David S. Rootman

Comparison of Posterior Lamellar Keratoplasty Techniques to Penetrating Keratoplasty

PURPOSEnTo describe the visual outcomes and intraoperative and postoperative complications after penetrating keratoplasty (PK), deep lamellar endothelial keratoplasty (DLEK), Descemet stripping endothelial keratoplasty (DSEK), and Descemet stripping automated endothelial keratoplasty (DSAEK) and to compare the results with those of previously reported series.nnnDESIGNnProspective, comparative, nonrandomized study.nnnPARTICIPANTSnOne hundred seventy-seven eyes of 161 consecutive patients who had corneal edema resulting from Fuchs endothelial dystrophy, pseudophakic bullous keratopathy, aphakic bullous keratopathy, failed graft or iridocorneal endothelial syndrome.nnnMETHODSnAll patients underwent either PK, DLEK, DSEK, or DSAEK at the Cornea Service of the Toronto Western Hospital.nnnMAIN OUTCOME MEASURESnUncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), manifest refraction, corneal endothelial counts, and postoperative complications.nnnRESULTSnThe average 12-month postoperative BSCVA was 20/53 in the PK group, 20/80 in the DLEK group, 20/56 in the DSEK group, and 20/44 in the DSAEK group. The mean spherical equivalent was similar between groups, but tended toward hyperopia in the DSEK and DSAEK groups. The average refractive astigmatism was 3.78+/-1.91 diopters (D) in the PK group and 1.61+/-1.26 D, 1.86+/-1.1 D, and 1.36+/-0.92 D in the DLEK, DSEK, and DSAEK groups, respectively (P<0.0001). Early postoperative donor disc dislocations occurred in 6 (8.8%) patients in the DLEK group, 2 (12.5%) in the DSEK group, and 7 (15.6%) in the DSAEK group (P = 0.0004). Detached grafts were reattached and repositioned by injecting an air bubble to press the donor against the recipient cornea. Primary graft failure occurred in 1 (2.1%) of the PK cases, 2 (2.9%) of the DLEK cases, and 1 (2.2%) of the DSAEK cases; all underwent the same procedure successfully. Average cell loss at 1 year after surgery was 40.11% and was similar in the 4 groups.nnnCONCLUSIONSnThe DSAEK surgery enabled rapid and better UCVA and BSCVA when compared with PK, DLEK, and DSEK, with significantly lower astigmatism. Endothelial cell loss was similar, but the dislocation rate was significantly higher in the DSAEK group.

Comparison of Three Different Techniques of Corneal Transplantation for Keratoconus

PURPOSEnTo compare the visual outcomes following deep anterior lamellar keratoplasty (DALK), penetrating keratoplasty (PK), and manual top-hat PK (TH-PK) in subjects undergoing corneal transplantation for keratoconus (KC).nnnDESIGNnA retrospective comparative case series.nnnMETHODSnsettings: Cornea clinic at the Toronto Western Hospital. study population: Fifty patients who underwent corneal transplantation for KC: 17 eyes underwent DALK, 20 eyes underwent traditional PK, and 13 had TH-PK. main outcome measures: Preoperative and postoperative uncorrected and best spectacle-corrected visual acuity (UCVA, BSCVA), high-order aberrations (HOA), complication rate, and endothelial cell counts.nnnRESULTSnThe median BSCVA at 12 months follow-up was 20/40 in the DALK eyes and 20/30 in the traditional PK and TH-PK eyes. The mean final spherical equivalent power in the three groups was less than -1 diopter (D). The median astigmatism was less than 3.5 D in the three groups. Complication rates were similar for three groups, although the DALK group tended toward more complications. Although DALK and TH-PK procedure results in significantly shorter time to suture removal (P < .01), they caused increased levels of HOAs (P = .02). Endothelial cell counts at 12 months were significantly higher in DALK and TH-PK eyes when compared to the traditional PK eyes (P < .001).nnnCONCLUSIONSnDALK, PK, and TH-PK provide comparable visual outcomes in keratoconus patients. Although DALK and TH-PK induce more HOA, they speed up the time to suture removal and provide higher endothelial cell density at one year of follow-up.

