RGP and conditions Flashcards
RGP cleaning
a. Daily surfactant, enzyme cleaner, polish, cleaning pad
b. Function: to remove loosely bound foreign matter, enhances disinfection action of soaking solution. With the use of silicone acrylate, greasing of lens surface has become a more frequent problem. Manufacturers have therefore created alcohol based solutions e.g. boston advance cleaner and cleaners with emollient and foam stabilisers e.g. total blink case
RGP rinsing
a. Rehydrates lens, dissolved enzyme tablets, removes cleaner, loosed deposits, microorganism, i.e. MPS e.g. lens plus ocupure
RGP reweting and conditioning solution
a. Wetting agents, viscosity enhancers, chelating agent, preservatives
b. Function – solution can be used on inserting to act as cushion between lens and cornea and enhances spread of tear film across cornea e.g. boston conditioning solution
RGP disinfecting
a. Kills or deactivates microbes left on the surface including bacteria, viruses, fungi, amoeba. Restores and maintains less hydration. It is a physical or chemical process. Can be done by heat or chemical i.e. oxidative or with cold chemical disinfectants.
b. Hydrogen peroxide disinfectant can be used in place of cleaning/rinsing or as an extra step i.e. once a week for really deep clean – or px with compliance/dexterity issues
RGP protein removers
a. Enzyme tablets to remove tightly bound protein deposits. Not necessary for every px, can be done once a week for those susceptible to deposits. E.g. boston one step liquid enzymatic cleaner
RGP soaking solution
a. Keeps lenses hydrated overnight in a sterile, bactericidal environment. Facilitates good wedding and saids in the material of deposits. Hydration is important to remain the correct BOZR in rigid lenses
b. e.g. B and L simplus solution
3 and 9 oclock staining aetiology
- Tear film breakdown and drying at the nasal and temporal areas of the cornea corresponding to the lens edge
- May result from the lens riding laterally on the cornea
- The staining increases overtime
- Causes include:
- Poor blinking
- Wide PAH
- Lens material – poor surface wetting properties
- Think edge design
- Spherical lens on a toric cornea
- Insufficient edge clearance
- TD too small
3 and 9 oclock staining symptoms
- Often asymptomatic
- Decreased wearing time
- Gritty red eyes
3 and 9 oclock staining signs
- Triangular area of epithelial punctate staining at 3 and 9 o’clock positions
- Nasal and temporal bulbar redness
- Tufts of vessels
- Severe – dellen, erosion/ulceration, vascularisation/scarring
3 and 9 oclock staining management
- Temporally discontinue wear
- Ocular lubricants while resolving
- Thinner lens
- Lid attached lens
- Alter lens periphery
- Increase TD >9.5
- Change to toric design
- Modify wear time
- Fit SCL
vascularised limbal keratitis aetiology
- Rare inflammatory rigid lens complication, with involvement of the conjunctiva, limbus and cornea.
- May occur secondary to 3 and 9 o’clock staining
- Causes include:
- Large TD lens
- Steep fitting with low edge lift
- Mechical abrasion
- EW or lid adherence
vascularised imbalance keratitis symptoms
- Minimal in early stages
- Gradual increase in discomfort, lens awareness, reduced wearing time
- Symptoms increase to redness, pain, photophobia, lacrimation
vascularised limbal keratitis signs
- evalated, slightly opaque epithelial lesion with ill defined borders (nasal or temporal)
- localized conjunctival injection – tufts of vessels
- limbal vessel engorgement
- corneal and conjunctival stainig
vascularised limbal keratitis management
- temporarily discontinue lens wear
- regular AC
- reduce wearing time
- lubricants and decongestants
- redesign lens – reduce TD, flatter BOZR to optimise edge lift
lid adhearance aetiology
- common after overnight wear and worse with a flat fitting lens
- may be due to limited movement of the lens and lid pressure
lid adhearance symptoms
- often asymptomatic
- mild awareness
- blurred vision
- dryness
- tiredness
- ocular pain
- FB sensation
- Spec blur following lens removal
lid adhearance signs
- Lens is bound to cornea and often decentred (usually nasal)
- Indentation and lens edge with corneal distortion
- Staining, increased at 3 and 9
lid adhearance management
- Alterations are unlikely to prevent adherence is susceptible wearers
- Patient education – assess, lubricants, mobilise lens with lid pressure
- Possibly fit lens with slightly Apical pooling
- Reduce TD
Bitot spots aetiology
- Build up of keratin debris located superficially in the conjunctiva
- Common in long term RGP wearers
- Associated with long term conjunctival drying secondary to bridging effect of lens
- Px may have a vitamin A deficiency
Bitot spots symptoms
generally assymptomatic, mild redness towards the end of the day.
Bitot spots signs
- Elevated conjunctival lesion
- White foamy area which may be oval/triangle or irregular in shape
- Located along the horizontal meridian
Bitot spots management
- Consider thinner lens
- Follow for changes in patient’s symptoms/appearance
Dellen
- Localised thinning of the cornea in a saucer like depression
- NaFl pooling due to localised tear film disturbance
- Long term consequence of desiccation
Dellen management
- Determine cause
- Minimise 3 and 9 staining
- Temporary discontinue lens wear and monitor recovery
- Ocular lubrication
corneal ulceration atielogy
- Uncommon in RGP wearers
- Failure to heed early warning signs
- Most common in EW
- Epithelial breakdown from other factors e.g. 3 and 9 or lid adherence
- Most ulcers are culture negative
Corneal ulcer symptoms
- Mild to severe pain/FB sensation
- Photophobia
- Tearing
- Redness
corneal ulceration signs
- Associated 3 and 9
- Underlying focal infiltrate in the anterior stroma with diffuse surrounding
corneal ulceration management
- Discontinue, eliminate 3 and 9 if precursor
- Chloramphenicol
- Generally will resolve with scarring
Dimple Veil Staining
- Gas or air bubbles trapped in a poor of tears beneath the CL can act as FBs
- They give dramatic appearance with NaFl but they are not true staining
- One lens is removed and eye rinsed, irregular depressions can be seen on cornea – small hemispherical pits in the epithelium
- May be due to poor lens/cornea relation i.e. too flat (more common) or too steep
- Px is general asymptomatic however may have a decrease in vision due to irregular topography
Dimple Veil staining management
- Alter fit
- Use non aerosol saline
