Yoshiko Hori-Komai

Epithelial ingrowth after laser in situ keratomileusis: Clinical features and possible mechanisms

PURPOSE To analyze the incidence, clinical course, and possible mechanisms of epithelial ingrowth after laser in situ keratomileusis (LASIK). DESIGN Interventional case series. METHODS Retrospective evaluation of 4,867 eyes of 2,502 patients who had LASIK. The type of microkeratome (LSK-One or MK-2000), corneal flap thickness, and clinical course were analyzed. We also compared the cutting characteristics of both microkeratomes in pig cadaver eyes by scanning electron microscopy. RESULTS The frequency of epithelial ingrowth was significantly greater in the MK-2000 (34 of 1,680 eyes; 2.0%) than the LSK-One group (30 of 3,187 eyes; 0.94%; P =.001). In 24 eyes (37.5%), blood, cell infiltration, ointment under the corneal flaps, or epithelial defect were detected at the area of epithelial ingrowth postoperatively. The incidence of epithelial ingrowth was correlated with the incidence of epithelial defect during surgery (P <.001) and with incidence of diffuse lamellar keratitis after surgery (P =.003). Flap thickness was thinner in eyes with epithelial ingrowth (126.0 +/- 29.1 microm) compared with flap thickness in eyes without epithelial ingrowth (133.8 +/- 27.3 microm; P <.001). Scanning electron microscopy showed clear differences in the appearance of flap edges created by the two types of microkeratomes. Epithelial ingrowth disappeared or remained unchanged in 54 eyes (90%) and progressed in six cases (10%). CONCLUSIONS Poor adhesion caused by excessive hydration due to epithelial defect as well as by foreign bodies between the flap stromal bed and thickness and morphologic characters of the corneal flap, depending on the type of microkeratomes, are related factors for development of epithelial ingrowth.

Comparison of LASIK using the NIDEK EC-5000 optimized aspheric transition zone (OATz) and conventional ablation profile.

PURPOSE To compare a new ablation algorithm termed the optimized aspheric transition zone (OATz) with the conventional laser ablation profile for correction of myopic astigmatism. METHODS LASIK using OATz profile #6 or using conventional ablation profile was performed on 98 eyes of 53 patients (OATz #6 group) and 111 eyes of 66 patients (control #6 group), respectively. Further, LASIK using OATz profile #5 or using the conventional ablation profile was performed on 109 eyes of 58 patients (OATz #5 group) and 109 eyes of 75 patients (control #5 group), respectively. The effective optical zone, uncorrected visual acuity, manifest refraction, aberrations, contrast sensitivity, and patient satisfaction at 3 months postoperatively were compared between the OATz #6 and control #6 groups and between the OATz #5 and control #5 groups. RESULTS The effective optical zones in the OATz #6 group (6.45 +/- 0.29 mm) or OATz #5 group (6.40 +/- 0.21 mm) were significantly larger than those in the control #6 group (6.33 +/- 0.27 mm) or control #5 group (6.26 +/- 0.25 mm) (P < .01), respectively. Uncorrected visual acuity and manifest refraction were similar in all groups. The changes in contrast sensitivity were significant and favored the OATz #6 (P < .01) and OATz #5 groups (P < .05). The patient satisfaction survey found no statistical difference at 3 months postoperatively. CONCLUSIONS Patients treated with the OATz profiles had better visual quality as measured by contrast sensitivity and also had larger effective optical zones as compared with those treated by the conventional ablation profile.

Reasons for not performing refractive surgery.

