敬請指教

本人才疏學淺,懇請諸位先進前輩不吝指正。歡迎光臨:空中視力保健室

2007年7月30日 星期一

Optic nerve hypoplasia

成因:

原因不明,可能與媽媽使用藥物(phenytoin, quinine, LSD, alcohol…)或DM mother, 等有關。可能是第13週出現ganglion cell degeneration有關。

表現: double ring sign (一圈yellow-white ring,外面再一圈pigment)

單側:伴 strabismus
雙側:伴 nystagmus

性別平均表現。(♀ = ♂)


相關疾病:
* de Morsier syndrome (septo-optic dysplasia)會有Optic nerve hypoplasia
* Optic nerve hypoplasia是Paradoxical pupillary phenomenon的成因之一
* fetal alcohol syndrome會有Optic nerve hypoplasia
* Optic nerve hypoplasia應安排MRI(尤其雙側更與CNS異常有關)
1. hydrocephalus
2. hydronenecephaly
3. ant. visual pathway tumor

Tearfilm

* cornea的oxygen supply來自precorneal tearfilm為主(其它少部份來自lid血管、aqueous humor)

* 淚液(tear film)中會出現的免疫球蛋白(immunoglobulin)
=> IgA, Secretory Iga(S-IgA)為主(由主淚腺及副淚腺分泌)。
=> 眼部發炎時,IgA及IgG都會提高
=> Vernal conjunctivitis時,IgE會飆高。

* Tear lysozyme可破壞bacteria cell wall, β-lysin可破壞bacteria的細胞膜,latoferrin可吸收游離鐵,抑制bacteria代謝

* Tear osmolarity在aqueous tear不足或MGD患者會升高
* tear中的potassium比serum plasma的濃度高出很多
* air-precorneal tearfilm負責最大部份的屈光度數


tear function assessment

tear breakup time
 > 10 sec 正常
 < 10 sec 異常
schirmer test
 > 10mm 正常
 < 10mm 異常
tear meniscus
 > 0.3mm 正常
 < 0.3mm 異常


* Tear break up – 跟 lipid layer相關
=> Meibomian gland dysfunction時會出現lipid tear deficiency
=> Rosacea 或 oral isobetinoin 都可能造成lipid layer異常

* Vit. A 乏是 mucin tear deficeicny 最常見的原因
=> 其它還有chemical burn, cicatricial pemphigois, Steven-Johnson syndrome, trachoma

PAX

PAX gene mutation屬於Transcription factor mutation

PAX2 mutation → optic nerve coloboma, renal hypoplasia

PAX3 mutation → Waardenburg syndrome with dystopia conthorum

PAX6 mutation → aniridia, peter anomaly , autosomal dominant keratitis, dominant foveal hypoplasia

* aniridia通常伴隨cataract and glaucoma

* 注意:幾乎所有的aniridia都由PAX mutation而來,但仍有一些partial aniridia是來自AR的Gillepre syndrome

* WAGR : Wilm's tumor, Aniridia, Genitoruinary anomaly, Mental retard (位置在11p13產生gene deletion)

Botox

Botulinum toxin type A

由 C. Botulinum取得 (肉毒桿菌素)

作用: block neuromuscular condution(bind to receptor on presynapse motor nerve terminal, and inhibit the release of acetylcholine release,是間接作用,非直接作用喔!)

* 最初用來治療blepharospasm, hemifacial spasm
* FDA在2002也aprove for cosmetic use用來除皺紋
* Acute spastic ectropion可用Botox治療


適合打botox的情形

1. post-op small residual angle strabismus有效(特別好!術後2-8週打)
2. small to moderate angle exotropia or esotropia
3. acute paralytic strabismus(如CN6 palsy)避免antagonist contracture(打在同側antagonist: MR)
=> 然而,對於單或雙側的traumatic sixth nerve palsy無效。
4. cyclic esotropia
5. 可治療active phase的thyroid ophthalmopathy
6. inflamed prephthisial eye (不適合手術者)

* 打入muscle後,2-4天後開始作用
* 眼外肌約作用5-8週(1~2個月)
=> 可能產生permanent improvement for ocular alignment
* orbicularis muscle大約作用3個月

不適合的情形(botox無效,或需要多次給予):

1. A,V pattern
2. DVD
3. oblique muscle
4. chronic paralytic strabismus (antagonist已contracture)
5. congenital nystagmus


Side effect of BOTOX injection

* Botox injection最常出現的complication: temporary ptosis (考!)

