Dynamic retinoscopy

Dynamic retinoscopy

• 2.
   The methodby which you determine the patient’s neat point  It defines the patient’s accommodative posture  It is primarily used to confirm suspected cases of accommodative dysfunction
• 3.
   In dynamicretinoscopy the patient is instructed to fixate a letter, or other objects in the plane of retinoscope  No working distance lens is added or to substract from the findings
• 4.
   Same movementas with static  With: eye conjugate to a point either behind the eye or behind the retinoscope  Against: eye conjugate to a point between the eye and the retinoscope  Neutrality: eye conjugate with the retinoscope
• 6.
  Monocular Estimate Method We neutralizes the reflex of the eye while the patient accommodates to fixate a target at near (usually at 40cm)  With motion: Lag of accommodation --- Add PLUS  Against motion: Lead of accommodation ---Add MINUS
• 7.
   The MEMcard should be attached to the retinoscope with the beam of the retinoscope passing through the hole in the center of it( see Figure 4-16).  The test is performed under normal room illumination.  The patient should wear his habitual near correction.  The test is performed under binocular viewing conditions.
• 8.
   The examineris seated slightly below the patients eye level so the patients eye are in a moderate downward gaze when looking at the target as would occur when reading  Use patient’s correction for distance or a tentative near correction ▪ Place the target at their working distance ▪ Adults: usually 40 cm ▪ Children: use Harmon’s distance ▪ Room illumination should be dim but with target illuminated ▪ Keep desired testing distance consistent ▪ Remain as close to the patient’s line of sight as possible when neutralizing
• 9.
   While thepatient is reading, quickly guide the streak across the patient’s right eye and evaluate the reflex for with or against motion or for neutrality. Be sure to observe the reflex in the center of the pupil rather than at the edge.  Estimate the dioptric value required to neutralize the observed motion (With-plus; Against-minus).
• 10.
   Nott Method:clinician moves toward and away from the patient until neutrality is seen (can be performed in or out of phoropter)  Against motion: move closer to the patient  With motion: move further away from patient
• 11.
   Results  Expected ▪Non-presbyopes: Lag of +0.50D to +0.75D when tested at 40cm ▪ Presbyopes: accommodation ability declines, increasing expected lag of accommodation (dynamic ret is an accepted form ofTNA determination) ▪ Absolute presbyopes: expected lag is +2.50D at 40cm
• 12.
   High Lag(>+0.75D) ▪ Accommodative dysfunction: insufficiency, fatigue, paresis, infacility ▪ Presbyopia or pre-presbyopia ▪ Uncorrected or under corrected hyperope ▪ Over minused ▪ Inaccurate results: patient not keeping the target clear during the test and so not accommodating
• 13.
   High Lag(+2.50D) ▪ Uncorrected or under corrected hyperope ▪ Presbyopia ▪ Inaccurate results: patient not keeping the target clear during the test and so not accommodating
• 14.
   Low lagor lead of accommodation (<+0.25D) ▪ Spasm of accommodation: pseudomyopia ▪ Uncorrected or under corrected myopia  Other abnormal ▪ Fluctuation of reflex also often indicates a near imbalance or accommodative spasm
• 15.
   Sources oferror  Same as those with static: scissors, small pupils, dim media (cataracts, etc.)  More sensitive to physical arrangement for the measurement (distance), instructions given and patient’s cooperation  Changes in patient’s fixation or accommodative level (often related to failure to understand task or to cooperate)
• 16.
  OTHER METHODS  Sheardsmethod  Taits method  Bell retinoscopy  Low-neutral and high-neutral method  Binocular crossed cylinder  Book retinoscopy  Near retinoscopy (Mohindra)
• 17.
   Near retinoscopydiffers from other forms of dynamic retinoscopy coz It is performed in complete darkness, the only illumination in the room being supplied by the retinoscope