Saturday, 22 February 2020

BLIND SPOT EYES

BLIND SPOT


Definition


“This is blind spot eyes. This loss of vision is secondary to the central retinal artery. This blind spot of the right eye is located on the right side of the center of vision and is a direct result of percutaneous injection for aesthetics in the left eye.  ”

Blindness after facial injection is extremely rare and was first reported by von Bahr over 50 years ago after scalp injection of a hydrocortisone suspension to treat alopecia. The first cases after aesthetic filler treatments were reported in the 1980s (four cases) and rose to at least 16 reported cases between 2000-2010, presumably related to the increase in the number of treatments being performed.

Depending on which artery is occluded, vision loss can be classified into six subtypes:
1. Ophthalmic artery occlusion (OAO)

2. It is normally arterial with the relative backward. central retinal artery sparing (PCAO)

3. Central retinal artery occlusion (CRAO)

4. Branch retinal artery occlusion (BRAO)

5. Anterior ischaemic optic neuropathy (AION)

6. Posterior ischaemic optic neuropathy (PION)

There are also four types of periocular complications associated with as blindness following cosmetic filler injections:
Type I – Blindness is without ophthalmoplegia paralysis or the weakness of ocular muscles and ptosis
Type II –  Ptosis blindness but without ophthalmoplegia
Type III – Blindness with is ophthalmoplegia but without ptosis
Type IV – Blindness within ophthalmoplegia and ptosis
This blind eye spot based on previously reported to the case studies, improvement of visual acuity in patients with vascular occlusion after filler injection is extremely rare.

MECHANISM

There is a mechanism to the terminal branches of the ophthalmic artery, namely the supraorbital medial forehead and anastomoses between these vessels and the terminal branches of an angular artery are well documented. Similarly, anastomoses with the superficial temporal arteries and the orbit have also been demonstrated. Injection of filler material into one of these vessels may lead to retrograde flow to beyond the point of the origin of the ophthalmic artery, and when pressure from the plunger is released, systolic pressure drives the product forward and to enter the ophthalmic artery or central retinal artery resulting in visual loss.

The requirements for blindness to occur include the retrograde and subsequent anterograde passage of material, injection pressure exceeding systolic pressure and a sufficient amount of material within the lumen of the vessel.

INCIDENCE

Globally at least 98 cases of visual loss after aesthetic facial injection have been reported prior to 2015. A review of the world literature by Belezany 12 identified 98 cases of vision change. High-risk areas were glabella (38.8%), nasal region (25.5%), nasolabial fold (13.3%), and forehead (12.2%). Autologous fat was responsible for most of the complications (47.9%) followed by hyaluronic acid (23.5%) 12 and the outcome was worse in cases when autologous fat had been injected.


SIGNS AND SYMPTOMS

Visual loss following embolization of dermal filler typically occurs within seconds of injection 7, although visual loss has been reported seven hours post-treatment in the case of posterior ciliary artery occlusion. Complete loss of vision is the normal presentation, although there may be visual field defects. Visual loss is often accompanied by sudden onset of severe pain (ocular, facial, headache or any combination) although central retinal and retinal branch artery occlusions may present without ocular pain. Other symptoms include ophthalmoplegia (paralysis or weakness of ocular muscles), ptosis, enophthalmos (posterior displacement of the eye) and horizontal strabismus (abnormal alignment of the eyes).

BLIND SPOT


Many cases with visual loss and periocular symptoms also subsequently developed enophthalmos and surgery could be considered in patients demonstrating greater than 2mm descent within six weeks of the injury. Other symptoms include corneal edema, swelling of the anterior chamber, nausea, headache, pupil abnormality, iris atrophy, Fethys bulbs, and Leo reticules. Retinal artery occlusion may also occur with cerebral infarction, so symptoms may also be present, such as contraceptive bleeding. Central nervous complications were seen in 23.5% 12 to 39% 5 of cases where the vision was affected. An MRI scan should be performed in all patients who suffer visual loss or ocular pain because of filler injections 10.

