Atopic Cataract

1. What is atopic cataract?

Atopic cataract is a cataract associated with atopic dermatitis (AD) and is the most common cause of cataract in young people. It occurs frequently in cases with severe skin symptoms and is often bilateral. It is also frequently associated with keratoconjunctivitis, keratoconus, and retinal detachment.

Epidemiology

The incidence of cataracts in AD patients is reported to be 0–25% in many studies. It often develops in young individuals (late teens and older) and is the most common cause of juvenile cataracts.

Cataracts in AD patients were reported even before the widespread use of topical steroids, in the 1930s–1940s. Brunsting (1936) found cataracts in about 10% of 101 AD patients (mean age 22 years) at the Mayo Clinic, and Brunsting and Bair et al. (1940–1953) found cataracts in 11.7% of 1,158 AD patients. There was no significant change in incidence before and after the introduction of topical steroids, suggesting that topical steroids are not the main cause.

Risk Factors for Cataract Development

Risk factors for cataract development in AD patients are listed below.

Risk factor	Notes
Severity of facial AD	Higher incidence in severe cases
History of eye rubbing	Chronic physical irritation
Serum LDH level	Indicator of inflammatory activity
Serum eosinophil count	Degree of eosinophilic inflammation
Serum ECP level	Concentration of eosinophil granule protein
Anterior chamber flare value	Degree of blood-aqueous barrier disruption

Q Is atopic cataract caused by topical steroids?

Topical steroids are not considered the main cause. Cataracts in patients with atopic dermatitis were already reported in 1936, before the introduction of topical steroids, and the incidence rate has not changed significantly before and after their introduction. The main causes are chronic physical stimulation from eye rubbing and influx of eosinophil granule proteins into the eye, and the involvement of topical steroids is considered unlikely.

2. Main symptoms and clinical findings

Subjective symptoms

Decreased vision: Occurs relatively early when anterior subcapsular opacity involves the visual axis
Photophobia: Sensitivity to light stimulation
Blurred vision: Overall haziness of the visual field

Disease types and clinical findings

The characteristic lens opacities in atopic cataract are “star-shaped,” “stellate,” or “crack-like linear opacities” under the anterior capsule, resembling traumatic (contusion) cataract. The disease types are broadly classified into two categories.

Plaque (Vogt) type

Opacity location: Only anterior subcapsular opacity

Morphology: Star-shaped opacity along the Y-shaped suture. Caused by degeneration of the superficial cortex and focal multilayering of epithelial cells.

Course: Progresses relatively slowly

Complicated type

Opacity location: Complicated with anterior and posterior subcapsular opacities

Morphology: Opacities in the anterior and posterior subcapsular regions. May form water clefts in the lens cortex

Course: Opacity progresses rapidly. If water clefts develop, it may become an intumescent cataract in a short period

Associated findings

Keratoconjunctivitis (allergic eye diseases such as vernal keratoconjunctivitis)
Keratoconus
Retinal detachment (higher complication rate when cataract is severe)
Zonular weakness/rupture: The zonules may be ruptured due to physical stimulation from eye rubbing. Preoperative confirmation is essential.

Q How does atopic cataract progress?

The plaque (Vogt) type progresses relatively slowly with only anterior subcapsular opacity. In contrast, the complicated type involves both anterior and posterior subcapsular opacity and progresses rapidly. If water clefts develop in the complicated type, it can rapidly lead to intumescent cataract. Since it occurs in young individuals, if left untreated, the impact on visual function can be long-lasting.

3. Causes and Risk Factors

The main cause of atopic cataract associated with AD is thought to be physical stimulation from long-term eye rubbing and tapping due to itching of blepharitis, and the subsequent influx of eosinophil granule proteins into the eye due to disruption of the blood-aqueous barrier.

Physical stimulation: Itching of blepharitis associated with AD → habitual eye tapping and rubbing → chronic trauma to the lens
Inflammatory/immunological mechanisms: Disruption of the blood-aqueous barrier → influx of serum eosinophil granule proteins (e.g., ECP) into the eye → damage to lens epithelial cells → opacification
Genetic background: Single nucleotide polymorphisms (SNPs) in the IFN receptor have been reported as risk factors for cataract development. In NC/Nga mice (a spontaneous AD model), lens epithelial cells undergo apoptosis regardless of AD onset, suggesting a genetic predisposition.
Role of topical steroids: Not a primary cause (see previous section)
It is also known as one of the causative diseases of Zinn zonule weakness⁷⁾

4. Diagnosis and Examination Methods

Diagnostic Requirements

The diagnosis of atopic cataract is based on the combination of the following two points.

Confirmation of atopic dermatitis (dermatological diagnosis)
Confirmation of star-shaped, asteroid, or cracked anterior subcapsular opacity by slit-lamp microscopy

Differential Diagnosis

For differential diagnosis, the combination of opacity location, morphology, and medical history is important.

