Taiwan Journal of Ophthalmology · 4 authors, 3 centres
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This review summarizes rare congenital lens shape anomalies including lens coloboma, lenticonus, lentiglobus, and microspherophakia. It details their etiology, genetics, clinical presentations, and management strategies, emphasizing the importance of genetic testing and multidisciplinary care. The paper provides a comprehensive overview for clinicians to recognize and treat these conditions, which often present with visual impairment and systemic associations.
**Background:** Congenital anomalies of lens shape are rare conditions that include lens coloboma, anterior and posterior lenticonus, lentiglobus, and microspherophakia. These anomalies can cause varying degrees of visual impairment and may be associated with ocular or systemic manifestations. This review aims to summarize the etiology, genetics, clinical presentations, management, and outcomes of each condition.
**Methods:** A literature search was performed on PubMed, Google Scholar, and Cochrane databases using specific search terms for each anomaly. Individual case reports and very small sample size studies were excluded unless they presented novel findings. Review articles and studies with larger sample sizes and surgical outcomes were included. Each lens anomaly was studied and reviewed separately.
**Key Results:** - **Lens coloboma:** Characterized by notching of the lens equator, most commonly inferiorly. It results from defective zonular development. Genetics involve autosomal dominant inheritance (most common), with key genes SHH and PAX6. Management includes refractive correction and surgical intervention with capsular tension rings or Cionni rings for cataract extraction. - **Lenticonus:** Anterior lenticonus is bilateral and associated with Alport syndrome (mutation in COL4A3, COL4A4, COL4A5). Posterior lenticonus is usually unilateral, sporadic, and presents with a conical posterior protrusion. Surgery is challenging due to fragile capsule; PC defect noted in 44% of cases in one study. Management includes glasses and surgery with careful capsulorhexis. - **Lentiglobus:** Rare, involves bulging of the entire lens surface. Posterior lentiglobus is more common, often unilateral and isolated. Surgery requires careful handling of the floppy posterior capsule; optic capture of scleral or iris-fixated IOLs is preferred. - **Microspherophakia:** Increased anteroposterior diameter and reduced equatorial diameter. Associated with Weill-Marchesani syndrome (ADAMTS family genes), Marfan syndrome (FBN1), and others. Management includes refractive correction, and surgery for lens dislocation or glaucoma. In a retrospective study, 51% of 159 eyes had glaucoma. Lensectomy may help control glaucoma, but results vary. - **Other anomalies:** Double lens syndrome and anterior megalophthalmos are extremely rare. Anterior megalophthalmos presents with megalocornea and large anterior segment; surgery is challenging due to cavernous AC and decreased endothelial cell count.
**Clinical Implications:** Genetic testing is valuable for defining genotype-phenotype correlations. Visual rehabilitation requires a multidisciplinary approach. Surgical planning must consider zonular status, capsule fragility, and potential for amblyopia. Timely intervention can prevent long-term complications like amblyopia and glaucomatous damage.