Clinical results of topography-based customized ablations for myopia and myopic astigmatism.

PURPOSE: To evaluate clinical outcomes after primary treatments for myopia and myopic astigmatism with topography-based ablation profiles on the Allegretto Wave Eye-Q platform (Alcon Laboratories Inc). METHODS: Records of patients who underwent topography-guided, Q-adjusted LASIK were retrieved and analyzed. Patients with mean refractive spherical equivalent up to -16.00 diopters (D) and cylindrical errors up to 6.00 D were included (2051 eyes). Refractive outcomes and visual acuities were analyzed preoperatively and 3 months postoperatively. RESULTS: Manifest spherical refractive error decreased from -5.05 +/- 2.33 to +0.04 +/- 0.35 D. Manifest cylindrical refractive error decreased from 0.83 +/- 0.75 to 0.23 +/- 0.22 D. At 3 months postoperatively, 86.1% (1766 eyes) had a spherical equivalent refraction within +/- 0.50 D of targeted refraction. The number of eyes with uncorrected distance visual acuity of 20/16 and 20/20 was 851 (41.5%) and 1495 (72.9%), respectively. At 3 months, 0.10% (2 eyes) lost more than 2 lines of corrected distance visual acuity and a loss of 2 lines occurred in 0.24% (5 eyes). All patients who lost lines of visual acuity were found to have corneal erosions related to dryness and recovered vision on further follow-up. CONCLUSIONS: The results of this retrospective study demonstrate refractive predictability, efficacy, and safety comparable to other treatment modalities such as wavefront-optimized and wavefront-guided treatments. Results are also similar to those reported with other topography-guided systems.

Assessment of fibrin glue in pterygium surgery.

PURPOSE: To evaluate the efficacy and safety of fibrin glue in pterygium surgery with conjunctival autografting. METHODS: This was a prospective noncomparative case series. Patients were recruited from the general clinics for pterygium surgery. For pterygium surgery, autologous conjunctiva was harvested from the superior bulbar conjunctiva after pterygium excision. The graft was secured to bare sclera at the site of the pterygium by Tisseel fibrin adhesive. Patients were followed up with a standard form. Key parameters included visual acuity, graft integrity, and graft size. The rate of pterygium recurrence was monitored. RESULTS: A total of 24 patients were recruited, and 29 pterygia were excised with conjunctival grafting. All conjunctival grafts were secured adequately with no cases of dislodgement. Graft dimensions tended to decrease slightly in the early postoperative period, followed by stabilization. There were no cases of serious adverse events and no reduction in visual acuity. One pterygium recurrence occurred at 3 months. One spontaneous subgraft hemorrhage occurred with no effect on graft stability. CONCLUSIONS: Tisseel fibrin glue provided adequate adhesion of conjunctival grafts to the ocular surface. Healing was characterized by a comfortable eye, minimal inflammation, and good cosmetic result. There were no significant complications and the results appeared similar to those reported in the literature for sutured grafts.

Comparison of outcomes of lamellar keratoplasty and penetrating keratoplasty in keratoconus.

PURPOSE: To compare outcomes after penetrating keratoplasty (PK) and two techniques of deep anterior lamellar keratoplasty (DALK) in patients with keratoconus. DESIGN: Retrospective cohort study. METHODS: One hundred and twenty-five corneal transplantations comprising 100 PK and 25 DALK procedures for keratoconus at the Singapore National Eye Centre from April 1992 through December 2006 were included. DALK was performed with the modified Anwar technique (descemetic or DALKa group) in 14 eyes and manual lamellar keratoplasty (predescemetic or DALKm group) was performed in 11 eyes. RESULTS: At 12 months, the DALKa and PK groups achieved a logarithm of the minimum angle of resolution mean best spectacle-corrected visual acuity (BSCVA) of 0.15 and 0.27, respectively (P = .26), whereas the mean BSCVA of the DALKm group was 0.41 compared with the PK group (P = .12). Significance level was achieved between the DALKa and DALKm groups (P = .013). There was no significant difference in the mean spherical equivalent (P = .72) and astigmatism (P = .88) between the PK and DALK groups. The DALK group had a significantly lower incidence of complications compared with PK cases, including allograft rejection and glaucoma. Graft survival rate of both the PK and DALKa groups was 100%, whereas that of the DALKm group was 73% at 3 years after surgery (P = .000 between PK and DALKm groups). CONCLUSIONS: Visual acuity outcomes of the DALKa technique are comparable with those of PK for keratoconus, whereas DALK surgery results in fewer postoperative complications than PK. DALKa is emerging as a preferred choice among the lamellar techniques for better optical outcome. Further studies are required to provide long-term analysis of these results.

