Management of Complication after Hyperopic Laser-assisted in-situ Keratomileusis

PURPOSE: We present a case of a patient who underwent corneal refractive surgery to improve their corrected visual acuity due to a complication of hyperopic laser-assisted in-situ keratomileusis (LASIK). CASE SUMMARY: The patient complained of decreased vision after hyperopic LASIK surgery 12 years prior. The corrected distance visual acuity (CDVA) was 20/200 in the right eye and 20/32 in the left, with manifested refractions of +1.25 +2.00 × 90 and -0.25 +2.00 × 80, respectively. The patient had a with-the-rule astigmatism. The values of corneal and total spherical aberration, which can be determined as coefficients of the Zernike polynomials, were respectively -1.027 µm and -0.773 µm in the right eye and -0.965 µm and -0.881 µm in the left eye. Slit lamp biomicroscopy revealed no remarkable findings. We performed surface ablation surgery to flatten the central cornea of the patient's right eye. At 12 months after surgery, the CDVA of the patient's right eye was 20/30 and the negative corneal spherical aberration was reduced. CONCLUSIONS: Corneal refractive surgery to reduce negative corneal spherical aberration by flattening the central cornea is one of possible treatment options for the reduced corrected distance visual acuity after hyperopic LASIK.

Comparison of Intracorneal Inlay for Presbyopia Correction: Hydrogel and Small-Aperture Inlays with a Six- Months Follow-Up

PURPOSE: To study the safety and efficacy of corneal reshaping and small-aperture inlays and compare the clinical results. METHODS: From February 2014 to November 2014, 22 corneal reshaping inlays were inserted at Asan Medical Center and from October 2012 to March 2013, 26 small-aperture inlay surgeries were performed: 6 eyes at Asan Medical Center and 20 eyes at Samsung Medical Center. The preoperative and postoperative parameters were reviewed retrospectively and included monocular uncorrected distance visual acuity (UDVA; log MAR), uncorrected near visual acuity (UNVA; log MAR), refraction and corneal curvature based on automated refractor keratometry, reading distance and patient satisfaction. RESULTS: In the hydrogel inlay group, preoperative mean monocular UNVA was 0.83 +/- 0.05 and monocular UDVA 0.07 +/- 0.03. At 6 months, mean monocular UNVA was 0.23 +/- 0.05 and UDVA 0.05 +/- 0.02. The most preferred mean reading distance in the hydrogel inlay group was 39.38 +/- 3.18 cm. In the small-aperture inlay group, preoperative mean monocular UNVA was 0.4 +/- 0.06 and monocular uncorrected visual acuity 0.27 +/- 0.04. At 6 months, mean monocular UNVA was 0.11 +/- 0.02 and UDVA 0.09 +/- 0.05 and the most preferred mean reading distance was 44.23 +/- 5.17 cm. Although 85% of patients in the corneal reshaping inlay group were satisfied or very satisfied, only 20% of patients in the small-aperture inlay group were satisfied. CONCLUSIONS: Both inlays are considered good options for correcting presbyopia. However, postoperative satisfaction score was higher and less glare symptoms were reported in the hydrogel inlay group.

Comparison of Clinical Outcomes after Various Techniques of Intraocular Lens Dislocation Correction

PURPOSE: To compare clinical outcomes of various surgical methods of intraocular lens dislocation correction surgery. METHODS: We retrospectively analyzed the medical records of patients who underwent intraocular lens dislocation correction surgery with and without vitrectomy by two seasoned surgeons, and compared postoperative best corrected visual acuity and spherical equivalent. Clinical outcomes of secondary intraocular lens insertion after primary intraocular lens removal and primary intraocular lens reposition were compared among the cases without vitrectomy. RESULTS: Dislocated intraocular lens correction without vitrectomy showed better postoperative visual acuity compared to procedures with vitrectomy (0.35 +/- 0.37 vs. 0.54 +/- 0.18; t-test, p = 0.001), but there were no significant differences in spherical equivalent (1.30 +/- 1.10 vs. 1.80 +/- 1.57; p = 0.24) between cases with and without vitrectomy. In comparing primary intraocular lens reposition and secondary intraocular lens insertion among the cases without vitrectomy, the outcomes did not show significant differences in best corrected visual acuity (0.28 +/- 0.40 vs. 0.40 +/- 0.37; p = 0.38) or spherical equivalent (1.66 +/- 1.43 vs. 1.07 +/- 0.79; p = 0.19). In comparing secondary intraocular lens insertion into the capsular bag and fixation to the sclera, iris and iris sulcus, the outcomes did not show significant differences in best corrected visual acuity (p = 0.49) or spherical equivalent (p = 0.33). CONCLUSIONS: The various intraocular lens correction methods examined did not show clinically significant differences in best corrected visual acuity and spherical equivalent when performed by experienced surgeons, except for better postoperative best corrected visual acuity in cases without vitrectomy compared to cases with vitrectomy.

