Range of refractive independence and mechanism of action of a corneal shape-changing hydrogel inlay: results and theory.

PURPOSE: To demonstrate the independence of visual performance over a range of preoperative refraction and age in presbyopes implanted with a corneal shape-changing inlay (Raindrop Near Vision Inlay). SETTING: Two multispecialty clinics, Monterrey and Tijuana, Mexico. DESIGN: Prospective case series. METHODS: The nondominant eyes of patients were implanted with the hydrogel corneal inlay beneath a femtosecond flap, centered on the pupil. Clinical outcomes included uncorrected near, intermediate, and distance visual acuity (UNVA, UIVA, and UDVA) and patient-assessed task performance in good light and dim light. Statistical analyses assessed the dependencies on preoperative age (45 to 60 years) and preoperative manifest refraction spherical equivalent (MRSE) (-0.5 to +1.5 diopters [D]). Using the inlay effect derived from wavefront measurements, an eye model was created through which letter charts were simulated. RESULTS: The study evaluated eyes of 188 patients. Postoperative UNVA, UIVA, and task performance at these distances in good light was independent of age and preoperative MRSE (P > .05). Postoperative UDVA was weakly dependent on preoperative MRSE, but distance task performance in good light was not (P > .05). In the treated eye, the mean postoperative UNVA was 20/25, UIVA was 20/25, and UDVA was 20/32. The clinical outcomes are explained by consideration of zones within the pupil generating good near, intermediate, and distance image quality. This was confirmed by visual acuity simulations. CONCLUSIONS: The continuous center-near power profile induced by the corneal shape-changing inlay provides good visual acuity and performance from distance through near over a 2.0 D range of preoperative refraction and presbyopic age. FINANCIAL DISCLOSURE: Drs. Steinert, Schwiegerling, Barragán-Garza, and Chayet are consultants to Revision Optics, Inc. Drs. Lang and Holliday and Mr. Roy are employees of Revision Optics, Inc. Drs. Steinert, Schwiegerling, Barragán-Garza, and Chayet have no financial or proprietary interest in any material or method mentioned.

Gabapentin for postoperative pain after photorefractive keratectomy: a prospective, randomized, double-blind, placebo-controlled trial.

PURPOSE: To determine whether treatment with oral gabapentin reduces postoperative pain after photorefractive keratectomy (PRK). METHODS: This prospective, randomized, double-blind, placebo-controlled study comprised 40 patients scheduled for bilateral PRK. Exclusion criteria were previous refractive surgery; diseases that could affect epithelial healing; use of antihistamines, nonsteroidal anti-inflammatory drugs, or steroids; and use of mitomycin C during PRK. Patients were divided into two groups: 20 patients received gabapentin capsules (300 mg) and 20 patients received identical placebo capsules. Visual acuity, slit-lamp examination, and a 12-question, 10-point visual numerical scale questionnaire were evaluated at each postoperative follow-up. Main outcome measures were the severity of pain at each follow-up and during the previous 24 hours. Secondary outcome measures were maximum and minimum severity of pain, healing time, uncorrected distance visual acuity, and the rating of other symptoms and potential side effects. RESULTS: The gabapentin group had less pain during the first 72 hours (P=.024 to .001). A significant difference in favor of gabapentin was found for the first 48 hours regarding minimum pain severity (P=.005 and .01 for 24 and 48 hours, respectively) and for the first 72 hours for maximum pain severity (P=.014, .007, and .001 for 24, 48, and 72 hours, respectively). No significant differences were observed for side effects, symptoms, or healing time except discomfort in favor of gabapentin during the first 24 hours (P=.043). CONCLUSIONS: Gabapentin significantly reduced postoperative pain after PRK compared to placebo, with no increase in reported side effects.

Correction of astigmatism after cataract surgery using the light adjustable lens: a 1-year follow-up pilot study.

