Anterior Segment Imaging in Ocular Surface Squamous Neoplasia
Table 2
Summary of advantages and disadvantages of adjunctive diagnostic modalities in OSSN.
Imaging modality
Advantages
Disadvantages
Impression cytology
(1) Inexpensive (2) Easy to perform (3) Good correlation with histopathology
(1) Assesses only superficial cells and is unable to sample deep lesions or invasive disease (2) Requires skilled professional to interpret results
Vital dye staining
(1) Inexpensive (2) Easy to use (3) High sensitivity compared to histopathology making it a good screening tool
(1) Low to moderate specificity so a large number of benign lesions would also test positive
Ultrasound biomicroscopy
(1) Good width and depth of penetration allowing the detection of invasive disease and metastasis (2) Can be used for pigmented and thick lesions
(1) Lower resolution images compared to OCT (2) Requires skilled technician or provider to perform imaging (3) Need for eyebath and reclined position (4) Limited utility in noninvasive disease
In vivo confocal microscopy (IVCM)
(1) Allows microscopic and cellular examination of lesion (2) Images are en face
(1) Requires skilled technician or provider to perform test and interpret results (2) Unable to obtain cross-sectional images and thus may miss deep disease (3) Cannot obtain comprehensive scan of entire ocular surface (4) Difficult to obtain IVCM and pathology specimens from the same site (5) Overlap in features with benign ocular surface lesions limiting its use in differentiating OSSN from benign lesions
High resolution anterior segment optical coherence tomography
(1) High resolution images (2) Easy to use, noncontact (3) High specificity and sensitivity for differentiating OSSN from pterygia (4) HR-OCT morphologic features of OSSN are well defined, allowing the differentiation of OSSN from benign and other malignant ocular lesions (5) Ability to image the same site as before and therefore can be used to monitor disease resolution after treatment
(1) Limitation in width and depth of penetration, especially in commercial models (2) Shadowing in pigmented lesions and thick lesions, therefore limiting the ability to determine the posterior limit of lesions
