Efficacy and Safety of CSF-1 (0.4% Pilocarpine Hydrochloride) in Presbyopia: Pooled Results of the NEAR Phase 3 Randomized, Clinical Trials.

PURPOSE: This study was undertaken to evaluate the safety and efficacy of CSF-1 (0.4% pilocarpine hydrochloride ophthalmic solution) for use in individuals with presbyopia. METHODS: Two Phase 3 multicenter, randomized, double-masked, vehicle-controlled, parallel-group clinical trials were conducted in 35 private ophthalmology clinics in the United States from October 2020 to February 2022. Key inclusion criteria were the following: (1) age 45-64 years, (2) distance-corrected near visual acuity (DCNVA) at 40 cm ≥0.40 and ≤0.90 logarithm of the minimum angle of resolution (logMAR, approximately 20/50-20/160 Snellen) in at least 1 eye, (3) manifest refraction (MR) between -4.50 and +2.00 diopter (D) sphere in each eye with ≤2.00D difference between eyes, (4) <2.00D of cylinder MR in each eye, (5) ≤0.04 logMAR (20/20-2 or better) corrected distance visual acuity (CDVA) at 4 m in each eye. Key exclusion criteria were the following: (1) >0.14 logMAR (7 letters) improvement in post-vehicle treatment in monocular DCNVA in either eye at visit 1, (2) introcular pressure (IOP) <9 or >22 mm Hg, (3) average dark-adapted pupillometry <3.5 mm in either eye, (4) prior refractive surgery or intraocular lens (IOL) implantation. Participants applied CSF-1 or vehicle twice per day for 2 weeks. Efficacy and safety assessments were performed at several times on days 1, 8, and 15. Response was defined as ≥3-line gain in DCNVA without loss of ≥1-line in CDVA in the study eye under mesopic room lighting conditions. The primary efficacy endpoint was measured 1 hour post-dose 1 on day 8. Key secondary endpoints were 2 hours post-dose 1, and 1 and 2 hours post-dose 2, also on day 8. Safety endpoints were ocular and non-ocular treatment-related adverse events (TRAE), conjunctival redness, drop comfort, slit-lamp biomicroscopy, intraocular pressure, indirect fundoscopy, and CDVA at 4 m. FINDINGS: Six hundred thirteen participants were randomized to CSF-1 (n = 309) or vehicle (n = 304). Participants were predominantly White (80.8%) and female (62.0%), with mean age (standard deviation) of 54.7 (4.8). CSF-1 met the primary and key secondary endpoints. At the primary endpoint, 40.1% of the CSF-1 group achieved response versus 19.1% of the vehicle group (P < 0.0001). The percentage of responders was significantly greater in CSF-1 compared with vehicle at all tested times. Changes from baseline in all safety endpoints were comparable between groups. Most adverse events (AEs) were mild and transient. Neither serious nor severe AEs were reported with CSF-1. IMPLICATIONS: CSF-1, a low-dose pilocarpine ophthalmic solution, demonstrated superiority to vehicle in improving near vision in individuals with presbyopia without compromising distance vision. CSF-1 demonstrated a favorable safety profile. CLINICALTRIALS: gov identifier: NCT04599933 (NEAR-1), NCT04599972 (NEAR-2).

Characterization of submicrojoule femtosecond laser corneal tissue dissection.

PURPOSE: To document the acute morphologic features of laser of situ keratomileusis (LASIK) flaps created using an IntraLase femtosecond laser (IntraLase, Inc.) with a 60 kHz engine. SETTING: Laser suite in a clinical practice. METHODS: A LASIK flap was created in 4 human eye-bank eyes using the 60 kHz IntraLase femtosecond laser with the following settings: 110 microm flap thickness, 9.0 mm flap diameter, 60-degree hinge length, 65-degree side cut, 0.4 muJ or 0.7 muJ raster energy, 7 microm x 7 microm or 9 microm x 9 microm spot/line separation, and 1 muJ side-cut energy. Immediately after the laser pass and without the flap being lifted, the globes were placed in fixative and subsequently processed for light and transmission electron microscopy. RESULTS: All 4 procedures were completed without complications or the appearance of an opaque bubble layer. The flaps were of uniform thickness and equaled the attempted thickness. Some areas had a complete dissection; other areas had scattered, incomplete tissue bridges. The adjacent corneal stroma and keratocytes were uninjured. When the epithelium was removed, the stromal component of the flap was measured as the attempted thickness; when the epithelium was present, the total flap thickness approximated the attempted flap thickness. CONCLUSIONS: Laser in situ keratomileusis flaps were safely created using raster energies and laser spot separations below those being used clinically. This technique may allow creation of flaps that are reproducibly thinner than those currently being performed and thus confer the benefits of surface ablation and LASIK.