SUBCONJUNCTIVAL BEVACIZUMAB INJECTION FOR CORNEAL NEOVASCULARIZATION IN RECURRENT PTERYGIUM

Purpose: We report on the use of subconjunctival bevacizumab on corneal vessel density in recurrent pterygia.Methods: The charts of 5 patients with recurrent pterygium, who received subconjunctival injections of bevacizumab (2.5 mg/0.1 ml) were retrospectively reviewed. Ophthalmic evaluation included Snellen visual acuity (VA), tonometry and complete examination before the injection and at 1 week and 1 and 3 months thereafter. Digital photographs of the eyes were analyzed by image analysis software to determine the area of cornea covered by new vessels as a percentage of the total corneal area. Results: No ocular or systemic adverse events were observed. No change in visual acuity was noted in any patient following the injection. The mean change in corneal vascularization after one bevacizumab injection was 0.03% ± 0.45, while after two injections the change was 0.025% ± 0.19 (both not statistically different than zero, t-test). Conclusions: Short-term results suggest that subconjunctival bevacizumab is well tolerated but does not cause regression of corneal vessels in recurrent pterygium.

Busin Guide vs Forceps for the Insertion of the Donor Lenticule in Descemet Stripping Automated Endothelial Keratoplasty

PURPOSEnTo compare two insertion methods in Descemet stripping automated endothelial keratoplasty (DSAEK): Busin guide-assisted vs Forceps-assisted insertion of the corneal lenticule graft.nnnDESIGNnProspective, consecutive, comparative, nonrandomized study.nnnMETHODSnsetting: Cornea clinic at the Toronto Western Hospital. study population: Sixty-three eyes of 63 consecutive patients were included. All patients underwent DSAEK for Fuchs endothelial dystrophy, pseudophakic bullous keratopathy, aphakic bullous keratopathy, failed graft, or iridocorneo endothelial syndrome. Twenty-six consecutive donor discs were inserted with the Busin guide and 37 consecutive eyes underwent forceps assisted insertion of the donor. main outcome measures: Uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), manifest refraction, corneal endothelial cell loss, and postoperative complications.nnnRESULTSnBusin guide-assisted DSAEK group had significantly worse UCVA and lower donor endothelial cell counts preoperatively. No significant differences were noted in the intraoperative or postoperative complications. Six months following surgery, BCVA was not significantly different between groups: 20/37 in the Busin guide-assisted DASEK group vs 20/42 in the Forceps-assisted group (P = .39). Mean spherical equivalent was -0.02 diopters (D) and 0.82 D (P = .06), and mean refractive cylinder was 2.2 D and 1.31 D (P = .0006), respectively. Endothelial cell loss was significantly lower in the Busin guide-assisted DASEK group: 25% loss vs 34.3% loss in the Forceps-assisted DSAEK group. (P = .04).nnnCONCLUSIONSnAlthough visual outcomes were not different between the groups studied, Busin guide-assisted DSAEK resulted in lower percentage of endothelial cell loss compared with forceps insertion, six months following surgery.

Comparison of central corneal thickness measurements by specular microscopy, ultrasound pachymetry, and ultrasound biomicroscopy.

Purpose: To compare the reproducibility and mean values of central corneal thickness (CCT) obtained by specular microscopy, ultrasound pachymetry, and ultrasound biomicroscopy (UBM). Setting: Department of Ophthalmology, University of Toronto, Toronto, Ontario, Canada. Methods: Thirty‐one healthy volunteers were recruited for a sample size of 62 eyes. All subjects had pachymetric measurements by specular microscopy, ultrasound pachymetry, and UBM. Three separate measurements meeting criteria for centrality and perpendicularity were recorded for each eye. Results: The mean CCT by specular microscopy was 572 &mgr;m (95% confidence interval (CI), 566‐578 &mgr;m), which was significantly greater than 550 &mgr;m (95% CI, 545‐556 &mgr;m) (P<.001) and 555 &mgr;m (95% CI, 550‐560 &mgr;m) (P<.001) by ultrasound pachymetry and UBM, respectively. The mean standard deviation (SD) of repeated measurements by specular microscopy was 7.82 &mgr;m, which was significantly greater than the mean SDs of 4.14 &mgr;m (P<.001) and 3.90 &mgr;m (P<.001) by ultrasound pachymetry and UBM, respectively. There was no statistically significant difference between the mean SDs by ultrasound pachymetry and UBM (P=.156). Conclusions: Although the CCT measurements by specular microscopy were significantly less reproducible than those by ultrasound pachymetry and UBM, the error levels were clinically acceptable. Both ultrasound pachymetry and UBM produced similar CCT measurements, which were significantly less than those generated by specular microscopy. One should be aware of the advantages and limitations of each machine and of possible differences in the CCT measurements by optical and ultrasound pachymetry.

