Nayyirih G. Tahzib

Use of Anterior Segment Optical Coherence Tomography to Study Corneal Changes After Collagen Cross-linking

PURPOSE To investigate the stromal demarcation line after corneal cross-linking using anterior segment optical coherence tomography (AS-OCT) and its influence on the short-term results of cross-linking in patients with progressive keratoconus. DESIGN Prospective, nonrandomized study. METHODS Twenty-nine eyes of 29 patients with progressive keratoconus (n = 28) or after laser in situ keratomileusis ectasia (n = 1) were included and treated with corneal cross-linking at our institution. Measurements at 1, 3, 6, and 12 months after corneal cross-linking were: refraction, best-corrected visual acuity (BCVA), tonometry, corneal topography, AS-OCT, specular microscopy, and aberrometry. Demarcation line depth was measured centrally, 2 mm temporally, and 2 mm nasally by two independent observers using AS-OCT and was correlated with clinical parameters. RESULTS The stromal demarcation line was visible with AS-OCT at 1 month after surgery in 28 of 29 eyes. Pairwise comparisons between the two observers of the AS-OCT measurements did not show a statistically significant difference. After an initial steepening of maximal keratometry values and a decrease in BCVA at 1 month after surgery (both with P < .012), no significant changes were found at 3, 6, and 12 months after surgery compared with before surgery. Refractive cylinder, topographic astigmatism, aberration values, endothelial cell density, and intraocular pressure remained stable during all postoperative visits. A deeper demarcation line depth was associated with a larger decrease in corneal thickness (r = -0.506; P = .012). CONCLUSIONS AS-OCT is a useful device to detect the stromal demarcation line after corneal cross-linking. At 3 to 12 months follow-up, all clinical parameters remained stable, indicating stabilization of the keratoconic disease.

Efficacy and safety of femtosecond laser-assisted corneal endothelial keratoplasty: a randomized multicenter clinical trial.

Background. To evaluate the efficacy and safety of femtosecond laser-assisted endothelial keratoplasty (FLEK) versus penetrating keratoplasty (PK) in patients with corneal endothelial disease. Methods. A randomized multicenter clinical trial of 80 eyes of 80 patients with corneal endothelial disease were randomized to FLEK or PK. Clinical outcomes (astigmatism and visual acuity) and incidence of postoperative complications were compared between the two groups. Results. At 12 months, the percentage of eyes with a refractive astigmatism less than or equal to 3 diopters was higher in the FLEK group in comparison with the PK group (86.2% vs. 51.3%, P=0.004). The mean postoperative best corrected visual acuity was 20/70±2 lines in the FLEK group and 20/44±2 lines in the PK group (P<0.001), but the gain in the best corrected visual acuity between the two groups was not significantly different. The endothelial cell loss in the FLEK and PK group was 65±12% and 23±15% (P<0.001). The most common postoperative complication in the FLEK group was graft dislocation (27.8%). Wound healing related problems occurred in six eyes (15%) in the PK group and in none of the FLEK eyes. Conclusions. FLEK effectively reduces postoperative astigmatism and results in an absence of wound healing related problems in patients with endothelial disease. However, visual acuity is lower as compared with conventional PK, and the high level of endothelial cell loss warrants a modification of the insertion technique of the endothelial graft.

Intraocular straylight after implantation of the multifocal AcrySof ReSTOR SA60D3 diffractive intraocular lens.

