CLINICAL: CORNEA

IDENTIFY AND TREAT THESE CONDITIONS BORN FROM PATIENT NON-COMPLIANCE

AS PRIMARY care providers, we must be prepared to diagnose and manage contact lens complications — something many practitioners, including myself, believe are on the rise, due to the advent of online sales. In fact, those who bought contact lenses at a doctor’s office more often complied to FDA contact lens recommendations (see http://bit.ly/2j3kg46 ) vs. those who purchased lenses online or through a retailer, reveals a study in Optometry. Roughly 19% of all contact lens purchases occur with online retailers, according to The Vision Council Internet Influence Report.

Here, I discuss the main complications associated with improper contact lens wear and care.

Bạn đang xem: CLINICAL: CORNEA

CONTACT LENS ACUTE RED EYE (CLARE)

CLARE is often associated with over-wearing or sleeping in contact lenses. Although the condition is possible with extended-wear RGP and silicone hydrogel (SiHy) lenses, it is more commonly associated with the over-wear of hydrogel lenses. Its etiology is poorly understood, but it has been linked, in the literature, with hypoxia, a gram-negative endotoxin response, lens debris and solution hypersensitivity. CLARE was once synonymous with “tight lens syndrome,” however, cases have also been documented in patients who have appropriately moving contact lenses.

Symptoms. Patients with CLARE will complain of sudden onset of unilateral pain, photophobia and redness, usually after sleeping in their contact lenses.

Signs. Slit lamp exam will show circumlimbal injection, limbal edema, focal or diffuse infiltrates in the mid-peripheral to peripheral cornea and, in more severe cases, a mild anterior chamber reaction. Little to no epithelial involvement is expected, so practitioners should be suspicious of microbial keratitis (MK) if an infiltrate with an overlying epithelial defect is noted.

As a brief, yet related, aside, CLARE can be mistaken for contact lens peripheral ulcers (CLPU), but CLARE is typically more painful, with diffuse redness, while CLPU will cause localized injection and milder discomfort.

Treatment. Treatment of CLARE is centered around immediate, yet temporary, discontinuation of contact lens wear. Topical steroids can be useful to reduce ocular inflammation. Cycloplegia for the first 24 hours, along with topical steroids, may be needed in patients who have an anterior chamber reaction. Consider conservative use of topical NSAIDs (days to a few weeks, with dosing appropriate for the chosen NSAID, to prevent NSAID-induced corneal melt) to aid in pain reduction. Some doctors recommend a broad-spectrum antibiotic or combination antibiotic/steroid drop for the first 24 to 48 hours, with daily follow-up until improvement is noted, as some symptoms and signs of CLARE overlap with MK.

When to resume contact lens wear. Once the acute symptoms and signs of CLARE resolve, which may take anywhere from several days to weeks, the patient can safely resume contact lens wear with a fresh lens.

However, in cases in which lens material (low Dk/hydrogel) or fit (tight fitting) may have contributed to the CLARE episode, refit the patient in a SiHy lens that has “good” movement.

Xem thêm : The Hidden Dangers: Acrylic Nails and Contact Dermatitis

In patients who have a history of lens abuse, consider prescribing a properly fitting daily disposable, along with strict instructions to refrain from napping or sleeping in their lenses. Patient re-education on lens care and compliance should follow any episode of CLARE.

INFILTRATIVE KERATITIS

Infiltrates can be seen in a variety of conditions not associated with contact lens wear. Contact lens patients who overwear their lenses or those who have poor hand and contact lens hygiene are more likely to present with CLPUs and MK, both of which are along the spectrum of infiltrative keratitis.

CLPU is an infiltrative keratitis that is thought to be caused by an inflammatory response to gram-positive bacteria, most notably, Staphylococcus aureas. These cases are not representative of an infection and, therefore, must be differentiated from true MK. Distinguishing a CLPU from MK can be difficult, as the early presentation of a CLPU has quite a bit of overlap with that of MK.

Here’s a brief review of how to differentiate the two, however, a thorough discussion of MK is beyond the scope of this article. (See http://bit.ly/2BrqQrT .)

CLPU vs. MK symptoms. Contact lens wearers with CLPU will present complaining of foreign body sensation, discomfort and redness. Suspicion for MK should be high when patients present with severe pain, light sensitivity and blurry vision.

CLPU vs. MK signs. CLPU presents with small (0.1mm to 1.5mm), round areas of focal infiltration with associated mild to moderate localized conjunctival injection. The infiltrates in CLPU are typically associated with an area of shallow overlying epithelial defect, without raised borders or an associated mucous plug. Mucopurulent discharge, epiphora and lid edema are mild or absent in CLPU, and anterior chamber reaction is rare. A slit lamp exam revealing lesions >2mm in size and further than 2mm from the limbus, especially those with raised or irregular borders and/or satellite infiltrates, should lead you to consider an infectious etiology. Also, mucopurulent discharge, lid edema, anterior chamber reaction, diffuse bulbar conjunctival injection, deeper (>20%) stromal infiltrate or any stromal thinning should also raise suspicion for MK.

