Karl G. Stonecipher

Advances in refractive surgery: microkeratome and femtosecond laser flap creation in relation to safety, efficacy, predictability, and biomechanical stability.

Purpose of review Methods of flap creation have changed over the years from the evolution of the mechanical microkeratome to the introduction of the IntraLase femtosecond laser keratome, both of which have different mechanisms of action to create corneal resections. Previous studies report the advantages and disadvantages of the mechanical microkeratome and the IntraLase femtosecond laser. The critical components in laser in-situ keratomileusis surgery remain the same, however: safety, efficiency, predictability, and biomechanical stability. Recent findings Keratoectasia and flap efficiency remain a constant safety concern in laser in-situ keratomileusis surgery. Unexpectedly thick flaps as well as variable thickness continue to be a concern with safety in relation to microkeratome technology. Epithelial preservation, flap complications, and newer issues such as Transient Light Sensitivity Syndrome are safety concerns of flap creation. Improved outcomes with regards to vision, induced astigmatism, induced higher-order aberrations, and enhancement rates are seen to favor predictability of femtosecond technologies over the microkeratome. Recent biomechanical studies show improved healing with femtosecond laser flap creation compared with blade-assisted flap creation. Summary The aim of this review is to summarize the key components for both the microkeratome and the femtosecond laser and to update on the recent advances reported on these topics.

Transient light sensitivity after femtosecond laser flap creation: Clinical findings and management

PURPOSE: To describe the constellation of subjective and objective findings associated with unusual occurrences of photosensitivity after laser in situ keratomileusis (LASIK) with femtosecond flap creation and identify optimal management strategies. METHODS: Demographic data, laser settings, subjective complaints, clinical findings, treatment, and response to treatment were recorded for suspected cases of transient postoperative photosensitivity from 3 surgeons operating at 3 different sites. All cases were estimated for the period covering the suspected cases at each site to assess incidence. Additional cases were solicited from IntraLase users via a survey. RESULTS: For the 3 sites, 63 eyes from 33 patients were reported of a total estimated case log of 5667 (incidence, 1.1%). Average age was 41 years, and 51.7% of patients were women. Onset of symptoms ranged from 2 to 6 weeks after uneventful LASIK. All patients were treated with prednisolone acetate drops, whereas 1 surgeon also used Restasis (cyclosporine ophthalmic solution 0.05%). Patients noted improvement of symptoms within 1 week of treatment. When the raster and side‐cut energy settings were lowered (by an average of 24% and 33%, respectively), significant reductions in incidence were noted. Similar findings were reported by 3 additional surgeons reporting 17 cases in the survey of IntraLase users. CONCLUSIONS: This report describes a new complication of LASIK performed with a femtosecond laser keratome that may be related to the pulse energy used for flap creation. Although there is no loss of uncorrected visual acuity, symptoms can be prolonged, especially without prompt steroid therapy. Technical advances that reduced pulse energies appear to decrease the incidence.

LASIK for −6.00 to −12.00 D of Myopia with up to 3.00 D of Cylinder Using the ALLEGRETTO WAVE: 3- and 6-Month Results with the 200- and 400-Hz Platforms

PURPOSE To report the refractive results after LASIK for high myopia and cylinder at one center with one surgeon comparing two laser platforms. METHODS A total of 206 eyes of 121 patients were treated for -6.00 to -12.00 diopters (D) of spherical equivalent refractive error with up to 3.00 D of cylinder. All eyes underwent LASIK with the ALLEGRETTO WAVE 200-Hz (n=141) or 400-Hz (n=65) laser (Alcon Laboratories Inc) between 2003 and 2009. Corneal flaps were created with the IntraLase femtosecond laser (Abbott Medical Optics) at an intended thickness of 100 or 110 μm in all cases. RESULTS At 3- and 6-month follow-up in the 200-Hz group, 77% (109/141) and 86% (121/141) of eyes, respectively, were within ±0.50 D of intended correction. In the 400-Hz group, 98.5% (64/65) and 100% (65/65) of eyes were within ±0.50 D of intended correction at 3 and 6 months postoperatively. At 3- and 6-month follow-up, 84% (119/141) and 77% (109/141) of eyes, respectively, in the 200-Hz group and 80% (52/65) and 92% (60/65) of eyes, respectively, in the 400-Hz group had 20/20 or better uncorrected distance visual acuity. At 6-month follow-up, refractive predictability and visual acuity were statistically superior in eyes in the 400-Hz group (chi square, P<.01). No eyes underwent retreatment as a secondary procedure during the time of analysis. CONCLUSIONS LASIK with the ALLEGRETTO WAVE 200- and 400-Hz laser is effective and predictable for the treatment of high myopia with astigmatism in appropriately selected patients. The acuity and predictability of refractive results may be slightly better when using the 400-Hz platform.

