Pinhole visual acuity test

 

I.    List indications and contraindications

A.    Indications

1.    Estimate the best corrected visual acuity

2.    Evaluating potential visual acuity of patients with cataract and other opacities of the ocular media

B.    Contraindications

1.    Very dense cataract

2.    Patient inability to understand and perform the test

 

II.    List the alternatives to this procedure

A.    Manifest Refraction

B.    Potential acuity meter

C.    Laser interferometry

D.    Entoptic phenomena

E.    Critical flicker/fusion frequency

 

III.    Describe the instrumentation and technique (See Figure 1)

A.    Premise

1.    Pinholes increase depth of focus and decreases light-scattering effect of residual refractive error, corneal and/or lenticular opacities

2.    The illuminated chart helps compensate for reduced light from pinhole

B.    Procedure

1.    Pupils may be dilated pharmacologically

2.    Usually the examination room is darkened

3.    Pinhole ocular occluder is placed over the patient’s eye with or without correction in place

4.    Illuminated visual acuity chart or near card is presented

 

IV.    Describe the considerations in interpretation of this diagnostic procedure

A.    Predictive ability is variable

B.    May underestimate visual acuity in dense cataracts and macular disease

C.    May overestimate best corrected visual acuity

 

Additional Resources

1.    AAO, Basic and Clinical Science Course. Section 11: Lens and Cataract, 2013-2014.

2.    Gus PI, Kwitko I, Roehe D, Kwitko S. Potential acuity meter accuracy in cataract patients. J Cataract Refract Surg 2000 Aug; 26(8):1238-1241.

3.    Uy HS, Munoz VM. Comparison of the potential acuity meter and pinhole tests in predicting postoperative visual acuity after cataract surgery. J Cataract Refract Surg 2005 Mar;31(3):548-52.

4.    Hofeldt AJ, Weis MJ. Illuminated near card assessment of potential acuity in eyes with cataract. Ophthalmology 1998 Aug; 105(8):1531-6.