Hani F. Sakla

Corneal sensitivity after photorefractive keratectomy and laser in situ keratomileusis for low myopia

PURPOSE To evaluate and compare the recovery of postoperative corneal sensitivity after laser in situ keratomileusis and photorefractive keratectomy for the correction of low myopia. METHODS In a prospective study, 17 consecutive eyes (17 patients) underwent laser in situ keratomileusis to correct myopia ranging from -3.25 to -6.75 diopters, and another 18 consecutive eyes (18 patients) underwent photorefractive keratectomy to correct myopia from -3.12 to -7.00 diopters. Corneal sensitivity was tested preoperatively and 1 week and 1, 3, and 6 months postoperatively using the Cochet-Bonnet esthesiometer. Corneal sensitivity was tested at the center of the cornea, and in four additional central points 2 mm from the corneal center (nasal, inferior, temporal, and superior). RESULTS Corneal sensitivity after laser in situ keratomileusis was reduced at the ablated zone during the first 3 months after surgery (Wilcoxon rank sum test, P < .05), and only after 6 months it returned to its preoperative values. However, corneal sensitivity recovered its preoperative values 1 month after photorefractive keratectomy (Wilcoxon rank sum test, P > .05), except for the central corneal point, where 3 months were required. Comparing both groups, corneal sensitivity was more depressed after laser in situ keratomileusis than after photorefractive keratectomy during the first 3 months (Mann-Whitney test, P < .05), except for the nasal central point, although no differences were found between both groups at 6 months (P > .05). CONCLUSIONS In the correction of low myopia, corneal sensitivity at the ablated zone was more depressed after laser in situ keratomileusis than after photorefractive keratectomy during the first 3 months after surgery. Only after 6 months were corneal sensitivity values similar in both groups.

Contrast sensitivity after laser in situ keratomileusis

Purpose: To evaluate the effect on contrast sensitivity function of laser in situ keratomileusis (LASIK) for the correction of myopia. Setting. Alicante Institute of Ophthalmology, University of Alicante, Spain. Methods: Fourteen eyes of 10 patients had LASIK to correct myopia ranging from 6.00 to 19.50 diopters (D). Mean preoperative myopia was 10.39 D ± 3.69 (SD). Contrast sensitivity was tested preoperatively and 1, 3, and 6 months postoperatively using the CVS‐1000E contrast sensitivity unit (VectorVision). Results: Contrast sensitivity decreased 1 month postoperatively; the decrease was significant only at the low and intermediate spatial frequencies of 3 and 6 cycles per degree (cpd) (P = .034 and .030, respectively). Starting from the first month, there was rapid recovery of contrast sensitivity and at the third month, no statistically significant decrease at all spatial frequencies. Six months after surgery, there was an increase in contrast sensitivity values at 3, 12, and 18 cpd, although the changes were not significant. Conclusion: Although LASIK decreased contrast sensitivity values at low and intermediate spatial frequencies for 1 month after surgery, these values rapidly returned to the preoperative values at 3 months. The improvement at certain frequencies at 6 months suggests that LASIK can improve the quality of vision in eyes with moderate and high myopia.

Retreatment after laser in situ keratomileusis1

Abstract Objective To evaluate the effectiveness, predictability, and safety of laser in situ keratomileusis (LASIK) retreatment for correcting residual myopia. Design Retrospective noncomparative case series. Participants and intervention Fifty-nine consecutive eyes (43 patients) underwent LASIK retreatment at 3 or 6 months after the primary LASIK procedure. Lifting the corneal flap and reablating the stromal bed with a VISX 20/20 excimer laser was the procedure used for LASIK enhancement. Main outcome measures The following parameters were studied before and after retreatment: visual acuity, refraction, videokeratography, applanation tonometry, and corneal thickness. Complications after LASIK enhancement also were evaluated. Follow-up was 12 months. Results Before retreatment, only 3.38% of eyes (2 of 59) had an uncorrected visual acuity of 0.5 (20/40) or better, and after retreatment, this percentage increased to 60% (30 of 50) at 6 months and 61.8% (34 of 55) at 12 months. After reoperation, mean best-corrected visual acuity improved by half a line over the values before retreatment. The preretreatment refraction of −2.92 ± 1.22 diopters (D) (mean ± standard deviation) decreased significantly to −0.44 ± 0.80 D at 6 months and to −0.61 ± 0.82 D at 12 months ( P P Conclusions LASIK retreatment was an effective and predictable procedure for correcting residual myopia. Epithelial ingrowth and flap melting were more frequent after than before LASIK retreatment, whereas decentration and night-vision symptoms improved.

