A refractive surprise can be defined as the failure to achieve the intended postoperative refractive target or the presentation of unexpected and, unwanted post-operative refractive error. It can cause anisometropia or dominance switch and is a source of patient dissatisfaction due to unmet expectations.The best way to manage refractive surprise is to prevent it. The 2017 NICE guidelines on the management of cataracts provide advice on prevention of refractive surprise through accurate biometry, A-constant optimisation, intraocular lens (IOL) formula selection and avoiding wrong lens implant errors.Benchmark standards for NHS cataract surgery dictate that 85% of eyes should be within 1 dioptre (D) and 55% within 0.5D of target spherical equivalent refraction following surgery.

Aim(s) of the Research:

1. detection of refractive surprises using autorefractometer, and corneal topography.
2. treatment of the resulting refractive error surprises.

Inclusion Criteria:

All adult patients scheduled for cataract surgery with:

• Symptomatizing patients with postoperative spherical error of more than 1 diopters.
• Symptomatizing patients with postoperative cylindrical error of more than 1 diopters.
• Symptomatizing patients with uncorrected distant visual acuity less than 6/24
• Symptomatizing patients with corrected distant visual acuity of less than 6/12
• Clear cornea. 6. Uneventful surgery.

Exclusion Criteria:

• Patients with complicated cataract.
• Raised intraocular pressure (IOP).
• Patients with pathologies of the posterior segment of the eye.
• Other causes of diminution of vision.