Microspherophakia is a congenital malformation characterized by a spherical lens shape with increased anteroposterior diameter and decreased equatorial diameter. It usually occurs bilaterally.
The equatorial diameter of the lens is normally about 9–9.5 mm, whereas in microspherophakia it is reduced to about 6.8–7.5 mm (anteroposterior diameter 4.5–4.9 mm). An equatorial diameter of 8 mm or less indicates microspherophakia. Due to the increased anteroposterior diameter, the entire circumference of the lens equator becomes visible under full mydriasis. Lens movement with changes in body position is also a characteristic finding of this disease.
It is thought that around the 5th to 6th month of gestation, nutritional deficiency due to defects in the tunica vasculosa lentis causes arrest of secondary lens fiber development 2). The zonular fibers also become underdeveloped, and the lens does not transform into the normal biconvex shape but remains spherical. The lens primordium is originally spherical during the embryonic period, and even in normal infants, a nearly spherical shape may persist shortly after birth.
Inheritance pattern and causative genes: The inheritance pattern is mainly autosomal recessive, but autosomal dominant cases have also been reported. Known causative genes include LTBP2 (latent TGF-β binding protein-2) and ADAMTS17. The LTBP family has structural homology with fibrillin and is expressed in the trabecular meshwork, ciliary processes, and lens capsule. ADAMTS17 belongs to the same metalloprotease family as ADAMTS10, the major gene for Weill-Marchesani syndrome.
Lenticonus is a congenital anomaly in which a cone-shaped protrusion occurs on the anterior or posterior surface of the lens. It results from developmental abnormalities of the lens capsule and lens epithelium, and the protrusion forms at sites where the structural strength of the capsule is locally reduced.
Posterior lenticonus is more common. There are sporadic (unilateral) and familial (bilateral) forms.
Classification and associated diseases:
Anterior lenticonus: Cone-shaped protrusion of the anterior lens surface. Often associated with Alport syndrome (type IV collagen-related gene abnormalities). Structural abnormalities of type IV collagen, which constitutes the anterior lens capsule, are involved in the pathogenesis.
Posterior lenticonus: Protrusion of the posterior lens surface. More common. Associated with Lowe syndrome, Down syndrome, and persistent fetal vasculature (PFV).
Associated diseases: Both microspherophakia and lenticonus may occur as isolated defects or in association with systemic diseases.
Systemic diseases
Weill-Marchesani syndrome: The most common microspherophakia-related disease, with brachydactyly, short stature, and brachycephaly. Autosomal recessive (partially dominant) inheritance.
Alport syndrome: A triad of nephritis, hearing loss, and ocular abnormalities caused by mutations in type IV collagen genes (e.g., COL4A5). A representative disease associated with anterior lenticonus.
Marfan syndrome: A connective tissue disorder caused by FBN1 gene mutations. Lens shape abnormalities may include microspherophakia.
Homocystinuria: Methionine metabolism disorder. Associated with intellectual disability, thrombosis, and downward lens dislocation.
Lowe syndrome: X-linked recessive disorder affecting the eyes, brain, and kidneys. Complicated by posterior lenticonus, cataract, and glaucoma.
Local disease / Sporadic
Sporadic (familial) spherophakia: No systemic abnormalities. Inheritance is often autosomal recessive.
Sporadic (unilateral) posterior lenticonus: The most common form of lenticonus. Occurs unrelated to systemic disease.
Down syndrome: Associated with posterior lenticonus.
Persistent fetal vasculature (PFV): Persistent hyperplastic primary vitreous. Some cases are associated with posterior lenticonus.
Adult Refsum disease: A type of peroxisomal disorder. Cases associated with spherophakia have been reported5).
QCan vision be corrected with contact lenses or glasses?
A
In spherophakia, refractive correction with glasses or contact lenses is possible for high lenticular myopia, and mild cases are candidates for observation. However, if zonular laxity progresses causing lens displacement or glaucoma attack, surgery is necessary. In lenticonus, irregular astigmatism often makes correction with ordinary glasses insufficient; hard contact lenses may be effective, but if severe morphological abnormalities or polar cataracts are present, surgery is indicated.
Unilateral poor vision: Spontaneous posterior conical lens is often unilateral and may be noticed as decreased vision in one eye since childhood. High risk of amblyopia.
The triad of spherical lens is angle-closure glaucoma, shallow anterior chamber, and high lenticular myopia.
