Riboflavin injection into the corneal channel for combined collagen crosslinking and intrastromal corneal ring segment implantation.

PURPOSE: To evaluate the effectiveness of intracorneal riboflavin injection for combined collagen crosslinking (CXL) and intrastromal corneal ring segment (ICRS) implantation. SETTING: Kudret Eye Hospital, Ankara, Turkey. DESIGN: Noncomparative case series. METHODS: Keratoconic eyes had combined ICRS (Intacs) implantation and transepithelial CXL with 20% alcohol application and riboflavin injection into the corneal channel. Outcome measures were uncorrected (UDVA) and corrected (CDVA) distance visual acuities, sphere, cylinder, and keratotomy (K) readings. RESULTS: The study enrolled 131 eyes (105 patients) with a mean follow-up of 7.07 months ± 4.66 (SD). The mean improvement was 0.26 ± 0.16 logMAR in UDVA and 0.24 ± 0.16 logMAR in CDVA (both P<.05). The mean manifest spherical refraction decreased from -3.87 ± 4.55 diopters (D) to -1.25 ± 2.31 D, the mean manifest cylinder improved from -3.89 ± 1.97 D to -2.27 ± 2.18 D, and the mean K reading improved from 50.50 ± 5.26 D to 46.03 ± 4.51 D (all P<.05). There were no intraoperative or postoperative complications. CONCLUSIONS: Combined ICRS and CXL treatment with intracorneal riboflavin injection was effective in keratoconic eyes. Intracorneal riboflavin injection into the tunnel was safe and may provide more penetration without epithelial removal. FINANCIAL DISCLOSURE: No author has a financial or proprietary interest in any material or method mentioned.

Change in biomechanical parameters after flap creation using the Intralase femtosecond laser and subsequent excimer laser ablation.

PURPOSE: This study aims to investigate the effect of both flap creation and laser ablation on corneal hysteresis (CH) and corneal resistance factor (CRF), as well as the inward applanation signal amplitude produced by the ocular response analyzer (ORA), immediately following each step of the LASIK procedure using the Intralase femtosecond laser for flap creation. METHODS: A total of 66 eyes of 35 subjects who underwent Intra-LASIK surgery were prospectively enrolled in this study. Changes in the CH, CRF, and amplitude of the first applanation peak (Peak 1) of the infrared signal were measured preoperatively, immediately after flap elevation and repositioning, as well as subsequent to laser ablation in all eyes. Repeated measures analysis of variance (ANOVA) was performed with a post-test of contrast variable profiles to investigate changes following each step of the procedure. RESULTS: The repeated measures ANOVA indicated a significant difference (p < 0.001) among the three time points for CH, CRF, and Peak 1. There was no significant change in CH (p = 0.20) or CRF (p = 0.57) after flap creation, but there was significant decrease in these parameters following laser ablation (p < 0.0001), when compared to values obtained pre-operatively. There was a significant decrease in Peak 1 both after flap creation (p < 0.0001) and after subsequent ablation (p < 0.0001), when compared to pre-operative ORA signal peak amplitudes. CONCLUSION: There is a well documented change in corneal biomechanical properties following a LASIK procedure. This study reveals that this change may be predominantly due to laser ablation. However, flap creation with the Intralase laser does produce a biomechanical consequence consistent with reduction of corneal stiffness, as measured by the reduced amplitude of Peak 1. CH and CRF do not fully characterize this change.

Location of steepest corneal area of cone in keratoconus stratified by age using Pentacam.

PURPOSE: To evaluate topographic patterns in keratoconic cases and to classify those topographic patterns according to different age groups. METHODS: Four hundred eighty-two eyes of 251 patients with keratoconus were separated into 3 groups based on age. The age range of group 1 (younger) was <21 years (83 eyes), group 2 (middle) was 21 to 40 years (362 eyes), and group 3 (older) was >40 years (37 eyes). All patients underwent full ocular examination and Pentacam (Oculus Optikgeräte GmbH) measurement. Topographic patterns were analyzed by comparing the results according to age groups. RESULTS: Distribution ratios of keratoconic eyes in the three age groups were 17.2% younger, 75.3% middle, and 7.5% older. The most frequent topographic patterns for those patients were vertical bowtie pattern (28.4%) in the younger group, inferior global cone pattern (23.7%) in the middle group, and inferotemporal global cone pattern (16.4%) in the older group. Temporal global cone pattern was more frequently seen among younger keratoconus patients--22% for the eyes in the younger group, 6.9% for the eyes in the middle group, and 11.1% for the eyes in the older group. CONCLUSIONS: In keratoconus, the steepest part of the cone can be located temporally, especially in younger patients, which is unusual. Younger candidates for refractive surgery should be screened for temporal forme fruste.

