Comparison of Corneal Thickness Measurements with Optical Low Coherence Reflectometry, Orbscan System and Ultrasound Pachymeter

PURPOSE: To investigate the accuracy and reproducibility of Optical Low Coherence Reflectometry (OLCR) corneal thickness measurements compared with the Orbscan system and ultrasound pachymeter (IOPac, Mentor). METHODS: Two examiners measured corneal thicknesses of 78 normal eyes and in 36 eyes that had undergone LASIK, and five sequential measurements of corneal thickness with OLCR, Orbscan system, Mentor, and IOPac were performed. Remeasurements of corneal thickness in 24 normal eyes were performed after two days to investigate intra-examiner reproducibility. RESULTS: The average corneal thickness measured in normal subjects was 536.3+/-23.8 micrometer in OLCR, 542.4+/-25.3 micrometer in the Orbscan system, 535.4+/-23.7 micrometer in Mentor, and 534.2+/-24.1 micrometer in IOPac. The average corneal thickness measured in patients who had undergone LASIK was 487.3+/-30.8 micrometer in OLCR, 492.5+/-36.5 micrometer in the Orbscan system, 487.5+/-30.8 micrometer in Mentor, and 485.3+/-30.8 micrometer in IOPac. There was no statistically significant difference between the four pachymeters. The inter-examiner and intra-examiner reproducibilities were shown to be highly reliable. CONCLUSIONS: The OLCR showed similar measurments of corneal thickness with the Orbscan system and ultrasound pachymeter, and showed no difference in reproducibility with different examiners.

Results of Triple Surgery: Cataract Extraction, Intraocular Lens Implantation and Vitrectomy for Retinal Detachment

PURPOSE: To report the anatomic and visual results of triple surgery in patients with cataract and rhegmatogenous retinal detachment. METHODS: This retrospective study examined 11 cases of phakic detachment. All 11 eyes had both rhegmatogenous retinal detachment and cataract. For these, a triple procedure involving pars plana vitrectomy, cataract surgery and posterior chamber intraocular lens (PCL) insertion was performed. Intraocular lens (IOL) power calculation was performed in the diseased or both eyes. RESULTS: A clear intraoperative view of the fundus was obtained in all cases. The retina was reattached by triple surgery in 9 eyes. In one failed case, there had been extensive detachment with preoperative proliferative vitreoretinopathy grade C type 1. In the other case, retinal detachment recurred due to a new break. The two failed eyes obtained anatomic success by reoperation. Preoperative visual acuity (hand movement/10cm to 0.2) was improved (finger count/20cm to 0.8). There were 2 visual imbalances of -8.0 diopter and -10.0 diopter due to miscalculation of IOL power. CONCLUSIONS: In selective cases, combined triple surgery spares the patient repeat surgery and can offer a more rapid visual rehabilitation by clearly identifying the breaks and avoiding delays in detachment repair. To avoid miscalculation, IOL power must be calculated in both eyes, especially in cases of macular detachment.

Effect of Both Lateral Rectus Resection for Residual Esotropia

PURPOSE: To investigate the surgical outcome of both lateral rectus resection in the treatment of residual esotropia with previous both medial rectus recession METHODS: The medical record of 30 patients who had underwent both lateral rectus resection from 1996 to 2001 for residual esotropia occurred after bilateral medial rectus recession and who had followed up for more than one year, were analysed retrospectively. Successful outcome was defined as esotropia 0.05), but it was not significant statistically. Postoperative angle of deviation in group II was increased from 8.1+/-4.6PD at postoperative 1 day to 13.8+/-7.9PD at postoperative 1 year (p<0.001). CONCLUSIONS: Both lateral rectus resection is an effective method in the treatment of residual esotropia less than 40 PD.

Effect of Reverse Geometry Lens on Correction of Moderate-degree Myopia and Cornea

PURPOSE: To evaluate the effect of reverse geometry lens (RGL) on correction of moderate degree myopia and cornea in patients of moderate-degree myopia. METHODS: 48 eyes of 82 eyes were chosen to wear reverse geometry lens and the remaining 34 eyes were fitted with rigid gas permeable (RGP) lens. The subjects were tested three days, one, two weeks, one, two and three months after fitting the lens. Uncorrected visual acuity, manifested refractive error, corneal thickness and corneal endothelial cell count were evaluated. corneal topography were performed. RESULTS: The uncorrected visual acuity was increased at 0.05 LogMAR after two weeks. and manifested refractive error decreased during the first months, thereafter stabilizing to -0.2 D (diopters). Corneal thickness was 540.4 micrometer and 583.0 micrometer in the center and mid-periphery, decreased to 505.2 micrometer and 572.7 micrometer, respectively, three months after RGL fitting (p<0.05). Endothelial cell count was 2663.5 cells/mm2 and 2541.5 cells/mm2 in the center and mid-periphery, 3 months after RGL fitting and endothelial cell count was not significantly different compared with that of pre-fitting. There was no statistical difference between RGL fitting group and RGP fitting group in the change of corneal endothelial cell count. CONCLUSIONS: RGL was found to be effective in correction of moderate-degree myopia. It had minimal effect on corneal endothelium, in short-term usage, however, the change of corneal thickness suggests that RGL fitting may effect on corneal epithelium and stroma.