Glaucoma management in patients with osteo-odonto-keratoprosthesis (OOKP): the Singapore OOKP Study.

PURPOSE: To report diagnostic modalities and treatment options for glaucoma in eyes with osteo-odonto keratoprosthesis (OOKP). METHODS: Eyes that underwent OOKP were evaluated for glaucoma at the time of the first postoperative visit, then at 1 and 3 months after the procedure, and thereafter every 6 months. All eyes underwent stereo-biomicroscopic optic nerve head (ONH) assessment, kinetic (Goldmann perimetry) and automated static visual field testing, ONH photography, Heidelberg retina tomograph, scanning laser polarimetery (GDx), and optical coherence tomography. Treatment of glaucoma was also reviewed. RESULTS: Average follow-up period was 19.1 (range: 5 to 31) months. Of the 15 eyes that underwent OOKP, 5 eyes had preexisting glaucoma. None of the other 10 eyes developed glaucoma after OOKP. ONH photography and visual field testing were the most reliable methods to assess status of the disease, whereas Heidelberg retina tomograph and optical coherence tomography could be performed with reasonable reproducibility and quality; GDx imaging was poor. All patients with glaucoma were treated with oral acetazolamide 500 mg twice a day. Transscleral cyclophotocoagulation was performed in 3 eyes at stage 2 of OOKP surgery. Progression of glaucoma was noted in 2 eyes on the basis of optic disc photographs and automated perimetry. CONCLUSIONS: Visual field testing and optic disc assessment with optic disc photographs seem to be effective methods to monitor eyes with OOKP for glaucoma. Treatment strategies include oral medications to lower intraocular pressure and cyclophotocoagulation.

Acanthamoeba keratitis associated with contact lens wear in Singapore.

PURPOSE: To describe an outbreak of Acanthamoeba keratitis (AK) cases among contact lens wearers. DESIGN: Retrospective cohort study. METHODS: Patients with AK were included. Relevant demographic and clinical data were obtained from case records, and patients were interviewed using a standardized questionnaire. Contact lens practices, including type of contact lens and solution used, were noted. In addition, clinical features at presentation, management, and clinical outcomes were recorded. RESULTS: Forty-two patients (affecting 43 eyes) treated between 2000 and 2007 were included. Diagnosis was made by microbiologic culture in 35 cases and by microbiologic and histologic analysis in 2 cases, whereas the remainder were diagnosed based on clinical features and response to treatment. There was a gradual increase in cases since 2005, with a sharp increase in 2007, when 8 local patients were treated. Of 30 patients where contact lens solution data were available, 18 reported using a Complete brand Multipurpose solution (Advanced Medical Optics, Santa Ana, California, USA) before the infection. Among resident cases treated since February 2006, 7 (63%) of 11 patients used a Complete brand solution. Suboptimal hygiene practices were found in all patients interviewed. Fifteen patients required corneal grafting, with 11 undergoing therapeutic deep lamellar keratoplasty (DLK), 2 undergoing optical penetrating keratoplasty (PK), 1 undergoing optical DLK, and 1 undergoing therapeutic PK. The remainder were treated successfully medically with combination antiamebic therapy. The average duration of therapy was 116.2 days (range, 15 to 283 days). Of patients with radial keratoneuritis with or without epithelial disease, 83.3% achieved final vision of 20/40 or better, whereas this was achieved in 41.7% of those with ring infiltrate. Twenty-five percent of patients with ring infiltrate had final visual acuity of counting fingers or worse, whereas no patient with keratoneuritis and epithelial disease had final vision worse than counting fingers. CONCLUSIONS: There was an increase in the number of contact lens users with AK seen in the major eye departments of Singapore. Most of our patients also reported using a Complete brand Multipurpose solution before infection, and this parallels a similar outbreak in the United States. Increasing severity of infection was associated with worse visual outcome.

