Outcome of delayed adjustable strabismus surgery in children using a bow-tie optional adjustable technique

Purpose: The aim of this article is to study the feasibility of a delayed adjustable technique of strabismus surgery in children using an optional adjustable suture technique. Methods: The retrospective study included patients <12 years of age. Recessions were done using an optional adjustable bow-tie technique and resections were done by the conventional technique. Patients were evaluated on the third postoperative day and adjustments done when needed. Statistical analysis was done using Microsoft Excel 2010�. Results: The study included 11 patients with exotropia and 16 patients with esotropia. The mean age of the patients was 5.2 years (range 1� years). The mean preoperative distance deviation was 46.7 � 10.4 prism diopters (PD) for exotropic patients and 47.1 � 16.9 PD for esotropic patients. The mean preoperative near deviation was 46.6 � 11 PD for exotropic patients and 52.4 � 17.1 PD for esotropia. Two patients with exotropia (18.2%) and four patients with esotropia (25%) were adjusted under intravenous ketamine in the operating room under anesthetist supervision. No difficulty was encountered in advancing/recessing the muscles. The success rate at 1 month was 100% for exotropia and 87.5% for esotropia. The success rate at the final follow-up was 81.8% for patients with exotropia and 68.7% for patients with esotropia. Conclusions: This delayed optional adjustable strabismus surgery technique provides good short-term results and lower adjustment rates.

Effect of Preoperative Corneal Symmetricity on Clinical Results in Myopic Excimer Laser PRK

We compared postoperative visual outcome and corneal refractive power depending on preoperative corneal topographic pattern and the predictibility of corneal topographic measurement compared with keratometric measurement after PRK. The subjects were 91 eyes divided into two goups composed of 44 eyes, symmetric bow tie type(SB) and 47 eyes, asymmetric bow tie type (aSB). The visual acuity, central power, and topographic pattern were measured before operation, postoperative 1 week, 1, 2 and 6 month in two groups, but no statistical difference(p>0.05). The averages of uncorrected visual acuity at 6 month were improved to 0.80(SB) and 0.85(aSB) from 0.09(SB) and 0.11(aSB) before operation. Topographic central refractive powers of +42.98D (SB), +43.32D(aSB) before operation were changed to +37.68D(SB), 37.56D(aSB) at 6month. The pattern of the region affected by the excimer laser was classified by key hole type 38%(SB) , 34%(aSB) , uniform roud type 41%(SB), 43%(aSB), semicircular type 21%(SB), 23%(aSB). The proportion of the difference less than one diopter between PRK setting and the change of the corneal refractive power at 6month was 36% and 76% in keratometric and topographic measurement. Above results show that the asymmetricity of bow tie type did not influence the visual outcome. The topographic measurement was better than keratometric measurement in evaluating the corneal refractory change after PRK.

Classification of Corneal Topography and Analysis of Astigmatism based on Computer-Assisted Videokeratography

We evaluated the corneal topography of 109 eyes which have 1 diopter or more astimatism, with computer-assisted videokeratography(Eye Sys CAS). There was 11% with round pattern, 17.4% with oval pattern, 49.5% with symmetric bow-tie pattern, 19.3% with assymmetric bow-tie pattern, 2.8% with irregular pattern. 70% of subjects had right and left eyes classified into the same group. There was statistically significant difference among the patterns for keratometric astigmatism and difference among the groups which were classified by the location of the area of highest refractive power for keratometric and total astigmatism. The mean angular separation between flat and steep meridian was 89.2 degrees and ranged from 78.61 degrees to 100.67 degrees. The mean residual astigmatism was 0.547 diopter. In the with-the rule astigmatism type, when the total astigmatism less than 1.89 diopter, residual astigmatism neutralize the corneal astigmatism, but when the total astigmatism increase more than 1.89 diopter, residual astigmatism tend to increase the total astigmatism.