1.Analysis of Higher-Order Wavefront Aberrations in Standard PRK.
Sang Bumm LEE ; Byeung Hun CHOI
Journal of the Korean Ophthalmological Society 2005;46(9):1454-1463
PURPOSE: To investigate the preoperative characteristics and postoperative change of the higher-order wavefront aberrations (HOAs) in myopic photorefractive keratectomy (PRK). METHODS: Standard PRK was performed in 39 eyes (spherical equivalent -4.71+/-1.56D) using the VISX(R) STAR S4(TM) excimer laser system. Wavefront analysis was performed preoperatively and 6 months postoperatively using the VISX(R) WaveScan(TM) aberrometer. Statistical analysis was performed to assess the preoperative characteristics of the HOAs and the PRK-induced aberrations. RESULTS: The preoperative root mean square (RMS) value of the total HOAs was 0.291 micrometer: coma 0.159 micrometer, trefoil 0.157 micrometer, spherical aberration 0.093 micrometer. Among the 3 HOAs, only the spherical aberration showed moderate magnitude negative correlation with the spherical equivalent (p=0.012) and sphere (p=0.005). The magnitude of all of the HOAs, except trefoil, were significantly increased at postoperative 6 months: total HOAs 183% (0.533 micrometer, p<0.001), spherical aberration 341% (0.317 micrometer, p<0.001), coma 185% (0.294 micrometer, p<0.001), trefoil 104% (0.163 micrometer, p=0.681). In the postoperative correlation analysis, only the PRK-induced spherical aberration showed the increase of magnitude with increasing preoperative spherical equivalent (p=0.036) and sphere (p=0.019). CONCLUSIONS: The HOAs, especially spherical aberration and coma, were increased after PRK. Among the 3 HOAs, the spherical aberration showed the greatest increase of magnitude and percent change; it also showed a positive correlation with increasing preoperative spherical equivalent and sphere. Further software improvements in the wavefront-guided surface ablations need to have a diminution of PRK-induced spherical aberration.
Coma
;
Lasers, Excimer
;
Lotus
;
Photorefractive Keratectomy
2.Correction of Superior Sulcus Deformity and Enophthalmos with Porous High-density Polyethylene Sheet in Anophthalmic Patients.
Byeung Hun CHOI ; Sang Hyeok LEE ; Wha Sun CHUNG
Korean Journal of Ophthalmology 2005;19(3):168-173
PURPOSE: Superior sulcus deformity is the main cosmetic problem in anophthalmic patients. Many methods of correcting enophthalmos have been reported, especially in patients with orbital wall fracture. The purpose of this study is to review the long term results of effectiveness in superior sulcus deformity correction by subperiosteal Medpor (R) sheet implantation in anophthalmic patients. METHODS: Subperiosteal Medpor (R) sheets were used in 11 eyes of 11 anophthalmic patients. To estimate the effectiveness, photographs were taken and exophthalmometric value with their own prosthesis using Hertel exophthalmometer was measured in all patients before and after surgery. RESULTS: The overall cosmetic results in superior sulcus deformity were 'excellent' in 3 (27.3%), 'good' in 6 (54.5%), 'fair' in 2 (18.2%). The overall results in enophthalmos were 'excellent' in 3 (27.2%), 'markedly improved' in 4 (36.4%), 'slightly improved' in 4 (36.4%). Most patients had a marked increase in orbital volume, except two patients. They received irradiation treatment in early childhood so showed unsatisfactory results in both superior sulcus deformity and enophthalmos. CONCLUSIONS: Subperiosteal Medpor (R) sheet implantation is considered to be a reliable and safe procedure without serious complication and with an excellent cosmetic results.
*Surgical Mesh
;
Surgery, Plastic
;
Retrospective Studies
;
*Polyethylene
;
Middle Aged
;
Male
;
Humans
;
Female
;
Eyelid Diseases/*etiology/*surgery
;
Enophthalmos/*etiology/*surgery
;
Child
;
Anophthalmos/*complications
;
Adult
;
Adolescent