique revealed that the primary site of occlusions was located
at the precapillary level. An unusual neovascular formation, the hairpin
loop, was observed in both patients' retinas and appeared to result from
recanalization of the wall of an occluded vessel. Many autoinfarcted
pre-retinal neovascular formations were observed in the older SC patient.
Two patent preretinal formations were studied in detail and their evolution
appeared to be influenced by mechanical factors. The vessels appeared to
have been extruded from the retina, perhaps owing to hydrostatic pressure
secondary to downstream occlusions. Small pigmented lesions consisting of
retinal pigment epithelial cells ensheathing channels that resembled
autoinfarcted vessels were found in the eye of the SC patient. CONCLUSIONS:
This study illustrates unusual morphological features of intraretinal and
preretinal neovascularization and of chorioretinal lesions in sickle cell
retinopathy and suggests alternative mechanisms for their formation.