Refractive and topographic results of transepithelial cross-linking treatment in eyes with intacs.

PURPOSE: To evaluate the efficacy of transepithelial cross-linking (CXL) in keratoconic eyes after Intacs implantation. PATIENTS AND METHODS: Twenty-five eyes of 17 patients with bilateral keratoconus underwent Intacs implantation with subsequent cross-linking (CXL) treatment. Inclusion criteria were absence of corneal scarring, contact lens intolerance, corneal thickness higher than 400 mum, and endothelial cell density more than 3000 per square millimeter. Preoperative and 3-month-postoperative uncorrected visual acuity (UCVA), best-corrected visual acuity (BCVA), manifest refractions, and mean and steepest keratometric (K) values were reviewed retrospectively. The results in Intacs group were compared with those obtained after CXL/Intacs. RESULTS: There were 10 males and 5 females; mean age was 25.14 +/- 7.11 (range 16-39) years old. Mean time between implantation of Intacs and CXL was 3.98 months. CXL after Intacs resulted in an additional improvement in UCVA, BCVA, sphere, cylinder, and keratometry. Intacs resulted in an improvement of 1.9 Snellen lines (P < 0.05) of UCVA and 1.7 Snellen lines (P < 0.05) of BCVA. CXL performed after Intacs treatment yielded an additional 1.2 Snellen lines (P < 0.05) of UCVA and 0.36 Snellen lines (P < 0.05) of BCVA. The decrease in spherical, cylindrical, mean K, and steepest K values was 2.08 diopters (D) (P < 0.05), 0.47 D (P > 0.05), 2.22 D (P < 0.05), and 1.27 D (P < 0.05), respectively, after Intacs treatment with an additional 0.5 D (P < 0.05), 0.15 D (P > 0.05), 0.35 D (P > 0.05), and 0.76 D (P < 0.05) of improvement gained after CXL in each respective parameter. CONCLUSIONS: Intacs implantation with transepithelial CXL is effective in eyes with keratoconus. Collagen cross-linking has an additive effect on Intacs implantation in these eyes and may be considered as an enhancement/stabilizing procedure.

Measurement of depth of Intacs implanted via femtosecond laser using Pentacam.

PURPOSE: To measure the depth of intracorneal ring segments (Intacs, Addition Technology Inc) implanted via femtosecond laser by Pentacam rotating Scheimpflug camera (Oculus Optikgeräte GmbH) and to determine the change in depth at 1-year follow-up. METHODS: Thirty-two eyes of 23 keratoconic patients receiving Intacs intrastromal corneal ring segments implanted by femtosecond laser were included in the study. The depth of intracorneal channel and Intacs segments were measured for 7 predetermined points at 1 week and 1 year postoperatively using Scheimpflug images. RESULTS: Mean achieved intrastromal channel depth exceeded the intended parameter by 6.5 microm to 69.0 microm. The standard deviation varied between +/- 13.5 microm and +/- 44.2 microm. The segment depth decreased at the end of the first postoperative year in all measured points, and the change was statistically significant at the superior, inferior, and temporal sides of the Intacs. The degree of change was not correlated with size of the Intacs, preoperative central corneal thickness, and mean keratometric values. CONCLUSIONS: Pentacam provided imaging of the Intacs segments and measurement of their depth, enabling evaluation of the changes in depth at 1-year follow-up. The Intacs segments tended to shallow over time, which may be a factor for depth-related complications.

Epithelial ingrowth after femtosecond laser-assisted in situ keratomileusis.

