For a glaucomatous eye that has already suffered some form of peripheral visual loss, does the vision improve after the treatment of glaucoma (keeping the definition of glaucoma and the associated treatment general) or does the treatment merely prevent the eye (optic nerve) from further damage?
The treatment merely prevent the eye (optic nerve) from further damage, but some kind of neuroprotective therapy can enlarge a little VF,depending on ganglion cell loss, if started at earlier stages
Visual field defects in adults are usually irreversible ,treatment is to prevent further damage. But in children reversal of optic nerve cupping can be seen post treatment especially in early stages along with improvement in visual fields .
Same ad above, moreover you have to consider the patient learning curve and the Inter-exam fluctuation, the real vf may be better than looks at the frist/second exam so at third exam, usual in therapy, the vf could look improved.
It is interesting that some studies show some short-term visual field improvement after treatment (e.g trabeculectomy). Below are some references. These findings could imply that the retinal ganglion cell may have some form of reversibility which had also been seen in studies utilizing other psychophysical tests (ERG, contrast sensitivity, color vision, etc). It is indeed interesting despite the fact that we know this disease to be irreversible.
1) Bhandari A, Crabb DP, Poinoosawmy D, Fitzke FW, Hitchings RA, Noureddin BN. Effect of surgery on visual field progression in normal-tension glaucoma. Ophthalmology. 1997;104(7):1131–1137.
2) Pederson JE, Herschler J. REversal of glaucomatous cupping in adults. Arch Ophthalmol. 1982;100(3):426–431. doi:10.1001/archopht.1982.01030030428008.
3) Salim S, Paranhos Jr A, Lima M, Shields MB. Influence of surgical reduction of intraocular pressure on regions of the visual field with different levels of sensitivity. Am J Ophthalmol. 2001;132(4):496–500. doi:10.1016/S0002-9394(01)01188-6.
4) Vuori M-L, Vainio-Jylhä E, Viitanen TT. Localised changes in glaucomatous visual fields after trabeculectomy. Acta Ophthalmol Scand. 2001;79(5):468–471. doi:10.1034/j.1600-0420.2001.790507.x.
5) Gandolfi SA. Improvement of visual field indices after surgical reduction of intraocular pressure. Ophthalmic Surg. 1995;26(2):121–126.
6) Yildirim E, Bilge AH, Ilker S. Improvement of visual field following trabeculectomy for open angle glaucoma. Eye. 1990;4(1):103–106. doi:10.1038/eye.1990.12.
7) Holmin C, Storr-Paulsen A. The visual field after trabeculectomy. A follow-up study using computerized perimetry. Acta Ophthalmol (Copenh). 1984;62(2):230–234.
8) Greve EL, Dake CL, Verduin WM. Pre- and post-operative results of static perimetry in patients with glaucoma simplex. Doc Ophthalmol. 1977;42(2):335–351. doi:10.1007/BF02742247.
Thanks John Mark de Leon for the collection of references as in my clinical practice also noticed that in some cases we do get improvement in visual function after control of intra ocular pressure.
You are welcome.
In fact Dr George Spaeth (see attachment) long ago in 1985 presented the possibility of establishing new criteria for judging benefit of reduced IOP in glaucoma in terms of an improved rather than stable visual function.
Mystery of glaucoma lies in comparing the histology of the non-glaucomatous disc with glaucomatous disc. In former the nerve fibers are still present though shrunken and disorganized whereas in glaucomatous disc there are no nerve fibers, no lamina, no physiological cup, not even the vasculature except some larger vessels still hanging on the rim. It does not appear to a 100% cupped disc as widely believed over 150 years but a crater left over after the severance of nerve fibers and its vasculature. If my hypothesis that severance of the nerve fibers and excavation of the disc are unique features of glaucoma then there is no way the visual fields can be improved as the cut nerve fibers can never be reunited again. My hypothesis of severance of nerve fibers has been confirmed by a recent article published from Saudi arabia. page 1947 Ref;32
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3792954/
https://www.facebook.com/pages/Glaucoma-Paradigm-Shift-Project/516804278413418
Latest observations and studies are showing improvement of visual field in glaucoma patients. Earlier we ophthamologists would consider visual field changes as irreversible. However recently I have come across a few articles which do show some improvement with adequate control of IOP and other factors.
the early you lower the IOP is the safer for protection nerve fibers, the more IOP reduction is the best with the visual field changes
Visual fields tests are purely subjective and unreliable giving us different country maps each time. Subjective cooperation is variable each time due to one's energy level and concentration at the time of test. We hand over the clicker to a 80 year old patient and walk away and expect a error free visual fields results!
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