- This is a multi-systemic condition whereby fibrillary material is deposited in various regions of the body. For example, if it deposits in the conduction pathway of the heart, patients can be prone to dysrhythmias
- Seen most commonly in Scandanavians, although apparent in all racial groups. Very common in Oxford!
- Unfortunately, the presentation of disease is later than in patients with primary open angle glaucoma: with advanced field loss and difficult cataract surgery, these patients are exquisitely difficult to manage….
- The fibrillary material can deposit in the TM leading to an obstruction of outflow. Hence the risk of glaucomatous optic neuropathy at 15 years is 15-30%
- SLT is an excellent surgical option in early disease, as the pigment can uptake the laser. The same rationale applies for patients with pigment dispersion syndrome: SLT is an excellent option. Be careful and only do 180 degrees unilaterally in these patients, as a pigment spike may cause very high pressure spike….
- It crosses the blood brain barrier: do not administrate to young children or breast feeding mother’s
- Some studies show that it works in a dual mechanism:
- Reducing aqueous humour at the level of the ciliary processes
- Increasing uveoscleral outflow, similar to PGA
- Be extremely cautious using in patients on anti-depressants, with particular emphasis on:
- Tricyclic antidepressants cause brimonidine to be less efficacious
- Monoamine oxidase inhibitors, concurrent use can precipitate a hypertensive crisis
Whilst glaucoma can present with any type of visual field defects, the most common early defect is a paracentral scotoma.
- Some gonio-lenses have a small diameter, hence are ideal for indentation. Applying pressure on the eye can forcefully deepen the ‘angle’. This can distinguish between appositional and synechiael angle closure.
- This can also be achieved by changing from a dim light to a bright one, without using an indenting goniolens: if there is no constriction segmentally, this would indicate synechaiel closure.
Retinal surgery and glaucoma
- Acute rhegmetogenous RD can lead to photoreceptors migrating into the AC, blocking the TM and causing raised intraocular tension. This is called Schwartz-Matsuo syndrome.
- This family of hypotensive agents work to lower the pressure by increasing uveo-scleral flow
- The exception to this is bimatoprost, which also increases flow through the trabecular meshwork
- Should not be routinely stopped in patients post-phaco: very minimal evidence that it helps to avoid Irvine Gass syndrome. However, possibly avoid in uveitis due to risk of CMO
- Cause a theoretical risk of spontaneous abortion
Carbonic Anhydrase Inhibitors
- Very occasionally, these can cause corneal decompensation in patients with precarious endothelial dysfunction: be wary in patients with conditions such as Fuch’s ED
- CAI can also lead to recurrence of Herpetic simplex virus….
- Trusopt and azopt can cause bitter taste, as can oral carbonic anhydrase inhibitors
- I use MMC for each trab surgery I perform, the rationale being it entwines with DNA chains of fibroblasts and prevents their proliferation.
- The risk of using MMC (particularly in elderly patients) is producing thin, avascular blebs, which have higher risks of leaks and BRI/BRE.
- In this collection of conditions (collectively termed ICE), the endothelial cells take the characteristics of epithelial cells. Hence corneal decompensation occurs (mostly in Chandler’s syndrome) necessitating grafting
- These patients do poorly with topical therapy: most frequently they need tube surgery as definitive treatment
- An aphakic eye with silicone oil will get pupil block: the SO will provide a physical barricade to flow overlying the pupil.
- TO prevent pupil block an iridectomy is vital: however if done superiorly, the SO will block it and the pupil block will not be alleviated
- Hence do an inferior one: eponymous names is: ‘Anton’s iridectomy’
- I use this for patients with very small anterior chamber under-going lens extraction to afford greater space in the surgical field. It works by creating an osmotic gradient between the blood and the vitreous: this draws out fluid from the vitreous, enabling less positive vitreous pressure and greater space in the anterior chamber.
- Possibly overly diagnosed in UK casualty, not as common as diagnosis given
- Angle must be open, no PAS, minimal AC cells, very high IOP’s from a trabeculitis