Ophthalmology – Lattice Degeneration

Basics

Description

Lattice degeneration is a common peripheral retinal degeneration characterized by areas of retinal thinning with abnormal vitreoretinal adhesion along their borders.

It is important because affected areas may develop:

• Atrophic retinal holes
• Retinal tears
• Rhegmatogenous retinal detachment

Despite this association, most people with lattice degeneration never develop a retinal detachment.

Epidemiology

Lattice degeneration is found in approximately 6–10% of the general population.

It is more common in:

• Myopic eyes
• Patients with a family history of retinal detachment
• Certain hereditary vitreoretinal disorders

Lattice degeneration is present in a substantial proportion of eyes that develop retinal detachment, but its presence alone does not mean that detachment will occur.

Risk Factors

Important risk factors include:

• Myopia
• Family history of lattice degeneration or retinal detachment
• Previous retinal tear or detachment in the fellow eye
• Stickler syndrome
• Wagner syndrome
• Other hereditary vitreoretinal disorders

High axial myopia is particularly associated with peripheral retinal degenerative changes.

General Prevention

There is no known method to prevent lattice degeneration from developing.

Management therefore focuses on:

• Identifying high-risk patients
• Recognizing associated retinal tears
• Educating patients about retinal detachment symptoms
• Treating significant retinal breaks when indicated

Pathophysiology

The affected peripheral retina undergoes inner retinal thinning and atrophy.

Overlying the lattice lesion, the vitreous tends to become liquefied.

At the edges of the lesion, however, the vitreous remains more firmly attached to the retina.

This combination creates:

• Thin retina within the lesion
• Liquefied vitreous over the lesion
• Strong vitreoretinal adhesion at its margins

When the posterior vitreous separates, traction at these firmly adherent borders can produce a retinal tear.

Atrophic holes can also develop directly within the thinned retina.

Etiology

The precise cause is unknown.

A genetic predisposition is likely, particularly because lattice degeneration is more common in families with:

• Retinal detachment
• High myopia
• Hereditary vitreoretinal disease

Commonly Associated Conditions

Important associations include:

• Axial myopia
• Atrophic retinal holes
• Peripheral chorioretinal atrophy
• Retinal tears
• Posterior vitreous detachment
• Stickler syndrome
• Wagner syndrome

Diagnosis

History

Most lattice degeneration is discovered incidentally during a dilated retinal examination.

Patients may be completely asymptomatic.

When symptoms occur, they are usually related to an associated posterior vitreous detachment or retinal tear rather than the lattice itself.

Important symptoms include:

• New flashes of light
• New floaters
• Sudden increase in floaters
• A curtain or shadow in the visual field
• Peripheral visual field loss
• Sudden decrease in vision

History should also include:

• Previous retinal tear
• Previous retinal detachment
• Retinal detachment in the fellow eye
• Family history of retinal detachment
• Degree of myopia

Patients who have previously undergone refractive surgery or cataract surgery may no longer appear highly myopic by refraction, so a history of preoperative myopia should specifically be obtained.

Physical Examination

A complete dilated retinal examination is required.

The vitreous should first be examined for evidence of acute posterior vitreous separation or retinal tearing.

Vitreous Pigment

Pigment cells dispersed within the anterior vitreous may suggest the presence of a retinal tear.

This finding is sometimes referred to clinically as Shafer sign or “tobacco dust.”

When present in a symptomatic patient, a careful search for a retinal break is essential.

Posterior Vitreous Detachment

The examiner should determine whether a posterior vitreous detachment is present.

Acute PVD can generate traction at the edges of lattice degeneration and increase the risk of a horseshoe retinal tear.

Appearance of Lattice Degeneration

Lattice typically appears as elongated or oval peripheral retinal lesions.

Common features include:

• Linear orientation
• Location anterior to the equator
• Orientation roughly parallel to the ora serrata
• Retinal thinning
• Pigmentary changes
• White vascular sclerosis
• Branching white lines
• Small atrophic holes

The appearance can vary considerably from one patient to another.

Retinal Thinning

The retina within the lattice area may appear:

• Thin
• Gray
• Translucent
• Atrophic

The edges may be more heavily pigmented.

White Lines

Branching white lines may cross the lesion.

These represent sclerosed retinal vessels and contribute to the classic lattice-like appearance.

Atrophic Holes

Small round holes may develop within areas of lattice degeneration.

These are usually caused by progressive thinning rather than acute vitreous traction.

Most asymptomatic atrophic holes associated with lattice do not require treatment.