  • Visual loss (complete or partial)
  • Pain (ocular, facial, headache or a combination)
  • Paralysis or weakness of ocular muscles
  • Nausea
  • Ptosis
  • Posterior displacement of the eye
  • Strabismus (misalignment of the eyes when looking
  • at an object)
  • Corneal edema
  • Pupillary abnormality
  • Iris atrophy
  • Anterior chamber inflammation
  • Phthisis Bulbs (shrunken, non-functional eye)
  • Livedo reticularis (a mottled, reticulated vascular a pattern of the skin)


AREAS OF CAUTION

Injections into the nose and glabella formed the clear majority of reported cases of blindness, although moderate risk sites included the nasolabial folds, forehead, periocular region, temple, and cheek. Uncommon sites were the eyelids, lips, and chin. Due to the complex vascularity of the face, any region has the potential to cause this complication.

MINIMIZING THE RISK

The key preventative strategies are listed below :
1. Know the location and depth of facial vessels and the common variations. Different sites of injectors must understand the proper depth and plane of injection.

2. Inject slowly and with minimal pressure.

3. Inject in small increments so that any filler injected into the artery can be flushed peripherally before the next injection. This prevents retrograde travel to a column of the depth of the spot. No more than 0.1 ml of filler should be injected at one time.

4. Move the needle tip while injecting, so as not to deliver a large deposit in one location.

5. Aspirate before injection.  This recommendation is controversial as it may not be possible to get flashbacks into a syringe through fine needles with thick gels.

6. Use a small-diameter needle. A smaller needle necessitates slower injection and is less likely to occlude a vessel. If a sharp needle is being used, then a perpendicular injection directly in contact with the bone is recommended. Injecting into a deeper plane may avoid vessel.

7. Smaller syringes are preferred to larger ones, as a large syringe may make it more challenging to control the volume and increases the probability of injecting a larger bolus.

8. Consider using a cannula (25 gauge or greater bore size), as they are less likely to pierce a blood vessel. Some authors recommend the use of the cannula in the medial cheek, tear trough, and nasolabial fold.

9. Use extreme caution when injecting a patient who has undergone trauma or a previous surgical procedure in the area.  

10. Ensure that you are adequately trained, using an appropriate product and are competent in the area in which you are treating as well as competent in the management of complications.

11. A technique to possibly prevent embolism of filler is digital compression of the inferior-medial orbital rim and the side of the nose while injecting.

Sometimes the ophthalmic artery does not arise normally from the internal carotid artery, but from the middle meningeal artery, which originates from the external carotid artery. In addition, it is one such superficial temporal artery in the zygomatic-orbital artery that has branches of the ophthalmic artery and perhaps a retrograde artery via the embolic root. Facial anatomy can be diverse. The facial artery originated from a single arterial trunk in 86% of specimens, and branching patterns were only symmetrical in 53% of cases. In conclusion, there is no absolute safe area of the face to inject.

TREATMENT OF BLINDNESS AFTER FACIAL INJECTION

Once the retinal artery has been occluded there is a window of 60-90 minutes before blindness is irreversible. It is essential to transfer the patient to the nearest specialist eye hospital via a blue light ambulance as quickly as possible. Transfer to a non-specialist emergency department may lead to inordinate delay and a worse outcome. Ensure that you know where your closest specialist eye department is and contact the on-call team as soon as possible to inform them of the situation. Give the medical staff as much information as possible about the product, area and injection volume. It is very important that people who work in this field.

Although there is no generally agreed treatment regimen, there are actions that may help. A safety blindness safety kit 'along with a six-step therapy protocol is suggested that can be used in a clinical setting and then released in hospital. The protocol was adapted from Lazzeri et al.

