Onlays and Inlays

Question 1

keratophakia - definition

Answer 1

plus-powered lens is placed intrastromally to increase the curvature of the anterior cornea to correct hyperopia, aphakia and presbyopia up to 20D

Question 2

KAMRA corneal inlay

Answer 2

improvement of near vision in presbyopic. nondominant eye. into an intrastromal pocket created by femtosecond laser. central aperture functions as a pinhole

Question 3

Epikeratoplasty

Answer 3

homoplastic lenticule directly onto the Bowman, “living contact lens” for patients with aphakia who were unable to wear contact lenses. hyperopia, myopia, and keratoconus

Question 4

Intrastromal Corneal Ring Segments- not only keratoconus

Answer 4

low myopia 1.00 to –3.00 D by displacing the lamellar bundles and shortening the corneal arc length

Question 5

Intrastromal Corneal Ring Segments-indications

Answer 5

low myopia , keratoconus and other forms of ectatic corneal diseases (ectasia after LASIK), residual myopia following LASIK (conversely, LASIK can be done after unsuccessful ring explantation)

Question 6

Intrastromal Corneal Ring Segments-what are they made of and where are placed

Answer 6

PMMA, are placed in the posterior midperipheral corneal stroma in a lamellar channel. The thicker the segment is, the greater will be the flattening of the central cornea and the reduction in myopia

Question 7

Intrastromal Corneal Ring Segments-how deep?

Answer 7

68%–70% stromal depth

Question 8

Intrastromal Corneal Ring Segments-reasons for 1) exchange 2) removal

Answer 8

1) residual myopia 2) glare, double vision, and photophobia

Question 9

beanbag effect

Answer 9

When a single segment is placed, it flattens the adjacent cornea but causes steepening of the cornea 180° away

Question 10

Intrastromal Corneal Ring Segments-criteria in keratoconus

Answer 10

progressive deterioration in vision such that the patient can no longer achieve adequate functional vision on a daily basis with contact lenses or glasses, - age 21 years or older, - clear central corneas, - a corneal thickness of 450 μm or greater at the proposed incision site, - a lack of options other than corneal transplantation for improving functional vision

Question 11

Orthokeratology

Answer 11

overnight use of RGP contact lenses to temporarily reduce myopia, fitted at a base curve that is flatter than the corneal curvature

Question 12

Orthokeratology-range of refraction

Answer 12

myopia between –0.50 and –6.00 D of sphere, with up to 1.75 D of astigmatism

Question 13

Orthokeratology-complications

Answer 13

induced astigmatism, induced higher-order aberrations, recurrent erosions, and infectious keratitis

Question 14

Orthokeratology-do patients like it?

Answer 14

one-third of patients discontinued contact lens use and 75% experienced discomfort at some point during contact lens wear