Dispensing in sport Flashcards
What does sports eye wear aim to do ?
- improve vision by -enhancing contrast and reducing glare
- provide protection via impact resistance and UV protection.
What are the main hazard for racket sports glasses?
-Squash ball travels at high velocity- 140mph but up to 176mph
-Squash ball is approx. 40mm diameter
-Injuries due to racquet sports represent 47.5% of ocular trauma
that required hospital admission
- therefore need to make sure frames and lenses need to provide protection
What protects the orbital socket from damage ?
- bone structure- facial bones in nose, cheek and forehead- if hit by a football suppose.
- however a squash ball is small enough to fit within the socket
What injuries do racquet sports cause?
- involve blunt trauma
- Blunt trauma
- Blow out fracture
- Ruptured globe- push eyeball intro circuit
- Hyphema
- Retinal haemorrage
- Retinal detatchment -Commotio retinae
What are the 2 British standard for racquet sports ?
- Must conform to EN167 and EN166 (Personal eye protection). Squash- BS7930:1
What are the rules for racquet sports?
- Now mandatory for all doubles squash players and juniors to wear protective eyewear.
- Cant be worn over specs.
How racquet sports glasses can be made?
- Can be glazed with Rx
- Glazed ‘loose’ to allow impact to be absorbed by glasses
What to consider when giving racquet sports glasses?
wide field of view
What do the racquet sport frames designed as ?
being padded to help absorb any shock and help prevent bruising.
-Thick silicone molded cushion pads to protect the nose on
impact.
-Elasticated headbands instead of standard sides.
-Can be ventilated to prevent streaming up
-Should be adjustable for good fit
-Commonly nylon
What are the lenses of racquet sports glasses made of ?
- Polycarbonate for impact resistance
- Coated for anti-fog
- Can be high base curve if curved- can change base curve of lens so they can fit in a certain frame
What are some things to consider for snooker glasses?
- Head position
- Effect on vision
What should the frames of snooker glasses be like ?
-Must have joint angles to allow for retroscopic and Pantoscopic
tilt
-Dispensers rule for retroscopic tilt Raise the heights by half of
the retroscopic angle.
What should the lenses of snooker glasses be like ?
-Require 50mm depth- great depth- so need be of large blanc size
-MAR
-The visual axes must still be approximately
the lens.
What needs to be considered for shooting glasses ?
- Eye dominance- whether they prefer one eye - occluded or not- ask what type of shooting they err doing.
- Contrast
- Lenses
- Tints- colour? how dark?
- Lenses can be tilted and centered according to the shooters position.
- The non shooting eye can be occluded.
What tints are good for shooting glasses ?
bronze tint- often used in clay pigeon shooting
- yellow tint- good in shooting on black and white target- good contrast
- red and pink tint- good for black and green targets- reduce effects of green background
What can. the frames be like on shooting glasses ?
-Can be hung from a mount -Can include a pinhole- reduce aberrations and increase how well px are seeing.
What does a darker tint mean ?
-less light is reaching the eye-
the pupil will expand more to let light in- this is less preferable for shooting because we want the pupil to be small as possible acting as pinhole itself.
1§-the px may prefer the lighter tent hence.
What are the British requirements for skiing goggles?
- UV requirements BS EN 12312 - protect against UV-
- polarised glasses not good for this-as may not be able to see changes in contour
- should have high Impact resistance
- Tints, which colour and why? -Rx!
- Polarizing
Why do we require UV protection for skiing goggles (BS)?
-the snow itself is highly reflective and can cause photo keratitis and snow blindness - the British standards for skiing goggles- in extremely high luminance conditions such as snowfall or desert , which under full sunlight the use of category 4 filters may be recomended- LTF of 15% (darker tints)
What are the frames of skiing goggles like ?
- can be glazed- often have removable inset for glazing
- adjustable headband to help the glasses stay on when they are skiing
What are the tints usually used on lenses on the skiing goggles?
grey tint- often used as It keeps very true to colours as it reduces visible light through all spectrums equally
-yellow or rose filters- filter out blue lights- preferred by px
What are the lenses like on skiing goggles?
- mirror coatings- provide extra protection from UV
- transitions- some px like as they work well in cold environment
- anti-fog
How can swimming goggles be glazed?
- by providing clip in lenses for the frame surrounding it
- generally plano concave or convex- so that the curvature is all place on the back surface and isn’t influenced by the surrounding media
- the lens maker equation -assumes in air- but r.i of water is different to air- by glazing the curves on the back surface that isn’t touching water-it is easier to glaze these lenses
What do the clip in lenses come in ?
come in standard spherical prescriptions
- may not work with px with high cyls
- better to use a near match to px prescription than their exact prescription
- spherical power -2 - 6 are available
What are some things to consider as a diving mask ?
- Pressure changes - when changing in water
- Watertight fit
- Frame
- Can be full or half mask
- Silicone seal- used in watertight seal
- good seal- could be occluded or clear- which provide some peripheral Vision
- dark seal- can reduce internal reflections
What types of lenses to give to a diving mask ?
- Tempered glass- as they dont react badly under pressure changes under water
- Can have rx insert- glazed with rx
What are some things to consider with cycling or running ?
Impact resistance
- Smaller debris (dust, insects) -UV protection
- Glare protection
- FOV- lenses with a higher base curve- increases FOV - even though it isn’t perfect in periphery they will still know if anything come around .
- Contrast enhancement (yellow tint can be popular)
What are the frames like in cycling or running?
- Require excellent fit
- Lightweight
- Detachable sides
- interchangeable lenses
What are the lenses like in cycling or running?
-Polycarbonate for impact resistance
-Wrapped- so consider base curve to increase FOV and off axis
performance
-Contrast enhancing tints
