Application of Second-Generation Swept-Source Anterior Segment-OCT in the Measurement of Marginal Reflex Distance-1 (MRD-1)

Blepharoptosis Associated With the Wearing of Hard Contact Lenses in Keratoconic Eyes

Keratoconus is a condition that causes progressive thinning and anterior protrusion of the cornea. Because of its irregular astigmatism, mild to moderate keratoconus is corrected with hard contact lenses (HCLs), but blepharoptosis due to the long-term wearing of HCLs is often a problem. In this study, we investigated blepharoptosis in HCL wearers with keratoconus. Thirty-seven keratoconic eyes were enrolled and divided into several groups according to their wearing history or age. Eyelid margin distance (EMD), margin light reflex distance-1 (MRD-1), and levator function (LF) were measured using a distantometer or anterior segment optical coherence tomography (AS-OCT). The EMD decreased with years of wear but showed no correlation with age; the MRD-1 decreased with years of wear and with older age; the LF showed no relationship with either years of wear or age. In the classification of ptosis, there was no severe ptosis in the present sample. The long-term wearing of HCLs is likely to cause blepharoptosis even in keratoconic eyes.

A novel method to measure margin reflex distance using the autorefractometer

PURPOSE

To determine the margin reflex distance (MRD) in healthy subjects using autorefractometer front monitor images (ARFMI) and validate the accuracy of this method by comparing it with conventional methods.

METHODS

One hundred eyes of 50 healthy subjects aged 20-59 years were included in the study. Autorefractometer front monitor images were video-recorded using a smartphone camera, and screenshots were taken to analyze the MRD. The results were compared with those from conventional methods to determine the reliability of the method. To evaluate the repeatability and reproducibility of all measurement methods, we performed two different visits by two observers.

RESULTS

The mean MRD-1 of the autorefractometer image measurement was 4.29 ± 0.90 mm, mean MRD-1 of the of the digital photography image measurement was 3.78 ± 1.03 mm, and mean MRD-1 of the manual measurement was 4.02 ± 1.09 mm. The mean difference (MD) of MRD-1 was analyzed and it was found that MD of the autorefractometer image was significantly higher than the MD of other groups (p < 0.001). The best repeatability was found in the autorefractometer image measurement [intraclass correlation coefficients (ICC): 0.960], and substantial to excellent repeatability was found in the manual (ICC: 0.903) and digital photography image measurements (ICC: 0.843). The mean inter-eye difference of MRD-1 measured by the three methods was analyzed, and there was a statistically significant difference in the autorefractometer and digital image groups (p: 0.001, p: 0.002, respectively).

CONCLUSION

Margin reflex distance measurement using ARFMI analysis is a novel, simple, accurate, reliable, and objective method. The autorefractometer device is readily available and can be found in any ophthalmic clinic. Therefore, ophthalmologists can easily measure and record MRD values and use the accurate and reliable results for follow-up and medicolegal issues.