Mitomycin-C in corneal surface excimer laser ablation techniques: a report by the American Academy of Ophthalmology.

OBJECTIVE: To review the published literature assessing the efficacy and safety of mitomycin-C (MMC) as an adjunctive treatment in corneal surface excimer laser ablation procedures. METHODS: Literature searches of the PubMed and Cochrane Library databases were last conducted on August 19, 2014, without language or date limitations. The searches retrieved a total of 239 references. Of these, members of the Ophthalmic Technology Assessment Committee Refractive Management/Intervention Panel selected 26 articles that were considered to be of high or medium clinical relevance, and the panel methodologist rated each article according to the strength of evidence. Ten studies were rated as level I evidence, 5 studies were rated as level II evidence, and the remaining 11 studies were rated as level III evidence. RESULTS: The majority of the articles surveyed in this report support the role of MMC as an adjunctive treatment in surface ablation procedures. When MMC is applied in the appropriate concentration and confined to the central cornea, the incidence of post-surface ablation haze is decreased. Although a minority of studies that evaluated endothelial cell density (ECD) reported an MMC-related decrease in ECD, no clinical adverse outcomes were reported. CONCLUSIONS: Over the past 15 years, the use of MMC during surgery in surface ablation has become widespread. There is good evidence of the effectiveness of MMC when used intraoperatively as prophylaxis against haze in higher myopic ablations. Although there are reports of decreased endothelial counts after the administration of MMC during surgery, the clinical significance of this finding remains uncertain, because no adverse outcomes were reported with as much as 5 years of follow-up. Optimal dosage, effectiveness as prophylaxis in lower myopic and hyperopic ablations, and long-term safety, particularly in eyes with reduced corneal endothelial cell counts from prior intraocular surgery, have yet to be established.

The accuracy of the double-K adjustment for third-generation intraocular lens calculation formulas in previous keratorefractive surgery eyes.

PURPOSE: To evaluate the effect of the double-K (DK) modification on third-generation formulas. METHODS: Thirty-eight previously myopic and 24 previously hyperopic eyes that underwent phacoemulsification with intraocular lens (IOL) insertion after Laser in situ keratomileusis (LASIK) were evaluated. Pre-LASIK refraction and keratometry, post-LASIK topography, axial length (AL), IOL type and power, and 1-month postphacoemulsification refraction were recorded spherical equivalent after phacoemulsification (SE(postphaco)). Measured corneal power was adjusted using published and validated methods for postmyopic and posthyperopic LASIK. For each eye, and using SE(postphaco), different DK-IOL formulas were used to calculate the corresponding IOL power, the outcome measure, which was compared with the implanted IOL. RESULTS: DK-Holladay 1 yielded the highest Pearson correlation coefficient (PCC), 0.955 for myopes and 0.943 for high myopes (AL>26 mm). Mean error (ME) and mean absolute error (MAE) for myopes for DK Sanders-Retzlaff-Kraff theoretical formula [DK-SRK/T] were 0.44±0.84 D and 0.75±0.61 D for DK-SRK/T compared with -0.04±0.67 D and 0.52±0.40 D for DK-Holladay 1 (P<0.001 and P=0.016, respectively), and 0.03±0.88 and 0.64±0.58 for DK-Hoffer Q. For high myopes, ME and MAE were 0.75±0.81 D and 0.84±0.69 D for DK-SRK/T, and -0.05±0.74 D (P<0.0001) and 0.57±0.45 D (P=0.019) for DK-Holladay 1. About 29% of DK-SRK/T eyes with large AL had MAE>1.5 D, compared with 0% for DK-Holladay 1 and 14% for DK-Hoffer-Q. Eyes with previous hyperopic LASIK faired similarly for all formulas, with similar PCCs, and only 8% in each category with MAE>1.5 D. CONCLUSIONS: DK-SRK/T overestimates IOL power in eyes with large AL, especially with concomitant steep pre-lasik keratometry. Among third-generation formulas, DK-Holladay 1 seems more accurate to use in postmyopic LASIK eyes.

Comparative study of descemet stripping automated endothelial keratoplasty donor preparation by Moria CBm microkeratome, horizon microkeratome, and Intralase FS60.

