Lec 5 RGP complications Flashcards
Complications of tight RGP lens
Lens peripheral seal off so less tears/Lens adhere to cornea binding
Corneal indentation
NaFl staining outlining CL
Staining next to lens edge from rubbing
Central bubble/Cluster (dimple veil)
Symptoms of tight RGP
Lens discomfort
Ocular redness
Difficulty removing
Bubbles decreasing VA
How to treat tight RGP
Increase BC radius
Increase peripheral curve - edge lift
Widen peripheral curve
Decrease optic zone size
Complications of flat and loose RGP
Lens edge staining “jarring” on conjunctiva as motion
Central NaFl staining as motion
Draws in debris/FB/mucous under lens
Symptoms of flat and loose RGP
Lens discomfort and awareness
High lens dislodging rate
Visual fluctuation
High frequency of trapping FB and discomfort
How to treat loose RGP
Decrease BC radius
Decrease peripheral curve radius so increase edge lift
Decrease peripheral curve width
Increase optic zone diameter with lens diameter increase
Complications of high edge lift
Peripheral NaFl staining
FB tracking
Bubbles sucked under lens
Lens dislodges
Symptoms of high edge lift
Lens discomfort and awareness
High dislodging rate
Thing strapped under eye like dust
Lens moves too much
Treatment for high edge lift
Decrease peripheral curve radius so edge lift
Decrease peripheral curve width
Customise peripheral curves
Use toric periphery if excess edge lift in one meridian
Cause of dimple veiling
And sign
Steep central or high edge lift trapping bubbles and act as solids causing pits in epithelium
Pools NaFl
Irregular topography
Decreases vision if central
Treatment for dimple veiling
Decrease clearance by secreasing sag centrally or decrease edge flirt
Signs of Corneal insult/FB Tracking/Incidental abrasion
Localised corneal staining linked to cause
Material trapped behind lens
Injury direction to cornea
Symptoms of Corneal insult/FB Tracking/Incidental abrasion
Acute lacrimation
Discomfort till FB dislodged
Discomfort till cornea near healed
Etiology of Corneal insult/FB Tracking/Incidental abrasion
Lens mobility moves FB around under lens
Greater edge clearance means greater chance of getting FB under lens
Management of Corneal insult/FB Tracking/Incidental abrasion
Stop CL wear temporarily for min to hrs - recovery within hrs if superficial
Irrigate if multiple FB in eye - check lid
Prophylactic broad spectrum AB for deeper abrasions
Signs of corneal warpage from constant high or low riding CL
Corneal topography distorted so irregular astig so dec VA
Acuity with CL better than specs
Lens positioned high or low on eye and indentation pattern
Possible oedema
Symptoms of corneal warpage from constant high or low riding CL
Asymptomatic (masks)
Complains spec vision not good
HX shows no ownership of any glasses
Long hours wearing CL
Findings for corneal warpage
Distorted keratometry mires
Irregular retinoscopy results
Indecisive subjective refraction
Reduced BCVA in spectacles +spec blur
How to manage corneal warpage
Change lenses with increased transmissibility OR stop CL
Repeat refraction and topography every 1-2wks till changes stabilise
Slowly withdraw original lenses and fit with softer lenses and FINAL Refit with improved lens centration and more 02
SPECIAL TALK!