( 3週至3月,小孩25%, 大人16%,小孩比較容易)
=> 也可利用來故意造成tarsorrhaphy的效果,可治療一些corneal epithelial defect

* 第二常見: vertical strabismus 17%
* 其它少見的complication: globe rupture, retrobulbar hemorrhage …

Ectropion VS Entropion

Ectropion (外翻)

* Down syndrome會有cicatricial ectropion (考試喜歡寫entropion讓你挑錯。另外要注意Down syndrome是esotropia,不是exotropia;horizontal nystagmus,不是vertical nystagmus;是myopia而非hyperopia)
* Blepharophimosis有lateral lower eyelid ectropion secondary to ant. lamellar deficiency. (考試喜歡寫entropion讓你挑錯)

* anophthalmic ectropion–loosening lower eyelid
=> prothesis太重,太大或frequency removal所致

* ectropion可造成exposure keratitis



entropion的分類:
 congenital(horizontal laxity)
 involutional
 acute spastic cicatricial(orbicularis spasm造成)
 Cicatricial(Vertical tarsoconjunctival contracture)

* cicatricial entropion ( secondary to post. lamellar scarring)
* 結膜結痂(conjunctival scarring) → 屬cicatricial

* Involutional entropion的成因
1. Horizontal eyelid laxity
2. lid retractor鬆弛
3. 年紀造成enophthalmos

* trichiasis有inturning of lashes
* Trachoma → cicatricial entropion

* Steven-Johnson syndrome → ectropion及entropion都可能


Lid correction for entropion(重要!常考!)
=> Weis, Quickert suture, no FTSG.
常用於cicatrical entropion及厲害的involutional entropion

Repair of retractor–Weis repair
 lower eyelid retractor advancement
 lateral canthal tightening
 taping of the eyelid
 mucous membrane grafting to the posterior eyelid

Temporizing measures – 用Quickact suture(high recurrent rate)
 Horizontal eyelid tightening –lateral tarsal strip
 整層切開,再作eyelid margin rotation



治療方式比較:

* Lid correction for entropion: Weis, Quickert suture

* repair for cicatricial ectropion:skin grafting

* Repair of lower eyelid retractor can be used in entropion and ectropion.


重點整理:

Down syndrome和blepharophimosis是ECtroion!

Trachoma和Trichiasis是ENtropion

Steven-Johnson syndrome兩種都可能。

Eyelid malignancy

Basal cell carcinoma

* 是最常見的眼瞼惡性腫瘤 (佔95%)
* Slow growth,好發於下眼瞼 (上眼瞼最常見的malignancy仍然是BCC)
* 好發在六七十歲的老人(平均67歲),但有5-15%在20-40歲之間。

* Risk factors
 Smoking, excessive sun exposure
 blond hair, Celtic ancestry, blue iris (不是brown iris→AAO習題)

* S/S of eyelid BCC
Painless nodule, shiny and waxy, indurated, firm and immobile, pearly, rolled border, and with fine (small) telangiectatic vessels on the surface.(不會是clear cystic)

分類:
 Nodule type(常見)
 Morpheaform(較aggrassive)

治療:

以外科手術治療之復發率最低!故外科切除是Tx首選。
若BCC長在medial canthal region,則不能採用radiation或cryotherapy

手術:Mohs’ micrographic surgery

Mohs’ micrographic surgery
用於deep infiltrative morpheaform medial canthal tumor
可保留最多healthy tissue及確定tumor完整切除


Squamous cell carcinoma (SCC)

好犯 lower eyelid
 為BCC發生率的1/40,也是用Mohs’ micrographic surgery


Sebaceous carcinoma
 來自meibomian gland或zeiss gland (所以在upper lid比較多)
 好犯 upper eyelid,較好發於女性(女多於男),大於50歲
 然而,在upper eyelid的malignancy中,仍然以BCC最多!
 用 oil red o 及 sudan black 染細胞內的 lipid。

 細胞有 pagetoid intraepidermal involve的特性(skin spread)
 有pagetoid者要用cryotherapy,不可用radiation(無效!)
 看起來像chalazion,但loss of eyelash及meibomian surface destruction為其特徵
 常被誤認為chronic conjunctivitis ~(考!)
 預後比 BCC , SCC 還要差


malignant melanoma
 佔5% skin cancer, 但eyelid則 < 1%

分類 (前兩者皆有vertical invasive growth)
 Lentigo maligna melanoma (常見)
 Nodular melanoma (常見)
 Superficial spreading melanoma
 Acrolentignous melanoma
 Tumor厚度
 > 1.5mm會有metastasis的機會
 < 0.75mm則五年存活率98%
 若 > 4mm 則五年存活率剩50%
 Cutaneous melanoma不可使用cryotherapy(無效!) …
 雖然conjunctival melanoma使用cryothearpy有效呢!

飛車戰神–CAR and MAR

CAR : Cancer-associated retinopathy

tumor分泌recoverin蛋白質攻擊photoreceptor引起。
small-cell lung cancer引起的為最多
colon adenocarcinoma少被報告
早期眼底看起來normal
血管會比較細

CAR會侵犯視網膜的cone和rod細胞 (CAR,有C:cone,R: rod,都會)


MAR: melanoma-associated retinopathy

只攻擊rod (MAR,只有R,於是攻擊Rod)
ERG會呈現negative wave


整理:

* CAR, MAR皆屬於Type 3 hypersensitivity (口訣: 車神開Mazda 3)
* CAR會攻擊cone, rod; MAR只攻擊Rod (口訣:字母裡有什麼就攻擊什麼)


補充:

ERG會呈現negative wave者:

CSNB
X-linked Retinoschisis (XLRS)
Goldman-Farve syndrome (enhanced s-cone/blue-cone syndrome)
MAR → 表上沒有列出來