Differential Diagnosis	Opacity Location	Opacity Morphology	Notes
Atopic cataract	Anterior subcapsular (± posterior subcapsular)	Star-shaped, stellate, or cracked-ice appearance	History of atopic dermatitis, eye rubbing
Steroid cataract	Posterior subcapsular (± nuclear)	Diffuse opacity just beneath the posterior capsule	History of steroid use
Traumatic cataract	Anterior subcapsular	Star-shaped (similar)	Clear history of trauma

Preoperative evaluation (required)

Before surgery for atopic cataract, in addition to standard cataract surgery, the following evaluations are required.

Presence of zonular rupture: Check for asymmetry in anterior chamber depth and lens instability
Peripheral retinal examination: Evaluate for retinal detachment or tears
Ultrasound biomicroscopy (UBM): Useful for detecting ciliary sulcus tears and epithelial detachment⁴⁾
Gonioscopy or Goldmann three-mirror lens: Useful for confirming ciliary sulcus tears associated with atopic dermatitis
B-scan ultrasonography: Performed when cataract is severe and fundus view is poor

Q How to differentiate atopic cataract from steroid cataract?

The opacity location differs. Atopic cataract is characterized by star-shaped, asteroid, or cracked anterior subcapsular opacities, resembling traumatic cataract. Steroid cataract primarily involves posterior subcapsular opacity (with more nuclear and posterior subcapsular opacities). Differentiation is based on a combination of medical history (history of atopic dermatitis or steroid use) and slit-lamp findings.

5. Standard Treatment

Pharmacotherapy (Prevention and Progression Suppression)

Controlling atopic blepharitis reduces eye rubbing behavior, thereby suppressing the onset and progression of cataracts.

Tacrolimus ointment 0.1% (Protopic ointment): Used for severe atopic blepharitis. Apply carefully to avoid contact with the eyelids. Expected to reduce eye rubbing behavior and decrease cataract incidence.
Systemic treatment of atopic dermatitis to control skin symptoms is fundamental for preventing ocular complications.

Cataract Surgery

Phacoemulsification (PEA) + intraocular lens (IOL) implantation is performed. Since many patients are young and the nucleus is soft, ultrasonic fragmentation itself is easy.

Intraoperative precautions:

Confirmation of zonular weakness or rupture is essential (reconfirm intraoperatively along with preoperative evaluation)
Peripheral retinal examination (for tears or detachment)
If the cataract is white, ensuring visibility of the anterior capsule is necessary

Surgical technique using anterior capsule staining

In white cataract (complete lens opacification), CCC (continuous curvilinear capsulorhexis) is often difficult. The anterior capsule is visualized using an anterior capsule staining solution.

The characteristics of major anterior capsule staining solutions are shown below.

Staining solution	Concentration	Staining property	Remarks
ICG (Indocyanine Green)	0.125%	Good	Used for anterior capsule staining¹⁾
TB (Trypan Blue)	0.1% (1 mg/mL)	Very good	Caution for corneal endothelial cell toxicity with high concentration and prolonged exposure⁵⁾⁶⁾
BBG (Brilliant Blue G)	0.025%	Good	Has been used in retinal surgery; application to anterior capsule staining is at the discretion of the facility

Atopic cataract with anterior capsule fibrosis: After staining with TB, puncture with a 27-gauge needle → CCC with forceps → Incise the fibrotic area with scissors¹⁾
Anterior chamber formation with high molecular weight high concentration OVD (Healon V®) is recommended¹⁾

Management of Zonular Weakness Cases

Atopic cataract is one of the causes of zonular weakness⁷⁾⁸⁾. If weakness or rupture is confirmed, consider the following measures.

Consider using a capsular tension ring (CTR)²⁾
If lens instability or poor capsular support is present, prepare preoperatively for CTR, capsule hooks, or changes in IOL fixation method.

Management of IOL Decentration or Dislocation

In patients with a habit of hitting the eye, re-decentration or re-dislocation may occur after IOL fixation, so it is important to suppress eye-pounding behavior and conduct long-term follow-up.

IOL suturing: Methods using 8-0 or 9-0 polypropylene sutures have been reported³⁾
The fixation method (suturing, intrascleral fixation, etc.) is selected individually based on the persistence of eye rubbing, capsular support, corneal endothelium, and surgeon experience

Postoperative Management

Continued control of atopic blepharitis (continued use of tacrolimus ointment 0.1%)
Guidance to suppress eye scratching and rubbing behavior (essential for preventing IOL displacement)
Regular retinal examination (possibility of postoperative retinal detachment)

Q What are the particular points to note in surgery for atopic cataract?