PURPOSE: To evaluate the quality of stromal bed and the safety on endothelium in preparation of donor tissue for Descemet stripping automated endothelial keratoplasty in a masked fashion using 2 mechanical microkeratomes and a femtosecond laser. METHODS: Deep anterior lamellar dissection was performed on 15 donor corneas. Central endothelial cell density was calculated using specular microscopy before and after the dissection. One cornea from each of 5 donor pairs was cut with the Moria ALTK system with the CBm microkeratome using the 300-µm head and the mate cut with the Horizon disposable 300-µm microkeratome. Five additional donor corneas were cut with the Intralase 60-kHz FS laser. The donor corneas were then bisected with half of the cornea used for Live/Dead assay to study central endothelial viability. The other halves were sent for scanning electron microscopy of the stromal bed. Qualitative surface roughness of the scanning electron microscopy images was graded by 2 masked observers, and quantitative surface roughness was assessed using roughness evaluation software. RESULTS: The Horizon group showed a smoother stromal bed compared with the Moria or Intralase groups by 2 masked observers. However, the Moria group had the smoothest quantitative score of all the groups when assessed by roughness evaluation software. There was no statistically significant difference among the 3 groups in the percentage change in the central endothelial cell density or percentage of viable central endothelium by Live/Dead assay after the dissection. CONCLUSIONS: Both mechanical microkeratomes created smoother stromal bed dissections than the femtosecond laser. All systems provided good endothelial cell viability.

Apodized diffractive intraocular lens implantation after laser in situ keratomileusis with or without subsequent excimer laser enhancement.

PURPOSE: To evaluate the long-term refractive and visual outcomes of apodized diffractive multifocal intraocular lens (IOL) implantation after myopic laser in situ keratomileusis (LASIK) with or without subsequent excimer laser enhancement. SETTING: University of Texas Southwestern Medical Center at Dallas, Texas, USA. DESIGN: Comparative case series. METHODS: This study comprised consecutive patients who had implantation of an AcrySof ReSTOR multifocal IOL after previous LASIK. Included were eyes that had refractive surgery enhancement with a Visx Star S4 excimer laser for residual refractive error correction and eyes that had neodymium:YAG (Nd:YAG) capsulotomy. RESULTS: Of the 49 eyes (38 patients), 21 (42.9%) had laser enhancement and 25 (51.0%) had an Nd:YAG capsulotomy. The mean follow-up was 14.2 months ± 7.23 (SD) (range 9 to 29 months). Although the uncorrected distance visual acuity (UDVA) was significantly worse in eyes with enhancement than in those with no enhancement at 1 month and 6 months (P<.05), there was no significant difference in UDVA between the 2 groups at the last follow-up (P>.05). At the last follow-up, 36 (73.5%) of the 49 eyes had a UDVA of 20/25 or better and an uncorrected near visual acuity of Jaeger 1 or better concurrently; 46 eyes (93.9%) were within ±1.00 diopter (D) of emmetropia, and 41 (83.7%) were within ±0.50 D. CONCLUSION: Apodized diffractive multifocal IOL implantation and excimer laser enhancement in eyes with previous myopic LASIK provided good results.

Ophthalmic Manifestations of Stevens-Johnson Syndrome and Toxic Epidermal Necrolysis and Relation to SCORTEN.

PURPOSE: To evaluate the severity of ocular involvement of patients with Stevens-Johnson syndrome (SJS), toxic epidermal necrolysis (TEN), and SJS/TEN overlap, and to investigate the relationship of the SCORTEN (a severity-of-illness score for SJS and TEN based on a minimal set of well-defined variables calculated within 24 hours of admission) with eye disease in this patient population. DESIGN: Retrospective observational case series. METHODS: Charts of all patients admitted to the Parkland Memorial Hospital Burn Center with a preliminary diagnosis of SJS, SJS/TEN overlap, or TEN between 1998 and 2008 were reviewed. Patients were included for study if they met clinical criteria, had positive diagnostic skin biopsy, and had dermatologic and ophthalmologic consultations. Eighty-two patients with a diagnosis of SJS, SJS/TEN overlap, or TEN met inclusion criteria. Ocular manifestations were classified as mild, moderate, or severe. Admission data were used to calculate the SCORTEN. Main outcome measure was the severity of ocular involvement with respect to diagnosis and SCORTEN. RESULTS: Overall, 84% of patients had ocular involvement (71% SJS, 90% TEN, 100% SJS/TEN overlap). There was no difference in the severity of acute ocular complications among groups. While the SCORTEN value did correlate well with mortality rate (correlation coefficient 0.97, P = .005), there was no correlation between the SCORTEN value and severity of eye involvement in the acute setting. There was also no association of any individual diagnosis of SJS/overlap/TEN with the severity of eye involvement, although eye findings are more common in TEN (P = .03). CONCLUSIONS: Ocular damage in the acute setting was more frequent in patients with epidermal detachment >10% of the total body surface area. The SCORTEN value did not correlate with the severity of eye involvement in the acute setting.

