www.ophthalclass.blogspot.com has the complete class and MCQs on lids and adnexa for undergraduate medical students. Part A of the second class on lids deals with the palpebral fissure, eyelid retractors (levator aponeurosis and Muller’s muscle) and protractors (orbicularis oculi). It discusses the lid to globe apposition, factors responsible for vertical and horizontal tautness of the lids, including the canthal ligaments and tarsus. Horizontal lid laxity leading to entropion and ectropion is explained. A brief outline of management of involutional ectropion and entropion is given.

1. THE EYELID MUSCLES How the lids are kept in place Dr. Anupama Karanth www.ophthalclass.blogspot.com

2. The palpebral fissure

3. What maintains the palpebral fissure? The eyelid retractors The eyelid protractors

4. Eyelid protractors

5. Eyelid rectractors

6. Upper eyelid retractors

7. Levatoraponeurosis Wide insertion into various layers of the lid Medial horn – posterior lacrimal crest Lateral horn – lateral orbital tubercle Anterior portion – skin Posterior portion – anterior tarsus Superior tarsal muscle – conjunctiva and tarsus

8. Muller’s muscle (superior tarsal muscle) Posterior part of levator 2 mm lift to the upper lid Insertion to tarsus and conjunctiva Sympathetic supply Horner’s syndrome – mild ptosis

9. Loss of retractor function Blepharoptosis – drooping of upper eyelid

10. Lower eyelid retractors

11. Lower eyelid retractors Capsulopalpebral fascia analogous to levatoraponeurosis From inferior rectus terminal fibres Encircles inferior oblique Inserts to inferior conjunctival fornix and inferior tarsal border Inferior tarsal muscle Poorly developed Posterior to capsulopalpebralfascia

12. The lid globe apposition

13. The lid and the globe Why do the eyelids not fall outwards? Why do the eyelids not turn inwards?

15. The lid globe apposition-vertical ORBITAL SEPTUM - RETRACTORS - TARSUS Orbital septum Levatoraponeurosis Muller’s muscle Tarsus

16. Loss of lid-globe apposition

17. Abnormal lid-globe relations Ectropion Eversion of eyelid margin Entropion Rolling inwards of eyelid margin

18. Ectropion - Entropion

19. Horizontal lid laxity Ectropion Entropion

20. Age related lid laxity

21. Involutionalentropion

22. Managing laxity