PURPOSE: The management of preoperative and residual astigmatism is critical to obtain optimized uncorrected visual acuity. The aim of this study was to determine whether residual astigmatism could be precisely corrected postoperatively using the Light Adjustable Lens (LAL, Calhoun Vision Inc) and to determine the stability of the adjusted refraction. METHODS: Ten eyes of 10 patients with cataract and corneal astigmatism between 1.00 and 2.00 diopters (D) were included. After standard phacoemulsification and implantation of the LAL, adjustment and lock-in procedures were completed. Before adjustment and 2 weeks, 6 months, and 1 year after lock-in, a full ophthalmic examination including uncorrected distance acuity (UDVA) and corrected distance visual acuity (CDVA), autorefraction, and manifest refraction was performed. RESULTS: All surgeries, adjustments, and lock-in procedures were performed with no complications. All eyes achieved ±0.50 D of the targeted cylindrical adjustment. Mean spherical equivalent refraction was 0.03±0.84 D before adjustment and -0.06±0.25 D at final follow-up. The cylinder axis remained the same in 60% of eyes and all eyes were stable within 10° rotation at 12-month follow-up. Seven of 10 eyes achieved UDVA of 20/25 or better whereas all eyes achieved UDVA of 20/32 or better. Corrected distance visual acuity remained stable in all eyes. CONCLUSIONS: In this pilot study, the LAL proved to be an efficient, predictable, and stable method of managing astigmatism in cataract patients.

Corneal endothelial safety after ultraviolet light treatment of the light-adjustable intraocular lens.

PURPOSE: To assess the safety to the corneal endothelium of ultraviolet (UV) light treatment to a light-adjustable intraocular lens (IOL). SETTING: Codet Vision Institute, Tijuana, Mexico. DESIGN: Cohort study. METHODS: The study evaluated consecutive patients scheduled for phacoemulsification cataract surgery with implantation of a light-adjustable IOL. Endothelial cell density (ECD), variation in the size of endothelial cells, and the percentage of hexagonal cells were determined centrally with a specular microscope preoperatively, 1 week postoperatively (before UV treatment), and 6 months postoperatively. Two adjustments and 2 lock-in procedures were performed with a light-delivery system between 2 weeks and 4 weeks postoperatively. RESULTS: The study enrolled 10 patients. Specular microscopy showed a mean ECD of 2344 cells/mm(2) preoperatively. The mean overall central ECD was 2047 cells/mm(2) 1 week postoperatively and 2130 cells/mm(2) at 6 months, representing an endothelial cell loss of 12.6% and 9.1%, respectively, from preoperative values. There was no statistically significant difference in the coefficient of variation or percentage of hexagonal cells at either postoperative evaluation. CONCLUSIONS: The endothelial cell loss at 6 months correlated well with previous reports of endothelial damage after phacoemulsification with IOL implantation. The light-adjustable IOL irradiation protocol for adjustment and lock-in procedures did not seem to add to the endothelial damage caused by the cataract surgery, indicating the protocol is safe to the corneal endothelium.

Early postoperative pain following Epi-LASIK and photorefractive keratectomy: a prospective, comparative, bilateral study.

PURPOSE: To compare postoperative pain associated with epi-LASIK versus photorefractive keratectomy (PRK). METHODS: This prospective observer-masked randomized study included 40 eyes of 20 patients with myopia and astigmatism who received epi-LASIK (Moria Epi-K) in one eye and PRK in the contralateral eye. Corneal ablation was done using the NIDEK EC-5000 excimer laser. Patients were seen at days 1, 3, and 6 to rate their pain via three measuring tools: 1) a global subjective rating, 2) a 10-cm visual analog scale, and 3) an 11-point numeric scale of pain. RESULTS: On postoperative day 1, 19 of 20 patients reported pain in both eyes. Using the global subjective rating scale, patients reported more pain for those eyes treated by PRK. Although clinically relevant, this difference was not statistically significant (P = .56). Based on the 11-point numeric scale of pain and visual analog scale, mean pain scores were similar for both groups. On day 3, using the global subjective rating scale, 11 of 12 patients who had pain reported more in the epi-LASIK treated eye (P = .0005). In addition, epi-LASIK eyes demonstrated higher mean pain scores based on the other two scales (visual analog scale, P = .045 and 11-point numeric scale of pain, P = .023). Only 6 patients reported minimal pain on day 6. It was more frequently reported and slightly more marked in epi-LASIK eyes, but did not reach statistical significance. CONCLUSIONS: Epi-LASIK and PRK have similar pain on postoperative day 1, but epi-LASIK demonstrated statistically more pain than PRK on days 3 and 6.