Main findings on slit-lamp microscopy are as follows:
Full circumference visibility of the lens equator: Observable under full mydriasis. The lens moves with postural changes.
Shallow anterior chamber: Due to forward displacement of the spherical lens.
Phacodonesis: The lens shakes with eye movements due to zonular laxity.
Iridodonesis: Iris tremor associated with lens instability.
Lens displacement/subluxation: Seen in advanced cases. The smaller the lens equatorial diameter (less than 6.5 mm), the higher the severity of complications 4).
Posterior scleral staphyloma/myopic crescent: Fundus findings in high myopia.
Ultrasound biomicroscopy (UBM) is useful for diagnosing spherical lens, providing two-dimensional cross-sectional images of the anterior segment to assess the morphology of the angle, iris, ciliary body, zonules, and lens. It is particularly useful in cases with insufficient mydriasis.
Slit-lamp microscopy: A conical protrusion of the anterior or posterior lens surface can be observed. Posterior lenticonus is seen as a localized bulge of the posterior capsule on the axis.
Retroillumination: An oil droplet reflex is a characteristic finding, where the conical area appears as a dark spherical shadow.
Retinoscopy: Irregular reflex images corresponding to the conical area are obtained.
Association with polar cataract: In posterior lenticonus, polar cataract with opacity at the posterior pole is frequently associated.
QWhy does glaucoma develop at a high rate?
A
Multiple mechanisms are involved. Acute pupillary block due to anterior movement of the spherophakia, formation of peripheral anterior synechiae due to unresolved pupillary block, chronic narrowing (crowding) of the anterior chamber angle by the spherophakia, and developmental abnormalities of the anterior chamber angle act in combination 1). In spherophakia, glaucoma is associated in 44–51% of cases, and 20–30% of these result in blindness due to glaucomatous optic neuropathy1).
Pathologically, the zonular fibers are abnormally long and somewhat underdeveloped. Abnormal development and arrangement of secondary lens fibers are observed, and changes in lens shape affect the lens fibers, leading to hyaloid degeneration.
The following mechanisms are considered 2):
Arrested development or abnormal attachment of secondary lens fibers due to nutritional deficiency from a defect in the tunica vasculosa lentis during the embryonic period.
Lack of tension in the zonular fibers and arrested lens development cause the lens to remain spherical instead of gradually changing into a normal biconvex lens shape.
Genetic predisposition (LTBP2, ADAMTS17, FBN1 gene mutations) is often present. In cases with secondary glaucoma, management according to glaucoma treatment guidelines is necessary 6).
Due to developmental abnormalities of the lens capsule and lens epithelium, the structural strength of the capsule is locally reduced, causing a conical protrusion.
Anterior lenticonus: Involves abnormalities of type IV collagen (e.g., COL4A5) implicated in Alport syndrome. The mechanism is the same as that of renal basement membrane abnormalities; structural abnormalities of type IV collagen in the anterior lens capsule cause localized weakening of the anterior capsule.
Posterior lenticonus: Caused by developmental failure of the posterior lens capsule. The posterior capsule is inherently thinner than the anterior capsule (approximately 4 μm vs. 14 μm), making it more susceptible to developmental abnormalities. In cases associated with persistent fetal vasculature (PFV), the persistent hyaloid vessels may exert mechanical traction on the posterior capsule.
Local changes in refractive power at the conical area cause irregular astigmatism.
Slit-lamp microscopy: Evaluate the spherical shape of the lens, visibility of the equator, lens tremors, and anterior chamber depth under mydriasis.
Ultrasound biomicroscopy (UBM): Evaluate the anterior chamber angle, ciliary body, zonules, and lens morphology. Particularly useful in difficult cases such as small or fixed pupils.
Examination in supine and sitting positions: Confirm lens movement with changes in body position 1). Cases where the lens further subluxates anteriorly in the supine position are indications for pars plana lensectomy.
Systemic evaluation: Assessment of cardiovascular, skeletal, and metabolic systems. If homocystinuria is suspected, measure serum homocysteine levels and perform urine screening tests.
Slit-lamp microscopy: Confirm conical protrusion of the anterior or posterior lens surface. In posterior lenticonus, it is observed as a localized protrusion of the posterior capsule on the axis.
Retroillumination: Check for the presence of an oil droplet reflex. This is the most characteristic finding and is also useful for detecting mild cases.
Retinoscopy: Evaluate the degree of irregular astigmatism based on irregular reflex images corresponding to the cone area.
