Purpose:
Long anterior zonules (LAZ), characterized by zonular fibers that extend more central than usual on the anterior lens capsule, may cause a unique type of intraocular pigment dispersion, and there is question whether there is association with open- and narrow-angle forms of glaucoma. Although one variety of LAZ can occur with late-onset retinal degeneration (L-ORD) resulting from a C1QTNF5/CTRP5 mutation, the etiology of a more common variety not associated with L-ORD and usually detected in people >50 years old, is unknown. Age-related phenomena vs. alternative gene mutation(s) are possible explanations. This study investigated evidence for coexisting developmental anomaly in people with the age-associated LAZ phenotype.
Methods:
As part of a larger investigation of the LAZ trait, African-American LAZ subjects and matched controls had extensive ocular evaluation that included standardized retro-illumination photographic documentation of the crystalline lens through a dilated pupil. For this sub-investigation, the frequency of persistent pupillary membranes (PPM) characterized by iris-to-iris attachment with extension across a portion of the pupil was compared between LAZ cases and controls.
Results:
There were 77 LAZ subjects (mean age=69.3 +/- 9.7 yrs, 48 to 92 yrs; 67 females/10 males) and 76 controls (mean age=67.8 +/- 9.0 yrs, 50 to 93 yrs; 65 females/11 males) in the analysis. For right eyes, 18 of 76 (23.4%) LAZ subjects had PPMs vs. 8 of 76 (10.5%) for controls. Among left eyes, 17 of 76 (22.1%) LAZ subjects had PPMs vs. 8 of 76 (10.5%) for controls. Among LAZ subjects 12 of 75 (16%) had PPMs in both eyes vs. 5 of 76 (6.6%) for controls. Controlling for age, subjects with LAZ were 2.8 times more likely to exhibit PPMs than subjects without LAZ (OR=2.8; 95% CI=1.1 to 6.9; P<0.05). Similar results were found for left eyes.
Conclusions:
LAZ subjects were more likely to have PPMs than controls, which may suggest the presence of anterior segment dysgenesis that may affect multiple intraocular structures.
Keywords: anterior segment • iris • clinical (human) or epidemiologic studies: prevalence/incidence