PURPOSE: To describe the incidence and clinical features of epithelial ingrowth after femtosecond laser-assisted in situ keratomileusis (LASIK). METHODS: All eyes with clinically significant epithelial ingrowth were identified from patients who underwent primary femtosecond laser-assisted LASIK and their subset of patients who underwent enhancement procedures from January 2005 to March 2007 at Kudret Eye Hospital. Clinical course in terms of severity, type of epithelial ingrowth, time of appearance, effect on visual acuity, and treatment was described for each patient. RESULTS: Two eyes of 6415 eyes after primary procedure and 2 eyes of 108 eyes after enhancement procedure developed clinically significant epithelial ingrowth. All eyes were treated with surgical removal of epithelial ingrowth. The epithelial ingrowths in all the patients were seen as solitary islands of cells, with a size ranging between 1 and 3 mm, beneath the flap with no connection with the surface epithelium. There was recurrence of ingrowth in 1 eye. CONCLUSIONS: Visually significant epithelial ingrowth after femtosecond laser-assisted LASIK is an infrequent complication. The lower incidence of epithelial ingrowth after femtosecond LASIK surgery compared with mechanical microkeratome-assisted LASIK may be attributed to the anatomy of the femtosecond laser-created side cut in contrast to that created with a mechanical microkeratome and the creation of less peripheral trauma at the time of flap creation.

Intacs implantation with sequential collagen cross-linking treatment in postoperative LASIK ectasia.

PURPOSE: To report the postoperative course and refractive results of each eye of a patient with postoperative LASIK ectasia for whom Intacs SK (severe keratoconus, Addition Technology Inc) implantation and collagen crosslinking (CXL) treatments were performed. METHODS: A 27-year-old man with postoperative LASIK ectasia with best spectacle-corrected visual acuity (BSCVA) of 20/60 and 20/80 in the right and left eyes, respectively, was operated for Intacs SK implantation for both eyes. Spherical equivalent refraction and mean keratometric values in the right and left eyes were -14.50 diopters (D) and -10.50 D and 56.20 D and 50.70 D, respectively. Following bilateral Intacs SK implantation, CXL was performed after 1 day in the left eye and 1 month in the right eye. RESULTS: During follow up, there was an improvement in visual acuity and decrease in manifest refraction and keratometric values in both eyes. A slight regression of these values was noted in the right eye 1 month after Intacs SK implantation, which was reversed by CXL. Eight months postoperatively, BSCVA was 20/25 and 20/25, manifest refractions were -1.50 x 170 and -1.25 x 50, and mean keratometric values were 47.20 and 44.20 D in the right and left eyes, respectively. CONCLUSIONS: Intacs SK implantation and subsequent CXL may be alternatived in the treatment of postoperative LASIK ectasia.

Intacs implantation using a femtosecond laser for management of keratoconus: Comparison of 306 cases in different stages.

PURPOSE: To evaluate the efficacy of intrastromal ring segment (Intacs, Addition Technology, Inc.) implantation and analyze outcomes according to different keratoconus stages. SETTING: Kudret Eye Hospital, Ankara, Turkey. METHOD: In this retrospective noncomparative case series, 306 keratoconic eyes of 255 patients who had Intacs segment implantation were reviewed. Patients were grouped according to the Amsler-Krumeich keratoconus classification (stage II, 155 eyes; stage III, 83 eyes; stage IV, 68 eyes). The uncorrected visual acuity (UCVA), best corrected visual acuity (BCVA), central corneal curvature, spherical and cylindrical manifest refractions, and central corneal thickness were analyzed and compared according to keratoconus stage. RESULTS: At a mean follow-up of 10.39 months +/- 5.04 (SD), the BCVA improved in 71.6% of eyes and the UCVA improved in 75.7% of eyes. The mean keratometry (K) decreased from 50.7 diopters (D) to 47.9 D (P<.05); the mean manifest spherical refraction, from -6.04 D to -3.09 D (P<.05); and the mean manifest cylindrical refraction, from -4.11 D to -3.82 D (P>.05). The changes in BCVA and manifest spherical and cylindrical refractions were not statistically different between the different keratoconus stages (P >.05). There was less change in UCVA and more improvement in the mean K value after Intacs treatment in stage IV than in the other stages (P<.05, analysis of variance). CONCLUSIONS: Intacs treatment with a femtosecond laser was effective for management of keratoconus of all stages. Improvement in UCVA may be less in severe keratoconus than in moderate keratoconus.

