Makindo Medical Notes.com

Related Subjects: |Episcleritis |Scleritis |Assessing a Red eye |Acute Angle Closure Glaucoma |Allergic and Infective Conjunctivitis |Anterior and Posterior Uveitis |Herpes simplex keratitis (HSK)

After bilateral iridotomy most patients will be totally cured and will need no further medication and have no visual loss.

About

• A cause of a red eye needing urgent treatment
• May be triggered by dark lighting conditions
• Very unlikely in those with prior cataract surgery
• Feel how firm the globe feels on palpation

Digital palpation tonometry can be performed. Using both index fingers to ‘ballot’ the eyeball under gently-closed eyelids, it is possible to compare the ‘hardness’ of the eyeball from one eye to the other. If the affected eye has elevated intraocular pressure, then it will feel very hard and firm to palpation (more like a golf ball than a gelatinous ball).

Aetiology

• Elevated intraocular pressure due to blockage of the drainage of aqueous from the anterior chamber
• Anything that dilates pupils can trigger it e.g. night time
• Anticholinergic medications or sympathomimetic medication which dilate the pupil
• Average age at presentation is 60 and prevalence increases thereafter
• Delay in treatment can lead to damage to the optic nerve and vision loss.

Precipitant: having the pupil half-way dilated

• Stress, excitement, anti-cholinergic drugs
• Spending time in a dark place (such as a dimly lit restaurant)
• Medications that dilate the pupil e.g. Atropine like drugs.

Epidemiology

• Seen in 1 of 1000 whites, 1 in 100 Asians, and 2-4 of 100 Eskimos
• Commoner in females because of their shallower anterior chamber

Clinical

• Red painful eye which is tender and feels hard
• Pupil mid-dilated and fixed, hazy and cloudy cornea
• Systemic symptoms - nausea and vomiting can distract
• Shallow peripheral anterior chamber
• Best (pinhole) visual acuity of each eye
• Another eye has angle-closure glaucoma
• Cataract (which may be part of the cause) - rare post cataract
• Injection of the circumcorneal redness

Investigations

• Gonioscopy, examination of anterior chamber angle
• Slit-lamp examination
• Automatic static perimetry
• Tonometry shows pressure usually > 30 mmHg even 60-70 mmHg

Management

• Urgent Ophthalmological consult
• IV Acetazolamide 500 mg to block the production of aqueous humor.
• IV Mannitol 20% 1-2 g/kg can be given to rapidly reduce the volume of aqueous humor.
• Topical Beta-Blocker (Timolol 0.5%) one drop to block the production of aqueous humor.
• Pilocarpine drops to constrict pupil and open up blocked canal
• Anterior chamber paracentesis (as emergency treatment)
• Laser iridectomy should be done in both eyes though not always at same time