Intracameral fibrin tissue sealant as an adjunct in tectonic lamellar keratoplasty for large corneal perforations.

PURPOSE: To report a technique of intracameral injection of Tisseel fibrin sealant as an adjunct in the performance of tectonic deep anterior lamellar keratoplasty in cases with preexisting or intraoperative macroperforation. METHODS: Patients with corneal perforations up to 4 mm in greatest dimension first had the defect sealed externally with cyanoacrylate adhesive or fibrin sealant. An air bubble was injected into the anterior chamber (AC), followed by intracameral Tisseel fibrin sealant. This was injected via a 21-G cannula or needle, introduced into the AC from the limbus, with the tip positioned just under the perforation. Fibrin sealant was injected to completely cover the perforation site. Deep anterior lamellar keratoplasty then proceeded with a manual technique without chamber loss. Postoperatively, slit-lamp examination to assess resolution of fibrin sealant and graft status was performed, and visual acuities and intraocular pressures were recorded. RESULTS: Two patients with preexisting corneal perforations and 1 patient with an intraoperative perforation were included. In all patients, lamellar dissection proceeded uneventfully after intracameral fibrin injection. Fibrin sealant in the AC spontaneously resorbed by the second postoperative week. There were no postoperative intraocular pressure spikes and no cases of severe anterior uveitis. All grafts were clear at last follow-up with no evidence of endothelial decompensation. CONCLUSIONS: Intracameral fibrin sealant injection seems to be a safe adjunct to allow completion of deep anterior lamellar keratoplasty in cases with corneal perforation with the aim of avoiding higher risk penetrating keratoplasty. Cases were characterized by a lack of complications postoperatively, and no cases of persistent double AC were encountered.

Femtosecond laser creation of donor cornea buttons for Descemet-stripping endothelial keratoplasty.

PURPOSE: To evaluate the accuracy of the thickness and diameter of corneal disks obtained with the Femtec femtosecond laser (20/10 Perfect Vision) for Descemet-stripping endothelial keratoplasty (DSEK). SETTING: Singapore National Eye Centre, Singapore. METHODS: A femtosecond laser was used to create posterior stromal ablations at varying depths, producing donor lenticules 150 to 200 microm thick with diameters of 7.0 to 9.5 mm (n = 40). After stromal ablation, the central corneal thickness was measured by anterior segment optical coherence tomography and the diameters were measured using imaging software. RESULTS: The mean deviation from the attempted thickness was 15 +/- 14 microm. No correlation was found between the preoperative corneal thickness and the accuracy of the laser ablation (P = .91). No statistically significant differences were found in the accuracy of the laser ablation with multiple-pass nomograms (P = .15). The laser was accurate in producing circular diameters with an arc length between 7.0 mm and 9.5 mm (r2 = 0.935, P = .001). CONCLUSION: The femtosecond laser produced posterior stromal ablations that were accurate in depth of ablation and circularity.

Comparison of donor insertion techniques for descemet stripping automated endothelial keratoplasty.

OBJECTIVE: To evaluate the difference in endothelial cell damage between 2 donor insertion techniques for Descemet stripping automated endothelial keratoplasty (DSAEK). DESIGN: Experimental study and prospective case series. Thirty donor corneas and 10 patients undergoing DSAEK with glide insertion were included. Donor cornea lenticules were prepared and a wet lab DSAEK model established. Donor lenticules were inserted either by a "taco" fold (n = 15) or glide insertion (n = 15). Endothelial cell damage was assessed by scanning electron microscopy (n = 20) and trypan blue exclusion (n = 10). Endothelial cell count was assessed by specular microscopy in the clinical patients. RESULTS: Endothelial cell viability and scanning electron microscopy demonstrated 2 different patterns of cell damage in either group. Cell viability and scanning electron microscopy showed there was mean cell damage of 9% and 9.2% , respectively, following glide insertion and 32% and 38%, respectively, following the taco-folded insertion (P = .004). The mean (SD) cell loss in the clinical patients following glide insertion was 25.3% (4.3%) at 6 months. CONCLUSION: Endothelial cell damage was higher in a wet lab model following taco-folded insertion compared with glide insertion. Initial clinical results with glide insertion showed satisfactory endothelial cell loss at 6 months. Clinical Relevance Folding of the corneal tissue during DSAEK causes more endothelial damage than glide insertion.