Transient light-sensitivity syndrome after laser in situ keratomileusis with the femtosecond laser Incidence and prevention

PURPOSE: To describe the incidence of transient light‐sensitivity syndrome (TLSS) after laser in situ keratomileusis (LASIK) with the femtosecond laser and to identify preventive strategies. SETTING: Hospital NISA Virgen del Consuelo, Valencia, Spain. METHODS: The first 765 eyes operated on with the 15 KHz femtosecond laser were prospectively analyzed for subjective complaints and clinical findings compatible with TLSS. Intraoperative settings, postoperative treatment, and development of complications were analyzed. RESULTS: Overall, TLSS developed in 10 eyes (incidence 1.3%). However, the incidence decreased from 2.8% to 0.4% when aggressive topical steroids were used during the first 3 postoperative days. Postoperative interface inflammation and postoperative use of a low‐dose topical steroid regimen were associated with a higher incidence of TLSS. CONCLUSIONS: Transient light‐sensitivity syndrome is a relatively uncommon complication related to the use of the femtosecond laser. Postoperative interface inflammation may increase the probability of developing TLSS, whereas an aggressive postoperative steroid regimen seemed to provide protection against it.

Visual function after bilateral implantation of a new zonal refractive aspheric multifocal intraocular lens

PURPOSE: To evaluate visual function after bilateral implantation of a zonal refractive aspheric multifocal intraocular lens (IOL). SETTING: Private practice surgery center, Valencia, Spain. DESIGN: Cohort study. METHODS: Consecutive eyes with cataract had bilateral implantation of Lentis Mplus LS‐312 multifocal IOLs. Distance, intermediate, and near visual acuities; contrast sensitivity; defocus curves; and a quality‐of‐vision questionnaire, including presence of halos or dysphotopsia, were evaluated 6 months postoperatively. A control group of age‐matched monofocal pseudophakic patients was included to compare contrast sensitivity function. RESULTS: In the multifocal group, the mean binocular corrected distance visual acuity (logMAR) was −0.04 ± 0.07 at 6 m, 0.11 ± 0.10 at 1 m, and 0.06 ± 0.07 at 40 cm. The defocus curve showed little intermediate vision drop off. Photopic contrast sensitivity for distance was similar to the monofocal IOL contrast sensitivity function, while photopic contrast sensitivity for near and mesopic contrast sensitivity for distance with or without glare was reduced at high frequencies. The mean patient satisfaction was 8.09 ± 1.30 (scale 0 to 10); 84.4% of patients were completely independent of spectacles. Moderate halos, glare, and night‐vision problems were reported by 6.2%, 12.5%, and 15.6% of patients, respectively. CONCLUSION: The new‐generation multifocal IOL provided adequate distance, intermediate, and, to a lesser extent, near vision with high rates of spectacle freedom. Halos occurred, and other photic phenomena should be expected in a small percentage of patients. Financial Disclosure: No author has a financial or proprietary interest in any material or method mentioned.