Clinical Characteristics of Glaucomatous Subjects Treated with Refractive Corneal Ablation Surgery

PURPOSE: To evaluate the clinical characteristics of newly diagnosed glaucomatous subjects who had a history of refractive corneal ablation surgery (RCAS). METHODS: Sixty-eight glaucomatous subjects who had a history of RCAS and 68 age- and visual field (VF) mean deviation-matched glaucomatous subjects with no history of RCAS were included. Intraocular pressure (IOP), central corneal thickness (CCT), VF, and retinal nerve fiber layer thickness determined by optical coherence tomography were assessed. Parameters were compared between patients with and without a history of RCAS. Between-eye comparisons in the same participant (more advanced vs. less-advanced eye, in terms of glaucoma severity) were performed in the RCAS group. RESULTS: With similar levels of glaucoma severity, those with a history of RCAS showed significantly lower baseline IOP and a thinner CCT than the eyes of individuals without a RCAS history (13.6 vs. 18.7 mmHg, 490.5 vs. 551.7 micrometer, all p < 0.001). However, the extent of IOP reduction after anti-glaucoma medication did not significantly differ between the two groups (17% vs. 24.3%, p = 0.144). In the between-eye comparisons of individual participants in the RCAS group, the more advanced eyes were more myopic than the less-advanced eyes (-1.84 vs. -0.58 diopter, p = 0.003). CONCLUSIONS: Eyes with a history of RCAS showed a similar level of IOP reduction as eyes without such a history after anti-glaucoma medication. Our finding that the more advanced eyes were more myopic than the less-advanced eyes in the same participant may suggest an association between glaucoma severity and myopic regression.

Clinical Characteristics of Glaucomatous Subjects Treated with Refractive Corneal Ablation Surgery

PURPOSE: To evaluate the clinical characteristics of newly diagnosed glaucomatous subjects who had a history of refractive corneal ablation surgery (RCAS). METHODS: Sixty-eight glaucomatous subjects who had a history of RCAS and 68 age- and visual field (VF) mean deviation-matched glaucomatous subjects with no history of RCAS were included. Intraocular pressure (IOP), central corneal thickness (CCT), VF, and retinal nerve fiber layer thickness determined by optical coherence tomography were assessed. Parameters were compared between patients with and without a history of RCAS. Between-eye comparisons in the same participant (more advanced vs. less-advanced eye, in terms of glaucoma severity) were performed in the RCAS group. RESULTS: With similar levels of glaucoma severity, those with a history of RCAS showed significantly lower baseline IOP and a thinner CCT than the eyes of individuals without a RCAS history (13.6 vs. 18.7 mmHg, 490.5 vs. 551.7 micrometer, all p < 0.001). However, the extent of IOP reduction after anti-glaucoma medication did not significantly differ between the two groups (17% vs. 24.3%, p = 0.144). In the between-eye comparisons of individual participants in the RCAS group, the more advanced eyes were more myopic than the less-advanced eyes (-1.84 vs. -0.58 diopter, p = 0.003). CONCLUSIONS: Eyes with a history of RCAS showed a similar level of IOP reduction as eyes without such a history after anti-glaucoma medication. Our finding that the more advanced eyes were more myopic than the less-advanced eyes in the same participant may suggest an association between glaucoma severity and myopic regression.

