Peripheral Retinal Degeneration

Key points at a glance

Key Points at a Glance

• Peripheral retinal degeneration is a general term for degenerative changes occurring from the ora serrata to the equator; most are benign and asymptomatic.
• Lattice degeneration is found in 5–10% of adults and is associated with approximately 40% of eyes with rhegmatogenous retinal detachment (RRD).
• If a symptomatic retinal tear is left untreated, more than half may progress to RRD. ¹⁾
• Laser photocoagulation can reduce the risk of RRD to less than 5%. ¹⁾
• Indirect ophthalmoscopy with scleral depression is recommended as the standard technique for diagnosis. ¹⁾
• In an 11-year follow-up of 423 eyes with lattice degeneration, only 3 eyes progressed to clinical RRD. ¹⁾
• If floaters or photopsia appear suddenly, prompt ophthalmologic evaluation is necessary.

1. What is Peripheral Retinal Degeneration?

Peripheral retinal degenerations are a diverse group of degenerative changes occurring in the peripheral retina from the ora serrata to the equator. Most are benign and asymptomatic, and their frequency increases with age.

They are classified into three groups based on the anatomical depth of the lesion.

Intraretinal Degeneration

Definition: Degeneration confined to the retinal layers.

Representative diseases: Lattice degeneration, snail track degeneration, cystic degeneration, retinal tufts.

RRD risk: Lattice degeneration and tractional retinal tufts carry a risk through tear formation.

Vitreoretinal degeneration

Definition: Degeneration occurring at the interface between the retina and vitreous.

Features: Strong vitreous adhesion at the edge of lattice degeneration is a typical example.

RRD risk: The risk of tear formation increases due to interaction with posterior vitreous detachment (PVD).

Chorioretinal degeneration

Definition: Degeneration involving the retinal pigment epithelium and choroid.

Representative disease: Cobblestone degeneration.

RRD risk: By itself, the risk of RRD is low.

Many degenerations are physiological changes and are often discovered incidentally during regular check-ups or examinations for other diseases. However, certain types can cause retinal tears and retinal detachment, so appropriate management is necessary.

Q Does everyone have peripheral retinal degeneration?

A

Peripheral cystoid degeneration is a physiological change found in almost all adults, and cobblestone degeneration is present in 4–28% of adults. Lattice degeneration is seen in 5–10%. However, only a small proportion progresses to RRD, and the majority only require observation.

2. Main symptoms and clinical findings

Subjective symptoms

The majority of peripheral retinal degenerations are asymptomatic and are discovered incidentally during regular check-ups or examinations for other diseases.

If the following symptoms appear, there may be a tear formation or retinal detachment.

• Floaters: Symptoms caused by vitreous opacities. Occur with posterior vitreous detachment (PVD) or vitreous hemorrhage.
• Photopsia (flashes of light): Sensation of flashes when the vitreous pulls on the retina. A warning sign of retinal tear formation.
• Visual field defect: Appears when retinal detachment occurs. If the detachment extends to the fovea, it is accompanied by vision loss.
• Sudden increase in floaters: May indicate vitreous hemorrhage and requires emergency evaluation.

Clinical Findings

Characteristic findings of major peripheral retinal degenerations are shown below.

Lattice degeneration

• Found in 5–10% of adults. More frequent in myopic eyes.
• Characterized by retinal thinning, lattice-like white lines (hyalinized blood vessels), and pigmentation.
• Strong vitreous adhesion at the margins, which can lead to both atrophic holes and tractional tears.
• Approximately 40% of eyes with RRD have lattice degeneration. However, the incidence of RRD in lattice degeneration itself is only 0.3–0.5%.

Snail track degeneration

• Found in about 10% of the general adult population and about 40% of myopic eyes.
• Characterized by shiny white dots arranged like a snail track.
• Considered a subtype or precursor of lattice degeneration.

Cobblestone degeneration

• Found in 4–28% of adults. Frequency increases with age, high myopia, and peripheral vascular disease.
• Discrete, pale yellowish-white atrophic spots arranged in a cobblestone pattern in the periphery.
• Caused by atrophy of the retinal pigment epithelium and outer retina due to focal loss of choriocapillaris.
• Low risk of RRD.

Retinal tufts

• The most common degeneration, found in up to 72% of adults.
• Classified into three types: cystic, non-cystic, and tractional.
• Tractional retinal tufts adhere strongly to the vitreous and are prone to form tractional tears during posterior vitreous detachment.

Cystoid degeneration

• A physiological change found in almost all adults.
• Cavities form in the outer plexiform layer, which may progress to peripheral retinoschisis.

