Behind the Curtain of Retinal Detachment – Saving the Vision

abidamozid21
4 hours ago
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Figure 1: Superior rhegmatogenous retinal detachment (RRD), macula-off, and a horseshoe tear located at 12 o’clock.⁽¹⁴⁾

Written by Abida Mozid, BSc Biomedical Science

What is a Retinal Detachment?

Retinal detachment is a sight-threatening condition that is caused by the retina separating from the back of the eye. This is classed as a medical, ocular emergency, as prevention of permanent vision loss depends on the time taken from symptom onset up to diagnosis and treatment. ^(1,5)

Symptoms of Retinal Detachment

Pain does not usually occur with the onset of retinal detachment. This is why prompt medical assessment is urgent if any of the following symptoms appear ⁽¹⁾:

- Blurred &/or distorted vision

- Veil or curtain-like shadow over your field of vision

- Reduced peripheral vision

- Sudden appearance or increase of flashing lights in vision

- Sudden appearance or increase of floaters in vision

Factors of Predisposition:

- Family history

- Previous cataract surgery

- Extreme myopia

- History of previous retinal detachment

- Smoking

How does this Affect the Vision?

This involves the neurosensory retina, which is where light is detected via the photoreceptor cells. The retina is attached to the retinal pigment epithelium (RPE), which provides oxygen and nutrients from a layer of vessels called the choroid. ⁽¹⁵⁾

When detachment occurs, the neurosensory retina no longer receives the choroidal blood supply to provide the necessary oxygen and nutrients. This means that the photoreceptor cells can begin to degenerate without this supply, causing visual function to decline. The RPE also pumps fluid away from the retina, so if the neurosensory retina detaches, the fluid can accumulate which will worsen the separation.

The neurosensory retina can recover after treatment, but this depends on:

- the duration of the detachment

- extent of the damage to the photoreceptors

- whether the macula (the central part of the neurosensory retina responsible for detailed vision) was involved

If the neurosensory retina is reattached in a quick timeframe, photoreceptors may regain their function. If detachment is prolonged and the macula detaches (known as macula off retinal detachment), central vision loss can be severe as photoreceptor damage can become permanent. This is why retinal detachment is considered time sensitive, so this irreversible cell loss is avoided. ⁽¹⁵⁾

All forms of retinal detachment will ultimately involve separation of the neurosensory retina from the RPE, leading to visual impairment.

What are the Types of Retinal Detachment

1. Rhegmatogenous Retinal Detachment

This is the most common form of retinal detachment which typically occurs over time and is associated with a retinal tear or hole. ^(5,9) So how does this lead to the retina detaching?

Inside of the eyes, there is a gel-like material called the vitreous occupying most of the space in front of the retina, keeping it pressed against the back of the eyes. As people age, the vitreous undergoes changes that make it shrink and become more liquid (vitreous liquefication).

Pockets of fluid can form inside the eyes, a process called vitreous syneresis. As these pockets merge and the vitreous becomes softer, opacities can float inside the gel, casting shadows on the retina. This is what explains the symptoms of floaters in the vision.

As the vitreous contacts and undergoes syneresis, it can detach from the back wall of the eye, therefore separating from the retina. This is called Posterior Vitreous Detachment (PVD). PVD is extremely common and harmless. ⁽¹⁰⁾

When is it an emergency?

Anomalous PVD occurs when the vitreous is more attached than normal at the base of the retina. So, when the vitreous tries to detach from areas of the retina, this causes traction. Excessive traction can occur in certain areas of the retina, and this can trigger a tear or a break due to the pulling force. ⁽³⁾ Without early intervention, the risk of the tear worsening increases for the patient.

The fluid inside the eye then passes into the space beneath the retina and then the retina begins to detach from the peripheral area. This process of detachment tends to progress.

This is why detecting new or sudden increase in floaters and/or photopsia (flashing lights) in the vision is important, as recognising higher risk patients with anomalous PVD allows for earlier intervention. ^{(9, 10)}

2. Tractional Retinal Detachment

This is the second most common type of detachment and occurs when scar tissue develops inside of the eye. ⁽⁶⁾ As the scar tissue contracts, it pulls on the retina, causing it to separate from the back the eye. A retinal tear or hole does not need to form for tractional retinal detachment to be triggered, however certain patients can experience both causes. Such cases are classed as tractional-rhegmatogenous retinal detachments. ⁽⁴⁾

So where does the scar tissue come from?

Diabetic retinopathy, a condition where blood vessels of diabetic patients become damaged, is the leading cause of tractional retinal detachment. ⁽⁴⁾ Due to the damaged blood vessels, oxygen supply to the retina becomes reduced, a mechanism called retinal ischaemia. Other causes include previous injury or surgery to the eye, chronic eye inflammation (e.g. Uveitis, retinal vasculitis) and retinal vein occlusion.

