Comparison of Corneal Thickness Measured by Specular, US Pachymetry, and Orbscan in Post-PKP Eyes

PURPOSE: To compare the accuracy and reproducibility of central corneal thickness measured by non-contact specular microscopy, ultrasound pachymetry, and Orbscan in the post-penetrating keratoplasty eyes. METHODS: Central corneal thickness was prospectively measured in eyes that had recieved penetrating keratoplasty at least 1 month before. One experienced technician measured all eyes using three methods; non-contact specular microscopy (Topcon SP-2000P; Topcon Corporation, Tokyo, Japan), Orbscan IIz (Orbtek; Bausch & Lomb, Rochester, USA), and ultrasound pachymetry (AL-2000; Tomey, Erlangen, Germany). Three consecutive measurements were performed using each method and the mean values and coefficient of variation were compared. RESULTS: The mean values of central corneal thickness were 550.7+/-63.3 micrometer with specular microscopy, 548.2+/-72.5 micrometer with ultrasound pachymetry, and 472.5+/-151.7 micrometer with Orbscan. There was no significant difference between the measurements obtained by specular microscopy and ultrasound pachymetry (p=0.53), and both methods showed high reproducibility. The corneal thickness measured by Orbscan was remarkably variable and in some patients, Orbscan was unable to measure corneal thickness. CONCLUSIONS: Non-contact specular microscopy appears to be an effective technique, potentially replacing ultrasound pachymetry for measuring central corneal thickness in the post-penetrating keratoplasty eyes.

Antielevation Syndrome after Unilateral Anteriorization of the Inferior Oblique Muscle

PURPOSE: To report antielevation syndrome with restriction of elevation on abduction in the operated eye and overaction (OA) of the inferior oblique muscle (IO) of the contralateral eye after unilateral IO anteriorization (AT). METHODS: Medical records were reviewed retrospectively in 8 of 24 patients who underwent unilateral IOAT. Four patients were referred from other hospitals after the same surgery. RESULTS: Four patients had infantile esotropes. The rest showed accommodative esotropia, superior oblique palsy, exotropia, and consecutive exotropia. The mean amount of hyperdeviation was 16.3 PD (10~30). The mean restriction of elevation on abduction in the operated eye was -1.6 (-1~-4) and IOOA of the contralateral eye was +2.7 (+2~+3). IOAT of nonoperated eyes in 4 patients, IO weakening procedure of anteriorized eyes in 2 patients, and IO myectomy on an eye with IOAT in 1 patient were performed. Ocular motility was improved after surgery in all patients. CONCLUSIONS: Unilateral IOAT may result in antielevation syndrome. Therefore bilateral IOAT is recommended to balance antielevation in both eyes. A meticulous caution is needed when performing unilateral IOAT.

Inadvertent Ocular Perforation during Lid Anesthesia for Hordeolum Removal

PURPOSE: Ocular perforation during lid anesthesia is rarely reported. We describe here a case of inadvertent corneal perforation and traumatic cataract that occurred during lid anesthesia in a procedure for hordeolum removal. METHODS: A 33-year-old woman presented with a sudden visual loss of her left eye. She had undergone hordeolum removal the day before at a local clinic. On ophthalmologic examination, the cornea was perforated and the lens cortex was extruded into the anterior chamber. After cataract removal and IOL implantation, antibiotics were injected into the vitreous. RESULTS: Her final visual acuity of the left eye was 20/20. Postoperative specular microscopic examination revealed a normal-range endothelial cell count, coefficient of variation, and hexagonality despite the intracameral lidocaine injection. CONCLUSIONS: Anesthetic injection of an infected lid should be done with great caution. Although there are possibilities of corneal endothelial toxicity and endophthalmitis in case of intracameral lidocaine injection through the infected lid, yet proper management may save the patient's vision without complications.

Accuracy of Corneal Thickness Measurement with Ultrasound Pachymeter in Thin Corneas

PURPOSE: Accurate assessment of corneal thickness is important in order to prevent iatrogenic corneal ectasia after laser in situ keratomileusis (LASIK). More accurate measurement is needed in LASIK enhancement because the cornea becomes thin after previous refractive surgery. We evaluated the reliability of corneal thickness measurement with ultrasound pachymeter (USP) in the thin corneas. METHODS: The corneal thickness was measured in the 22 eyes of 11 rabbits. The corneal flap was made with an Automated Corneal Shaper microkeratome (Bausch and Lomb, USA) with 130 micro meter plate and the flap was removed in order to make the cornea thin. Residual stromal bed (RSB) thickness was measured with USP and thickness gauge, and the two measurements were compared. RESULTS: Mean corneal thickness was 404.69 +/- 11.01 micro meter with USP and 133.23 +/- 15.66 micro meter with thickness gauge. RSB thickness measured with thickness gauge was 269.05 +/- 24.19 micro meter and this was not significantly different from the expected RSB thickness, although RSB thickness measured with USP was 388.14 +/- 10.17 micro meter, which was significantly different from the expected RSB thickness (p=0.00). CONCLUSIONS: In the thin corneas, corneal thickness measurement with ultrasound pachymeter is not reliable.

Influence of Peripapillary Atrophy on the Progress of Diabetic Retinopathy

PURPOSE: To evaluate the influence of peripapillary atrophy on the progress of diabetic retinopathy. METHODS: Interval between the diagnosis of diabetes and the onset of diabetic retinopathy was compared between 77 eyes of 50 patients with peripapillary atrophy and 253 eyes of 172 patients without peripapillary atrophy who visited the Korea university ophthalmology department between January 2002 and May 2002, No one had glaucoma or high myopia. Pepipapillary atrophy was classified by severity and compared. RESULTS: Time to the onset of nonproliferative diabetic retinopathy was longer in the patients with peripapillary atrophy (13.7 years) than the patients without peripapillary atrophy (11.2 years) (p

Influence of Orbit Size and Interorbital Distance on Development and Outcome of Surgery for Intermittent Exotropia

PURPOSE: To evaluate the influence of orbital size and interorbital distance on the development and recurrence of intermittent exotropia. METHODS: We selected 55 intermittent exotropes(group A), 30 esotropes (group B), and 30 normal children(group C). Width and height of orbit, inner interorbital distance (IIOD), and outer interorbital distance (OIOD) in both orbits were measured with skull A-P(Anterior-Posterior) roentgenogram, and orbital index (IIOD/OIOD X 100) was calculated. The cephalometric results of the 6 recurrent exotropes and the 6 consecutive esotropes in group A were analyzed too. RESULTS: There is no significant difference in orbital height and orbital length among 3 groups. The IIOD was 25.0+/-3.86 mm in group A, 21.9+/-3.95 mm in group B, and 22.7+/-4.34 mm in group C. Mean OIOD was 100.3+/-9.75 mm in group A, 97.0+/-8.96 mm in group B, and 98.4+/-5.61 mm in group C. Orbital index was not different with the increase of age (p=0.23). It was greater in group A (25.0+/-2.79) than that in group B (22.9+/-2.66) and group C (23.1+/-2.79) (p<0.05). Orbital index of the orthophoric children after strabismus surgery in group A was 24.7+/-2.99. It was greatest in the 6 recurrent extropes (25.2+/-2.00) and was smallest in 6 the consecutive esotropes (23.5+/-1.69) CONCLUSIONS: Intermittent exotropia is more prevalenat in subjects with longer IIOD and greater OI, and esotropia is more prevalent in subjects with shorter IIOD and lower OI. The possibility of recurrence after surgery was high in patients with greater OI, and the possiibility of consecutive esotropia was high in patients with low orbital index.