Suk Kyue Choi

Creation of an extremely thin flap using IntraLase femtosecond laser.

A 43-year-old woman had laser in situ keratomileusis (LASIK) using the IntraLase femtosecond laser (IntraLASIK) to create 110 microm flaps. Despite uneventful flap formation, the flaps in both eyes were extremely thin, making it difficult to lift them. The flap in the right eye resembled an epi-LASIK epithelial flap. It was lifted uneventfully. The flap in the left eye was stretched and torn on lifting, and the procedure was therefore postponed. After 6 months, the IntraLASIK surgical procedure was repeated in the left eye using a thicker and smaller flap than in the first procedure. Despite the improvements associated with using an IntraLase femtosecond laser, thinner-than-intended corneal flaps can occur. Early recognition of such a flap can prevent further complications.

Different epithelial cleavage planes produced by various epikeratomes in epithelial laser in situ keratomileusis

PURPOSE: To determine the anatomic cleavage planes produced by various epikeratomes in epithelial laser in situ keratomileusis (epi‐LASIK). SETTING: Department of Ophthalmology, IIsan Paik Hospital, Goyang, Korea. METHODS: Sixteen eyes (8 patients) were included in this study. Three epikeratomes, the Moria Epi‐K, Centurion SES, and Amadeus II, were used to collect 4 epithelial flaps from 2 patients in the epi‐LASIK procedure. Four epithelial flaps from 2 patients were also obtained by laser‐assisted subepithelial keratectomy (LASEK). Immunohistochemical staining using monoclonal antibodies against integrin ß1, integrin ß4, laminin 5, and collagen type VII was performed. RESULTS: Immunohistochemical staining showed expression of integrin ß1 and integrin ß4 in all epithelial flaps. In epi‐LASIK, the expression of laminin 5 and collagen type VII had a linear or dotted pattern that differed based on the epikeratome used. In the epithelial flaps obtained using LASEK, the expression of laminin 5 and collagen type VII had a dotted pattern. CONCLUSIONS: Each epikeratome yielded reproducible but different cleavage planes of corneal epithelium. The results suggest that further study is needed to elucidate the wound‐healing process after epi‐LASIK because different cleavage planes produced by different epikeratomes may influence the process.

Femtosecond Laser Lamellar Keratoplasty to Aid Visualization for Cataract Surgery

PURPOSE To describe a new surgical technique for a patient with cataract combined with corneal opacity. METHODS This technique, femtosecond laser-assisted cataract surgery, was performed on a patient with a history of corneal opacity in both eyes from childhood. Because the patient had deep stromal corneal opacity, a corneal button 400-mum thick was made for lamellar keratoplasty while cataract surgery was performed simultaneously. RESULTS Lifting of the flap and removal of the corneal button before cataract surgery was successful without any intraoperative complications. CONCLUSIONS Femtosecond laser-assisted cataract surgery is a promising surgical procedure for a cataract patient with stromal corneal opacity.

Treatment of corneal opacity by planned lamellar keratectomy using the femtosecond laser.

Purpose: To report successful vision restoration after lamellar keratectomy using a femtosecond (FS) laser in a patient with superficial corneal opacity that developed after an episode of epidemic keratoconjunctivitis. Methods: A 19-year-old girl with corneal opacity in the left eye was referred to our department for treatment. The opacity was principally located within the superficial anterior cornea. To remove the opacity with minimization of change in the keratometric value, we performed lamellar keratectomy with the aim of creating a 100-μm-thick flap, using an FS laser (IntraLase FS; AMO, Irvine, CA). Results: Postoperatively, corneal opacity was removed and vision improved. Six months after surgery, the corneal surface was stable and smooth, and no corneal haze was observed. The keratometric value measured by corneal topography and manifest refraction showed no hyperopic shift postoperatively. Conclusions: This report indicates that the FS laser may be an effective surgical tool for the treatment of patients with corneal opacity and that hyperopic shift is not of concern.

The effect of femtosecond laser lamellar dissection at various depths on corneal endothelium in the recipient bed of the porcine eye.

BACKGROUND AND OBJECTIVE To evaluate the effect of femtosecond laser lamellar dissection on corneal endothelium ultrastructure and viability. MATERIALS AND METHODS Newly enucleated porcine eyes (N = 32) were used. The eyes were divided into four groups and a 7.5-mm diameter corneal lamellar dissection with the same size side cut at various depths was performed using a 60-kHz femtosecond laser with raster and spiral lamellar pattern. The endothelium was examined using scanning electron microscopy and light microscopy with Alizarin red staining. RESULTS All four groups showed similar corneal endothelial cell morphology and viability at the center of the endothelium regardless of the lamellar cut pattern (P > .05). In groups 2 and 3, linear dotted endothelial cell damage or folding correlating with the side cut was observed. CONCLUSION Using femtosecond lasers for stromal dissection and side cutting was safe for the central endothelium and caused only minimal damage to the peripheral endothelium, regardless of the laser emission pattern.

A novel technique: eccentric lamellar keratolimbal allografting using a femtosecond laser.