Lens subluxation due to Marfan syndrome: May present with spherophakia. Differentiate with FBN1 genetic testing. Lens dislocation is often superotemporal.
Weill-Marchesani syndrome: Most frequently associated systemic disease with spherophakia, accompanied by brachydactyly, short stature, and brachycephaly.
Homocystinuria: Lens dislocation is often downward or into the anterior chamber. Attention to the risk of thrombosis is necessary.
Posterior polar cataract: Opacification of the posterior capsule may resemble posterior lenticonus; morphological evaluation is important.
QHow is lenticonus detected?
A
The most characteristic finding is an oil droplet reflex on transillumination. When the lens is illuminated with retroillumination using a slit lamp, the conical protrusion is observed as a dark spherical shadow. In posterior lenticonus, unilateral visual impairment from childhood is often noticed, and it may be discovered during the workup for amblyopia. In anterior lenticonus, it may be found during ophthalmic screening for Alport syndrome.
Management of spherophakia is performed stepwise depending on the presence and severity of complications.
Medical treatment:
Cycloplegics (mydriatics): Increase tension of the zonules, pulling the lens posteriorly and relieving pupillary block. This is the first-line treatment.
Miotics are contraindicated: Contraction of the ciliary muscle further relaxes the zonules, causing anterior movement of the lens and risk of inducing pupillary blockglaucoma.
Intraocular pressure-lowering drugs: Used for glaucoma management, but often not curative. Management of secondary glaucoma follows the glaucoma treatment guidelines 6).
During acute attack: Intravenous mannitol, pharmacological mydriasis, and supine positioning may be effective 1).
Laser treatment:
Nd:YAG laser iridotomy can be safely performed as the initial procedure to relieve pupillary block. However, its effect on glaucoma is often limited, and due to multiple mechanisms, intraocular pressure control may be insufficient with laser and medication alone 1).
Surgical treatment: From the perspective of glaucoma management, a stepwise protocol is used.
Corneal-lens contact (risk of corneal endothelial damage)
Unilateral high myopia difficult to correct
Pupillary block (laser iridotomy ineffective or insufficient)
Refractory secondary glaucoma
Progressive lens subluxation
Lens opacity (cataract) with decreased visual acuity
After lens extraction, it is important to maintain the compartment between the anterior and posterior segments by preserving the posterior capsule, thereby reducing the risk of vitreous prolapse, cystoid macular edema, and retinal detachment1).
Selection of intraocular lens fixation method: When support from the posterior capsule, zonules, or iris is insufficient, the following options are available1).
Iris-fixated intraocular lens: Causes less endothelial cell damage than anterior chamber intraocular lenses.
Scleral-fixated intraocular lens: Selected when iris tissue is insufficient. Uses 10-0 Prolene or Gore-Tex sutures.
Perform refractive correction with glasses or hard contact lenses from an early stage.
Actively implement amblyopia training (e.g., occlusion therapy).
Visual prognosis is greatly influenced by age at detection and timing of amblyopia treatment initiation.
Surgical indications:
When conservative correction is difficult due to severe keratoconus
When complicated by polar cataract (indication for cataract surgery)
When visual impairment progresses and amblyopia treatment is ineffective
Intraoperative precautions: In posterior keratoconus, the posterior capsule is thinned corresponding to the conical area, posing a high risk of posterior capsule rupture during surgery7).
During phacoemulsification, operate carefully with low perfusion and low aspiration settings.
A backup plan for posterior capsule rupture is essential.
Adjust the capsulorhexis size appropriately, and handle the posterior capsule with particular care.
QWill glaucoma be cured if the lens is removed?
A
In secondary glaucoma associated with spherophakia, intraocular pressure can be controlled without medication in about half of cases after lens extraction. If there is advanced peripheral anterior synechiae or angle abnormalities, extraction alone is insufficient, and additional medical or surgical intervention is needed1). Continuous management according to glaucoma guidelines is important6).
During the embryonic period, the lens is physiologically spherical. Normally, with growth, it changes to a biconvex lens shape due to appropriate traction from the ciliary body and zonules. In spherophakia, it is presumed that this shape change does not occur and the lens remains fixed in a spherical shape1). The posterior zonular fibers do not attach to the ciliary processes, and abnormally long fibers are in a relaxed state.
