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

2009年8月5日 星期三

胚胎

網膜虹睫表神經; 外肌外鞏血內皮。
水晶表角結膜淚; 其它都在神經脊。


七言絕句: 好詩!




外胚層 (Ectoderm)

表面外胚層 (Surface ectoderm)
Lens
Corneal epithelium
Cojunctiva
lacrimal glands cells


視經外胚層 (Neuroectoderm )

optic nerve
Retina (RPE and neurosensory retina)
ciliary epithelium (pigmented and nonpigmented)
Iris muscle : sphincter and dilator
Iris epithelium

神經外胚層–由後往前:
optic nerve→retina→ciliary epithelium→iris muscle+epithelium


神經脊( Neural crest)

sclera(teporal之外的大部份)
choroid
stroma of iris
corneal stroma+endothelium
trabecular meshwork
Ciliary muscle

=> cornea,iris,choroid,stroma都在neural crest!


* 中胚層 (Mesoderm)
構成:
眼外肌的muscle fiber (sheath與tendon屬於neural crest)
sclera的temporal portion (sclera的其它部份由neural crest構成)
眼部血管的endothelial lining


器官整理:
* cornea
epithelium – surface ectoderm
stroma and endothelium – neurocrest

* sclera
temporal portion–mesoderm
其它部份–neural crest

* optic nerve:neuroectoderm

* extraocular muscle
belly – mesoderm
tendon and sheath – neural crest


Uvea

* Iris
 Iris muscle (dilator/sphincter)/epithelium – neuroectoderm
 Iris stroma–neural crest

* Choroid – neural crest

* Ciliary muscle – neural crest
 Melanocyte – neural crest
 Trabecular meshwork – Neural crest

* Lens – surface ectoderm


* vitreous–mesoderm + surface ectoderm + neuroectoderm (只差沒有neural crest→因為vitreous沒有 stroma)
* Retina–neuroectoderm
* RPE–neuroectoderm


Anterior chambers 的形成是經由Neural crest cells migrate分化而來
第1波:形成corneal endothelium(1內)
第2波:形成iris, 部份papillary membrane(2彩)
第3波:形成Keratocytes(3角)

口訣: 跳土風舞:「前一二三…向內踩腳」… 1內,2彩,3角


lens embryology:

22天–optic primordium
25天–optic vesicle
27天–lens plate
29天–lens pit
33天–lens vesicle且同時optic vesicle →2 layered optic cup
40天–來至後方的cells elongated→primary lens fiber(embryonic nucleus)→7週至8個月→來至equator的epithelium分化成secondary lens fiber→fetus nucleus

suture–由於lens由外向內分泌fiber,當前後cells相會時,則形成suture,在8週時可見到前有正立Y,後有倒Y結構(前正後倒)

Tunical vasculosa lentis – 分成:
Ant. vascular capsule
 來自long ciliary a.
 形成pupillary strand
 Capsulopupillary portion
Post. vascular capsule
 來自hyaloid a.
 形成Mittendorf dot

zonular fiber在3個月大時由ciliary epithelium來
congenital aphakia – 分primary (根本沒發育)及secondary(發育後又absorb掉)


* Mesenchymal structures of the head, including the eye, are all derived from "a combination of neural crest cells and mesoderm"

* The mesoderm gives rise to all vascular endothelia, all extraocular muscles, and temporal sclera

2009年8月4日 星期二

怪怪洋名「辛左恩」–Syndrome

* Anton syndrome–雙側occipital infarction後仍聲稱可見到東西

* De Morsier syndrome (Septo-optic dysplasia)
Optic nerve hypoplasia
Midline CNS deformation
→ Absent pellucidum , corpus callosum agenesis
Pituitary dysfunction
→ Pituitary dwarfism , hypothyroidism

* Balint syndrome→會有optic ataxia(無法將眼球移到想看到的物體上),主要的lesion在post. parietal lobe

* Charks, Bonnet syndrome–hallucination和partial visual loss有關

* Crouzon syndrome:Brachycephaly (bilateral suture closure)
 有proptosis, midface hypoplasia,造成malocclusion
 有突眼 → corneal ulcer稱為parrot break,無syndactyly!