Comparison of Surgical Parameters and Outcomes According to the Phacoemulsification Technique

PURPOSE: To compare intraoperative parameters and postoperative results between divide-and-conquer and multiple phaco-chop technique. METHODS: Two different techniques were performed by one operator on the patients with bilateral cataract. One eye was phacoemulsified by divide-and-conquer technique (D eye), and the other was performed by multiple phaco-chop technique (M eye). Changes of central corneal thickness during the operation, total phaco-time and phaco-energy were measured. RESULTS: Total 29 patients were included. The change of central corneal thickness were 8.4 +/- 11.8 microm in D eye and 11.5 +/- 16.7 microm in M eye, which showed no significant difference (p = 0.350) and total phaco-time were 70.1 +/- 32.9 seconds in D eye and 71.1 +/- 55.0 seconds in M eye, which also showed no significant difference (p = 0.689). However, phaco-energy were 12.4 +/- 8.3 power x s in D eye and 8.4 +/- 9.9 power x s in M eye, and this result showed significantly larger energy when using divide-and-conquer technique (p < 0.001). CONCLUSIONS: There was no significant difference in change of central corneal thickness and phaco-time between two techniques, divide-and-conquer and multiple phaco-chop technique. However, significantly smaller phaco energy was used by multiple phaco-chop technique compared with divide-and-conquer technique.

Clinical Outcome of in-the-Bag Single-Piece Aspheric Intraocular Lens Implantation after Microincision Cataract Surgery

PURPOSE: To evaluate the stability and optical performance of the newly developed single-piece aspheric intraocular lens (IOL) by comparing the clinical outcome of the aspheric IOL with the new optic profile design (HOYA iSert, HOYA iMics) and the aspheric IOL (Akreos MI60), which has been proven effective and safe. METHODS: iSert, iMics, and MI60 were inserted into 55 eyes, 60 eyes, and 50 eyes, respectively, after microincision phacoemulsification cataract surgery. Best corrected visual acuity (BCVA), refraction in spherical equivalent, anterior chamber depth (ACD), total higher order aberration (HOA), contrast sensitivity, and surgically induced astigmatism (SIA) were measured and each IOL was evaluated on the functional stability, anterior-posterior stability, centration in the capsular bag, and quality of vision. RESULTS: No statistical differences in preoperative and postoperative BCVA among the 3 IOL groups were observed, however, MI60 showed significant myopic shift postoperatively. Anterior-posterior stability assessed with postoperative change in refractive error and ACD was slightly lower in the MI60 group. In terms of vision quality, while total aberration, total HOA, coma aberration, and contrast sensitivity for the 3 IOLs were not different significantly, spherical aberration of the MI60 group was higher than the other groups at 6 months postoperative. SIA was significantly increased in eyes implanted with iSert than in eyes with iMics or MI60 at 1 month postoperatively, however, the differences were no longer evident after 3 months postoperatively. CONCLUSIONS: The new aspheric IOLs, iSert and iMics, showed good stability and visual outcome equal to MI60 at the 6-month postoperative follow-up.

Clinical Outcomes after Combined Ahmed Glaucoma Valve Implantation and Penetrating Keratoplasty or Pars Plana Vitrectomy

PURPOSE: To evaluate whether a combination of penetrating keratoplasty (PKP) or pars plana vitrectomy (PPV) and Ahmed glaucoma valve (AGV) implantation affords a level of success similar to that of AGV implantation alone. METHODS: Eighteen eyes underwent simultaneous PPV and AGV, 14 eyes with PKP and AGV and 30 eyes with AGV implantation alone were evaluated. Success was defined as attainment of an intraocular pressure (IOP) >5 and <22 mmHg, with or without use of anti-glaucoma medication. Kaplan-Meier survival analysis was performed to compare cumulative survival between the combined surgery groups and the AGV implantation-alone group. Cox proportional hazard regression analysis was conducted to identify factors predictive of success in each of the three groups. RESULTS: Mean (+/-standard deviation) preoperative IOP was 30.2 +/- 10.2 mmHg in the PKP + AGV, 35.2 +/- 9.8 mmHg in the PPV + AGV, and 36.2 +/- 10.1 mmHg in the AGV implantation-alone group. The cumulative success rate at 18 months was 66.9%, 73.2%, and 70.8% in the three groups, respectively. Neither combined surgery group differed significantly in terms of cumulative success rate compared with the AGV implantation-alone group (p = 0.556, p = 0.487, respectively). The mean number of preoperative anti-glaucoma medications prescribed was significantly associated with success in the PKP + AGV implantation group (hazard ratio, 2.942; p = 0.024). CONCLUSIONS: Either PKP or PPV performed in conjunction with AGV implantation afforded similar success rates compared to patients treated with AGV implantation alone. Therefore, in patients with refractory glaucoma who have underlying corneal or retinal pathology requiring treatment with PKP or PPV, AGV implantation can be performed simultaneously.

