Remnants of the anterior tunica vasculosa lentis and long anterior lens zonules

Anterior segment phenotypic changes in late-onset retinal degeneration with Ser163Arg mutation in CTRP5/C1QTNF5

PURPOSE

Late-onset retinal degeneration (L-ORD) is a rare retinal dystrophy with anterior segment (AS) abnormalities, including long anterior zonules (LAZ) and iris atrophy. This investigation evaluates AS changes in a L-ORD cohort.

METHODS

Prospective, longitudinal study including L-ORD individuals (Ser163Arg) with ocular exam and standard slit-lamp photographs between 2011 and 2022. AS images were merged and assessed for LAZ number and zonule-free zone (ZFZ) radius. Further clinical findings such as iris atrophy patterns were reported descriptively.

RESULTS

Twelve eyes of 6 patients (4 males, median age = 60.5 years) were included, showing a median of 160 (11-372) LAZs, mainly localized superiorly (39%) and inferiorly (24%). There was a high inter-ocular correlation (rs = 0.94, p < 0.01), no difference in LAZ count between eyes (p = 0.82), and an inverse relationship between LAZ and age (r =  - 0.82; p < 0.05). The ZFZ had median 2.1 mm (1.3-5.4), with no inter-ocular difference (p = 0.31). Iris transillumination defects occurred in 11/12 eyes, with 4 major patterns identified: pupillary ruff rarefaction (10/12), patchy atrophy (6/12), notched defects (6/12), and radial streaks (2/12). In a short-term follow-up of 5.9 years, 4 eyes showed a reduction in LAZ count to median 139.5 (67-169) (p = 0.50) and a concomitant increase in ZFZ measurement to median 2.2 (1.7-2.6) (p = 0.17).

CONCLUSION

This study confirms symmetric LAZs count and ZFZ in L-ORD, with ZFZ measurements smaller than in previous cohorts. A reduction in LAZs count and an increase in ZFZ with age were suggested longitudinally, yet findings need further evaluation as follow-up was limited to two cases.

Long anterior lens zonules with retinal stripes: a case report

Background

Long anterior lens zonules   (LAZs) is a rare disease that was mostly conducted among African Americans. Through the observation of a Chinese patient, we discoverd that the disease may show different characteristics in Asians.

Case presentation

A patient with vision loss due to a macular hole was found to have several special clinical signs during vitrectomy combined with phacoemulsification and intraocular lens implantation surgery in our hospital, including radially oriented lines on the anterior capsule with pigment, a shallow anterior chamber, slightly high intraocular pressure, and radial retinal stripes in the peripheral retina. Finally, he was diagnosed with long anterior lens zonule syndrome.

Conclusion

Clinicians need to pay more attention to the rare disease LAZs. It is important to tear the appropriate size of the anterior capsule so as to avoid radial capsular tearing and intraocular lens dislocation.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12886-022-02496-7.

Long Anterior Zonules and Angle Closure Disease

PRCIS

Angle closure disease was present in 59.3% of eyes with long anterior zonules (LAZ). The cause is multifactorial including a thick anteriorly positioned crystalline lens, shorter axial length, and increased lens thickness to axial length factor.

PURPOSE

To study the profile of eyes with LAZ presenting in a glaucoma clinic in a tertiary eye care centre and understand the pathogenesis of angle closure disease in these eyes.

METHODS

This was a retrospective cross-sectional study.All patients with LAZ seen from January 2014 to December 2018 were included. Demographic and clinical characteristics were noted. LAZ eyes (177 eyes of 177 patients) were compared with an equal number of age and sex-matched controls. LAZ was defined as radially oriented zonular fibers (both pigmented and nonpigmented), extending central to the normal zonular termination zone on the anterior lens surface >1 mm beyond their usual insertion of 1.42±0.24 mm from the lens equator onto the mid peripheral zone or central to it, as seen on slit-lamp examination, following pupillary dilation by a single examiner. Glaucoma was defined according to the International Society for Geographical and Epidemiological Ophthalmology classification. The following biometric parameters were compared: anterior chamber depth (ACD), axial length (AXL), lens thickness (LT), lens position (LP=ACD+0.5×LT), relative lens position (RLP=LP/AXL); lens thickness to axial length factor (LAF=(LT/AXL)×10). LAZ eyes without angle closure disease were also compared with controls.

