Faculty Bibliography

PURPOSE/OBJECTIVE:To describe severe acute corneal hydrops in a patient with previously undiagnosed keratoconus, in which anterior segment optical coherence tomography (AS-OCT) revealed a protruding ridge of tissue on either side of Descemet membrane (DM) break, treated successfully with ultrathin Descemet-stripping automated endothelial keratoplasty (UT-DSAEK). METHODS:A case report. RESULTS:A 32-year-old man presented with severe corneal hydrops in OS. He was treated conservatively with hypertonic saline. Serial AS-OCT revealed persistent edema and haze overlying a break in DM, with a ridge of protruding tissue on either side. Based on these findings, UT-DSAEK was performed. Intraoperatively, the ridge of tissue remained firmly adhered after DM removal and was felt to possibly represent posterior stroma. The patient's uncorrected visual acuity improved to 20/80. Literature review revealed 1 case with similar AS-OCT findings who underwent penetrating keratoplasty; histopathology was reported to show Descemet scrolls on either side of the break, but our analysis of this and other reports suggest that an additional layer of tissue is contained within the scroll along with DM. CONCLUSIONS:This case demonstrates severe corneal hydrops in the setting of keratoconus, in which AS-OCT revealed a ridge of protruding tissue on either side of a break in DM. UT-DSAEK led to resolution of corneal edema and improvement in stromal haze and visual acuity. Further research is required to determine the precise role of endothelial keratoplasty and potential role of posterior stromal rupture in some cases of acute corneal hydrops.

Importance/UNASSIGNED:Age-related macular degeneration (AMD), the leading cause of irreversible blindness in older adults, appears to have no effective preventive measures. The common antidiabetic drug metformin has been shown to have protective outcomes in multiple age-associated diseases and may have the potential to protect against the development of AMD. Objective/UNASSIGNED:To determine whether metformin use is associated with reduced odds of developing AMD. Design, Setting, and Participants/UNASSIGNED:This case-control study of patients from a nationwide health insurance claims database included a population-based sample of patients. Those aged 55 years and older with newly diagnosed AMD from January 2008 to December 2017 were defined as cases and matched with control participants. Data analyses were completed from June 2019 to February 2020. Exposures/UNASSIGNED:Dosage of metformin and exposure to other prescribed medications, as identified from outpatient drug claims. Main Outcomes and Measures/UNASSIGNED:Risk of developing AMD. Results/UNASSIGNED:A total of 312 404 affected individuals were included (181 817 women [58.2%]). After matching, 312 376 control participants were included (172 459 women [55.2%]; age range, 55 to 107 years). The case group had a slightly higher percentage of participants with diabetes (81 262 participants [26.0%]) compared with the control group (79 497 participants [25.5%]). Metformin use was associated with reduced odds of developing AMD (odds ratio [OR], 0.94 [95% CI, 0.92-0.96]). This association was dose dependent, with low to moderate doses of metformin showing the greatest potential benefit (dosages over 2 years: 1-270 g, OR, 0.91 [95% CI, 0.88-0.94]; 271-600 g, OR, 0.90 [95% CI, 0.87-0.93]; 601-1080 g, OR, 0.95 [95% CI, 0.92-0.98]). Doses of more than 1080 g of metformin over 2 years did not have reduced odds of developing AMD. Both the reduction in odds ratio and the dose-dependent response were preserved in a cohort consisting only of patients with diabetes. Metformin use was associated with a decreased OR of AMD in patients with diabetes without coexisting diabetic retinopathy (OR, 0.93 [95% CI, 0.91-0.95]) but was a risk factor in patients with diabetic retinopathy (OR, 1.07 [95% CI, 1.01-1.15]). Conclusion and Relevance/UNASSIGNED:In this study, metformin use was associated with reduced odds of developing AMD. This association was dose dependent, with the greatest benefit at low to moderate doses. When looking only at patients with diabetes, we saw a preservation of the dose-dependent decrease in the odds of patients developing AMD. Metformin does not appear to be protective in patients with diabetes and coexisting diabetic retinopathy. This study suggests that metformin may be useful as a preventive therapy for AMD and provides the basis for potential prospective clinical trials.

Fuchs endothelial corneal dystrophy (FECD) is the most common posterior corneal dystrophy and the leading indication for corneal transplantation in the United States. FECD is slowly progressive, and patients develop gradual corneal endothelial decompensation, eventually resulting in failure of the endothelium to maintain corneal deturgescence. Medical management consists of topical hyperosmotic agents to facilitate dehydration of the cornea, but surgical intervention is often required to regain corneal clarity. The surgical management of FECD has evolved over the past two decades as corneal transplantation techniques have allowed for more selective keratoplasty and replacement of only the diseased layers of the cornea. Prior surgical management consisted of penetrating keratoplasty (PK) that carried significant intraoperative risks associated with "open sky" as well as postoperative risks of graft rejection, wound dehiscence, postoperative astigmatism, and prolonged visual rehabilitation. In the past 15 years, endothelial keratoplasty (EK) has become the treatment of choice for endothelial disease, significantly reducing the risks associated with the surgical treatment of FECD. Here we discuss the current surgical management of FECD, including the introduction of Descemet stripping only (DSO), and highlight future investigative efforts.

BACKGROUND:Routine assessment of photophobia in the clinical setting may underestimate the presence and severity of this condition. We aimed to develop and validate a questionnaire to improve evaluation of the impact of photophobia on activities of daily living, and to determine the relationship of this questionnaire to psychophysical assessment of light sensitivity thresholds. METHODS:We developed the 17-item Utah Photophobia Symptom Impact Scale (UPSIS-17) and compared its psychometric properties to the 8-item Korean Photophobia Questionnaire (KUMC-8). Ninety five subjects with or without light sensitivity completed both questionnaires; 72 also completed laboratory-based assessment of light sensitivity thresholds. We used Rasch analysis to evaluate instrument targeting, including internal consistency and reliability. Correlation analysis was used to assess the relationship between questionnaire scores and light sensitivity thresholds. RESULTS: = 0.072). UPSIS-17 showed better instrument targeting than KUMC-8 on Rasch analysis. Person-item maps allowed for identification of questions that could be removed without affecting questionnaire validity measures. CONCLUSION:This study resulted in a shortened, 12-item questionnaire. The UPSIS-12 retained significant correlation with both the KUMC-8 and light sensitivity thresholds, yielding a simpler tool for symptom assessment, while retaining validity. This expanded tool may be useful in clinical, as well as research settings, for collection of data about disability due to photophobia.