EyeWorld Asia-Pacific September 2020 Issue

EWAP SEPTEMBER 2020 3 EDITORIAL Graham Barrett Chief Medical Editor EyeWorld Asia-Pacific EyeWorld Asia-Pacific • September 2020. Vol 16 No. 3 T he September issue of EyeWorld Asia- Pacific addresses the importance of the corneal surface in cataract and refractive surgery. The surface of the cornea is the most important refractive element and disruptions can have a major impact on outcomes. This is apparent in day to day assessments of patients for cataract surgery, where a poor tear film can lead to misinformation regarding the power of the cornea, particularly in relation to astigmatism. It is common practice to try and optimize the corneal surface prior to cataract surgery with lubricants and sometimes attention to the lid margin. For many surgeons, this is an integral part of their preoperative planning and is part of the routine work up for all patients. Personally, I use topography or tomography to determine whether reassessment after a period of lubricants and attention to the ocular surface is required. I also use the K calculator, which provides a mean vector for astigmatism to determine a more accurate representation of keratometry as different devices often disagree in their assessment of the magnitude and axis of astigmatism. Less frequently, we encounter pterygium, and the description of the surgical techniques from various authors in this issue is informative. Removal of the pterygium with conjunctival autograft has become the most favored technique to prevent recurrence, with mitomycin only being considered for those cases with recurrent pterygia. Amniotic membrane as an alternative to a conjunctival autograft has a place but mainly when insufficient conjunctiva is available. The presence of pterygia can also be a problem in assessing the power of the corneal surface. If the pterygium is small, it is not likely to impact biometry, but even a modest pterygium can lead to misleading keratometry and astigmatism. Depending on the age of the patient and their enthusiasm to be spectacle- free, pterygium surgery prior to cataract surgery may be preferable over proceeding with the pterygium in situ. In some instances, however, the patient may be unwilling to consider two procedures, and this is one of the rare circumstances where I would consider the refraction (prior to significant cataract) to assist with determining the astigmatism and whether a toric lens and what power of toric cylinder is required. Finally, the impact of medications on the ocular surface in the management of glaucoma can be a limiting factor. There is a wide range of responses to medications such as prostaglandin analogue but we are all familiar with the well-controlled glaucoma patients in whom injection and irritation become a major issue. Nonpreserved medications have a role in providing symptomatic relief and hopefully a new medication such as Rho kinase inhibitors, which are covered in the section on glaucoma, may prove to be an alternative that provides glaucoma control with less adverse effects on the ocular surface. It is interesting to reflect how important the ocular surface is and how its health and vitality impact on so many areas of our practice. EWAP Consider the ocular surface