Glaucoma Mega Brief Version

Progressive optic neuropathy associated with elevated IOP. Has characteristic field defects - nasal step, arc scotoma etc. Lowering IOP is protective even in normal tension glau.

Fluid in the eye is produced and drained away at a certain rate. Glaucoma doesn't involve a problem with increased production, it's a drainage issue. You can help by lowering the production though. Normal IOP is considered to be 21 or less. Ocular hypertension is when pressure is higher than normal but the px doesn't have glaucoma. There's a diurnal fluctuation - usually higher in the AM.

Goldmann/Perkins is used if optom is unsure whether to refer or not. History can give clues - hyperopes are more prone to closed angle glaucoma whereas myopes are more prone to open angle. If the patient has had refractive surgery then the change in rigidity/flatness of the cornea could lead to underestimation of the pressure. Also side effects of asthma treatment could increase chance of glau.

Damage may progress as follows - if some nerves are damaged then the surrounding nerves can follow. It's thought that using some drugs the surrounding nerves can be spared. Research into this is in progress the noo.

The optic disc is imaged mostly with the direct ophthalmoscope but indirect biomicroscopy is becoming more widespread in practice. Also fundus photography, stereo imaging and computerised topography. Disc assessment concerns the cup and disc size. The disc should follow the ISNT rule, if it doesn't then suspect glaucoma. The NRR should be thickest at the inferior, then superior, then nasal, then temporal. Also look for focal loss of ON fibre tissue and disc haemorrhages.

Assessment of the anterior chamber angle can be with Van H's on the slit lamp, ultrasound, Gonioscopy - shaffer grades.

There are various types of glaucoma - open and closed/narrow angle, chronic and acute, primary and secondary, congenital, juvenile and adult.

With pseudoexfoliative glaucoma small flecks of white material are noticed in the pupil (on the edge of the lens). They are very easily seen if the pupil is dilated. Other types include pigmentary, uveitic, steroid induced and rubeotic.

Angle Closure glaucoma assessment. As I typed before closure is more likely in a hypermetropic patient. Ask if any headaches/intermittent blurred vision, haloes around lights (corneal oedema), whether taking anti-deps, drugs for asthma etc. If px has IOP of 60 or something could do gonioscopy, instil pilo, acetazolamide, peripheral iridotomy, surgery (trabeculectomy/lens extraction)

Angle closure typically involves small eyes, a mid-dilated fixed pupil, iris atrophy, ON cupping/field loss

Normal Tension Glaucoma - 10-30% of glaucomas are actually normal IOP. This is mostly older PX. If you can lower pressure more still by using medication or surgery then you can slow down progression.

Pilocarpine causes constriction of ciliary muscle fibres, opens trabecular meshwork, increases outflow, causes miosis, headache and low vision in dim light, also contributes to myopia, cataract and accommodative spasm. Instilled 4x/day

Adrenergic type drugs like epinephrine increase aqueous drainage. They can cause adrenochrome deposits (black granules in conj), mydriasis (angle closure glau), rebound hyperaemia and allergic reaction

Alpha-2 agonists like apraclonidine are not often used. They decrease production and increase drainage but cause dry mouth, allergy, headache and fatigue.

Beta Blockers - beta receps in eye moderate aq production so blockers decrease secretion. They become less effective over time and can cause bronchospasm which in asthma px could actually cause respiratory failure and even death if given enough drops. Preps inculde timolol, betaxolol

Prostaglandins increase outflow via trabecular and uveoscleral routes. eg latanoprost. 50% of px are on this. Can cause increased iris pigmentation, thicker eyelashes and hyperaemia. It's expensive too.

Carbonic Anhydrase Inhibitors like acetazolamide are used in the short term for px w/uveitis. Side effects include nausea, lethargy, metallic taste, kidney stones, all. reaction. Combos of the above are also used.

Surgery could involve iridotomy, iridectomy, laser trabeculoplasty. Probs include plain old failure of it to work, accelerated cataract, endophthalmitis