Biomedical subjects

Gregory J McCormick

Publications and source records attributed to Gregory J McCormick.

3 recordsLinked to original sources

PubMed2006

Keratoprosthesis: current techniques.

PURPOSE: To compare and contrast the techniques and results of keratoprosthesis (KPro) using the Cardona device (1975-1985) with those related to the use of the Dohlman-Doane type 1 device (2003-2005). METHODS: We conducted a retrospective review of 31 cases of Cardona KPro implanted between 1975 and 1981 and a review of 25 cases of Dohlman-Doane type 1 KPro implanted between 2003 and 2005. Procedures were limited to eyes with a poor prognosis for traditional penetrating keratoplasty. RESULTS: In the Cardona cases, 39% (12/31) of patients achieved a visual acuity of 20/40 or better at some point postoperatively, degrading to 16% (5/31) at the end of the observation period. Fifty percent (15/31) required subsequent surgical revision of the KPro. Sixteen percent of cases (5/31) developed endophthalmitis, and 58% (18/31) developed retroprosthetic membranes. There were 5 dislocations of the prosthesis and an additional 3 frank extrusions (26%). Of the 25 Dohlman-Doane cases, there have been no reoperations, endophthalmitis, dislocations, or extrusions to date (8/15/05). Forty-eight percent (12/25) achieved 20/200 acuity or better, and 12% (3/25) achieved 20/40 or better. Retroprosthetic membranes formed in 3 cases. CONCLUSION: Although KPro remains a technique to be used in poor prognosis keratoplasty, improvements in the design of the device and surgical technique over the past 30 years have reduced the overall morbidity and severity of complications and improved the prognosis for visual rehabilitation.

Adolescent↗

PubMed2005

Keratoprosthesis: the Dohlman-Doane device.

PURPOSE: To determine the usefulness of the Dohlman-Doane type I keratoprosthesis for visual rehabilitation in cases of poor prognosis for traditional penetrating keratoplasty. DESIGN: A retrospective, noncomparative interventional series of 25 patients who had sustained multiple graft failure or who were otherwise deemed poor candidates for conventional keratoplasty. METHODS: Candidates were evaluated for potential acuity, intraocular pressure, inflammation, the quality of the ocular surface, and overall prognosis for penetrating keratoplasty. The keratoprosthesis was assembled and mounted on an 8.5- or 9.0-mm diameter donor corneal button and sutured into an 8.0- or 8.5-mm diameter recipient bed with 12 to 16 9-0 nylon sutures. Patients were examined on the first day and subsequently in 1 week and 1 month and then at 3-month intervals. RESULTS: All devices were retained without dislocation or extrusion. There were no instances of endophthalmitis or surface infection. Fundus details were visible on the first postoperative day. Patients achieved their best acuity in an average of 2 months (range, 1 to 180 days). Improvement in acuity was observed in an average of 13 days (range, 1 to 60 days). Retroprosthetic membranes occurred in three cases, with multiple recurrences in one instance. Visual acuity ranged from no light perception to 20/25. CONCLUSION: We conclude that this prosthesis can be implanted routinely and maintained with minimal complications in poor prognosis keratoplasty, which presents the potential for visual rehabilitation.

Adult↗

PubMed2005

Higher-order aberrations in eyes with irregular corneas after laser refractive surgery.

PURPOSE: To investigate the distribution of the eye's higher-order aberrations in postoperative laser refractive surgery patients with visual complaints and highly irregular corneal shapes. DESIGN: Retrospective case-control study. PARTICIPANTS: Thirty-three symptomatic postoperative LASIK and/or photorefractive keratectomy eyes with subjective visual complaints not corrected by spectacles more than 6 months after surgery are compared with 46 normal preoperative and 46 asymptomatic successful postoperative conventional LASIK eyes. METHODS: Postoperative wave aberrations were measured for each patient using a Shack-Hartmann wavefront sensor (Zywave, Bausch & Lomb, Rochester, NY) over a 6-mm pupil. These measurements were averaged across patients with similar corneal topographic diagnoses (central islands, decentered ablations, a new group termed baby bowties, and irregularly irregular corneas). MAIN OUTCOME MEASURES: Higher-order aberrations and corneal topography. RESULTS: The average (+/-1 standard deviation) higher-order root-mean-square (rms) wavefront error values (third, fourth, and fifth orders) for the symptomatic patients was 1.31+/-0.58 microm. This was an average of 3.46 times greater than the average magnitude of normal preoperative eyes (mean rms, 0.38+/-0.14 microm), and an average of 2.3 times greater than the average magnitude of asymptomatic successful postoperative conventional LASIK eyes (mean rms, 0.58+/-0.21 microm) over a 6-mm pupil. Higher-order rms wavefront error increased with pupil size, roughly doubling for every millimeter of increasing pupil diameter. On average, eyes with central islands (n = 6) had the most vertical coma (Z3(-1); mean, -1.35+/-0.43 microm). Eyes with central islands and decentered ablations (n = 2) also had elevated amounts of spherical aberration (Z4(0); means of 0.83+/-0.11 microm and 0.69+/-0.29 microm, respectively) compared with successful postoperative LASIK eyes (mean of 0.42+/-0.20 microm). Eyes with a topographic central baby bowtie demonstrated the most secondary astigmatism (Z4(2) and Z4(-2); mean rms, 0.56+/-0.17 microm; n = 3), despite the lowest average higher-order rms (mean, 0.84+/-0.05 microm) among symptomatic topographic subgroups. Eyes with irregularly irregular corneas had a mean higher-order rms of 1.10+/-0.39 mum. CONCLUSIONS: Symptomatic postoperative laser refractive surgery patients with irregular corneas have higher-order aberrations that are 2.3 to 3.5 times greater than asymptomatic postoperative LASIK and normal preoperative eyes, respectively. The higher-order aberrations seem to correlate with corneal topography.

Adult↗