Evaluation of a multifunctional femtosecond laser for the creation of laser in situ keratomileusis flaps.

PURPOSE: To characterize the performance of a multifunctional femtosecond laser system (Lensx) for the creation of laser in situ keratomileusis (LASIK) flaps. SETTING: Two surgical sites in the United States. DESIGN: Prospective case series pilot study. METHODS: Patients with myopia or hyperopia who were eligible for femtosecond laser-initiated LASIK surgery with corrected distance visual acuities (CDVA) correctable to at least 20/25 were enrolled. Central flap thickness accuracy (desired versus achieved) and precision (flap thickness standard deviation) were measured using anterior segment optical coherence tomography. Flap dissection quality, stromal bed quality, and amount of opaque bubble layer (OBL) formation were graded during surgery, and the refractive outcomes were evaluated postoperatively at 1-month and 3-month follow-ups. RESULTS: The study comprised 30 patients (58 eyes). At 3 months postoperatively, the flap thickness accuracy was 1.3 µm ± 2.6 (SD). A total of 78.3% of flaps were lifted with no resistance and 16.7% were lifted with minimal resistance using a blunt instrument. All (100%) stromal beds were determined to have a very smooth surface (grade 5 on a 0 to 5 scale). No OBL was observed in 73.3% of eyes; 26.7% of eyes showed an OBL occurring on less than 24% of the stromal bed surface. At 3 months postoperatively, most eyes (84.5%) had an uncorrected distance visual acuity of 20/20 and 98% had a CDVA of 20/20. The most common ocular adverse event was punctate keratitis (11.7%). CONCLUSION: The multifunctional femtosecond laser system effectively created LASIK flaps that were high quality, accurate, and precise.

"Top hat"-shaped penetrating keratoplasty using the femtosecond laser.

PURPOSE: To determine the feasibility of using a modified femtosecond laser to perform penetrating corneal resections. DESIGN: Controlled laboratory study. METHODS: Fourteen corneoscleral rims were mounted on an artificial anterior chamber. Eight underwent traditional penetrating keratoplasty (PKP) and six underwent "top hat"-shaped PKP using a femtosecond laser. Wound leakage pressure and induced astigmatism were compared between the two groups. RESULTS: Deep corneal resection with the femtosecond laser was feasible. Wound leakage occurred at 38 +/- 11 mm Hg in the traditional PKP eyes and at 240 +/- 69 mm Hg in the laser-shaped PKP groups. Initial induced astigmatism was 3.76 +/- 0.82 diopters and 3.46 +/- 1.36 diopters in the traditional and shaped PKP groups, respectively. CONCLUSIONS: Shaped PKP using the femtosecond laser is feasible and provides superior incision integrity compared to traditional PKP. Initial induced astigmatism is dominated by suture effects.

A 60 kHz IntraLase femtosecond laser creates a smoother LASIK stromal bed surface compared to a Zyoptix XP mechanical microkeratome in human donor eyes.

PURPOSE: To compare the stromal surfaces created by the latest mechanical microkeratome and femtosecond, laser technologies. METHODS: Laser in situ keratomileusis (LASIK) flaps were created in six fresh human globes unsuitable for transplantation. The eyes were placed in one of two groups of three globes each. One group had LASIK flaps created with a Zyoptix XP microkeratome using a 120-microm head and a fresh blade for each eye. Another group had flaps created at an attempted 100-microm thickness using the 60 kHz IntraLase femtosecond laser. Immediately following flap creation, the stromal beds were prepared for scanning electron microscopy (SEM). Qualitative roughness of the SEM images was graded by masked observers. Quantitative roughness of the SEM images was assessed using computerized software designed for roughness analysis. Mann-Whitney non-parametric statistical analysis was performed to compare groups. RESULTS: A statistically significant difference was noted in bed smoothness as measured by qualitative roughness and quantitative roughness scores. The IntraLase samples showed smoother stromal beds compared to the Zyoptix group (qualitative roughness = 2.0 +/- 0.7 pm vs 3.6 +/- 1.6 pm, P = .03; quantitative roughness = 20238 +/- 1869 pm vs 26368 +/- 8133 pm, P = .03). CONCLUSIONS: The 60 kHz IntraLase femtosecond laser and the Zyoptix XP 120-microm head using a new blade produced smooth, good quality, compact stromal beds qualitatively and quantitatively. Because the 60 kHz femtosecond laser permits a tight spot/line separation using low energy, it creates a smoother corneal stromal bed compared to previous femtosecond laser engines.