TREATMENT OF VISUAL LOSS AFTER FACIAL FILLERS

Indications for treatment are sudden onset ocular pain and/ or loss of vision. The endocrine pressure is to be reduced early so that emboli can migrate downstream and improve retinal perfusion.


Stop treatment immediately

Place the patient in a supine position.
Call 999 and prepare to transfer a patient to a hospital
setting as soon as possible.
Do not let any of the following measures delay referral to a specialist eye hospital.

Reduce Intraocular Pressure

Administer Timolol 0.5% one-to-two drops in the affected eye only. It works to reduce intrauterine pressure by reducing beta-adrenergic antagonist aqueous production. The patient should be encouraged to rebreathe in a paper bag. The aim is to increase CO2 levels within the blood which will cause retinal arteries to vasodilate and could help dislodge a blockage. An alternative is the inhalation of carbogen (95% oxygen, 5% carbon dioxide). Oral acetazolamide may be considered, although intravenous administration in hospitals is likely to be of greater benefit. Give the patient 300 mg of aspirin to prevent blood clotting.

Do not like an ambulance in a peripheral position

Massage the globe with repeated increasing pressure. Prolonged ocular massage attempts to dislodge emboli by rapidly changing intraocular pressure, thereby changing the pressure and flow in the retinal arteries increasing intraocular pressure leads to retinal artery reflex dilation and releasing it can increase the amount of sudden flow.

Eyes are massaged with the patient looking straight ahead with the eyes closed. Gentle pressure is applied over the sclera with a finger, indenting the globe by a few millimeters and then releasing at a frequency of two-to-three times a second. In general, firm ocular massage is performed for several seconds and is not repeated frequently. 

Administer hyaluronidase


If the hyaluronic acid filler has been used, administer hyaluronidase to the treatment area according to ACE Group guidelines (The Use of Hyaluronidase in Aesthetic Practice). Retrobulbar injection of hyaluronidase has been advocated by many plastic surgeons as emergency treatment, however, an evaluation by Zhu et al 3 failed to show any improvement in visual loss following 1500-3000 units of hyaluronidase injected into the retrobulbar space in four patients. When the topic of retrobulbar hyaluronidase injection is discussed by beauty doctors, it is a technically difficult procedure even for a competent ophthalmologist. The scope for causing more harm means the risks, including perforation of the orbit and hemorrhage, outweigh any benefit.

However,  Chestnut 20 reported in  Dermatologic Surgery that full restoration of vision after blindness was reported in a patient receiving hyaluronic acid fillers in the midface. Sight after three retrobulbar hyaluronidase injections and aspirin. A total of 750 units were administered, with 450 units as retrobulbar injection and 300 units to surround the supraorbital and infraorbital foramina. Injection of hyaluronidase into the supratrochlear or supranormal arteries approaches more to reach the ambiguous. The use of hyaluronidase has been shown to be ineffective at recanalizing the retinal artery occlusion or improving the visual outcome after four hours after the onset of blindness.


Specialist treatment


  • When the patient is hospitalized, the aim is to reduce intracellular pressure, relieve central retinal ischemia, or increase blood flow to the retina.
  • Injection of 500mg IV Acetazolamide. This should increase retinal blood flow and reduce intraocular pressure.
  • Consider the use of Enoxaparin subcutaneously or IV  heparin for anticoagulation.
  • Intravenous infusion of mannitol 20% (100ml over 30 minutes).
  • Consider the injection of hyaluronidase via the trans-orbital approach into the more prominent and tortuous post septal ophthalmic artery.

Other supportive therapies include

  • Anterior chamber paracentesis to immediately lower intraocular pressure.
  • Steroid administration, intravenous dexamethasone.
  • Judicious use of antibiotics for suspected infection.
  • Hyperbaric oxygen may salvage vulnerable retinal damage. 
  • Practitioners should familiarise themselves with their nearest hyperbaric oxygen chamber.
  • Intravenous prostaglandin E1 4 to increase blood flow to the retina and decrease activation of thrombocytes and neutrophils.

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