Current and Emerging Therapeutic Strategies for the Treatment of Meibomian Gland Dysfunction (MGD).

Meibomian gland (MG) dysfunction (MGD) is a multifactorial, chronic condition of the eyelids, leading to eye irritation, inflammation and ocular surface disease. Initial conservative therapy often includes a combination of warm compresses in addition to baby shampoo or eyelid wipes. The practice of lid hygiene dates back to the 1950s, when selenium sulfide-based shampoo was first used to treat seborrhoeic dermatitis of the eyelids. Today, tear-free baby shampoo has replaced dandruff shampoo for MGD treatment and offers symptom relief in selected patients. However, many will not achieve significant improvement on this therapy alone; some may even develop an allergy to the added dyes and fragrances in these products. Other manual and mechanical techniques to treat MGD include MG expression and massage, MG probing and LipiFlow(®). While potentially effective in patients with moderate MGD, these procedures are more invasive and may be cost prohibitive. Pharmacological treatments are another course of action. Supplements rich in omega-3 fatty acids have been shown to improve both MGD and dry eye symptoms. Tea tree oil, specifically the terpenin-4-ol component, is especially effective in treating MGD associated with Demodex mites. Topical antibiotics, such as azithromycin, or systemic antibiotics, such as doxycycline or azithromycin, can improve MGD symptoms both by altering the ocular flora and through anti-inflammatory mechanisms. Addressing and treating concurrent ocular allergy is integral to symptom management. Topical N-acetylcysteine and topical cyclosporine can both be effective therapeutic adjuncts in patients with concurrent dry eye. A short course of topical steroid may be used in some severe cases, with monitoring for steroid-induced glaucoma and cataracts. While the standard method to treat MGD is simply warm compresses and baby shampoo, a more tailored approach to address the multiple aetiologies of the disease is suggested.

Retention rate of silicone punctal plugs placed by residents in a general clinic setting.

PURPOSE: To evaluate the retention rate of silicone punctal plugs placed in patients with dry eye in a general clinic setting by ophthalmology residents. METHODS: A cohort study reviewing charts of 88 patients who underwent punctal plug placement in the resident clinic at The New York Eye and Ear Infirmary from January 2007 to November 2008. Information recorded included age and sex of the patients, date of insertion, initial versus replacement plug, type and size of plug, location of insertion, and retention versus spontaneous extrusion versus removal of plugs at follow-up visits. Follow-up data were recorded at 30 and 60 days. RESULTS: Follow-up data for 106 plug placements were available at 30 days. A total of 71.7% were retained, 23.6% were lost, and 4.7% were removed. At 60 days, data were available for 96 plug placements. A total of 50.0% were retained, 47.9% were lost, 5.2% had been removed prior to 60 days, and 2.1% had been replaced prior to 60 days. CONCLUSION: Spontaneous extrusion is a common complication in punctal plug insertion, and the retention rate in a general clinic setting with ophthalmology residents is low. This may suggest that attention should be placed on improved instruction in placement techniques and sizing, better patient education on avoidance of rubbing, and importance of follow-up. It may also support the need for better designed plugs or considering alternatives to the silicone plugs, or the placement of such plugs in a dedicated punctal plug clinic under supervision of an experienced attending physician.

Effect of punctal plugs in patients with low refractive errors considering refractive surgery.

PURPOSE: To study the effect of punctal plug placement in patients undergoing refractive surgery for correction of poor vision. METHODS: A retrospective study was performed of 12 patients (21 eyes) who presented for initial refractive surgery or retreatment after LASIK or photorefractive keratectomy to improve visual acuity. Uncorrected visual acuity (UCVA) was documented in each eye. If tear normalization test was positive (indicating dry eye), silicone punctal plugs were placed in the lower lids of both eyes. Subjective patient UCVA and Snellen UCVA were assessed at 1 month. RESULTS: At 1 month, two eyes improved by three Snellen lines, nine eyes improved by two lines, seven eyes improved by one line, and three eyes remained unchanged. Uncorrected visual acuity was considered statistically significant (P < .0001) using the paired t test. No eye demonstrated decrease in visual acuity. One patient experienced punctal plug extrusion in both eyes. No other adverse outcomes were reported. One patient pursued additional refractive surgery after plug placement. No patient requested plug removal. CONCLUSIONS: Patients with low refractive errors note improvement in visual acuity after punctal plug placement.

Intraocular lens calculations after hyperopic refractive surgery.