The IMPACT study: a prospective evaluation of the effects of cyclosporine ophthalmic emulsion 0.05% on ocular surface staining and visual performance in patients with dry eye

Objective The aim of this study was to evaluate the effects of cyclosporine ophthalmic emulsion 0.05% on ocular surface staining and visual performance in patients with dry eye. Methods This was a single-center, 6-month, open-label, Phase IV study. Patients with bilateral dry eye disease and a symptom score of ≥2 on the Ocular Discomfort and 4-Symptom Questionnaire, an Ocular Surface Disease Index score of >12, at least one eye with Schirmer’s score <10 mm/5 minutes, and central corneal staining graded as ≥2 on the Ora Calibra™ Corneal and Conjunctival Staining Scale were enrolled. Cyclosporine ophthalmic emulsion 0.05% (Restasis®) was instilled twice daily in each eye. The primary efficacy endpoints were ocular surface staining and visual function at 6 months. Secondary outcome measures included Schirmer’s test, tear film breakup time, symptoms, and adverse events. Results A total of 40 patients with the mean age of 59.4 years (range, 40–78 years) were enrolled; 35 (87.5%) were female and 37 (92.5%) completed the study. At 6 months, inferior corneal, central corneal, total corneal, and total ocular surface fluorescein staining were significantly improved from baseline in both eyes (P<0.001). Patient responses on the Ocular Surface Disease Index showed significant improvement in blurred vision and visual function related to reading, driving at night, working with a computer or bank machine, and watching television (P≤0.041). At 6 months, 35.1% of patients achieved ≥5 mm improvement and 18.9% achieved ≥10 mm improvement in the average eye Schirmer score. Mean tear film breakup time improved by >50% in both eyes (P>0.001). Patients reported significant improvement in ocular discomfort and dry eye symptoms (P<0.001). No patients discontinued treatment because of stinging or any other ocular adverse event. Conclusion Dry eye patients with difficulties with day-to-day visual function demonstrated improvement in both signs and symptoms of dry eye and reported improved visual function after 6 months of treatment with cyclosporine ophthalmic emulsion 0.05%.

LASIK for Mixed Astigmatism Using the ALLEGRETTO WAVE: 3- and 6-month Results With the 200- and 400-Hz Platforms

PURPOSE To report the refractive results after LASIK for mixed astigmatism at one center with one surgeon comparing two laser platforms. METHODS A total of 137 eyes of 69 patients were treated with LASIK for mixed astigmatism up to 3.33 diopters (D) using either the ALLEGRETTO WAVE 200- or 400-Hz laser (Alcon Laboratories Inc) between April 2006 and December 2009. The degree of astigmatism was higher in the 400-Hz group. Corneal flaps were created with the IntraLase femtosecond laser (Abbott Medical Optics) in all cases. RESULTS The refractive outcomes with both laser systems were statistically similar. At 6 months, 78% of eyes had 20/20 or better uncorrected distance visual acuity (UDVA) with all but one eye achieving 20/30 or better UDVA. At 6 months, 10% of eyes treated with the 200-Hz system lost one line of corrected distance visual acuity (CDVA) whereas no eyes treated with the 400-Hz system lost any lines of CDVA. Residual astigmatism was <0.50 D for all eyes treated with both platforms. CONCLUSIONS Both laser platforms provided predictable and effective treatment of mixed astigmatism in the patient populations treated, with over 90% of eyes achieving UDVA of 20/25 or better 6 months after surgery.

Results of topography-guided laser in situ keratomileusis custom ablation treatment with a refractive excimer laser.

Purpose To evaluate the safety and effectiveness of topography‐guided custom ablation treatment (T‐CAT) to correct myopia and myopic astigmatism with laser in situ keratomileusis (LASIK). Setting Nine clinical sites in the USA. Design Prospective observational nonrandomized unmasked study. Methods The study comprised patients aged 18 to 65 years old with myopia or myopic astigmatism with a manifest refraction spherical equivalent (MRSE) up to −9.0 diopters (D) and astigmatism of 6.0 D or less. Patients with previous refractive surgery or abnormal topography were excluded. Corneal topographies were obtained using the Allegro Topolyzer, and laser treatment was delivered with the Allegretto Wave Eye‐Q excimer laser system. Visual outcomes were evaluated postoperatively at 1 day, 1 week, and 1, 3, 6, 9, and 12 months. Results The clinical trial enrolled 212 patients (249 eyes). The T‐CAT procedure significantly reduced the MRSE and cylinder, with stability of outcomes evident from 3 to 12 months after surgery. Compared with the preoperative corrected distance visual acuity (CDVA), the postoperative uncorrected distance visual acuity (UDVA) improved by 1 line or more in 30% of eyes and the postoperative UDVA was at least as good as the preoperative CDVA in 90% of eyes. Most visual symptoms improved after T‐CAT. There were no significant treatment‐related adverse events or loss of vision. Conclusion The T‐CAT procedure performed with the diagnostic device and the refractive excimer laser system safely and effectively achieved predictable refractive outcomes and reduced visual symptoms with stable results through 12 months. Financial Disclosure Dr. Stulting is a paid consultant to Alcon Laboratories, Inc., and was a medical monitor for the U.S. Food and Drug Administration (FDA) clinical trial. Dr. Fant is president of Clinical Research Consultants, Inc. (CRC), the clinical and regulatory consulting group that sponsored the FDA clinical trial. Dr. Fant and CRC were supported by Alcon Laboratories, Inc.