Peripheral Retinal Examination

A careful peripheral examination, often with scleral depression, is important to identify:

• Horseshoe tears
• Atrophic holes
• Small retinal detachments
• Other areas of lattice

The examination should encompass the full retinal periphery.

Differential Diagnosis

Important differential diagnoses include:

• Cobblestone degeneration
• Peripheral retinoschisis
• Microcystoid degeneration
• Chorioretinal scar
• Previous retinal laser scars
• Chronic retinal detachment
• Hereditary vitreoretinal degeneration

Cobblestone Degeneration

Cobblestone or paving-stone degeneration consists of areas of peripheral chorioretinal atrophy.

Unlike lattice degeneration, it generally does not carry the same association with retinal tearing and detachment.

Peripheral Retinoschisis

Degenerative retinoschisis represents splitting of the retinal layers.

It may mimic peripheral retinal elevation or degeneration but differs from lattice in morphology and pathophysiology.

Stickler Syndrome

Stickler syndrome is an important inherited vitreoretinal disorder associated with a high risk of retinal detachment.

Features may include:

• High myopia
• Abnormal vitreous
• Lattice-like retinal degeneration
• Cataract
• Midface hypoplasia
• Small chin
• Cleft palate or bifid uvula
• Hearing abnormalities

Common genetic causes include mutations involving COL2A1 and COL11A1.

Treatment

Asymptomatic Lattice Degeneration

Most asymptomatic lattice degeneration requires observation only.

Routine prophylactic laser treatment is generally not indicated solely because lattice is present.

This remains true for many cases in which small atrophic holes are found within the lattice but there is:

• No progressive subretinal fluid
• No associated symptomatic tear
• No retinal detachment

Symptomatic Patients

A patient with new flashes or floaters requires a careful dilated retinal examination because symptoms may indicate:

• Acute PVD
• Retinal tear
• Early retinal detachment

The presence of symptoms does not automatically mean the lattice itself should be lasered.

Treatment is directed primarily at clinically significant retinal breaks or other high-risk findings.

Retinal Tears

A symptomatic tractional retinal tear is generally treated with:

• Laser retinopexy
• Cryoretinopexy in selected cases

The goal is to create a chorioretinal adhesion around the tear and reduce progression to retinal detachment.

Prophylactic Laser for Lattice

Prophylactic treatment may be considered selectively in patients with particularly high-risk circumstances, such as:

• Retinal detachment in the fellow eye
• Certain hereditary vitreoretinopathies
• High-risk retinal breaks within lattice
• Progressive subretinal fluid
• Other special circumstances determined by a retina specialist

Routine treatment of all lattice degeneration is not recommended.

Retinal Detachment

If a retinal detachment develops, treatment depends on:

• Location
• Extent
• Type of retinal break
• Lens status
• Vitreous anatomy

Possible procedures include:

• Pneumatic retinopexy
• Scleral buckle
• Pars plana vitrectomy
• Combination surgery

Referral

Referral to a retina specialist is appropriate when there is:

• Symptomatic retinal tear
• Retinal detachment
• Suspicious peripheral retinal break
• Progressive subretinal fluid
• Significant high-risk fellow-eye history
• Hereditary vitreoretinal disease

Follow-Up

Follow-up intervals depend on:

• Extent of lattice degeneration
• Presence of retinal holes
• Symptoms
• Degree of myopia
• Fellow-eye history
• Family history
• Presence of PVD

Patients with high myopia or previous retinal detachment in the fellow eye may warrant closer surveillance.

Patient Education

Patient education is extremely important.

Patients should seek urgent ophthalmic assessment if they develop:

• New flashes
• Sudden onset of multiple floaters
• A shower of black dots
• A curtain or veil in the vision
• New peripheral field loss
• Sudden decrease in visual acuity

These symptoms may represent a retinal tear or detachment.

Prognosis

The overall prognosis for isolated lattice degeneration is excellent.

Most patients never develop retinal detachment.

The absolute risk of detachment in an eye with lattice but without prior detachment in the fellow eye is relatively low.

The prognosis changes substantially if a retinal tear or detachment develops.

Complications

The major complications are:

• Atrophic retinal holes
• Horseshoe retinal tears
• Rhegmatogenous retinal detachment
• Permanent visual loss if retinal detachment involves the macula or treatment is delayed

The key clinical pearl is: lattice degeneration itself is usually observed, but new flashes, floaters, or a visual-field curtain require urgent retinal examination because these symptoms may indicate a retinal tear or detachment.