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33 Cards in this Set
- Front
- Back
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Mydriasis contraindications
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- iris supported IOLs
- subluxated crystalline lens - very narrow angles - symptoms/Hx of angle closure |
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Acute Angle Closure
Signs & symptoms |
- ocular pain (plus vomiting)
- conjunctival/ciliary injection - corneal oedema - hazy vision - fixed mid-dilated pupil - pupil block/plateau iris - generally occurs within 1hr dilation - can occur when mid-dilated as pupil returns to normal - full symptomology 4-8hrs after instillation |
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Pupil Block
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- lens seals against the iris as angle narrowed with dilation
- due to combination of iris thickening and anterior iris displacement as tip moves towards root - blocks the flow of aqueous humour from posterior to anterior chamber |
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Plateau Iris
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- large or anteriorly positioned ciliary processes push peripheral iris forward
- crowds angle and obstructs aqueous outflow - chamber deep centrally and shallow peripherally - always assess chamber angle peripherally |
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1. Pre-dilation Procedures
2. Narrow angle Px dilation |
1- Informed consent
- IOP and angles assessment on every occasion 2- dilate earlier in day in case emergency care required - only one eye at initial visit - 0.5% tropicamide - |
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Schaffer scale
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0: iris against TM - definite angle closure risk
Slit: angle b/w iris and TM <10deg - sigt risk I: 10 deg - moderate risk II: 20 deg - slight risk III: >2odeg, but <45deg - low risk IV: 45 deg - no risk |
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Post dilation procedures
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IOP
- if not sigt increased 1hr post tropicamide instillation, unlikely to increase - concerning if more than a few mmHg - Px remain until decrease to baseline values VA - Px should remain if sigt reduced Warn against driving Return if vision decreases, eye pain or redness, nausea, vomiting etc |
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Acute angle closure management
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- consider urgent referral to ophthal - surgical iridectomy or laser iridotomy
- IOP < 50mmHg - topical pilocarpine may relieve pupil block - topical anti-glaucoma meds - apraclonidine, timolol - oral or IV acetazolamide & hyperosmotic agents - tropicamide rarely causes complete closure and IOP responds well to Tx |
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Informed Consent
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- drop function
- routine procedure - risk of CAG attack but checks carried out to determine risk - and procedures to deal with - non-dilation = risk of non-detection, more danger - duration of dilation - vision effects - sunglasses and hat advised, |
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Miotics - Mode of action
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- directly acting parasympathomimetics (cholinergics)
- bind Ach receptors on sphinter and ciliary muscles - mimic Ach -- constriction and accom spasm |
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Pilocarpine 1 %
1. time to miosis onset, time to maximal miosis & recovery time 2. accomodative spasm duration |
1- 10mins, within 1/2 hour, gradual over 6hrs
2- up to 2 hrs |
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Pilocarpine Uses (3)
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1- AAC glaucoma emergency treatment
2. COA glaucoma 3. Adie's Pupil Diagnostic Test - damage to postganglionic NOTE - rarely used in clinical practice now, many ocular and systemic SEs |
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Pilocarpine to treat AACG
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1- AAC glaucoma emergency treatment
- 1 drop 2% every 5 min until miosis - >2% contraind - ineffective if IOP >50mmHg - bc ischaemia of sphincter |
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Pilocarpine to treat COAG
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2. COA glaucoma
- dec IOP by CM contraction -> force on scleral spur -> streches TM -> dec outflow resistance - short-term effects and SEs tf superceded |
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Pilocarpine and Adie's Pupil
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3. Adie's Pupil Diagnostic Test
- CG lesion -> damage to postganglionic PNS pathway to eye - cholinergic hypersensitivity in affected eye - 0.1% constricts affected pupil but not normal |
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Pilocarpine and myrdriasis reversal
- Positives and negatives |
POS
- avoids photophobia - speeds accom return if mydriatic has cycloplegic action NEG - competing action not helpful - Inc pupil block danger - prolongs abnormal structure positions - these structural changes may predispose to angle closure even in those with low closure risk - unnecessary for short-acting mydriatics |
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Pilocarpine: Ocular Side Effects (6)
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- accommodative spasm - browache, pseudomyopia