RESULTS

Mean age of patients with LAZ was 64.8±8.1 years. Of these, 63.3% were females. Angle closure disease was present in 59.3% (105/177) patients. Majority of these eyes were primary angle closure suspects (PACS) (53.3%, n=56). Significant differences were found between LAZ eyes and controls for LT (4.8±0.38 mm vs. 4.49±0.40 mm, P<0.0001), ACD (2.68±0.39 mm vs. 3.0±0.32 mm, P<0.0001), AXL (22.37±0.79 mm vs. 22.94±1.1, P<0.0001), LAF (2.14±0.19 vs. 1.96±0.21, P<0.0001), and LP (5.07±0.37 vs. 5.3±0.25, P<0.0001).

CONCLUSIONS

Angle closure was present in more than half the eyes with LAZ. Majority of these eyes were PACS or had primary angle closure. LAZ eyes had a thicker lens, shallow AC, a shorter axial length and an increased LAF as compared with age and sex matched normal controls. The presence of LAZ may be an indicator of increased risk for angle closure.

Longitudinal phenotypic study of late-onset retinal degeneration due to a founder variant c.562C>A p.(Pro188Thr) in the C1QTNF5 gene

Background: Late-onset retinal degeneration (L-ORD) is a rare autosomal dominant retinal dystrophy related to C1QTNF5 gene variants.Materials and methods: Twenty-six patients (21-81 years) with L-ORD due to c.562C>A p.(Pro188Thr) with a mean follow-up time of 8 years (range 1-37 years) underwent an extensive ophthalmic work-up.Results: Best-corrected visual acuity (BCVA) and visual fields were maintained up to 50 to 55 years (n = 8), with a gradual decline, but conservation of functional central vision between 55 to 65 years (n = 15), followed by a steep decrease in overall visual function beyond 65 years (n = 9). Classic anterior segment findings in L-ORD of abnormally long, anteriorly inserted lens zonules were absent in most patients (n = 24/26). In contrast, findings of iris transillumination and sphincter pupillae atrophy with poor dilation were novel. Patients presented with three completely different initial fundus phenotypes: adjoining pavingstone-like atrophic patches (type 1) (n = 6/20); tiny yellow-white subretinal dots (type 2) (n = 8/20); or larger yellow, thick, round sub-RPE drusenoid deposits (type 3) (n = 4/20). Two patients had a mixed phenotype. Although different in presentation phenotype, patients eventually all progressed to a common panretinal atrophy with diffuse intraretinal pigment migration beyond the age of 65. Progression pace, and thus visual prognosis, differed depending on presentation phenotype. Specifically, type 2 appears to have a more benign course.Conclusions: Phenotypic analysis showed three distinct presenting phenotypes with a considerable intrafamilial variability both in age of onset of clinical signs and in disease progression, with a fair visual potential (>20/40) until the seventh decade.Abbreviations: L-ORD: Late-onset retinal degeneration; C1QTNF5: complement 1Q tumor necrosis factor 5; OCT: Ocular coherence tomography; BCVA: Best-corrected visual acuity; RPE: Retinal pigment epithelium; ffERG: Full-field electroretinography; IRD: Inherited retinal dystrophy; CNV: Choroidal neovascularization; LAZ: Long anteriorly inserted zonules; AMPK: AMP-activated protein kinase; IOP: Intraocular pressure; cSLO: confocal scanning laser ophthalmoscopy; BAF: Blue light autofluorescence; NIR-AF: Near-infrared autofluorescence; NIR-R: Near-infrared reflectance; RF: Red-free; SD-OCT: Spectral domain ocular coherence tomography; HRR: Hardy-Rand-Rittler pseudo-isochromatic plates; AS: anterior segment; UBM: ultrasound biomicroscopy; PCR: Polymerase chain reaction; SNP: Single nucleotide polymorphism; VEGF: Vascular endothelial growth factor; IZ: Interdigitation zone; EZ: Ellipsoid zone; ELM: External limiting membrane; LP: Light perception; AMD: Age-related macular degeneration; SFD: Sorsby fundus dystrophy.

Phacoemulsification in eyes with long anterior zonules

PURPOSE

To study the safety of phacoemulsification in eyes with long anterior zonules (LAZs).

SETTING

Institute.

DESIGN

Retrospective interventional case series.

METHODS

All patients with clinically proven LAZs who had undergone phacoemulsification by a single surgeon from January 2014 to December 2018 were included. All cases of LAZs with cataract extraction by procedures other than phacoemulsification or combined with any other ocular surgery were excluded. Sixty-five eyes of 52 patients were analyzed. Phacoemulsification with capsulorhexis that involves sacrificing the LAZs was performed. The primary outcome measures were the incidence of capsulorhexis extension or the need to rescue intraoperatively and the rate of intraoperative complications. Secondary outcomes assessed were the percentage of eyes within ±0.5 diopters (D) and ±1 D of the target refraction.

