Howard V. Gimbel

Early experience with the AcrySof toric IOL for the correction of astigmatism in cataract surgery

OBJECTIVE The AcrySof toric IOL (tIOL) became available in Canada in 2006, thereby giving surgeons another option in the correction of astigmatism during cataract surgery. The purpose of this paper is to report the early experience of the acrylic AcrySof tIOL. DESIGN Observational clinical study. PARTICIPANTS One hundred eleven eyes, including 41 bilateral patients. METHODS Patients were implanted with the AcrySoftIOL by 1 surgeon between April and September 2007. The eyes were followed for 6 months and pre- and postrefractive outcomes were summarized. RESULTS Preoperatively, the mean refractive cylinder was -1.25 D compared with -0.32 D postoperative. At 6 months, 95.5% of eyes remained within 10 degrees of planned axis. Two eyes of 1 patient (1.8%) required bilateral repositioning at 2 weeks postoperative for significant rotation off axis. CONCLUSIONS Based on our early postoperative experience, we have found the AcrySof tIOL to be successful in reducing moderate levels of astigmatism.

Indications, results, and complications of LASIK.

The technique of laser in situ keratomileusis (LASIK) has been used with very encouraging results in the treatment of all degrees of myopia and also shows considerable promise in the treatment of hyperopia. Compared with photorefractive keratectomy, LASIK is advantageous in causing minimal postoperative discomfort, in its rapid recovery of clear vision and stabilization of refractive change, in the infrequent occurrence of haze, and in its greater facility in correcting high degrees of myopia. However, LASIK is the more surgically demanding technique. We discuss our own experience with LASIK as well as published data from other centers. We anticipate that LASIK will continue to increase in importance in the surgical correction of refractive error.

Laser in situ keratomileusis in patients with diabetes

PURPOSE: To study the outcomes of laser in situ keratomileusis (LASIK) in patients with well‐controlled diabetes mellitus. SETTING: Gimbel Eye Centres, Calgary and Edmonton, Canada. METHODS: The charts of all patients with diabetes who had LASIK surgery at the Gimbel Eye Centres were reviewed retrospectively. Uncorrected visual acuity (UCVA), best spectacle‐corrected visual acuity (BSCVA), final refraction, and complications were assessed. RESULTS: Twenty‐four patients (16 men and 8 women) were identified. Mean patient age was 42 years (range 24 to 57 years). Seventeen patients had diabetes type II, and 7 had diabetes type I. Mean preoperative spherical equivalent (SE) was −4.88 ± 2.13 diopters (D) (range +1.625 to −9.00 D). Median follow‐up was 6 months (range 4 to 44 months). No eye lost BSCVA. Twenty‐nine eyes (63%) achieved UCVA 20/25 or better, and 31 eyes (67%) were within ±0.5 D of the intended refraction after the first LASIK surgery. Retreatment was required in 13 eyes (28.3%) because initial surgery was not adequate to correct the refractive error. At the last follow‐up visit, 40 eyes (87%) achieved UCVA of 20/25 or better and 43 eyes (93.5%) were within ±0.5 D of the intended refraction. Three eyes (6.5%) developed an epithelial defect after surgery, and secondary epithelial ingrowth developed in 2 of these eyes. No advancement of diabetic retinopathy was noticed in any eye at the end of the follow‐up period. CONCLUSIONS: Laser in situ keratomileusis surgery was safely performed in patients with well‐controlled diabetes. Enhancement may often be required for optimal correction.

The role of small-incision cataract surgery in combined cataract and glaucoma surgery.

Small-incision cataract surgery widens the scope of combined cataract and glaucoma surgery. Phacoemulsification is gaining in importance, although extracapsular extraction techniques are still commonly used. Trabeculectomy remains the standard filtration operation combined with cataract surgery. There are currently a number of areas of contention in combined trabeculectomy surgery, including-the use of shared or separate incisions, the use of antimetabolities, and the type of intraocular implant. Other adjunctive procedures such as trabeculotomy and endocyclophotocoagulation are also discussed in the context of combined surgery.

Assessment of nerve fiber layer thickness before and after laser in situ keratomileusis using scanning laser polarimetry with variable corneal compensation.

Purpose: To determine the effect of laser in situ keratomileusis (LASIK) on retinal nerve fiber layer (RNFL) thickness measurements obtained by scanning laser polarimetry with variable corneal compensation (SLP‐VCC). Setting: Gimbel Eye Centre, Calgary, Alberta. Methods: Retinal nerve fiber layer thickness measurements were performed in both eyes of 25 consecutive healthy patients the day of LASIK surgery and 1 month after by trained examiners using the GDx‐VCC nerve fiber analyzer. Thickness measurements and all other parameters provided by the software of the machine before and after LASIK were analyzed using the paired Student t test. Results: Mean age of the patients was 39 years ± 9.6 (SD) (range 24 to 57 years). The mean preoperative spherical equivalent was −4.15 ± 1.76 diopters (D) (range −1.0 to −7.50 D) and the mean postoperative spherical equivalent, 0.12 ± 0.39 D (range −0.75 to +1.00 D). Mean ablation depth was 62 ± 23 μm. No statistically significant difference was found in SLP parameters after LASIK (P<.05). No clinically significant difference in RNFL thickness measurements was noted in any eye. Conclusion: These data suggest that SLP‐VCC mean thickness measurements are not influenced by LASIK‐induced alterations in corneal architecture. Measurements obtained with SLP‐VCC before surgery may be used for future comparisons.