Laser in situ keratomileusis for residual refractive errors after apodized diffractive multifocal intraocular lens implantation.

PURPOSE: To evaluate the visual and refractive outcomes of laser in situ keratomileusis (LASIK) to correct residual refractive error after apodized diffractive multifocal intraocular lens (IOL) implantation. SETTING: University of Texas Southwestern Medical Center, Dallas, Texas, USA. METHODS: This retrospective study reviewed eyes of consecutive patients who had LASIK using the IntraLase FS60 femtosecond laser and Visx Star S4 excimer laser to correct residual refractive error after AcrySof ReSTOR IOL implantation. RESULTS: The review comprised 85 eyes of 59 patients. Thirty-six eyes (42.3%) had myopic correction, 35 (41.2%) had mixed astigmatic correction, and 14 (16.5%) had hyperopic correction; 45 eyes (52.9%) also had neodymium:YAG (Nd:YAG) capsulotomy. Six months after LASIK, 91.8% of eyes had an uncorrected distance visual acuity (UCVA) of 20/25 or better, 92.9% had an uncorrected near visual acuity (UCNVA) of J1 or better, and 85.9% had 20/25 or better UCVA concurrent with J1 or better UCNVA. No eye lost more than 1 line of best spectacle-corrected visual acuity; 2 eyes (2.4%) lost 1 line. Ninety-nine percent of eyes were within +/-1.00 diopter (D) of emmetropia, and 98% of eyes were within +/-1.00 D cylinder. There was no significant difference in postoperative UCVA or UCNVA between the 3 refraction groups (P >.05) or between eyes that had Nd:YAG capsulotomy and those that did not (P >.05). CONCLUSION: Laser in situ keratomileusis for residual ametropia after apodized diffractive multifocal IOL implantation was predictable, effective, and safe.

Outcomes of PermaVision intracorneal implants for the correction of hyperopia.

PURPOSE: To report the clinical and visual outcomes of a series of patients implanted with the PermaVision intracorneal lens (ReVision Optics Inc, Lake Forest, California, USA) for correction of hyperopia. DESIGN: Prospective, nonrandomized, clinical trial study. METHODS: Fifteen patients were implanted with the intracorneal lens for correction of spherical hyperopic refractive errors ranging from 1.00 to 5.00 diopters (D) (mean, 2.45 D). All eyes were correctable to 20/20 before surgery. Patients were followed up to 3 years with measurements of residual refractive error, uncorrected visual acuity (UCVA), and best spectacle-corrected visual acuity (BSCVA). RESULTS: For patients with follow-up of 1 year or more, the mean logarithm of the minimum angle of resolution BSCVA was 0.15 (20/28 Snellen equivalent; range, 0.1 to 0.6) with an average change of -2.5 lines of BSCVA (range, 1 to -6 lines). Only 3 eyes (25%) achieved 20/20 or better UCVA. Two patients experienced early adverse events and 1 patient experienced a late-onset adverse event requiring eventual removal of the implant. Nine patients elected to have the implant removed, with dissatisfaction with the quality of vision as the most frequent reason for removal. CONCLUSIONS: The quality of visual and refractive outcomes with this device was less than satisfactory for most of the patients in our series. Although the problems of early onset migration or extrusion of the device are possible, late-onset ulceration noted in one of our patients most likely represents a neurotropic melt. Further research to improve the safety and quality of refractive result with intracorneal implants is needed.

Assessment of keratocyte activation following LASIK with flap creation using the IntraLase FS60 laser.