Femtosecond laser-assisted endothelial keratoplasty: a laboratory model.

PURPOSE: To evaluate the ability of a 40-kHz femtosecond laser in performing posterior stromal ablation for endothelial keratoplasty. METHODS: Human corneoscleral rims were mounted on an artificial anterior chamber. After corneal pachymetry, the femtosecond laser was used to create a donor lenticule by using a variety of diameter ablations, 150 microm from the Descemet membrane. After ablation, the donor lenticule was peeled from the posterior surface and examined under light and scanning electron microscopy. Grading of ease of peeling and removing of the donor lenticule was assessed. RESULTS: The 40-kHz laser was able to produce effective dissection at low power in the posterior stroma. Modification of laser parameter settings was needed to improve the quality of stromal bed ablation. Double pass ablation of the bed significantly improved ease of peeling and removing of the donor lenticule. This was corroborated by smoother ablations on light and scanning electron microscopy. However, multiple pass ablations did not improve vertical rim dissections, which were satisfactory when single passes were used. CONCLUSIONS: Femtosecond laser-assisted endothelial keratoplasty is a viable alternative to microkeratome-assisted endothelial keratoplasty. Customized nomograms are needed for deep stromal ablation.

Keratoprosthesis surgery for end-stage corneal blindness in asian eyes.

PURPOSE: To establish a multidisciplinary surgical program for osteo-odonto-keratoprosthesis (OOKP) surgery in Asia and to evaluate efficacy and preliminary safety of this keratoprosthesis in end-stage corneal and ocular surface disease. DESIGN: Prospective noncomparative case series. PARTICIPANTS: Sixteen adults of Asian ethnic origin, bilaterally blind with end-stage corneal blindness from Stevens-Johnson syndrome, or severe chemical or thermal burns. METHODS: Osteo-odonto-keratoprosthesis surgery involves 2 procedures-in stage 1, an autologous canine tooth is removed, modified to receive an optical polymethyl methacrylate cylinder, and implanted into the cheek. The ocular surface is denuded and replaced with full-thickness buccal mucosa. Stage 2 surgery, performed 2 to 4 months later, involves retrieval of the tooth-cylinder complex and implanting it into the cornea, after reflection of the buccal mucosal flap, corneal trephination, iris and lens removal, and anterior vitrectomy. Concurrent glaucoma and vitreoretinal procedures are also performed at either stage, as required. MAIN OUTCOME MEASURES: Visual acuity (VA), field of vision, anatomical integrity and stability, and ocular and oral complications related or unrelated to the OOKP device. RESULTS: Osteo-odonto-keratoprosthesis surgery was performed on 15 patients, with a mean follow-up of 19.1 months (range, 5-31). Intraoperative complications included expulsive hemorrhage (keratoprosthesis device not implanted), tooth fracture (n = 1), oronasal fistula (n = 1), and mild inferior optic tilt (n = 1). Anatomical stability and keratoprosthesis retention has been maintained in all eyes, with no dislocation, extrusion, retroprosthetic membrane formation, or keratoprosthesis-related infection. Other complications not directly related to device insertion included retinal detachment (RD) related to silicone oil removal (n = 1) and endophthalmitis related to endoscopic cyclophotocoagulation performed 1 year after OOKP surgery (n = 1). Eleven patients (73.3%) attained a stable best spectacle-corrected VA of at least 20/40 or better, whereas 9 (60%) attained stable 20/20 vision. Four patients achieved their best visual potential, ranging from 20/100 to counting fingers vision, related to preexisting glaucomatous optic neuropathy or previous RD. CONCLUSIONS: Establishment of our OOKP program suggests that OOKP surgery has the potential to restore good vision to the most severe cases of corneal blindness in an Asian setting, with minimal device-related complications. Longer follow-up of these cases is currently underway.