Estimation of Corneal Spherical Aberration from Topography

PURPOSE: To formulate an equation to estimate corneal spherical aberration using Orbscan (Bausch & Lomb Surgical, Rochester, NY, USA) parameters. METHODS: The study was carried out retrospectively. The participants were 76 eyes of 76 senile cataract patients with the mean age of 57.37 +/- 17.63 years. Both Orbscan and KR-1W (Topcon Corp, Tokyo, Japan) were taken as preoperative examinations. Correlation analysis between various parameters from Orbscan and corneal spherical aberrations for a 6 mm pupil by KR-1W was performed. And multivariable linear regression was performed with the significantly correlated Orbscan parameters from the correlation analysis. RESULTS: The mean corneal spherical aberration from KR-1W system was 0.25 +/- 0.08 microm. As a result of the multivariable linear regression, we could generate following equations. If the Q-value was available, estimated corneal spherical aberration = 0.389 x Q-value + (0.022 x Axial power 3 mm) - 0.633 (R2 = 0.436). If the Q-value was not available, estimated corneal spherical aberration = 0.184 x (Mean power 5 mm - Mean power 3 mm) + (0.02 x Axial power 3 mm) - 0.563 (R2 = 0.429). By using the equations, 93.4-94.7% of subjects were in the error range of 0.10 microm. CONCLUSIONS: Even when equipped with Orbscan only, an appropriate aspheric intraocular lens can be selected using the estimated corneal apherical aberration by the equations.

Clinical Outcomes of Aspheric 1-Piece (Tecnis(R) ZCB00) and 3-Piece (Tecnis(R) ZA9003) Aspheric Intraocular Lens for 12 Months

PURPOSE: To evaluate the postoperative outcome of Tecnis(R) ZCB00 1-Piece acrylic intraocular lens (IOL), the new single piece, aspheric IOL until 12 months. METHODS: Sixty eyes undergone cataract surgery using two different IOLs; The Tecnis(R) ZCB00 1-Piece Acrylic IOL (30 eyes) and the Tecnis(R) ZA9003 3-Piece Acrylic IOL (30 eyes). Cataract surgery was performed in the same period. All complicated cases were excluded. Best corrected visual acuity (BCVA), refractive error, photopic and mesopic contrast sensitivity, total high order aberration, spherical aberration and anterior chamber depth were measured preoperatively and at 1, 6 and 12 months after surgery. RESULTS: There were no statistically significant differences between two groups in BCVA, refractive error, total high order aberration and spherical aberration all the time after surgery. Both groups have negative ocular spherical aberration until 12 months after surgery. 1-piece and 3-piece groups had different tendency in axial movement. But there were no statistically significant differences in anterior chamber depth measured at 1 week, 1, 6 and 12 months after surgery. There was no statistically significant difference in contrast sensitivity at 1, 6 and 12 months after surgery. CONCLUSIONS: The Tecnis(R) ZCB00 1-Piece acrylic intraocular lens (IOL) showed comparable clinical outcomes to the Tecnis(R) ZA9003 3-Piece acrylic intraocular lens (IOL) until 12 months after cataract surgery. 1-piece and 3-piece IOL group had different tendency in axial movement. However, refraction remained stable during 12 months after surgery. Mostly, both IOL groups had negative ocular spherical aberration during whole follow-up period.

Comparison of Flap Thickness Measured with Ultrasound Subtraction Method, Direct Method, and Optical Coherence Tomography

PURPOSE: To compare the flap thicknesses measured with the ultrasound (US) subtraction method, the direct method, and optical coherence tomography (OCT) in femtosecond laser-assisted LASIK eyes. METHODS: The present study included 65 eyes of 37 patients who underwent femtosecond laser-assisted LASIK surgery. Flap thickness was measured intraoperatively using the direct and subtraction methods with US pachymetry and postoperatively using anterior segment OCT. Flap thickness measurements were compared among the three methods. RESULTS: There was no significant difference between the flap thickness measured using the US subtraction method and OCT (p = 0.511). The flap thickness values obtained by these two different methods also correlated well with each other (gamma = 0.820, p < 0.001). However, flap thickness measured using the US direct method was significantly different (p < 0.001) with a low agreement value compared to the other two methods. Furthermore, the US direct method showed a lower measurement success rate compared to the US subtraction method (54% vs. 95%). CONCLUSIONS: Flap thickness measured using the US subtraction method and OCT showed different values compared to that measured using the US direct method. Because of the lower measurement success rate and agreement value, the US direct method is not capable of being used in substitute for the US subtraction method.