What’s the SPECIAL TALK for corneal warpage management
Need to convince them they need to change
Ensure they have updated glasses to prevent heavy reliance on CL
Let them know the new CL uncomfy as corneal sensitivity returns
RESIST request to return to old lens haha
What’s the cause of 3&9 o’clock staining (peripheral corneal staining)
Lens edge meniscus and local tear film thinning
What’s lens bridging
When the eyelid gets lifted away from the globe creating a vacuum so dries out an area creating staining in outer portions
What are some factors for 3 and 9 o’clock staining
Reduced blink rate, partial blinker, poor tears
Long CL hours, CL wettability
CL thick edge/edge defect
Excess clearance as dries out neighbouring area OR low edge clearance as digs
How to treat 3&9 o’clock Staining
Patient education
Tear supplements/Improve blinking
Redesign lens to improve fitting
Maximise lens wettability and minimise surface deposits
What’s Dellen
Localised thinning of cornea in saucer like depression that pools with NaFl
Happens due to paralimbal elevation causing a break in precorneal oily tear layer so dehydrated and thins
What contributes to dellen
Elevations (ping/ptery/RGPedge)
Chronic tear film evaporation
Post operation (IOL implant/subconjunctival injection/bleb surgery)
Chronic 3 and 9 o’clock staining
How to manage dellen
Stop RGP temporarily to allow reepithelisation and corneal thickness to return
Lubricate
Manage cause
Whats vascularised limbal keratitis
Opaque elevated mass at nasal/temp cornea next to limbus due to mechanical insult from RGP edge SO usually from large diameter lens with low edge lift
What’s RGP induced ptosis
Lowering of upper lid to reduce the palpebral aperture over time in an RGP wearer with associated swollen red lids
Common causes of RGP induced ptosis
Lid traction during lens removal
Mechanical interaction of lid riding over the lens
Inflammation
How to treat RGP induced ptosis
Stop CL wear for 4-12 weeks
Refit with SCLs
Review lens edge profile to be more thin and tapered
Lid surgery
What are the main CL integrity problems
Lens curvature warping
Edge defect/sharpness
Front surface issues - scratches/deposit adherence/poor surface wetting
Signs of lens warping
NaFl pattern of CL weird
Vision reduced
BC readings abnormal and mires didn’t focus on a single point
BVP differnt than original
Causes of lens warping
Heavy handling
Cleaning between thumb and forefinger
Pressing lens against lens case
Along it to dry out with solution residue
Management of lens warping
Verify using radisucope
Replace lens -can make it thicker/stronger
Re-educate in handling
Signs of edge defect/sharpness
Can see defect of lens edge
Tactile rim feels sharp
Lens rip poorly rounded
Conjunctival jarring staining
Management of edge defect/sharpness
Polishing rolling of lens edge
Increasing thickness if edge thin
Ordering new lens if significant defect
Signs of front lens surface issues
Scratches
Crazing
Lens surface non wetting so patchy dry surface
Deposits
Sources that cause non wetting on a Cl
Over polished surface
High wetting angle material
Contamination with lanolin
Old CL
Complications with lens surface issues
Increase risk for bacterial adhesion as now surface irregular
Increase risk for conjunctival surface irritation as eye lid blinks over irregular surface
Discomfort and stop wearing lens
Risk for staining and redness
What’s lid wiper epitheliopathy
Upper lid is subjected to higher then normal frictional force due to lack of tears OR lens surface with high coefficient of friction
What’s CL Induced Papillary Conjunctivitis
CLPC
Commonly due to mechanical irritation of lens causing inflammation of superior tarsal conjunctiva = large papillae
Process of papillae formation in CLPC
Antigen in CL causes vessel changes/hyperaemia
Basophils and mast cells accumulate and release ECF-A that attracts eosinophils
Eosinophils release histamine causing itch, erythema and edema
Compare structure between papillae and follicles
Papillae in CL wear but follicles not related
Papillae cobblestone like/hyperaemic with central vascular tuft BUT follicles translucent pale elevated rice grain shaped and avascular
Papillae 0.3-0.9mm follicles are 0.2-2mm
Papillae superior palpebral conj VS follicles inferior
Papillae VS follicles physiology
Papillae chronic VS follicles not
papillae seen in normal conj VS follicles not seen normally
Papillae mainly inflammatory cells VS follicles are local aggregation of lymphocytes
Papillae mucus strands VS follicles Not
Management of CLPC
Stop/minimise wear
Manage cause e.g thinner lens, deposit care, replace lens, edge shape, overwear
Therapeutics like histamine blocker, MCS, combo stabiliser and antihistamine, mild steroid if more chronic
Sources of infiltrates
Bacterial toxins
Tight lens
Trauma
Eye closure with lens
Poor hygiene e.g hand wash after smoking
Poor disinfection
What are sterile infiltrates
Inflammatory cells that migrate from limbal BVs
What’s solution toxicity/hypersensitivity
Ocular surface exposed to chemical agent in CL solution that’s toxic to epithelial causing diffuse staining over cornea and acute or chronic redness
Common causes of solution toxicity or hypersensitivity
Mercury based thimerosal
Chlorhexidine
Benzalkonium chloride
Changing solutions recently
Management of solution toxicity
Remove CL
Irrigate
Change solution to diff preservative