Corneal endothelial changes after laser in situ keratomileusis

Purpose: To ascertain whether 193 nm excimer laser in situ keratomileusis (LASIK) to correct high myopia causes in vivo changes in the human corneal endothelium 3 and 6 months after surgery. Setting: Alicante Institute of Ophthalmology, University of Alicante, Spain. Methods: Preoperative and serial postoperative specular microscopy of the central corneal endothelium was done in 33 eyes of 19 patients (Group 1) with a mean age of 34.3 years ± 10.6 (SD) (range 20 to 60 years) who had LASIK to correct myopia of between 8.25 and 18.50 diopters (D) (mean 11.90 ± 2.20 D). Twelve patients (20 eyes) were contact lens wearers (Group 2), and 7 (13 eyes) had never worn contact lenses (Group 3). The central endothelium was analyzed for several parameters including cell density, coefficient of variation in cell size, and hexagonality. The data obtained before surgery were compared with those obtained after surgery in all groups. Results: There was no significant difference in age, sex, and preoperative myopia between Groups 2 and 3. In Group 1, mean cell density was significantly higher (3.5%) 6 months after surgery (P = .017) and the coefficient of variation decreased 3 and 6 months after surgery (P < .001); no significant changes were noted in the percentage of hexagonal cells. In Group 2, there was a significant increase in cell density (4.8%) 6 months after surgery (P = .010) and the coefficient of variation decreased at 3 and 6 months after surgery (P < .001); the hexagonality did not change postoperatively. In Group 3, there were no significant differences between preoperative and postoperative mean cell density, coefficient of variation, or hexagonality. Conclusion: Laser in situ keratomileusis caused no damage to the central corneal endothelium. Postoperative improvements in the endothelial cell density and the coefficient of variation in cell size values were related to the discontinuance of contact lens use after surgery.

Validity of autorefraction after cataract surgery with multifocal ReZoom intraocular lens implantation

PURPOSE: To evaluate the clinical utility of spherocylindrical automated refraction (AR) compared with subjective manifest refraction (MR) after cataract surgery with implantation of ReZoom refractive multifocal intraocular lenses (IOLs) (Advanced Medical Optics, Inc.). SETTING: Private Practice. METHODS: This prospective nonrandomized interventional study consisted of 72 patients with bilateral cataract and a potential visual acuity of at least 20/40. Patients had bilateral nonsimultaneous cataract surgery and implantation of a ReZoom IOL. Manifest refraction was performed in all patients followed by 3 consecutive measurements using the Topcon KR‐8000 autorefractor with nondilated and dilated pupils. Assessment of repeatability of multiple consecutive ARs and comparison of the AR and MR using power vector analysis were performed at the 6‐month follow‐up. The main outcome measures were the correlation between AR and MR with sphere, spherical equivalent, and astigmatism as well as the repeatability of AR before and after dilation with phenylephrine 10%. RESULTS: Repeatability analysis showed that the initial nondilated AR was not significantly different from the mean of the 3 refractions for nondilated and dilated measurements. The mean difference between the initial AR and the MR was −0.84 ± 0.62 diopters (D) for sphere (SD), −1.00 ± 0.61 D for spherical equivalent, and −0.06 ± 0.19 D and −0.01 ± 0.17 D, respectively, for J0 and J45, the 2 components of astigmatism. Linear regression of AR versus MR data showed poor correlation for sphere (R2 = 0.4852) and spherical equivalent (R2 = 0.5529), whereas the correlation for the 2 astigmatic components of vector analysis was excellent (J0, R2 = 0.8881; J45, R2 = 0.8640). Correlation was better when the MR residual refractive defect was higher. CONCLUSIONS: Although autorefraction showed excellent agreement with subjective refractive astigmatism, correlation with spherical values was poor, with a trend toward more negative values. Autorefraction after ReZoom IOL implantation can be used as a good starting point for subjective refraction of astigmatism; however, spherical values should be underestimated.

Femtosecond laser in situ keratomileusis for consecutive hyperopia after radial keratotomy

PURPOSE: To assess the use of the femtosecond laser for laser in situ keratomileusis (LASIK) in eyes with consecutive hyperopia after radial keratotomy (RK). SETTING: Private ambulatory surgical center, Valencia, Spain. METHODS: This prospective noncomparative interventional case series study included 13 eyes of 9 patients with secondary hyperopia after previous RK. The patients were operated on with the IntraLase femtosecond laser (IntraLase Corp.) and the Star S2 excimer laser (Visx, Inc.). Postoperative uncorrected visual acuity (UCVA), best spectacle‐corrected visual acuity (BSCVA), manifest refraction, flap thickness, flap diameter, and complications were evaluated at 6 months. RESULTS: The mean spherical equivalent (SE) decreased from 2.00 diopters (D) ± 0.40 (SD) to −0.41 ± 0.61 D, with 8 eyes (61.5%) within ±0.50 D of the targeted refraction. Twelve eyes (92.3%) had a UCVA of 20/40 or better, and 3 eyes (23.1%) lost 1 line of BSCVA. A mean change in SE of 0.10 D was observed at the 6‐month follow‐up. The mean flap thickness and diameter were 117 ± 14 μm and 9.18 ± 0.12 mm, respectively. Most complications were in eyes with more than 8 RK incisions than in eyes with 8 RK incisions. These complications were multiple intraoperative incision openings (100% versus 28.6%, respectively), interface inflammation (66.6% versus 0%, respectively), haze (83.3% versus 14.3%, respectively), and loss of BSCVA (50% versus 0%, respectively). CONCLUSIONS: The femtosecond laser provided large, thin corneal flaps for hyperopic LASIK. However, the procedure should be avoided in eyes with more than 8 RK incisions because of the increased risk for multiple intraoperative incision openings, interface inflammation, haze, and loss of BSCVA.

