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Fundamentals of Clinical Ophthalmology - part 2

Bác sĩ phẫu thuật có thể làm cho một đường rạch dày một phần, như đối với phẫu thuật extracapsular, và sau đó sử dụng điều này như là bước đầu tiên trong việc xây dựng một vết rạch hoặc tri-hoặc biplanar cho mảnh tay | TEACHING AND LEARNING PHACOEMULSIFICATION The surgeon can make a partial thickness incision as for extracapsular surgery and then use this as the first step in the construction of either a tri- or biplanar incision for the phaco hand piece. The nucleus is sculpted so that the surgeon can appreciate the difference between the plastic cataract and the human lens. Following initial grooving if the surgeon still feels confident that the cataract is within his or her ability then the nucleus can be rotated and further grooving performed. If difficulties are encountered then the phaco tip should be removed from the eye the incision opened and an extracapsular cataract extraction performed. Having sculpted three or four nuclei most surgeons will feel confident to continue with phacoemulsification and proceed to nuclear cracking with quadrant removal. The incision should always be constructed to enable the surgeon to perform an extracapsular extraction at any stage should this become necessary. Case selection Virtually all cataracts can be removed from the eye using phacoemulsification. The limiting factor is not the machinery but the surgeon s skill. It is important that the trainer and trainee select appropriate cases together at the preoperative assessment stage and arrange the theatre list accordingly. There are a number of points to consider when selecting cases Box 1.1 . The eye should have a clear healthy cornea a pupil that dilates well and a reasonable red reflex. A deep-set eye or prominent brow nose can make access difficult while learning. Axial length should be considered when selecting patients. Hypermetropic short eyes present problems with a shallow anterior chamber whereas myopic eyes have a deep anterior chamber. Patients with potential zonular fragility such as those with pseudoexfoliation or a history of previous ocular trauma should be avoided as should patients who will find it difficult to lie still for an appropriate length of Box 1.1 Case selection