Evaluating the different laser fragmentation patterns used in laser cataract surgeries in terms of effective phacoemulsification time and power.

PURPOSE: To evaluate the effects of the different fragmentation patterns for the lens nucleus in terms of the effective phacoemulsification time (EPT) and power. SETTING: Shinagawa LASIK Center, Tokyo, Japan. DESIGN: Comparison study. METHODS: Seventy-one eyes of 71 patients had preoperative lens opacity grading based on the Emery-Little Classification (Grade 1 and Grade 2). Eyes underwent femtosecond laser-assisted cataract surgery (Catalys™ Precision Laser System), for capsulotomy and lens fragmentation. For the lens fragmentation, either the quadrants softened (Quadrant) or the quadrants complete (Complete) pattern was used. The mean EPT and phacoemulsification (phaco) power for each cutting pattern of Grades 1 and 2 cataracts were evaluated. RESULTS: The mean EPT was 28.96 seconds in the Quadrant Group and 16.31 seconds in the Complete Group (P=0.006). The mean phaco power was 8.07% in the Quadrant Group and 4.77% in the Complete Group (P=0.0002). Comparing the Quadrant and Complete Groups of Grade 1 cataract showed no significant difference in EPT (P=0.16), but showed a significant difference in phaco power (P=0.033). Comparing the Quadrant and Complete patterns of Grade 2 cataract showed significant differences in both EPT (P=0.012) and phaco power (P=0.003). Using the Complete pattern showed a 44.7% reduction in EPT and a 40.9% reduction in phaco power when compared to the Quadrant Group. CONCLUSION: Using the smaller fragmentation pattern in femtosecond laser cataract surgery, the phaco time and power were reduced significantly when compared to the procedure with the larger fragmentation pattern.

A new wavelet in the multifocal electroretinogram, probably originating from ganglion cells.

PURPOSE: To report the properties of a newly detected positive wavelet on the descending limb of P1 of the first-order kernel of the human multifocal electroretinogram (mfERG). METHODS: Twenty eyes of 20 normal individuals, ages 21 to 29 years (mean, 25.6) and nine eyes of 6 patients with optic neuritis ages 5 to 38 years (mean, 17.3) were studied. mfERGs were recorded with a visual evoked response imaging system with the number of stimulus elements set at 37. The stimulus frequency was changed from 75 to 37, 18, 9.4, 4.7, and 2.3 Hz, and the contrast of the stimuli was lowered to 50%. RESULTS: In normal eyes, a positive wavelet appeared on the descending limb of P1 of the first-order kernel of the mfERG when the stimulus frequency was reduced from 75 to 18 Hz. The wavelet had a mean amplitude of 4.2 nV/deg(2) and a mean implicit time of 34 ms at 18 Hz. When the stimulus frequency was reduced further to 2.3 Hz, the amplitude of the wavelet increased significantly (P < 0.05) compared with that at 18 Hz. The amplitudes of the wavelet elicited from the nasal side of the retina were significantly larger (P < 0.05) than those from the temporal side and decreased significantly (P < 0.05) with increasing distance from the optic disc. The wavelet was not present in any of the patients with newly diagnosed optic neuritis, but reappeared with recovery from the disease. The recovery of the wavelet correlated significantly with the recovery of visual acuity and of central critical fusion frequency. CONCLUSIONS: The amplitude of the wavelet on the descending limb of P1 of the first-order kernel of the mfERG was dependent on the stimulus frequency and the retinal locus. The wavelet was not present in the mfERGs recorded in patients with optic neuritis, but returned with recovery from the disease. These findings suggest that the neural activity of the ganglion cells give rise to this wavelet.

Effects of aging on the first and second-order kernels of multifocal electroretinogram.

PURPOSE: To determine the effects of aging on the first and second-order kernels of the multifocal electroretinogram (ERG). METHODS: Multifocal ERGs were recorded from 52 healthy subjects (52 eyes) (0 >or= refractive error >or= -3.0 diopter). The ages of the subjects ranged from 12-76 years with a mean (+/-SD) of 44.0 +/- 20.2 years. The Visual Evoked Response Imaging System was used. The effects of aging on the response densities and on the implicit times of the first positive wave (P1) of the first-order kernel, and of the second and third positive waves (P2 and P3) of the second-order kernel were analyzed for the different age groups. RESULTS: The response densities of the first-order kernel P1 and second-order kernel P2 waves decreased significantly, and the implicit times of the second-order kernel P2, and P3 were significantly prolonged (P <.05) in subjects over 50 years of age. CONCLUSION: The results suggest that the age of the subject should be considered when evaluating retinal function using multifocal ERGs in basic and clinical studies.