Purpose: To analyze the reasons that laser in situ keratomileusis (LASIK) or photorefractive keratectomy (PRK) were not performed in patients who requested surgical correction of their refractive errors. Setting: Minamiaoyama Eye Clinic, Tokyo, Japan. Methods: This retrospective review comprised 2784 consecutive patients who visited our clinic between June 1997 and August 2000. The reasons they did not receive refractive surgery (PRK or LASIK) were analyzed. Results: Among the 2784 patients who requested surgery for refractive errors, 2079 patients (74.7%) had PRK or LASIK and 705 patients (25.3%) did not. The most common reasons for not treating patients surgically were myopia greater than −12.0 diopters and/or high astigmatism (20.7%), insufficient corneal thickness (8.2%), keratoconus (6.4%), cataract (5.7%), and hyperopia and/or hyperopic astigmatism (4.1%). Conclusions: Patients who request surgery have a variety of problems. Attention must be given to these individual problems, and the indications must be considered.

Detection of cyclotorsional rotation during excimer laser ablation in LASIK

PURPOSE Positionally induced cyclotorsion could be an important factor in the correction of astigmatism during refractive surgery. We analyzed the change in cyclotorsional rotation during excimer laser ablation in LASIK surgery using the NIDEK Torsion Error Detector (TED). METHODS One hundred ten patients (192 eyes) who underwent LASIK for myopic astigmatism, using the NIDEK Advanced Vision Excimer Laser (NAVEX) were measured for cyclotorsion during surgery using the TED system. The manifest refraction of these patients was -6.80+/-2.74 diopters (D) (range: -1.00 to -13.75 D). The iris pattern of the patients eyes in the supine position was recorded via a CCD camera in the EC5000CXII excimer laser system, and it was compared to the iris pattern acquired during OPD-Scan measurement in the sitting position. RESULTS During laser ablation, the degree of cyclotorsional rotation detected by TED was 1.33+/-1.88 degrees (range: -6.33 to 2.99 degrees) clockwise and 1.00+/-1.79 degrees (range: -3.70 to 7.34 degrees) counterclockwise. The absolute degree of torsion error detected by the TED system was 2.33+/-1.16 degrees (range: 0 to 6.21 degrees). CONCLUSIONS The effectiveness of the cylinder treatment can be reduced due to torsion errors. The degree of cyclotorsion constantly changes during laser ablation. Therefore, a monitoring system should be developed for the measurement of torsion error, and this will enable the maximum possible correction of the error during laser ablation.

Ocular surface treatment before laser in situ keratomileusis in patients with severe dry eye.

PURPOSE To evaluate the efficacy and safety of laser in situ keratomileusis (LASIK) in patients with severe dry eye associated with Sjögrens syndrome. METHODS Three patients (six eyes) with Sjögrens syndrome who underwent bilateral LASIK were retrospectively evaluated for visual outcome, intraoperative and postoperative complications, dry eye status (subjective symptoms and objective findings, Schirmer test, vital staining of the ocular surface), and outcome satisfaction by subjective questionnaire. All patients had negative reflex tearing and were treated with topical autologous serum and/or punctal occlusion prior to LASIK to improve the ocular surface. This treatment was continued postoperatively. RESULTS Mean attempted correction of six eyes was -8.46 +/- 1.55 D (range -7.00 to -10.63 D). One year after LASIK, mean uncorrected visual acuity was 1.07 (range 0.7 to 1.5), mean best spectacle-corrected visual acuity was 1.29 (range 1.2 to 1.5), and mean refraction was -0.19 +/- 0.51 D (range -1.00 to +0.50 D). Tear production, rose bengal and fluorescein staining, and dry eye symptoms were not exacerbated after LASIK. No complications, such as intraoperative epithelial defect, diffuse lamellar keratitis, epithelial ingrowth, or recurrent erosion occurred. All three patients were satisfied with the outcome of their surgery. CONCLUSION LASIK can be safely and effectively managed in patients with severe dry eye with reduced reflex tearing by preoperative and postoperative treatments consisting of a combination of artificial tears, topical autologous serum, and punctal occlusion. Careful assessment of preoperative and postoperative ocular surface status is mandatory in such patients.