Q How often is a tear found in posterior vitreous detachment with vitreous hemorrhage?

A

In posterior vitreous detachment with vitreous hemorrhage, a retinal tear is found in about 70% of cases, requiring immediate examination. Prompt detailed fundus examination under mydriasis (see “Diagnosis and Testing Methods”) is important.

3. Causes and Risk Factors

The main causes and risk factors of peripheral retinal degeneration are as follows.

• Aging: The most basic factor. Cystoid degeneration and paving stone degeneration increase in frequency with age.
• Myopia: Increases the frequency of lattice degeneration and snail track degeneration. Mechanical stretching of the peripheral retina due to elongation of the axial length is involved.
• Posterior vitreous detachment (PVD): A direct trigger for tractional tear formation.
• Genetic predisposition: Lattice degeneration is frequently associated with connective tissue diseases such as Stickler syndrome and Wagner syndrome, leading to a high risk of juvenile RRD.
• Trauma: Can cause acute changes (dialysis) due to blunt ocular trauma.
• Choroidal circulatory insufficiency: A major cause of paving stone degeneration. Peripheral vascular disease and hypertension are involved.

Prevention and Daily Care

Although it is difficult to prevent peripheral retinal degeneration itself, paying attention to the following points can help detect progression to retinal detachment early.

• If you experience a sudden increase in floaters or photopsia, promptly consult an ophthalmologist.
• If you have high myopia, undergo regular fundus examinations to check for degeneration.
• If there is a family history of connective tissue diseases such as Stickler, it is recommended to have fundus examinations from a young age.

4. Diagnosis and Examination Methods

Diagnosis of peripheral retinal degeneration requires examination techniques that allow detailed observation of the peripheral retina.

Basic Examinations

• Indirect ophthalmoscopy + scleral depression: Standard method for examining the peripheral retina. The AAO PPP guidelines recommend indirect ophthalmoscopy with scleral depression. ¹⁾ Scleral depression allows detailed observation of degeneration and tears near the ora serrata.
• Dilated slit-lamp biomicroscopy with three-mirror lens: Allows observation up to the anterior periphery. Use the peripheral lens of the three-mirror lens.
• Ultra-widefield fundus camera: Enables wide-field fundus photography without or with minimal dilation. Useful for documenting degeneration and comparing over time.

Ancillary Tests

• Optical coherence tomography (OCT): Confirms retinal thinning and cystic changes in lattice degeneration. Wide-angle OCT allows observation of peripheral tomographic images that were previously difficult to obtain.
• Fluorescein angiography (FA): Confirms non-perfusion areas within lattice degeneration and choroidal circulation abnormalities.
• Fundus autofluorescence (FAF): Used adjunctively to evaluate RPE changes.

Follow-up Recommendations

The AAO PPP guidelines (2019) recommend the following follow-up intervals. ¹⁾

Type/Status of Degeneration	Recommended Follow-up Interval
Asymptomatic atrophic hole	Every 1–2 years
Asymptomatic lattice degeneration	Every 1–2 years
Symptomatic / post-treatment retinal tear	2–4 weeks after treatment, then regularly
High risk (strong vitreous traction, history of RRD in fellow eye)	Shorter intervals

5. Standard Treatment

The treatment strategy for peripheral retinal degeneration depends on the type of degeneration, presence of symptoms, status of retinal breaks, and patient background.

Observation

Most peripheral retinal degenerations are benign, and observation is the basic approach.

• Asymptomatic lattice degeneration and atrophic holes are often managed with regular observation alone.
• In a long-term follow-up study cited by the AAO PPP guidelines, 423 eyes with lattice degeneration were observed for approximately 11 years. Atrophic holes developed in 35%, but only 3 eyes progressed to clinical RRD. ¹⁾

Laser Photocoagulation (Prophylactic Laser)

Indications for Treatment

The indication for prophylactic laser varies by individual case. It is determined based on symptoms, risk factors, and the status of the fellow eye.

Lesions that are more likely to be indicated

• Symptomatic retinal breaks (breaks within lattice degeneration with floaters and photopsia, horseshoe tears)
• Retinal tears in patients with a history of RRD in the fellow eye
• Retinal tears in aphakic or pseudophakic eyes
• Prophylactic treatment before vitrectomy

Treatment efficacy

Laser treatment of symptomatic tears reduces the risk of RRD to less than 5%. ¹⁾ In contrast, more than half of untreated symptomatic tears may progress to RRD. ¹⁾

For isolated retinal tears, photocoagulation around the tear alone is sufficient, but for tears at the edge of lattice degeneration, the tear and the entire degenerative area must be surrounded. Follow-up at 2–4 weeks after treatment is recommended. ¹⁾

Treatment of retinal detachment

Surgery is required when degeneration progresses to retinal detachment.

