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DREAM (Dry Eye - Amniotic Membrane) Study

"Treatment outcomes in the DRy Eye Amniotic Membrane (DREAM) study

Clinical Ophthalmology" 2018:12 677-681. PMID# 29670328

Dry eye disease (DED) is one of the most common ocular surface disorders in the USA and worldwide. It affects nearly 30% of the population, and its symptoms, such as ocular discomfort and visual fluctuations, represent the most frequent complaints in ophthalmic practice

Despite different underlying pathogenic processes, inflammation is a common denominator in DED, which in turn induces further damage to the corneal epithelium and its underlying structures

Cryopreserved amniotic membrane (CAM) was used to treat DED with ocular surface involvement, and its short-term efficacy was attributed to its known potent anti-inflammatory effect

CAM treatment significantly increased corneal nerve density which was correlated with improved corneal sensitivity and reduced dry eye symptoms

This treatment effect was seen for 3 months and may be attributed to CAM’s rich composition of neurotrophic factors, particularly nerve growth factor (NGF)

In this study, we retrospectively reviewed the effect of CAM in a larger patient population with moderate-to-severe dry eye. This study evaluates the efficacy of self-retained CAM (PROKERA® Slim, Bio-Tissue, Miami, FL, USA) in reducing signs and symptoms of DED associated with ocular surface involvement.

Inclusion criteria also included subjects aged 21 years and older who had moderate-to-severe DED, grades 2–4, as defined by the Report of the International Dry Eye WorkShop (DEWS): The ocular surface 2007;5(2):75-92 PMID: 17508116

A total of 97 eyes of 84 patients were included in this study. They exhibited severe dry eye (DEWS 3.25±0.5) despite maximal medical treatments such as artificial tears (82%), steroids (44%), cyclosporine-A (40%), antibiotics (30%), serum drops (8%), and nonsteroidal anti-inflammatory drugs (5%). Punctal plugs were also noted in 29 cases (35%)

The majority of patients presented with ocular discomfort (83%) and blurry vision (60%). Other symptoms included ocular pain (35%), redness (29%), and light sensitivity (14%)

Most of the cases manifested with superficial punctate keratitis (86%) followed by exposure keratitis (19%), filamentary keratitis (13%), epithelial defect (7%), and neurotrophic keratitis (2%)

Placement and removal of CAM were uneventful in all cases. Tape-tarsorrhaphy was used in 26 cases (31%) to alleviate discomfort at the time of insertion

The average duration of CAM placement was 5.4±2.8 days, range 2–11 days

CAM was removed from 4 eyes (4%) after 2 days due to CAM intolerance, and another CAM fell out of one eye after 2 days

Upon removal, the AM was intact (28%), partially dissolved (20%), totally dissolved (42%), or not stated (10%)

After removal, 74 patients (88%) demonstrated an improved ocular surface along with notable reduction of the severity of dry eye symptoms

The overall DEWS score was significantly reduced from 3.25±0.5 at the baseline to 1.44±0.6 at 1 week (p<0.001), 1.45±0.6 at 1 month (p<0.001), and 1.47±0.6 at 3 months (p<0.001). Specifically, ocular discomfort scores improved from 3.0±0.8 at baseline to 1.3±0.7 at 3 months (p<0.001); visual symptoms scores improved from 2.6±0.9 to 1.0±1.0 (p<0.001); corneal staining scores improved from 2.6±0.7 to 1.0±1.0 (p<0.001); and the overall corneal signs scores improved from 3.5±0.7 at baseline to 2.0±1.0 at 3 months (p<0.001). There was significant improvement in visual symptoms

This retrospective study demonstrates that self-retained CAM can accelerate the recovery of corneal surface health in patients with moderate and severe DED. Single placement of CAM for 5.4±2.8 days resulted in a significant improvement of DED signs and symptoms

This improvement was associated with restoration of corneal surface health as evidenced by resolution of corneal punctuate staining and improvement of visual symptoms. These findings are consistent with previous studies

The therapeutic effect of CAM in the treatment of DED can be attributed to multiple mechanisms of action. First, CAM acts as a therapeutic bandage that keeps the eye moist by retaining tears and protects the ocular surface from the surrounding environment. The second mechanism is by controlling ocular surface inflammation since it is well established that inflammation triggered by both innate and adaptive immune responses is critical to the pathogenesis and chronicity of DED. Taking the anti-inflammatory action as an example, CAM has been demonstrated to induce apoptosis of neutrophils, monocytes, and macrophages; reduce infiltration of neutrophils, macrophages, and lymphocytes; and promote polarization of M2 macrophages. Such anti-inflammatory action exerted by CAM is retained in the water-soluble extract and replicated by HC-HA/PTX3 purified from AM. A third mechanism is CAM’s ability to regenerate corneal nerves as previously reported, and this may explain the lasting effect. This notion is supported by the fact that NGF is abundantly present in CAM and is known to play an important role in nerve regeneration and epithelial healing

Other conventional topical anti-inflammatory therapies such as cyclosporine, corticosteroids, or non-steroidal anti-inflammatory drugs have been found to compromise corneal nerves and may explain why some cases do not respond

In this study, the ocular surface did not heal in 10% of cases following single placement of CAM and required repeat treatment. These cases had exposure keratopathy, neurotrophic conditions, or persistent epithelial defect. These results are comparable with what has been reported previously by Suri et al, who have published a recurrence rate of 14.3%. This recurrence may be explained by the nature of the underlying disease or associated comorbidities. In fact, 39% of the cases had associated blepharitis in this study, and the improvement of lid hygiene helped improve the dry eye symptoms. Therefore, it is essential to look for other comorbidities and treat them accordingly.

In conclusion, CAM is a promising treatment to enhance the recovery of ocular surface health and reduce signs and symptoms in patients with moderate-to-severe DED

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