Using a "small bubble technique" to aid in success in Anwar's "big bubble technique" of deep lamellar keratoplasty with complete baring of Descemet's membrane.

AIM: To describe the "small bubble" technique to immediately determine the success of attaining complete Descemet's membrane (DM) separation from corneal stroma via Anwar's "big bubble" technique of deep anterior lamellar keratoplasty (DALK). METHODS: A partial trephination was followed by a lamellar dissection of the anterior stroma. Deep stromal air injection was then attempted to achieve the big bubble to help separate the stroma from the DM. To confirm that a big bubble has been achieved a small air bubble is injected into the anterior chamber (AC) via a limbal paracentesis. If the small bubble is then seen at the corneal periphery, it confirms that the big bubble separation of DM has been successfully accomplished, as the convexity of the bubble will protrude posteriorly forcing the small AC bubble to the periphery. If the small AC bubble is not seen in the corneal periphery, this means that it is present centrally, beneath the opaque corneal stroma, and therefore the big bubble has not been achieved. We used the small bubble technique to confirm the presence of the big bubble intraoperatively in a keratoconus patient. RESULTS: Complete stromal removal with baring of the descemet's membrane was achieved and postoperatively the patient achieved best corrected vision of 6/6. CONCLUSION: The small bubble technique helps in confirming the separation of DM from the deep stroma, which is important in achieving the goal of total stromal replacement. To view the full report and accompanying video please go to: http://bjo.bmj.com/cgi/content/full/92/3/422/DC1 All videos from the BJO video report collection are available from: http://bjo.bmj.com/video/collection.dtl.

Glide insertion technique for donor cornea lenticule during Descemet's stripping automated endothelial keratoplasty.

We describe a simple technique for inserting the donor corneal lenticule in Descemet's stripping automated endothelial keratoplasty. Unlike the standard insertion method, which requires folding the donor lenticule, this technique uses a modified intraocular lens (IOL) glide to guide the unfolded donor lenticule through the small incision with an intraocular forceps. This prevents significant endothelial trauma and surgical difficulties when the lenticule is unfolded. Additional endothelial protection is provided by an ophthalmic visco-surgical device on the IOL glide, which protects the donor endothelium from the corneal wound edge and prevents iris prolapse during insertion.

Use of a "small-bubble technique" to increase the success of Anwar's "big-bubble technique" for deep lamellar keratoplasty with complete baring of Descemet's membrane.

PURPOSE: To describe a quick and simple "small-bubble" technique to immediately determine the success of attaining complete Descemet's membrane (DM) separation from corneal stroma through Anwar's "big-bubble" technique of deep anterior lamellar keratoplasty (DALK) for complete stromal removal. METHODS: A partial trephination was followed by a lamellar dissection of the anterior stroma. Deep stromal air injection was then attempted to achieve the big bubble to help separate the stroma from the DM. To confirm that a big bubble had been achieved, a small air bubble was injected into the anterior chamber (AC) through a limbal paracentesis. If the small bubble is then seen at the corneal periphery, it confirms that the big-bubble separation of DM was successful because the convex nature of the bubble will cause it to protrude posteriorly, forcing the small AC bubble to the periphery. If the small AC bubble is not seen in the corneal periphery, this means that it is present in the centre, beneath the opaque corneal stroma, and therefore the big bubble has not been achieved. RESULTS: We used the small-bubble technique to confirm the presence of the big bubble in three (one keratoconus, one interstitial keratitis and one dense corneal scar) out of 41 patients who underwent DALK. The small-bubble technique confirmed that the big bubble was achieved in the eye of all three patients. Complete stromal removal with baring of the DM was achieved, and postoperatively all three eyes achieved best corrected vision of 6/6. CONCLUSION: The small-bubble technique can be a useful surgical tool for corneal surgeons attempting lamellar keratoplasty using the big-bubble technique. It helps in confirming the separation of DM from the deep stroma, which is important in achieving total stromal replacement. It will help to make the transition to lamellar keratoplasty smoother, enhance corneal graft success and improve visual outcomes in patients.

Trisection technique: a 2-snip approach to intraocular lens explantation.