Femtosecond laser keratome creation of partial thickness donor corneal buttons for lamellar keratoplasty.

PURPOSE: To evaluate the thickness and diameter accuracy of the IntraLase femtosecond laser in harvesting corneal discs for lamellar keratoplasty. The stromal bed quality of resected corneas was evaluated by scanning electron microscopy. METHODS: Two IntraLase units were used to create corneal discs at 225-, 300-, 400-, and 500-microm thickness settings and 7-, 8-, 8.5-, and 9-mm diameter settings (n = 28). Achieved thickness was measured using a digital caliper and achieved diameter was measured using imaging software. Samples were preserved and processed for scanning electron microscopy to observe stromal bed quality. RESULTS: On both units, the mean deviation from attempted thickness was -9.5 +/- 8.6 microm (range: +6 to -28 microm). All of the obtained corneal discs were circular (horizontal versus vertical diameters, P > .05). The raster pattern produced a smoother stromal bed compared to the spiral pattern. CONCLUSIONS: The IntraLase femtosecond laser keratome provides depth and diameter accuracy even at increased depth settings. Stromal bed was smooth with the raster pattern and can further be smoothed by excimer phototherapeutic keratectomy treatment. Femtosecond laser lamellar keratoplasty is a promising procedure and clinical data are needed to determine effectiveness.

Comparative study of stromal bed quality by using mechanical, IntraLase femtosecond laser 15- and 30-kHz microkeratomes.

PURPOSE: To evaluate corneal stromal bed quality of lamellar keratectomy in laser in situ keratomileusis (LASIK) procedures by using mechanical and femtosecond laser microkeratomes. METHODS: LASIK corneal flaps were created in 9 fresh human globes not suitable for transplantation. We grouped the samples into 3 different groups of 3 globes each. Group 1 was the control group, in which the flaps were created using a Hansatome microkeratome with a 160-microm head. Groups 2 and 3 consisted of flaps created at the 110-microm flap thickness setting using the IntraLase 15- and 30-kHz femtosecond laser, respectively. All the flaps were removed, and the corneal stromal beds were prepared for scanning electron microscopy (SEM). Qualitative surface roughness (QlSR) of the SEM images was graded using a roughness grading scale from 1 to 5 by 3 masked observers. Quantitative surface roughness (QnSR) of the SEM images was also assessed using software designed for roughness analysis. Mann-Whitney nonparametric statistical analysis was performed to compare groups. RESULTS: There was no statistically significant difference in QlSR and QnSR scores between group 2 and group 1 (brand-new blade only). Group 3 30-kHz IntraLase samples showed a smoother stromal bed compared with group 1 and 2 samples. This was a statistically significant difference for QlSR (QlSR = 1.1 +/- 0.17, P < 0.001) and showed borderline significance for QnSR (QnSR = 24.4 +/- 0.96, P = 0.05). CONCLUSIONS: The IntraLase 15-kHz femtosecond laser 110-microm flaps and the Hansatome 160-microm head using a new blade both produced smooth, good-quality, compact stromal beds as assessed qualitatively by masked observers and quantitatively by image analysis software. The 30-kHz femotsecond laser permits a tighter spot/line separation and lower energy per pulse, which creates smoother corneal stromal beds.

INTACS inserts using the femtosecond laser compared to the mechanical spreader in the treatment of keratoconus.