Clinicopathological parameters and expression of P-glycoprotein and MRP-1 in retinoblastoma.

PURPOSE: The immunohistochemical expressions of two multidrug resistance proteins, P-glycoprotein (P-gp) and multidrug resistance-related protein-1 (MRP-1), were studied in retinoblastoma and the correlations with the clinicopathological parameters were assessed. METHOD: Sixty-five enucleated eyes containing retinoblastoma were included in the study. Following hematoxylin-eosin staining, tumor differentiation, presence of choroidal invasion, optic nerve invasion, retinal invasion, necrosis and presence of calcification were evaluated with the light microscope. P-gp and MRP-1 expressions were evaluated immunohistochemically. RESULTS: Fifty-three eyes were enucleated primarily and 12 eyes were operated after failure of chemotherapy. P-gp and MRP-1 expressions were positive in 69.3 and 73.4% of specimens, respectively. There was no statistically significant relationship between the expressions of P-gp and MRP-1, and tumor differentiation, presence of tumor invasion or treatment with chemotherapy. CONCLUSION: Retinoblastoma intrinsically expresses both P-gp and MRP-1 and their expressions are not related to tumor differentiation. The expressions of P-gp and MRP-1 do not seem to be induced by chemotherapy and are not related to the degree of tumor invasion.

Comparison of outcomes of 2 channel sizes for intrastromal ring segment implantation with a femtosecond laser in eyes with keratoconus.

PURPOSE: To compare the outcomes of 2 channel sizes for intrastromal ring segment (Intacs, Addition Technology, Inc.) implantation using a femtosecond laser in eyes with keratoconus. SETTING: Kudret Eye Hospital, Ankara, Turkey. METHODS: A retrospective outpatient study included 159 consecutive keratoconic eyes of 103 patients. Patients were classified into 2 groups according to channel dissection size: wide (6.7 mm x 8.2 mm) and narrow (6.6 mm x 7.6 mm). Dissections were created with an IntraLase femtosecond laser (IntraLase Corp.). The 2 groups were compared according to uncorrected visual acuity (UCVA), best corrected visual acuity (BCVA), refractive error (manifest sphere, manifest cylinder, and manifest refractive spherical equivalent), mean K-value, and complications within 6 months postoperatively. RESULTS: The wide-channel group comprised 97 eyes of 65 patients (37 men, 28 women) with a mean age of 27.64 years +/- 8.61 (SD). The narrow-channel group comprised 62 eyes of 38 patients (23 men, 15 women) with a mean age of 26.62 +/- 6.13 years. At 6 months, the UCVA and BCVA had significantly improved in 63.9% and 70.1% of eyes, respectively, in the wide-channel group and in 72.5% and 75.8% of eyes, respectively, in the narrow-channel group. The change in mean BCVA and change in mean UCVA in both groups were not statistically significant (P<.05, independent samples t test). There was no between-group difference in the improvement in manifest spherical refraction, cylindrical refraction, manifest refractive spherical equivalent, or mean K-readings (P<.05, independent samples t test). Epithelial plug, yellow-white deposits, tunnel haze around segments, and upward movement of the inferior segment without extrusion were observed more frequently in the narrow-channel group than in the wide-channel group. CONCLUSIONS: The refractive outcomes of wide channels and narrow channels for Intacs treatment in eyes with keratoconus were similar 6 months postoperatively. The narrow-channel group had a higher rate of mild to moderate complications than the wide-channel group.

Analysis of centration of Intacs segments implanted with a femtosecond laser.

PURPOSE: To analyze the centration of intrastromal ring segments (Intacs, Addition Technology, Inc.) implanted using a femtosecond laser in eyes with keratoconus. SETTING: Kudret Eye Hospital, Ankara, Turkey. METHODS: In a retrospective noncomparative case series, the distance of deviation of the intrastromal ring segment from the pupillary center was evaluated in 59 eyes of 39 keratoconic patients after tunnel creation with a femtosecond laser. The distance of deviation of segments from the pupillary edge and direction of decentration were analyzed using the anterior segment analyzer of the Pentacam Scheimpflug photographic camera (Oculus Opticgerate GmbH). RESULTS: Intacs were successfully implanted in all eyes. The mean horizontal deviation was 788.33 microm +/- 500.34 (SD) (range 30 to 2450 microm), and there was a temporal displacement in all eyes. The mean vertical deviation was 370.83 +/- 343.17 microm (range 0 to 1690 microm), and there was an inferior displacement in 28.81% of eyes and superior displacement in 66.10% of eyes. There was no vertical displacement in 3 eyes (5.08%). CONCLUSION: During applanation for Intacs correction by a femtosecond laser, the cornea and pupil are not in their natural position, which leads to decentration and misalignment of the segments.

