Dislocation of the lens: symptoms, diagnosis, and treatment

Lens dislocation and subluxation are displacements of the natural lens from its normal position due to weakening or rupture of the zonular ligaments. Subluxation refers to partial displacement while maintaining connection with the capsular bag, while dislocation refers to complete displacement of the lens into the anterior chamber or vitreous body. The condition may be congenital or acquired, and may be asymptomatic or lead to a marked decrease in visual acuity, diplopia, impaired accommodation, and significant complications such as acute pupillary block and increased intraocular pressure. [1]

The most common cause in adults is trauma to the eyeball or head. However, with minimal or no trauma, systemic connective tissue disorders, metabolic diseases, and congenital ligamentous anomalies should be considered. Important associations include Marfan syndrome, homocystinuria, Weil-Marchesani syndrome, and pseudoexfoliation syndrome. [2]

The clinical significance stems not only from the loss of clear optics but also from the risks: acute pupillary block with a sharp increase in intraocular pressure, corneal edema from contact of the lens with the endothelium, inflammation, and retinal detachment. Urgent treatment is often required, including medical removal of the block and planned or urgent surgery to remove the lens and select a method for fixing the artificial lens. [3]

Modern diagnostics rely on slit lamp examination, gonioscopy, tonometry, extensive fundus examination, and imaging techniques such as anterior segment optical coherence tomography, ultrasound biomicroscopy, and, in cases of trauma, orbital computed tomography. Treatment is individualized based on age, underlying condition, degree of displacement, and the presence of complications. [4]

ICD-10 and ICD-11 codes

In the International Classification of Diseases, Tenth Revision, displacement of the natural lens is classified under the heading H27.1. For clarification, the following subheadings are often used: H27.11 "subluxation of the lens," H27.12 "anterior dislocation of the lens," H27.13 "posterior dislocation of the lens." For displacement of the artificial lens, other codes are used that are not included in this heading. [5]

In the International Classification of Diseases, Eleventh Revision, lens displacement is classified under the "Certain Disorders of the Lens" section with the specific entry "Dislocation of lens," code 9B11.1. For congenital anomalies of the capsular-zoonoid apparatus and familial ectopia lentis, the structural anomalies section "LA12," including the entry "LA12.Y," is used. For complications such as secondary angle-closure glaucoma with pupillary block, a combination of codes is used with mandatory indication of the causative condition. [6]

Table 1. Codes according to ICD-10 and ICD-11

Classifier	Code	Name
ICD-10	H27.1	Dislocation of the lens
ICD-10	H27.11	Subluxation of the lens
ICD-10	H27.12	Anterior lens dislocation
ICD-10	H27.13	Posterior lens dislocation
ICD-11	9B11.1	Displacement of the lens
ICD-11	LA12.Y	Other structural congenital anomalies of the lens or zonules
ICD-11 (related)	9C61.30 + 9B11.1	Secondary angle-closure glaucoma with pupillary block due to lens displacement

Epidemiology

A universal estimate of the prevalence of lens displacement in the general population is difficult due to the heterogeneity of causes and diagnostic differences. However, trauma remains the most common cause, especially in unilateral cases in adults. In retrospective series, traumatic displacement was often associated with other anterior and posterior segment injuries. [7]

In Marfan syndrome, lens displacement develops in a significant proportion of patients over the course of their lives. The incidence reported is approximately 65% in specialized foundation data and up to 80% in reviews, with the typical direction of displacement being upward and toward the temple. This reflects the congenital weakness of the fibrillin-1 microfibrils in the zonular zone. [8]

In homocystinuria, the displacement is usually bilateral and directed downward and toward the nose. The incidence increases with age: approximately 70% in children under 7 years of age and up to 90% by adulthood. This is due to the toxic effect of elevated homocysteine on the structure of the ligaments. [9]

Rare congenital syndromes, such as Weil-Marchesani syndrome, are often associated with microspherophakia and a high risk of angle-closure glaucoma. In reviews, the proportions of ophthalmologic manifestations reach high values, including microspherophakia and lens displacement. [10]

Table 2. Epidemiological landmarks

Situation	Frequency or proportion	Notes
Traumatic displacement	There is no data on the exact prevalence, but the cause is most common	Often combined damage, often acute pupillary block
Marfan syndrome	65-80% during life	Typically shifted upward and towards the temple
Homocystinuria	70% in children under 7 years old, 90-95% in adults	Downward and nasal displacement, bilateral
Weil-Marchesani syndrome	High proportion of microspherophakia and displacement	Frequent episodes of angle-closure glaucoma