Health claims database study of cyclosporine ophthalmic emulsion treatment patterns in dry eye patients

Background Dry eye is a multifactorial, symptomatic disease associated with ocular surface inflammation and tear film hyperosmolarity. This study was designed to assess patterns of topical cyclosporine ophthalmic emulsion 0.05% (Restasis®) use in dry eye patients and determine if there were any differences in use based on whether dry eye is physician-coded as a primary or nonprimary diagnosis. Methods Records for adult patients with a diagnosis of dry eye at an outpatient visit from January 1, 2008 to December 31, 2009 were selected from Truven Health MarketScan® Research Databases. The primary endpoint was percentage of patients with at least one primary versus no primary dry eye diagnosis who filled a topical cyclosporine prescription. Data analyzed included utilization of topical corticosteroids, oral tetracyclines, and punctal plugs. Results The analysis included 576,416 patients, accounting for 875,692 dry eye outpatient visits: 74.7% were female, 64.2% were ages 40–69 years, and 84.4% had at least one primary dry eye diagnosis. During 2008–2009, 15.9% of dry eye patients with a primary diagnosis versus 6.5% with no primary diagnosis filled at least one cyclosporine prescription. For patients who filled at least one prescription, the mean months’ supply of cyclosporine filled over 12 months was 4.44. Overall, 33.9% of dry eye patients filled a prescription for topical cyclosporine, topical corticosteroid, or oral tetracycline over 2 years. Conclusion Patients with a primary dry eye diagnosis were more likely to fill a topical cyclosporine prescription. Although inflammation is key to the pathophysiology of dry eye, most patients seeing a physician for dry eye may not receive anti-inflammatory therapies.

Complications Related to Femtosecond Laser-Assisted LASIK

Mechanical microkeratomes and femtosecond lasers have been the two methods used for LASIK flap creation. With either technique, LASIK has been shown to be a successful procedure, with equivalent visual outcomes and low complication rates. Studies have shown that compared with mechanical microkeratomes, femtosecond lasers provide safer and more predictable flap dimensions [1–11[12]]. However, the femtosecond laser can produce unique complications, which are not seen with the use of mechanical microkeratomes [7–11]. Complications can occur intraoperatively or postoperatively (Table 27.1).

Influences on Enhancement Rates in Laser Vision Correction

I ntroduction: The design of the study was to look consecutively at what are the prime influences on enhancements in laser vision correction related to the perioperative environment. Methods: A prospective consecutive series of 4,079 cases was reviewed from a single surgeon at a single surgical site. Patients were followed prospectively and were only included after at least two years of postoperative follow-up. Results: The series ranged in primary treatments of spherical equivalents (SE) from 0 to -12 diopters (D) with up to 4 D of cylinder. The preoperative average SE was -4.59±2.79 D and the cylinder average was -0.90±0.90 D. Uncorrected visual acuity (UCVA) prior to the enhancement was 0.63±0.23 (20/32) and post-enhancement was 0.99±0.20 (20/20). The top four influences on enhancements were presence of an opaque bubble layer (31.00%); dry eye disease (27.60%); history of ocular allergy (24.10%); and poor fixation (17.10%). Patients could have more than one of the above influences. Conclusions: Laser platforms, outcomes analysis, nomograms, and other influences will be discussed to help produce enhancement rates below 1.00%, which for this series was 0.71% overall.

Refractive Surgery Outcomes Comparison—All Wavefront-guided Versus a Decision Tree for Selecting Wavefront-guided or Wavefront-optimized

The purpose of this article is to compare refractive outcomes based on all wavefront-guided procedures versus a decision tree designed to assist with the selection of wavefront-guided or wavefront-optimized procedures. The setting was the The Laser Center, Greensboro. Twenty subjects were treated with a VISX CustomVue™ wavefront-guided refractive procedure in one eye and a WaveLight Allegretto procedure (wavefront-guided or optimized) in the contralateral eye. A decision tree was used to decide whether a wavefront-guided or wavefront-optimized procedure would be performed with the WaveLight system. The CustomVue eye was chosen at random. Visual acuity and refractive error were recorded pre-operatively and post-operatively. Subjective post-operative data included patient reported eye preference and post-operative glare and halos. The results were that one subject was lost to follow-up, leaving 19 subjects for analysis at three months. Of those subjects with data, 12 received wavefront-optimized treatment while seven subjects received a wavefront-guided treatment with the WaveLight laser. There were no significant differences in uncorrected visual acuity between the VISX and Wavelight groups at the one-day or six-month visits. At three months, 56 % of patients indicated no preference, with the remaining 44 % indicating a preference for the WaveLight-treated eye (p<0.05). The patient reported outcomes showed a similar incidence of post-operative glare and halos reported between the two treatments. Results with the Allegretto Wave Eye-Q laser, using a decision tree to determine whether a wavefront-optimized or a wavefront-guided treatment would be performed, were equivalent to those achieved with the VISX Star S4 wavefront-guided procedure.