One-year Outcome of Monocular Implant of Aspheric Multifocal IOL

PURPOSE: To evaluate near and far visual acuity, subjective visual symptoms, and patient satisfaction with a monocular implant of aspheric multifocal IOL (AMO Tecnis ZM900(R)). METHODS: Thirty eyes of 30 patients received phacoemulsifications and monocular implantation of Tecnis ZM900 IOL. The main outcome measures at postoperative 1 week, 1 month, 3 months, and 1 year were uncorrected and corrected near and distant visual acuity, refractory errors, contrast sensitivity, subjective visual symptoms (glare and halo), spectacle independency, and satisfaction. RESULTS: At a 3 month postoperative visit, the mean uncorrected near and distant visual acuities were 0.29+/-0.17 (logMAR) and 0.16+/-0.12 (logMAR),respectively. At 1 year, the mean uncorrected near and distant visual acuities were 0.25+/-0.17 (logMAR) and 0.11+/-0.08 (logMAR). Glare and halo decreased, and contrast sensitivity increased upon 1-year follow-up after monocular implantation of ZM900. Most patients (87%) were satisfied with their visual outcome. CONCLUSIONS: Monocular implantation of multifocal IOL Tecnis ZM900 shows stable surgical outcomes with a high satisfaction rate and enables a high rate of spectacle independency. Postoperative glare and halo, youth, and residual refractive error could be risk factors for dissatisfaction with monocular implantation of multifocal IOL Tecnis ZM900. Proper patient selection can lead to satisfying outcomes.

Changes in Anterior Chamber Depth and Angle After Phacoemulsification measured by Anterior Segment Optical Coherence Tomography

PURPOSE: To evaluate changes in anterior chamber depth (ACD) and angle after phacoemulsification and intraocular lens implantation using anterior segment optical coherence tomography (AS-OCT). METHODS: Seventy-eight eyes of 69 patients had uneventful phacoemulsification and IOL implantation using a clear corneal incision. Anterior segment OCT images of nasal and temporal angle quadrants were obtained before and at one month after surgery. The angle-referenced (ACD1), pupil-referenced (ACD2), lens-referenced (ACD3) ACDs, crystalline lens rise (CLR), nasal and temporal iridocorneal angles, angle opening distance at 500 micrometer (AOD500), and trabecular iris surface area at 750 micrometer (TISA750) were measured. Preoperative and postoperative measurements were compared using paired sample t-tests. RESULTS: The mean ACD1 was 3.19+/-0.24 mm preoperatively and 3.22+/-0.21 mm at one month postoperatively (P=0.21); ACD2 was 2.99+/-0.40 mm preoperatively and 3.56+/-0.28 mm at one month postoperatively (P<0.05); ACD3 was 2.75+/-0.41 mm preoperatively and 4.00+/-0.27 mm at one month postoperatively (P<0.05). The mean iridocorneal angles, AOD500, and TISA750 for both nasal and temporal sides increased significantly at the postoperative examinations (P<0.05). CONCLUSIONS: Changes in anterior chamber angle after cataract surgery can be objectively quantified by anterior segment OCT. Deepening of the anterior chamber and widening of the nasal and temporal angles after cataract extraction were shown on AS-OCT.

Utility of the Anterior Segment Optical Coherence Tomography for Measurements of Central Corneal Thickness

PURPOSE: To demonstrate the capability of anterior segment optical coherence tomography (OCT), to evaluate central corneal thickness (CCT) and to compare the results with those by Orbscan II and standard ultrasound (US) pachymetry. METHODS: One examiner measured the CCT of 44 normal eyes of 22 subjects using anterior OCT, Orbscan II, and US pachymetry. Non-contact measurements by anterior segment OCT and Orbscan II were performed first, followed by contact measurements using US pachymetry. Three consecutive measurements were taken with each method and the mean values and correlations were analyzed. RESULTS: The mean value of the CCT was 531.45+/-32.90 micrometer with anterior OCT, 537.11+/-32.21 micrometer with Orbscan II, and 548.18+/-34.17 micrometer with US pachymetry. There was no statistically significant difference among the values obtained by the 3 instruments (P>0.05). CCT measurements by anterior segment OCT were highly correlated with Orbscan II and US pachymetry (P<0.001) measurements. CONCLUSION: CCT measurements by anterior segment OCT are highly correlated with Orbscan II or US pachymetry measurements. Using non-contact anterior segment OCT, a closer examination of the anterior segment including the cornea is possible. The measurement of the CCT using anterior segment OCT is applicable because result values are similar to measurements by Orbscan II or US pachymetry.

