Michael Erlanger

Characterizing the learning curve in phacoemulsification

PURPOSE: To characterize how residents learn phacoemulsification and determine which steps of the procedure are most difficult to master. SETTING: University of Colorado Hospital, Aurora, Colorado, USA. DESIGN: Comparative case series. METHODS: Cataract cases were divided into 3 levels of difficulty for comparison. Residents were given a grade for each step of the procedure by the attending surgeon. Main outcome measures were total case time and a proficiency grade. Independent variables were level of resident experience and degree of difficulty. Case times of attending cases were collected for comparison. RESULTS: Nine residents were evaluated by 4 attending surgeons while performing 324 cases of phacoemulsification. Case times of 319 attending cases were used for comparison. The easiest‐to‐learn steps (highest scores versus level of experience) included intraocular lens insertion, ophthalmic viscosurgical device removal, hydrodissection, and nucleus sculpting. Wound integrity, nucleus disassembly and removal, cortex removal, and capsulorhexis had the lowest scores versus level of experience. Resident case times decreased significantly with experience, approaching average case times for attendings. CONCLUSIONS: For this study, competency was defined as the ability of the resident to perform a case in a reasonable time without intervention or complication. Using this definition, competency was achieved when case experience exceeded 75 cataract surgeries. Financial disclosure: No author has a financial or proprietary interest in any material or method mentioned.

Ocular Biocompatibility of Nitinol Intraocular Clips

PURPOSE To evaluate the tolerance and biocompatibility of a preformed nitinol intraocular clip in an animal model after anterior segment surgery. METHODS Yucatan mini-pigs were used. A 30-gauge prototype injector was used to attach a shape memory nitinol clip to the iris of five pigs. Another five eyes received conventional polypropylene suture with a modified Seipser slip knot. The authors compared the surgical time of each technique. All eyes underwent standard full-field electroretinogram at baseline and 8 weeks after surgery. The animals were euthanized and eyes collected for histologic analysis after 70 days (10 weeks) postsurgery. The corneal thickness, corneal endothelial cell counts, specular microscopy parameters, retina cell counts, and electroretinogram parameters were compared between the groups. A two sample t-test for means and a P value of 0.05 were use for assessing statistical differences between measurements. RESULTS The injection of the nitinol clip was 15 times faster than conventional suturing. There were no statistical differences between the groups for corneal thickness, endothelial cell counts, specular microscopy parameters, retina cell counts, and electroretinogram measurements. CONCLUSIONS The nitinol clip prototype is well tolerated and showed no evidence of toxicity in the short-term. The injectable delivery system was faster and technically less challenging than conventional suture techniques.

Time and cost of teaching cataract surgery

Purpose To compare the differences in the time of completion of cataract surgery for residents and attending surgeons and to assign a dollar cost. Setting University of Colorado teaching hospital, Aurora, Colorado, USA. Design Comparative case series. Methods Cataract cases were divided into 3 levels of difficulty for comparison. Main outcome measures were total case time (incision to patch) and degree of difficulty. Results Nine residents and 6 attending surgeons participated in the study. Case times were collected for 324 resident cases and 319 attending surgeon cases. The mean attending surgeon case time was 25.75 minutes ± 12.32 (SD) and the mean resident case time, 46.35 ± 16.75 minutes. There was no significant difference in the degree of difficulty between resident cases and attending surgeon cases. Approximately 600 total cases were performed by 4 residents during 3 years of residency training. Taking into account the mean time of case completion for attending surgeons versus residents, the total difference in time if attending surgeons had performed 600 cataracts would be 12 360 minutes. Using a dollar cost of approximately

Difference in ocular surface temperature by infrared thermography in phakic and pseudophakic patients

11.24 per minute at the institution, the cost difference was calculated to be

Ocular argyrosis secondary to long-term ingestion of silver nitrate salts.

138 926.40. Conclusion There was a significant time and dollar cost incurred in teaching cataract surgery. Financial Disclosure No author has a financial or proprietary interest in any material or method mentioned.