PURPOSE: To evaluate the effect of hyperopic refractive surgery on intraocular lens (IOL) power calculation, compare published methods of IOL power calculation after refractive surgery, evaluate the effect of prerefractive surgery refractive error on IOL deviation, and introduce a new alternative formula for IOL calculation in patients who have had refractive surgery for hyperopia. DESIGN: Retrospective noncomparative case series. PARTICIPANTS: Twenty eyes from 13 patients who had undergone cataract surgery after previous hyperopic refractive surgery. METHODS: Seven different methods of IOL calculation were performed retrospectively: clinical history (IOL(hisK)), clinical history method at spectacle plane (IOL(hisKs)), vertex (IOL(vertex)), back calculated (IOL(BC)), calculation based on average keratometry (IOL(avgK)), calculation based on steepest keratometry (IOL(steepK)), and calculation based on the double K formula (IOL(doubleK)). Each method's result was compared with an exact IOL (IOL(exact)), which would have resulted in emmetropia. Each method was then compared with change in spherical equivalent induced by refractive surgery (SE(h)). A paired t test was used to determine statistical significance. MAIN OUTCOME MEASURE: Mean error in IOL power prediction for each method when compared to IOL(exact). RESULTS: When evaluating different methods of IOL calculations, IOL(vertex) was the most accurate, with a mean deviation from emmetropia of 0.42+/-1.75 diopters (D), followed by IOL(BC) (+0.54+/-1.86 D), IOL(hisK) (+1.56+/-2.35 D), IOL(hisKs) (+1.57+/-2.35 D), IOL(steepK) (+1.59+/-2.25 D), IOL(doubleK) (+1.65+/-2.56 D), and IOL(avgK) (+2.24+/-2.46 D). There was no statistical difference between IOL(vertex), IOL(BC), and IOL(exact). The power of IOL(avgK) would be inaccurate by 0.27x+1.53, where x = SE(h). Thus, most patients without the adjustment to IOL(avgK) would be left myopic. However, when IOL(avgK) is adjusted with this formula, there is no statistical difference to IOL(exact). CONCLUSIONS: For IOL power selection in previously hyperopic patients, a predictive formula based only on SE(h) and current average keratometry readings was not found to statistically differ from IOL(exact). The IOL(vertex) and IOL(BC), which also did not statistically differ from IOL(exact), require prerefractive surgery keratometry readings that are often not available to the cataract surgeon.

Effect of artificial tears on visual acuity.

PURPOSE: To study the effect of commonly used preservative free artificial tear, carboxymethylcellulose (CMC) 0.5% (Refresh Plus, Allergan, Irvine, California) on visual acuity in symptomatic dry eye (SDE) and asymptomatic dry eye (ADE) patients. DESIGN: Nonrandomized prospective clinical trial. METHODS: Prospective study involving 20 patients (40 eyes) with SDE and 20 patients (40 eyes) with ADE, all 40 years and older, were recruited from a clinic setting over a 1-month period. Distance visual acuity was measured by the Early Treatment of Diabetic Retinopathy Study (ETDRS) vision chart and near visual acuity was measured by the Lighthouse Near Vision chart before and 30 seconds after instillation of one drop of CMC. Distance and near visual acuity was measured both with and without correction. The duration of action of CMC was measured at 1-minute intervals until the patient's visual acuity returned to pretear level. RESULTS: In both SDE and ADE groups, uncorrected and corrected near and distance vision showed a statistically significant improvement after the use of CMC (P < .05). There was no statistically significant difference in improvement between the SDE and ADE groups in all categories (P values > .05). The mean duration of improvement of vision was 2.93 minutes in the SDE group and 3.70 minutes in the ADE group (P = .036). CONCLUSIONS: CMC 0.5% provides a temporary yet significant improvement in the visual acuity of SDE and ADE patients. The effect of artificial tears on visual acuity may be of diagnostic value in detecting ocular surface abnormality in symptomatic and asymptomatic patients.

Intraocular lens calculations after refractive surgery.

PURPOSE: To evaluate the effect of refractive surgery on intraocular lens (IOL) power calculation, compare methods of IOL power calculation after refractive surgery, evaluate the effect of pre-refractive surgery refractive error on IOL deviation, review the literature on determining IOL power after refractive surgery, and introduce a formula for IOL calculation for use after refractive surgery for myopia. SETTING: Laser & Corneal Surgery Associates and Center for Ocular Tear Film Disorders, New York, New York, USA. METHODS: This retrospective noncomparative case series comprised 21 patients who had uneventful cataract extraction and IOL implantation after previous uneventful myopic refractive surgery. Six methods of IOL calculation were used: clinical history (IOL(HisK)), clinical history at the spectacle plane (IOL(HisKs)), vertex (IOL(vertex)), back-calculated (IOL(BC)), calculation based on average keratometry (IOL(avgK)), and calculation based on flattest keratometry (IOL(flatK)). Each method result was compared to an "exact" IOL (IOL(exact)) that would have resulted in emmetropia and then compared to the pre-refractive surgery manifest refraction using linear regression. The paired t test was used to determine statistical significance. RESULTS: The IOL(HisKs) was the most accurate method for IOL calculations, with a mean deviation from emmetropia of -0.56 diopter +/-1.59 (D), followed by the IOL(BC) (+1.06 +/- 1.51 D), IOL(vertex) (+1.51 +/- 1.95 D), IOL(flatK) (-1.72 +/- 2.19 D), IOL(HisK) (-1.76 +/- 1.76 D), and IOL(avgK) (-2.32 +/- 2.36 D). There was no statistical difference between IOL(HisKs) and IOL(exact) in myopic eyes. The power of IOL(flatK) would be inaccurate by -(0.47x+0.85), where x is the pre-refractive surgery myopic SE (SEQ(m)). Thus, without adjusting IOL(flatK), most patients would be left hyperopic. However, when IOL(flatK) is adjusted with this formula, it would not be statistically different from IOL(exact). CONCLUSIONS: For IOL power selection in previously myopic patients, a predictive formula to calculate IOL power based only on the pre-refractive surgery SEQ(m) and current flattest keratometry readings was not statistically different from IOL(exact). The IOL(HisKs), which was also not statistically different from IOL(exact), requires pre-refractive surgery keratometry readings that are often not available to the cataract surgeon.

Advanced epithelial ingrowth 6 months after laser in situ keratomileusis.

Epithelial ingrowth is a common complication of laser in situ keratomileusis (LASIK). The cause is thought to be postoperative invasion of surface epithelial cells under the flap. We present a case of advanced epithelial cystic ingrowth that caused a profound reduction in visual acuity 6 months after a second LASIK enhancement.