RESULTS

Sixty-five eyes (52 patients) were analyzed; the mean age of patients was 67.3 ± 7.4 years. The successful completion of an adequately sized capsulorhexis without extension or rescue was seen in 100% of cases. The incidence of intraoperative complications was 1.5% (posterior capsular rupture in 1 eye). The mean postoperative corrected distance visual acuity was 0.05 ± 0.1 (logarithm of the minimum angle of resolution) at a mean of 26.8 ± 7.6 days. The mean spherical equivalent was -0.15 ± 0.7 D. Eyes within ±0.5 D and ±1.00 D of the target refraction were 77% and 94%, respectively.

CONCLUSIONS

Phacoemulsification in eyes with LAZs can be safely performed through an adequately sized capsulorhexis by sacrificing, ie, cutting or breaking, the anteriorly inserted zonules 360 degrees without significant intraoperative complications.

Long Anterior Lens Zonules and Intraocular Pressure

Purpose

To investigate the relation between intraocular pressure (IOP) and the idiopathic long anterior zonule (LAZ) trait.

Methods

Patients presenting for primary eye care were examined for LAZ, identified as radially oriented zonular fibers with central extension >1.0 mm beyond the normal anterior lens insertion zone (estimated via slit lamp beam length). Ocular, systemic health, and lifestyle data were collected via comprehensive exam and questionnaire. Multivariate regression was used to assess the relationship between IOP (Goldmann) and LAZ.

Results

There were 2169 non-LAZ and 129 LAZ subjects (mean age: 49.8 ± 15.0 vs. 62.6 ± 10.2 years; 63.6% vs. 76.0% female; 83.2% vs. 91.5% African American). Right eyes with >trace LAZ (n = 59 of 110) had higher unadjusted mean IOP than control eyes (16.4 ± 3.3 vs. 15.0 ± 3.3 mm Hg, P = 0.005), and with control for numerous factors, LAZ eyes had an average IOP of approximately 1.3 ± 0.4 mm Hg higher (P = 0.003) than non-LAZ eyes. Final model covariates included sex (P = 0.001); spherical-equivalent refractive error (D; P < 0.0001); body mass index (kg/m²; P < 0.001); presence of diabetes (P < 0.001); having >high school education (P < 0.001); systolic blood pressure (mm Hg; P < 0.0001); being an ever smoker (P = 0.006); and having history of any site cancer (P = 0.01).

Conclusions

The LAZ trait, with potential prevalence near 2%, was associated with a higher IOP. This observation is consistent with the hypothesis that the trait is a marker for underlying mechanisms that elevate glaucoma risk.

Morphologic Patterns Formed by the Anomalous Fibers Occurring Along the Anterior Capsule of the Crystalline Lens in People With the Long Anterior Zonule Trait

People with the long anterior zonule (LAZ) trait, which may have prevalence near 2%, have zonular fibers that extend more central than usual along the anterior capsule of the crystalline lens. The anomalous fibers can be observed in vivo with clinical slit lamp biomicroscopy after pharmacologic pupil dilation, and although minimally studied, the LAZ trait may have importance to glaucoma, retinal degeneration, and cataract surgery. To further characterize LAZ morphology, a custom computer program was used to trace LAZ fibers seen on retro-illumination photos acquired during previous study at an academic, urban eye care facility in Chicago, IL. There were 59 African-Americans (54 female; median age = 70 years, 53-91 years) included in the analysis. After initial review of the zonule tracings, we identified three basic LAZ patterns. We called one pattern (47% of right eyes) a "non-segmental LAZ pattern," which was predominated by fibers that could be visually traced to the dilated pupil border where they became obscured by the iris. Another pattern (35% of right eyes), the "segmental LAZ pattern," was predominated by fibers that appeared to terminate abruptly without detectable extension to the pupil border. The third pattern (18% of right eyes), the "mixed LAZ pattern," had a more equivalent mixture of the other two fiber morphologies. Compared to the "non-segmental" group, the "segmental" LAZ eyes had smaller central zonule-free zones (P < 0.0001), and they tended to exhibit fewer LAZ fibers (P = 0.07). These data improve understanding of LAZ clinical anatomy and may be helpful to future investigation. Anat Rec, 300:1336-1347, 2017. © 2017 Wiley Periodicals, Inc.