This retrospective-prospective study aims to identify the diagnostic parameters most predictive of BSCVA in patients with OSD. Clinical, structural, and biochemical data will be collected from standard-of-care examinations and patient-reported outcome questionnaires. The goal is to determine the most informative biomarkers for visual prognosis, streamline diagnostic workflows, and support individualized management of OSD.
The study is based on the hypothesis that specific diagnostic parameters, reflecting corneal structure, ocular surface (including corneal nerve) integrity, inflammatory activity and patients' reported outcomes (questionnaires), can reliably predict BSCVA in patients with OSD. Identifying these predictors will enable evidence-based selection of diagnostic tests, streamline clinical workflows, and improve patient care efficiency. This is a monocentric, national, retrospective-prospective, observational cohort study. The design includes two complementary phases: * Retrospective cohort (n = 1,500): existing clinical records will be reviewed to extract standardized diagnostic and visual acuity data. * Prospective cohort (n = 1,000): newly enrolled patients will undergo a standardized diagnostic protocol and follow-up vists at defined time points. No experimental interventions or off-label diagnostic procedures are included; all assessments correspond to standard-of-care examinations. Overall study duration: Approximately 60 months. Retrospective phase: a cohort of 1,500 patients will be selected among those patients who have been visited at the Cornea Clinic of the OSR in the last 20 years (starting from 01 Jan 2005 to 31 dec 2025) and who have a follow up of at least 12 months. Prospective phase: the investigators will enroll a cohort of 1,000 patients who will be rectruited among those visited at the Cornea Clinic of the OSR and who will be followed up for minimum 12 months. Recruitment will be ongoing for 48 months and the last patient will exit the study by month 60. Individual patient duration: up to 12 months (baseline, 6-, and 12- month visits). Interim analyses are planned at multiple time points throughout the study, contingent on data availability and sample size progression. The precise timing of these analyses will be determined based on the pace of data collection and event occurrence, rather than fixed calendar dates. All data will be collected using standardized, validated diagnostic methods: * Corneal topography (maximum keratometry, Kmax) and pachymetry * In vivo confocal microscopy (corneal nerve density and cellular morphology) * Slit-lamp photography (conjunctival hyperemia and corneal opacity grading) * Cochet-Bonnet esthesiometer (corneal sensitivity) * Goldmann applanation tonometry (intraocular pressure) * Tear cytokine quantification (including IL-1β, IL-6, TNF-α, MMP-9, multiplex immunoassay) * Impression cytology (inflammatory cell counts) * Ocular pain/quality of life questionnaire scores (OSDI, OPAS, VAS, VFQ25, SPEED) Retrospective data will be extracted from electronic medical records, while prospective data will be entered into a dedicated electronic case report form (eCRF) using harmonized acquisition protocols.
Study Type
OBSERVATIONAL
Enrollment
1,000
IRCCS San Raffaele Scientific Institute
Milan, Italy
Best spectacle-corrected visual acuity (BSCVA) measured in logMAR
Best spectacle-corrected visual acuity will be measured using a standardized Early Treatment Diabetic Retinopathy Study chart at 4 meters after manifest refraction and best spectacle correction. Visual acuity will be reported as logarithm of the minimum angle of resolution. Expected range: -0.3 to 2.0 logMAR. Higher logMAR values indicate worse visual acuity.
Time frame: Baseline, 6, and 12 months
Maximum keratometry (K max) measured by corneal tomography
Maximum keratometry will be measured by corneal tomography. Unit of Measure is Diopters (D). Higher values indicate greater corneal steepening.
Time frame: Baseline, 6, and 12 months
Central corneal thickness (CCT) measured by corneal tomography
Central corneal thickness will be measured by corneal tomography. Unit of Measure is micrometers (µm). Lower values indicate greater corneal thinning.
Time frame: Baseline, 6, and 12 months
Corneal nerve density measured by in vivo confocal microscopy
Corneal nerve density will be measured using in vivo confocal microscopy. Unit of Measure is fibers/mm². Higher values indicate greater corneal nerve density.
