Glaucoma

Consultants:

-Ms Poorna Abeysiri

Secretary: ???- T: 01708 503278 | ext ??: email

Urgent advice line: 01708435000 Ext. 6662

Emergency referrals/referral e-mail address: Please fill in the Urgent eye emergency referral form and email to bhrut.urgenteyecare@nhs.net

Glaucoma related conditions and appropriate referral pathway

  1. Primary open angle glaucoma
  2. Acute angle closure glaucoma
  3. Normal tension glaucoma
  4. Bleb related infection
  5. Pseudoexfoliation
  6. Pigment dispersion syndrome
  7. Neovascular glaucoma

Patients should be referred if the optometrist identifies one or more of the following:

  • Optic disc signs consistent with glaucoma in either eye.
  • IOP in either eye exceeds 22 mmHg (note referral in specific scenarios below).
  • A visual field defect consistent with glaucoma is detected in either eye.
  • A narrow anterior drainage angle on van Herrick testing consistent with significant risk of acute angle closure within the foreseeable future (refs 3,4).
  • Signs often associated with glaucoma (e.g. pigment dispersion or pseudoexfoliation).

Primary open angle glaucoma

Primary open angle glaucoma is a relatively common eye condition where the intraocular pressure (IOP) in the anterior chamber of the eye (see Figure 2) is chronically raised. Over time this chronic increase in pressure causes irreversible damage to the optic nerve at the back of the eye and leads to ‘cupping’ and pallor of the optic nerve and progressive peripheral visual fields loss.

Typically there are no symptoms or visual disturbance noticed by the patient and the condition is picked up during routine examination at the optician. A normal IOP is between 8-22. Risk factors include age >60 years, a positive family history in a first degree relative, myopia (short sightedness >3D), being black, asian or hispanic, having conditions such as hypertension, diabetes or sickle cell anaemia or having thin corneas.

Refer patients routinely or ‘soon’ to the ophthalmology department for a review within the next 4 months.

*Patients with bilateral disc haemorhages, an IOP 30-34 or with intermittent angle closure symptoms should be referred for a review in 2-4 weeks.*

(Typically if patients are seen in primary care with an intraocular pressure <35mmHg they are not started on intraocular pressure lowering medication until they have been assessed by the glaucoma team. They should be referred to the ophthalmology glaucoma department for a review in the next 2 weeks.)

Acute angle closure glaucoma

This is an ophthalmic emergency and the possibility of blindness should not be underestimated. This condition occurs when the intraocular pressure (IOP) in the anterior chamber increases often due to obstruction of outflow of aqueous humour through the trabecular meshwork. The normal eye pressure is between 12-22 mmHg. Despite a rise in IOP the patient may not become symptomatic until the pressure rises above 50mmHg.

Symptoms include severe eye pain, nausea and vomiting and a reduction in vision often due to corneal oedema. Signs may include a fixed, dilated pupil and an injected eye. Manual palpation of the patients globe with their eye closed compared to your own eye may feel firmer. Symptoms often start in dim lighting ie. in the evening.

If you suspect acute angle closure glaucoma, offer analgesia and antiemetics and lie the patient supine.

Refer urgently to the Emergency Eye clinic by calling the urgent advice line: 01708 435 000 Ext. 6662.

If out of hours then advise may be sought from Moorfields Eye hospital Main switchboard number 020 7253 3411 and ask to speak to the A+E staff or Moorfields Direct A&E: 020 7521 4682.

Please do not send patients without prior discussion. Patients will not be triaged and may be turned away.

Fill in the the Urgent eye emergency referral form and email it to bhrut.urgenteyecare@nhs.net for an ophthalmology review which we will follow up.

Normal tension glaucoma/ Ocular hypertension

Normal tension glaucoma

Normal tension glaucoma occurs when the intraocular pressure is within normal range 12-22 mmHg however there are signs of visual field loss or damage to the optic nerve. Refer routinely to the glaucoma ophthalmology department for a review within the next 18 weeks.