PURPOSE: To measure intraocular straylight (as a measure of glare) after cataract surgery and implantation of an AcrySof ReSTOR SA60D3 multifocal or AcrySof SA60AT monofocal intraocular lens (IOL) (both Alcon Laboratories). SETTING: University Hospital Maastricht, Maastricht; Isala Clinics, Zwolle; Netherlands Institute for Neurosciences, Amsterdam, The Netherlands. METHODS: In a prospective open observational case series, a newly developed straylight meter was used to objectively measure straylight 6 months postoperatively in 66 eyes with a diffractive AcrySof ReSTOR SA60D3 IOL (multifocal group) and 40 eyes with a monofocal AcrySof SA60AT IOL (monofocal group). A comparison of straylight levels in an age‐matched population without cataract (control group) was performed. RESULTS: The straylight level was 1.20 log units ± 0.16 (SD) in the multifocal group and 1.10 ± 0.19 log units in the monofocal group. When the difference in mean level of straylight was adjusted for age, mean straylight levels were 0.078 log units lower in the monofocal group than in the multifocal group (P = .026). Straylight levels in both pseudophakic groups were lower than in the control group without cataract (P<.0001). CONCLUSIONS: Levels of intraocular straylight log(s) were significantly lower for both types of IOL than in age‐matched subjects from the normal population. The mean level of intraocular straylight 6 months postoperatively was higher in patients with an AcrySof ReSTOR SA60D3 IOL than in patients with a monofocal AcrySof SA60AT IOL. Implantation of the former IOL would therefore result in a smaller gain in contrast sensitivity and a smaller reduction in glare and halos than implantation of the latter IOL.

Functional outcomes and patient satisfaction after laser in situ keratomileusis for correction of myopia

PURPOSE: To determine subjective patient satisfaction and self‐perceived quality of vision after laser in situ keratomileusis (LASIK) to correct myopia and myopic astigmatism. SETTING: Department of Ophthalmology, Academic Hospital Maastricht, Maastricht, The Netherlands. METHODS: A validated questionnaire consisting of 66 items was self‐administered by 142 consecutive patients. Seven scales covering a specific aspect of quality of vision were formulated. Aspects included global satisfaction, quality of uncorrected and corrected vision, quality of night vision, glare, daytime driving, and night driving. Main outcome measures were responses to individual questions and scale scores, and correlations with clinical parameters including refractive outcome, uncorrected visual acuity, best corrected visual acuity, ablation depth, and scotopic pupil–optical zone disparity were obtained. RESULTS: The mean score for the overall satisfaction was 4.1 ± 0.71 (SD) (scale 0 to 5.0). A total of 92.2% of patients were satisfied or very satisfied with their surgery, 93.6% considered their main goal of surgery achieved, and 92.3% would choose to have LASIK surgery again. Satisfaction with uncorrected vision was 3.03 ± 0.71. The mean score for glare was 3.0 ± 0.9. At night, glare from lights was believed to be more important than before surgery by 47.2%. Glare from oncoming car headlights after surgery was reported by 58.4% and was believed to be more bothersome for night driving than before surgery by 52.8%. Night driving was rated more difficult than before surgery by 39.4%, whereas 59.3% had less difficulty driving at night. There was a significant correlation between the uncorrected vision score and the postoperative spherical equivalent (r = 0.245) and postoperative astigmatism (r = 0.265). There was no correlation between the glare or night vision scores and the degree of correction, the amount of ablation depth, or the disparity between the scotopic pupil and the optical zone. CONCLUSIONS: Self‐perceived uncorrected vision after LASIK surgery for the correction of myopia and myopic astigmatism appears to be very good and is related to the postoperative residual error. Although the majority of patients postoperatively experienced glare, particularly with driving at night, this was not related to the pupil‐optical zone disparity or degree of correction.

Femtosecond laser-assisted inverted mushroom keratoplasty.