Purpose: To report on a patient who received an eccentrically designed lamellar keratolimbal allograft prepared using a femtosecond (FS) laser to preserve peripheral curvature. Methods: A 19-year-old woman, with a pseudopterygium on the left eye resulting from dermoid excision about 11 years earlier, received an eccentric lamellar keratolimbal allograft in a procedure involving FS laser use. Corneal flaps of depths 280 and 400 μm and diameters 6.5 and 6.6 mm were eccentrically created by FS laser treatment of the recipient and donor eyes, respectively, after removal of the pseudopterygium. After amniotic membrane transplantation, the eccentrically designed corneal flap was secured with 10-0 nylon sutures. Results: Corneal flap creation was uneventful. Only minimal suturing was required for lamellar keratoplasty, and no complications occurred. Twelve months after surgery, a stable corneal surface was observed, with minimal scar formation at the graft margin and relatively good graft interface clarity. Conclusion: Eccentric lamellar keratolimbal allografting using an FS laser is an effective and time-saving surgical method to treat peripheral corneal abnormalities featuring corneal opacity.

A new surgical technique: a femtosecond laser-assisted keratolimbal allograft procedure.

Purpose: To evaluate the feasibility of a femtosecond (FS) laser-assisted keratolimbal allograft (KLAL) technique. Design: Interventional case series. Methods: This study included 3 patients with extensive limbal stem cell deficiency. The donor cornea was dissected with an FS laser (IntraLase FS laser, 60 kHz) using a ring procedure, without outer side cutting for the limbal graft, after a penetrated dissection of the donor cornea prior to penetrating keratoplasty (PKP). The depth and width of the ring procedure were adjusted for each individual patient. Further extension to the periphery of the sclerocorneal tissue of the donor graft was performed with a diamond knife. In a case of KLAL alone, the unhealthy limbal tissue of the recipient was removed with the FS laser by the same method employed in donor preparation. One patient underwent KLAL alone, and 2 patients underwent KLAL combined with PKP. The patients were followed up for a maximum of 10 months. Results: Limbal grafts were even and thin, as expected. The case with KLAL alone showed the fastest epithelization of the recipient cornea. The 2 cases of combined KLAL and PKP showed excellent approximation between recipient and donor tissue. The ocular surfaces have been stable for 8 months in case 1 and 10 months in cases 2 and 3. Conclusion: FS laser-assisted KLAL has potential advantages in terms of simplicity and speed as compared with conventional techniques.

IOL Tilt and Decentration

Dear Editor: A cornea with a positive spherical aberration (SA) can be corrected by placement of an intraocular lens (IOL) with a negative SA value. However, the theoretical advantage of a negative SA can be offset by IOL tilt and decentration. Theoretical reports indicate that coma increases with rising IOL tilt and decentration under optical bench conditions. Thus, we analyzed internal higher-order aberrations (HOAs) based on tilt and decentration after cataract surgery and implantation of different aspherical IOLs with negative SA. This prospective study enrolled 32 patients with senile cataracts who underwent phacoemulsification and randomized implantation of AcrySof IQ IOLs (Alcon Laboratories, Fort Worth, TX) in one eye and Tecnis Z9003 IOLs (AMO Inc., Santa Ana, CA) in the other. Patients were evaluated preoperatively and at 1and 2-month follow-up intervals. Uncorrected visual acuity, best-corrected visual acuity (BCVA), manifest refraction, contrast sensitivity under mesopic and photopic conditions, modulation transfer function (MTF), and point-spread function (PSF) were measured 1 and 2 months after surgery. Corneal, internal, and ocular HOAs for 6-mm pupils (up to the 6th order) were measured using a Hartmann-Shack aberrometer (model KR-9000PW; Topcon, Tokyo, Japan) at the 1and 2-month follow-up visits. Intraocular lens decentration and tilt were measured by the anterior segment analysis system (EAS-100 instrument; Nidek Inc., Gamagori, Japan) at the 1and 2-month follow-up visits. There were no statistically significant differences in BVCA, contrast sensitivity, PSF, or MTF between the IQ and Tecnis groups (P 0.05) (Tables 1 and 2; Figs 1 and 2; available at http://aaojournal.org). Internal spherical aberration for the 6-mm pupil was significantly less in the Tecnis group ( 0.268 0.074 m) than in the IQ group ( 0.197 0.058 m) at the 2-month follow-up (P 0.041) (Table 3; available at http://aaojournal.org). IOL decentration and tilting did not differ significantly between the 2 groups or within either group postoperatively (P 0.05) (Table 4; available at http://aaojournal.org). There was no significant correlation between ocular HOA and IOL tilt and decentration. However, there was a significant relationship between aspherical IOL tilt and internal coma aberration after surgery in both groups (IQ group: P 0.029, r 0.387; Tecnis group: P 0.006, r 0.478) at the 2-month follow-up (Figs 3 and 4; available at http://aaojournal.org). Tilted or decentered IOLs with negative SA can induce a higher level of asymmetrical aberration and may consequently impair visual quality. Although several laboratory studies of IOL tilt and decentration have appeared, only 2 clinical studies evaluated the correlation between ocular aberration, and IOL tilt and decentration, after implantation. Our results indicated that there was no significant correlation between ocular HOAs, and aspherical IOL tilt and decentration, but there was a significant relationship between aspherical IOL tilt and internal coma. The correlation between IOL tilt and internal coma in both sets of eyes

The usefulness of the "double-needle" technique for combined cataract extraction and corneal transplantation.