* Down syndrome:Trisomy 21

* Foster-Kennedy syndrome:由IICP造成optic atrophy,視力正常

* Pseudo-Foster-Kennedy syndrome (PFK syndrome):一眼出現atrophy,另一眼disc edema,則稱之。AAION造成之PFK syndrome,會影響視力。

* Gerstmann syndrome:看東西只看一半(hemineglect),無法分辨數字→dominant parietal lobe lesion

* Kohn-Ramono syndorme: 3q13, AD. ptosis, microcornea, strabismus, deofrmed ear, blepharophimosis, epicanthus inversus

* Klippel-Trenaunay-Weber syndrome:Sturge-Weber syndrome有trunk侵犯者稱之。
* Lowe syndrome (Oculocerebral syndrome):會有眼病變(白內障)、腎病變(血尿蛋白尿等)、腦病變(metal retard),X-link。

* Louis-Bar syndrome: Ataxia-telangiectasia (AR),在Chr. 11,與DNA repair有關,Leukemia, lymphoma機會也會上升

* Mobius syndrome
 Lesion在pons
 Aplasia of 6th nerve nucleus及雙側facial palsy,
 6th n. nucleus不僅管同側眼球abduction,同時還透過MLF管對側的adduction

* Parinaud syndrome(即Pretectal syndrome/ dorsal midbrain syndrome)
 lid retraction (Collier)
 convergence-retraction nystagmus
 saccadic paresis of upgaze (absent upgaze)

* Riley-Day syndrome又叫familial dysautonomia
=> 即先天性的自律神經失調,會有tear production減少及neurotrophic keratitis的情形;造成corneal dryness→recurrent corneal erosion→ cornea scarring

* Sturge-Weber syndrome(Cerebrofacial angiomatosis )會有POAG, seizure,Port-wine, choroidal hemangioma, cerebral calcification。

* Wallenberg syndrome:Vestibular imbalance來自stroke of lateral medulla

* Wyburn-Masson syndrome (Racemote angioma)。病理: intracranial + retinal AVM,非遺傳,好發optic disc, retina血管不會leak。

Retinoblastoma大集合

兒童最常見的眼內惡性腫瘤

發生率1/15000,
一歲前診斷多為家族性(hereditary)且雙側性case
1-3歲診斷多為單側且sporadic case,5歲以後則少見

Retinoblastoma最常見的initail sign為「白瞳」 → leukocoria
而20%有strabismus

D/D: Coats disease(最像Retinoblastoma), PHPV, ROP, Cataract, Toxocariasis, RD, VH…等等。

生長方式
endophytic growth (有vitreous seeding)
或exophytic (可能像Coats disease,有大量exdudative RD)




* 用CT可「輔助診斷」;不可做biopsy,因為tumor會seeding (重要!常考!)
* pre-treatment imaging modality: 用MRI及ultrasound of the head and neck(因為可避免CT的radiation)。




Rb gene異常,位於13q14

60%非遺傳, 40%遺傳 (重要!常考!)
65%單側, 35%雙側 (重要!常考!)




可用neuro-specific enolase, rod-outer segment photoreceptor-specific S antigen及 rhodopsia染色

tumor cell分泌 interphotoreceptor retinoid bindingprotein
細胞可見到necrosis及calcification






Retinoblastoma可見到的組織型態:

1. Fleurette:
=> 一群rod及 cone的inner segment聚集
=> 分化程度比Flexner-Wintersteiner rosette還高
口訣: Flute-inner-highly differentiated (笛子含在嘴巴裡用力吹出高音)

2. Flexner-Wintersteiner rosette:
=> 除了可見pineoblastoma外,不會在其它neuroblastic tumor見到
=> 是一種retinal differentiation的表現(最常見的一種)
=> 不是primitive ganglion cells!
口訣: Winter-Pine(冬天的松果是松鼠唯一的食物,除此之外,再沒找到其它的食物了)

3. Homer-Wright rosette:
=> 無retinal分化表現
=> 可在其它neuroblast tumor找到(medulloepithelioma)
口訣: Homer-blaster (洋基隊的炮手打出全壘打)

分化程度: Fleurette > FW rosette > HW rosette ( 口訣:FFWW )

