OPT506 - L02 - Slit Lamp Biomicroscopy 2 2024-25 Updated PDF

History & Symptoms Specialist Optometry Skills OPT506 Dr. Asma Zahidi Slit Lamp Biomicroscopy 2 Dr. Asma Zahidi One-time code: HC-YK-UK Practical session feedback 1. Remember to wipe down the slit lamp 2. Focusing – emmetrope /fully c...

History & Symptoms Specialist Optometry Skills OPT506 Dr. Asma Zahidi Slit Lamp Biomicroscopy 2 Dr. Asma Zahidi One-time code: HC-YK-UK Practical session feedback 1. Remember to wipe down the slit lamp 2. Focusing – emmetrope /fully corrected should be within ±0.50D 3. Move joystick slightly to focus on different structures 4. Keep hand on joystick to maintain image focus 5. Use both hands when using the slit lamp 6. Remember to couple the SL after decoupling 7. Leave bay tidy One-time code: HC-YK-UK One-time code: HC-YK-UK Last week 1. Direct illumination  Diffused illumination  Optic section  Paralellepiped 2. Indirect illumination techniques  Specular reflections  Sclerotic scatter  Conical beam 3. Assessing the anterior chamber angle 4. Retro Illumination https://www.menti.com/alyjaac8mjmb A Slit-Lamp Examination Flowchart White light Blue light + NaFl Lid Tears/tear film margins/eyelashes Cornea Tears/tear film Conjunctiva: Conjunctiva: ‒ Bulbar ‒ Bulbar ‒ Palpaebral (blue ‒ Palpebral and white light) Limbus Cornea Anterior chamber Iris Crystalline lens  A Slit-Lamp Examination Flowchart White light Lid margins/eye lashes Tears/tear film From the outside Conjunctiva: to the inside ‒ Bulbar ‒ Palpebral Limbus Cornea Anterior chamber Iris Crystalline lens Flow of anterior eye assessment Remember to move the illumination arm as you scan from temporal to nasal! Flow of anterior eye assessment Remember to move the illumination arm as you scan from temporal to nasal! Eye lids Scan the anterior eye along the upper lid to the inner lid angle and back along the lower lid Examine eyelid margin and eyelashes; changes and abnormalities Meibomian gland dysfunction (MGD) Visual examination of the lower lid margin for changes in the ducts of the meibomian glands Examination of the inner lid angle, the caruncles, plica semilunaris and tear punctum Redness, irritation, inclusions, changes, abnormalities, obstruction of the tear-draining pathways Eye lids Position:  Ptosis  Entropian  Ectropian Eyelashes:  Distichiasis (abnormal, additional eyelash line)  Trichiasis (lashes turning in)  Madarosis (eyelash loss) Eyelid skin:  Redness  Oedema A Slit-Lamp Examination Flowchart White light Lid margins/eyelashes Tears/tear film Conjunctiva: ‒ Bulbar ‒ Palpebral Limbus Cornea Anterior chamber Iris Crystalline lens Assessment of the tear film Non-invasive methods 1. Tear prism height 2. Non-Invasive Tear Break-Up-Time (NIBUT) 3. Lipid layer evaluation (Contact lens complication – pages 109-110) A Slit-Lamp Examination Flowchart White light Lid margins/eyelashes Tears/tear film Conjunctiva: ‒ Bulbar ‒ Palpebral Limbus Cornea Anterior chamber Iris Crystalline lens Assessing the conjunctiva White light Bulbar Lumps / bumps (pinguecula, pterygium) Hyperemia (grade & position can determine the cause) Limbus Hyperemia Limbal injection *Palpebral Upper & lower Lumps and bumps (papillae, concretions *leave upper palpebral conjunctiva after instilled NaFl A Slit-Lamp Examination Flowchart White light & Blue light Lid margins/eyelashes Tears/tear film Conjunctiva: ‒ Bulbar ‒ Palpebral Limbus Cornea Anterior chamber Iris Crystalline lens Parallelepiped vs Optic section Parallelepiped Optic section Where on the surface? How deep (which layer)?  