[A study on the effects of different keratectomies for astigmatism in rabbits' eyes].
Three kinds of wedge resections with sutures at limbus were carried out in grown rabbits. Keratometry was performed for 8 weeks. Corneal curvature and corneal astigmatism were not significantly changed by 90 degrees of the circumference. But in the group of 180 degrees resection, the radius perpendicular to the wound increased and 3. 5 D corneal against-the-rule astigmatism was brought about in a week after surgery. Therefore, when operated at the limbus by same extension, one longer wedge resection changed more the radius than 2 symmetric resections did. It was thought this against-the-rule astigmatism was due to the decrease of total surface, another side of the wound being sclera, and other factors. They are properties of suture material, the provoked tissue reaction, and so on. Pulling on domed tissue should be looked at again. Loss of effect was remarkable. So, to get permanent effect, we should study more about the time of suture removal, acting over the sclera and the sutures penetrating cornea. Secondly, two kinds of keratectomies perpendicular to vertical meridian were situated midway between limbus and corneal apex. The changes of total refractive power were followed up by skiascopy for 3 months. As a result, 1.0 D-1.5 D against-the-rule astigmatism was surgically induced in both keratectomies. This was almost due to myopic change of the opposite meridian, which was parallel to the resections. Loss of effect of rectangle-shaped keratectomy was less than that of crescent-shaped. It suggested cutting Ligamentum Circulatum situated near limbus was necessary to prevent the reduction of induced astigmatism with time. In addition, limbus of wedge resection was histologically observed. Markedly wavy appearance of lamellas was seen in the stroma. Like this, reactions to 8-0 virgin silk proved to be intensive. So, suture associated with less inflammatory reaction like 10-0 monofilament is recommended.
Teranishi
C
C
Department of Ophthalmology, Nayoro City Hospital, Japan.
D000818:Animals; D001251:Astigmatism / Q000473:pathology / Q000503:physiopathology / Q000601:surgery*; D003315:Cornea / Q000473:pathology / Q000601:surgery*; D007646:Keratotomy, Radial; D008722:Methods; D011817:Rabbits; D013536:Suture Techniques