PURPOSE: To determine the efficacy of INTACS insertion using a femtosecond laser in the treatment of keratoconus and to compare it to the technique using a mechanical spreader. METHODS: INTACS were inserted in 10 eyes using the mechanical spreader to create the channels and subsequently on another 20 eyes using the femtosecond laser. Uncorrected (UCVA) and best spectacle-corrected visual acuity (BSCVA), manifest refraction, and corneal topography were measured prior to surgery, at 6 months (femtosecond group), and 1 year (mechanical group). Pre- and postoperative data were analyzed to determine changes in the above parameters. RESULTS: Both groups showed significant reduction in average keratometry (K), spherical equivalent refraction, BSCVA, UCVA, surface regularity index (SRI), and surface asymmetry index (SAI). The laser group performed better in all parameters except change in SRI. Results of the laser versus the mechanical spreader were as follows: reduction in spherical equivalent refraction (3.98 vs 2.96), change in average K (2.91 vs 2.52), improvement in UCVA (4.13 vs 3.63), improvement in BSCVA (3.92 vs 1.63), change in SRI (0.37 vs 0.64), and change in SAI (1.00 vs 0.70). Statistical analysis, however, did not reveal any statistically significant differences between the two groups for any single parameter studied. The biggest improvement in the laser group versus the mechanical group was BSCVA (P=.09). Overall success, defined as contact lens or spectacles tolerance, was 85% in the laser group and 70% in the mechanical group. CONCLUSIONS: Inserting INTACS using the femtosecond laser to create the channels is as effective as using the mechanical spreader.

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.

Top hat wound configuration for penetrating keratoplasty using the femtosecond laser: a laboratory model.

PURPOSE: To evaluate the mechanical stability and induced astigmatism of a modified multiplanar "top hat" wound configuration for full-thickness penetrating keratoplasty (PK) using the femtosecond laser as compared with PK in a laboratory model. METHODS: Eight human corneoscleral rims were mounted on an artificial anterior chamber. Four samples were assigned to the traditional PK group. Four samples underwent full-thickness keratoplasty with the femtosecond laser: a 9.0-mm cylindrical cut was made from the anterior chamber into the stroma, followed by a ring-shaped (outer diameter 9.0 mm, inner diameter 7.0 mm) horizontal lamellar resection at two-thirds corneal depth and a 7.0-mm cylindrical cut from the lamellae to the corneal surface. Mechanical stability was evaluated after placement of the cardinal sutures and the running sutures. RESULTS: In the "top hat" PK group, wound leakage occurred at 19 +/- 3.36 mm Hg after placement of the cardinal sutures and at 86.25 +/- 9.74 mm Hg after placement of the running sutures. In the traditional PK group, leakage occurred at 0 +/- 0 mm Hg and 76.25 +/- 20.98 mm Hg after placement of the cardinal sutures and running sutures, respectively. Both techniques induced steepening of the corneal curvature postop. The modified wound group showed a mean change in average K of 3.43 +/- 3.62 D, whereas the traditional PK group showed a mean change in average K of 3.21 +/- 6.67 D. CONCLUSION: The femtosecond laser-produced "top hat" wound configuration for PK was found to be more mechanically stable than that produced by the traditional method.

In vivo femtosecond laser-assisted posterior lamellar keratoplasty in rabbits.

PURPOSE: To develop a rabbit model for femtosecond laser-assisted posterior lamellar keratoplasty. METHODS: The femtosecond laser was used to make the posterior corneal lamellar interface and trephine (side) cut in 12 eyes of 11 rabbits. Laser parameters were energy 6.0 to 8.7 (lamellar cut) and 6.0 to 8.8 microJ (trephination cut), spot size 2.4 microm, firing rate 15 kHz, and trephination diameter 6.0 to 7.0 mm. In all eyes, the posterior corneal disc was removed from the eye after laser treatment through a blade incision in the peripheral cornea. The same excised corneal disc was repositioned into the posterior stromal bed to simulate posterior lamellar transplantation. Four eyes of 3 rabbits were enucleated immediately after surgery, and 8 eyes of 8 rabbits were enucleated after a mean follow-up of 17.9 +/- 6.5 weeks. The corneal cut surfaces were examined by light microscopy and scanning electron microscopy. RESULTS: The femtosecond laser was successful in producing posterior lamellar and trephination cuts in rabbit eyes. The thickness of the posterior corneal discs was 204.3 +/- 21 microm (56.9% of central corneal thickness), and postoperative keratometry was 49.1 +/- 5.8 D. Clinical appearance consistent with corneal ectasia was noted in 3 eyes. CONCLUSION: The femtosecond laser can make nonmechanical cuts for posterior lamellar keratoplasty with relative ease and reliability in rabbit eyes. A minimum residual anterior corneal thickness may need to be maintained to prevent ectasia.