Suture refixation and recentration of a subluxated capsular tension ring-capsular bag-intraocular lens complex.

We describe a 3-point ab externo technique to refixate and recenter a subluxated Cionni capsular tension ring (CTR)-intraocular lens (IOL)-capsular bag complex to the sclera. A 9-0 polypropylene suture on a curved needle is looped through the eyelet of the CTR and back through a Hoffman scleral tunnel. Two other sutures passed in a similar fashion through the fibrotic continuous curvilinear capsulorhexis (CCC) edge are used to complete a tripod fixation, which centers and stabilizes the IOL. This surgical approach avoids the surgical trauma of removing and replacing a subluxated CTR-IOL-capsular bag complex, retains the optimal anatomical position, and ensures centration of the IOL.

AdvanTec Legacy System and the NeoSoniX handpiece.

AdvanTec Legacy System and the NeoSoniX handpiece (Alcon Surgical, Fort Worth, Texas) are improvements to the Legacy System that allow power modulation and customization of surgical technique in phacoemulsification surgery. AdvanTec technology allows power modulation in terms of occlusion power management, global linear flow, mode sequencing, and visco mode. The NeoSoniX handpiece combines sonic oscillations with linear ultrasound to reduce thermal energy during nucleus removal. The AdvanTec System allows lower power, less delivered energy, a lower risk of thermal burns, less chatter, and improved followability during phacoemulsification. These improvements translate into successful clinical outcomes.

Retrospective analysis of actual LASIK flap diameter compared with microkeratome ring size performed by different surgeons

Purpose: To evaluate the difference in the diameter between microkeratome ring and actual laser in situ keratomileusis (LASIK) flap size by 4 different surgeons using 3 different microkeratomes in comparison to preoperative keratometry. Setting: Gimbel Eye Centre, Calgary, Alberta, Canada. Methods: A retrospective analysis of 6667 consecutive LASIK surgeries performed at the Gimbel Eye Centre between 1998 and 2002 was conducted. The study compared the difference in the actual LASIK flap diameter and microkeratome ring size for 3 Hansatome microkeratomes indicated by serial numbers 2230, 3048, and 3084 in comparison to the preoperative keratometry. The surgeries were performed by 4 surgeons from the Centre. Results: A statistically significant correlation was found between the actual flap size and the microkeratome ring size. The deviation increased with corneal steepness (#2230: r = 0.45, P<.001; #3048: r = 0.28, P<.001; #3084: r = 0.23, P<.001). The mean difference between actual flap size and the microkeratome ring size was 0.647 mm, 0.808 mm, and 0.916 mm for Hansatome microkeratome #2230, #3048, and #3084, respectively. The actual flap was larger than the microkeratome ring size in 92.8%, 93.8%, and 97.4% of eyes, respectively. The mean difference between microkeratome ring size and measured LASIK flap size was consistently significantly different (P<.0001) per surgeon for all microkeratomes. Conclusions: Estimation of the flap size is an important issue while selecting ring size and planning the treatment zone. In this study, the actual flap size was larger than the ring size for all surgeons and all 3 Hansatome microkeratomes. Higher preoperative keratometry values achieved larger flaps than those with lower keratometry values.

In vivo two-photon imaging of retina in rabbits and rats

ABSTRACT The purpose of this study was to evaluate the retina using near‐infrared (NIR) two‐photon scanning laser ophthalmoscopy. New Zealand white rabbits, albino rats, and brown Norway rats were used in this study. An autofluorescence image of the retina, including the retinal cells and its associated vasculatures was obtained by a real‐time scan using the ophthalmoscope. Furthermore, the retinal vessels, nerve fiber layers and the non‐pigmented retina were recorded with two‐photon fluorescein angiography (FA); and the choroidal vasculatures were recorded using two‐photon indocyanine green angiography (ICGA). Two‐photon ICGA was achieved by exciting a second singlet state at ˜398 nm. Simultaneous two‐photon FA and two‐photon ICGA were performed to characterize the retinal and choroidal vessels with a single injection. The minimum laser power threshold required to elicit two‐photon fluorescence was determined. The two‐photon ophthalmoscope could serve as a promising tool to detect and monitor the disease progression in animal models. Moreover, these high‐resolution images of retinal and choroidal vessels can be acquired in a real‐time scan with a single light source, requiring no additional filters for FA or ICGA. The combination of FA and ICGA using the two‐photon ophthalmoscope will help researchers to characterize the retinal diseases in animal models, and also to classify the types (classic, occult or mixed) of choroidal neovascularization (CNV) in macular degeneration. Furthermore, the prototype can be adapted to image the retina of rodents and rabbits. HighlightsTwo‐photon excited fluorescence imaging at 780 nm allows multimodal fundus imaging with high quality and contrast.Two‐photon fundus imaging with a 30° field of view is significant.Demonstrated two‐photon fluorescein angiography (FA) and two‐photon indocyanine green angiography (ICGA).Investigated the two‐photon excitation and emission of second singlet state of indocyanine green dye.Simultaneous two‐photon FA and ICGA with a single light source were achieved requiring no additional filters.

Simplified technique for combined silicone oil removal during phacoemulsification with standard or toric intraocular lens implantation.

We describe a simple automated technique for silicone oil removal at the time of phacoemulsification combined with standard or toric intraocular lens implantation using the phacoemulsification handpiece in irrigation/aspiration mode. No additional corneal or scleral incisions are needed, and no specialized vitreoretinal instrumentation is required.