NACOR Slides Section 2 Flashcards
9.
Spherical RGP on a toric cornea
secondary (foreign body under RGP)
Remove and clean see if removes foreign body
20.
High riding lens
Correct High riding lens by:
- Increase lens Diameter
- Increase Center Thickness
- Decrease lens diameter
- Decrease edge thickness
- Flatten Base Curve
- Use prism ballast design
5.
Dimple vailing / lens too steep
Indentations of the epithelium resulting from air bubbles (under RGPs) or Mucin balls (under soft lenses). Most often seen with steep fitting RGPs.
Symptoms: None- mild irritation, may disturb vision if on visual axis.
Signs: Indentations display un-reversed illumination with white light. Multiple, focal areas of fx pooling
Refit closer to the corneal shape. Flatter BOZR, smaller diameter or change to toric back surface.
7.
Three Point Touch
2.
Corneal Neovascularization
If the cornea does not receive adequate oxygen and nourishment, blood vessels will grow past the limbus into the corneal tissue. Usually associated with over-wear of contact lenses causing corneal hypoxia.
Deep (stromal) vascularization is more sever than Superficial (epithelial) vacularization.
Remove lenses for several weeks, refit with lenses that let through more oxygen
Referal dependant on how sever the vascularization is
16.
Edge Standoff/ Inside out soft
check if inside out, refit larger lens if necessary
Three methods for increasing the edge lift of a rigid aspheric lens design follow:
The posterior apical radius remains constant and the diameter is increased.
The posterior apical radius is made flatter and the diameter remains constant.
The posterior apical radius is made flatter and the diameter is increased.
Three methods for decreasing the edge lift of a rigid aspheric lens design follow:
The posterior apical radius remains constant and the diameter is decreased.
The posterior apical radius is made steeper and the diameter remains constant.
The posterior apical radius is made steeper and the diameter is decreased.
12.
Dendric Ulcer
A dendritic ulcer has many fingers that look like the branches of a tree. Herpes simplex commonly infects the face and mouth. In some people the virus from a cold sore can be transferred to the eye and affects the cornea.
Referral
4.
Blepharitis
Referral
Blepharitis is a chronic inflammation of the margis of the eyelids. It is very common and can be caused by several factors: staphylococcal infections of the base of the lashes or dysfunction of the meibomian glands. Common in px with acne, rosacea and seborrhea.
Symptoms: Grittiness, itching and burning, redness of the lid margins and conjunctiva, stickiness and lid crusting. Worse upon waking. Dandruff like scaling, eyelashes missing or misdirected. Tear film maybe frothy and unstable, lid margins and conjunctiva appear red.
Can cause degenerative changes in the skin and conditions such as meibomitis, chalazion and corneal complications such as scarring and marginal keratitis.
11.
Giant Papillary Conjunctivitis (GPC)
GPC, unlike other types of conjunctivitis, is caused by the presence of foreign material in the eye such as contact lenses or artificial eyes. It is characterized by giant cobblestone-shaped papillae on the superior tarsus of the upper lid.
Remove contacts for several weeks (have polished)
19.
Munson’s sign
Keratoconus
referral if patient unaware
Munson’s sign which is identified as an indentation of the lower lid by the corneal cone with inferior gaze. The medical sign is characteristic of advanced cases of keratoconus and is caused by the cone-shaped cornea pressing down into the eyelid.
10.
Herpes Zoster Ophthalmicus
Referral ASAP
Typically presents with facial pain, fever and general felling of fatigue and not feeling well for a few days before the rash appears. The rash forms small blisters along the distribution of the fifth (trigeminal) cranial nerve, along one side of the nose, lid brow and sometimes into the head. Characteristically the vertical mid-line is not crossed. the blisters or small ulcers erupt, discharge fluid and begin to scab over. the pain is extreme during the inflammatory stage and patients are extremely symptomatic.
Ocular involvement is common when the rash involves the side and tip of the nose. These include: conjunctivitis, episcleritis, acute iritis, keratitis, corneal lesions, optic neuritis, and extra ocular muscle paralysis.
1.
Chalazion
referal
A chronic inflammation of a blocked meibomian gland. Swelling of the lid, usually painless, no infection. Vision may be blurred or distorted if it is large.
One or more hard, painless nodules in the upper or lower eyelid. There may be a painful infection prior to nodules appearing. Can be a recurrent condition, esp if the px has poor lid hygiene practices or blepharitis.
13.
Low Riding soft lens
To correct a low riding lens:
- Increase diameter.
- Decrease diameter
- Decrease center thickness
- Back surface toric or bitoric lens design may be used.
- Steepen base curve
- Flatten base curve
- A minus carrier design may be used.
15.
