Mushtaq Ahmad Baig, Amjad Akram, Mazhar Ishaq, Naseer Raja.
Normal Tension Glaucoma errors in diagnosis.
Pak J Ophthalmol Jan ;18(1):23-5.

Normal Tension Glaucoma/(NTG) is a condition, which can be mimicked by a variety of conditions. Three actual case examples are discussed where misdiagnosis of NTG was made even though the patients had different underlying pathologies. Measures are also suggested which should reduce the pitfalls, when diagnosing NTG.lesions.

Case Report 1: A 30 years old man who was being treated as having normal tension glaucoma for the past many months presented at our eye dept with the complaint that his vision was getting worse with the passage of time. His visual acuity was hand movement in right eye and 6/60 in the left eye with no further improvement. He had `normal` intraocular pressure of 18mmHg in each eye and was on a topical beta-blocker for the past many months. Fundus examination showed marked cupping of the optic discs with advanced optic atrophy in both eyes. He had markedly constricted visual fields. One of our colleagues ordered a plain X-ray of the skull since the CT scan was out of order at that time. The X-ray report disclosed `Ballooning of the pituitary fossa most likely due to a pituitary tumour`. The patient was referred to the neurosurgeon who removed the tumour, which turned out to be a pituitary adenoma.

Case Report 2: A middle-aged man was being treated for uniocular NTG in the left eye for many years. On examination his visual acuity was 6/6 unaided in the right eye and perception of light in left eye. Intraocular pressure was 12mmHg in the right and 14mmHg in the left eye. The visual fields in the left eye could not be performed owing to the inability of the patient to see the fixating target. Field of the right. Eye was completely normal. As part of our strategy to reevaluate all the cases who were being treated as normal tension glaucoma, it was decided to get an MRI of brain and visual pathways. Increasingly interesting was the fact that this patient was said to have the disease in the left eye only whereas usually normal tension glaucoma tends to occur in both eyes most of the time. The MRI scan read the following report, ` `Aneurysm of the anterior cerebral artery compressing on the left optic nerve`.

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