Introduction  

Deep Sclerectomy (DS) is a surgical procedure used to treat medically uncontrolled open-angle glaucoma. It is a non-penetrating filtration procedure developed to avoid postoperative complications of trabeculectomy and to improve the safety of glaucoma surgery. DS is the procedure of choice and the first line of treatment in the early stages of open-angle glaucoma, after the failure of a medication or laser treatment.

Several eye conditions can benefit from deep sclerectomy, and they include:

  • Pigmentary glaucoma
     
  • Normal-tension glaucoma
     
  • Pseudoexfoliative glaucoma
     
  • Glaucoma induced by steroids
     
  • Aphakic and pseudophakic glaucoma
     
  • Uveitic glaucoma due to less inflammation compared to penetrating surgery
     
  • Patients with high myopia who stand a higher chance of choroidal detachment
     

However, the following conditions should not be addressed via deep sclerectomy:

  • Traumatic glaucoma
     
  • Neovascular glaucoma
     
  • Narrow-angle glaucoma
     
  • Eye with a damaged trabeculum
     
  • Congenital and juvenile glaucoma
     
  • Primary and secondary angle-closure glaucoma
     
  • Cases of iridocorneal endothelial (ICE) syndrome
     
  • Glaucoma secondary to increased episcleral venous pressure
     
  • A narrow angle because of its proximity to the iris which can lead to iris incarceration and anterior synechia formation after the procedure

 

Also Known As

  • Non-penetrating deep sclerectomy

 

Before the Procedure

Patients receive adequate information to manage expectations and fears, where the ophthalmologist explains what can be achieved via glaucoma surgery. S/he will explain the advantages and risks of DS surgery and why the patient needs to cooperate in the close postoperative monitoring that follows the procedure.

A family medical history of glaucoma is significant. If the patient is taking medications like anticoagulants, s/he should stop taking them for five days before surgery. The patient will take topical corticosteroids a month before the procedure to reduce conjunctival inflammation. 

Preoperatively, the patient undergoes a complete assessment for several reasons:

  • In the event of an urgent intervention when there is a threat to the central vision
     
  • To check progression rates, which determines the speed with which the surgeon will operate
     
  • The patient may need a fast intervention if it’s a young patient or if 10% of the patient’s central vision is affected by the visual fields
     

The patient will also undergo a complete ophthalmic examination which includes:

  • Gonioscopy
     
  • Visual acuity
     
  • A slit-lamp exam
     
  • Intraocular pressure (IOP)
     
  • Measuring central corneal thickness
     
  • Optical coherence tomography (OCT)
     
  • Checking for a reliable and recent field of vision
     
  • Fundus examination to exclude other retinal diseases
     
  • In case of an existing cataract, cataract surgery can be combined with sclerectomy
     
  • Conjunctiva checks and in case there is a scar, the sclerectomy will be performed at a different location

 

Procedure

In a DS procedure, the surgeon:

  • Opens the Tenon’s capsule and conjunctiva at the limbus to expose the sclera
     
  • Applies antiproliferative agents to the scleral bed
     
  • Applies thorough irrigation
     
  • Fashions a limbus-based scleral flap which s/he extends into the cornea
     
  • Dissects another deep scleral flap to create a thick scleral bed
     
  • Fashions the trabeculo-Descemet's membrane (TDM), extending the dissection into the cornea
     
  • Uses a spatula or sponge to detach the Descemet's membrane
     
  • Uses fine scissors or a blade to excise the deep flap leaving the aqueous to percolate via the trabeculum
     
  • Uses fine forceps to grab the juxta canalicular trabecular meshwork and the inner Schlemm's canal’s wall and pulls them away from the underlying trabeculum
     
  • Sutures an implant into the scleral bed to maintain that space during the initial healing period, and keep the intrascleral space open
     
  • Closes the superficial scleral flap using nylon sutures
     
  • Closes the conjunctiva using vicryl sutures
     
  • Images the surgical site using the anterior segment OCT, which shows the scleral lake, the collagen implant, and the TDM

 

Risks & Complications

DS results in common complications related to filtering surgeries and is generally regarded as a safe procedure. Generally, the risks and complications may include:

  • Bleb leakage
     
  • Intraocular inflammation
     
  • Common and mild hemorrhage
     
  • Hypotony (low IOP) which should resolve within one to two weeks 
     

The following are the DS-related risks and complications:

  • Flat anterior chamber
     
  • Choroidal detachment
     
  • Hypotonic maculopathy
     
  • Intraocular haemorrhage
     
  • Ocular hypertension though rare
     
  • Fluctuations involving intraocular pressure
     
  • Blebitis and endophthalmitis (extremely rare)
     
  • The surgeon may fail to locate the Schlemm’s canal
     
  • The trabeculo-Descemet membrane is very fragile and may get perforated
     
  • Descemet membrane detachment which can occur even months after the procedure
     
  • Malignant glaucoma which occurs very rarely and is managed either surgically or medically

 

Aftercare & Recovery

The patient needs close monitoring and regular following for successful surgical outcomes. This will allow the ophthalmologist to promptly manage any complications that may arise.

Postoperatively, the surgeon prescribes medications such as high corticosteroid doses to reduce the risk of infection and inflammation. Untreated infection and inflammation can lead to scarring of the filtering bleb. The patient will take antibiotics six times daily for one to two weeks, then four times a day for the next two to four weeks. S/he will also take anti-inflammatory eye drops for two days only, at night. The patient will take NSAIDS two to three times daily for 15 days. 

On the day of the surgery and the following day, eye pressure is measured to exclude any complications like Seidel sign, hemorrhage, hypotony, etc. From the fourth to the eighth day, visual acuity and IOP are measured to detect and treat complications such as hyphema, choroidal detachment, endophthalmitis, etc. Subsequent follow-up visits will be on day 14, then at one month, three months, six months, nine months, one year and beyond, if necessary.

The patient must wear a transparent eye shield to protect the eye and avoid strenuous physical efforts. In case of a decrease in vision or pain, s/he should consult the ophthalmologist.
 

Outcome

DS is a safe surgical procedure to reduce IOP in various glaucoma surgeries with a lower complication rate. The use of an implant to maintain the intrascleral space improves the long-term results.