* 但是這三種rosette跟預後無關!
=> Retioblastoma的預後與optic nerve是否有involvment有關



Retinocytoma
* 有人認為可視為retinoblastoma的良性表現(同樣的gene loci,Rb gene的問題)
* 會有Fleurette(photoreceptor之分化)

retinocytoma 與 retinoblastoma不同之處
* retinocytoma細胞質多且核分布較均
* retinocytoma可見到calcification,但通常不會有necrosis

retinoblastoma合併的secondary malignancy為osteosarcoma且和是否有做external beam radiation會增加其發生

medulloepithelioma (dikytoma)
* 通常來自cilliary body nonpigment epithelium
* tumor cell會呈現ribbon like structure
* 也可見Homerwright rosette
* malignant medulloepithelioma若lesion還在眼內通常還算benign course


親人沒有retinoblastoma,小朋友有retinoblastoma的機會: < 1%
一親人有單側retinoblastoma,小朋友有retinoblastoma的機會: 7~15%
一親人有雙側retinoblastoma,小朋友有retinoblastoma的機會: 45%


親人沒有retinoblastoma,若其孩子有Retinoblastoma,則unilateral的機會: 67%
親人沒有retinoblastoma,若其孩子有Retinoblastoma,則bilateral的機會: 33%
一親人有bilateral(或unilateral)retinoblastoma,若其孩子有Retinoblastoma,則unilateral的機會: 15%
一親人有bilateral(或unilateral)retinoblastoma,若其孩子有Retinoblastoma,則unilateral的機會: 85%

新發現的retinoblastoma之中,只有5%有family history


結論:
1. 如果父母之中都沒有retinoblastoma,則患童之中,單側的機率就是15%,雙側的機率就是85% (單側>雙側)
2. 只要父母之中有retinoblastoma,不論是單側或雙側,則患童之中,單側的機率就是15%,雙側的機率就是85% (雙側>單側)


Therapy

* Enucleation
主要用於large unilateral tumor, 約95%以上cure rate,但若cutend有tumor則預後不好

目前還是最常用的治療方法!

* R/T:reitnoblastoma對R/T很sensitive, 但若1歲以下小孩做R/T可能會誘發secondary tumor risk (osteosarcoma)

* Plaque radiotherapy:侷限 < 16mm base diameter及thickness < 8mm 可用

* Cryotherapy and laser photoablation: 3.5~4.5mm base有效

治療後可能留下type 1(calcified mass)或type 2 (translucent grayish lesion)和未治療tumor難分

最常轉移部份:orbit, CNS, cranium

單側病患有20% fellow eye也會有,自4月follow一次到3-4歲,然後6月follow一次到6歲大

2009年8月2日 星期日

Thyroid Eye Disease

名號功德不可思議!

Graves eye disease的別名(都代表同一個疾病)
1. Graves Ophthalmopathy
2. von Basedow eye disease (歐洲較常用)
3. Thyroid Ophthalmopathy
4. Thyroid Associated Ophthalmopathy (TAO)
5. Thyroid Eye Disease (TED)


主要因為有TSH-receptor stimulating immunoglobulin
佔了85% thyrotoxicosis
作用於fibroblast上
會分泌Glycosaminglycan,使tissue swelling

女性比男性多六倍 ( TED ♀ > ♂ – 7 : 1 )
Ophthalmopathy程度高低與 T3 / T4 level 無關!
Ophthalmopathy程度高低與 TSH receptor Antibody(Ig) level 有關!


TED的表現:

* 「Eyelid retraction」是 Graves disease最常見的特色 (90%) ~重要!

* 其它:
exophthalmos 60%, 眼外肌影響 40%, optic nerve dysfunction 6%

complete TED:上述所有症狀皆俱者,加上hyperthyroidism:只佔5%
Thyroid function normal者:仍可能有TED


Grave’s ophthalmopathy
最常影響的眼外肌: MR, IR
最少影響的眼外肌–lateral rectus
=> 眼外肌的enlargement呈fusiform, 而且spares the tendons(重要!)

四條直肌受TED影響的順序: IR→MR→SR→LR
口訣: I'm Super Lady (Thyroid Eye的大眼妹)



TED是成人單側或雙側之proptosis的最常見原因,也是兒童雙側proptosis的最常見原因。(兒童單側:cellulitis)



Smoking 會惡化Graves disease
抽煙量和其惡化程度呈正比


Surgical treatment of TED (依順序由先而後) 口訣:窩→肉→皮 (由深處往淺處做)
 orbital decompression (窩)
 strabismus surgery (肉)
 eyelid surgery (皮)


systemic steroids on TED

 用於有compressive optic neuropathy者
 在等待decompression surgery之前使用


TED Surgical indications (口訣:COP)

