Sang Min Nam

Accuracy of RTVue Optical Coherence Tomography, Pentacam, and Ultrasonic Pachymetry for the Measurement of Central Corneal Thickness

OBJECTIVE To compare the reliability and the agreement in measuring central corneal thickness (CCT) using the following technologies: RTVue Fourier-domain optical coherence tomography (Optovue, Inc., Fremont, CA), Pentacam (Oculus, Inc., Wetzlar, Germany), and ultrasonic pachymetry (USP; Pocket-II; Quantel Medical, Inc., Bozeman, MT). DESIGN Evaluation of diagnostic test. PARTICIPANTS One hundred four eyes of 52 healthy subjects (mean age ± standard deviation, 28.6 ± 4.8 years). METHODS One eye from each subject was assigned randomly for a repeatability test in which a single operator performed 3 successive measurements. The other eye underwent an interoperator reproducibility test by 3 operators. Two centering methods of RTVue and 3 types of CCT from Pentacam were investigated. For USP, 1 drop of topical anesthetic was administered, and measurement was initiated 90 seconds later. Agreement among the instruments was evaluated using Bland-Altman plots. MAIN OUTCOME MEASURES Various types of CCT were compared: central zone average and minimum thickness of RTVue centering on the vertex and the pupil; corneal thickness at the pupil center, apex, and thinnest location from Pentacam; and mean CCT of 5 repeated measurements of USP. The reliability of measurement was assessed using the repeatability or reproducibility coefficient (Rco), the coefficient of variation, and the intraclass correlation coefficient. The limit of agreement was used to analyze concordance. RESULTS The Rco of RTVue was 4 to 5 μm, which was comparable with that of USP and better than that of Pentacam (10-11 μm). The Rco was not dependent on centering methods (RTVue) or types of CCT (Pentacam). The location of minimum thickness found by RTVue was less reliable than that of the Pentacam. The central zone average of RTVue was approximately 7 μm larger than the pupil center or apex thickness of Pentacam and approximately 13 μm larger than the CCT measurement of USP. Those discrepancies could be as high as 20 and 23 μm, respectively. The minimum thickness measured by the RTVue was similar to that of Pentacam. CONCLUSIONS The RTVue is a rapid and reliable noncontact means of measuring CCT; however, the characteristics of CCT measured by RTVue must be understood when comparing the CCT obtained by the Pentacam or USP. FINANCIAL DISCLOSURE(S) The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Comparison of corneal thickness after the instillation of topical anesthetics: proparacaine versus oxybuprocaine.

To compare changes in human corneal thickness after the instillation of proparacaine with those after oxybuprocaine instillation with time over a period of 10 minutes. Methods: Eighteen healthy young participants were recruited. Proparacaine was used in the right eye and oxybuprocaine in the left. Right and left baseline corneal thicknesses were measured every 30 seconds for 10 minutes using a noncontact specular microscope by 1 observer. Baseline corneal thickness was defined as the average of all values taken over 10 minutes. Changes in corneal thickness were measured every 20 seconds for 10 minutes after the administration of 1 drop of 0.5% proparacaine onto the right cornea and 1 drop of 0.4% oxybuprocaine onto the left cornea. Results: Mean baseline right cornea thickness was 531 ± 45 μm, and that of the left cornea was 531 ± 42 μm. The corneal thickness after proparacaine increased by 8.6 μm (∼4.5-12.6 μm, 95% CI) and then returned to baseline within 80 seconds. Corneal thickness after applying oxybuprocaine increased by 7.7 μm (3.6-11.2 μm, 95% CI) and then returned to baseline within 80 seconds. There was a second transient increase about 5 minutes later after proparacaine instillation but no additional transient increase after oxybuprocaine instillation. Conclusion: Oxybuprocaine is similar to proparacaine in terms of the severity of its effect on corneal thickness. Corneal thickness instability may occur for 5 minutes after proparacaine administration. Changes in corneal thickness after topical anesthetic instillation should be considered when performing measurements for refractive surgery or central corneal thickness in glaucoma patients.

