Fred A.G.J. Eggink

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.

Wavefront-guided versus standard laser in situ keratomileusis to correct low to moderate myopia

Purpose: To evaluate the 6‐month refractive outcomes of wavefront‐guided laser in situ keratomileusis (LASIK) (Zyoptix, Bausch & Lomb) versus standard LASIK (PlanoScan, Bausch & Lomb). Setting: Department of Ophthalmology, University Hospital Maastricht, Maastricht, The Netherlands. Methods: In a prospective randomized study, 12 patients with myopia had Zyoptix wavefront‐guided LASIK in 1 eye and PlanoScan LASIK in the contralateral eye. The safety, efficacy, predictability, stability, optical zone size, and ablation depth were evaluated. Results: The mean preoperative spherical equivalent (SE) of the subjective manifest refraction was −3.88 diopters (D) ± 1.92 (SD) (Zyoptix) and −4.35 ± 2.11 D (PlanoScan). Six months postoperatively, 8% of PlanoScan patients and 16% of Zyoptix patients gained at least 2 lines of best corrected visual acuity; the safety index was 1.12 in the Zyoptix group and 1.08 in the PlanoScan group. An SE of ±1.00 D and ±0.50 D was achieved by 100% and 92%, respectively, in both groups. There were 2 undercorrections in the Zyoptix group and 1 undercorrection in the PlanoScan group. In the Zyoptix group, 100% had a UCVA of 20/40 and 67% of 20/20 and in the PlanoScan group, 100% and 83%, respectively. The efficacy index was 0.87 and 0.93 in the Zyoptix group and PlanoScan group, respectively. The mean optical zone 6 months postoperatively was 6.16 ± 0.34 mm in the PlanoScan group and 6.23 ± 0.41 mm in the Zyoptix group (P = .67). The ablation depth per diopter of defocus equivalent was 13.5 ± 4.6 &mgr;m/D and 8.6 ± 4.4 &mgr;m/D, respectively (P = .01). Conclusions: An excellent safety index was achieved with the Zyoptix and PlanoScan treatments. The efficacy index was marginally lower for Zyoptix treatments as a result of 2 undercorrections. The ablation depth in the Zyoptix group per diopter of defocus equivalent was significantly lower than in the PlanoScan group. Further refinements in defining the ablation algorithms may increase the efficacy index.

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.

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.

Contact lens fitting in a patient with keratectasia after laser in situ keratomileusis

We present a case of unilateral iatrogenic keratectasia developing 15 months after bilateral laser in situ keratomileusis using a broad-beam excimer laser (Bausch & Lomb Keracor 116) to treat -3.5 -1.5 x 85 diopters of myopia. Preoperative pachymetry in the eye measured 450 microm without topographical changes suggesting keratoconus or forme fruste keratoconus. Contact lens fitting to provide 20/25 visual acuity is described.

Postoperative management and follow-up after corneal flap loss following laser in situ keratomileusis.

We present 3 cases of flap loss within 2 weeks of unilateral laser in situ keratomileusis. In all patients, spontaneous regeneration of the epithelial layer, covering the ablated stroma, was expected. In 2 patients, the best spectacle-corrected visual acuity recovered to 20/25 within 6 months and in 1 patient, a contact lens was fitted 6 months after the accident, restoring visual acuity to 20/25. The 6-month follow-up and the contact lens fitting technique are described.

Enlargement of the photorefractive keratectomy optical zone

Purpose: To evaluate the safety and efficacy of a photorefractive keratectomy (PRK) re‐treatment procedure that enlarges the optical zone and treats undercorrection. Setting: Rotterdam Eye Hospital and Medisch Centrum Alkmaar, The Netherlands. Methods: This study evaluated 16 eyes that had PRK for myopia with the Summit excimer laser that resulted in a mean undercorrection of −2.82 diopters (D). Patients also reported impaired night vision including difficulty in driving, halos, and stray light and ghost images. These phenomena persisted after spectacle correction of residual refractive error, necessitating further treatment with a larger ablation zone. With a VISX 20/20 excimer laser, the optical zone was enlarged to 6.0 mm and undercorrection treated with a 6.0 mm ablation. Results: At 13.5 months after re‐treatment, mean reduction in myopia was 1.70 D, resulting in a residual undercorrection of −1.08 D. In seven eyes, final refraction was within 1.00 D of emmetropia. Only two patients continued to report nightdriving problems. Conclusions: Re‐treating undercorrections combined with enlarging the ablation zone resulted in a reduction in myopia from a mean of 2.82 to 1.08 D. Subjective reports of halos and stray light images were decreased in all cases.

Late-onset decentration of iris-fixated phakic intraocular lenses: a case series.