Mechanism of glaucoma development:
Multiple mechanisms are involved in a complex manner1)2):
Acute pupillary block: Anterior movement of the spherophakic lens, or anterior subluxation of the lens due to zonular relaxation/elongation, causes contact between the iris and lens.
Chronic pupillary block: Crowding of the anterior chamber angle by the spherophakic lens.
Formation of peripheral anterior synechiae: Unresolved pupillary block leads to irreversible damage to the trabecular meshwork.
Angle dysgenesis: Structural maldevelopment of the anterior chamber angle is a predisposing factor.
In the case reported by Bari et al. (2022), the right eye (equatorial diameter 6.01 mm) was smaller than the left eye (6.61 mm) and presented with more severe clinical findings (corneal endothelial damage, glaucomatous visual field defects). It was suggested that the smaller the equatorial diameter of the lens, the more prone it is to anterior subluxation, leading to more severe complications4).
Histopathology: Zonular fibers are abnormally long and somewhat underdeveloped, and abnormal development and distribution of secondary lens fibers are observed. Subsequently, changes in lens shape affect the lens fibers, resulting in hyaline degeneration.
Due to developmental abnormalities of the lens capsule and lens epithelium, the structural strength of the capsule is locally reduced, causing a conical protrusion.
Anterior lenticonus: Type IV collagen abnormality shares the same mechanism as renal basement membrane abnormality in Alport syndrome; structural abnormality of type IV collagen composing the anterior lens capsule leads to localized weakening of the anterior capsule.
Posterior lenticonus: Developmental failure of the posterior lens capsule. The posterior capsule is inherently thinner than the anterior capsule (approximately 4 μm vs. 14 μm), making it more susceptible to developmental abnormalities. The thinned area of the posterior capsule protrudes conically, and at that site, abnormal development of lens fibers (posterior polar cataract) occurs7).
Local changes in refractive power at the conical area are the main cause of irregular astigmatism.
7. Latest Research and Future Perspectives (Investigational Reports)
Sutureless, glue-less, flap-less intrascleral intraocular lens fixation for pediatric lens dislocation has been evaluated. With a mean follow-up of 1 year, 90% of eyes achieved uncorrected visual acuity of 20/60 or better and spherical equivalent within 1 diopter 1). Although reduced postoperative complication risk and improved visual prognosis were demonstrated, long-term outcome data are still limited.
Posterior Capsule Management in Posterior Lenticonus Surgery
In posterior lenticonus, rupture of the thinned posterior capsule is a major intraoperative risk. Hayashi (2001) reported on the relationship between posterior polar cataract and posterior lenticonus, showing that posterior polar opacities corresponding to the thinned area of the posterior capsule occur as a complication of posterior lenticonus7). Phacoemulsification with low perfusion and low aspiration settings combined with anterior vitrectomy in case of posterior capsule rupture is considered effective, but large-scale prospective studies are scarce.
Liu et al. (2026) reported the first case of spherophakia in an adult patient with Refsum disease (peroxisomal disorder) 5). The etiological link between Refsum disease and microspherophakia is unknown, and whether it is an incidental association or a new syndrome overlap remains to be elucidated.
Comparative Studies of Intraocular Lens Fixation Methods
In a comparative study by Yang et al., there was no significant difference in intraocular pressure reduction and visual improvement at 3-year follow-up between the limbal lensectomy + capsule tension ring + intraocular lens group and the pars plana lensectomy + scleral-fixated intraocular lens group 1). Large-scale randomized controlled trials comparing long-term outcomes and complication rates are needed.
Venkataraman P, Haripriya A, Mohan N, Rajendran A. A systematic approach to the management of microspherophakia. Indian J Ophthalmol. 2022;70:2262-71.
Khan TA, Khan AA, Khan A, et al. Bilateral anteriorly displaced microspherophakia in a female child with Marfanoid habitus. Cureus. 2023;15(5):e38371.
Shah A, Kaliaperumal S, Stephen M, Ramachandran K. Microspherophakia with an atypical temporal iris coloboma in a young female. BMJ Case Rep. 2025;18:e264543.
Bari A, Asif MI, Anjum S, Sinha R. Complicated microspherophakia in a paediatric patient. BMJ Case Rep. 2022;15:e249209.
Liu C, Galindez S, Laurent E, Hinkle D. A unique case of microspherophakia in adult Refsum disease. Am J Ophthalmol Case Rep. 2026;41:102495.
日本緑内障学会. 緑内障診療ガイドライン（第5版）. 日眼会誌. 2022;126:85-177.
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