Phthisis bulbi ophthalmology presentation.pptx

corneal trasplantation.ophtaaa

1. Phthisis bulbi

2. Phthisis bulbi is defined as atrophy, shrinkage, and disorganization of the eye and intraocularcontents . Many blind eyes pass through several stages of atrophy and disorganization before progressing to the end stage of phthisis bulbi: Atrophia bulbi without shrinkag e. In this initial stage, the size and shape of the eye are maintained despite the atrophy of intraocular tissues. The following structures are most sensitive to loss of nutrition: the lens, which becomes cataractous ; the retina, which atrophies and becomes separated from the RPE by serous fluid accumulation; and the aqueous outflow tract, where anterior and posterior synechiae develop .

3. Cont… Atrophia bulbi with shrinkage. In this stage, the eye becomes soft because of ciliary bodydysfunction and the progressive diminution of IOP. The globe becomes smaller and assumes a squared-off configuration as a result of the influence of the 4 rectus muscles. The anterior chamber collapses. Associated corneal endothelial cell damage initially resultsin corneal edema, followed by opacification from degenerative pannus , stromal scarring,and vascularization. Most of the remaining internal structures of the eye will be atrophic but recognizable histologically .

4. Cont… Phthisis bulbi In this end stage, the size of the globe shrinks from a normal average diameter of 23–25 mm to an average diameter of 16–19 mm. Most of the ocular contents become disorganized . In areas of preserved uvea, the RPE proliferates, and drusen may develop. In addition, extensive dystrophic calcification of Bowman layer, lens, retina, and drusen usually occurs. Osseous metaplasia of the RPE with bone formation may be a prominent feature. Finally , the sclera becomes markedly thickened, particularly posteriorly .

5. Cont… Phthisis bulbi represents an ocular end stage disease characterized by atrophy, shrinkage, and disorganization of the eyeball and intraocular contents. It is derived from the Greek word phthiein or phthinein , meaning shrinkage or consuming. Atrophy and phthisis bulbi refer to consecutive stages in the degeneration process:

6. Cont… Stage 1 is ocular atrophy without shrinkage, in which there is atrophy of intraocular structures such as the retina and uvea in a normal size or even enlarged eye ( bupthalmos ) such as diffuse atrophy in longstanding glaucoma; Stage 2 is ocular atrophy with shrinkage (aka atrophia bulbi), which refers to atrophy of intraocular structures, plus atrophy of the globe so that it is smaller than normal; Stage 3 is ocular atrophy with shrinkage and disorganization, known as phthisis bulbi

7. Optociliary shunt vessels can be classified as congenital or acquired. Congenital cases are rare. They represent a vascular malformation that connects the retinal and choroidal venous circulations. Acquired causes of optociliary shunt vessels Common Central and hemicentral retinal vein occlusion Optic nerve sheath meningioma Chronic glaucoma Less common Chronic papilledema Optic nerve head drusen Optic nerve glioma Arachnoid cyst of the optic nerve Phakomatoses Diabetic retinopathy

8. Cont… Optociliary shunt vessels are diagnosed on ophthalmic fundus exam, appearing as tortuous vascular loops that start and end on the disc. Flow within these shunts can be documented in indocyanine green angiograms, as well as during the venous phase of fluorescein angiography. They must be differentiated from neovascularization of the disc . Optociliary shunt vessels exhibit a larger caliber and do not cause leakage on FA