Retinal tears and detachment

• Summary
• Background
• Clinical presentation
• Risk factors
• Lattice degeneration
• Examination
• Management
• References
• Author(s)

Summary

Normally, the retinal pigment epithelium (RPE) is able to maintain adhesion with the overlying neurosensory retina through the active transport of subretinal fluid across RPE, interdigitation of the photoreceptor outer segments and the RPE microvilli, and it’s own metabolic processes. In retinal detachment, these mechanisms are overwhelmed resulting in separation of the neurosensory (inner layers) retina from the retinal pigment epithelial layer.

Background

This process can occur in three ways:

1. Rhegmatogenous retinal detachment: A break in the retina occurs allowing vitreous to directly enter the subretinal space. Often secondary to a retinal tear associated with posterior vitreous detachment or trauma.
2. Tractional retinal detachment: Proliferative membranes form on the surface of the retina or vitreous. These membranes can pull on the neurosensory retina causing a physical separation between the neurosensory retina and retinal pigment epithelium
3. Exudative retinal detachment: Accumulation of subretinal fluid due to inflammatory mediators or exudation of fluid from a mass lesion.

Clinical presentation

• New onset of flashes and floaters
• Sudden-onset painless, progressive, visual field loss

Risk factors

Lattice degeneration

Lattice degeneration is considered the most important peripheral retinal degeneration process predisposing to a rhegmatogenous retinal detachment. It is present in around 10% of the population. It involves the peripheral retina becoming thinned or atrophic in a lattice pattern, resulting in atrophic retinal holes, retinal tears, and retinal detachments. It presents bilaterally and is an important cause of RD in young myopic individuals.

Examination

• Pupillary reflexes
• RAPD may occur if the macula is detached or if at least two quadrants of the non-macular retina have detached
• Visual acuity
• Poor visual acuity suggests macular detachment or a vitreous haemorrhage
• Visual fields
• Confrontational visual field testing may reveal gross visual defects corresponding to the area of detached retina
• Slit lamp examination of the anterior segment
• An important finding with the slit lamp is the presence of 'tobacco dust', this is associated with a 90% risk of a retinal break, which in turn is associated with a vitreous haemorrhage in 70% of cases. The presence of this pigment is known as Schaffer’s sign.
• Rhegmatogenous retinal detachment has a characteristic appearance: a corrugated appearance that undulates with eye movements.
• Tractional detachments have smooth concave surfaces with minimal shifting with eye movements
• Serous detachments show a smooth retinal surface and shifting fluid depending on patient positioning
• Dilated fundal examination
• A detachment can be seen, often with an associated tear
• Because its view is narrow, examination with the direct ophthalmoscope cannot exclude RD. If you cannot see an RD but suspect it, refer the patient urgently for a slit-lamp examination.
• An important finding with the slit lamp is the presence of 'tobacco dust', this is associated with a 90% risk of a retinal break, which in turn is associated with a vitreous haemorrhage in 70% of cases. The presence of this pigment is known as Schaffer’s sign.
• B-scan: due to haemorrhage of media opacity, limiting the slit lamp view, this can be used to evaluate the retina and vitreous instead.

Management

Surgical management is indicated for rhegmatogenous and tractional detachments.

For rhegmatogenous detachments, all retinal breaks should be identified, treated and closed. Techniques for repair include:

1. Pneumatic retinopexy
1. Involves the injection of an intraocular gas bubble along with retinopexy using cryotherapy or laser, usually in a clinic setting. The gas bubble tamponades the retinal tear.
2. Pneumatic retinopexy is typically only used with retinal detachments due to retinal tears in the superior eight clock hours and involving a single break less than one clock hour
2. Scleral buckles
1. These are silicone bands which are permanently placed around the outside of the globe under the extraocular rectus muscles to relieve traction and support retinal tears. Scleral buckling is combined with retinopexy, typically cryotherapy.
2. This procedure is performed in the operating room.
3. Pars plana vitrectomy
1. This involves removal of the vitreous through cutting the vitreous strands with a vitrectomy machine, and flattening of the retina through a direct intraocular process.

In tractional detachments, the tractional elements (usually epiretinal or subretinal membranes) must be relieved. This is usually cah pars plana vitrectomy, but may be combined with scleral buckling as an adjunct.

For serous detachments, management is nonsurgical, and the underlying inflammatory disease or mass should be treated.

References

1. 1. Salmon, John F., and Jack J. Kanski. Kanski’s Clinical Ophthalmology: A Systematic Approach. Ninth edition, Elsevier, 2020.
2. Habib, Maged S., et al. ‘Refractile Superficial Retinal Crystals and Chronic Retinal Detachment: Case Report’. BMC Ophthalmology, vol. 6, no. 1, Jan. 2006, p. 3. BioMed Central, https://doi.org/10.1186/1471-2415-6-3.
3. Retinal Detachment. Retinal Detachment Symptoms and Info. 14 May 2021, https://patient.info/doctor/retinal-detachment-pro.CloseDeleteEdit
4. ‘Retinal Detachment’. American Academy of Ophthalmology, 19 June 2013, https://www.aao.org/education/image/retinal-detachment-4.CloseDeleteEdit

Author(s)

Dr Sara Memon

Sara is the Co-Founder of Ophtnotes. She is a doctor who graduated from UCL Medical School in London. She won the Allen Goldsmith Prize in Ophthalmology. Sara is also the co-founder of PAMSA: an organisation linking doctors and medical students of Pakistani origin. She’s especially passionate about teaching and education, having presented a workshop she designed herself at the 2019 Annual GMC Conference.