PURPOSE To evaluate best-corrected visual acuity (BCVA), refractive outcome, corneal topography, optical coherence tomography, and endothelial cell density 12 months after femtosecond laser-assisted inverted mushroom keratoplasty. METHODS We performed a prospective study of a surgical case series of 5 patients undergoing femtosecond laser-assisted inverted mushroom keratoplasty for pseudophakic bullous keratopathy or pre-Descemet X-linked ichthyosis. The femtosecond laser was used to create a top-hat configuration in the donor cornea and recipient cornea. Laser parameters were as follows: energy, 4.0 (anterior inner vertical side cut and horizontal lamellar cut) and 7.0 microJ (posterior outer vertical side cut); spiral pattern with a firing rate of 15 kHz. The size of the anterior inner diameter was 7.4 mm in the donor cornea and 7.0 mm in the recipient cornea. The posterior outer diameter was 9.0 mm in all eyes. RESULTS At 6 and 12 months after surgery, all corneal grafts were clear and showed an excellent adaptation of the lamellar donor and recipient wound surfaces. At 12 months postoperatively, BCVA averaged 20/32 (range, 20/60-20/20), refractive cylinder averaged -3.20 +/- 2.0 D, topographical cylinder averaged 3.26 +/- 2.1 D, and the mean endothelial cell density was 1793 +/- 491 cells/mm2 (range, 954-2237 cells/mm2). The mean central corneal thickness and thickness of the posterior shelf was 517 +/- 3 and 175 +/- 8 microm, respectively. CONCLUSIONS The femtosecond laser-assisted inverted mushroom keratoplasty shows good promise in surgical treatment of corneal diseases. The multiplanar fit between the donor and recipient cornea allows early suture removal and visual rehabilitation.

Higher-order aberrations after implantation of iris-fixated rigid or foldable phakic intraocular lenses

PURPOSE: To evaluate higher‐order aberrations (HOAs) after implantation of Artiflex phakic intraocular lenses (pIOLs). SETTING: Department of Ophthalmology, Academic Hospital Maastricht, Maastricht, The Netherlands. METHODS: This retrospective comparative case series comprised 27 eyes (14 patients) that had Artiflex pIOL implantation and 22 eyes (13 patients) that had Artisan pIOL implantation. Refractive data, pupil size, IOL decentration, and HOA values were recorded and compared. Laboratory analysis was performed. Follow‐up was 1 year. RESULTS: In the Artiflex group, the mean spherical equivalent (SE) changed from −9.95 diopters (D) ± 1.43 (SD) (range −6.75 to −12.13 D) to −0.30 ± 0.53 D (range −1.94 to 0.56 D). Postoperatively, trefoil‐y increased (increase factor 1.73) and spherical aberration decreased (increase factor 0.55). The mean pIOL decentration was 0.24 ± 0.12 mm; 96.3% were decentered 0.5 mm or less. There was a significant correlation between pIOL decentration and postoperative spherical aberration and coma‐y. In the Artisan group, the mean SE changed from −9.90 ± 2.74 D (range −4.00 to −14.50 D) to −0.20 ± 0.42 D (range −0.75 to 0.50 D). Postoperatively, trefoil‐y and spherical aberration increased (increase factors 3.32 and 6.84, respectively). Laboratory analysis confirmed the negative and positive spherical aberration profile of the Artiflex pIOL and Artisan pIOL, respectively. CONCLUSIONS: Artiflex pIOL implantation decreased spherical aberration, while Artisan pIOL implantation increased spherical aberration. Trefoil‐y increased in both groups. These changes might be explained by incision size differences in relation to trefoil and differences in optic design in relation to spherical aberration.

Corneal cross-linking for treatment of progressive keratoconus in various age groups.

PURPOSE To compare the effect of corneal cross-linking (CXL) for keratoconus in various age groups and to investigate the influence of the topographic cone location on the outcome of CXL. METHODS This cohort study included 95 patients (119 eyes) diagnosed as having progressive keratoconus who underwent epithelium-off standard protocol CXL from January 2010 through May 2012. For statistical analysis, patients were divided into three age groups: pediatric patients (< 18 years), adolescent patients (18 to 26 years), and adults (> 26 years). Visual acuity and refraction, topography, intraocular pressure, and endothelial cell counts were recorded preoperatively and postoperatively. RESULTS Topographic cones were located more centrally in pediatric corneas (0.85 ± 0.66 mm) compared to adolescent corneas (1.49 ± 0.76 mm, P = .002) and adult corneas (1.86 ± 0.99 mm, P < .001). Pediatric corneas flattened 1 year after CXL by a mean of 1.8 diopters (D), compared to 1.1 D in the other age groups. Central cones (0 to 1 mm) were steeper (62.3 ± 8.3 D) before treatment than peripheral cones (3 to 4 mm) (55.9 ± 8.9 D). One year after CXL, corrected distance visual acuity improved in all age groups, with the highest improvement in pediatric eyes (-0.23 ± 0.40 logMAR, P = .044). CONCLUSIONS Before CXL, cones of pediatric keratoconic corneas were located more centrally than in the two older age groups. After CXL, pediatric corneas showed more corneal flattening and more corrected distance visual acuity improvement. Pediatric CXL was equally safe compared to adolescent and adult CXL.