Analysis of Tear Cytokines and Clinical Correlations in Sjögren Syndrome Dry Eye Patients and Non–Sjögren Syndrome Dry Eye Patients

PURPOSE To compare concentrations of tear cytokines in 3 groups composed of Sjögren syndrome (SS) dry eye, non-Sjögren syndrome (non-SS) dry eye, and normal subjects. Correlations between ocular surface parameters and tear cytokines were also investigated. DESIGN Prospective cross-sectional study. METHODS SS dry eye patients (n = 24; 40 eyes) were diagnosed with primary SS according to the criteria set by the American-European Consensus Group. Non-SS dry eye patients (n = 25; 40 eyes) and normal subjects (n = 21; 35 eyes) were also enrolled. Tear concentrations of interleukin (IL)-17, IL-6, IL-10, IL-4, IL-2, interferon γ (IFN-γ), and tumor necrosis factor α (TNF-α) were measured by a multiplex immunobead assay. Ocular Surface Disease Index (OSDI), tear film breakup time (TBUT), Schirmer I test, and fluorescein staining scores were obtained from dry eye patients. RESULTS All cytokine levels except for IL-2 were highest in the SS group, followed by non-SS dry eye group and control subjects. Concentrations of IL-17, TNF-α, and IL-6 were significantly different among the 3 groups (IL-17: SS > control P < .001, non-SS > control P = .042, SS > non-SS P < .001; TNF-α: SS > control P = .006, non-SS > control P = .034, SS > non-SS P = .029; IL-6: SS > control P = .002, non-SS > control P = .032, SS > non-SS P = .002). IL-17 was significantly correlated with TBUT (R = -0.22, P = .012) and Schirmer I test (R = -0.36, P = .027) scores in the SS group. IL-6 was significantly correlated only with TBUT (R = -0.38, P = .02) in the non-SS group. CONCLUSIONS Differences in tear cytokine levels and correlation patterns between SS dry eye and non-SS dry eye patients suggest the involvement of different inflammatory processes as causes of dry eye syndrome.

Evaluation of Dry Eye and Meibomian Gland Dysfunction After Cataract Surgery

PURPOSE To evaluate dry eye and meibomian gland dysfunction after cataract surgery. DESIGN Prospective observational case series. METHODS We studied 58 eyes of 48 patients who underwent phacoemulsification and evaluated them preoperatively and at 1 month and 3 months postoperatively. Ocular symptom scores, lid margin abnormalities, superficial punctate keratopathies (SPKs), tear film break-up time (TBUT), Schirmer test, lower tear meniscus height, depth, and area using Fourier domain optical coherence tomography, meibum expressibility and images of the meibomian glands using meibography were measured. RESULTS The ocular symptom scores were worse at 1 month and 3 months postoperatively (P < 0.001 and P < 0.001, respectively). Lid margin abnormalities were significantly increased (P < 0.001 and P < 0.001, respectively) and TBUT decreased postoperatively (P < 0.001 and P < 0.001, respectively). Meibum expressibility decreased at 3 months postoperatively (P = 0.016); however, meibography score, SPK, lower tear meniscus height, depth and area and the Schirmer test did not change significantly postoperatively (all P values >0.05). CONCLUSION Meibomian gland function may be altered without accompanying structural changes after cataract surgery.

Reliability of RTVue, Visante, and Slit-Lamp Adapted Ultrasonic Pachymetry for Central Corneal Thickness Measurement

Purpose To evaluate reliability of Fourier-domain optical coherence tomography (OCT) (RTVue), time-domain OCT (Visante), and slit-lamp adapted ultrasonic pachymetry (SL-US) in the measurement of central corneal thickness (CCT). Materials and Methods Thirty healthy volunteers visited our clinic 3 times and fifty eyes were measured by one physician. RTVue and Visante were randomly performed, and then SL-US, in which the ultrasound probe was inserted into the Goldmann tonometry mount, was done. During the second visit, each measurement was repeated 3 times. Measurements on the second visit were averaged, and agreement among the instruments was investigated with Bland-Altman plots. Results RTVue showed smaller repeatability coefficient than Visante and SL-US (4.7, 8.3, and 7.7 µm, respectively). Intersession reproducibility of RTVue and Visante was worse than their repeatability. CCT of RTVue was estimated to be maximally different by 11.8 µm from CCT of Visante and 8.8 µm from CCT of SL-US. The repeatability coefficient of SL-US was 7.7 µm and its reproducibility was similar to the repeatability. Conclusion CCT measured by RTVue showed good reliability and generally agreed with Visante and SL-US. SL-US was as reliable as triple touching conventional US even with a single touch on the cornea.