The main differences from standard cataract surgery are the fragility/rupture of the Zinn zonules and the complication of retinal detachment. Preoperatively, check for these conditions and prepare for CTR or IOL suturing. If the cataract is white, use anterior capsule staining (ICG, TB, BBG) to ensure visibility of the CCC anterior capsule. Postoperatively, suppressing eye-rubbing behavior is essential for maintaining IOL stability.

6. Pathophysiology and Detailed Pathogenesis

The pathogenesis of atopic cataract is not fully understood, but it is thought to involve a combination of physical stimulation, inflammatory immunological mechanisms, and genetic predisposition.

Physical Stimulation Theory

Itching sensation of blepharitis associated with AD → long-term eye scratching and tapping behavior
Chronic trauma to the lens due to physical stimulation
The opacity pattern resembles traumatic (contusion) cataract, supporting this theory

Inflammatory and immunological mechanisms

Disruption of the blood-aqueous barrier → influx of serum eosinophil granule proteins (e.g., ECP) into the eye
Elevated anterior chamber flare (protein concentration) is a risk factor
Eosinophil granule proteins damage lens epithelial cells → opacity formation

Genetic Predisposition

Single nucleotide polymorphisms (SNPs) in the IFN receptor have been reported as risk factors for cataract development.
In NC/Nga mice (spontaneous AD model), lens epithelial cells undergo apoptosis regardless of AD onset, suggesting a genetic predisposition.
It may develop through a synergistic effect of genetic background and eye-rubbing behavior.

Pathology of the Zonules of Zinn

Chronic mechanical stress from eye rubbing causes rupture of zonular fibers⁷⁾
The zonule of Zinn is divided into anterior, equatorial, and posterior parts. The anterior zonular fibers branch in a fan shape and attach to the anterior capsule surface at the equator ⁸⁾
When severe, it causes lens dislocation (subluxation or luxation)

Morphological features of disease types

Plaque type: Degeneration of the superficial cortex and focal multilayering of epithelial cells → stellate opacity
Complicated type: Formation of water clefts → rapid progression of cortical opacity → intumescent cataract

7. Latest research and future perspectives

The introduction of non-steroidal immunosuppressive topical agents such as tacrolimus ointment has improved control of atopic blepharitis and is expected to reduce the incidence of cataracts.
Research is currently underway on the impact of the transformation of AD treatment with biologics such as dupilumab on ocular complication management (especially cataracts and vernal keratoconjunctivitis).
Elucidation of the molecular mechanism of lens epithelial cell apoptosis in the NC/Nga mouse model may contribute to understanding genetic predisposition.
Advances in IOL materials and fixation methods are expected to improve postoperative outcomes. The development of fixation methods with excellent long-term stability for cases with a habit of hitting is a challenge.

8. References

Horiguchi M, Miyake K, Ohta I. Staining of the lens capsule for circular continuous capsulorrhexis in eyes with white cataract. Arch Ophthalmol. 1998;116(4):535-537. doi:10.1001/archopht.116.4.535. PMID: 9554390.
Gimbel HV, Sun R, Heston JP. Management of zonular dialysis during phacoemulsification with endocapsular ring implantation. J Cataract Refract Surg. 2001;27(3):447-456. PMID: 11255167.
John T, Tighe S, Hashem O, et al. New use of 8-0 polypropylene suture for four-point scleral fixation of secondary intraocular lenses. J Cataract Refract Surg. 2018;44(12):1421-1425. doi:10.1016/j.jcrs.2018.03.046. PMID: 29986239.
Tanaka M, Sunaga S, Ideta H, Fukumoto M, Kishi S, Komatsu H. Ultrasound biomicroscopy in the detection of breaks in detached ciliary epithelium. Am J Ophthalmol. 1999;128(4):466-471. PMID: 10577532.
Melles GR, de Waard PW, Pameyer JH, van Vroonhoven CC. Trypan blue capsule staining to visualize the capsulorhexis in cataract surgery. J Cataract Refract Surg. 1999;25(1):7-9. doi:10.1016/S0886-3350(99)80004-2. PMID: 9932174.
Hofmann C, Thaler S, Spitzer MS, et al. Blue dyes in ophthalmic surgery. Acta Ophthalmol Scand. 2006;84(5):633-638. doi:10.1111/j.1600-0420.2006.00655.x. PMID: 16801512.
Dureau P. Pathophysiology of zonular diseases. Curr Opin Ophthalmol. 2008;19(1):27-30. doi:10.1097/ICU.0b013e3282f1ab1f. PMID: 18090915.
Assia EI, Apple DJ, Morgan RC, Legler UF, Brown SJ. The relationship between the stretching capability of the anterior capsule and zonules. Invest Ophthalmol Vis Sci. 1991;32(10):2835-2839. PMID: 1915446.

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