• Scleral buckling (encircling band): Compresses the tear from the outside to achieve reattachment. Indicated for relatively young patients without advanced vitreous liquefaction.
• Vitrectomy (PPV): Indicated for extensive RRD, macular detachment, and cases with proliferative vitreoretinopathy.
• Pneumatic retinopexy: Can be performed as an outpatient procedure for simple RRD with superior tears. Outcomes may be slightly inferior to buckling or PPV.

Q I was told I have lattice degeneration. Do I need surgery?

A

Asymptomatic lattice degeneration alone usually requires only regular observation, not surgery. In a long-term follow-up of 423 eyes, only 3 progressed to RRD. ¹⁾ However, if floaters or photopsia appear, prompt evaluation for tears is important.

6. Pathophysiology and detailed mechanisms

Mechanism of lattice degeneration

Lattice degeneration results from a combination of multiple tissue changes.

• Retinal vascular occlusion: Small blood vessels within the lesion disappear and are observed as lattice-like white lines (hyalinized vessels). Vascular occlusion reduces nutrient supply to surrounding tissues.
• Retinal thinning: Progressive thinning from the inner to outer layers occurs, leading to atrophic holes.
• Enhanced vitreous adhesion at the margin: At the lesion margin, adhesion to the vitreous is strong, and traction during posterior vitreous detachment progression often causes horseshoe tears (flap tears).

Progression from cystoid degeneration to retinoschisis

Cystoid degeneration is a condition in which cavities form in the outer plexiform layer (Henle fiber layer). When cavities enlarge and separate the inner and outer layers, it becomes peripheral retinoschisis. Unless a hole forms in the outer layer, the risk of RRD is low, but if holes occur in both inner and outer layers, it can progress to RRD.

Pathogenesis of paving stone degeneration

Localized occlusion of the choriocapillaris causes ischemic atrophy of the RPE and outer retina. The atrophic areas appear paler than the surrounding tissue with well-defined borders and often cluster in a cobblestone pattern. The retina within the degenerative lesions adheres firmly to Bruch’s membrane, and vitreous adhesion is minimal, so direct involvement in RRD is low.

Pathways of retinal detachment development

There are two pathways for the development of rhegmatogenous retinal detachment (RRD) based on peripheral retinal degeneration. ¹⁾

• Atrophic hole pathway: Retinal thinning within lattice degeneration progresses, forming round retinal holes (atrophic holes). When vitreous liquefaction advances, subretinal fluid inflow leads to RRD. This is more common in younger individuals and progresses relatively slowly.
• Tractional tear pathway: During posterior vitreous detachment progression, traction concentrates at the adhesion sites at the margin of lattice degeneration or tractional retinal tufts, forming horseshoe tears. This often rapidly progresses to RRD.

7. Latest research and future perspectives (research-stage reports)

For patients: Please read this

The following content is currently at the research stage or under clinical trial and is not standard treatment available at general hospitals. It is reference information for professionals regarding future medical developments.

Evidence on the Long-Term Natural Course of Lattice Degeneration

In the long-term follow-up study of lattice degeneration cited by the AAO PPP guidelines (2019), 423 eyes were followed for an average of approximately 11 years. Atrophic holes developed in 35%, but only 3 eyes progressed to clinical RRD. ¹⁾ This result supports the validity of observation for asymptomatic lattice degeneration.

Peripheral Retinal Evaluation with Wide-Field OCT

Advances in wide-field optical coherence tomography (wide-field OCT) now allow real-time, non-invasive evaluation of tomographic images of the peripheral retina, which was previously difficult to observe. Studies are underway to quantify the degree of lamellar thinning, cystic changes, and separation in lattice degeneration, and its application to RRD risk prediction is expected.

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8. References

1. AAO Retina/Vitreous Panel. Posterior Vitreous Detachment, Retinal Breaks, and Lattice Degeneration Preferred Practice Pattern. San Francisco: American Academy of Ophthalmology; 2019.

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2. Cheung R, Ly A, Katalinic P, Coroneo MT, Chang A, Kalloniatis M, et al. Visualisation of peripheral retinal degenerations and anomalies with ocular imaging. Semin Ophthalmol. 2022;37(5):554-582. PMID: 35254953.
3. Venkatesh R, Sharief S, Thadani A, Ratra D, Mohan S, Narayanan R, et al. Recommendations for management of peripheral retinal degenerations. Indian J Ophthalmol. 2022;70(10):3681-3686. PMID: 36190072.