Treatment. When suspicion for MK is very low, treatment involves discontinuing contact lens wear and prescribing a combination antibiotic/corticosteroid agent q.i.d. with daily follow-up to look for signs of infection. Others recommend a fourth-generation fluoroquinolone for the first day and adding a soft steroid or combination agent after infection is ruled out.

When to resume contact lens wear. Once CLPU resolves, patients may resume contact lens wear, but they should discontinue overnight wear. If the patient is in a planned replacement daily wear lens, he or she should switch to using hydrogen peroxide solution to enhance lens disinfection and should be counseled on hand hygiene to reduce the risk of MK. Refitting the patient in a daily disposable contact lens is also a great option for patients who have a history of poor contact lens hygiene.

CORNEAL NEOVASCULARIZATION

Corneal neovascularization may result from soft contact lens overwear, which creates a hypoxic state in the cornea. In this state, VEGF in the cornea is upregulated, and neovascularization occurs to improve oxygen supply. That said, corneal neovascularization can also happen secondary to chronic ocular surface inflammation, trauma and interstitial keratitis — causes that must be considered before treatment ensues.

Xem thêm : Flying with a CPAP Machine: Your Complete Guide for Air Travel

Symptoms. These patients are often asymptomatic, but may complain of reduced contact lens tolerance and shortened wear time, due to discomfort.

Signs. Blood vessel growth onto the cornea will be found during a thorough anterior segment slit lamp exam. However, you may miss it if you do not adjust the lids and patient’s gaze during the exam to ensure you have a view of the entire corneal surface.

Treatment. Treatment of corneal neovascularization secondary to contact lens overwear should be aimed at improving oxygen transmission to the cornea. To accomplish this, refit low Dk/t hydrogel wearers to higher Dk/t SiHy lens materials, and switch extended SiHy wearers to daily wear. In daily wearers, check for a tight-fitting lens, and refit the patient in a flatter base curve to allow for lens movement. In patients who have extensive corneal neovascularization or if you’re concerned about limbal stem cell deficiency (conjunctivalization, scarring and staining near the limbus), discontinue contact lens wear, and treat with a short course of topical corticosteroids or NSAIDs to reduce inflammation, in hopes of inhibiting angiogenesis.

When to resume contact lens wear. Judgement will be left to you, depending on the extent of the corneal neovascularization and when regression is seen.

GIANT PAPILLARY CONJUNCTIVITIS

GPC is hypersensitivy-related inflammation of the ocular tarsal palpebral conjunctivae. While its cause is likely multifactorial, mechanical irritation of the lid by the contact lens is a probable culprit. Although not a true allergic reaction to the contact lens or solution, GPC is more common during seasonal allergies and in patients with atopy. The condition worsens with increased contact lens depositing. Without routine examinations by the prescribing optometrist, a patient may be unaware he or she is placing him- or herself at risk for GPC due to heavily deposited lenses, particularly from wearing lenses beyond their replacement schedule or failing to remove lens deposits by rubbing his or her lenses during the care regimen. GPC may begin months to years after contact lens use is initiated, so patients may have difficulty correlating this delay in symptoms with their habitual contact lens regimen.

Symptoms. Contact lens patients may complain of itching or irritation after removing lenses, excessive movement of contact lenses, foreign body sensation and discomfort while wearing lenses, increased mucous production and blurry vision with wear.

Signs. GPC is diagnosed clinically during slit lamp exam, revealing the classic appearance of large papillae (<0.3mm) covering the tarsal conjunctiva of an everted upper lid. Milder cases may show smaller, focal papillae within hyperemic tarsal conjunctiva.

Treatment. Management of GPC should be aimed at reducing lens deposits and controlling inflammation. In mild GPC, prescribe improved lens cleaning and care and reduced daily wear time. Simply replacing the current deposited lens with a fresh lens may also help a wearer remain in lenses. In moderate to severe GPC, discontinuing lens wear for three to four weeks and then refitting in a daily lens may be your best bet to alleviating symptoms and preventing future occurrences. Topical corticosteroids can also hasten symptom and sign resolution. Some advocate for topical antihistamine use as well, especially if you are suspicious of underlying allergic conjunctivitis.

When to resume contact lens wear. See paragraph above.

KEEPING PATIENTS IN CONTACT LENSES

When it comes to the contact lens complications mentioned above, we must be able to identify and manage these quickly to ensure that our patients remain satisfied with their lens wear. OM

Nguồn: https://blogtinhoc.edu.vn
Danh mục: Info