Normal-tension glaucoma

An initial target intraocular pressure should be set at 20% lower than the patient s baseline intraocular pressure. The target intraocular pressure can be set lower (30% to 50% of baseline intraocular pressure) for patients that already have severe disease or have normal-tension glaucoma. 

Currently, glaucoma therapy remains focused on mechanisms designed to decrease intraocular pressure (IOP) and this approach is considered effective also in normal tension glaucoma. 

The diagnosis of open-angle glaucoma is confirmed by the presence of characteristic optic disk changes and visual field loss, with or without increased lOP. Normal tension glaucoma refers to disk changes, visual field loss, and lOP of less than 21 mm Hg. Ocular hypertension refers to lOP of more than 21 mm Hg without disk changes or visual field loss. 

Ang A, Reddy MA, Shepstone L, et al. Long term effect of latanoprost on intraocular pressure in normal tension glaucoma. Br J Ophthalmol 2004 88 630-634. 

Both syndromes are thought to be associated with obstructive sleep apnea (OSA) and normal tension glaucoma however, this correlation remains questionable. 

Collaborative Normal-Tension Glaucoma Study (CNTGS)... 

ALT = argon laser trabeculoplasty NTG = normal tension glaucoma ONH = optic nerve head PXG = pseudoexfoUative glaucoma. 

Tafluprost significantly increases retinal blood flow and blood velocity in animal models. The improvement of ocular blood flow is thought to be relevant in glaucoma therapy, especially for normal-tension glaucoma patients since it is assumed that optic nerve damage is involved not only in mechanical compression caused by IOPbut also in impairment of ocular blood flow. 

Collaborative Normal-Tension Glaucoma Study Group, (1998) Comparison of glaucomatous progression between untreated patients with normal-tension glaucoma and patients with therapeutically reduced intraocular pressures. American Journal of Ophthalmology. 126, 487 197. 

CaprioU J. The treatment of normal-tension glaucoma. Am J Ophthalmol 1998 126 578-581. 

Kamal D, Hitchings R. Normal-tension glaucoma A practical approach. Br J Ophthalmol 1998 82 835-840. 

Tomita G. The optic nerve head in normal-tension glaucoma. Curr Opin Ophthalmol 2000 11 116-120. 

Skin A patient with unilateral normal-tension glaucoma and another with unilateral primary open-angle glaucoma, both of whom used travoprost monotherapy unilaterally for 2 years, gradually developed deepening of the eyelid superior sulcus, with hyperpigmentation in the eyelid skin of the treated eye [44" ]. The disparity between the treated eye and the fellow eye was clearly visible and resolved after... 

Sensory systems Eyes In a trial to evaluate the efficacy and safety of bimatoprost ophthalmic solution 0.03% in normal-tension glaucoma patients, the scores for conjunctival hyperaemia in the treated eyes were increased at each... 

Leopold and Comroe2 studied the use of 0 05, 01 and 0-2 per cent D.F.P. in arachis oil in glaucoma, and found that cases unrelieved by eserine responded readily to 01 per cent D.F.P. instilled into the conjunctival sac. However, the action of D.F.P. in the glaucomatous eye lasts for about 12 hr. compared to an action of about 12 days in the normal eye. The short-lived action of D.F.P. in cases of raised intra-ocular tension lends evidence to the suggestion that there may be an upset of the acetylcholine-cholinesterase mechanism in glaucoma. There are certain side effects such as ciliary spasm and headache which may prove troublesome during treatment. 

Cursiefen C, Wisse M, Cursiefen S, Junemann A, Martus P, Korth M (2000) Migraine and tension headache in high-pressure and normal-pressure glaucoma. Am J Ophthalmol 129 102-104. 

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