ABSTRACT
PURPOSE: To evaluate posterior corneal surface elevation after LASIK in relation to the residual stromal bed thickness and the ablation percentage. METHODS: 363 eyes that underwent LASIK were examined retrospectively. The range of their refractive error was from -1.5 to -10.0 D. We obtained their corneal topography with Orbscan II and pachymetry preoperatively, and at one week, one month, two months, and three months postoperatively. The patients were divided into four groups based on the residual stromal bed thickness: Group I; 145 eyes with less than 250 micrometer, Group II; 129 eyes with 250~300 micrometer, Group III; 79 eyes with 300~350 micrometer, and Group IV; 13 eyes with more than 350 micrometer. We also grouped them based on the ablation percentage per total corneal thickness: Group A; 16 eyes with less than 10%, Group B; 166 eyes with 10~15%, Group C; 149 eyes with 15~25%, and Group D; 35 eyes with more than 25%. RESULTS: The extent of increase in the post-LASIK posterior corneal surface elevation correlates with residual corneal bed thickness and the ablation ratio per total cornea. In contrast, posterior corneal elevation values for Group IV were 0.025+/-0.005 mm preoperatively, 0.038+/-0.007 mm at 1 weeks, 0.037+/-0.010 mm at 1 month, 0.03+/-6 0.012 mm at 2 months, 0.036+/-0.009 mm at 3 months. In Group A, the values at the same times were 0.029+/-0.009 mm, 0.043+/-0.012 mm, 0.039+/-0.013 mm, 0.040+/-0.013 mm, 0.038+/-0.010 mm. CONCLUSIONS: The extent of increase in the post-LASIK posterior corneal surface elevation correlates with residual corneal bed thickness and the ablation ratio. There were no statistically significant changes in postsurgical posterior corneal surface elevation, however, if the residual corneal thickness remained more than 350 micrometer or the ablation percentage was lower than 10%.
Subject(s)
Humans , Cornea , Corneal Topography , Keratomileusis, Laser In Situ , Refractive Errors , Retrospective StudiesABSTRACT
PURPOSE: To determine the intraocular pressure (IOP) lowering effects on the change of anterior chamber depth (ACD), corneal thickness, corneal cell area and density in normal eyes. METHODS: We investigated 58 eyes of 29 volunteers for this study whose refractive error was +/-3 D, IOP was below 21 mmHg, anterior segment and fundus was within normal limit. All of them had normal visual fields. They were randomly classified into two groups. Anterior chamber depth, IOP, central corneal thickness, cell density, cell area, and coefficient of variation of corneal endothelium were measured by single observer in each group. After oral medication of 50% glycerin 1 cc/kg (body weight) in group 1 and Diamox 500 mg and K-contin 600 mg in group 2, IOP, anterior chamber depth, central corneal thickness, cell density, cell area, and coefficient of variation were measured at 1, 2, and 3 hours. RESULTS: In glycerin group after 1 hour, decreased IOP was stastically significant (P0.05). There was no significant correlation between decreased IOP and the change of anterior chamber depth, central corneal thickness, cell density, cell area, and coefficient of variation. The IOP change was not statistically different between the two groups. CONCLUSIONS: There was no stastically significant correlation between decreased IOP in normal range and the change of ACD, central corneal thickness, cell density, cell area, and coefficient of variation.
Subject(s)
Acetazolamide , Anterior Chamber , Cell Count , Endothelium, Corneal , Glycerol , Intraocular Pressure , Reference Values , Refractive Errors , Visual Fields , VolunteersABSTRACT
Restriction of eye movement after surgery is an unusual but troublesome complication. A patient presented with a limitation of abduction after a 5 mm resection of medial rectus muscle and an 8 mm recession of lateral rectus muscle. Since the forced duction test was positive, restrictive factors were suggested to be implicated. A reparative operation was performed at the postoperative 9 month, and the forced duction test was negative after releasing the resected medial rectus muscle. The patient showed an improved abduction after recessing the resected muscle. Even after an uneventful surgery, resection of an extraocular muscle may cause restriction of ocular rotation caused by muscle scarring to the sclera or by an increased tightness of the muscle.
