Expanding a photographic grading system for trachomatous scarring

Area of Science:

• Ophthalmology
• Public Health
• Medical Imaging

Background:

• Trachomatous scarring (TS) is a leading cause of preventable blindness.
• Accurate grading of TS severity is crucial for epidemiological studies and treatment monitoring.
• Previous photographic scales for TS severity required refinement.

Purpose of the Study:

• To assess the expansion of a four-step photographic grading scale for trachomatous scarring (TS).
• To subdivide the existing S3 grade into two distinct categories (S3A and S3B).
• To evaluate the reliability and utility of the expanded scale in detecting TS progression.

Main Methods:

• Everted eyelid images from adult women in Tanzania were analyzed for TS presence and severity.
• The S3 grade was split into S3A (one-third to <50% conjunctival scarring) and S3B (50% to <90% scarring).
• The expanded scale's reliability and ease of use were assessed, and its ability to detect progression was evaluated using prior images.

Main Results:

• Interobserver agreement for the expanded scale was high (kappa = 0.86).
• At baseline, 35.9% of S3 eyes were classified as S3A and 64.1% as S3B.
• Follow-up analysis revealed 36.6% of eyes previously not showing progression were reclassified from S3A to S3B, and S3B eyes were more likely to progress to S4.

Conclusions:

• The expanded S3A and S3B grading scale for trachomatous scarring is reliable.
• This refined scale effectively detects more instances of TS progression in photographic analysis.
• The enhanced scale will be valuable for future research on TS using photographic data.