Journal article Open Access

A Rule of Astigmatism in Pediatric Subluxated Crystalline Lens

David Ran MD PhD; Berger Ori, Bsc; Cohen Evelyne CO; Karshai Ilana CO; Mechoulam Hadas MD; Anteby Irene MD


Background: Crystalline lens subluxation leads to refractive error typically resulting in myopia and astigmatism. Repeated refraction is mandatory. Retinoscopy is challenging due to phaco/iridodonesis and distorted reflex. This study explored simplified rule of thumb to help determining the correct refraction. We postulated that the expected axis of astigmatism should be parallel to the direction of subluxation.

Methods: We performed a retrospective study of patients (<19 years old), with a subluxated crystalline lens who underwent lensectomy without intraocular lens implantation, at Hadassah University Medical Center between 1980 and 2016. Traumatic cases were excluded. In each case, the correlation between the axis of astigmatism and direction of subluxation was evaluated.

Results: Forty-three eyes were included. The average age was 67.40 (range 10 to 230) months. The average pre–op astigmatism (-3.90D, range -0.75 to -8.75D) was reduced significantly after lensectomy (-0.68D, range -0.5 to -2D). The average pre–op spherical equivalent (SE) was myopic (-5.93D, range -18.75 to +17D). In each direction the pre-op axis of astigmatism was found to be in 93.33% cases horizontal in superior; 76.92% oblique in superotemporal; 100% vertical in temporal; 100% oblique in infero-temporal; 100% horizontal in inferior; 100% vertical in nasal; 66.67% oblique in superonasal, subluxations. Totally, 86% of measured axis were inside those expected ranges in all directions.  

Conclusion: We found a high correlation between the direction of subluxation and the astigmatic axis before surgery for pediatric lens subluxation. We postulate that the high and irregular astigmatism in subluxation is mainly lenticular. As a rule of thumb, the astigmatic axis is expected to be parallel to the direction of subluxation.

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