Abstract
Purpose :
EVALUATE THE RELATIONSHIP BETWEEN PREOPERATIVE AXIAL LENGTH AND MYOPIC SHIFT OVER 3 YEARS AFTER CONGENITAL CATARACT SURGERY WITH PRIMARY INTRAOCULAR LENS IMPLANTATION IN THE NATIONAL INSTITUTE OF OPHTHALMOLOGY OF PERU 2007 - 2011
Methods :
This was an analytical retrospective cohort study. Patients younger than 4 years of age who underwent cataract surgery with primary IOL implantation, primary posterior capsulorhexis, and anterior vitrectomy were included. Patients who had cataracts of another etiology or other associated ocular pathology were excluded.
Information on immediate refraction (spherical equivalent) was taken after surgery (1 to 5 months) and after 3 years, then the myopic shift was calculated at this time.
The axial length was measured and assigned into two groups (> 21.5 mm, and < 21.5 mm) and compared to the myopic shift, visual axis obscuration, laterality of cataract, age at surgery and follow up time. With this, a sample size of 76 patients was estimated, with a power of 80%, a 95% confidence interval and a 5% error.
Results :
The mean myopic shift at 3 years in all patients was 3.6 D (SD: 2.3 D), but in group 1 (>21.5 mm) it was 3.2 D (SD: 3.3) and in group 2 (<21.5 mm) of 3.9 D (SD: 3.2) (p = 0.359). In bilateral cataracts only was 2.6 D (SD: 2.0) and 3.4 D (SD: 1.8) respectively (p = 0.098).In bilateral cataracts, the mean myopic shift was 3.0 D and in unilateral cataracts was 6.3 D (p = 0.001). In this type of cataract a greater myopic shift was observed in both groups [6.7 D (SD: 6.7) and 6.1 D (SD: 6.3) p = 0.882)].
It was observed that the myopic shift had a tendency to have a direct relationship with the time after the surgery being 1.95 D (at 1 to 2 years), 3.46 D (at 2 to 3 years) and 3.84D (at 3 years).
Conclusions :
We did not find relationship between the initial axial length and the myopic shift in all patients. Unilateral cataracts had a greater myopic shift over 3 years.
But we saw in the bilateral cataract group a tendency to greater myopic shift with smaller axial lengths; so we should investigate more this variable in this group.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.