1. Corneal exposure
2. Optic neuropathy
3. Proptosis

2009年7月31日 星期五

眼表面的腺體


淚液有三種成份:LAM (lipid+Aqueous+Mucin)

Lipid(Oil): holocrine
Meibomian glands + Zeis glands



Aqueous:屬exocrine
lacrimal glands → 主淚腺
Krause,Wolfring glands → 位於eyelid上的副淚腺



Mucin:屬holocrine
Goblet cells → 位於conjunctiva及caruncle



Sweat:屬eccrine
Moll gland



整理:

Aqueous皆是exocrine
Oil及mucous皆是holocrine
Sweat屬eccrine

2009年7月27日 星期一

青光眼分類大表

依流出受阻機轉不同而作的青光眼分類(必考!)



Open-angle

一、Pretrabecular (membrane overgrowth)

 NVG, ICE,PPMD (也有機會發生在angle closure)
 Fuchs heterochromic iridocyclitis
 NV與PAS無關、也不屬於secondary angle-closure

二、 Trabecular (直接阻塞)

 Idiopathic : POAG, JOAG
 RBC: Ghost cell glaucoma
 Pigment : Pigmentary glauacoma, exfoliation syndrome
 Protein: uveitic glaucoma, lens-induced glaucoma
 Tumor: juvenile xanthogranuloma, metastasis, primary ocular tumors
 Viscoelastics: 眼內手術後,viscoat / healon沒吸乾淨
 α-chymotrypsin-induced glaucoma
 Trabeculum結構改變: steroids, trabeculitis, alkali burn, angle recession  IOFB: hemosiderosis, chalcosis

三、 Post-trabecular

 C-C fistula
 Sturge-Weber syndrome
 Mediastinal tumors , retrobulbar tumors
 Sup. vena cava syndrome
 Thyroid eye



Angle closure

一、 Anterior (Pulling)

 ICE, NVG, PPMD
 考題:NVG與pupillary block無關!而是與peripheral ant. synechiae相關
 Trauma(penetrating or non-penetrating皆可能)
Secondary angle-closure with NV : OIS, CRVO, chronic retinal detachment

二、 Posterior (Pushing)

 有pupillary block (考!)
 phacomorphic lens
 pseudophakia,
 intumescent lens
 micropherophakia
 uveitis
 ectopia lentis (如Marfan syndrome)

三、 無pupillary block

 PHPV, ROP
 Tumors: melanoma, retinoblastoma (記得要掃B-scan)
 Anterior chamber angle發育異常
 Axenfile-Rieger syndrome
 Peters anomaly



補充:

Angle Recession

cleavage between circular and the longitudinal fibers of the ciliary muscle.
Trabeculum往後轉,若範圍夠大,眼壓會升高。

2009年5月30日 星期六

分類就是學問–Collagen type

Collagen目前有19種,以下略述容易被提及的重點

Type 1 collagen
=> 屬fibril-forming, 組成多數的connective tisse
=> corneal stroma的主要成份 (佔70%的wet weight of corneal stroma)
=> scleral stroma的主要成份

Type 3 collagen
=> corneal stroma及scleral stroma也有
=> 與corneal wound healing有重要關聯

Type 4 collagen
=> 所有的basement membrane都屬之
=> 例如 : Descemet's membrane主要成份就是type 4 collagen
=> 而Bowman's layer不是BM,所以不屬之。(AAO Sec.8第一題)


依器官整理:

Cornea: Type 1,3,5,6,7,12,14
=> Descemet's membrane: type 4,8
=> corneal epithelium的anchoring fibril: type 7
=> Bowman's layer 由 type 1,5,6 collagen 組成

Sclera: Type 1,3 …

Vitreous: Type 2,5,9,11
=> type 2構成主要的fibril
=> type 9構成surface的fibril

結論: 分類就是學問,背不起分類,人生就是黑白的 …



例題1: Vitreous裡主要的collagen不包含何者 ?
a. type 1 collagen
b. type 2 collagen
c. type 5 collagen
d. type 9 collagen
答: a

例題2:下列何者以type 4 collagen為主要成份之一?
a. Vitreous
b. External limiting membrane
c. Bowmann's layer
d. Descemet membrane
答: d.

例題3:vitreous中哪一類的collagen為最主要成份?
a. Type 1 collagen
b. Type 2 collagen
c. Type 7 collagen
d. Type 9 collagen
答: b.