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Biomedical subjects

Robert S Feder

Publications and source records attributed to Robert S Feder.

6 recordsLinked to original sources

Suture reaction masquerading as a conjunctival malignancy.

CASE REPORT: We report a case of conjunctival inflammation secondary to a retained suture masquerading as a neoplastic lesion. Excisional biopsy was performed in the right eye on a superior bulbar conjunctival lesion that appeared to be a conjunctival malignancy. A past history of ptosis surgery was obtained. Careful repeated examination with anesthesia, applying traction to the forniceal conjunctiva, revealed an occult polypropylene suture. Despite clinical features typical of malignancy, histologic examination revealed only chronic inflammatory cells. COMMENTS: Patients with suspicious conjunctival lesions and a history of ptosis surgery should be carefully explored for retained suture fragments. Examination with anesthesia may be needed to find an occult suture.

Biopsy↗

Pupil response to tropicamide following laser in situ keratomileusis.

PURPOSE: To investigate the effect of corneal thinning after laser in situ keratomileusis (LASIK) on the corneal penetration of topical eye medication. SETTING: Department of Ophthalmology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA. METHODS: Laser in situ keratomileusis surgery was performed in 19 eyes of 10 patients enrolled in this prospective study. Measurements were made before surgery and 3 months postoperatively. After instillation of tropicamide 1%, the change in pupil size over time was measured with a Colvard pupillometer. Central corneal thickness (CCT) was measured with ultrasonic pachymetry before and 3 months after LASIK. The corneal epithelial condition was also examined by fluorescein dye staining. RESULTS: The mean CCT decreased significantly from 564 microm +/- 33 (SD) before LASIK surgery to 514 +/- 48 microm 3 months postoperatively (P<.0001). Pupil diameter 10, 15, and 20 minutes after tropicamide 1% instillation was significantly larger 3 months after surgery than preoperatively (P=.0083, P=.0043, and P=.0144, respectively). The mean time to reach a pupil diameter of 6.0 mm decreased significantly from 14.4 +/- 4.3 minutes in preoperative eyes to 11.5 +/- 2.3 minutes in postoperative eyes (P=.0281). Mild punctate corneal epithelial staining (fewer than 5 spots) were observed in 4 eyes at the 3-month postoperative examination. CONCLUSIONS: Pupil dilation after tropicamide 1% instillation was significantly faster after LASIK surgery. Corneal thinning that resulted from LASIK enhanced corneal penetration of tropicamide 1%.

Adult↗

Baseline donor characteristics in the Cornea Donor Study.

PURPOSE: The Cornea Donor Study (CDS) is an ongoing study that is being conducted to determine whether donor age is related to long-term corneal graft survival. Characteristics of the donor population have been evaluated with respect to donor age, endothelial cell density, and death to preservation interval. METHODS: Within the context of a prospective, double-masked, controlled trial, 1101 donor corneas were assigned without regard to donor age. RESULTS: Slit-lamp characteristics of the donor corneas showed little variation with donor age, except for the presence of corneal arcus. As death to preservation time decreased, fewer epithelial abnormalities and a lower frequency of stromal edema and Descemet folds were observed. There was little change in the mean of the endothelial cell density with donor age beyond age 60, despite variation. CONCLUSION: With respect to donor age, there was little difference in either the slit-lamp characteristics or endothelial cell density of the donor corneas. Fewer epithelial abnormalities were observed with shorter death to preservation time.

Adolescent↗

Predictive formula for calculating the probability of LASIK enhancement.

PURPOSE: To develop a formula to predict a patient's need for laser in situ keratomileusis (LASIK) enhancement. SETTING: Northwestern Laser Vision Center, Department of Ophthalmology, Northwestern University, Feinberg School of Medicine, Chicago, Illinois, USA. METHODS: In this retrospective study, charts of patients who received LASIK with the Visx Star excimer laser for myopia and myopic astigmatism were reviewed. Laser in situ keratomileusis enhancement was performed in 130 of 720 eyes. Variables such as age, keratometry, spherical power, power and axis of astigmatism, and surgeon factor were compared in patients who required retreatment and those who did not. Multivariate logistic regression analysis was used to determine a formula for the probability of enhancement surgery. RESULTS: Age (P<.0001), preoperative cycloplegic sphere (P<.0001), and surgeon (P<.0001) were the statistically significant factors for predicting retreatment. The predictive formula derived from these factors had a sensitivity of 79%, a specificity of 61%, and positive and negative predictive values of 31% and 93%, respectively. CONCLUSIONS: Older age, higher preoperative cycloplegic sphere, and surgeon significantly influenced a patient's likelihood for LASIK retreatment. A formula based on these predisposing factors helps to more accurately predict the need for retreatment.

Adolescent↗