Eyeworld

meibography summit: Better understanding of meibomian gland dysfunction and how to integrate meibography in diagnosis and treatment planning 4 | SUPPLEMENT TO EYEWORLD | SEPTEMBER 2019 pulsation treatment. 2 "We looked at the gland structure in pixelated detail using Adobe Photoshop, and it demon- strated that 69% of eyes that had thermal pulsation had an increase in visible gland struc- ture compared with untreated controls," she said. However, meibography is not essential, Dr. Yeu said. "Even looking at the lid margin beyond saponification and suds, if you see pitting, inspissated capping, or the lid margin notching, it is inevi- table that if you correlate it with the meibography, in the area of the notch, you will see a missing meibomian gland," Dr. Yeu said. "I have found that corneal topography is such a useful tool when I'm looking at the mires or finding an irregular pattern on a topography image preoperatively," said Marjan Farid, MD. Areas of irregu- larity and dropout, appearing as black or white areas, are correlated with patient reports of visual fluctuation. Signs of irregular astig- matism should also be noted. "There are red hot spots (of steepening) juxtaposed and mixed with flat islands," Dr. Yeu said. "Correlating the irregular area(s) on the axial map image with the Placido disc ring image is very telling." If clinicians only look for topographic axial map dropout, they will miss many MGD cases, Dr. Yeu contin- ued. "A lot of MGD patients have great Placido imaging because they do not neces- sarily have corneal staining, and with each blink, there is enough tear film coverage to capture the reflective image." However, a difference of more than 0.2 or 0.3 D on the average corneal power between two devices suggests evaporative disease with a very rapid tear breakup time, she said. When surgeons see dis- crepancies between devices, they need to explain this to patients, treat them, and ask them to return for repeat test- ing, said Sumit "Sam" Garg, MD. Béatrice Cochener-La- mard, MD, PhD, underscored the importance of being able to obtain quantitative values to grade MGD. "It is good to show patients their disease, but for me, the addition- al parameters that devices provide, like the thickness of the tear film and the quality of blinking, may be even more valuable than the gradient of the atrophy at that point," she said. "The combination of these parameters makes it possible to quantify the quality of the dynamics of the ocular surface. Characterizing the tear film by its thickness, its distribution, or the height of the tear meniscus is of great interest, especially since an excess of evaporation and a decrease in secretion are often combined and will require treatment addressing these two aspects of the deficit." An additional test, such as double-pass technolo- gy, demonstrates tear film instability and meibomian gland function. "By looking at point-spread function—imag- es over a 20-second period at 5-second intervals—instability of the tear film is graphically illustrated," Dr. Bowden said. In addition, Marguerite McDonald, MD, explained that keratography is useful in objectively measuring tear breakup time; there are systems available that accu- rately measure breakup time using real-time keratographic monitoring. Critical eyelid examination With this information in hand, the clinician proceeds with the clinical examination. "We need to educate all of our colleagues in optometry and ophthalmology of the impor- tance of looking at the eyelids and how you can diagnose MGD very simply by doing that," Dr. Donnenfeld said. All of the Summit partic- ipants strongly agreed that cli- nicians should perform eyelid examinations on all cataract patients. "Clinicians often focus on the cornea and the intra- ocular exam and may ignore the external examination," said Edward Holland, MD. "It is important to examine the eyelid position, eyelid function, and the blink rate. Then we evaluate the anterior and posterior lid margins and expressed meibum to see if there's anterior blepharitis or MGD." When expressing the meibomian glands, clinicians observe whether the meibum is clear, viscous, free-flow- ing, or thick and whether the glands are obstructed. They also examine the tear film and tear film meniscus height. Terry Kim, MD, instructs technicians in his practice to perform meibography on patients in whom he witnesses any abnormality upon manual expression of the lower eyelid margin with a cotton-tip applicator. On meibography, dilatation or truncation of the glands signifies MGD and obstruction that must be relieved, whereas atrophy indi- cates significant MGD. "Even if only a few glands display atrophy, my belief is that all of the glands are affected and you have MGD," he said. If patients do not have gland secretions, the gland orifices may be epithelialized, continued from page 3 Resources ASCRS Preoperative OSD Algorithm Starr CE, et al. An algorithm for the preoperative diagnosis and treatment of ocular surface disorders. J Cataract Refract Surg. 2019;45:669–684. www.jcrsjournal.org/article/S0886-3350(19)30242-1/ The International Workshop on Meibomian Gland Dysfunction Nichols KK, et al. The international workshop on meibomian gland dysfunction: executive summary. Invest Ophthalmol Vis Sci. 2011;52:1922–1929. iovs.arvojournals.org/Issues.aspx?issueID=932970#issueid=932970

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