As the retina is sensitive to decreased oxygen levels, the retinal cells release a growth factor called Vascular Endothelial Growth Factor (VEGF). This is in attempt to form new, protective vessels along the retina; however, these vessels develop abnormally and are weaker (neovascularisation). ^{(2, 4)}

Growing alongside the new vessels is the scar tissue which consists of fibrovascular membranes. As the scar tissue shrinks and contracts, this triggers tension as it is also attached to the retina. This pulling force is what gradually causes the retina to be lifted upwards and separate without a tear or hole. Tractional retinal detachment can take much longer to progress, typically over a period of months or years. ^{(3, 6)}

3. Exudative Retinal Detachment

This form of detachment is characterised by the accumulation of fluid between the neurosensory retina and the RPE, causing the retina to lift away from the back of the eye. This process does not involve scar tissue or a retinal tear/hole.

There are certain conditions which can trigger fluid leakage amongst the RPE and the choroid, including:

- Severe high blood pressure

- Central serous chorioretinopathy

- Tumours (e.g. Choroidal melanoma)

- Autoimmune disease involvement, specifically uveitis, Vogt-Koyanagi-Harada (VKH) disease, and posterior scleritis ^(7,12)

As the choroid operates, blood vessels are well-maintained and controlled, with the RPE preventing the fluid from entering the retinal space. If the blood vessels become damaged and chronically inflamed, this can turn them leaky or more permeable. Fluid and blood can then leak from the weakened vessels and begin to collect underneath the retina. If the RPE is also damaged and chronically inflamed, it can become unable to effectively clear the fluid. The buildup of fluid creates enough pressure to eventually lift and separate the retina away from the RPE. ⁽¹⁵⁾

Diagnosis

- Initial examination includes a dilated fundus exam. Eye drops are used to widen the pupil so the clinician will be able to inspect the retina and macula in detail, using a specialised lens and light.

- Optical Coherence Tomography (OCT) is an advanced imaging test which uses light to provide high-resolution, 3D cross-sectional imaging of the retinal layers.

- An ultrasound of the eye (B-scan) uses sound waves to create an image of the eye. The clinician may use this test if bleeding in the eye is making it difficult to see the retina.

- Ultra-wide field retinal imaging (UWF photography) provides digital images that capture over 200 degrees of the retina. ^(6,8)

For rhegmatogenous retinal detachment, clinicians would use dilation to check for any tears or holes. An OCT scan can also aid in assessing any involvement of the macula. UWF photography can capture any peripheral tears.

In patients with tractional retinal detachment, clinicians would check for any scar membranes on the retina during the dilation exam. OCT would be useful to detect any areas of traction or pulling before full detachment. UWF photography can help to assess diabetic or vascular disease across the retina, and an ultrasound can be used if scar tissue or bleeding is obstructing view.

To diagnose exudative retinal detachment, in a dilation exam clinicians may find fluid that is shifting. OCT is highly important for these cases, as it shows if there are any pockets of fluid underneath the retina, alongside RPE abnormalities. Further imaging is often required as well to inspect issues regarding the vessels. An ultrasound can support in detecting tumours or other factors.

Retinal detachment often affects one eye at a time. When diagnosing, it is important that the second eye is thoroughly assessed for any signs of retinal tears or holes that may lead to detachment in the future.

Treatment

- Laser Photocoagulation

This uses a laser to seal off the area of the tear, forming a scar to prevent the retina from detaching. It’s used when the retina is detached but the macula is still attached (macula-on detachment) and for earlier and smaller tears.

- Cryopexy

This involves freezing the area around the tear to form a scar, as a laser procedure would.

- Pneumatic Retinopexy

A gas or air injection supplies a bubble into the eye, which presses the retina against the RPE as the tear is sealed via laser or cryopexy.

- Vitrectomy

The vitreous gel is taken out and the fluid drained so the retina can be repositioned. The surgeon then replaces the fluid with a gas or silicone oil bubble to keep the retina in position. This is more ideal for patients with tractional form of detachment, due to the presence of scar tissue.

- Scleral Buckling

A band can be placed around the outer eye to push the wall against the detached retina. This is more ideal for younger patients or those with peripheral retinal tears. ^{(13, 15)}

For exudative retinal detachment, the treatment will depend on the underlying cause of fluid leakage. Once the condition causing it is diagnosed and addressed, this should resolve the detachment. Surgery is rarely required for these cases.

Why does surgery have to be urgent?

