Contributions of the capsulorrhexis to straylight.
OBJECTIVE
To quantify the effect of the capsulorrhexis on straylight and to determine optimal capsulorrhexis size.


METHODS
Fifty-six pseudophakic eyes with intact capsulorrhexis were included in the study. Straylight was measured with a straylight meter before and after pupil dilation. Capsulorrhexis and pupil diameter were measured and opacity of the anterior capsule was graded (on a scale of 0-5) with the slitlamp. Capsulorrhexis size and opacity were compared with the difference in straylight values between natural and dilated pupils.


RESULTS
The mean capsulorrhexis diameter was 4.5 mm (range, 2.9-6.2 mm). Most anterior capsular rims were opaque in the area of contact with the intraocular lens (62.5% higher than grade 1). Mean straylight before pupil dilation was log(s)=1.25 (range, 0.68-2.13), which increased to 1.46 (range, 0.88-2.22) after pupil dilation, which corresponds to a 62% increase (P <.001). The effect of capsulorrhexis size and opacity on the increase in straylight in scotopic conditions can be quantified by the following formula: Deltas = 19 x (grading of anterior capsular rim) x (fraction of pupil area covered by rhexis).


CONCLUSIONS
The influence of size and opacity of the capsulorrhexis via straylight is described in a quantitative model. Capsulorrhexis size must be greater than 4 mm to prevent functional problems at night.
van der Meulen
Ivanka J E
IJ
Department of Ophthalmology, Academic Medical Center, A2 Room 123.1, Meibergdreef 9, 1100 DD Amsterdam, the Netherlands. i.j.vandermeulen@amc.uva.nl
Engelbrecht
Leonore A
LA
Van Riet
Tom C T
TC
Lapid-Gortzak
Ruth
R
Nieuwendaal
Carla P
CP
Mourits
Maarten P
MP
van den Berg
Thomas J T P
TJ
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019923:Capsulorhexis; D019466:Glare; D006801:Humans; D019654:Lens Implantation, Intraocular; D008027:Light; D008875:Middle Aged; D018918:Phacoemulsification; D019591:Pseudophakia / Q000503:physiopathology*; D011680:Pupil / Q000502:physiology; D012542:Scattering, Radiation; D014792:Visual Acuity / Q000502:physiology