Femtosecond laser in situ keratomileusis after radial keratotomy

PURPOSE: To assess the safety, efficacy, and predictability of femtosecond laser in situ keratomileusis (LASIK) in eyes with previous radial keratotomy (RK). SETTING: Hospital Virgen del Consuelo de Valencia, Valencia, and Vissum Instituto Oftalmológico de Alicante, Alicante, Spain. METHODS: This prospective study comprised 11 eyes of 7 patients with residual low myopia after previous RK who had surgery with the IntraLase femtosecond laser (IntraLase Corp.) and the Star 2 excimer laser (Visx, Inc.). Uncorrected visual acuity (UCVA), best spectacle‐corrected visual acuity (BSCVA), defocus equivalent, refraction, flap thickness, flap diameter, and intraoperative complications were evaluated over a minimum 6‐month follow‐up. RESULTS: Although the RK incisions opened in all eyes when the flap was lifted, LASIK was successfully completed in all cases. Mean flap thickness was 119 μm ± 13 (SD). There were no cases of slipped flaps, microstriae, or epithelial ingrowth. Defocus equivalent was reduced from a mean of 2.51 ± 0.62 diopters (D) to 0.52 ± 0.28 D; 7 eyes (63.6%) were within ±0.50 D, and 11 eyes (100%) were within ±1.00 D. All eyes had 20/40 or better UCVA, although 2 eyes (18.1%) lost 1 line of BSCVA. CONCLUSIONS: The femtosecond laser was safely used to create thin LASIK flaps in eyes with previous RK. An increased postoperative inflammatory response may explain the loss of BSCVA in some cases. Efficacy and predictability of the procedure were comparable to those of LASIK after RK with mechanical microkeratomes.

Efficacy of synthetic and biological bioadhesives in scleral tunnel phacoemulsification in eyes with high myopia

Purpose: To study the efficacy of a synthetic (cyanoacrylate) and a biological (fibrinogen) bioadhesive in sealing scleral tunnel incisions in cataract surgery. Setting: Private institution with academic orientation. Methods: This controlled clinical study comprised 126 eyes with high myopia (axial length >28.0 mm) divided into three groups based on method of incision closure: 10‐0 nylon anchor suture; cyanoacrylate (Histoacryl®); fibrinogen (Tissucol®). Phacoemulsification was done through a double‐valved scleral tunnel incision with an 8.0 mm arc. In all eyes, a hyperconcave, 7.0 mm optic, posterior chamber intraocular lens was implanted. Results: Mean induced astigmatism at 12 weeks was 0.18 diopter (D) in the suture group, 0.50 D in the cyanoacrylate group, and 0.43 D in the fibrinogen group. The difference between the bioadhesive groups and the suture group was not significant. A mild inflammatory reaction occurred in the cyanoacrylate group. In the fibrogen group, 3 eyes developed postoperative hypotony requiring reclosing of the incision with sutures and 5 eyes developed intraoperative hypotony requiring suture closure. These eyes were not included in the refractive analysis. These complications led to the suspension of the fibrinogen portion of the study after uneventful use of the bioadhesive in 26 eyes. Conclusion: The results of this study indicate that bioadhesives, especially synthetic ones such as cyanoacrylate, are an effective alternative to sutures in scleral tunnel cataract surgery. Future improvements in bioadhesives could extend their application to other ocular incision types.