The authors report using double-needle cataract extraction in the course of triple surgery and describe the usefulness of a double-needle technique. Before penetrating preparation of the recipient cornea, two straight double-arm 10-0 Prolene needles (Ethicon, Edinburgh, Scotland) were inserted in parallel on the recipient corneal bed transcorneally immediately anterior to the iris. The use of two needles stabilized the iris plane and offset positive vitreous pressure during triple surgery, continuous curvilinear capsulorrhexis, phacoemulsification, irrigation, and aspiration, allowing the safe implantation of an intraocular lens in the bag in an open-sky state. There were no procedural difficulties and no complications. This simple technique using double needles in triple surgery can be used effectively and may prevent forward movement of the lens-iris diaphragm, anterior capsular tearing, and rapid expulsion of the lens caused by positive vitreous pressure in the open-sky state.

Breakage of the haptic of a single-piece acrylic intraocular lens after transscleral fixation

Editor, I n situations lacking capsular support, ocular surgeons prefer transscleral fixation of foldable intraocular lenses (IOLs). Modifications and improvements in surgical techniques have led to transscleral fixation using single-piece acrylic foldable IOLs with satisfactory clinical results, despite concerns about the tilting and decentring of the IOL (Packer et al. 2002; Taskapili et al. 2007). However, we observed a patient in whom haptic breakage of a single-piece IOL occurred following transscleral fixation, suggesting that single-piece IOLs may not be safe in transscleral fixation. A 53-year-old man was referred to us for aphakia in his right eye. Forty years earlier, he underwent intracapsular cataract extraction in the right eye because of ocular trauma. The preoperative refractive error was +4.0 D (= )1.25 Dcy 180 ) in his right eye, and +0.5 D in his left eye. The best spectacle-corrected visual acuity (BSCVA) was 20 ⁄ 25 in his right eye and 20 ⁄ 20 in his left eye. The mean axial lengths, as measured by ultrasound (Ultrascan Imaging System , Alcon Laboratories, Fort Worth, Texas, USA), were 28.5 mm in the right eye and 23.2 mm in the left eye. IOL transscleral fixation was scheduled in the right eye, using a 7-D aspherical single-piece acrylic foldable IOL (AcrySof IQ ; Alcon Laboratories, Fort Worth, Texas, USA). Because of the relatively high preoperative spherical aberration and coma-like higher-order aberration in the patient’s cornea, we used an aspherically designed single-piece acrylic IOL (AcrySof IQ ), although an aspherical IOL couldn’t compensate astigmatism and coma-like higher-order aberration. We utilized a four-point transscleral fixation technique because it may decrease concerns about postoperative IOL decentration and tilting (Rao et al. 2000; Sewelam 2003). However, on the first postoperative day we found that the transscleral-fixated IOL had become dislocated and that one haptic was broken (Fig. 1A). Scanning electron microscopy (SEM) of the removed IOL was performed to analyse the broken surface. SEM indicated that the cleavage plane of the intravitreally broken haptic was created by a cutting effect. The cut surface of the haptic was likely made by the intermittent cutting force of a sharp material (Fig. 1B,C). Although the reasons for postoperative breakage of the IOL haptic in this patient remain unclear, several factors may be involved, including the surgical technique. The four-point scleral transfixation method seems to induce a relatively strong shearing stress in the haptic, despite the stable position of the IOL. In addition, the mean overall distance between two points, located 4 mm apart from the two haptic margins of a single-piece IOL, was 9.96 mm; meanwhile, the total length of each IOL is 13 mm. This means that the distance from suture to suture was less than the patient’s white-to-white diameter. Therefore, if the suture is positioned in the more proximal part of the haptic, there may be a stronger shearing stress on the suture, consequently resulting in the suture cutting into the sclera (‘cheesewiring’). Breakage may also have been caused by the unusual condition of this patient. Fundus examination showed that axial length, preoperative refraction and dioptre IOL in the right eye were indicative of severe myopia in the phakic state. Furthermore, IOL fluctuation caused by abrupt changes in intraocular pressure during irrigation and aspiration may have increased the pulling strength on the haptic of the IOL and on the suture. Also, excessive vitrectomy or deepening of the anterior chamber by inflation at the end of surgery may promote IOL fluctuation in this condition because of the lack of forward support of the sclerally fixated IOL. This means that it is of great importance not to stretch the sutures too hard, especially in a myopic eye. Breakage may also have been caused by the quality of the material forming the haptic of the single-piece aspherical IOL. The stiffness of the acrylic haptic of a single-piece IOL differs from that of a polymethylmethacrylate (PMMA) haptic. Acrylic material may be cut more easily by