Definition

Closed or Narrow angle glaucoma (NAG) is a very different manifestation of the disease. In acute NAG (or ANAG), the patient can lose permanent vision very rapidly and can go completely blind in hours or days. This is one of the few true ocular emergencies in eye care. In chronic NAG, the patient slowly loses optic nerve tissue due to the anatomy of the patient causing a mechanical cause of decreased outflow of intraocular fluid. These glaucoma sub-varieties are very serious and typically fast in their progression.

Work-up

Work-up for ANAG patients includes careful history, especially of eye pain (could be sub-acute attacks), headaches, feelings of pressure and redness of the eye. This is in contrast to OAG as these are not typical symptoms of that disease. Pupils also take on a more important role and measurement of angle openness. Any question of the angle should be brought to the doctor’s attention immediately and the patient should not be dilated, especially if a laser peripheral iridotomy has not been done in the eyes.

Testing

CNAG testing is no different than other glaucoma patients, except that the depth and appearance of the anterior chamber (front of the eye) becomes much more important in the evaluation and management of the case. Due to this, gonioscopy is done more often at the doctor’s discretion.

Gonioscopy will be needed typically on the first visit or soon thereafter to look at the place in the eye where fluid drains out of the eye. In narrow angle glaucoma this test is critical in the diagnosis and management of the disease as the angle here is closed does not let fluid out of the eye, resulting in a dangerous spike in intraocular eye pressure.

Optic nerve photography is also very important as it gives the doctor photographic evidence of what the patient’s optic nerve looked like at that moment in time. Much like following skin lesions for suspicion of cancer, photographs are critically important in looking for change over time.

HRT or Optical Coherence Tomorography (OCT) are the modern technologies that Newsom Eye uses to laser scan the nerve fiber layer of the optic nerve and not just analyze it against a normalative database for disease, but to also store that for future reference with the patient to detect even the slightest progression of the disease.

Pachymetry is used to measure the central corneal thickness which we now know is an important data point to reference for glaucoma risk. This test is usually only performed once, unless surgery or trauma changes the structure of the cornea. Occasionally, due to swelling in an acute attack, this test will be repeated after the patient has recovered from the attack and the pressure and cornea have normalized.

Treatment

CNAG glaucoma is treated much differently than OAG. Laser peripheral iridotomy takes primary role here, with other treatments sometimes being needed in mixed mechanism cases.  Sometimes treatment is an ocular emergency, which is why having the necessary equipment on site for Newsom Eye’s physicians to utilize at the time of a crisis is critically important to not having a delay in treatment.

 

Gonioscopy:This is an important test where a mirrored, handheld device is used by the doctor to look at the drainage channel in the patient’s eye. 3 mirror gonioscopy lens and a view inside the eye
Visual Field: This is required to analyze and document the peripheral vision of the patient.  Peripheral vision is what glaucoma damages over time. Humphrey Visual Field
Photos of the Optic Nerve: Glaucoma damages the optic nerve, therefore pictures are taken to watch for changes in this important tissue. Digital Retina Camera
Optical Coherence Tomography (OCT): Perhaps the most important and technologically advanced instrument available for glaucoma, this instrument provides an optical analysis of the nerve with stunning accuracy. Zeiss OCT instrument and scan
Serial Tonometry: Intraocular pressure, or the pressure in the eye, varies throughout the day and is a critical measurement in glaucoma.  Multiple pressure measurements are necessary to record the variation and help understand this condition. Pressure test
Pachymetry: This is a newer test that standardizes the pressure reading for patients by measuring the thickness of their cornea. Corneal Pachymetry