Effect of Both Lateral Rectus Recession in Large Angle Exotropia

PURPOSE: To evaluate of the effect of both lateral rectus recession according to the amount of the recession in the patients who showed large angle (>or=35 prism diopter, PD) exotropia. METHODS: The 120 patients who underwent both lateral rectus recession and followed up more than 1 year between 1996 to 2002 at Chung-nam university hospital, were reviewed. The effect of both lateral rectus recession was compared according to the amount of recession and preoperative angle of deviation. Successful outcome was defined as esotropia

The Effects of Placement of Silicone Tube and e-PTFE Stent in External Dacryocystorhinostomy

PURPOSE: To determine the surgical results of bicanalicular silicone tube and e-PTFE (expanded polytetrafluoroethylene) stent in external dacryocystorhinostomy without flap. METHODS: Sixteen patients had been placed with bicanalicular silicone tube and e-PTFE stent and 17 patients with silicone tube only in external dacryocystorhinostomy without flap. We examined the presence of epiphora symptom, passage of dye, and inflammatory change or granuloma formation of nasal mucosa at postoperative 1 day, 1 week, 2 weeks, 4 weeks, 8 weeks, 12 weeks, and 24 weeks. RESULTS: Success rate was higher in double stent group (81.3%) than that in control group (76.5%). But there was no statistically significant (difference between two groups. p=0.085). At nasal endoscopic examination, one case (6.3%) of granuloma was noted in double stent group, and two cases (11.8%) in control group. Membraneous obstruction was not observed in double stent group but one case (5.9%) in control group. CONCLUSIONS: In case of structural deteriolation of midface including nasolacrimal duct, placement of bicanalicular silicone tube with e-PTFE stent may be an useful method in external dacryocystorhinostomy without flap.

Comparison of Frontalis Sling and Levator Resection for Recurrence after Frontalis Sling in Congenital Ptosis

PURPOSE: To compare the success rate of two procedures frontalis sling operation and maximal levator resection for recurred congenital ptosis. METHODS: In the 44 eyes in 30 patients who had recurrence after frontalis sling using banked fascia lata, 21 eyes received frontalis sling operation using autogenous fascia lata (Group I), and the other 23 eyes received maximal levator resection with aponeurotic approach (Group II). Follow up was made at one month, three months, six months and one year after the operation. RESULTS: Six months after the operation, Group I showed 81.0% while Group II showed 78.3% in success rate. One year after the operation, Group I had 76.2%, while Group II had 73.9% in success rate. There were no significant statistical difference between the two groups (p=0.744, 0.707). CONCLUSIONS: In cases of recurrence after frontalis sling using banked fascia lata in treating congenital ptosis patients, we found the frontalis sling using autogenous fascia lata to be effective. The maximal levator resection may be used as an alternative procedure.

Clinical Results of LASIK Enhancement

PURPOSE: To assess the results of laser in situ keratomileusis (LASIK) enhancement by lifting the original flap and reablation for the treatment of myopic regression and undercorrection after initial LASIK. METHODS: We analyzed LASIK enhancement results in 19 patients (27 of 1026 eyes) which had myopic regression or undercorrection after initial LASIK. We evaluated the changes of refractive error, uncorrected visual acuity, best corrected visual acuity, corneal topography, and corneal thickness before and six months after enhancement. We also analyzed enhancement rate according to the original refractive error. RESULTS: Overall, the mean spherical equivalent (SE) was -7.10+/-1.78 diopters (D) before LASIK, -2.80+/-0.79D prior to enhancement and -0.31+/-0.46D at 6 months after enhancement (p<0.001). The uncorrected visual acuity at 6 months after enhancement was 1.0 or better in 10 eyes (37.0%) and 0.5 or better in 27 eyes (100%). Best corrected visual acuity (BCVA) did not change in 12 eyes (44.4%) and improved 1 line or more in 9 eyes (33.3%) at 6 months after enhancement. The final refractive error of one group which underwent enhancement within postoperative 3 month was closer to emmetropia than that of the other which had enhancement after postoperative 3 month, but there was no statistically significant difference (p=0.589). CONCLUSIONS: LASIK enhancement by using the original flap was an effective procedure, if the changes of refractive error were stable on refraction or corneal topography.

Change of Lipid Layer in Tear Film after Cataract Surgery

Several symptoms of dry eye in the patients who underwent cataract surgery are related to the stability of precorneal tear film layer. We studied the change of the lipid layer pattern in tear film after cataract surgery. Ninety-eight eyes of 87 patients were evaluated for the lipid layer patterns before operation and at two months after operation. Thirty-two eyes(32.7%) among 98 eyes had the change of the pattern of lipid layer. The change was more marked in the eyes of color fringe pattern preoperatively than others(p=0.000). The rate of change was not significantly different between the superior limbal incision group and temporal clear corneal incision group, and between the groups according to the number of sutures(p>0.05). The eyes which had had the dry eye symptoms developed more change of the lipid layer pattern(p=0.006). After cataract surgery, the change of the lipid layer pattern got more marked especially in the eyes which had had color fringe pattern before surgery. In the eyes which had had the dry eye symptoms, however, no difference was shown by the incisional site and by the number of sutures.

