Effective Use of Amniotic Membrane in Ocular Surface Disease

Fig. 18.1
Slit lamp photograph of the left eye from Case 1. There is near-complete madarosis, and on the ocular surface there is glue with an overlying clear disc, a faint outline of which can be seen temporally. The anterior chamber is deep centrally, as indicated by the posterior slit beam. There is ointment on the ocular surface. Not visualized in this image is a temporal suture tarsorrhaphy (see Fig. 18.2).


Fig. 18.2
External photograph of the left eye from Case 1. This once again demonstrates near-complete madarosis and in this image a suture tarsorrhaphy is noted temporally. After placement of amniotic membrane, followed by corneal gluing and a suture tarsorrhaphy, the ocular surface stabilized

Why Was a Dry Amniotic Membrane Graft Used in This Patient?

Amniotic membrane is harvested at the time of elective Cesarean delivery from consenting donors. The tissue can be freeze-dried by a commercial processor, after which it may be stored at room temperature in your clinic and applied directly to the ocular surface followed by the placement of a bandage contact lens. This is known as a dry (or dehydrated) amniotic membrane graft. An alternative method of processing involves immersion in glycerol and cryopreservation (the actual procedure is proprietary). This is known as a wet amniotic membrane graft and can come in several forms including as a flat sheet on a cardboard bed (e.g., AmnioGraft, manufactured by Biotissue, Doral, Florida) or attached to a ring (Prokera, Biotissue). In this patient we used a dry amniotic membrane graft largely due to ease of use (we have a supply stored at room temperature in our clinic) and ease of application (it can be handled and placed on the ocular surface relatively easily). The AmnioGraft should ideally be secured with either glue or sutures, and our patient was not an ideal candidate for ProKera due to significant eyelid scarring that may have prevented the device from staying in place.

Case 2

A 69-year-old female presented for annual follow-up of bilateral pterygia and Salzmann nodular degeneration. She noted that over the prior year her quality of vision had deteriorated, and she had been noticing occasional glare in bright lights. Her best-corrected visual acuity was 20/40 OD and 20/30 OS, with a decrease to 20/70 OD and 20/60 OS with brightness acuity testing. Slit lamp examination revealed a nasal and temporal pterygium with surrounding Salzmann changes OD, and a temporal pterygium and nasal Salzmann changes OS. She also had 2+ nuclear sclerosis OU. After an extensive discussion, the patient decided to proceed with pterygium excision and superficial keratectomy OD with both nasal and temporal amniotic membrane transplantation and with plans for cataract surgery in the future.

How Is Your Management of Pterygium or Salzmann Nodular Degeneration Affected by Lens Status?

In these cases, the lens status is an important consideration. If cataract surgery is in the near future, then ocular surface irregularities that may affect the corneal curvature (and, therefore, intraocular lens calculations) should be addressed first. In the case of pterygium, some studies have attempted to determine the predictability of its impact on K measurements and use this information for combined pterygium and cataract removal [15]. At this time, there appears to be less than optimal predictability based on available regression formulas, particularly for larger lesions. We take into consideration clinical examination findings, refraction, and corneal topography in determining whether a pterygium is visually significant and warrants excision prior to cataract surgery. The same principles apply for Salzmann nodular degeneration. Typically, we will obtain measurements for cataract surgery no sooner than 4–6 weeks after surgery for pterygium or Salzmann nodular degeneration.

If the patient does not have a visually significant cataract, then there may be more time to observe or pursue medical treatments, unless the patient is symptomatic or has disease that threatens involvement of the visual axis. For Salzmann nodular degeneration, any associated underlying conditions (e.g., blepharitis, ocular surface disease, interstitial keratitis) are treated aggressively, often with some form of local immunosuppression such as a topical steroid or cyclosporine. In patients with visual impairment and a lack of improvement with conservative treatments, surgical intervention is then recommended.

What Is Your Method of Choice for Surgical Excision of Pterygium? What About Salzmann Nodular Degeneration?

