To the Editor.
—Bressler et al1 raise the interesting question as to whether visual function can be maintained if pigment epithelium is lacking. The authors present two cases in which a large pigment epithelium rip underlying the fovea did not reduce central visual acuity to worse than 20/40 and 20/32.The authors seem to favor the speculation that "macular RPE [retinal pigment epithelium] may not be essential for maintenance of central vision." They do also mention that "foveal photoreceptors may be apposed to RPE that was not visible biomicroscopically or angiographically."We have performed experimental work that would favor the latter explanation.2 When the retina and pigment epithelium are removed experimentally, a profuse leakage of fluorescein occurs through bare Bruch's membrane into the vitreous cavity. This leakage terminates quickly because of a thin layer of unpigmented cells covering the defect. Such profuse leakage has been observed in human
Machemer R, Heriot W. Retinal Pigment Epithelial Tears Through the Fovea With Preservation of Good Visual Acuity. Arch Ophthalmol. 1991;109(11):1492-1493. doi:10.1001/archopht.1991.01080110026009