Anterior Chamber Depth Is Significantly Decreased after Scleral Buckling Surgery

OBJECTIVE Myopic patients have an increased risk for the development of a rhegmatogenous retinal detachment (RRD). Currently, myopic patients have the choice to undergo correction of their refractive error by the implantation of a phakic intraocular lens (pIOL). After pIOL implantation, progressive endothelial cell loss may result if the anterior chamber is too shallow. Because scleral buckling (SB) surgery for treatment of an RRD may in itself result in a decreased anterior chamber depth (ACD), this may become an important issue not only for the retinal surgeon who is faced with a patient who has both an RRD and a pIOL, but also for the refractive surgeon who should consider the potential problems of the implantation of pIOL in an eye that has previously undergone SB surgery. The goal of this study was to evaluate how long changes in ACD persist after SB procedures in patients with RRD. DESIGN Prospective case series. PARTICIPANTS Thirty-eight eyes with a primary RRD treated by SB using an encircling element and a radial or segmental buckle; 31 fellow eyes served as controls. METHODS Anterior chamber depth (in the horizontal meridian) and axial length were measured preoperatively and at 1 week and 1, 3, 6, 9, and 12 months postoperatively with an anterior optical coherence tomography method and an IOLMaster (Carl Zeiss Meditec, Jena, Germany), respectively. MAIN OUTCOME MEASURES In all 38 eyes, ACD was significantly reduced compared with preoperative levels up to 9 months after SB surgery. RESULTS Anterior chamber depth returned to normal at 1 year after surgery. Axial length was significantly enlarged during the whole follow-up period. No significant differences were found between the use of radial or segmental buckles. CONCLUSIONS Anterior chamber depth may remain decreased after SB for a longer time period than previously reported. FINANCIAL DISCLOSURE(S) The authors have no proprietary or commercial interest in any materials discussed in this article.

Results of cataract surgery after implantation of an iris-fixated phakic intraocular lens.

PURPOSE: To report the results of cataract surgery after previous implantation of an Artisan iris‐fixated phakic intraocular lens (pIOL) for the correction of myopia. SETTING: University center and private practice. METHODS: This study comprised eyes with previous implantation of an iris‐fixated pIOL to correct myopia and subsequent pIOL explantation combined with cataract surgery and in‐the‐bag implantation of a posterior chamber IOL. Predictability of refractive results, changes in endothelial cell density (ECD), and postoperative best corrected visual acuity (BCVA) were analyzed. RESULTS: The mean follow‐up after cataract surgery in the 36 eyes of 27 consecutive patients was 5.7 months ± 7.5 (SD). The mean time between pIOL implantation and cataract surgery was 5.0 ± 3.4 years. After explantation of the pIOL and subsequent cataract surgery, the mean spherical equivalent (SE) was −0.28 ± 1.11 diopters (D); the SE was within ±1.00 D of the intended correction in 72.2% of patients and within ±2.00 D in 86.1% of patients. The mean endothelial cell loss after the combined procedure was 3.5% ± 13.2% and the mean postoperative BCVA, 0.17 ± 0.18 logMAR. CONCLUSIONS: In patients with a history of implantation of an iris‐claw pIOL for the correction of myopia, cataract surgery combined with explantation of the pIOL yielded acceptable predictability of the postoperative SE and minimal loss of ECD, resulting in a gain in BCVA.

Corneal Crosslinking for Progressive Keratoconus in Four Children

The authors describe four children with progressive keratoconus treated by corneal crosslinking (CXL). The current CXL guidelines recommend treatment of patients 18 years and older. Nevertheless, keratoconus can rapidly progress in young teenagers. CXL could be a safe procedure to prevent a keratoplasty at a young age.