Reasons

The leading cause in adults is blunt or penetrating trauma to the eyeball, a blow from a ball, a fall, or a car accident. The force of the impact causes a rupture or diffuse stretching of the ligaments, leading to lens displacement. If a concomitant rupture of the eyeball is suspected, orbital CT scanning without compressing the eyeball is preferred. [11]

Hereditary and metabolic factors include Marfan syndrome with mutations in the fibrillin-1 gene, homocystinuria with cystathionine beta synthase deficiency, and Weil-Marchesani syndrome with a genetic spectrum that includes genes of the ADAMTS family. These conditions initially weaken the ligamentous apparatus. [12]

Pseudoexfoliation syndrome is an age-associated disorder characterized by the deposition of fibrillar material on the zonules, lens capsule, and iris. It increases the risk of spontaneous lens instability, subluxation, and surgical complications, although it is most often associated with late dislocation of the artificial lens. [13]

Less frequently, displacement is associated with inflammatory processes and neoplasms of the anterior segment, congenital anomalies, hypermature cataracts, as well as systemic connective tissue syndromes, including Ehlers-Danlos syndrome. [14]

Risk factors

Key risk factors include: 1) previous eye or head trauma, 2) systemic connective tissue diseases, 3) metabolic disorders with elevated homocysteine, 4) pseudoexfoliation syndrome, 5) congenital anomalies of the zonules and lens capsule. The combination of several factors significantly increases the likelihood of displacement. [15]

Those at risk include children and young adults with hereditary syndromes, especially in familial cases, as well as elderly patients with significant deposits of pseudoexfoliative material. Screening for systemic signs helps identify latent forms. [16]

Previous intraocular surgery and severe myopia may be accompanied by latent zonulopathy, which facilitates lens displacement with minor impacts. The presence of microspherophakia creates a predisposition to pupillary block even without trauma. [17]

Vascular and systemic features in certain syndromes, including cardiac and vascular changes in Marfan syndrome and syndromes with microspherophakia, require interdisciplinary monitoring. This influences the timing and extent of surgery. [18]

Table 3. Risk factors for lens displacement

Factor	Mechanism
Injury	Rupture or diffuse stretching of the zonular ligaments
Marfan syndrome	Fibrillin-1 defect, microfibril weakness
Homocystinuria	The toxic effect of homocysteine on ligaments
Pseudoexfoliation syndrome	Deposits on links, structural weakness
Microspherophakia	Anatomical predisposition to pupillary displacement and block

Pathogenesis

The underlying mechanism is a loss of tension or rupture of the zonular ligaments that hold the capsular bag containing the lens. Partial damage results in decentration and lens vibration (phacodonesis), while complete damage results in free movement of the lens into the anterior chamber or vitreous body. This alters the optics of the eye and the hydrodynamics of the aqueous humor. [19]

In Marfan syndrome, disruption of fibrillin-1 microfibrils leads to systemic weakness of connective tissue, including the lens ligament apparatus. Structural weakness progresses with age, increasing the likelihood of displacement. A typical displacement vector is upward and toward the temple. [20]

In homocystinuria, chronically elevated homocysteine disrupts the cross-linking of extracellular matrix proteins and degrades the ligaments. As a result, the displacement is often bilateral, directed downward and toward the nose, and progresses with age. [21]

Pseudoexfoliative material is deposited on the ligaments and capsule, causing their thinning and loosening. This increases the risk of spontaneous displacement and complicates any manipulation of the anterior segment due to latent instability. [22]

Symptoms

Patients complain of decreased visual acuity, distortions, monocular diplopia, image "swaying," and glare. Episodes of sudden blurring are possible when changing head position due to a shift in the optical axis. In children, amblyopia develops rapidly if ametropia is not corrected. [23]

Objectively, iridodonesis and phacodonesis, decentration of the pupillary reflex, and changes in the depth of the anterior chamber are noted. With anterior dislocation, contact of the lens with the corneal endothelium and an inflammatory reaction are possible. With posterior dislocation, a floating lens in the vitreous body is observed. [24]

