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49. Safety and effectiveness of keratophakia and keratomileusis.
1
UI - 86305515
AU - Werner DL
TI - Refractive surgery: keratomileusis and keratophakia.
AB - This paper reviews the non-radial keratotomy surgeries that are being
performed. The author reviews the literature and suggests an approach
toward counseling patients who may be considering these approaches. The
paucity of reported studies makes the choice of these alternate
procedures somewhat risky, particularly in their refractive
predictability.
MH - Cornea/*SURGERY/TRANSPLANTATION ; Evaluation Studies ; Forecasting ;
Human ; Myopia/PHYSIOPATHOLOGY/SURGERY ; Postoperative Complications ;
Refraction, Ocular ; Refractive Errors/PHYSIOPATHOLOGY/SURGERY ; Visual
Acuity
SO - J Am Optom Assoc 1986 Aug;57(8):590-3
2
UI - 86277263
AU - Swinger CA ; Candia OA ; Marcus S ; Barker BA ; Kornmehl EW
TI - Epithelial ion transport in rabbit corneas following myopic
keratomileusis.
AB - In isolated rabbit corneas that had undergone lamellar keratectomy or
myopic keratomileusis, the stimulation of chloride transport by 10(-5) M
epinephrine was completely inhibited at 1 week following surgery. At 28
days following surgery, both groups responded to 10(-7) M epinephrine.
The response to 10(-5) M amphotericin B was normal both at 1 week and at
28 days following surgery. We conclude that, although the Na-K pump was
not affected by the lamellar keratectomy and cryolathing, that either the
epithelial beta receptors and/or the cAMP pathway were temporarily
inhibited for at least 1 week following surgery. A lamellar keratectomy,
therefore, can have an adverse effect on the epithelial transport system
of the corneal epithelium even though the epithelium may appear normal
clinically.
MH - Adenosine Cyclic Monophosphate/METABOLISM ; Amphotericin B/PHARMACOLOGY ;
Animal ; Biological Transport, Active ; Chlorides/METABOLISM ; Cornea/
*METABOLISM/SURGERY ; Epinephrine/PHARMACOLOGY ; Epithelium/METABOLISM ;
Ion Channels/DRUG EFFECTS/*METABOLISM ; Myopia/*SURGERY ; Rabbits ;
Receptors, Adrenergic, Beta/METABOLISM ; Support, U.S. Gov't, P.H.S.
SO - Invest Ophthalmol Vis Sci 1986 Aug;27(8):1277-80
3
UI - 86159621
AU - Beekhuis WH ; McCarey BE ; Waring GO ; van Rij G
TI - Hydrogel keratophakia: a microkeratome dissection in the monkey model.
AB - High water content intracorneal implants were fabricated from Vistamarc
hydrogel (Vistakon, Inc.) at 58%, 68%, and 72% water content and a range
of powers from +7.25 to +17.00 dioptres. The Barraquer microkeratome
technique was used to implant the lens at 59.0 +/- 9% (+/- SD) depth in
the corneas of 14 rhesus monkey eyes. The contralateral eye served as a
control. Three eyes were lost to the study because of complications. The
remaining 11 animals were followed up for 51 +/- 2 weeks with the
refractive yield being 118 +/- 34% and the keratometric yield being 92
+/- 30%. The measured and theoretically expected refractive changes have
a linear regression line correlation coefficient of 0.74, whereas the
respective keratometric data had a correlation coefficient of 0.04. The
measured refraction became stable within 2 to 3 dioptres after 20
postoperative weeks. The hydrogels were well tolerated within the corneal
tissue. There was a minimum of interface problems except along the edge
of the implant. Implants with abruptly cut edges versus a fine wedge
tended to have more light scattering collagen at the implant margin.
MH - Animal ; Biocompatible Materials ; Cornea/ANATOMY & HISTOLOGY/*SURGERY ;
Female ; *Lenses, Intraocular ; Macaca mulatta ; Male ; Methods ;
*Polyethylene Glycols ; Refraction, Ocular ; Support, Non-U.S. Gov't ;
Support, U.S. Gov't, P.H.S. ; Time Factors
SO - Br J Ophthalmol 1986 Mar;70(3):192-8
4
UI - 86159620
AU - McCarey BE ; van Rij G ; Beekhuis WH ; Waring GO 3d
TI - Hydrogel keratophakia: a freehand pocket dissection in the monkey model.
AB - High water content hydrogels can be made with water and solute
permeabilities comparable to those of the corneal stroma, thus making
them feasible as intrastromal implants for refractive keratoplasty. The
materials have been shown to be compatible with the cornea tissue, but
for a lenticule of hydrogel to be effective in a refractive keratoplasty
procedure it must alter the anterior curvature of the cornea. In this
investigation hydrogel lenticules were implanted by a free-hand pocket
dissection in eight Macaca mulatta (rhesus) and two Macaca nemestrina
(pigtail) primate eyes. The results of pre- and postoperative keratometry
and subjective retinoscopy as well as biomicroscopy were recorded. The
alteration in refractive power was calculated in relation to the hydrogel
lenticule parameters such as base curve, refractive index, etc. The
corneal refractive change had a yield of +3 +/- 27% (+/- SD). The central
keratometric change had a yield of +6 +/- 16%. The hydrogel plus power
lenticule implanted in a free-hand intrastromal pocket created no
significant steepening of the anterior cornea surface and therefore
little change in refraction.
MH - Animal ; Biocompatible Materials ; Biometry ; Cornea/ANATOMY & HISTOLOGY/
*SURGERY ; *Lenses, Intraocular ; Macaca mulatta ; Macaca nemestrina ;
*Polyethylene Glycols ; Refraction, Ocular ; Support, Non-U.S. Gov't ;
Support, U.S. Gov't, P.H.S.
SO - Br J Ophthalmol 1986 Mar;70(3):187-91
5
UI - 86130113
AU - Bornfeld N ; Hoffmann F ; Mellin KB ; el Hifnawi ES ; Waubke TN
TI - Ultrastructure of the rabbit corneal stroma after experimental
keratomileusis.
AB - Experimental keratomileusis operations were performed on 13 rabbit eyes.
The corneas of the rabbits, in particular the stroma, were investigated
up to 24 months after the operation by light and electron microscopy. The
most striking features of the corneal ultrastructure following
experimental keratomileusis were the presence of abnormal collagen
fibrils and electron-translucent vacuoles in the interface.
MH - Animal ; Cornea/*SURGERY/*ULTRASTRUCTURE ; Corneal Stroma/*ULTRASTRUCTURE
; Microscopy, Electron ; Microscopy, Electron, Scanning ; Rabbits
SO - Arch Ophthalmol 1986 Feb;104(2):253-8