In vivo architectural analysis of 3.2 mm clear corneal incisions for phacoemulsification using optical coherence tomography.

PURPOSE: To analyze in vivo the architecture of clear corneal incisions (CCIs) for phacoemulsification using optical coherence tomography (OCT). SETTING: Anterior Segment Department, Asociacion Para Evitar la Ceguera en Mexico, Hospital Dr Luis Sanchez Bulnes, Mexico. METHODS: A prospective masked study analyzed 20 unsutured CCIs placed superiorly and created in a uniplanar fashion with a 3.2 mm slit-angled metal keratome. All wounds were evaluated with a retinal OCT model 1, 3, and 30 days postoperatively. Intraocular pressure (IOP) and incision leakage were checked. The architecture was described according to the angle of incidence, apposition of the epithelial and endothelial margins, and wound sealing. RESULTS: No leakage was detected. The angle varied from 33 to 85 degrees; angles greater than 75 degrees were done by a surgeon in training. Wound apposition at the epithelial margin was achieved in all cases. In contrast, imperfect apposition of the endothelial margin was seen in 45% of incisions on day 1 and in 15% on day 30. Incomplete sealing of the wound was seen by OCT in 25% of cases at 24 hours and persisted in 10% of all cases at 1 month. This gaping occurred on the endothelial side and never translated to the epithelial margin. No statistical correlation was found between gaping and the angle of the incision, IOP variations, or surgeon experience. CONCLUSIONS: Although in vivo CCIs caused minor anatomic imperfections, they were clinically stable independent of incision angle, IOP variation, and surgeon experience. Incision stability may be related to careful wound construction, epithelial viability, stromal edema, and efficient endothelial pumping.

Intraoperative mitomycin and corneal endothelium after photorefractive keratectomy.

PURPOSE: To determine whether there is an increased risk to the corneal endothelium when mitomycin C (MMC) is administered after photorefractive keratectomy (PRK). DESIGN: Prospective, randomized, double-blind, placebo-controlled crossover trial. METHODS: Corneal endothelium was analyzed preoperatively and postoperatively in 18 eyes of nine patients who were administered either MMC- or balanced salt solution (BSS)-supplemented PRK at Codet Aris Vision, Tijuana, Mexico. After laser ablation, one eye was randomly assigned to intraoperative topical MMC 0.02% treatment for 30 seconds, and the fellow eye (the control eye) was treated in a standard fashion with topical BSS. Preoperative pachymetry and endothelial cell count were performed and compared with postoperative measurements after one month and three months. Main outcome measure studied was endothelial cell loss. RESULTS: There was no significant difference in the preoperative endothelial cell count between the 2 groups: MMC group 2835 +/- 395, control group 2779 +/- 492, P = .62. In the control group, at one month and three months the difference in the endothelial cell count was not statistically significant (P = .27, P = .14, respectively). However, in the MMC group the endothelial cell loss was statistically significant: at one month 14.7 +/- 5.1%, and at three months 18.2 +/- 9.0% (P = .0006, P = .002, respectively). CONCLUSIONS: The use of intraoperative topical MMC 0.02% for 30 seconds after PRK may affect the endothelial cell count.

Outcome of simultaneous phakic implantable contact lens removal with cataract extraction and pseudophakic intraocular lens implantation.

PURPOSE: To assess the outcome of simultaneous implantable contact lens (ICL) removal and cataract extraction with pseudophakic intraocular lens (IOL) implantation. SETTING: CODET Aris Vision Institute, Tijuana, Mexico. METHODS: This retrospective noncomparative interventional case series evaluated 14 eyes of 12 patients with ICL implantations who developed a cataract and simultaneously had ICL removal and cataract extraction with IOL implantation. The follow-up time was at least 6 months (range 6 to 24 months). Visual acuity (logMAR), manifest refraction, intraocular pressure, and adverse events were recorded. RESULTS: Of the 12 patients (14 eyes), 10 patients (12 eyes) had ICL surgery to correct high myopia and 2 patients (2 eyes), to correct hyperopia. The mean uncorrected visual acuity after ICL implantation (before cataract development), before cataract surgery, and after cataract surgery were 0.48 +/- 0.32, 0.83 +/- 0.34, and 0.40 +/- 0.27, respectively. The mean best corrected visual acuity (BCVA) before ICL implantation, after ICL implantation, and after cataract surgery were 0.31 +/- 0.21, 0.28 +/- 0.19, and 0.27 +/- 0.21, respectively. The mean final manifest spherical equivalent was 0.30 diopters (D) +/- 1.07 (SD) (range +2.38 to 2.0 D). Ten eyes (71.4%) were within +/-1.0 D of the calculated target. One eye had a tear in the posterior capsule with vitreous loss during cataract surgery. No other intraoperative, perioperative, or postoperative complications were observed. No loss of BCVA was recorded at the last postoperative visit. CONCLUSIONS: Lens opacities and cataract formation are a potential complication of ICL surgery. The removal of the ICL and the cataract with IOL implantation was found to be safe, with predictable refractive results.