Ocular hypertension

Ocular hypertension occurs when the IOP is above normal range (22mmHg), without any anterior segment abnormality, visual field loss or optic nerve cupping. 10% of ocular hypertensives will develop glaucoma over the next 5 years.

Refer routinely to the glaucoma service for a review in the next 18 weeks.

Bleb related infection

Surgical management of glaucoma sometimes includes an operation called a trabeculectomy where a new channel or ‘bleb’ is created from the anterior chamber to under the conjunctiva to help drain the aqueous fluid from the anterior chamber of the eye. The bleb is often created on the superior, lateral aspect of the globe, above the corneal limbus under the upper eye lid.

If the bleb becomes infected it is a potentially blinding condition as pathogens may enter the eye and cause an endophthalmitis. The onset of infection from time of the trabeculectomy operation varies from months to years. It is a different pathogenesis of acute post surgical endophthalmitis where the infective organism is thought to be introduced at the time of surgery. This is also an important condition to recognise and treat.

Risk factors include a thin walled, cystic bleb, an inferiorly located bleb, chronic bleb leak, bacterial conjunctivitis, prior history of bleb infection, ocular surface disease, nasolacrimal duct obstruction, contact lens use, upper respiratory tract infection, ocular trauma, myopia and immunosuppression due to e.g. diabetes, malignancy, systemic steroid use.

Clinical features include redness, pain, photophobia, purulent discharge and signs may include mucopurulent infiltrate in the bleb, conjunctival injection, AC activity, hypotony  and possible vitritis.

If suspicious refer urgently to the Emergency Eye clinic by calling the urgent advice line: 01708435000 Ext. 6662.

If out of hours then send of a conjunctival swab for micro, cultures and sensitivities and start the patient on hourly Moxifloxacin day and night and advise in the Urgent eye emergency referral form and email it to bhrut.urgenteyecare@nhs.net for an ophthalmology review which we will organise for the next day.

(Moxifloxacin is contraindicated in children and patients with liver disease. Please use ciprofloxacin 750mg PO BD for 10 days instead).

Pseudoexfoliation

This is a systemic, age related condition where protein rich, fibrillar deposits are formed and coat the anterior structures in the eye including the lens capsule, lens, iris, ciliary epithelium, corneal endothelium and trabecular meshwork. The flaky material can block the trabecular meshwork and cause a secondary glaucoma in around 30% of patients who have it. It may make cataract surgery slightly more challenging and increase the rate of intra-operative complications.

Risk factors include age over 50 years, being of Scandinavian race, female gender and high UV light exposure.

On examination at the slit lamp, flaky material is seen around the border of the iris on the anterior lens capsule.

Please refer routinely (within 18 weeks) to the glaucoma ophthalmology department unless there are signs of optic nerve dysfunction or an IOP >22 then refer for a review within a month.

Pigment dispersion syndrome

This is a condition where pigmented cells in the back of the iris rub off against the fibres supporting the front of the lens. These pigmented cells may float to and clog up the trabecular meshwork draining channels which may lead to an increased intraocular pressure as aqueous drainage is decreased. It may progress to a a form of secondary glaucoma in 10-15% of cases.

Signs on examination include a pigmented trabecular meshwork on gonioscopy (Sampaolesi line), pigmented cells seen stuck to the back of the corneal endothelium (Krukenberg’s spindle) and iris transillumination defects.

The disease is more prevalent in males, typically presents in the 3rd-4th decade of life and is more common in myopes.

Please refer routinely (within 18 weeks) to the glaucoma ophthalmology department unless there are signs of optic nerve dysfunction or an IOP >22 then refer for a review within a month.

Neovascular glaucoma/ iris rubeosis

This is a severe form of glaucoma that forms following the proliferation of fibrovascular vessels in the anterior chamber angle which may block the aqueous outflow. It is usually  due to retinal ischaemia (e.g due to central retinal vein occlusion or proliferative diabetic retinaopathy.) This should be referred to the ophthalmology department for a review within the next 2-4 weeks.

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