Accelerated versus conventional corneal collagen crosslinking.

PURPOSE: To compare the outcomes of accelerated corneal collagen crosslinking (CXL) and conventional corneal CXL. SETTINGS: Private practice, Tokyo, Japan. DESIGN: Comparative study. METHODS: Eyes with keratoconus had accelerated CXL (KXL system; 15 minutes riboflavin [Vibex Rapid] presoak; 3 minutes 30 mW/cm(2) ultraviolet-A [UVA] light) or conventional CXL (CCL-365 Vario system; 30 minutes riboflavin [Vibex] presoak; 30 minutes 3 mW/cm(2) UVA light). The postoperative changes in visual acuity, keratometry readings, morphologic changes in the cornea, demarcation line existence, and corneal biomechanical responses with accelerated CXL and conventional CXL were compared. The follow-up was 1 year. RESULTS: The study enrolled 48 eyes of 39 patients; 30 eyes had accelerated CXL, and 18 eyes had conventional CXL. There were no statistically significant differences in postoperative changes in uncorrected or corrected distance visual acuity or in the manifest refraction spherical equivalent between the 2 procedures. There were also no statistically significant differences in the postoperative changes in the keratometric readings from the Pentacam Scheimpflug device or the corneal biomechanical responses from a dynamic bidirectional applanation device (Ocular Response Analyzer) or a dynamic Scheimpflug analyzer (Corvis ST) between the procedures. Similar morphologic changes and a pronounced demarcation line were apparent in eyes in both groups postoperatively. CONCLUSIONS: Accelerated CXL and conventional CXL were both safe and effective. Accelerated CXL, being a fast procedure, appears to be more beneficial for patients and surgeons. FINANCIAL DISCLOSURE(S): No author has a financial or proprietary interest in any material or method mentioned.

High-irradiance accelerated collagen crosslinking for the treatment of keratoconus: six-month results.

PURPOSE: To evaluate the effectiveness of accelerated corneal collagen crosslinking (CXL) with riboflavin for keratoconus by the change in dioptric power and corneal topography. SETTING: Private practice, Tokyo, Japan. DESIGN: Case series. METHODS: The accelerated CXL treatments (KXL system) were performed using a 10-minute riboflavin 0.1% (Vibex Rapid) soak and a 3-minute ultraviolet-A (UVA) irradiance at a level of 30 mW/cm(2). This corresponds to a total radiant exposure of 5.4 J/cm(2). Preoperative and 1, 3, and 6 months postoperative examinations were performed. RESULTS: The study enrolled 39 eyes of 22 patients. The mean uncorrected distance visual acuity showed a statistically significant improvement, from 1.11 ± 0.42 logMAR preoperatively to 0.89 ± 0.53 logMAR 6 months postoperatively (P<.01). The mean maximum keratometry readings also changed significantly, from 49.95 ± 6.11 diopters (D) preoperatively to 49.19 ± 5.82 D at 6 months (P<.01). There were no statistically significant changes in the endothelial cell density between preoperatively and postoperatively. CONCLUSIONS: The changes after accelerated CXL were similar to those after conventional CXL. Thus, accelerated CXL has the potential to efficiently treat and halt the progression of keratoconus and may be an effective, efficient therapeutic option for treating corneal ectatic disease. FINANCIAL DISCLOSURES: No author has a financial or proprietary interest in any material or method mentioned.

Long-term observation and evaluation of femtosecond laser-assisted thin-flap laser in situ keratomileusis in eyes with thin corneas but normal topography.

PURPOSE: To evaluate the long-term outcomes of thin-flap laser in situ keratomileusis (LASIK) in eyes with thin corneas (central corneal thickness [CCT] <500 µm) but normal topography. SETTING: Private center, Tokyo, Japan. DESIGN: Retrospective randomized comparative study. METHOD: The efficacy, safety, predictability, and topography of LASIK were evaluated in eyes with a CCT of less than 500 µm but with normal topography (thin-cornea group) to 6 years postoperatively. The LASIK outcomes in the thin-cornea group were compared with those in eyes with a CCT of 500 µm or greater (control group). Analysis was performed to determine whether there were differences between the groups at the last checkup 3 to 4 years postoperatively. RESULTS: In the thin-cornea group (291 eyes; 146 patients), no significant differences were observed in LASIK outcomes when eyes were subdivided by the time of final checkup (3, 4, and ≥ 5 years). There was a significant difference in visual and refractive outcomes between 3 months postoperatively and the last checkup in the thin-cornea group and the control group (371 eyes; 193 patients). No significant difference in visual, refractive, or topography outcomes was observed between the 2 groups at the last checkup. CONCLUSIONS: Laser in situ keratomileusis in eyes with thin corneas was as safe and effective as and showed similar long-term stability in eyes with a CCT of 500 µm or greater. No eye in either group had a postoperative complication. FINANCIAL DISCLOSURE: No author has a financial or proprietary interest in any material or method mentioned.