Development of a Minimally Invasive, Injectable, Shape Memory Suture and Delivery System

Purpose To assess the change in ocular surface temperature between healthy phakic and pseudophakic patients. Methods We included patients with no history of ocular disease other than cataract. Patients were divided into three groups: clear lens, cataract, and pseudophakic. All patients had two ocular surface digital thermal scans. An average of five surface points was used as the mean ocular surface temperature. Results were analyzed with a one-way analysis of variance and a Tukey’s least significance difference test. The patients were further divided into phakic and pseudophakic groups. Correlation coefficients between several variables were done in order to assess dependencies. Results Fifty-six eyes (28 cataracts, 12 clear lenses, 16 pseudophakic) were enrolled. The mean ocular surface temperature in the cataract group was 34.14°C±1.51°C; clear lens: 34.43°C±2.27°C; and pseudophakic: 34.97°C±1.57°C. There were no statistical differences among the study groups (P=0.3). There was a nonsignificant negative correlation trend between age and surface temperature in the phakic group. The trend inverted in the pseudophakic group but without statistical significance. Conclusion Although cataract extraction and intraocular lens implantation seem to induce a mild increase in ocular surface temperature, the effect is not clear and not significant.

Management of a dislocated intraocular lens with a suction-based grasping tool

This case report describes the clinical, autofluorescence, and optical coherent tomography findings in a patient with panocular argyrosis secondary to chronic intake of diluted silver nitrate salts in his water supply. An 86-year-old Caucasian male with a distinctive gray-bluish hue of the skin presented to our clinic, having developed a slow decrease in visual acuity in both eyes and nyctalopia for the past 2 years. Based on the patient’s history of chronic intake of silver nitrate salts and a positive skin biopsy (performed by the dermatology department, data not shown), a diagnosis of panocular argyrosis was made. Fluorescein angiography showed choroidal blockage with a completely dark choroid. Fundus autofluorescence was within normal limits. Optical coherent tomography showed multiple excrescences of retinal pigment epithelium in both eyes. Although the drusen-like changes on fundus examination and retinal pigment epithelium changes may account for the diminished vision, the presence of concomitant nyctalopia suggests underlying damage of the photoreceptors.

Tarsoconjunctival pedicle flap for the management of a severe scleral melt.

Suturing in space-confined surgical settings encountered during microsurgical procedures can be technically complex and time intensive. This paper presents the development of a new injector and new shape-memory alloy clip that can replace conventional suture. Engineering and surgical assessments of the injector and clips were performed. A prototype of the delivery system was tested in simulated surgical settings and compared to conventional suturing techniques for surgical time and wound strength. In various micro-surgical scenarios, the new injectable system proved to be 5 to 20-times more efficient and to have wound strengths over three-times that of conventional suturing. Further, the wounds closed by the shape-memory alloy clips could be forced to open and then recover to a watertight state, unlike conventional sutures which break upon failure. This new injector and shape-memory alloy clips proved to be quicker, stronger, and technically easier than conventional suturing. Future work is underway to test the injectable delivery system and the shape-memory alloy clips using a real-time, in vivo porcine model.

Suction-based grasping tool for removal of regular- and irregular-shaped intraocular foreign bodies.

UNLABELLED Spontaneous late subluxation of an intraocular lens (IOL) is a rare but serious complication of cataract surgery, often associated with poor zonular support. The management of this complication with a conventional forceps is difficult because the forceps often cannot adequately grasp the optic or haptic to fixate the IOL to the sclera or iris or remove it. The new suction-based grasping tool has a suction cup at the end. The combination of a suction vector and the use of a set of specially designed suction tips allow grasping and stabilization of the subluxated IOL. The properties of the suction-based grasping tool provide better control of the subluxated IOL, simplifying the management of these challenging cases. FINANCIAL DISCLOSURE Drs. Olson and Mackenzie have a patent application pending for the disclosed device. No other author has a financial or proprietary interest in any material or method mentioned.

Intraocular lens fixation with a 30-gauge injectable shape-memory alloy clip in a porcine eye.

Purpose: To describe the use of a tarsoconjunctival pedicle flap for the repair of a large scleral melt in a patient with rheumatoid arthritis. Methods: Case report and literature review. Results: A 36-year-old woman with a history of rheumatoid arthritis presented to the Rocky Mountain Lions Eye Institute with a large scleral melt in the right eye. Ophthalmic examination revealed a visual acuity of 20/400 and a superior scleral melt measuring 15 × 30 mm. After instituting systemic immunosuppression, a tarsoconjunctival pedicle was used to provide tectonic support to the globe. At her 3-month postoperative visit, her vision improved to 20/30, and the scleral melt was completely epithelialized. Conclusions: A tarsoconjunctival pedicle flap provides an excellent alternative to help restore scleral integrity in patients with severe autoimmune necrotizing scleritis.