Assessment of the Cornea Parallepiped (medium mag) Examination of the cornea and the precorneal tear film Surface texture and wettability of the cornea Detect scars, irregularities Assessment of the mobility of the tear film immediately during and after a blink, as well as the particles within the tear film Sclerotic scatter Detect scars, deposits, oedema, abnormal scattered light Optic section (medium to high magnification) Assessment on the curvature and thickness of the cornea; Determining the depth of changes and scars Specular reflection Detect changes in endothelium layer Epithelium – Microcysts and Vacuoles Microcysts Cause: Oxygen deficiency induced suppression of the metabolism Vacuoles Cause: epithelial oedema; superficial keratitis; Trauma; inherited epithelial dystrophy Microcysts (opposite refraction) Vacuoles (concurrent refraction) Stroma - Oedema Cause: fluid accumulation between the cells Findings: Subjective: streaking, foggy vision, visual fluctuations Objective: Classification using the number of striae and Descemet folds 0% corneal swelling: no striae 5% corneal swelling: single striae 7% corneal swelling: several striae 12% corneal swelling: striae and Folds 16% corneal swelling: striae, folds, microcysts and vacuoles Stroma - Oedema Striae Vertically running densifications in the stromal tissue (without ramification = delimitation to nerve fibre) Stroma - Oedema Descemet's folds Horizontal, evenly spaced, fine, whitish lines in a double contour Endothelium 25 Endothelium Polymorphism Polymegathism Altered shape of the cells – Altered form of endothelial cells, more random common in chronic hypoxia Guttata Bleps Drop-shaped protrusion of Black spots in the cell structure due to a the Descemet membrane metabolic shock and / or a into the endothelium, pH shift visible as dark spots in the cell structure Degeneration of the Descemet membrane Endothelium Bleps Gutata A Slit-Lamp Examination Flowchart White light & Blue light Lid margins/eyelashes Tears/tear film Conjunctiva: ‒ Bulbar ‒ Palpebral Limbus Cornea Anterior chamber Iris Crystalline lens Assessment of the anterior chamber VanHerick’s – Grading Grade 4 Grade 3 Grade 2 Grade 1 Grade 0 The distance The distance The distance The distance No distance between the between the between the between the between the posterior surface of posterior surface of posterior surface of posterior surface of posterior surface of the cornea and the cornea and the cornea and the cornea and the cornea and anterior surface of anterior surface of anterior surface of anterior surface of anterior surface of the iris is at least the the iris is one-half the iris is one quarter the iris is less than the iris. The angle is same width of the the width of the slit the width of the slit one quarter the considered closed, slit beam on the beam on the cornea. beam on the cornea. width of the slit and angle closure cornea. The angle is The angle is Angle closure is beam on the has occurred. considered open, considered open, possible. cornea. The angle is and angle closure is and angle closure is considered very very unlikely. unlikely. narrow, and angle closure is likely. Ratio 1:1 or more Ratio 1:0.5 -1 Ratio 1: 0.25-0.5 Ratio 1 < 0.25 closed Estimated angle: Estimated angle: Estimated angle: Estimated angle: Estimated angle: 35 – 45° 20 – 35° 20° 10° closed Let’s try some grading….. Let’s try some grading….. Let’s try some grading….. Let’s try some grading….. Let’s try some grading….. Assessing the anterior chamber Assessment of the Iris Assessment of the crystalline lens OSCE 1 – Summative DURING THE OSCE Assigned to a bay An assessor will be there to greet you Fellow student will sit as patient 1 minute reading time  Given instruction sheet with 5 techniques to do  Only do ONE eye  Assessor will let you know which eye OSCE Station 1 DURING THE OSCE 12 minutes procedure  3 basic techniques, 2 advanced techniques  Talk through each step you are doing  Show and explain the anterior eye structure that you are observing with the technique clearly and in focus  No need to record findings Questions?