PURPOSE: To assess the response of corneal keratocytes to the IntraLase FS60 femtosecond laser using attenuated steroids. METHODS: Thirty patients (30 eyes) who underwent LASIK with the IntraLase FS60 were assessed by clinical examination and confocal microscopy 3 months postoperatively. Postoperative steroid regimen was Econopred Plus (Alcon Laboratories Inc) every hour for 1 day and four times daily for 7 days. RESULTS: No cornea had clinically significant flap interface haze. Two corneas had trace haze at the interface detected by slit-lamp examination; both showed significant keratocyte activation by confocal microscopy. Overall, some degree of keratocyte activation was detected at the flap interface in 10 of 30 eyes. The measured interface reflectivity was 328.8 +/- 85.0 confocal backscatter units (CBU) in eyes with activated keratocytes and 88.9 +/- 74.5 CBU for the remaining 19 eyes (P < .001). CONCLUSIONS: With attenuated steroids, keratocyte activation was found in a significant number of eyes, although interface haze was subclinical. A higher steroid dosage might therefore be indicated.

Intraocular lens power calculation after radial keratotomy: estimating the refractive corneal power.

PURPOSE: To evaluate the most accurate method for corneal power determination in patients with previous radial keratotomy (RK). SETTING: University of Texas Southwestern Medical Center at Dallas, Dallas, Texas, USA. METHODS: A retrospective review of data for 16 eyes of 14 patients with a history of RK and subsequent phacoemulsification and posterior chamber intraocular lens (IOL) implantation was performed. Outcome measures included axial length, postoperative topography, type and power of IOL implanted, and postoperative spherical equivalent (SE) refraction at 3 to 6 months. Average central corneal power (ACCP) was defined as the average of the mean powers of the central Placido rings. For each eye, simulated K-readings and different values of ACCP computed corresponding to different central corneal diameters were used in each case, along with the implanted IOL power, to back-calculate the SE refraction (Ref) via the double-K adjusted Holladay 1 IOL formula. The predicted refractive error was hence computed as (Ref - SE), both in algebraic and absolute values. RESULTS: The ACCP over the central 3.0 mm (ACCP(3mm)) yielded the lowest absolute predicted refractive error (0.25 +/- 0.38 diopters [D]), which was statistically lower than the error for ACCP(1mm) (P<.001) and for the simulated K-value (P = .033). It also resulted in 87.5% of eyes being within +/-0.50 D and 100% within +/-1.00 D of the actual postoperative refraction. CONCLUSIONS: Corneal refractive power after RK was best described by averaging the topographic data of the central 3.0 mm area. Applying this method, together with a double-K IOL formula, achieved excellent IOL power predictability.

Prospective evaluation of PermaVision intracorneal implants using in vivo confocal microscopy.

PURPOSE: To report effects of the PermaVision intracorneal lens at the cellular level using in vivo confocal microscopy. METHODS: Four eyes implanted with intracorneal lenses beneath an IntraLase flap for correction of hyperopia were evaluated preoperatively and 1 to 6 months postoperatively. RESULTS: Intracorneal lenses were tolerated in three eyes with little or no haze observed clinically and good visual results. Minimal keratocyte activation was detected by confocal microscopy, and cell density was decreased posterior to the implants. Epithelial thinning was observed 1 month after implantation. Thickness stabilized by 6 months but remained thinner than baseline (33 +/- 2 microm vs 48 +/- 8 microm, P < .01). The fourth eye had a complicated course with early flap displacement followed by diffuse lamellar keratitis. Confocal microscopy revealed activated keratocytes throughout the anterior stroma. The implant was removed, and recovery was promising. CONCLUSIONS: Implantation of intracorneal lenses can induce side effects of epithelial thinning, keratocyte loss, and keratocyte activation.

Comparison of the corneal response to laser in situ keratomileusis with flap creation using the FS15 and FS30 femtosecond lasers: clinical and confocal microscopy findings.

