It is well known that visual acuity may remain normal in cases of tabetic optic atrophy for several months after the appearance of pallor of the disk. In fact, the pallor practically always precedes the diminution of central vision. It is not definitely known whether this is also true for the boundaries of the peripheral visual field, since contraction of the field is nearly always found when the pallor of the disk is first detected.
The appearance of pallor before loss of central vision has been used as an argument to prove that tabetic optic atrophy must be an ascending, and not a descending, degeneration, for in descending degeneration the central vision is always affected before the atrophy becomes evident as a pallor of the optic disk. A good example of this is the blindness which follows fracture of the orbit involving the optic foramen. In these cases the
ADLER FH. APPARENT OPTIC ATROPHY WITH RECOVERY OF NORMAL CENTRAL VISUAL ACUITY. Arch Ophthalmol. 1934;11(6):942–946. doi:10.1001/archopht.1934.00830130024002