Experience with the Artisan phakic intraocular lens in Asian eyes

Purpose: To investigate the efficacy and safety of implantation of an iris‐claw phakic intraocular lens (PIOL), Artisan Myopia, in Asian eyes. Setting: Minamiaoyama Eye Clinic, Tokyo, Japan. Methods: Forty‐four eyes of 32 Japanese patients and 1 Korean patient with high myopia had Artisan Myopia lens implantation to correct their refractive errors. Lens models, 5/8.5 or 6/8.5 (optic diameter/overall diameter), were chosen as standard lens model. A smaller lens model (5/7.5‐Artisan Myopia Small) was implanted in eyes with corneal diameter less than 11.0 mm. Postoperative examinations were performed on 1 day, 1 week, 1 month, 3 months, 6 months, 1 year, and 2 years after surgery. Uncorrected visual acuity (UCVA), best corrected visual acuity (BCVA), manifest refraction, corneal endothelial cell counts, intraocular pressure, and complications were evaluated. Results: Artisan Myopia Small lenses were implanted in 4 eyes (9.1%) and 8.5 mm diameter lenses were implanted in 40 eyes. Preoperative UCVA (logMAR) improved from 1.57 to 0.09 at 1 month after surgery and no regression was observed thereafter. Postoperative manifest refraction was −1.02 ± 0.87 D (−3.25 to −0.00 D), and within 1.0 D in 20 eyes (55.6%), within 2.0 D in 32 eyes (88.9%) at 1 month after surgery, and stable during the follow‐up period. The final BCVA decreased 2 lines in 2 eyes (4.5%) due to progression of age‐related cataract. No serious complications such as angle closure or progressive endothelial cell loss were observed. Conclusion: Implantation of an Artisan iris‐claw PIOL implantation may be a safe and effective procedure for Asian eyes.

Infectious keratitis outbreak after laser in situ keratomileusis at a single laser center in Japan

PURPOSE: To evaluate an outbreak of infectious keratitis after laser in situ keratomileusis (LASIK) at a single laser center in Japan. SETTING: Tokyo Dental College, Chiba, Japan. DESIGN: Case series. METHODS: Relevant demographic and clinical data were obtained from case records using a standardized multicenter questionnaire at 12 major hospitals. The clinical manifestations, management, and outcomes were analyzed. RESULTS: Thirty‐nine eyes of 30 patients developed infectious keratitis after LASIK at the specified clinic. Cases of infection continued to appear over a 5‐month period. The most common interval between LASIK and the onset of infection was within 2 weeks (36 eyes, 92.3%). Slitlamp manifestation included granular opacity beneath flap (71.8%), multiple infiltration (66.7%), and epithelial defect (30.8%). Mycobacterium was identified as the causative organism in 9 eyes (23.1%). In most cases, topical amikacin, arbekacin, and erythromycin in addition to fourth‐generation fluoroquinolones were effective. Flap amputation was necessary in 10 eyes (25.6%) of 10 patients. Decimal visual acuity at initial presentation was worse than 0.10 in 14 eyes (35.9%), 0.15 to 0.50 in 8 eyes (20.5%), and 0.60 to 0.90 in 7 eyes (17.9%) and was better than 1.00 in 10 eyes (25.6%). Final decimal visual acuity was worse than 0.10 in 2 eyes (5.1%), 0.15 to 0.50 in 5 eyes (12.8%), and 0.60 to 0.90 in 11 eyes (28.2%) and was better than 1.00 in 21 eyes (53.8%). CONCLUSIONS: Mycobacterium was identified as the causative organism of this outbreak. This study shows the possibility of an epidemic of post‐LASIK infectious keratitis. Financial Disclosure: No author has a financial or proprietary interest in any material or method mentioned.