Time frame: Baseline, 6, and 12 months
Corneal sensitivity measured by Cochet-Bonnet esthesiometer
Corneal sensitivity will be measured using the Cochet-Bonnet esthesiometer and reported as filament length. Unit of Measure is millimeter (mm). Higher values indicate better corneal sensitivity.
Time frame: Baseline, 6, and 12 months
Tear fluid interleukin-1 beta (IL-1β) concentration
Interleukin-1 beta concentration will be measured in tear fluid samples by tear film analysis. Unit of Measure is pg/mL. Higher values indicate greater inflammatory activity.
Time frame: Baseline, 6, and 12 months
Tear fluid interleukin-6 (IL-6) concentration
Interleukin-6 concentration will be measured in tear fluid samples by tear film analysis. Unit of Measure is pg/mL. Higher values indicate greater inflammatory activity.
Time frame: Baseline, 6, and 12 months
Tear fluid tumor necrosis factor-alpha (TNF-α) concentration
Tumor necrosis factor-alpha concentration will be measured in tear fluid samples by tear film analysis. Unit of Measure is pg/mL. Higher values indicate greater inflammatory activity.
Time frame: Baseline, 6, and 12 months
Tear fluid matrix metalloproteinase-9 (MMP-9) concentration
Matrix metalloproteinase-9 concentration will be measured in tear fluid samples by tear film analysis. Unit of Measure is ng/mL. Higher values indicate greater inflammatory activity.
Time frame: Baseline, 6, and 12 months
Inflammatory cell count measured by impression cytology
Inflammatory cell count will be measured using impression cytology of the ocular surface. Unit of Measure is cells/mm². Higher values indicate greater ocular surface inflammation.
Time frame: Baseline, 6, and 12 months
Intraocular pressure (IOP) measured by Goldmann applanation tonometry
Intraocular pressure will be measured using Goldmann applanation tonometry. Unit of Measure in mmHg. Higher values indicate higher intraocular pressure.
Time frame: Baseline, 6, and 12 months
Ocular Surface Disease Index (OSDI) score
Ocular surface symptoms and vision-related function will be assessed using the Ocular Surface Disease Index questionnaire. The total score ranges from 0 to 100, with higher scores indicating more severe ocular surface disease symptoms.
Time frame: Baseline, 6, and 12 months
Ocular Pain Assessment Survey (OPAS) quality-of-life interference score
Pain-related interference with quality of life will be assessed using the Ocular Pain Assessment Survey quality-of-life interference score. The score ranges from 0 to 10, where 0 indicates no interference with quality of life and 10 indicates maximum interference with quality of life. Higher scores indicate worse pain-related quality-of-life impairment.
Time frame: Baseline, 6, and 12 months
Visual Analog Scale (VAS) pain score
Ocular pain will be assessed using a Visual Analog Scale. The score ranges from 0 to 10, where 0 indicates no ocular pain and 10 indicates the worst imaginable ocular pain. Higher scores indicate worse ocular pain.
Time frame: Baseline, 6, and 12 months
National Eye Institute Visual Function Questionnaire-25 (VFQ-25) composite score
Vision-related quality of life will be assessed using the National Eye Institute Visual Function Questionnaire-25. The composite score ranges from 0 to 100, where 0 indicates the worst possible vision-related quality of life and 100 indicates the best possible vision-related quality of life. Higher scores indicate better vision-related quality of life.
Time frame: Baseline, 6, and 12 months
Standard Patient Evaluation of Eye Dryness (SPEED) score
Dry eye symptoms will be assessed using the Standard Patient Evaluation of Eye Dryness questionnaire. The total score ranges from 0 to 28, where 0 indicates no dry eye symptoms and 28 indicates the most severe dry eye symptoms. Higher scores indicate worse dry eye symptoms.
Time frame: Baseline, 6, and 12 months
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