Piggyback
“Piggyback” contact lens fitting techniques involve using some form of conventional or disposable soft contact placed on the cornea with a rigid gas permeable lens placed on top. This modality may be used for hypersensitive patients who will not tolerate wearing just the RGP lens or recurrent corneal irritation caused by mechanical interaction (such as central corneal scarring or due to poor tear volume or quality) with the RGP lens.
This modality helps to give your irregular corneal patient a more stable and regular shell on which to fit the RGP lens.
If the RGP lens moves too much, rides superiorly, nasally or temporally or rocks on the apex of the cone, choose a soft lens with more minus lens power to effectively tighten the fit of the RGP lens (this will not affect the correction already determined for the RGP lens).
If the RGP lens is too steep or rides too low, choose a soft lens with more plus lens power to effectively loosen the fit of the RGP lens.
8.
Subconjunctival Hemorrhage
When a small capillary under the conjunctiva breaks or ruptures, blood spreads, leaving a prominent red-sheet patch that can last up to two weeks or more. The hemorrhage is often caused by a sudden rise in venous pressure from extended bouts of coughing or sneezing or sudden straining. It can be a sign of systemic disease such as hypertension or certain bleeding disorders, as well. Usually a subconjunctival hemorrhage is monocular.
If a patient has a binocular hemorrhage, referral should be made to a medical doctor for further investigation. Subconjunctival hemorrhages can be as small as a dot or may spread to cover the total conjunctiva. Often the cosmetic appearance, because of the spread of blood under the conjunctiva, becomes worse before beginning to resolve. This is a benign, self-limiting condition when not associated to systemic illness and the prognosis is excellent, although for the patient having a subconjunctival hemorrhage, it can be quite alarming.
17.
Iris Coloboma
Occasionally, in utero, the iris does not completely form, as can happen with any other part of the body. It is an absence of iris tissue resulting in a keyhole shaped pupil. The missing iris tissue is usually seen in the inferior nasal position. This is a congenital condition and is not a common occurrence.
3.
Hyphema
(blood in the anterior chamber)
Blood in the anterior (front) chamber. Caused by an injury, may partially block vision. May also occure spontaneously without trauma. Spontaneous hyphemas are usually caused by neovascularazion, tumors or other vascular anomalies. Conditions or medications that cause thinning of the blood.
URGENT assessment by optometrist or Ophthalmologist.
6.
Pterygium
Pterygia is a non-malignant, slow-growing proliferation of the conjunctival connective tissue. It is a triangle-shaped hyaline overgrowth of conjunctiva that crosses the limbal border and may interfere with vision if growth is sufficient.
Refer If a ptergium interferes with vision removal is necessary
18.
Graft and Sutures
Corneal graft or transplant is most frequently performed to enhance the integrity of the central cornea. The reasons for performing corneal grafts include keratoconus, corneal scarring due to trauma or infection, Fuchs dystrophy, central corneal scarring or bullous keratopathy. Penetrating keratoplasty is most commonly done for keratoconus patients whose corneal apex have thinned to a significant degree or for elderly patients who have developed problems with intraocular implants. The transplant is performed using donor tissue, usually managed by an eye bank and involving long waiting times until donor tissue becomes available.
Usually about 7.5 to 8 mm of the central cornea is removed and a slightly larger section of donor cornea is stitched into place. The sutures may not be removed for 6 months to a year and the donor tissue may not allow stable vision for about the same amount of time.
There are possible complications ranging from minor (such as fluid leaks or raised pressure) to major which can jeopardize sight or loss of the eye (fortunately theses incidences are rare). There is also the risk of tissue rejection which is normally successfully treated with steroids of varying strengths. The last and smallest risk is the transmission of disease. Donor tissue is tested for hepatitis and AIDS but other viruses and germs may get through. Graft failures generally look milky with very blurred vision and can be due to any of the above, plus infection, endothelium breakdown or return of the original disease.
You will find that many corneal graft patient’s host or original tissue will be steeper than the donor tissue because the graft tissue is inserted very slightly larger than the opening and this causes the host tissue to be pushed out and makes the graft flatter than the original.
If by chance the corneal graft is protruding or steeper than the original tissue, consider fitting a small diameter spherical or aspheric lens inside the graft. This is often caused because the donor graft button was too large which forced it to bulge forward. A lens of about 7.5 mm in diameter, just enough to allow some movement will be needed. The lens will usually ride on the junction of the graft in the inferior position. The key is to ensure the lens doesn’t fall out easily and that you do not have too much pressure on the steepest zone, much like a keratoconus cornea.
14.
Bulbous Keratopathy
Refer ASAP
Bullous keratopathy is most common in older people and occurs after surgery, such as cataract removal. The swelling leads to the formation of fluid-filled blisters on the corneal epithelium. A condition that often concurs with bullous keratopathy is stromal edema, which is caused by a compromise in the endothelial cell pump mechanism. Vision loss can be mild to severe and pain is associated with the blisters on the surface of the cornea.
