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4 Contact Lens > Lec 5 RGP complications > Flashcards

Lec 5 RGP complications Flashcards

1
Q

Complications of tight RGP lens

A

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)

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2
Q

Symptoms of tight RGP

A

Lens discomfort

Ocular redness

Difficulty removing

Bubbles decreasing VA

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3
Q

How to treat tight RGP

A

Increase BC radius

Increase peripheral curve - edge lift

Widen peripheral curve

Decrease optic zone size

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4
Q

Complications of flat and loose RGP

A

Lens edge staining “jarring” on conjunctiva as motion

Central NaFl staining as motion

Draws in debris/FB/mucous under lens

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5
Q

Symptoms of flat and loose RGP

A

Lens discomfort and awareness

High lens dislodging rate

Visual fluctuation

High frequency of trapping FB and discomfort

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6
Q

How to treat loose RGP

A

Decrease BC radius

Decrease peripheral curve radius so increase edge lift

Decrease peripheral curve width

Increase optic zone diameter with lens diameter increase

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7
Q

Complications of high edge lift

A

Peripheral NaFl staining

FB tracking

Bubbles sucked under lens

Lens dislodges

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8
Q

Symptoms of high edge lift

A

Lens discomfort and awareness

High dislodging rate

Thing strapped under eye like dust

Lens moves too much

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9
Q

Treatment for high edge lift

A

Decrease peripheral curve radius so edge lift

Decrease peripheral curve width

Customise peripheral curves

Use toric periphery if excess edge lift in one meridian

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10
Q

Cause of dimple veiling

And sign

A

Steep central or high edge lift trapping bubbles and act as solids causing pits in epithelium

Pools NaFl

Irregular topography

Decreases vision if central

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11
Q

Treatment for dimple veiling

A

Decrease clearance by secreasing sag centrally or decrease edge flirt

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12
Q

Signs of Corneal insult/FB Tracking/Incidental abrasion

A

Localised corneal staining linked to cause

Material trapped behind lens

Injury direction to cornea

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13
Q

Symptoms of Corneal insult/FB Tracking/Incidental abrasion

A

Acute lacrimation

Discomfort till FB dislodged

Discomfort till cornea near healed

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14
Q

Etiology of Corneal insult/FB Tracking/Incidental abrasion

A

Lens mobility moves FB around under lens

Greater edge clearance means greater chance of getting FB under lens

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15
Q

Management of Corneal insult/FB Tracking/Incidental abrasion

A

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

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16
Q

Signs of corneal warpage from constant high or low riding CL

A

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

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17
Q

Symptoms of corneal warpage from constant high or low riding CL

A

Asymptomatic (masks)

Complains spec vision not good

HX shows no ownership of any glasses

Long hours wearing CL

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18
Q

Findings for corneal warpage

A

Distorted keratometry mires

Irregular retinoscopy results

Indecisive subjective refraction

Reduced BCVA in spectacles +spec blur

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19
Q

How to manage corneal warpage

A

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!

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20
Q

What’s the SPECIAL TALK for corneal warpage management

A

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

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21
Q

What’s the cause of 3&9 o’clock staining (peripheral corneal staining)

A

Lens edge meniscus and local tear film thinning

22
Q

What’s lens bridging

A

When the eyelid gets lifted away from the globe creating a vacuum so dries out an area creating staining in outer portions

23
Q

What are some factors for 3 and 9 o’clock staining

A

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

24
Q

How to treat 3&9 o’clock Staining

A

Patient education

Tear supplements/Improve blinking

Redesign lens to improve fitting

Maximise lens wettability and minimise surface deposits

25
Q

What’s Dellen

A

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

26
Q

What contributes to dellen

A

Elevations (ping/ptery/RGPedge)

Chronic tear film evaporation

Post operation (IOL implant/subconjunctival injection/bleb surgery)

Chronic 3 and 9 o’clock staining

27
Q

How to manage dellen

A

Stop RGP temporarily to allow reepithelisation and corneal thickness to return

Lubricate

Manage cause

28
Q

Whats vascularised limbal keratitis

A

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

29
Q

What’s RGP induced ptosis

A

Lowering of upper lid to reduce the palpebral aperture over time in an RGP wearer with associated swollen red lids

30
Q

Common causes of RGP induced ptosis

A

Lid traction during lens removal

Mechanical interaction of lid riding over the lens

Inflammation

31
Q

How to treat RGP induced ptosis

A

Stop CL wear for 4-12 weeks

Refit with SCLs

Review lens edge profile to be more thin and tapered

Lid surgery

32
Q

What are the main CL integrity problems

A

Lens curvature warping

Edge defect/sharpness

Front surface issues - scratches/deposit adherence/poor surface wetting

33
Q

Signs of lens warping

A

NaFl pattern of CL weird

Vision reduced

BC readings abnormal and mires didn’t focus on a single point

BVP differnt than original

34
Q

Causes of lens warping

A

Heavy handling

Cleaning between thumb and forefinger

Pressing lens against lens case

Along it to dry out with solution residue

35
Q

Management of lens warping

A

Verify using radisucope

Replace lens -can make it thicker/stronger

Re-educate in handling

36
Q

Signs of edge defect/sharpness

A

Can see defect of lens edge

Tactile rim feels sharp

Lens rip poorly rounded

Conjunctival jarring staining

37
Q

Management of edge defect/sharpness

A

Polishing rolling of lens edge

Increasing thickness if edge thin

Ordering new lens if significant defect

38
Q

Signs of front lens surface issues

A

Scratches

Crazing

Lens surface non wetting so patchy dry surface

Deposits

39
Q

Sources that cause non wetting on a Cl

A

Over polished surface

High wetting angle material

Contamination with lanolin

Old CL

40
Q

Complications with lens surface issues

A

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

41
Q

What’s lid wiper epitheliopathy

A

Upper lid is subjected to higher then normal frictional force due to lack of tears OR lens surface with high coefficient of friction

42
Q

What’s CL Induced Papillary Conjunctivitis

CLPC

A

Commonly due to mechanical irritation of lens causing inflammation of superior tarsal conjunctiva = large papillae

43
Q

Process of papillae formation in CLPC

A

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

44
Q

Compare structure between papillae and follicles

A

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

45
Q

Papillae VS follicles physiology

A

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

46
Q

Management of CLPC

A

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

47
Q

Sources of infiltrates

A

Bacterial toxins

Tight lens

Trauma

Eye closure with lens

Poor hygiene e.g hand wash after smoking

Poor disinfection

48
Q

What are sterile infiltrates

A

Inflammatory cells that migrate from limbal BVs

49
Q

What’s solution toxicity/hypersensitivity

A

Ocular surface exposed to chemical agent in CL solution that’s toxic to epithelial causing diffuse staining over cornea and acute or chronic redness

50
Q

Common causes of solution toxicity or hypersensitivity

A

Mercury based thimerosal

Chlorhexidine

Benzalkonium chloride

Changing solutions recently

51
Q

Management of solution toxicity

A

Remove CL

Irrigate

Change solution to diff preservative

4 Contact Lens (11 decks)

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