Hirschberg test measures?
Ans. (a) StrabismusRef: A.K. Khurana 6th ed. /344-58 Classification of Squints (Strabismus)LATENT SQUINT/HETROPHOR1A* A condition in which the tendency of eyes to deviate is kept latent by fusion. Therefore when the influence of fusion is removed the visual axis of one eye axis of one eye deviates away (Orthophoria is a condition of perfect alignment of two eyes)* Types Esophoria is a tendency to converge# Exophoria is a tendency to diverge# Hyperphoria is a tendency to deviate upwards# Hypophoria is a tendency to deviate downwards# Cyclophoria is a tendency to rotate around A - P axis* Evaluation# Refraction# Uncover test (tells about present & type of hetrophoria)# Maddox rod test (amount of hetrophoria in degrees)# Maddox wing test (amount of phoria for near distance i.e. 33 cm)* Treatment:# Refraction# Occlusion therapy (in presence of amblyopia)# Orthoptic exercise# Operative correction# Prism correction for remaining error.MANIFEST SQUINT (HETEROTROPIA)ComitantIncomitant* Amount of deviation in squinting eye remains constant (unaltered) in ail directions of gaze & there is no limitation of ocular movements.* Manifest squint in which amount of deviation varies in different directions of gaze.* Types* Types# Alternating squint: when one eye fixes, the other eye deviates & either of the eyes can adopt fixation alternately & freely# Esotropia (Convergent squint)# Exotropia (Divergent squint)# Hypertropia (Vertical squint)# Paralytic squint# "A" & "V" pattern hetrotrophias# Special ocular motality defects# Clinical presentation: is diplopia, confusion, nausea, vertigo & ocular deviation with restriction of eye movements, compensatory head posture & false projection & orientation, loss of stereoposis, normal visual acuity & no amblyopia.* Evaluation* Evaluation# Refraction, visual acuity, ocular motality# Direct cover test (confirms the presence of manifest squint)# Alternate cover test (reveal whether the squint is U/L or alternate and to differentiate concomitant squint from paralytic squint).# Estimation of angle of deviation.# Hirschberg corneal reflex test: Roughly the angle of squint is 15deg and 45deg when the corneal light reflex falls on the border of pupil & limbus respectively. The premise is that every millimeter of deviation from centre of pupil is equal to 7deg (15A)# All tests of comitant squint# Diplopia carting# Hess screen test# Forced duction test* Treatment of cause, diplopia (by occlusion), surgery (if no recovery in 6 months).
Strabismus
Glaucoma
Cataract
Refractive error
Strabismus - Definition and Evaluation