Clinical Comparison of Laser Ray Tracing Aberrometer and Shack-Hartmann Aberrometer

PURPOSE: To compare ocular aberrations measured with a laser ray tracing aberrometer (iTrace(R), Tracey technology) or a Shack-Hartmann aberrometer (Zywave(TM), Bausch & Lomb). METHODS: A total of 68 eyes were included in this study. After manifest refraction (MR) and pupil dilation, aberrations and phoroptor predicted refraction (PPR) were measured with the Zywave(TM) and iTrace(R) devices. The study group was subdivided into a more myopic group (-4.33 D). The root mean square (RMS) errors of the total high order, spherical, coma and 3rd~5th order aberrations were compared. RESULTS: The mean and SE of MR was -4.33+/-2.03 diopter (D), and that of the PPR was -4.20+/-2.13 D in iTrace(R) and -4.42+/-2.23 D in Zywave(TM). A paired-t test of the PPR and MR indicated that they were not statistically different. Zernike coefficients were expressed in the opposite sign in the 2nd and 4th order. The coma and spherical aberrations were larger in Zywave(TM). In a scattergram of each Zernike coefficient, the coefficient of determination (R2) was very low with higher order aberrations, with an exception for coma and spherical aberrations. The correlation of RMS error was greater in the less myopic group. CONCLUSIONS: Taking PPR values as a good reference of MR was a reliable method. For the HOA, only coma and spherical aberrations showed good correlations between Zywave(TM) and iTrace(R), and the correlations for HOA were decreased for the high myopic eyes.

Epidemiologic Studies of Keratoplasty in Korea

PURPOSE: To report an epidemiologic study of keratoplasty in which we analyze basic data of corneal transplants and corneal donations in Korea. METHODS: From June 2004 through October 2004, questionnaires were distributed to 25 hospitals. The questionnaires were about the characteristics of patients registered in eye banks for keratoplasty from May 2001 to April 2003, and about the results of keratoplasties performed from May 2002 to April 2003. RESULTS: The leading corneal diseases in patients registered for keratoplasty were infectious keratitis (22.0%), trauma (21.0%), and pseudophakic and aphakic bullous keratopathy (13.8%), in that order. The leading indications in corneal recipients were: trauma (15.5%), pseudophakic and aphakic bullous keratopathy (13.7%), and infectious keratitis (10.7%), in that order. In 233 cases of keratoplasties, penetrating keratoplasty was performed in 229 cases (98.3%) and lamellar keratoplasty was performed in 4 cases (1.7%). The most common combined surgery was cataract extraction. Common causes of graft failure were rejection of donor cornea and infection. Imported donor corneas were used in sixty-one cases (26.2%) among the 233 total keratoplasties. CONCLUSIONS: We constructed an epidemiologic data base of patients registered for keratoplasty, corneal donation, and the results of keratoplasties throughout Korea.

Epidemiologic Studies of Keratoplasty in Korea

PURPOSE: To report an epidemiologic study of keratoplasty in which we analyze basic data of corneal transplants and corneal donations in Korea. METHODS: From June 2004 through October 2004, questionnaires were distributed to 25 hospitals. The questionnaires were about the characteristics of patients registered in eye banks for keratoplasty from May 2001 to April 2003, and about the results of keratoplasties performed from May 2002 to April 2003. RESULTS: The leading corneal diseases in patients registered for keratoplasty were infectious keratitis (22.0%), trauma (21.0%), and pseudophakic and aphakic bullous keratopathy (13.8%), in that order. The leading indications in corneal recipients were: trauma (15.5%), pseudophakic and aphakic bullous keratopathy (13.7%), and infectious keratitis (10.7%), in that order. In 233 cases of keratoplasties, penetrating keratoplasty was performed in 229 cases (98.3%) and lamellar keratoplasty was performed in 4 cases (1.7%). The most common combined surgery was cataract extraction. Common causes of graft failure were rejection of donor cornea and infection. Imported donor corneas were used in sixty-one cases (26.2%) among the 233 total keratoplasties. CONCLUSIONS: We constructed an epidemiologic data base of patients registered for keratoplasty, corneal donation, and the results of keratoplasties throughout Korea.