The retina is made up of neurons, so when there is damage to nerve cells, there is a high risk of long-term lasting damage. With early and urgent intervention, ophthalmologists have a chance to treat the detachment before it reaches the macular region. The patient is more likely to leave the surgery without long-term effects and completely normal vision. If the detachment is macula-off but for a short period, especially within the first 3 days, the same outcome is likely, or the patient may have minimal to no lasting effects on the vision. ^(2,11)

If a prolonged amount of time is taken to diagnose the detachment and treat it, there is high risk of some level of lasting effects. Early diagnosis and repair are vital, as visual impairment is reduced when the retina is fixed before the central area is detached.

References

1. Nih.gov. (2024). Types and Causes of Retinal Detachment | National Eye Institute. [online] Available at: https://www.nei.nih.gov/eye-health-information/eye-conditions-and-diseases/retinal-detachment/types-and-causes-retinal-detachment.

2. ‌ Mishra, C. and Tripathy, K. (2021). Retinal Traction Detachment. [online] PubMed. Available at: https://www.ncbi.nlm.nih.gov/books/NBK558952/.

3. ‌ American Academy of Ophthalmology. (2022). What Is Vitreomacular Traction? [online] Available at: https://www.aao.org/eye-health/diseases/what-is-vitreomacular-traction.

4. ‌ Kim, L.A., Wong, L.L., Amarnani, D.S., Bigger-Allen, A.A., Hu, Y., Marko, C.K., Eliott, D., Shah, V.A., Declan McGuone, Stemmer-Rachamimov, A.O., Gai, X., D’Amore, P.A. and Arboleda-Velasquez, J.F. (2015). Characterization of cells from patient-derived fibrovascular membranes in proliferative diabetic retinopathy. Molecular Vision, [online] 21, p.673. Available at: https://pmc.ncbi.nlm.nih.gov/articles/PMC4462955/.

5. ‌ Kuhn, F. and Aylward, B. (2014). Rhegmatogenous retinal detachment: a reappraisal of its pathophysiology and treatment. Ophthalmic Research, [online] 51(1), pp.15–31. doi:https://doi.org/10.1159/000355077.

6. ‌ Sissons, B. (2024). What is tractional retinal detachment? [online] Medicalnewstoday.com. Available at: https://www.medicalnewstoday.com/articles/tractional-retinal-detachment.

7. ‌ Eyewiki.org. (2024). Vogt-Koyanagi-Harada Disease - EyeWiki. [online] Available at: https://eyewiki.org/Vogt-Koyanagi-Harada_Disease.

8. ‌ OD, B.J.T., OD, and Brad Sutton (2023). Ultra-Widefield Imaging: Expand Your Horizons. [online] www.reviewofoptometry.com. Available at: https://www.reviewofoptometry.com/article/ultrawidefield-imaging-expand-your-horizons.

9. Kang, H.K. and Luff, A.J. (2008). Management of retinal detachment: a guide for non-ophthalmologists. BMJ : British Medical Journal, [online] 336(7655), pp.1235–1240. doi:https://doi.org/10.1136/bmj.39581.525532.47.

10. Gishti, O., Nieuwenhof, R., Verhoekx, J. and Overdam, K. (2019). Symptoms related to posterior vitreous detachment and the risk of developing retinal tears: a systematic review. Acta Ophthalmologica, 97(4), pp.347–352. doi:https://doi.org/10.1111/aos.14012.

11. ‌ Retinal Detachment: What Is a Torn or Detached Retina (2016). Retinal Detachment: What Is a Torn or Detached Retina? [online] American Academy of Ophthalmology. Available at: https://www.aao.org/eye-health/diseases/detached-torn-retina.

12. ‌ Admin (2024). Associated Retina Consultants. [online] Associated Retina Consultants. Available at: https://associatedretinaconsultants.com/how-do-autoimmune-diseases-affect-the-retina/.

13. Admin (2025). Associated Retina Consultants. [online] Associated Retina Consultants. Available at: https://associatedretinaconsultants.com/retinal-detachment-signs-emergency-response-and-treatment-approaches-2/.

14. ‌Abadia, B., Desco, M.C., Mataix, J., Palacios, E., Navea, A., Calvo, P. and Ferreras, A. (2020). Non-Mydriatic Ultra-Wide Field Imaging Versus Dilated Fundus Exam and Intraoperative Findings for Assessment of Rhegmatogenous Retinal Detachment. Brain Sciences, [online] 10(8). doi:https://doi.org/10.3390/brainsci10080521.

15. www.sciencedirect.com. (n.d.). Retinal Detachment - an overview | ScienceDirect Topics. [online] Available at: https://www.sciencedirect.com/topics/medicine-and-dentistry/retinal-detachment.

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