Ingress of India ink into the anterior chamber through sutureless clear corneal cataract wounds.

BACKGROUND: Sutureless clear corneal cataract incisions may be associated with an increased risk of endophthalmitis. OBJECTIVE: To assess the degree of ocular surface fluid ingress into the anterior chamber of cadaveric human globes with clear corneal wounds. METHODS: Self-sealing clear corneal incisions were created in 4 eyes, and intraocular pressure was controlled with an infusion cannula. To evaluate possible flow of surface fluid through the corneal wound, india ink was applied to the corneal surface while the intraocular pressure was varied, so as to simulate the intraocular pressure fluctuations secondary to blinking or eye squeezing. The optical density from aqueous samples of globes were measured both before and after india ink application using a spectrophotometer. RESULTS: Aqueous aspirates from the 3 globes with sutureless clear corneal wounds revealed a significant increase in spectrophotometric readings (P<.01), in contrast to the sutured wound, which did not show an increase in absorbance level relative to the baseline. Ink particles were both grossly and microscopically visible inside the sutureless corneal wounds. CONCLUSIONS: Fluctuations of intraocular pressure following sutureless clear corneal cataract surgery may allow entry of surface fluid into the anterior chamber during the initial postoperative period when the wound is not healed.

A technique to harvest Descemet's membrane with viable endothelial cells for selective transplantation.

PURPOSE: To describe a surgical technique using an artificial anterior chamber to facilitate harvest of Descemet's membrane (DM) and endothelium for corneal endothelial cell transplantation. DESIGN: Laboratory investigation. METHODS: Corneoscleral buttons of seven human donor eyes were mounted endothelial side up on an artificial anterior chamber. Keeping the endothelial side with its usual concavity, a manual trephination was made on the posterior surface with a 9.0-mm trephine, inside the Schwalbe line and just past the DM in depth. The chamber was filled with air, causing the endothelial side of the donor cornea to assume a convex configuration. The DM along with its endothelium was separated from the posterior stroma using a blunt cyclodialysis spatula. Drops of trypan blue 0.3% and alizarin red S 0.2% (n = 6) were applied. The stained DMs were examined under a light microscope and photographed to calculate the percentage of endothelial cell damage. Histology was done on the unstained cornea. RESULTS: The DM carrying endothelium was successfully removed from the posterior stroma in all seven eyes. Although the DM appears to be very friable, all samples were removed in toto without rupture. Vital staining showed a mean endothelial cell loss of 8.46% (standard deviation (SD) 6.9). Direct light microscopy demonstrated the preservation of endothelial cell morphology. CONCLUSIONS: This technique appears to be a safe and straightforward method to harvest DM for endothelial cell transplantation. Further studies are underway to determine the optimal method of insertion of the obtained healthy DM with endothelial cells through small corneal incisions.

Femtosecond laser posterior lamellar keratoplasty: a laboratory model.

PURPOSE: To evaluate feasibility of femtosecond laser application in posterior lamellar keratoplasty. METHODS: To evaluate the laser's effectiveness through opaque corneas, anterior corneal caps were resected from opaque corneas induced with 80% acetone solution. To evaluate the femtosecond laser posterior lamellar keratoplasty surgical procedure, human corneoscleral rims were mounted on an artificial anterior chamber. After corneal pachymetry, the femtosecond laser was used to create a 6-mm-diameter, 200-microm-thick endostromal lenticule. Access to the lenticule was provided by a small perilimbal surface opening, also created by the laser. The lenticule was removed using a pair of corneal forceps. A donor lenticule of similar dimensions was created, its endothelial surface coated with viscoelastic, inserted, and positioned on the recipient bed. Two sutures were placed to seal the small surface opening. RESULTS: The femtosecond laser produced an effective and smooth dissection through opaque corneas even at deeper settings. Graft transplantation was fairly simple and effective. CONCLUSION: Femtosecond laser posterior lamellar keratoplasty is a procedure that may provide an alternative to penetrating keratoplasty or the technically challenging manual posterior lamellar keratoplasty.

