Lens - Introduction, Types of Cataract and Clinical Features MCQs

Monocular Diplopia Monocular diplopia is usually attributable to refractive or media abnormalities. Common causes include uncorrected astigmatism, corneal irregularities, tear film abnormalities, cataract, etc. The hallmark of monocular diplopia from refractive abnormalities is improvement with pinhole. KIDS(pneumonic) Keratoconus/astigmatism Incipient cataract Double pupil/trauma Subluxated lens Reference: kanski, 5 th Edition, Page no. 544.

Wagner's syndrome has an autosomal dominant (AD) inheritance with following features: Vitreous is liquified with condensed membranes. Retina shows narrow and sheathed vessels, and pigmented spots in the periphery. Choroid may be atrophied. Cataract may develop as late complication. Reference : Comprehensive Ophthalmology 7 th ed. – A.K.Khurana, Ch-12 Diseases of retina

Cataracts are recognized as the most common anterior segment complication of RP. The opacity of lens generally happens at the mid stage of the disease course with obvious clinical symptoms and signs, and the major symptom is glare, especially in bright light. As these are complicated cataracts and are posterior subcapsular cataracts the most common prob is that of glare. Reference: parson's 22/e section IV, chapter 20. pg-327-328. RP

The crystalline lens absorbs almost all incident energy to wavelengths of nearly 400 nm. In youth, a very small amount of UV-A reaches the retina, but the lens becomes more absorbing with age. Reference: Khurana Optics 2/e

Accommodation is a dynamic process in which the curvature of the eye's natural lens is temporarily adjusted to improve focus at near or in eyes that are hyperopic (far-sighted). Accommodative convergence described the normal convergence of the eyes in response to accommodation of the lens It is strongest in children, gets weakened with age Reference: Khurana Optics 2/e

Zonular or lamellar cataract is the most common type of congenital cataract associated with diminished vision. A zone in the foetal nucleus is usually affected. Hypocalcemia in pregnancy is an important cause. Reference: Yanoff and Duker 4th edition 415/416

Nuclear cataract usually affects the embryonic nucleus . Rubella in pregnancy is an important cause. In maternal rubella infection, after 6 weeks of gestation , the virus can penetrate the lens capsule causing unilateral or bilateral, dense, nuclear opacities at birth, or they may develop several weeks or months later. Extra information - lamellar/ zonular cataract can also be seen in rubella. The congenital rubella retinitis may present as a salt and-pepper fundus appearance. Reference: Yanoff and Duker 4th edition 415/416

Origin is from surface ecotoderm, not neural ectoderm. Reference: Yanoff and Duker 4th edition/329