Comparative study of 2 types of implantable collamer lenses, 1 with and 1 without a central artificial hole.

PURPOSE: To compare the outcomes between implantable collamer lenses (ICLs), 1 with and 1 without a central artificial hole. DESIGN: Comparative study. METHODS: We included 65 eyes of 65 patients with refractive error in our study. The mean manifest refraction spherical equivalent (MRSE) was -9.32 ± 4.02 diopters (range, 6.75 to -16.50 diopters). We divided patients into 2 groups based on the type of ICL used, 1 for those without a central artificial hole (Group I, 21 eyes) and 1 for those with a hole (Group II, 44 eyes). The postoperative changes in visual acuity, endothelial cell density, MRSE, higher order aberrations readings, and objective scatter index between the 2 kinds of ICLs were compared. The follow-up period was 3 months. RESULTS: There were no statistically significant differences in the postoperative changes in uncorrected distance visual acuity (P = 0.81), corrected distance visual acuity (P = 0.24), MRSE (P = 0.18), and endothelial cell density (P = 0.76) between the groups. Also, no difference in objective scatter index was found at 3 months (P = 0.32). None of the higher order aberrations readings showed any significant difference between the groups. CONCLUSION: There were no significant differences between the outcomes of these ICLs, either with or without a central artificial hole.

In vivo confocal laser microscopy of morphologic changes after simultaneous LASIK and accelerated collagen crosslinking for myopia: one-year results.

PURPOSE: To evaluate the safety of corneal collagen crosslinking (CXL) combined with laser in situ keratomileusis (LASIK). SETTING: Shinagawa LASIK Center, Tokyo, Japan. DESIGN: Case series. METHODS: Bilateral myopic LASIK patients had unilateral accelerated CXL (KXL System) in the nondominant eye. After LASIK, riboflavin 0.1% was instilled in the residual stromal bed for 60 seconds. After the riboflavin was washed out and the flap placed in its original position, ultraviolet-A light (30 mW/cm(2)) was administered for 60 seconds. The LASIK-CXL eyes and the LASIK-only eyes were compared. The uncorrected (UDVA) and corrected (CDVA) distance visual acuities, manifest refraction spherical equivalent (MRSE), keratometry values, endothelial cell density (ECD), pachymetry, optical coherence tomography (OCT), corneal hysteresis (CH), corneal resistance factor (CRF), keratoconus match index (KMI), and 37 parameters from a dynamic bidirectional applanation device (Ocular Response Analyzer) were analyzed. Morphologic changes were evaluated using confocal microscopy. RESULTS: No significant differences in UDVA, CDVA, MRSE, ECD, dynamic bidirectional applanation readings (eg, CH, CRF, KMI), or 37 additional parameters were found between the 2 groups (P>.05). Increased hyperreflectivity and a demarcation line similar to that seen after CXL were observed in the LASIK-CXL eyes. The demarcation line (mean depth 200.04 µm ± 27.01 [SD]; range 178 to 278 µm) was present in 23 eyes (95.8%); the line was well defined in 2 eyes (8.3%) and faint in 21 eyes (87.5%). CONCLUSION: Combined LASIK-CXL was safe, causing insignificant corneal biomechanical and morphologic changes similar to those with CXL treatment only. FINANCIAL DISCLOSURE: No author has a financial or proprietary interest in any material or method mentioned.

Corneal heat scar caused by photodynamic therapy performed through an implanted corneal inlay.

A 60-year-old man had a combination of laser in situ keratomileusis and Kamra corneal inlay implantation to correct presbyopia. Although the outcome was favorable postoperatively, central serous chorioretinopathy was observed in the left eye along with a decrease in the uncorrected (UDVA) and corrected (CDVA) distance visual acuities and the corrected near visual acuity (CNVA). Photodynamic therapy (PDT) was later performed in a university hospital. After PDT, the patient experienced a decline in the visual acuity and came to our clinic a month after the PDT. Degeneration and a scar were observed at the location of the inlay due to the heat and burning. Flattening of the corneal topography was also observed where the corneal scar was located, along with a significant decrease in CDVA in the left eye. Prior to any surgery in which the corneal inlay is an impediment, surgeons should take advantage of the reversibility of the Kamra inlay by explanting the inlay.