Standard Enucleation with Aluminium Oxide Implant (Bioceramic) Covered with Patient's Sclera

Purpose. We describe in our study a modified standard enucleation, using sclera harvested from the enucleated eye to cover the prosthesis in order to insert a large porous implant and to reduce postoperative complication rates in a phthisis globe. Methods. We perform initially a standard enucleation. The porous implant (Bioceramic) is then covered only partially by the patients sclera. The implant is inserted in the posterior Tenons space with the scleral covering looking at front. All patients were followed at least for twelve months (average followup 16 months). Results. We performed nineteen primary procedures (19 patients, 19 eyes, x M; x F) and secondary, to fill the orbital cavity in patients already operated by standard evisceration (7 patients, 7 eyes). There were no cases of implant extrusion. The orbital volume was well reintegrated. Conclusion. Our procedure was safe and effective. All patients had a good cosmetic result after final prosthetic fitting and we also achieved good prothesis mobility.

Clinical outcomes of individualized botulinum neurotoxin type A injection techniques in patients with essential blepharospasm.

Purpose To assess the clinical outcomes following botulinum neurotoxin type A (BoNT-A) treatment with an individualized injection technique based on the types of spasms and to compare the results of the individualized injection technique with those of the conventional injection technique in the same patients. Methods From November 2011 to July 2013, 77 BoNT-A injections were performed in 38 patients. Eighteen patients were treated with conventional BoNT-A injections before 2011, and 20 patients were referred to our hospital for unsatisfactory results after a conventional injection technique. We classified the patients by spasm-dominant sites: the lateral orbital area, representing the orbital orbicularis-dominant group (ODG); the glabella, representing the corrugator-dominant group (CDG); and the ptosis, representing the palpebral part of the orbicularis-dominant group (PDG). We increased the injection dose into the spasm-dominant sites of the blepharospasm groups. We assessed subjective symptom scores (functional disability score, FDS) after treatment. Results This study included 38 patients (26 women, 12 men; mean age, 60.6 ± 10.9 years). There were 21 patients in the ODG, 10 patients in the CDG, and 7 patients in the PDG. Mean ages were 59.7 ± 12.6, 59.8 ± 8.5, and 66.8 ± 9.0 years, and mean BoNT-A injection dose was 38.8 ± 11.2, 38.8 ± 11.2, and 38.8 ± 10.8 U in each group, respectively (p = 0.44, 0.82 Kruskal-Wallis test). Mean FDS after injection was 1.7 ± 0.7 in the ODG, 1.4 ± 0.8 in the CDG, and 1.2 ± 0.3 in the PDG. There were significant differences in reading and job scale among the three groups. In a comparison between the conventional and individualized injection techniques, there was a significant improvement in mean FDS and in the reading scale in the PDG with the individualized injection technique. The success rate was 92.1% in the conventional injection group and 94.1% in the individualized injection group. Conclusions The individualized injection technique of BoNT-A according to the spasm-dominant site is an effective and safe treatment method for essential blepharospasm patients.

Comparison of surgically induced astigmatism following iris-claw PIOL insertion with scleral, limbal, or corneal incisions.

PURPOSE To compare surgically induced astigmatism (SIA) based on incision site and evaluate the clinical results and astigmatic stability of iris-claw phakic intraocular lens (Artisan lens; Ophtec BV, Groningen, Netherlands) implantation. METHODS Eighty-five eyes of 53 patients with myopia who underwent Artisan lens implantation with a 6.2-mm incision and follow-up of 6 months were retrospectively observed. SIA was assessed using keratometric astigmatism at 6 months postoperatively for the incision sites of the sclera, limbus, and cornea, and the efficacy, safety, predictability, and astigmatic stability were also calculated. RESULTS SIA obtained using Naesers polar method (KP[90]SIA) was -0.48 ± 0.35 for scleral incisions, -0.99 ± 0.35 for limbal incisions, and -1.14 ± 0.54 for corneal incisions. Corresponding net astigmatism values, as calculated with KP(90)SIA and KP(135)SIA, were 0.70 ± 0.48 (177°), 1.04 ± 0.37 (175°), and 1.21 ± 0.57 (1°), respectively, with SIA increasing the nearer the incision was to the cornea center. Six months after surgery, the efficacy index was 1.03 and the safety index was 1.08. Ninety-eight percent of patients were within 1.50 diopters of attempted refraction. CONCLUSIONS The values of SIA after Artisan lens insertion showed significant differences among three incision locations, despite the absence of significant differences in preoperative steep corneal axis astigmatism values at the incision locations. It would be applicable for refractive surgery in the aspect of minimizing astigmatism after surgery.

