Lesson 13-Advanced Fitting Techniques Flashcards
Aphakia
An aphakic patient has had the crystalline lens removed.
Aphakia can occur after cataract surgery.
Arcus senilus
Whitish haze in the peripheral corneal stroma.
It is often associated with aging.
Aspheric surface
Can aid in lens-axis stabilization by adding drag to the motion of the lens.
This helps maintain the position of the lens during eye movement.
Coloboma.
A developmental defect of the eye occurring at the embryonic stage.
It can affect various structures of the eye.
Double Slab-off lenses
A lens thicker along its central body(along palperable fissure) and thinner along the superior & inferior edges(under the upper and lower lids).
This design helps in managing certain visual issues.
Keratoconus
A degenerative hereditary condition of the cornea characterized by progressive thinning of the central or paracentral area of the cornea, accompanied by irregular astigmatism.
It can lead to significant visual impairment.
Keratoglobus
A diffuse thinning of the cornea that can result in a ‘sagging cone’.
It is a more severe form of corneal thinning than keratoconus.
Keratoplasty
A surgery of the cornea; including corneal transplant and refractive surgery.
It is performed to restore vision or corneal integrity.
What does LARS stand for?
Left add, right subtract.
This is a method used for calculating lens power adjustments.
Monovision?
A technique for presbyopes where one lens corrects for distance and the other for near vision.
It is often used in contact lens fitting.
Ocular signs of age.
- Tear film abnormalities
- Reduced lid elasticity
- Lens opacities
- Loss of accommodation
These signs are common in older adults.
Penetrating keratoplasty (PKP)
The full thickness of the cornea is removed and replaced with donor tissue.
It is a common procedure for severe corneal disease.
Phoria.
A latent deviation (tendency) between the eyes.
It is only evident when fusion is broken.
Piggyback lenses?
Lenses used when the patient cannot tolerate rigid contact lenses & use of auxilary spectacles need to be avaoided.
They allow for better comfort and vision.
Posterior Toric Lenses
a back toric surface utilized as a lens stabilization technique.
This helps correct astigmatism.
Prism Ballast
A common stabilizing technique where a prism b/w 1.00D-1.50 D is ground base down into the lens.
This helps keep the lens in the correct position on the eye.
Pseudophakia?
An eye where the natural crystalline lens is replaced with a synthetic intraocular lens.
This often occurs after cataract surgery.
Rigid Aphakic Contact Lenses
These include the minus carrier lenticular lens and the single-cut lens.
These are designed for patients without a natural lens.
SEAL (Superior Epithelial Arcuate Lesion).
A thin, arcuate white lesion in the superior cornea, located within 1 to 3 mm of the superior limbus.
It typically appears between 10 and 2 o’clock.
Segment bifocal?
A design similar to a spectacle bifocal lens that shifts for reading.
patient casts gaze downward, the bifocal segment pushes up for reading
It allows for near and distance vision correction.
Single Cut lenses
In the ideal fit, these lenses will touch the apical cone lightly and come to rest on the peripheral cornea in an area where there is little or no thinning
They are used in fitting for keratoconus.
Soft (hydrophilic) lenses?
Lenses useful for keratoconus patients who cannot tolerate a rigid lens.
They provide comfort and better fitting.
Soper Keratoconus Diagnostic Fitting Set
Lenses designed with a steep base curve to accommodate the steep central cone area.
They have a flatter peripheral curve for better fit.
Tangent streak bifocal
A fused segment bifocal with a very large reading segment.
This design is beneficial for those needing significant near vision.
Thin lenses
a.k.a Dura-T-Lenses; they are characterized by a center thickness of about 0.08 mm.
Tropia.
A manifest(definate) deviation of the eyes.
Examples include esotropia (inward) and exotropia (outward).
Truncation (of a lens)
When a lens is truncated, a portion of it is sectioned off. It is usually 0.50 to 1.5 mm on the lower edge of the lens
This modification can aid in lens positioning.
