Pseudo phakic visual acuity after extra capsular cataract extraction with posterior chamber intra ocular lens implantation

Abstract

Background: Manual (non phaco) extra capsular cataract extraction with posterior chamber intra ocular lens (ECCE + PCIOL) was commenced in Aminu Kano Teaching Hospital Kano in the year 2001.

Objectives: Firstly to evaluate the pseudo phakic visual acuity and determine the proportion of patients who attained normal vision (6/6 to 6/18) after surgery. Secondly, to determine if there is a statistically significant difference in normal visual outcome between +19 and +21 diopter sphere (the two available powers of) PCIOL.

Patients and methods: The theater register was used to extract names and hospital numbers with type of cataract surgery done on patients from 2001 to 2004. The following categories of patients were excluded; those with associated glaucoma, presence of corneal opacity, traumatic cataracts, secondary cataracts, and patients younger than 40 years. One hundred eyes of 100 patients with age related cataracts, with normal intra ocular pressure, briskly reacting pupils, and accurate four quadrant light projection were selected using simple random number sampling. All patients had manual (non phaco) ECCE. Information extracted from the patients records included age, sex, and visual acuity at presentation and after surgery at 3 months follow up. Visual acuity was measured with either Snellen's or, Illiterate “E” charts at 6 meters. All surgeries were done by the same surgeon.

Results: There were 295 patients who had ECCE+PCIOL. Fifty three patients were excluded due to co existing glaucoma, corneal opacity, anterior chamber IOL and evidence of previous eye trauma. One hundred eyes of 100 patients were selected by simple random sampling from the remaining 242 patients. There were 68 males and 32 females (M: F= 2:1). The patients age ranged between 40 and 80 years, 55% were between the ages of 50 to 60 years. Fifty three eyes had PCIOL +19 diopter sphere (DS) power and 47 had PCIOL +21 DS. Before surgery 15% of the eyes were severely visually impaired (SVI) and 85% were blind. Forty eight percent had normal vision after surgery and this improved to 69% with refraction. Twenty seven percent had post operative vision of less than 6/18 to 6/60. Two eyes remained blind after surgery due to chorioretinal scar involving the macular of the operated eye. The second patient had hypertensive retinal exudates (bilateral, with macular involvement in the operated eye). Two eyes were SVI from persistent pseudo phakic macular edema with vitreous degeneration in both eyes of one of the patient. Normal corrected visual outcome was observed in 37% and 32% of patients with +19DS and +21DS PCIOL, respectively. There was no statistically significant difference in normal visual outcome between PCIOL of +19 and +21 DS using X-squared test. (X²=2.6, p<0.05).