Astigmatism after penetrating keratoplasty using the Krumeich guided trephine system.

BACKGROUND: The use of a suction trephine during penetrating keratoplasty has the potential to reduce trephination errors and astigmatism after suture removal. METHODS: In this study, we evaluated refractive astigmatism after suture removal in 26 eyes that had penetrating keratoplasty for keratoconus using refraction, keratometry, and videokeratography. Group I (11 eyes) had manual trephination with an open disposable blade of both the donor (8.2 mm) and the recipient (8.0 mm). Group II (10 eyes) had manual trephination with an open disposable blade of the donor (8.2 mm) and Krumeich guided trephine system trephination of the recipient (8.0 mm). Group III (5 eyes) had guided trephination of both the donor (8.0 mm) and the recipient (8.0 mm). RESULTS: The guided trephine groups II and III demonstrated statistically significant less refractive cylinder when compared to manual trephination group I (p < .01). The mean keratometric cylinder for group I was 6.50 diopters (D) (range, 1.50 to 9.00 D), for group II was 3.00 D (range, 0.50 to 7.00 D), and for group III was 2.55 D (range, 0 to 4.00 D). CONCLUSION: The Krumeich guided trephine system produced less keratometric astigmatism than manual trephination after penetrating keratoplasty for keratoconus.

Effects of topical suprofen and flurbiprofen on the miosis produced by anterior chamber irrigation with cholinergic agonists.

Pretreatment with topical nonsteroidal anti-inflammatory drugs is common practice to maintain maximal pupil dilation for cataract surgery. Most surgeons also inject a cholinergic agent intracamerally for miosis after intraocular lens insertion. We evaluated the effects of topical suprofen and flurbiprofen on the miosis induced by anterior chamber irrigation with either acetylcholine or carbachol. One eye of 30 pigmented rabbits was dilated with cyclopentolate HCl and phenylephrine HCl. Three groups, each composed of ten eyes, received flurbiprofen, suprofen, or a control. In each group, five eyes received acetylcholine by anterior chamber irrigation and five received carbachol. Pupil diameters were measured with calipers before and five minutes after irrigation by an observer unaware of the treatment regimen. Irides irrigated with carbachol constricted less than those irrigated with acetylcholine (P = .016). In anterior chambers irrigated with carbachol, suprofen was associated with less miosis than either tears (P = .005) or flurbiprofen (P = .009); however, if the infusion was performed with acetylcholine, no differences between the three groups were noted (P = .44).

Reduction of cat eye movements using retrobulbar botulinum toxin.

We studied the effects of a single retrobulbar injection of Botulinum toxin on the motility of cat eyes. Four cats were sedated and the opposite eye served as a control. Eye movements were plotted by reflecting a laser beam from a mirror fixed to the cornea. We found the mean degrees of deviation per eye per day and summarized these results as mean degrees of deviation per eye per week +/- standard deviation. Statistical analysis was accomplished using Student's t test for independent measures, since measurement of the treated eye pairs was done in a randomized manner on different test days. (table; see text) These results indicate that a single retrobulbar dose of Botulinum toxin can produce a paralysis of the ocular musculature lasting in excess of four weeks in a specific and reproducible manner. In addition, this methodology should prove useful in future experiments in which ocular motility might prove to be a technical concern.

Evaluation of flurbiprofen-exposed irises to acetylcholine anterior chamber irrigation.

Flurbiprofen (Ocufen), an antiprostaglandin, has been introduced into cataract surgery. It is used to prevent intraoperative miosis by blocking inflammatory mediator formation. Ocufen has been noted to diminish the controlled miosis produced by using acetylcholine in the operative period. This study evaluated the pupillary response to acetylcholine after it had been exposed to Ocufen. This was done using a control versus a study eye in 16 rabbits dilated with phenylephrine hydrochloride and cyclopentolate hydrochloride. The pupil diameters were measured at baseline, then the rabbits' anterior chambers were irrigated with an acetylcholine solution. The resultant pupillary diameters were measured at one and five minutes. At five minutes post-irrigation there was a statistically significant greater constriction in the control group than in the Ocufen group. This implies that Ocufen dampens the iris musculature's response to acetylcholine.