PURPOSE To investigate late-onset downward decentration of iris-fixated phakic intraocular lenses (pIOL) resulting from progressive shifting of the haptics through the iris and its influence on the position of the pIOL and the amount of enclavated iris tissue. DESIGN Institutional, prospective, observational case series. METHODS Six patients (9 eyes) from among 368 eyes had 1 shifted haptic during long-term follow-up. Anterior segment optical coherence tomography (AS-OCT) was used to measure the distance between the edges of the pIOL and the corneal endothelium. Slit-lamp photography imaged the pIOL after implantation and after decentration. The images were analyzed to determine decentration and amount of iris tissue at the enclavation sites. RESULTS Shifting of the haptics occurred in 2.4% and was discovered at a mean follow-up of 4.8 years (range, 3 to 7 years). Mean downward decentration was 0.28 +/- 0.15 mm. Mean edge-distances on the nasal, temporal, superior, and inferior side were 1.71 +/- 0.30 mm, 1.86 +/- 0.31 mm, 1.86 +/- 0.31 mm, and 1.58 +/- 0.34 mm, respectively. Mean enclavated iris tissue on the nasal and temporal side was smaller after decentration when compared with that directly after surgery (P = .033 and P = .017, respectively). Shifting of the haptics did not result in a decreased uncorrected and best-corrected visual acuity. CONCLUSIONS Late-onset downward decentration resulting from progressive shifting of the haptics occurred in 2.4% and was associated with a decrease in enclavated iris tissue. AS-OCT showed a mean distance between the edge of the pIOL and the endothelium greater than the advised safety distance of 1.5 mm.

Evaluation of pupil dynamics after implantation of artisan phakic intraocular lenses.

PURPOSE To compare pre- and postoperative horizontal and vertical pupil diameters after horizontal Artisan phakic intraocular lens (PIOL) (Ophtec BV, Groningen, The Netherlands) implantation for correction of myopia. METHODS The pre- and postoperative scotopic pupil diameters measured by the Colvard pupillometer (Oasis Medical, Glendora, Calif) were compared in 71 eyes after Artisan PIOL implantation (Artisan Colvard group). Analysis of pupil shape (vertical vs horizontal diameter, V/H ratio) after horizontal Artisan PIOL implantation was performed with the Procyon pupillometer (Procyon Instruments Ltd, London, United Kingdom) in 121 eyes (Artisan Procyon group) under scotopic, mesopic-low, and mesopic-high conditions and compared to an age- and refraction-matched control group of 121 eyes of refractive surgery candidates (Procyon control group). RESULTS After horizontal Artisan PIOL implantation, the mean horizontal pupil diameter decreased from 6.231 +/- 0.70 mm preoperatively to 5.34 +/- 0.68 mm postoperatively in the Artisan Colvard group (P < .01). The mean horizontal scotopic diameter was 5.60 +/- 0.66 mm, the mesopic-low diameter was 4.94 +/- 0.71 mm, and the mesopic-high diameter was 3.98 +/- 0.54 mm for the Artisan Procyon group. The mean horizontal scotopic diameter was 6.29 +/- 0.91 mm, the mesopic-low diameter was 5.40 +/- 0.96 mm, and the mesopic-high diameter was 4.16 +/- 0.80 mm in the Procyon control group. A significant increase was noted in V/H ratio under scotopic, mesopic-low, and mesopic-high conditions from 1.02, 1.02, and 1.01, respectively, in the Procyon control group to 1.17, 1.12, and 1.06, respectively, in the Artisan Procyon group (P < .01). CONCLUSIONS Horizontal pupil size was significantly decreased after horizontal Artisan PIOL implantation and might be attributed to a mechanical restriction of the iris in the horizontal meridian.

Recovery of the visual acuity in a family with Reis–Bückler dystrophy

BACKGROUND The hereditary Reis-Bückler dystrophy is one of the anterior localised corneal dystrophies with superficial reticulated opacities, sometimes in combination with recurrent attacks of corneal erosion. Phototherapeutic keratectomy (PTK) is now the first method to consider for managing this disease when intervention is required. METHODS We treated six eyes of four related patients with Reis-Bückler dystrophy, who had a demonstrable reduction in visual acuity due to corneal opacities within their virgin corneas (three eyes), penetrating (one eye) or lamellar (two eyes) grafts. We present the results of change in visual acuity and best corrected spherical spectacle and contact lens refraction at 1 year following surgery. In one case, we had to fit a rigid contact lens to correct the hyperopic shift which caused anisometropia. RESULTS The mean spherical refractive change 1 year after PTK surgery was 0.33+/-S.D., 1.8D. A hyperopic shift was observed in four eyes. Visual acuity remained stable in all patients 1 year after surgery. The central corneal area remained clear, and mean best spectacle corrected visual acuity improved from +0.8 logMAR before PTK to +0.15 logMAR after 1 year. There was no significant change (P>0.8) between the mean 1 year best spectacle corrected visual acuity (+0.125 log MAR +/- S.D. 0.15) and the best contact lens corrected visual acuity (+0.108 log MAR +/- S.D. 0.16). After fitting a contact lens in one patient to correct anisometropia, the hyperopic shift did not change significantly during 12 months of follow-up. It was not necessary to adjust the lens parameters. One patient required cataract surgery. CONCLUSION PTK corneal surgery is the treatment of first choice when intervention is required in patients with Reis-Bückler dystrophy because it is safe and much less invasive than lamellar or penetrating keratoplasty. Contact lens fitting following PTK has not changed corneal shape.