Macular Disorders, Retinal Dystrophies, and Vitreal Disorders MCQs

Rather the vessles become thin and attenuated in retinitis pigmentosa. This is most consistent sign in RP also. Reference: parson's 22/e section IV, chapter 20. pg. 328.RP

Ornithine aminotransferase deficiency (also known as gyrate atrophy of the choroid and retina) is an inborn error of ornithine metabolism, caused by decreased activity of the enzyme ornithine aminotransferase. Biochemically, it can be detected by elevated levels of ornithine in the blood. Clinically, it presents initially with poor night vision, which slowly progresses to total blindness . It is believed to be inherited in an autosomal recessive manner. Research suggests there can be some adverse effect on muscles and also the brain. The cause of this is somewhat unclear but may relate to very low levels of creatine often found in this population. Treatment may include vitamin B6, lysine or dramatic dietary change to minimize arginine from patient's diet . Reference: Kanski, 7th Edition, Pg no. 473.

Ocular associations of retinitis pigmentosa include myopia, primary open-angle glaucoma, microphthalmos, conical cornea (keratoconus) and posterior subcapsular cataract. Reference: Comprehensive Ophthalmology 7 th edition – A.K.Khurana, Chapter-12 Diseases of retina.

Choroidal neovascularization (CNV) consists of a blood vessel complex that extends through Bruch membrane from the choriocapillaris into the sub-retinal pigment epithelium (type 1) or subretinalspace (type 2). Age related macular degeneration is the most common causative association, followed by myopic degeneration. Causes of choroid neovascularization(CNV): Degenerative conditions - Age related macular degeneration, myopia, angioid streaks. Inflammatory or infectious conditions - Histoplasmosis, sarcoidosis, multifocal choroiditis Choroidal tumors Choroidal rupture Laser photocoagulation Idiopathic Hypermetropia does not cause CNV. Reference: Kanski, 7th Edition, Pg no. 462.

Although epiretinal membrane may be associated with trauma, retinal venous occlusion, and uveitis, it is most commonly associated with posterior vitreous detachment. Reference: Kanski 8th edition/618

Fundus flavimaculatus is a flecked retinal dystrophy affecting both eyes and appears usually in the third or fourth decade of life. White or yellowish white deep retinal flecks resembling fish tails with fuzzy outlines as seen with the ophthalmoscope are characteristic. Reference: Parson’s diseases of the eye, 23 rd edition, Chapter 17 - Diseases of retina and vitreous.

Refsum's syndrome is characterised by retinitis pigmentosa, peripheral neuropathy and cerebellar ataxia. Reference: Comprehensive Ophthalmology 7 th edition – A.K.Khurana, Chapter-12 Diseases of retina.

Laurence-Moon-Biedl-Bardet syndrome is characterised by retinitis pigmentosa, obesity, hypogenitalism, polydactyly and mental deficiency. Reference: Parson’s diseases of the eye, 23 rd edition, Chapter 17 - Diseases of retina and vitreous.