Risk factors for insufficient fixation of microkeratome during laser in situ keratomileusis

PURPOSE To investigate the potential risk factors leading to insufficient fixation of a microkeratome during laser in situ keratomileusis (LASIK), especially in Asian eyes. METHODS We performed a retrospective analysis of 1809 eyes of 972 patients that underwent LASIK. Profiles of patients (age, sex, past medical history, width of palpebral fissure, corneal power, and postoperative clinical course) whose operations were discontinued due to insufficient fixation were compared to all LASIK patients. RESULTS Insufficient fixation was observed in 18 eyes of 16 patients. Those patients were significantly younger (26.1 +/- 5.5 yr) compared to all patients (32.3 +/- 8.6 yr). Mean keratometric power was 42.40 +/- 1.37 D in patients with insufficient fixation and 43.60 +/- 1.40 D in all patients (P < .001). Maximum width of palpebral fissure with eyes wide open was 0.96 +/- 0.20 mm in patients with insufficient fixation, and 1.10 +/- 0.19 mm in all patients (P = .0015). These patients subsequently underwent LASIK utilizing combinations of cooling, frequent corticosteroid instillation for several hours, and lateral canthotomy. CONCLUSION Narrow palpebral fissures commonly found in Asian populations might be a risk factor for insufficient fixation of a microkeratome in LASIK, especially in young patients with flat corneas.

Dry eye after LASIK enhancement by flap lifting.

PURPOSE: To determine whether dry eye after LASIK recurs after LASIK enhancement. METHODS: A total of 63 eyes of 42 patients who underwent LASIK enhancement were included in this study. Subjective dry eye symptoms, tear break-up time (BUT), Schirmer test with anesthesia, fluorescein staining of the cornea, and corneal sensitivity were evaluated before and at 1, 3, and 6 months after enhancement. RESULTS: The subjective dry eye symptoms remained unchanged before and after LASIK enhancement. Similarly, Schirmer values and tear BUT did not exhibit statistically significant differences between the pre- and post-enhancement values. Compared with the pre-enhancement values, the fluorescein score was higher at 1 month after surgery and further improved at 3 months. In comparison with the pre-enhancement values, the corneal sensitivity was decreased at 1, 3, and 6 months after surgery. CONCLUSIONS: Patients did not complain of dry eye symptoms and tear functions were not compromised after LASIK enhancement. These results suggest that factors other than the neurotrophic effect may contribute to dry eye after LASIK.

Topography-guided Ablation for Treatment of Patients With Irregular Astigmatism

PURPOSE To evaluate the customized aspheric treatment zone (CATz) topography-guided ablation for the correction of irregular astigmatism induced by initial corneal refractive surgery or corneal injury. METHODS CATz ablation was performed on 32 eyes of 28 patients. Each procedure was performed by photorefractive keratectomy (PRK) or LASIK using a NIDEK EC-5000 excimer laser. The eyes had decentered ablations, small optical zones, decreased best spectacle-corrected visual acuity (BSCVA), and asymmetrical astigmatism. Subjective symptoms, uncorrected visual acuity (UCVA), BSCVA, refraction, corneal topography, and higher order aberrations were measured. Mean follow-up was 161.9 +/- 129.9 days (range: 90 to 492 days). RESULTS Data obtained at final postoperative follow-up show that UCVA and BSCVA increased by > or = 2 lines after CATz ablation in 17 and 11 eyes and decreased in 4 and 2 eyes, respectively. Higher order aberrations were decreased in 16 eyes and increased in 1 eye. Topographical maps were improved with decreased surface regularity index (20 eyes) and surface asymmetry index (22 eyes). Seven eyes required further enhancement for residual refractive errors. Thirteen patients (15 eyes) claimed they were satisfied with the outcome, 6 patients (7 eyes) stated that the outcome was lower than expected, and 4 patients (4 eyes) stated they were dissatisfied. CONCLUSIONS CATz topographic ablation effectively improves the quality of vision and symptoms in the majority of patients with irregular corneal astigmatism from previous excimer laser refractive surgery. However, residual or induced refractive errors may need to be corrected with a second operation after CATz.