Ocular Hypotony Treatment & Management

Updated: May 06, 2016
  • Author: Sheila P Sanders, MD; Chief Editor: Hampton Roy, Sr, MD  more...
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Treatment

Medical Care

Hypotony is best managed by correcting the underlying problem. As a temporizing measure, the anterior chamber may be inflated with viscoelastic or a pars plana injection of viscoelastic or gas may be administered. No clinically useful medications are available that raise intraocular pressure (IOP) as a primary action. Studies of topical ibopamine showed a significant reduction of hypotony but a prohibitively high number of intolerant subjects. [9] Steroids may elevate IOP with prolonged use in individuals who are prone to a steroid response and may improve aqueous humor production by decreasing ciliary body inflammation. Increased fluid intake may slightly increase aqueous humor production.

With inflammatory conditions or with recent surgery or trauma, topical prednisolone acetate or difluprednate are the mainstays of therapy. Additional therapy, such as topical or systemic nonsteroidal anti-inflammatory agents (NSAIDs), systemic, sub-Tenon, or intravitreal steroids, or other systemic medications (eg, methotrexate, cyclosporin), may be appropriate. Because steroids can slow wound healing, use should be moderated in the case of wound leak or overfiltering bleb.

Aqueous humor suppressants can decrease flow through an overfiltering bleb or a wound leak long enough for healing to occur but can potentially worsen hypotony. The use of acetazolamide to accelerate absorption of suprachoroidal fluid is controversial.

Atropine and other cycloplegics deepen the anterior chamber, lessen iris-corneal touch, and restore normal anatomy of the lens-iris diaphragm and ciliary body. Pupillary dilation prevents a permanently small fixed pupil if synechiae form. Unfortunately, atropine also increases the uveoscleral outflow and can contribute to increased choroidal effusion, although its benefits usually outweigh its risks.

Cases of resolved bleb leaks with topical or systemic doxycycline, presumably through MMP-9 inhibition, have been reported. [10]

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Surgical Care

Wound leaks

Small wound leaks with a well-formed anterior chamber can be conservatively managed with patching or a large diameter bandage contact lens with prophylactic topical antibiotics.

Cyanoacrylate may be applied over a focal leak with a contact lens placed over the glue for comfort and stability.

Larger wound leaks that cause clinically significant hypotony or seem unlikely to spontaneously resolve are best managed with surgical revision.

Cyclodialysis cleft  [11]

Separation of the ciliary body from the scleral spur creates a large direct channel for uveoscleral outflow. Detachment of the ciliary body may, but does not necessarily, reduce aqueous humor production.

Cleft size does not bear directly on the degree of hypotony. The cleft may have been inadvertently created during ocular surgery or following trauma or intentionally created during a glaucoma operation.

A cyclodialysis cleft may be identified gonioscopically, by anterior segment imaging, or during exploratory surgery. Gonioscopy can be difficult on a soft globe.

Treatment options include argon laser photocoagulation, cryotherapy, external diathermy, ciliary body suturing, and vitrectomy with endotamponade. [12]

When the cleft closes, a dramatic rise in IOP can occur.

Clefts can spontaneously close.

Miotics should be avoided to prevent recurrence of cleft opening. After cleft closure, long-term cycloplegia may be indicated.

Retinal detachment

Rhegmatogenous retinal detachment is usually associated with mild hypotony. Occasionally, with large detachments, profound hypotony may develop.

The mechanism is believed to be the egress of aqueous humor through the vitreous, the retinal hole, and across the retinal pigment epithelium (RPE). Concurrent iridocyclitis may also reduce aqueous humor production.

Hypotony may slowly resolve following repair of the detachment because of lingering inflammation, or it may quickly reverse if, for example, a scleral buckle or silicone oil is used.

Overfiltering bleb or tube shunt, or posttraumatic hypotony

Acute

Mild transient hypotony following glaucoma surgery is common and usually well tolerated.

Observe and treat with liberal anti-inflammatory agents, cycloplegic agents, and reformation of the anterior chamber with viscoelastic, if needed. Viscoelastic injections may be repeatedly given.

Continue topical antibiotics for several days beyond the last chamber reformation procedure.

Anterior chamber shallowing becomes clinically significant if corneal-iris touch or corneal-lens touch results in development of synechiae or corneal decompensation.

Consider draining large choroidal effusions if no sign of improvement is present after several (7-14) days of medical and/or chamber reformation management, especially if retinal apposition is noted, the anterior chamber is markedly shallow, or the patient is at higher risk for hemorrhage. Hemorrhage risk factors include advanced age, history of glaucoma, history of vascular disease, and anticoagulated status. Even large choroidal effusions can resolve with conservative management, avoiding the need for further surgery.

Chronic

Surgical wound revision with resuturing of the scleral flap and/or conjunctival advancement or autograft is the procedure of choice for incompetent or overfiltering trabeculectomy. [13] Blood patch, laser application, cautery, cryotherapy, and trichloroacetic acid may work in some instances but are less effective. Conjunctival compression sutures work well to flatten a large bleb causing dysesthesia and can also help resolve hypotony. [14]

Conjunctival flaps alone can work well for diffusely incompetent blebs due to tissue thinning and avascularity.

Focal leaks may be treated with cyanoacrylate and a bandage lens, or temporary patching.

In a series of patients with chronic hypotony due to overfiltering blebs, 68% of cases resolved within 6 months of a subsequent cataract surgery. [15]

Eroded tube shunts can be particularly challenging to stabilize, and numerous graft alternatives, including cornea, dermis, and fascia lata, have been used with some success. [16] Care must be taken to remove any epithelial tissue that has grown in through the erosion. The position of the tube may need modification. In most cases of recurrent tube erosion, the device should be removed.

Laser trabecular sclerosis can be considered for severe, chronic hypotony if the cornea is adequately clear. [17] Long-term silicone oil fill is an option for those with cloudy corneas and can be combined with implantation of a keratoprosthesis. [18] Repeated intracameral injections of highly reticulated hyaluronic acid have provided stability in some cases. [19]

Uveitis

Anti-inflammatory agents are the mainstay of treatment. Peribulbar or intravitreal steroid injections have been used with some success, even in prephthisical eyes. Surgical removal of a cyclitic membrane may release tractional detachment of the ciliary body.

Vitrectomy and placement of silicone oil may be useful in refractory cases. [20]

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Consultations

Practitioners who have limited experience with hypotony should consider consultation with a glaucoma or retina subspecialist.

Consultation with a rheumatologist or internal medicine specialist is appropriate for difficult uveitic cases and for patients with uncontrolled systemic disorders.

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Diet

Patients at risk for hypotony should maintain good hydration.

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Activity

The patient should avoid lifting, bending, and strenuous activity. Sudden movement or straining could cause a vessel, which is already stretched by effusion in the suprachoroidal space, to bleed and create a suprachoroidal hemorrhage.

The patient should avoid any direct pressure on the eye that could cause further decompression. An eye shield, especially during sleep, is advisable.

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Complications

Any treatment for hypotony in a glaucoma patient with a trabeculectomy or tube shunt runs the risk of compromising the previous surgery to the point of raising the IOP above the target pressure, necessitating additional pressure-lowering treatment.

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