Acute increase in intraocular pressure occurs with pupillary block, especially in the setting of microspherophakia or anterior displacement. Accompanying symptoms include pain, redness, nausea, halos, and severe discomfort. Emergency care is required. [25]

Trauma can cause concomitant iris ruptures, sphincter ruptures, traumatic cataracts, retinal tears, and hemorrhages. This affects the prognosis and extent of intervention. [26]

Table 4. Clinical signs of lens displacement

Sign	What are we looking for?
Phacodonesis, iridodonesis	Vibration of the lens and iris when the eye moves
Decentration	Misalignment of optical axes, displacement of light reflex
Changing the depth of the anterior chamber	Asymmetry by quadrants, local shallow place
Contact with the cornea	Corneal edema, pain syndrome
Signs of pupillary block	Pain, fog, rainbow circles, increased pressure

Classification, forms and stages

Based on the degree of displacement, subluxation (partial), dislocation into the anterior chamber, and dislocation into the vitreous body are distinguished. Based on etiology, there are traumatic, hereditary, metabolic, associated with pseudoexfoliation syndrome, and congenital anomalies. This classification determines the diagnostic and treatment algorithm. [27]

In terms of the direction of displacement, the typical vector is upward and toward the temple in Marfan syndrome and downward and toward the nose in homocystinuria, but any variation is possible. The direction reflects damage to specific sectors of the zonular ligaments. [28]

According to the course, acute events (for example, acute anterior dislocation with pupillary block) and chronic progressive decentration are distinguished. The chronic course may be asymptomatic for a long time, but carries the risk of sudden decompensation. [29]

Microspherophakia is considered separately as a form of congenital lens anomaly with an increased risk of episodes of block and the need for surgical removal of the lens to control intraocular pressure. [30]

Complications and consequences

Acute pupillary block leads to a sharp increase in intraocular pressure, pain, and corneal swelling, which, if left untreated, can lead to permanent vision loss. In some patients, conservative measures are insufficient, requiring lens removal. [31]

Contact of the lens with the endothelium causes corneal edema, bullous keratopathy, and the need for keratoplasty in persistent cases. With posterior dislocation, there is a risk of inflammation and secondary retinal traction pathology. [32]

In children, untreated ametropia and unstable optics lead to amblyopia and strabismus. With timely rehabilitation, the incidence of amblyopia decreases over time, especially with structured observation. [33]

In pseudoexfoliation syndrome, surgical complications and late displacement of the artificial lens are more common, which dictates caution and careful planning of surgery and monitoring. [34]

When to see a doctor

Immediately - if you experience sudden eye pain, blurred vision, halos, nausea, and vomiting: these are signs of acute pupillary block and a sharp increase in intraocular pressure. Urgency is necessary due to the risk of irreversible damage to the visual structures. [35]

In the near future - with sudden double vision, a "shaking picture" effect, the appearance of a dark object "floating" in the field of vision, or a noticeable decentration of the pupillary reflex. This may indicate a subluxation or posterior dislocation. [36]

Planned - in familial cases of connective tissue syndromes, high myopia, pseudoexfoliation syndrome, as well as before any intraocular surgery to assess the strength of the ligamentous apparatus. [37]

Children with congenital forms require observation by a pediatric ophthalmologist and orthoptologist to prevent amblyopia, even in the absence of pronounced complaints. [38]

Diagnostics

The initial evaluation includes a history (trauma, systemic symptoms), visual acuity testing, tonometry, and a slit-lamp examination with maximum pupil dilation, unless contraindicated. Signs of phacodonesis, ligament rupture, direction of displacement, and corneal contact are sought. [39]

Gonioscopy is then performed to assess the anterior chamber angle and signs of angle-closure. If pupillary block and high intraocular pressure are suspected, emergency drug treatment is initiated pending further testing. [40]

Anterior segment imaging includes anterior segment optical coherence tomography and ultrasound biomicroscopy, which allow quantitative assessment of tilt, decentration, and ligament integrity. These techniques are particularly useful in dense cataracts or severe opacities. [41]

In cases of trauma and suspected rupture of the eyeball, orbital CT scanning is preferred to detect the "floating lens sign" and rule out dangerous conditions. Ultrasound scanning is used to detect posterior dislocation and evaluate the vitreous body. Genetic testing and systemic screening are also considered if hereditary syndromes are suspected. [42]