PURPOSE: To compare the response of the cornea to laser in situ keratomileusis (LASIK) with flap creation using the IntraLase FS15 or FS30 femtosecond laser (IntraLase Corp.). SETTING: Department of Ophthalmology, University of Texas Southwestern Medical Center, Dallas, Texas, USA. METHODS: Twenty-three patients (31 eyes) who had LASIK with flap creation using the FS15 or FS30 laser were assessed by clinical examination and confocal microscopy in a nonrandomized parallel treatment group comparative trial. Eight FS15 patients (15 eyes) were examined preoperatively and 3 months postoperatively, and 14 FS30 patients (15 eyes) were examined 3 months postoperatively. RESULTS: No patient in either group had clinically significant flap interface haze. One FS15 eye and 1 FS30 eye had significant keratocyte activation at the flap interface. The mean difference between the actual flap thickness and intended flap thickness was 16.8 microm +/- 11.1 (SD) and 13.9 +/- 7.1 microm in the FS15 group and FS30 group, respectively (P = .49). The mean measured interface reflectivity was 156.4 +/- 88.6 confocal backscatter units (CBU) and 104.8 +/- 91.2 CBU, respectively (P = .15). The mean density of interface particles was 21.4 +/- 14.8 particles/mm(2) in the FS15 group and 11.0 +/- 7.1 particles/mm(2) in the FS30 group (P<.05). CONCLUSIONS: Both the FS15 and FS30 lasers provided more reproducible flap thickness and fewer interface particles than previously observed using microkeratomes. The response of corneal keratocytes to intra-LASIK was reduced compared with previous results in which higher raster energies were used. Compared with the FS15, there was an apparent reduction in overall interface reflectivity and fewer interface particles with the FS30 laser.

Confocal assessment of the corneal response to intracorneal lens insertion and laser in situ keratomileusis with flap creation using IntraLase.

PURPOSE: To assess the response of the cornea to hydrogel intracorneal lens (ICL) insertion or laser in situ keratomileusis (LASIK) with IntraLase (IntraLase Corp.) at the cellular level. SETTING: Department of Ophthalmology, University of Texas Southwestern Medical Center, Dallas, Texas, USA. METHODS: Twenty patients (29 eyes) were evaluated by in vivo confocal microscopy 1 to 6 months postoperatively: 20 eyes had LASIK with flap creation by IntraLase, and 9 eyes had ICL insertion (8 following IntraLase). RESULTS: For LASIK with IntraLase, keratocyte activation and/or interface haze was detected in 8 of 20 eyes. The remaining eyes had interface particles but no cell activation. Keratocyte activation was generally limited to a few cell layers adjacent to the interface. However, 2 patients exhibited multiple layers of activation and increased extracellular matrix (ECM) reflectivity (haze) surrounding the interface by confocal microscopy. Both patients also had clinical haze and photophobia. For ICLs, following insertion, 5 of 9 eyes had activated keratocytes adjacent to the implant surfaces. The largest amount of cell activation and ECM haze detected by confocal microscopy was in 2 patients with significant clinical haze. Structures with an epithelioid morphology were detected on some implant surfaces. Epithelial thickness was 33.3 microm +/- 2.3 (SD) in the ICL eyes and 49.2 +/- 6.5 microm in the LASIK with IntraLase eyes. CONCLUSIONS: Both LASIK with IntraLase and ICL insertion following IntraLase induced keratocyte activation, which may underlie clinical observations of haze in some patients. Intracorneal lens implant also induced thinning of the overlying corneal epithelium.

Evaluation of intrastromal lipid deposits after intacs implantation using in vivo confocal microscopy.

PURPOSE: To assess the structure and location of intrastromal lipid deposits after implantation of Intacs by using in vivo confocal microscopy. METHODS: Seven eyes of six patients were examined by in vivo confocal microscopy 5 years (n = 6) or 2 months (n = 1) after uncomplicated implantation of Intacs for the correction of mild myopia. Selected images from all corneal layers were qualitatively evaluated for structural changes, with special attention paid to areas surrounding the Intacs implants. RESULTS: In the peripheral cornea of eyes examined 5 years after surgery, epithelial and endothelial cell layers appeared normal. Tandem scanning confocal microscopy showed stromal haze surrounding the implants in all eyes examined, but no keratocyte activation was seen. Reflective amorphous or crystalline structures consistent with lipid deposition were detected in all eyes with long-term implantation of Intacs. Deposits were localized to the inner and outer edges of Intacs segments and to the region anterior to the implant. Confocal microscopy did not show any deposits in the eye examined 2 months after surgery, although the region anterior to the implant appeared hazy and edematous. Areas central to the implant appeared normal in all eyes. CONCLUSIONS: The mechanical and physiologic stresses introduced by the implantation of Intacs lead to the accumulation of lipid deposits in the extracellular matrix. By using in vivo confocal microscopy, the location and structure of these deposits can be determined.