Figure 1. Can any of the features in this slit lamp exam help you identify if this is the patient described in the case?
Figure 2. Can any of the features in this slit lamp exam help you identify if this is the patient described in the case?
Figure 3. Can any of the features in this slit lamp exam help you identify if this is the patient described in the case?
A 64-year-old woman presented to the clinic with complaints of reading problems. Her bifocals were +1.25 -.50 x 80 20/20- OD, and +1.50 -.50 x 85 20/20 OS add +2.00 OU. A slit lamp exam revealed very early lens changes in the right eye, more so than the left. No corneal edema was noted. A shallow anterior chamber was noted peripherally. With gonioscopy, no structures were seen through the circumference in either eye. Her right pupil was slightly larger than the left and reacted sluggishly to light. The IOP was 50 mm Hg OD and 16 mm Hg OS. She had no eye pain, no corneal edema, and no conjunctival injection. The cup-to-disc ratios were 0.7 OD and 0.4 OS. Photos were taken of her pupils and angles with both a slit lamp and 3 mirror gonioscope. She was diagnosed with angle closure glaucoma in the right eye. A glaucoma specialist was contacted, and the patient was scheduled for an emergency visit the next morning. The glaucoma specialist noted IOPs of 36 mm Hg OD and 14 mm Hg OS. Her cup-to-disc ratio remained the same. The specialist diagnosed her with subacute angle closure glaucoma in the right eye. The patient was started on pilocarpine 1% and timolol 0.5% for the right eye. Thirty minutes after drops, the right pupil was smaller and IOP was 29 mm Hg. The patient was scheduled for YAG iridotomy in the right eye within 1 to 2 days.
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In the photos, follow the slit beam between the iris and lens. In Figure 1, no space exists in the slit beam where it meets the iris and lens. Look carefully at both top and bottom locations, as the lens is blocking the flow of aqueous (relative pupillary block). This is the photo that matches the patient described in the case. In all the other photos, the slit beam is not continuous.
Relative pupillary block in the presence of an anatomically narrow angle may result in angle closure glaucoma. Also, with a narrow angle, if the pupil is dilated with diagnostic drops or naturally in the dark, angle closure glaucoma may occur. If the attack is sudden (acute), it is painful; but, if the attack is gradual, and the relative pupillary block resolves on its own without synechiae, as in this case, it is termed “subacute.” Gradual increases in eye pressure are often not painful. This case serves to remind clinicians when they see patients without many of the classical symptoms of angle closure that they need to rule it out, by performing careful gonioscopy. As a prophylactic measure, the patient was scheduled for YAG iridotomy in the left eye at a later date.
This case had no pain, no eye redness, and no corneal edema. Subacute angle closure is not rare. Keep in mind that the mid dilated pupil position, as in her case, contributed to the relative pupillary block. The other photos are presented to show no relative pupillary block, but they are not in the mid dilated position.
This reaffirms the concept that a careful evaluation of the angle anatomy and closure potential is always important in patients with shallow peripheral anterior chambers.
Nesher R, Mimouni M, Khoury S, Nesher G, Segal O. Delayed diagnosis of subacute angle closure glaucoma in patients presenting with headaches. Acta Neurol Belg. 2014;114(4):269-72. doi:10.1007/s13760-014-0290-2
Matthew Garston, OD, is an adjunct professor at the New England College of Optometry and was a senior staff optometrist in the medical department at MIT for 43 years.