For pterygium excision, a conjunctival autograft is often a reasonable consideration, provided that the ocular surface is otherwise healthy and there are no signs of limbal stem cell deficiency. However, in the presence of ocular surface disease, conjunctival scarring or a double-headed pterygium, we prefer amniotic membrane transplantation over the area of excised conjunctiva. The graft may be secured in placed with fibrin glue, sutures, or both. We typically reserve the use of mitomycin C for recurrences or cases that are at high risk for recurrence (e.g., younger age). A recent study found that mitomycin C in conjunction with either AMT or conjunctival autograft resulted in a similar rate of success [16]. In the case of Salzmann nodular degeneration, the role of amniotic membrane is dependent on the extent of involvement; if a large superficial keratectomy is required, then an amniotic membrane graft over the area of excision can reduce the risk of recurrence while improving the rate of epithelial healing [17]. The patient should be made aware that the amniotic membrane graft will cause visual blurring if placed over the visual axis.

This patient had a visually significant cataract OD greater than OS, and therefore we recommended surgical intervention for the right eye. Intraoperatively, the nasal and temporal pterygia were excised and a superficial keratectomy was performed using a 57 blade and non-toothed forceps. A larger conjunctival excision was performed nasally than temporally, and eraser tip cautery was used to achieve hemostasis. The nasal and temporal amniotic membrane grafts were sequentially secured in place with fibrin glue as well as 9-0 vicryl sutures on the limbal side and 8-0 vicryl sutures on the conjunctival side. Postoperatively, the patient was treated with prednisolone acetate 1% and ofloxacin 0.3% drops, both QID. She initially noted foreign body sensation and photophobia with a drop in visual acuity to 20/500 on postoperative day one; however, these symptoms improved significantly over the first week with vision returning to baseline. The ocular surface was noted to heal well, and there was a small amount of residual anterior stromal scarring nasally ( Fig. 18.3 ).


Fig. 18.3
Slit lamp photograph of the right eye from Case 2, 1 month after nasal and temporal pterygium excision, superficial keratectomy for Salzmann nodular degeneration, and AMT. There was a faint residual anterior stromal scar noted nasally. There is a bandage contact lens in place

Why Did You Choose a Wet Amniotic Membrane Graft in This Patient?

In this particular case, there was both a nasal and temporal conjunctival excision as well as a superficial keratectomy performed. Given the location and extent of involvement, neither a dry amniotic membrane disc nor a ProKera would have provided adequate coverage. Therefore, we used two sheets of amniotic membrane (AmnioGraft) over the involved areas, which we secured in place with both glue and sutures. Although it requires more delicate handling than the other two products, the AmnioGraft can be cut to the appropriate size and shape based on anatomical considerations.

Case 3

The patient is a 60-year-old male who presents for follow-up of rosacea blepharitis. The patient notes that since his last visit 20 months ago the vision in his left eye has been decreasing. He also notes significant redness, irritation, and photophobia in both eyes. His uncorrected visual acuities on the day of follow-up are 20/200 OD and hand motion (HM) OS. Slit lamp examination demonstrates significant eyelid margin hyperemia and vascular telangiectasias, meibomian gland dysfunction, and 2+ conjunctival injection in both eyes. There is corneal pannus superiorly and inferiorly in both eyes. The right cornea has an area of mild stromal thinning temporally, while the left cornea has an area of severe thinning to less than 10% of normal stromal thickness with underlying endothelial pigment, suggesting a possible micro-perforation in the past. He also has 2+ nuclear sclerosis OD and 3+ nuclear sclerosis OS.

How Did You Arrive at the Diagnosis of Ocular Rosacea?

In this case, the diagnosis of ocular rosacea was straightforward. The patient had numerous facial telangiectasias, skin papules, rhinophyma, and the ocular findings described above (Fig. 18.4). The findings in ocular rosacea can range from only mild meibomian gland dysfunction and vascular telangiectasias at the eyelid margin to severe ocular surface disease with chronic conjunctival injection, symblepharon formation, corneal neovascularization, and corneal melt. The diagnosis may be challenging when facial skin changes are subtle or when ocular rosacea precedes extraocular changes; the symptoms of ocular rosacea (e.g., redness, irritation, foreign body sensation) are also relatively nonspecific [18]. Some patients with ocular rosacea have chronic blepharitis and ocular surface disease, whereas others have more of a relapsing remitting course. The differential diagnosis in severe cases includes graft versus host disease, atopic keratoconjunctivitis, ocular cicatricial pemphigoid, Stevens-Johnson syndrome, and chemical burn. In the absence of characteristic clinical features of rosacea, a thorough history and potentially a conjunctival biopsy may be indicated.
Jan 14, 2018 | Posted by in OPHTHALMOLOGY | Comments Off on Effective Use of Amniotic Membrane in Ocular Surface Disease

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