Incidence of complications during flap creation in LASIK using the NIDEK MK-2000 microkeratome in 26,600 cases.

PURPOSE: To evaluate the incidence of intraoperative complications using the NIDEK MK-2000 microkeratome during flap creation in LASIK. METHODS: The incidence of intraoperative flap complications during LASIK using the NIDEK MK-2000 microkeratome was retrospectively studied in 26,600 procedures performed in 5 outpatient excimer laser surgery centers. RESULTS: A total of 65 (0.244%) complications were identified: 23 (0.086%) eyes had free caps, 13 (0.049%) eyes had an incomplete pass, 13 (0.049%) eyes had an epithelial defect, 11 (0.041%) eyes had buttonhole, and 5 (0.019%) eyes had irregular flap. The remaining 26,535 (99.756%) eyes had uneventful flap creation. CONCLUSIONS: Use of the NIDEK MK-2000 microkeratome resulted in a low incidence of intraoperative complications, making it a safe and reliable device for creating flaps during LASIK.

Comparison of postoperative pain in patients following photorefractive keratectomy versus advanced surface ablation.

PURPOSE: To compare postoperative pain associated with advanced surface ablation versus traditional photorefractive keratectomy (PRK). SETTING: Codet-Aris Vision Institute, Tijuana, Mexico. METHODS: This prospective double-masked randomized study included 56 eyes of 28 myopic patients who received traditional PRK in 1 eye and advanced surface ablation in the contralateral eye. For advanced surface ablation, removal of corneal epithelium was performed by incubating the cornea with 18% ethanol. Subsequently, the epithelium was removed by a surgical microsponge. For eyes treated by PRK, mechanical debridement of corneal epithelium was performed with a surgical blade. Excimer laser corneal ablation was performed using the Nidek EC-5000 excimer laser in all eyes. On postoperative days 1 and 3, patients were instructed to rate their pain via 3 pain measuring tools: (1) a global subjective rating; (2) a 100 mm visual analog scale (VAS); and (3) an 11-point numerical rating scale. RESULTS: All 28 patients completed postoperative questionnaires on day 1 and day 3. On postoperative day 1, all reported pain in both eyes. Using the global assessment rating, patients reported statistically significant more pain in eyes treated by advanced surface ablation (P = .0037; confidence interval [CI], 59%-92%). Furthermore, based on the 11-point numerical rating scale, mean pain scores were significantly higher in the advanced surface ablation treated eyes (P = .0121), while the VAS mean pain scores were marginally significantly higher (P = .0822). On postoperative day 3, 23 patients reported the presence of some pain, at least in 1 eye. Using the global assessment rating, 70% of the those who had pain reported more pain in the advanced surface ablation-treated eye (advanced surface ablation 16/23 versus PRK 7/23) (P = .0931; 95% CI, 47%-87%). In addition, on postoperative day 3, advanced surface ablation-treated eyes demonstrated slightly higher mean pain scores based on the 11-point numerical rating scale and on the VAS; however, mean differences were not statistically significant (P = .3494 and P = .3337, respectively). CONCLUSIONS: Advanced surface ablation was associated with statistically significantly more postoperative pain than PRK on postoperative day 1. A greater percentage of patients reported more pain in the advanced surface ablation-treated eyes on day 3. Refractive surgeons should consider the postoperative pain associated with advanced surface ablation when deciding on the type of epithelial debridement for their patients.

The effect of corneal flap on optical aberrations.

