Faculty Bibliography

PURPOSE: To evaluate the accuracy of a new method of intraocular lens (IOL) power calculation for eyes having cataract extraction after previous laser in situ keratomileusis (LASIK). SETTING: Clinical private practice and ambulatory surgical center, Astoria, New York, USA. METHODS: This retrospective study was of 12 eyes of 9 patients who presented for cataract extraction after previous LASIK. Cataract removal was performed under topical anesthesia without IOL implantation. Approximately 30 minutes later, a manifest aphakic refraction was performed. The calculation of the IOL power was obtained by using an algorithm derived from previous experience with secondary IOL implantation (Mackool algorithm). The patient then returned to the operating room for lens implantation (aphakic refraction technique). RESULTS: The refractive error 2 weeks postoperatively, defined as the difference between the intended and actual refractive outcome, ranged from 0.50 diopter (D) of unintended hyperopia to 0.75 (D) of unintended myopia. CONCLUSIONS: The aphakic refraction technique provided an extremely accurate postoperative refraction in eyes having cataract with IOL implantation surgery after previous LASIK. Although the pool sample was small (12 eyes) and the range of the aphakic refraction was limited (+8.50 to 12.375 D), the technique was found to be remarkably accurate

PURPOSE: To determine the operating temperature of ultrasonic tips used with the Alcon AdvanTec Legacy, AMO Sovereign WhiteStar, and Bausch & Lomb Millennium phacoemulsification systems. SETTING: Mackool Eye Institute, Astoria, New York, New York, USA. METHODS: Thermal imaging of ultrasonic tips (Legacy, WhiteStar, and Millennium) was performed in air and in human cadaver eyes using a duty cycle of 33% (WhiteStar) and 50% (Millennium and Legacy). In vitro temperatures were measured with the tip centered in the incision and intentionally decentered against the side of the incision. The stroke length of each instrument was also measured, and the operating frequency of the Legacy was evaluated with the addition of a tangential load. RESULTS: Open air and in vitro testing demonstrated that tip temperatures with the Legacy were consistently the lowest. Temperatures measured with the WhiteStar and Millennium systems were higher and generally similar to each other. At identical console power settings, the stroke length of the WhiteStar and Millennium tips was longer than that of the Legacy. The frequency of the Legacy handpiece did not change significantly (less than 200 Hz) under conditions of tangential tip loading. CONCLUSIONS: At identical console power settings and similar console duty cycles, the temperature elevation of ultrasonic tips was least for the Legacy and greater for the WhiteStar and Millennium under all conditions. The causes of these findings appear to be the longer stroke length of the WhiteStar and Millennium and the underestimation of the duty cycle with the WhiteStar

PURPOSE: To evaluate the safety and efficacy of the Ophtec capsular tension ring (CTR) in providing capsular support during and/or after cataract extraction in cases of a weak or partially broken ciliary zonule. DESIGN: Phase III multicenter, nonrandomized, investigational device study. PARTICIPANTS: Twelve investigators at 9 sites enrolled 224 subjects and placed 255 CTRs. METHODS: Capsular tension rings were placed in patients who were found to have a weakened or partially broken ciliary zonule comprising <34% of the circumference of the lens capsule. Two CTR models were evaluated, with noncompressed diameters of 12 mm and 13 mm. Patients were examined preoperatively, intraoperatively, and postoperatively at day 1 and months 1, 3, 6, and 12. MAIN OUTCOME MEASURES: Rate of successful stabilization of the capsular bag and intraocular lens (IOL) centration, complications, and adverse events. RESULTS: Interim results from this ongoing study indicate that immediately after surgery 98.8% of IOLs were centered and 1.2% of the IOLs implanted (3/251) were not centered. Subsequently, the prevalence of decentered IOLs was 1.7% (4/236) 3 months after surgery, 3.8% (8/211) 6 months after surgery, and 2.3% (4/172) 12 months after surgery. The primary complication was posterior capsular opacification, which is unlikely to be a complication of CTR insertion. Neodymium:yttrium-aluminum-garnet laser capsulotomies have been performed in 12.8% of eyes by 12 months (22/172). CONCLUSIONS: Ophtec CTR models 275 and 276 safely provided capsular support during and after cataract surgery in cases where the zonule was weak or partially broken

The mandibles of five patients who underwent unilateral or bilateral distraction osteogenesis were analyzed using computed tomography scans. The mandibles were reconstructed in three dimensions using General Electric computed tomography software. The total volume of each hemimandible was determined before and after distraction and compared. The mandibles were then segmented at 1-cm intervals, and the volumes of the segments were determined. The volumes of the mandibular segments before and after distraction were compared to determine the distribution of new bone through the mandible and the quantity of bone generated by distraction. The distracted hemimandibles increased in total volume by an average of 19.9% (statistically significant by the Student paired t test; P < 0.0001), whereas the nondistracted hemimandibles increased in total volume by an average of 5.2%. The segmental volumes of the distracted mandible were of similar or greater volume when compared to the preoperative mandibular segments. In addition, the distribution of regenerate bone mirrored the physiological distribution of the preoperative mandibular bone. This study indicates that distraction not only creates new bone but distributes that bone through the remodeled mandible in an anatomical pattern similar to that of the preoperative bone

PURPOSE OF REVIEW: This review describes a completely new technology for removal of the crystalline lens and compares it to currently available instruments. The AquaLase option on the Infiniti Vision System (Alcon Laboratories, Fort Worth, Texas) delivers unique advantages over conventional ultrasound phacoemulsification. RECENT FINDINGS: Incremental improvements have made ultrasonic phacoemulsification safer to the posterior capsule and less likely to create wound burn. AquaLase uses a fundamentally different technology that eliminates the risk of incision burn, is probably less likely to cause posterior capsule rupture than ultrasonic phacoemulsification needles, and is more efficient than laser-based lens removal instruments. SUMMARY: AquaLase is a new technology that offers significant advantages and is likely to find wider application as clinical experience accumulates

Mandibular distraction osteogenesis lengthens not only the affected skeleton but also the associated muscles of mastication. The purpose of this study was to determine medial pterygoid volume before and after distraction by using computed tomography. Using computed tomographic scans, the volume of the medial pterygoid muscle was determined before and after mandibular distraction in six pediatric patients. In four unilateral distraction patients (average age, 65 months), the average increase of the medial pterygoid muscle on the distracted side of the mandible was 29 percent, and on the contralateral nondistracted side, 10 percent. The average increase in medial pterygoid muscle volume in two bilateral distraction patients (each aged 8 months) was 75 percent. Results of this study demonstrate that distraction osteogenesis of the human mandible not only lengthens deficient bone, but it also increases the volume of the attached musculature

We describe a surgical technique to manage persistent corneal striae after laser in situ keratomileusis (LASIK). The sequential lift and suture technique reduces the time required for LASIK, eliminates the need to fixate the flap with forceps during suturing, and increases the accuracy of suture placement. The results in 10 eyes (9 patients) showed complete resolution of striae with improvement in subjective symptoms (glare and blurred vision) and best corrected visual acuity