Journal of refractive and corneal surgery最新文献

Background: The purpose of this study is to investigate retrospectively the visual function of eyes 1 year after photorefractive keratectomy.

Methods: Visual function was assessed in 34 eyes of 22 patients who had undergone excimer laser surgery (Summit Excimed UV200). The mean time after surgery was 12.3 months. Twenty eyes of 20 age-matched normal subjects served as controls. The following tests were used: high and low contrast logMAR visual acuity, Pelli-Robson contrast sensitivity, and straylightmeter scores at 3.5 degrees and 10 degrees.

Results: There was a significant difference between scores obtained for the photorefractive keratectomy population and the control (p < .001, ANOVA). Fifty-six percent (18/32) of the excimer treated eyes fell outside the 95% confidence limits of the normal data in at least one test of visual function; 22% (7/32) fell outside in at least 3 out of 5 tests.

Conclusions: Some eyes showed reduced visual function 1 year after excimer surgery compared to age-matched normal controls. These deficits can only be detected fully when psychophysical tests in addition to visual acuity are employed.

Background: Corneal neovascularization is a common clinical entity. Although visual acuity is usually impaired and corneal function compromised, there has been only limited success in the clinical management of this condition. We evaluated the efficacy of laser photocoagulation of neovascularization in the rabbit cornea.

Methods: New vessel formation was provoked by the placement of sutures in the corneas. Rose bengal was injected intravenously and new vessels in the upper part of the corneas were treated with an argon laser. The lower halves were used as controls. Eighteen rabbits were divided into 2 groups. In group A neovascularization was treated 28 days after suture removal, when corneal inflammation had regressed. In group B treatment was performed 3 days after suture removal, when the cornea still exhibited marked inflammation. Postoperatively, the corneas were studied by slit-lamp microscopy, fluorescein angiography, and light, as well as electron microscopy.

Results: In group A, treatment led to the immediate occlusion of the vessels and to their gradual disappearance during the course of 3 months. In group B, no occlusion was seen during the 3-month follow-up period. The main histologic findings in the occluded vessels were endothelial cell disruption and degeneration, and the formation of clots.

Conclusion: Our results suggest that argon laser photocoagulation using rose bengal is an effective method of occluding corneal new vessels, providing there is no corneal inflammation at the time of treatment.

Background: Refractive error is assessed in the seated position while keratorefractive procedures are performed in the supine position. Since position-induced ocular torsion could yield suboptimal results from improper axis alignment, this study was undertaken to ascertain whether ocular cyclotorsion occurs when a subject moves from a seated to supine position.

Methods: Fifty eyes of 29 subjects with refractive cylinder greater than 0.50 diopters were enrolled. Refraction was done with a phoropter and the correction was placed in a trial frame using plus cylinder. Astigmatic axis was determined in the seated and supine positions for 32 eyes by utilizing the "rocking the cylinder" technique and for 32 eyes using the Jackson cross cylinder. Both techniques were used for 14 eyes.

Results: No statistically-significant difference for cylinder axis measured in the seated versus supine position was observed using the rocking the cylinder (4.3 degrees standard deviation [SD], 3.5 degrees, range 0 degrees to 13 degrees, p = NS) or the Jackson cross cylinder methods (2.3 degrees, SD, 1.9 degrees, range 0 degrees to 7 degrees, p = NS). Approximately 25% of eyes had a change in axis of 7 degrees to 16 degrees.

Conclusions: These data suggest that the cylinder axis does not change significantly or predictably when most subjects move from the seated to supine position. The Jackson cross cylinder method seems more accurate and reproducible than the rocking the cylinder technique in determination of astigmatic axis under these circumstances.