PURPOSE: To evaluate the changes in ocular aberrations induced by corneal flap creation. DESIGN: Prospective interventional nonrandomized clinical trial. METHODS: This study included 15 patients who were scheduled for laser in situ keratomileusis. A nasal hinge flap was created, using the Nidek MK-2000 microkeratome and then replaced without performing laser ablation. The ocular aberrations were measured before and after flap creation using the Nidek Optical Path Difference Scanning System ARK-10000. RESULTS: The root mean square wavefront errors of the higher-order optical aberrations (third-, fourth-, fifth-, and sixth-order aberrations) were not significantly altered at 1 week postsurgery compared with the preoperative values (P >.35). CONCLUSIONS: Creating a corneal flap with the Nidek MK-2000 microkeratome did not induce changes in higher-order optical aberrations as measured with the Nidek Optical Path Difference Scanning System ARK-10000 during the early postoperative period.

Lens opacities after posterior chamber phakic intraocular lens implantation.

PURPOSE: To describe a case series to determine the incidence of lens opacities after posterior chamber phakic intraocular lens (IOL) implantation (STAAR Surgical, Monrovia, CA) for very high ametropias. DESIGN: Retrospective, noncomparative, interventional case series. PARTICIPANTS: Fourteen eyes of 170 consecutive eyes with high ametropias in whom lens opacities developed after posterior chamber phakic IOL implant (PCPIOL). INTERVENTION: Posterior chamber phakic intraocular lens implant. MAIN OUTCOME MEASURES: Lens opacity appearance, localization, and clinical course. RESULTS: Fourteen eyes developed lens opacities 125 +/- 116 days after phakic IOL implant. All eyes had anterior subcapsular opacities, and two eyes also developed nuclear sclerosis. The anterior opacities did not extend posteriorly within the lens, and there were no posterior subcapsular cataracts. Seventy-one percent of opacities were first seen

Laser-assisted subepithelial keratectomy versus photorefractive keratectomy for the correction of myopia. A prospective comparative study.

PURPOSE: To compare the early postoperative visual rehabilitation after laser-assisted subepithelial keratectomy (LASEK) and photorefractive keratectomy (PRK) for the correction of myopia. SETTING: CODET Aris Vision Institute, Tijuana, Mexico. METHODS: This prospective study included 50 eyes of 25 patients with myopia who received LASEK in 1 eye and PRK in the contralateral eye. Excimer laser corneal ablation was done using the Nidek EC-5000 excimer laser. Patients were seen at 1 and 3 days, 1 week, and 1 month. Discomfort, subjective uncorrected visual acuity (UCVA), objective UCVA, best corrected visual acuity (BCVA), corneal clarity (haze), and time for corneal reepithelialization were analyzed. RESULTS: Seventy-two percent and 80% of the LASEK eyes had more discomfort at 1 day and 3 days, respectively. Eighty percent and 96% of the PRK eyes had better subjective UCVA at 1 day and 3 days, respectively. Corneas were fully reepithelialized at a mean of 3.3 days +/- 0.5 (SD) and 3.6 +/- 0.5 days in the PRK and LASEK groups, respectively. At 1 month, the UCVA was similar in both groups; no eye had lost lines of BCVA or developed haze. CONCLUSIONS: Both LASEK and PRK were effective and safe procedures in the surgical correction of myopia at the 1-month postoperative visit. Patients reported less discomfort and better visual acuity in their PRK eye during the early postoperative period. Patients should be informed that LASEK, whose acronym is similar to that of laser in situ keratomileusis, has a recovery speed that is similar to that of surface laser refractive procedures such as PRK.

Refractory intraocular pressure increase after phakic posterior chamber intraocular lens implantation.

PURPOSE: To describe a complication resulting from the implantation of a posterior chamber intraocular lens in a phakic eye. DESIGN: Interventional case report. METHODS: We examined a 37-year-old woman with severe myopia who had implantation of a phakic posterior chamber intraocular lens. RESULTS: The patient developed pigmentary glaucoma with refractory increase in intraocular pressure, despitemedical therapy and intraocular lens removal. Trabeculectomy was required to reduce the pressure. CONCLUSION: This case demonstrates that pigmentary glaucoma secondary to implantation of a phakic posterior chamber intraocular lens can lead to filtering surgery to decrease intraocular pressure.