Measuring and Grading Deepening of Upper Eyelid Sulcus (DUES) in PGA Therapy Research
For research on DUES progression in patients receiving prostaglandin analog therapy, use serial digital facial photography evaluated by multiple masked observers comparing baseline to follow-up images at standardized intervals (2,4, and 6 months), as this represents the validated methodology used in prospective studies. 1, 2, 3
Standardized Photography Protocol
Image Acquisition
- Capture standardized digital facial photographs at baseline (before PGA initiation or at treatment switch) and at regular intervals throughout the study period 1, 2, 3
- Use consistent lighting, camera distance, and patient positioning to ensure comparability across time points 1, 2
- Photograph both eyes even if only one eye receives treatment, as this provides internal control data 3
Timing of Assessments
- Obtain photographs at 2-month intervals for the first 6 months, as this captures the typical onset period for DUES 1, 2, 3
- Extended follow-up at 12 months is valuable for assessing persistence or progression of changes 4
- The highest incidence of DUES occurs between 4-6 months of PGA therapy, making this the critical assessment window 2, 3
Objective Grading System
Observer-Masked Evaluation
- Use at least three independent, masked ophthalmologists to evaluate the photographs and reach consensus on DUES presence and severity 1, 2, 3
- Observers should compare serial photographs from the same patient side-by-side, assessing baseline versus each follow-up time point 1, 2
- Blinding observers to treatment assignment and time sequence reduces bias in progression assessment 2, 3
Grading Categories
- Binary assessment (present/absent) is the most commonly validated approach in prospective studies 1, 2, 3
- For progression studies, grade changes as: improved, unchanged, or worsened when comparing sequential time points 1, 4
- Document specific features: depth of sulcus, visibility of orbital rim, and asymmetry between eyes 1, 4
Complementary Subjective Assessment
Patient-Reported Outcomes
- Obtain patient self-reports of DUES recognition at each visit, as subjective awareness often lags behind objective findings 2, 3
- Only 8-15% of patients self-report DUES even when objectively present, making objective assessment essential 2, 3
- For recovery studies, 75% of subjectively positive patients report improvement within 2 months of switching from bimatoprost to latanoprost 1
Critical Implementation Points
Study Design Considerations
- Prospective design with standardized intervals provides the most reliable data on DUES progression 1, 2, 3
- Include baseline IOP measurements (at least 3 consecutive visits) to correlate pressure reduction with DUES development 2
- Document all demographic factors: age, sex, refractive error, visual field mean deviation, and duration of PGA use 3, 5
Drug-Specific Incidence Rates
- Bimatoprost causes DUES in 50-60% of patients within 6 months, the highest rate among PGAs 1, 5
- Latanoprost causes DUES in only 2-6% of patients at 6 months, making it useful as a comparator or switch agent 2
- Tafluprost causes DUES in 14% of patients at 6 months 3
- Travoprost data shows intermediate rates between bimatoprost and latanoprost 5
Common Pitfalls to Avoid
Methodological Errors
- Do not rely solely on patient self-reporting, as the majority of DUES cases go unrecognized by patients despite objective presence 2, 3
- Avoid single-observer assessment, as inter-observer variability is significant and consensus improves reliability 1, 2, 3
- Do not use inconsistent photography techniques, as lighting and positioning variations confound progression assessment 1, 2
Clinical Confounders
- Account for pre-existing orbital fat atrophy or aging-related changes that may mimic or mask DUES progression 1, 4
- Document concurrent medications (beta-blockers, carbonic anhydrase inhibitors) as these may influence outcomes 5
- Consider that DUES recovery is most prominent with bimatoprost-to-latanoprost switches, with 85% showing improvement at 2 months 1
Additional Outcome Measures
Associated PAP Features
- Assess other prostaglandin-associated periorbitopathy signs concurrently: lower eyelid flattening, ptosis, ciliary hypertrichosis, and periorbital hyperpigmentation 4
- DUES shows the highest recovery rate (50% at 12 months) compared to other PAP features when switching to non-PGF2α agents 4
- Ciliary hypertrichosis shows the lowest recovery rate (≤8% at 12 months), making it a less useful progression marker 4