Analgesic effect of preoperative topical nonsteroidal antiinflammatory drugs on postoperative pain after laser-assisted subepithelial keratectomy.

Purpose To assess the effect of preoperative topical nonsteroidal antiinflammatory drugs (NSAIDs) on postoperative pain after laser‐assisted subepithelial keratectomy (LASEK) and to investigate their mechanism. Setting Severance Eye Hospital and Saeyan Eye Clinic, Seoul, South Korea. Design Prospective randomized clinical trial. Methods Participants in 2 related studies were assessed. Study 1 comprised patients scheduled for bilateral LASEK (Group 1) who were randomized to receive an NSAID in 1 eye and a placebo in the fellow eye 30, 20, and 10 minutes before LASEK. Postoperative pain, glare, tearing, and irritation were assessed using a visual analog scale. Study 2 comprised healthy subjects (Group 2) who were randomly divided into subgroups. The participants in these subgroups were randomized to receive ketorolac tromethamine 0.5% in 1 eye and placebo (ofloxacin 0.3%) in the fellow eye (Group 2A), proparacaine hydrochloride 0.5% in 1 eye and placebo in the fellow eye (Group 2B), or ketorolac tromethamine 0.5% in 1 eye and placebo in the fellow eye, followed 10 minutes later by 1 drop of proparacaine hydrochloride 0.5% in both eyes (Group 2C). In all 3 groups, corneal sensitivity was measured after 1, 2, and 6 hours. Results The mean postoperative pain score in the NSAID‐pretreated eye was statistically significantly lower than in the placebo‐pretreated eye 6, 12, and 24 hours postoperatively (P < .05). The mean corneal sensitivity was statistically significantly lower in the NSAID‐treated eye than in the placebo‐treated eye at 1 and 2 hours in Groups 2A and 2C (P < .05). Conclusion Preoperative administration of topical NSAIDs before LASEK effectively reduces postoperative pain. Financial Disclosure No author has a financial or proprietary interest in any material or method mentioned.

Comparison of analgesic effect of preoperative topical diclofenac and ketorolac on postoperative pain after photorefractive keratectomy

Purpose To investigate changes in the pain‐suppressing potency of 2 preoperatively applied topical nonsteroidal antiinflammatory drugs (NSAIDs) after photorefractive keratectomy (PRK) using a time‐serial pain‐scoring system. Setting Saeyan Eye Center, Seoul, South Korea. Design Comparative case series. Methods Ninety‐four patients were randomly assigned to 2 groups: ketorolac group (ketorolac 0.5% in 1 eye and ofloxacin 0.3% in the other eye) and diclofenac group (diclofenac 0.1% in 1 eye and ofloxacin 0.3% in the other eye). One drop of each ophthalmic drug was applied 3 times to each eye 30 minutes before PRK. No other NSAID or steroid was prescribed until 4 days after PRK. The patients were asked to score the postoperative pain in each eye with a visual analog scale at 6, 18, 24, 36, 48, 72, and 96 hours. Results The natural peak of pain was located between 24 and 36 hours. Initially, the degree of pain reduction was constant for both NSAIDs; it dropped after 24 hours and 36 hours in the ketorolac group and the diclofenac group, respectively. The postoperative time‐serial pattern of the pain score changed in the diclofenac group but not in the ketorolac group compared with the pattern in the ofloxacin‐treated eye. The visual outcome was not affected by either NSAID, and significant complications were not noticed for a mean of 7 months. Conclusions The duration and pattern of the action may vary according to types of NSAIDs. Preemptive topical diclofenac 0.1% was a safe and effective method for post‐PRK pain control. Financial Disclosure No author has a financial or proprietary interest in any material or method mentioned.