Patients at High Risk for Failure of Penetrating Keratoplasty

Purpose@#We report the clinical characteristics and the primary underlying diseases of patients at high risk for failure of penetrating keratoplasty (PKP) in Korea. @*Methods@#Patients at high risk of PKP failure among those who visited the ophthalmological clinics of tertiary care hospitals in Korea from April 2019 to April 2020 and who were indicated for PKP were retrospectively enrolled. We epidemiologically investigated 119 eyes of 104 patients via medical chart review. @*Results@#Herpes simplex virus (HSV) keratitis was the most common primary underlying disease (26.1%). The most common primary cause of poor bilateral visual acuity was Stevens-Johnson syndrome/toxic epidermal necrolysis (SJS/TEN) (41.7%) followed by chemical burns (19.4%). Of the 119 eyes, 40.3% had a history of previous PKP and 20.2% had undergone three or more PKP. The average number of prior PKPs was 1.02 ± 1.46. Corneal neovascularization and corneal opacity were reported in 82.4 and 92.4% of cases, respectively. As the severity of these conditions increased, the eye distributions became larger. Of all patients, 47.9 and 31.9%, respectively, received the highest corneal neovascularization and corneal opacity scores. @*Conclusions@#Our study of patients at high risk of PKP failure improves our understanding of the relevant clinical characteristics and primary underlying diseases. Such patients require careful observation and aggressive treatment. Possible alternatives to PKP should be considered if PKP consistently fails. This study will aid clinicians in deciding whether to proceed to surgery if a poor postoperative prognosis is predictable.

Additive Role of Optical Coherence Tomography Angiography Vessel Density Measurements in Glaucoma Diagnoses

PURPOSE: This study compared the glaucoma diagnostic abilities of optical coherence tomography (OCT) and optical coherence tomography angiography (OCTA). In addition, the possibility of enhancing diagnostic capability by combining the two modalities was investigated. METHODS: A total of 131 healthy eyes and 113 glaucomatous eyes were imaged by both OCT and OCTA. In OCT, glaucoma was defined as when the color of the superior or inferior quadrant of the peripapillary retinal nerve fiber layer thickness map was yellow (borderline, <5%) or red (outside normal limits, <1%). In OCTA, glaucoma was determined using the cut-off value of the superior or inferior peripapillary vessel density, calculated after receiver operating characteristic curve analysis. Sensitivity and specificity were determined by OCT alone, by OCTA alone, or by OCT and OCTA combined. RESULTS: The sensitivity of OCT (86.7%) was better than that of OCTA (74.3%), whereas the specificity of OCTA (87.0%) was better than that of OCT (67.9%). When these two modalities were combined, both sensitivity and specificity were enhanced (90.3% and 92.4%, respectively). Among the 131 eyes, 32 were misdiagnosed as glaucomatous by OCT but accurately diagnosed as normal by OCTA. These eyes were myopic, with a longer axial length and a thinner and temporally displaced peak of peripapillary retinal nerve fiber layer thickness, causing the false positive result in OCT. CONCLUSIONS: When OCTA was combined with OCT, the specificity of glaucoma diagnoses were enhanced. OCTA may compensate for the shortcomings of OCT in the diagnosis of glaucoma.