Coexisting optic nerve head drusen and glaucoma

Abstract

Authors Roh, Noecker, and Schuman1Roh S. Noecker R.J. Schuman J.S. Evaluation of coexisting optic nerve head drusen and glaucoma with optical coherence tomography.Ophthalmology. 1997; 104: 1138-1144Abstract Full Text PDF PubMed Scopus (48) Google Scholar report two cases of coexisting optic nerve head drusen (ONHD) and glaucoma and demonstrated that optical coherence tomography (OCT) can detect nerve fiber layer loss despite a full-appearing optic disc without evidence of cupping. We congratulate the authors for nicely demonstrating nerve fiber loss in these patients where optic nerve head drusen obscure the cup. Our only concern is their conclusion that “OCT may … aid in the management of these patients by detecting nerve fiber layer thinning earlier than would otherwise be possible.”It is important to stress that OCT cannot distinguish nerve fiber layer loss that occurs from glaucoma from that which occurs from optic nerve head drusen. The authors acknowledge that both glaucoma and optic nerve head drusen can result in nerve fiber layer loss. The presence of elevated intraocular pressure does not necessarily mean that the nerve fiber layer loss detected was a result of glaucoma. This is particularly true in the second case they describe in which intraocular pressures were elevated, Humphrey visual fields did not detect any localized defect, yet OCT demonstrated nerve fiber layer thinning greatest in the distribution of the optic nerve head drusen. In this patient, one clearly cannot distinguish nerve fiber layer loss that may be occurring from the elevated pressure from that due to optic nerve head drusen.Since it is not known whether elevated intraocular pressure alters the progression of nerve fiber layer loss from optic nerve head drusen, simply identifying nerve fiber layer loss may not help in the management of the patient. Perhaps it is more accurate to conclude that OCT may be an excellent technique for identifying nerve fiber layer loss, but that the question of whether the nerve head drusen or glaucoma is the source of loss still cannot be answered. Thus, even with OCT, we are still unsure about how to manage the patient with ONHD, nerve fiber layer loss, and increased intraocular pressure. Authors Roh, Noecker, and Schuman1Roh S. Noecker R.J. Schuman J.S. Evaluation of coexisting optic nerve head drusen and glaucoma with optical coherence tomography.Ophthalmology. 1997; 104: 1138-1144Abstract Full Text PDF PubMed Scopus (48) Google Scholar report two cases of coexisting optic nerve head drusen (ONHD) and glaucoma and demonstrated that optical coherence tomography (OCT) can detect nerve fiber layer loss despite a full-appearing optic disc without evidence of cupping. We congratulate the authors for nicely demonstrating nerve fiber loss in these patients where optic nerve head drusen obscure the cup. Our only concern is their conclusion that “OCT may … aid in the management of these patients by detecting nerve fiber layer thinning earlier than would otherwise be possible.” It is important to stress that OCT cannot distinguish nerve fiber layer loss that occurs from glaucoma from that which occurs from optic nerve head drusen. The authors acknowledge that both glaucoma and optic nerve head drusen can result in nerve fiber layer loss. The presence of elevated intraocular pressure does not necessarily mean that the nerve fiber layer loss detected was a result of glaucoma. This is particularly true in the second case they describe in which intraocular pressures were elevated, Humphrey visual fields did not detect any localized defect, yet OCT demonstrated nerve fiber layer thinning greatest in the distribution of the optic nerve head drusen. In this patient, one clearly cannot distinguish nerve fiber layer loss that may be occurring from the elevated pressure from that due to optic nerve head drusen. Since it is not known whether elevated intraocular pressure alters the progression of nerve fiber layer loss from optic nerve head drusen, simply identifying nerve fiber layer loss may not help in the management of the patient. Perhaps it is more accurate to conclude that OCT may be an excellent technique for identifying nerve fiber layer loss, but that the question of whether the nerve head drusen or glaucoma is the source of loss still cannot be answered. Thus, even with OCT, we are still unsure about how to manage the patient with ONHD, nerve fiber layer loss, and increased intraocular pressure. Coexisting optic nerve head drusen and glaucoma: Authors’ replyOphthalmologyVol. 105Issue 5Preview Full-Text PDF