We describe a new explantation technique that allows an intraocular lens (IOL) to be removed through the small incisions used in modern cataract surgery. After the IOL optic is freed from the capsular bag, a Vannas scissors is used to cut it into 3 pieces via a temporal clear corneal incision. A Sinskey hook inserted via a paracentesis located 90 degrees away provides a stabilizing counterforce, preventing optic slippage as the blades of the scissors close. We believe this method provides a simple and effective way to remove IOLs via very small incisions, thereby hastening patient recovery and improving outcomes.

Current treatment options for corneal ectasia.

PURPOSE OF REVIEW: The approach to the management of various forms of corneal ectasia is changing, with the advent of new surgical and nonsurgical options. The purpose of this review is to summarize and evaluate relevant studies on new treatments for keratoconus, postrefractive surgery keratectasia, and peripheral ectatic corneal disorders. RECENT FINDINGS: Various alternatives to corneal transplantation for the management of keratoconus aim to enhance corneal rigidity by means of nonsurgical collagen cross-linking, or with the use of intrastromal corneal ring segments, and studies suggest that these treatments may reduce astigmatism or ectatic progression to varying degrees. Recent developments in anterior lamellar keratoplasty enable targeted replacement or augmentation of corneal stroma without replacement of endothelium, and include procedures such as deep anterior lamellar keratoplasty, microkeratome or laser-assisted anterior lamellar surgery, and peripheral tectonic lamellar keratoplasty procedures demonstrate successful reinforcement of peripheral stroma to reduce astigmatism. SUMMARY: These new forms of surgery are viable alternatives to conventional penetrating keratoplasty and bring added safety profiles for long-term visual rehabilitation and restoration of tectonic integrity in central and peripheral forms of corneal ectasia.

Posterior-assisted levitation: outcomes in the retrieval of nuclear fragments and subluxated intraocular lenses.

PURPOSE: To report the outcomes of posterior-assisted levitation (PAL) to retrieve nuclear fragments and subluxated intraocular lenses (IOLs). SETTING: Singapore National Eye Centre, Singapore, Singapore. METHODS: In a retrospective series, the case notes of consecutive surgeries performed by a single surgeon between 1999 and 2006 were reviewed. Posterior-assisted levitation was performed for intraoperative posterior capsule rupture with nucleus-IOL dislocation or for late subluxation of posterior chamber intraocular lenses (PC IOLs). This was accomplished by the pars plana insertion of a needle followed by levitation of the subluxated object. Ophthalmic viscosurgical device injection was not used as an adjunct for levitation. RESULTS: Fourteen patients with PAL were followed for a mean of 18.71 months (range 1 to 79 months). There were 3 cases of dropped nucleus/nuclear fragments, 1 case of intraoperative subluxated PC IOL, and 10 cases of late subluxated PC IOLs. Complications included 1 case of retinal detachment occurring 20 months after PAL and 1 case of cystoid macular edema in a patient with previous anterior uveitis. Best corrected visual acuity was 20/40 or better in all except 3 patients (1 retinal detachment, 1 corneal edema/scarring, 1 unspecified). CONCLUSION: Posterior-assisted levitation provided an effective, relatively noninvasive means of levitating nuclear fragments and PC IOLs with few complications.

Spontaneous disinsertion of a multipiece foldable acrylic intraocular lens haptic 3 and 12 months after implantation.

We report 2 cases of spontaneous postoperative haptic disinsertion with the Alcon AcrySof MA60BM posterior chamber intraocular lens (PC IOL). A 14-year-old girl with a history of acute retinal necrosis and pars plana vitrectomy with lensectomy for retinal detachment repair had secondary implantation of a PC IOL in the ciliary sulcus. Three months later, the superior haptic disinserted from the optic and dislocated into the anterior chamber. In the second case, a 22-year-old man had lens aspiration and PC IOL implantation in the capsular bag. One year after surgery, the PC IOL had a similar problem, with the disinserted superior haptic remaining in the capsular bag while the optic and inferior haptic dislocated into the anterior chamber. In both patients, the PC IOLs were exchanged for rigid single-piece PC IOLs. The patients have had no further problems.