الفهرس 
Anatomical &physiological backgroundOnly 14 pages are availabe for public view
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Abstract
Choroidal neovascular membrane ( CNVM ) represents thegrowth of new, acquired , abnormal blood vessels that originate in the choroid, penetrate Bruch’s membrane and spread beneath the retinal pigment epithelium and / or neural retina (Bressler; et al ,1988).
Choroidal neovascular membrane (CNVM) is a majorcause of visual loss in a variety of macular disorders(Spalton ;et al., 2005).
Age-related macular degeneration is one of the most important conditions associated with choroidal neovascular membrane. Many other conditions, known as non-age related macular degeneration, are also associated with choroidalneovascular membrane. These conditions include (Yanoff ;et al, 1999):
- Pathologic myopia.
- Ocular histoplasmosis syndrome ( OHS)
- Angioid streaks.
- Multifocal choroiditis
- Idiopathic choroidal neovascularization .
- Traumatic choroidal rupture & heavy focal laser.
It has been known that , any pathologic condition that disturb retinal pigment epithelium and / or bruch’s membrane, can result in choroidal neovascularization (Bressler; et al ,1988).
A variety of clinical symptoms suggests the diagnosis of CNVM. However , the diagnosis is confirmed by (Kanski 1999):
a) clinical evaluation of the macula with fundus biomicroscopy , visual acuity testing and amsler grid testing .
b) Fluorescein angiography ( FA )
c) Indocyanine green angiography ( ICGA ) .
d) Optical Coherence Tomography ( OCT).
Current knowledge of molecular events in the pathogenesis of choroidal neovascularization (CNV) has allowed CNV to be targeted with very specific antiangiogenic factors. Targeting VEGF allows a two-hit strategy: antiangiogenesis and antipermeability. VEGF is 50,000 times more potent than histamine in inducingvascular permeability. An important component of decreased vision is the accumulation of subretinal fluid secondary to increased vascular permeability(Ip ;et al, 2008).
Argon Laser Photocoagulation for Treatment of CNVM: Thermal laser ablation of CNV is now rarely used, though may still be suitable for treatment of classic extrafoveal membranes and some cases of PCV and RAP (Kanski; et al,2011).
Photodynamic therapy(PDT) represents an technology for the treatment of neovascular processes affecting the eye and other parts of the body(Donati ;et al, 1999)( Smith; et al. 1999)( Men-ill; et al, 1999).
The basic principle of PDT is the activation of a dye by low-power laser light to induce thrombosis of the neovascular vessels. This can be done with relative ease and safety with regard to the surrounding normal neurosensory retina because of the lower power levels employed in PDT than in photocoagulation(Moshfegi; et al, 1998).
Reichel et al showed managing of occult subfoveal CNVM with transpupillary thermotherapy (TTT). Transpupillary thermotherapy (TTT) is a technique in which heat is delivered to the choroidal and retinal pigment epithelium through the pupil using a modified diode laser. This causes a state of hyperthermia in deep choroidal tissue. Applications of TTT for choroidal tumors have proven this modality. The Authors show this treatment modality for treating occult choroidal neovascularization.Candidates for TTT are patients who have occult CNVM with fairly good visual acuity , in the 20/60 to 20/80 range(Reichel; et al ,1999).
New surgical techniques have been developed for the management of this condition. Early reports of surgical removal of subfoveal choroidal neovascularization have demonstrated limited visual results. Only eyes with intact subfoveal retinal pigment epithelium have demonstrated a significant visual recovery during follow up. Consequently, different innovative surgical approaches including RPE-transplantation, iris pigment epithelium transplantation and macular relocation for themanagement of subfoveal choroidal neovascularization are under investigation(De Juan &Machemer, 1988 ).
The shortage in each individual method in treating the CNVM require continuing investigations to improve the results of these methods and the search for new methods of treatment, and open the door for combined therapy(kansi;et al,2011).