Ultrasonic Determination of Axial Length in Pseudophakia

To investigate the accuracy of ultrasonic measurement of axial length in pseudophakia, we measured axial length by ultrasonic scan at pre-and post-operatively.One hundred nine eyes of 97 patients were divided according to the type of intraocular lens.We compared pre-and post-operative axial lengths with Ocuscan[Alcon, U.S.A.]. The postoperative axial lengths were measured in phakic, aphakic, and pseudophakic mode.In pseudophakic mode, the velocity in IOL was set at the rate of 980, 2200 and 2718m/sec for silicone, acrylic, and PMMA lens respectively. The postoperative axial lengths in pseudophakic mode were closest to the preoperative values in all groups. In conclusion, we can get the closest values to preoperative axial lengths by setting the velocity in pseudophakic mode at the rate of 980, 2200 and 2718m/sec for silicone, acrylic and PMMA lens, respectively.

Orbital Cyst after Repair of Blow-out Fracture

When blow-out fracture repair is performed, many implants including Silastic, Supramid, Porous polyethylene and others have been used to pervent reherniation of orbital tissue. Complications associated with implants include implant extrusion, orbital infection, fistula formation, implant migration, extraocular muscle entrapment, globe elevation, protosis and orbital cyst formation. The latter was known as a rare late complication of blow-out fracture repair. We report two cases of orbital cyst which developed after blow-out fracture repair with alloplastic implants. These patients developed diplopia and unliateral proptosis 7 and 10 years after repair of blow-out fracture, respectively. In these cases, orbital CT scan revealed retrobulbar cyst-like structures surrounding the orbital implant. At sufgery, a fibrous capsule surrounded the previously inserted orbital implants and was filled with dark brown mucoid material in both cases. These cysts were lined by squamous epithelium with cholesterol cleft and hemosiderin laden macrophage collection. Proptosis and diplopia were resolved after surgical removal of the cyst. These cases illustrate that it is important for us to be aware of the complication of late cyst formation around alloplastic implants after repair of blow-out fracture.

Consecutive Esotropia Following Surgery for Intermittent Exotropia

Authors reviewed 459 cases which had been followed up over 3 months after surgery to evaluate the incidence of consecutive esotropia and its associated factors. For every case, we investigated the age at the surgery, the methods of surgery, stereopsis, cycloplegic refractive power, the deviation difference between far and near fixation, the deviation before surgery and the results at the postoperative 1 day, 1 week, 1 month, 4 months, 6 months, 1 year and 3 years. The incidence of consecutive esotropia tended to decrease as time passed, and occurred in 21 cases[4.6%] at the last follow-up[averaging 13.1 months]. When the deviation difference between at the distance and the near fixation was above 10 delta and the results at the postoperative 1 day was overcorrection above 10 delta, with significantly higher[p<0.05] incidence of consecutive esotropia. Other factors were not statistically significant. In conclusion, the preoperative factor was the far and near deviation difference above 10 delta and the postoperative factor was the first day postoperative overcorrection above 10 delta. It is considered that the nonsurgical treatment can be desirable for the former cases, and overcorrection above 10 delta should be avoided for the latter.

A roentgenographic study of the appearance of the hook of the hamate / 대한치과교정학회지

The author investigated the timing of land and wrist ossification events taking place in the hamate and pisiform by means of roentgenographic examination and its relation to the peak growth velocities in body height. Materials obtained included 493 sheets of X-ray films taken from 257 boys ana 236 girls aged between 7 and 17 years lived in Seoul area. The results indicate that; 1) The average ages at occurrence of initial ossification of the hook of the hamate were 12 years 3 months in boys and 10 years 1 month in girls. 2) The average ages at which advanced ossification of the hook of the hamate occurred were 13 years 7 months in boys and 11 years 11 months in girls. 3) Initial ossification of the pisiform appeared at 13 years 0 month in boys and 10 years 2 months in girls. 4) All three ossification events in hand and wrist, and peak growth velocity in body height occurred earlier in girls than in boys. 5) Initial ossification in the hook of the hamate and pisiform preceded or coincided with peak growth in body height in most boys and girls, on the other hand, advanced ossification in the hook of the hamate occurred around peak growth in body height but in girls did it after peak growth in body height. 6) It would appear that initial ossification in the hook of the hamate or in the pisiform, both for boys and girls, provides a better indication of approaching peak adolescent growth in body height. 7) Advanced ossification in the hook of the tamale would indicate that the period of cercumpuberal peak growth had teen entered or finished.

An experimental study of the stress relief of orthodontic wires / 대한치과교정학회지

No abstract available.