Chemical Burns of the Cornea Due to Soda Lime Used for Line Marking on the Playground

PURPOSE: The hydrated form of lime used for marking lines on the ground is a corrosive alkali. The harmful effects of lime are well known, and chemical burns of human tissue due to lime have been reported. We report a case of chemical injury of the cornea caused by exposure to lime at a playground. METHODS: A 3-year-old male patient presented with decreased visual acuity after slipping on the playground. His best corrected visual acuity (BCVA) was 20/40 in the right eye (OD), and hand motion in the left eye (OS). On biomicroscopic examination, bilateral corneal opacity and corneal erosion were observed. In the OS, the corneal opacity involved the visual axis and resulted in vision impairment. He was treated with eye drops. RESULTS: After treatment for 3 months, his corrected visual acuity was 20/30 in the OD, and 20/125 in the OS. The corneal opacity was not improved and corneal thinning was observed in the OS. After 1 year, BCVA was 20/25 in the OD, and 20/100 in the OS. CONCLUSIONS: The lime used for marking white lines on the ground can cause opacity and thinning of the cornea. Other, safer methods for line marking should be considered.

Lamellar Keratoplasty and Restoration of Traumatic Dislocation of LASIK Flap Using Human Fibrin Adhesive

PURPOSE: To report two cases of sutureless corneal surgery performed with human fibrin sealant: lamellar keratoplasty and revision of traumatic LASIK flap dislocation. METHODS: In one case, lamellar keratoplasty was performed because of corneal opacity in the anterior stroma, which occurred after herpes simplex keratitis. Free flaps were made in donor and recipient corneas using an Automated Corneal Shaper(TM) (ACS(TM)). After human fibrin sealant was applied to the surface of the recipient's stromal bed, the donor's corneal flap was attached to the bed. The other patient evaluated had partial dislocation of the LASIK flap following trauma. The corneal epithelium covered the lifted and wrinkled corneal flap. The epithelium was removed after applying 20% alcohol. Then, the flap was repositioned and fixed using human fibrin sealant. RESULTS: At postoperative 3 months, clarity and integrity were maintained without serious complications. Visual acuity was improved in both cases. However, an additional procedure was needed in the case of LASIK flap revision because of epithelial ingrowth. CONCLUSIONS: Human fibrin sealant is an effective tool for corneal surgery and is advantageous because it does not require sutures. However, further studies that involve a large number of patients and a longer follow-up period are required to validate its universal use.

Comparison of the Phaco Chop and the Mini Chop Methods in Cataract Surgery

PURPOSE: To compare effective phacoemulsification time (EPT), the severity of corneal swelling and corneal endothelial cell density after cataract surgery between the phaco chop method and the mini chop method. METHODS: Cataract surgery was performed by phaco chop (15 eyes) or by mini chop (13 eyes) method in 28 eyes of 27 patients. The nuclear opacity of cataract grade was more than 5 on LOCS (Lens opacities classification system) III. EPT and the amount of irrigated BSS solution were measured during the operation. Corneal thickness (preoperative, immediate postoperative, postoperative 1 day, 1 week, 1 month, and 3 months) and corneal endothelial cell density (preoperative, postoperative 1month and 3 months) were measured. RESULTS: The EPT of phaco chop group was 5.2 sec and that of mini chop was 1.0 sec (p=0.000). The amount of irrigated BSS was 193.7 ml and 170.4 ml in the phaco chop group and the mini chop group, respectively. The increase in corneal thickness was 3.2% and 0.9% at immediately after surgery (p=0.128), 19.0% and 10.5% at postoperative 1 day (p=0.088), 5.7% and 1.5% at postoperative 1 week (p=0.080), 0% and -1.3% at postoperative 1 month (p=0.717), and -0.4% and -0.6% at postoperative 3 months (p=0.890) in the phaco chop group and the mini chop group, respectively. Corneal endothelial cell density decreased 23.0% in the phaco chop group and 9.4% in the mini chop group at postoperative 1 month (p=0.005) and 22.9%, 12.6%, at 3 months respectively (p=0.036). CONCLUSIONS: The mini chop technique reduced permanent endothelial cell damage in comparison with the phaco chop method and might be more effective in decreasing corneal swelling during the early postoperative period than the phaco chop method.