Implantation of Artisan toric phakic intraocular lens following Intacs in a patient with keratoconus.

We report a 24-year-old man with bilateral keratoconus in whom Intacs (Addition Technology, Inc.) were implanted in both eyes. The procedure was followed by Artisan toric phakic intraocular lens (Ophtec) implantation to correct the residual myopic and astigmatic refractive error.

Intacs insertion with the femtosecond laser for the management of keratoconus: one-year results.

PURPOSE: To assess the outcomes of intrastromal ring segment (Intacs, Addition Technology) implantation for keratoconus using the femtosecond laser. SETTING: Kudret Eye Hospital, Ankara, Turkey. METHODS: In a retrospective noncomparative case series, 118 eyes of 69 patients with keratoconus who had Intacs segments implanted with the femtosecond laser were evaluated. Preoperative and postoperative evaluations included slitlamp examination, uncorrected visual acuity (UCVA), best corrected visual acuity (BCVA), and mean keratometry values measured with the Pentacam Scheimpflug camera (Oculus Opticgerate GmbH). All parameters were assessed preoperatively and 1 year after Intacs implantation. RESULTS: Intacs were successfully implanted in all eyes. At the end of the first postoperative year, 81.3% of eyes had improved UCVA and 73.7% had improved BCVA. The mean keratometry decreased from 51.56 diopters (D) to 47.66 D, and the mean refractive spherical equivalent decreased from -7.57 D to -3.72 D. CONCLUSIONS: Intacs implantation with the femtosecond laser was safe and effective for the treatment of keratoconus. All parameters had improved by the 1-year follow-up.

Vertical placement of aphakic Artisan intraocular lens in a patient with traumatic localized aniridia.

We report a 50-year-old patient who had secondary implantation of an aphakic Artisan (Ophtec) intraocular lens (IOL) that was placed vertically in the anterior chamber. The patient had had a perforating injury to the cornea that required corneal wound repair, lensectomy, and anterior vitrectomy. Because of the localized traumatic aniridia, the Artisan IOL could not be placed horizontally. Three months after surgery, the best corrected visual acuity was 0.9 and there were no complications.

Plasma homocysteine, vitamin B12 and folate levels in age-related macular degeneration.

PURPOSE: The purpose of this study was to investigate the association of age-related macular degeneration (AMD) with plasma homocysteine, vitamin B12, and folate levels. METHODS: Sixty patients diagnosed with AMD at our clinic between March 2004 and September 2004 were assessed in a prospective cross-sectional study. Plasma homocysteine, vitamin B12, and folate levels taken after 8 h of fasting from 30 patients with exudative AMD and 30 patients with dry AMD were compared with the results of 30 age- and sex-matched healthy participants. RESULTS: Patients with both exudative and dry types of AMD had significantly higher plasma homocysteine levels (mean 14.19+/-3.11 micromol/l; 13.07+/-2.90 micromol/l respectively) compared with the controls (mean 10.79+/-2.56 micromol/l; (p=0.000 and p=0.008 respectively). Homocysteine levels were higher in the exudative AMD group compared with the dry AMD group, but the difference was not statistically significant (p=0.290). Plasma vitamin B12 levels were found to be significantly lower in the exudative AMD group (289.14+/-113.44 pg/l) compared with the controls (436.17+/-204.12 pg/l) and dry AMD group (443.47+/-190.83 pg/l; (p=0.000). Plasma folate levels were comparable among groups (p=0.106). CONCLUSION: This study suggests an association between elevated plasma homocysteine and AMD regardless of the subtype. Further controlled prospective studies are needed to investigate the possible role of homocysteine in AMD and the effect of vitamin B12 and folate supplementation in this process.