Retinoscopy Clinical Hints
- A Retinoscope objectively determines the Sphero-Cylindrical Refractive error and irregular Astigmatism, and also evaluate Opacities and irregularities of the Cornea and Lens.
- Most Retinoscope today use a Streak projection system. This Streak of light is reflected from a Mirror.
- The Streak can be moved in relation to a Convex Lens in the device by way of the Sleeve. This allows the light to leave the device as if it were coming from a point behind the Retinoscope (Plano Mirror setting) which routinely used , or as if it were coming from a point between the examiner and the patient (Concave Mirror setting).
- For Copeland Retinoscopes, the Plano position is with the Sleeve up, while the Welch Allyn Retinoscope is in the plano position with the Sleeve down.
- Normally, the examiner will use their right eye to perform Retinoscopy on the patient’s right eye and their left eye for the patient’s left eye.
- The examiner should align themselves just off-center to minimize lens reflections and to allow the patient to visualize the distance target to relax their accommodation.
- The patient should be instructed( from time to time ) to look at a distance target such as a large Snellen letter (20/200-20/400).
- When doing Retinoscopy, the examiner is attempting to put the far point of the patient’s eye at the plane of the examiner’s pupil.
- When the reflex shows “against” motion, the far point plane lies between the patient’s eye and the examiner’s eye, indicating Myopia.
- When the reflex shows “with” motion, the far point lies outside the interval between (The patient’s eye and the observer’s eye), indicating Hyperopia, emmetropia or mild myopia.
Let’s make a question to be simply understood, if you obtain “with motion” during Retinoscopy. Where is the far point of the patient ?
- In front of the peep hole.
- At the peep hole.
- Beyond the peep hole.
Answer: Beyond the peephole. As u r dealing with Hypermetrope!
- The goal of Neutralization is to have the light reflex of the patient’s far point at the peephole.
- The light at the patient’s pupil fills the entire space at once when neutrality is reached.
- “With” motion requires more plus to be added to the prescription to move the far point to neutralization.
- “Against” motion means that the far point is in front of the peephole. Therefore, more minus must be added to move the far point to neutralization.
Retinoscopy step by step :
- ROOM LIGHTS OFF
- Ask patient to look at a non-accommodative target distance (green duochrome).
- Compensate your working distance (if you work at 2/3m, add +1.50 D DS).
- Fog fellow eye with a high plus powered lens to prevent accommodation.
- Aim to be as close to the patient’s visual axis without obscuring their fixation target.
- If your head gets in the way, they are likely to look at it and start accommodating.
- Ask the patient to tell you if this happens.
- Check retinoscopy reflex:
- Identify axis of astigmatism from movement of retinoscopy light as sweep across eye.
- Neutralize reflex in one meridian with DS lenses.
- If reflex is (with) then add PLUS, if (against) then add MINUS.
- When point of reversal is reached in one meridian add cylindrical lenses to neutralize in the other meridian.
- Use Plus or minus cylinders and Be consistent either work with plus or with minus cylindrical lenses.
- If using PLUS cylindrical lenses, correct the most MINUS meridian .
This is identified by:
- If both reflexes are against, then it is the slower reflex.
- If one is with and one against, then it is the against reflex.
- If both reflexes are with, then it is the faster reflex.
15.If using MINUS cylindrical lenses, correct the most PLUS meridian.
This is identified similarly:
- If both reflexes are against, then it is the faster reflex.
- If one is with and one against, then it is the with reflex.
- If both reflexes are with, then it is the slower reflex.
- Consider media opacity:
- Optimize illumination
- Check patient not accommodating on your head.
- Consider high refractive error:
- Use large steps, e.g. ± 5.00 DS or ±10.00 DS.
- Consider keratoconus:
- If swirling or scissoring reflex or oil drop sign.