Shifting Trends in Bacterial Keratitis in Toronto: An 11-Year Review

OBJECTIVEnTo review the distribution, current trends, and resistance patterns of bacterial keratitis isolates in Toronto over the last 11 years.nnnDESIGNnRetrospective, observational, case series.nnnPARTICIPANTSnMicrobiology records of suspected bacterial keratitis cases that underwent a diagnostic corneal scraping and cultures from January 1, 2000, through December 31, 2010, were reviewed.nnnMETHODSnCulture results and antibiotic sensitivity profiles were reviewed and analyzed.nnnMAIN OUTCOME MEASURESnDistribution of the main isolated pathogens as well as in vitro laboratory minimum inhibitory concentration testing results to identify resistance patterns.nnnRESULTSnA total of 1701 consecutive corneal scrapings were taken during the 11 years of the study. A pathogen was recovered in 977 samples (57.4%), with bacterial keratitis accounting for 897 of the positive cultures (91.8%). The total number of Gram-positive and Gram-negative isolates was 684 and 213, respectively. We identified a decreasing trend in Gram-positive isolates (P = 0.016). The most common isolate overall was coagulase-negative Staphylococcus (CNS) and the most common Gram-negative bacteria isolated was Pseudomonas aeruginosa. Methicillin-resistant Staphylococcus aureus (MRSA) was present in 1.3% of the S aureus isolates, whereas methicillin-resistant CNS (MRCNS) was present in 43.1% of the CNS isolates. There was a trend toward increasing laboratory resistance to methicillin from 28% during the first 4 years of the study to 38.8% for the last 3 years (P = 0.133). When analyzing the sensitivities of MRSA and MRCNS isolates to other antibiotics, there was resistance to cefazolin and sensitivity to vancomycin in all isolates, whereas resistance to other antibiotics was variable.nnnCONCLUSIONSnThere was a significant decrease in the percentage of Gram-positive microorganisms over time. The sensitivity of Gram-negative isolates to tested antimicrobials was >97% response for all the reported antibiotics; this was not the case for Gram-positive isolates, in which resistance to the antibiotics was more common. Methicillin-resistant organisms accounted for 29.1% of all Gram-positive cultures in our series, suggesting that the empiric use of vancomycin in the setting of severe suspected bacterial keratitis may be justified.

IntraLase-enabled astigmatic keratotomy for post-keratoplasty astigmatism: on-axis vector analysis.

PURPOSEnTo determine the refractive predictability, stability, efficacy, and complication rate of femtosecond laser-enabled astigmatic keratotomy for post-keratoplasty astigmatism.nnnDESIGNnA retrospective case series (pilot study).nnnPARTICIPANTSnThirty-seven eyes of 34 patients.nnnMETHODSnAll eyes underwent IntraLase-enabled astigmatic keratotomy for high astigmatism (>5 diopters [D]) after penetrating keratoplasty.nnnMAIN OUTCOME MEASURESnUncorrected visual acuity (UCVA), best-corrected visual acuity (BCVA), manifest refraction, higher-order aberrations, and complications.nnnRESULTSnMean follow-up was for 7.2 months. Uncorrected visual acuity improved from a mean of 1.08+/-0.34 logarithm of the minimum angle of resolution preoperatively to a mean of 0.80+/-0.42 postoperatively (P=0.0016). Best-corrected visual acuity improved from a mean of 0.45+/-0.27 preoperatively to 0.37+/-0.27 postoperatively (P=0.018). The defocus equivalent was significantly reduced by more than 1 D (P=0.025). The value of absolute astigmatism was reduced from 7.46+/-2.70 D preoperatively to 4.77+/-3.29 D postoperatively (P=0.0001). Higher-order aberrations were significantly increased. The efficacy index was 0.6+/-0.6. There were no cases of perforation, wound dehiscence, or infectious keratitis. Three eyes (8%) experienced an episode of graft rejection. Overcorrection occurred in 9 eyes (24%).nnnCONCLUSIONSnIntraLase-enabled astigmatic keratotomy is an effective treatment for high astigmatism after penetrating keratoplasty with an encouraging refractive predictability. Future studies may help refine the treatment parameters required to achieve reduction of cylinder with greater accuracy.