- miosis - dim vision at night - pupil block glaucoma - conjunctival injection - BV dilation->redness - allergic blepharoconjunctivitis - ret detachment - constricted pupil pulls all linked structures |
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Pilocarpine: Systemic Side Effects (6)
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- serious SEs assoc chronic use in glaucoma or overdose in acute treatment of angle closure
- bronchoconstriction - possible respiratory distress in asthmatics - GI upset - inc salivation and tearing - flushing and sweating - CNS effects - stimulation then depression - systemic cholinergic effects |
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Pilocarpine contraindications
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- PSCC - on axis tf dec vision w/ constriction
- <40yo - neovascular & uveitic glaucoma - - RD Hx - asthma - pregnancy B2, lactation |
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Lubricant uses (7)
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- dry eye Tx
- debris/allergen removal - contact agent - gonio etc - corneal regularity and VA improvement - OCT, topography - decrease preserved meds toxic effects - pre, intra and post refractive, cataract and corneal surgery - alleviate ocular discomfort |
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Ideal lube properties (9)
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- non-irritating
- good lubricating effect - long retention time - won't affect optics - won't remove essential substances from tears - contain beneficial substances - K bicarbonate and electrolytes - isotonic to tears - compatible with tear film components/layers - improve symptoms, TF stability and surface staining |
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Lube 'active' ingredients (6)
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- demulcents - mucolytic
- mucomimetic - enhance mucous properties - emulsifiers - mix oil/aqueous - surfactants - wetting agents - viscolizers - enhance viscosity - liposomes - enhance lipid properties (+preservatives & buffers - ph7.4) |
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Polymers/Viscolizers
- Low viscosity |
- for mild DE symptoms
- short retention time - frequent dosing - no blurring of vision on instilation - eg. Povidone, Murine Revital Eyes |
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Polymers/viscolizers
- High viscosity |
- prolonged residence
- high mucoadhesiveness - blur on instillation - poor shear thinning in tear deficient eye - PolyTears, PolyGel |
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Non-Newtonian polymers
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- synthetic gels
- high viscosity - shear thin with blinking - prolonged residence - less freq dosing - day and night use - eg carbomer gels, Luxyal |
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Mucomimetic lubes
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HP - guar
- gelling agent in solution with glycol 400 and propylene glycol - liquid form in bottle, gels with eye contact - preferentially binds more hydrophobic, dessicated of damaged areas - improved mucin layer -> temporary protection |
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Systane Lubes
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Ultra
- HP-guar +sorbitol Balance - HP guar + lipids/mineral oil SYSTANE Gel - thicker eye drop for severe symptoms - inc HP guar, inc gelling action |
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Liposome Lubes
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Tears Again - lid spray
- liposomes concentrate on lid margins and deliverd to ocular surface by blinking - delivers phospholipids, essential FAs, Vit E to lid - addresses lipid layer deficits - up to 95% Tear evap reduction - sigt NITBUT increase - up to 90min |
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Lube Osmolarity
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- hypotonic <340mOsm/L or isotonic
- increased tear osmolarity is a feature of all chronic TF and oc surface disorders -> morphological and biochemical changes to corneal and conj ep and pro-inflam |
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BAK in Lubes
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- preservative required in all multi-dose products to prevent microbial growth (TGA)
- toxic to corneal and conj ep - toxicity related to concentration, freq, tear secreation and clearance, oc surface severity - mild DE - well tolerated < 4xday - moderate DE - high potential for BAK toxicity |
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Lubricating ointments
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- contain paraffin and lanolin (can be irritant and delay wound healing, wool sensitivity)
- not well tolerated in severely aqu-deficient DE - avoid in MGD - generally unpreserved - night use |
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Lubricant dosage in DE
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Unit dose, preservative free
- > 4xday - in allergy, toxixity or severe tear deficiency Preservative - transient use - up to 4xday non-toxic |
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DE treatments
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- primary cause Tx
- tear supplements - drops day, gels night - ocular hygiene - lid scrubs - Omega 3 - AB drops/ointments - chlorsig - AI drops/ointments - FML, Hydrocor - Manuka Honey - Punctal plugs - Bandage CLs - Moisture Chamber goggles |
