ABSTRACT
Strip meniscometry tube (SMTube) is useful for assessing tear volume in dry eye disease. We performed an in vitro and a clinical study to examine whether the SMTube can also be used to evaluate tear quantity in lacrimal passage obstruction (LPO). In vitro experiments showed that the SMTube value and the amount of water absorption were significantly correlated (R2 = 0.816, p = 0.0008), but the measured value peaked when 4 µL was absorbed. In the clinical study, 12 eyes of 9 LPO patients and 17 eyes of 17 healthy control subjects were included. The patients' SMTube values were significantly higher than those of the control subjects (p < 0.05). The SMTube value significantly decreased after silicon tube intubation (p < 0.05). Tear meniscus height (TMH) and area (TMA), measured by anterior segment optical coherence tomography, exhibited a significant positive correlation with the SMTube value (TMH, p < 0.001, R2 = 0.396; TMA, p < 0.001, R2 = 0.366). Moreover, the SMTube value significantly correlated positively with the subjective symptom of epiphora (p = 0.012, R2 = 0.255). Thus, SMTube was useful for evaluating the tear volume and therapeutic effects in patients with LPO.
ABSTRACT
PURPOSE: This study aimed to predict the best-corrected visual acuity (BCVA) based on swept-source optical coherence tomography (SS-OCT) parameters in eyes with keratoconus. METHODS: We retrospectively reviewed 135 eyes of 135 patients with keratoconus (mean age: 31.9 ± 12.4 years). The average keratometry value and BCVA (logarithm of the minimal angle of resolution [Snellen]) were 48.68 ± 5.44 diopter and 0.20 ± 0.36 (20/25), respectively. Eleven parameters were calculated using SS-OCT. Apart from the corneal height and elevation, all the other parameters were calculated from both anterior and posterior corneal OCT data. The patients were divided into 2 groups, 1 for creating the prediction equation (prediction group, 86 eyes) and another for verifying the equation (verification group, 49 eyes). In the former, individual correlations between the BCVA and SS-OCT parameters were analyzed. A stepwise multiple regression analysis was performed with the BCVA as a dependent variable and SS-OCT parameters as independent variables. After its creation, the accuracy of the prediction equation was verified in the verification group. RESULTS: All the parameters, except for age and total corneal cylinder, showed statistically significant correlations with BCVA (P < 0.0001). Using the stepwise multiple regression analysis, we selected 2 explanatory variables: root mean square of anterior corneal elevation (standardized regression coefficient: 1.221; P < 0.0001) and total coma aberration (standardized regression coefficient: -0.575; P = 0.001; adjusted R = 0.546). The prediction was correct in 84.6% of the eyes within ±1 line of Snellen BCVA. CONCLUSIONS: Using the equation we derived from SS-OCT parameters is a promising method to predict visual function in patients with keratoconus.