Table 5. Diagnostic algorithm

Step	Target	Tool
Slit lamp examination	Confirmation of displacement, assessment of corneal contact	Biomicroscopy
Estimation of angle and pressure	Identifying pupillary block and glaucoma risk	Gonioscopy, tonometry
Anterior segment visualization	Quantitative assessment of decentration and connections	Optical coherence tomography of the anterior segment, ultrasound biomicroscopy
Imaging in trauma	Safe confirmation of dislocation, associated injuries	Computed tomography of the orbits
Systematic assessment	Search for the causal condition	Genetic testing, biochemistry (homocysteine), cardiac screening

Differential diagnosis

It is necessary to differentiate lens displacement from severe cataracts with false decentration of the light reflex, from artifacts associated with a small pupil, and from the consequences of previous surgeries. In doubtful cases, anterior segment optical coherence tomography and ultrasound biomicroscopy are helpful. [43]

Microspherophakia mimics subluxation due to an abnormally convex lens with a reduced equator and a tendency toward anterior displacement. It often underlies recurrent episodes of angle-closure glaucoma. [44]

Traumatic aphakia following capsule rupture and fragment extraction, as well as displacement of the artificial lens, require different approaches to coding and treatment and should not be confused with conditions of the natural lens. [45]

Concomitant conditions such as anterior segment inflammation and secondary glaucoma are considered complications rather than independent underlying causes of misalignment.[46]

Table 6. What distinguishes the main states

State	Distinguishing features	Confirmation
Subluxation of the lens	Phacodonesis, sector decentration	Biomicroscopy, optical coherence tomography
Anterior dislocation	The lens is in the anterior chamber, corneal edema	Biomicroscopy, tonometry
Posterior dislocation	Crystalline lens in the vitreous body	Ultrasound, in case of trauma - computed tomography
Microspherophakia	Small diameter, high curvature, tendency to block	Biomicroscopy, ultrasound biomicroscopy

Treatment

The initial goal for acute anterior displacement is to relieve pupillary block and reduce intraocular pressure. Ophthalmic hypotensive agents, osmotic agents for high pressure, and anti-inflammatory therapy are used. Laser peripheral iridotomy is used to correct the block, but if the lens is displaced, this may not be sufficient, requiring surgical removal of the lens. [47]

In cases of uncomplicated posterior dislocation and acceptable vision, observational therapy with regular tonometry and retinal examination is possible. Indications for surgery are determined by inflammation, instability, repeated visual fluctuations, increased pressure, or the impossibility of optical correction. [48]

In cases of severe subluxation with an intact capsular bag, capsule stabilization is performed using tension rings and their modifications with scleral fixation. This tactic allows for phacoemulsification and implantation of an artificial lens into the capsular bag while maintaining its physiological position. [49]

If capsular support is insufficient, the artificial lens is fixed to the iris using special "claw" supports placed behind the iris. This approach ensures rehabilitation even with low endothelial cell density, but control of inflammation and intraocular pressure in the postoperative period is important. [50]

An alternative is scleral fixation of a posterior chamber artificial lens. Options include suture fixation with non-absorbable materials and sutureless techniques with haptic extraction and flange formation. Modern studies demonstrate comparable visual acuity and complication profiles between classical and sutureless methods, given proper patient selection and surgeon experience. [51]

Expanded polytetrafluoroethylene-based suture fixation options demonstrate good visual outcomes but require careful node coverage under scleral flaps and active monitoring for rare but reported complications, including scleromalacia. The choice of suture material and technique influences long-term stability. [52]

Sutureless techniques using double needles and haptic flanges reduce surgical time and eliminate the risks associated with suture wear. Meta-analyses and comparative studies show comparable or better refractive accuracy and a lower incidence of iris entrapment, but long-term follow-up is needed to draw definitive conclusions. [53]

In children with hereditary forms, the goal of surgery is not only to stabilize the optics but also to prevent amblyopia. Treatment options include intralenticular aspiration through small incisions, lens removal followed by implantation of a suitable artificial lens, or optical rehabilitation with contact lenses and glasses. The strategy depends on the patient's age, degree of displacement, and associated pathology. [54]

In cases of microspherophakia and recurrent elevated intraocular pressure, lensectomy often provides better control than isolated antiglaucoma surgery. Even with laser iridotomy, some patients require lens removal for sustained normalization of hydrodynamics. [55]