Intrastromal corneal ring segment SK implantation for moderate to severe keratoconus

PURPOSE: To report the efficacy and safety of intrastromal corneal ring segment (ICRS) implantation using a femtosecond laser in the management of advanced keratoconus. SETTING: Private laser center, Toronto, Ontario, Canada. METHOD: In this retrospective nonrandomized study, Intacs SK ICRS were implanted using an IntraLase femtosecond laser in eyes with moderate to severe keratoconus. Evaluation included uncorrected (UDVA) and corrected (CDVA) distance visual acuity, manifest refraction, slitlamp examination, corneal topography, and wavefront analysis of higher‐order aberrations. Postoperative visits were at 1, 7, and 30 days and 3 and 6 months. RESULTS: The study evaluated 10 eyes of 8 patients with a mean age of 28 years (range 21 to 42 years). The mean UDVA was significantly better 6 months postoperatively than preoperatively (0.66 logMAR ± 0.21 [SD] versus 1.19 ± 0.57 logMAR) (P = .004), as was the mean CDVA (0.25 ± 0.15 logMAR versus 0.51 ± 0.20 logMAR) (P = .018). The mean spherical equivalent refractive error was −8.08 diopters (D) preoperatively and −5.03 D at 6 months (P = .65); the mean refractive astigmatism, −5.05 D and −3.90 D, respectively (P = .22); and the mean simulated keratometry value, 57.94 D and 50.07 D, respectively (P = .15). The mean total aberration improved significantly, from 13.48 ± 4.64 &mgr;m preoperatively to 9.42 ± 1.80 &mgr;m postoperatively (P = .007). There were no complications. CONCLUSION: Implantation of ICRS for advanced keratoconus was safe and effective, leading to significant improvement in UDVA, CDVA, and total aberrations. Financial Disclosure: No author has a financial or proprietary interest in any material or method mentioned.

Suture-Assisted vs Forceps-Assisted Insertion of the Donor Lenticula during Descemet Stripping Automated Endothelial Keratoplasty

PURPOSEnTo compare a new insertion method using a suture with the standard forceps-assisted insertion of the lamellar corneal graft in Descemet stripping automated endothelial keratoplasty (DSAEK).nnnDESIGNnInterventional, comparative case series.nnnMETHODSnDSAEK was performed on 28 consecutive eyes of 28 patients (mean age +/- standard deviation, 72.5 +/- 9.7 years; 12 males). The donor tissue was prepared using the Moria automated lamellar therapeutic keratectomy microkeratome head with a 300-mm blade depth on a Moria artificial anterior chamber (Moria, Antony, France). The central 9 mm of the recipients Descemet membrane were stripped through a superior limbal incision. In eight consecutive unselected patients, a 10-0 monofilament suture on a long straight needle was used to insert the folded donor lenticula into the recipients eye, whereas in the other 20 patients, a standard insertion forceps was used. During the suture insertion, an anterior chamber maintainer was used to fill the anterior chamber continuously with balanced salt solution to prevent its collapse.nnnRESULTSnSuture-assisted DSAEK did not differ significantly from forceps-assisted DSAEK in any of the preoperative parameters. No significant differences were noted in the intraoperative or postoperative complications. Six months after surgery, there were no significant differences in endothelial cell counts (1804 vs 1935 cells/mm(2), respectively), visual acuity (20/40 vs 20/36, respectively), or refraction (spherical equivalent, 0.93 vs 1.05 diopters, respectively).nnnCONCLUSIONSnSuture-assisted DSAEK is a valid alternative to forceps insertion; however, it does not seem to offer a significant advantage.

Phacoemulsification and intraocular lens implantation in nanophthalmic eyes: Report of a medium-size series

Purpose: To evaluate the outcomes in nanophthalmic eyes that had phacoemulsification and intraocular lens (IOL) implantation. Setting: Toronto Western Hospital, University of Toronto, Toronto, Ontario, Canada. Methods: Six nanophthalmic eyes of 4 patients had uneventful phacoemulsification and posterior chamber IOL implantation with a retrobulbar or peribulbar block. All operations were performed by 1 surgeon. Patients ranged in age from 41 to 70 years. Results: The visual acuity remained stable or improved in all 6 eyes. Glaucoma control was maintained or improved in 5 eyes. Conclusion: The results indicate that small‐incision cataract surgery, although challenging, is safe and diminishes the need for prophylactic sclerotomies in these high‐risk eyes.