Eye TEsts

Eye Tests:

Required Tests :

• Refraction
o best corrected spectacle vision is determined using a phoropter and a snellen vision chart. In general,best corrected vision of less than 20/40 is considered to represent a level of functional disability at which the risk benefit ratio favours performing cataract surgery.

• Sliplamp exam
o a slit lamp is used to examine the eye and diagnose the presence of the cataract

• Dilated fundus test
o Pupil is dilated using eyedrops.
o Eyes may remain dilated for 6 to 12 hours
o The retina can be examined very well and all the way out to the periphery after dilation dilation of pupil.
o It is important to rule out retinal problems like macula degeneration before proceeding to cataract surgery.

• Keratometry
o A keratometer measures the curvature of the cornea
o Use to calculate the power of the intraocular lens implant

• A –scan
o Ultrasonically measure the length of eye
o To calculate the power of the intraocular lens that would be implanted during cataract surgery.\

Optional Tests :

• Constrast Sensitivity
o Pelli-Robson Test
 measures contrast sensitivity using a single large letter size (20/60 optotype), with contrast varying across groups of letters.
o Bailey-Lovie Chart
 measure contrast sensitivity. In this chart all letters have the same contrast but their size varies (as in visual acuity charts).

• Glare Disability Test
o The vision is measures using the low, medium or high light settings of the BAT
 Brightness Acuity Tester
 Stimulates 3 bright light conditions :
 Direct overhead sunlight
 Partly cloudy day
 Bright overhead commercial lighting

• Potential Acuity Meter (PAM)
 Projects a small eye chart through the cataract directly onto the macula
 Fairly accurate prediction of postoperative vision.