Optical rehabilitation after cataract surgery includes contact lenses, glasses, or implantation of an artificial lens with available support. Control of inflammation, prevention of cystoid macular edema, and pressure monitoring are essential. Patients with systemic syndromes are simultaneously monitored by a cardiologist and geneticist. [56]

Table 7. Selection of surgical tactics according to the situation

Situation	Preferred approach
Acute anterior dislocation with pupillary block	Medication to lower blood pressure, laser iridotomy, and cataract removal
Subluxation with intact bursa	Tension ring, modified ring with scleral fixation, implantation in the bag
There is no capsule support	Iris-to-iris or scleral fixation of a posterior chamber artificial lens
Microspherophakia with increased pressure	Removal of the lens as a method of pressure control
Childhood, congenital forms	Organ-preserving approaches, early rehabilitation for the prevention of amblyopia

Table 8. Options for fixing the artificial lens: strengths and weaknesses

Method	Strengths	Restrictions
Fixation in a capsule bag with a tension ring	Physiological position, stability	Requires sufficient capsular support
Fixation on the iris after the iris	No sutures to the sclera, fast rehabilitation effect	Risk of increased pressure and cystoid macular edema, requirements for iris anatomy
Scleral fixation with sutures	Wide applicability, posterior chamber position	Risks of seam rupture and erosion, technical complexity
Seamless scleral fixation with flanges	No seams, comparable results	Dependence on technology and experience, limited long-term data

Prevention

Eye protection during sports and work reduces the risk of traumatic eye injuries. The use of certified protective eyewear is especially important in ball sports and when working with tools. [57]

Patients with Marfan syndrome, homocystinuria, and Weil-Marchesani syndrome require regular ophthalmologic monitoring with assessment of the zonular apparatus, selection of optics, and early detection of signs of decentration. Interdisciplinary monitoring improves long-term prognosis. [58]

In pseudoexfoliation syndrome, careful preoperative evaluation and gentle techniques during anterior segment interventions, as well as patient education about the risks of late instability, are recommended. [59]

Untested pupil dilators should be avoided in individuals with microspherophakia and a tendency to pupillary block, and symptoms of increased pressure and pain should be addressed immediately. [60]

Forecast

The prognosis depends on the cause, the speed of intervention, and the presence of complications. With timely intervention and adequate optical rehabilitation, functional vision may be restored. A delay in acute pupillary block significantly worsens the outcome. [61]

In children, the prognosis improves with early correction of ametropia and prevention of amblyopia. Risk models help identify patients who require more intensive monitoring. [62]

In hereditary syndromes, the risk of recurrence and bilateral progression remains, so long-term monitoring is necessary. In most cases, modern methods of artificial lens fixation provide stable results, but require experience and proper technique selection. [63]

In pseudoexfoliation syndrome, the long-term prognosis is determined not only by optics, but also by control of concomitant glaucoma and the quality of the corneal endothelium. [64]

FAQ

Is it possible to "reposition" the crystalline lens without surgery? In cases of posterior dislocation without complications, observation is sometimes the preferred treatment. In cases of anterior dislocation with pupillary block, attempts at positional repositioning and laser iridotomy can provide a temporary solution, but lens removal is often necessary. [65]

What's the difference between a subluxation and a dislocation? A subluxation is a partial displacement with intact connection to the sac and ligaments, while a dislocation is a complete displacement of the lens into the anterior chamber or vitreous body. This influences the tactics and urgency of treatment. [66]

What direction of displacement is typical for these syndromes? For Marfan syndrome, it is usually upward and toward the temple; for homocystinuria, it is downward and toward the nose, but exceptions are possible. [67]

Is surgery always necessary for a child? The decision is individual. The goal is stable vision and amblyopia prevention. Contact lenses and glasses are used, as well as gentle surgical techniques with subsequent rehabilitation. [68]

How is the method of fixation for an artificial lens chosen? The integrity of the capsule, the condition of the iris, the risks to the cornea, and the surgeon's experience are all considered. Fixation in a bag with tension rings, fixation to the iris behind the iris, and scleral techniques with or without sutures are available. [69]

Is pseudoexfoliation dangerous? Yes, it weakens the ligaments, increasing the risk of displacement and surgical complications, and therefore requires more frequent examinations and careful planning of interventions. [70]