Key Structures and Abnormalities to Examine During a Slit Lamp Eye Examination
A comprehensive slit lamp examination should systematically evaluate all ocular structures from anterior to posterior, with particular attention to the cornea, anterior chamber, and eyelid margins to detect pathologies that could impact vision and ocular health. 1
External Examination
Eyelids and Lashes
- Abnormal eyelid position (ectropion, entropion)
- Incomplete eyelid closure (lagophthalmos)
- Blink response and eyelid laxity
- Loss, breakage, or misdirection of eyelashes
- Vascularization or hyperemia of eyelid margins
- Abnormal deposits/sleeves at the base of eyelashes
- Ulceration, vesicles, scaling, hyperkeratosis
- Chalazion/hordeolum
- Scarring 1
Skin
- Changes consistent with rosacea (rhinophyma, erythema, telangiectasia, papules, pustules)
- Hypertrophic sebaceous glands in malar areas 1
Tear Film
- Tear meniscus height
- Tear film break-up time and pattern
- Foamy discharge on eyelid margin
- Debris in tear film 1
Cornea
- Epithelial integrity (defects, punctate staining with fluorescein)
- Edema, infiltrates, ulcers, and scars
- Vascularization, including pannus formation
- Phlyctenules
- Stromal opacification or thinning
- Descemet's membrane folds, tears, or detachment
- Endothelial vesicles or guttae 1
Advanced Corneal Assessment
- Topography for irregular astigmatism assessment
- Pachymetry for corneal thickness measurement
- Specular microscopy for endothelial cell evaluation (density, hexagonality, uniformity)
- Confocal microscopy for in vivo microscopic imaging of corneal layers 1
Anterior Chamber
- Depth and configuration
- Cells and flare (inflammation)
- Hypopyon
- Hyphema
- Foreign bodies or residual lens material 1
Iris and Pupil
- Sphincter rupture (evidence of trauma)
- Iridocorneal adhesions
- Iris transillumination defects
- Peripheral anterior synechiae
- Posterior synechiae
- Status, shape, and position of pupil 1
Lens
- Clarity
- Position
- IOL placement (if applicable)
- IOL capture by iris 1
Posterior Segment (with appropriate lenses)
- Macular evaluation (foveal reflex, coloration, uniformity)
- Assessment for macular edema, retinal thickening
- Evaluation for hard/soft exudates, hemorrhages, microaneurysms
- Detection of retinal pigment epithelium alterations
- Identification of neovascularization 2
Special Techniques and Considerations
Illumination Methods
- Direct illumination for surface details
- Indirect illumination for deeper structures
- Sclerotic scatter for corneal opacities
- Specular reflection for endothelial examination 3
Critical Findings to Document
- Unilateral vs. bilateral abnormalities
- Diffuse vs. localized edema
- Primarily epithelial vs. stromal pathology
- Evidence of intraocular trauma (surgical or non-surgical)
- Healed or recent corneoscleral wounds 1
Common Pitfalls and Limitations
Limited Sensitivity: Wood's lamp examination (a simpler form of slit lamp) fails to detect many common eye abnormalities, including up to 44% of corneal abrasions and 50% of corneal ulcers 4
Media Opacity Challenges: Dense cataracts or corneal opacities may limit visualization of posterior structures, requiring alternative imaging techniques 2
Diagnostic Limitations: While slit lamp examination is essential, it should be complemented with specialized testing for specific conditions:
- Anterior segment OCT for high-definition cross-sectional imaging
- Confocal microscopy for detecting organisms like fungal hyphae and Acanthamoeba cysts
- Specular microscopy for endothelial cell evaluation 1
Technique Dependency: Proper patient positioning with well-supported forehead and chin is essential for thorough examination 2
Remember that while newer technologies provide valuable additional information, the slit lamp biomicroscopy remains the cornerstone of ocular examination and is compulsory when conducting a comprehensive eye evaluation 3.