Femtosecond laser-assisted intracorneal keratoprosthesis implantation: a laboratory model.

PURPOSE: To demonstrate femtosecond laser-assisted intracorneal keratoprosthesis implantation and determine the mechanical stability as a function of intraocular pressure. METHODS: Eight human corneoscleral rims were mounted on an artificial anterior chamber. The femtosecond laser microkeratome was used to create a 2.5-mm diameter posterior corneal cap. A 7.2-mm-diameter lamellar stromal pocket was then created at mid-corneal depth. Finally, a 6-mm arc opening to the corneal surface was created at the periphery of the lamellar cut. The posterior lenticule was removed using corneal forceps and a 7.0-mm biopolymer keratoprosthesis was inserted into the stromal pocket. The surface wound was sealed using two 10-0 nylon sutures. A 3.0-mm anterior corneal opening was trephined to expose the keratoprosthesis. Intrachamber pressure was raised until wound leak was observed. RESULTS: Seven of the 8 implants withstood pressures of at least 135 mm Hg without implant extrusion. CONCLUSION: Femtosecond laser corneal dissection provides an alternative to more challenging manual dissection methods for keratoprosthesis implantation. Use of the femtosecond laser microkeratome will further refine keratoprosthesis surgical technique and may allow rapid and easy execution of the surgery.

Inflow of ocular surface fluid through clear corneal cataract incisions: a laboratory model.

PURPOSE: To evaluate the self-sealing properties of standard clear corneal cataract incisions during two events: (1) application of mechanical external pressure, or (2) controlled fluctuation of intraocular pressure (IOP). DESIGN: Laboratory investigation. METHODS: Eight fresh human donor globes were prepared for Miyake video microscopy. A standard two-plane 3-mm clear corneal incision was created and a 3 x 3-mm sponge soaked with India ink was placed on the wound surface. One globe with a sutured corneal wound served as the control. A transcleral cannula was inserted and connected to a bottle of saline. Intraocular pressure was modified varying the bottle height. External pressure was applied through manual contact on different regions of cornea. RESULTS: Four of seven eyes demonstrated intraocular presence of ink, three of them after external manipulation and another after varying the IOP. CONCLUSION: Self-sealing properties of unsutured clear corneal wounds were compromised in our model. These data may give insight into the possible mechanisms involved in the inflow of extraocular fluid into the eye through clear corneal cataract incisions.

Accommodating intraocular lens implantation in an epikeratophakia patient.

We report a case of implantation of the Crystalens AT-45SE and AT-52SE intraocular lenses in a highly myopic patient who had bilateral epikeratophakia surgery 15 years previously. Lessons learned from the first eye were taken into consideration when selecting the dioptric power for the fellow eye. With secondary interventions and meticulous lens calculations, the final outcomes were excellent and equivalent, allowing the patient to achieve uncorrected distance and intermediate visual acuities of 20/25 and near visual acuity of 20/50 in both eyes. To our knowledge, this is the first reported case of accommodating lens implantation in an epikeratophakic eye.

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.

In vitro measurement of rabbit corneal epithelial thickness using ultrahigh resolution optical coherence tomography.

The objective of this study was to reproducibly measure corneal epithelial thickness centrally and at the limbus in the rabbit cornea using ultrahigh resolution optical coherence tomography (OCT). Twelve freshly enucleated New Zealand white rabbit eyes were kept in a moist chamber at 4 degrees C. An ultrahigh resolution OCT system with a spatial resolution of 1.3 microm was used to image the cornea and its component layers. The central and peripheral (limbal) regions of all the samples were scanned within 6 h of harvest in order to minimize the post-mortem degradation of the corneal epithelium. The thickness of the corneal epithelium was determined by measuring the pixel equivalents of the obtained image. Unpaired Student's t-test was used to evaluate differences. The epithelial thickness centrally was found to be 45.8 +/- 2.2 microm, and 37.6 +/- 1.4 microm at the limbus (P < 0.001). Rabbit corneal epithelium is thicker centrally than at the limbus when measured by ultrahigh resolution OCT. This technique will aid in delineating the pathophysiology of diseases of the anterior cornea.