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Up Front | Apr 2008

Past and Present Refractive Techniques

A 4-week introduction to refractive surgery highlights popular procedures.

In the first course of the University of Ulster masters degree series on cataract and refractive surgery, registered participants learn a short history of refractive surgery that assists in understanding the trial and error process that has led to current advances. Steve Schallhorn, MD, former head of the US Naval Refractive Surgery Program, and Johnny Moore, FRCOphth, PhD, Consultant Ophthalmologist and Professor at the University of Ulster, present the first course lecture on the history of refractive surgery.

Antonio Leccisotti, MD, PhD, of Siena, and Arthur Cummings, MD, of Dublin, provide an overview of refractive surgery procedures. Sunil Shah, FRCOphth, FRCS(Ed), FBCLA, a Professor at Birmingham and the University of Ulster, discusses on the different excimer laser procedures. Although some information may be known, past experience has shown that few students are familiar with all available procedures.

Corneal and intraocular refractive techniques are overviewed, and practical cases are presented to enhance discussion between course tutors and students. This problem-solving approach directly links theoretical aspects with real-life situations. One example often involves presentation of a patient seeking refractive surgery. The scenario describes occupation, habits, personality, refraction, and anatomic features. Discussion of all surgical and nonsurgical options follows. It is interesting to observe that at the beginning of the discussion, each student proposing their own ideas, which evolve after interaction and debate with other students and tutors.

The first course has a slower pace than ensuing courses, allowing students to become familiar with the idea of Web-based learning, the platform used for course delivery, and Internet tools needed to complete the curriculum. It also allows students to get to know each other, which is important for complex ideas covered in future coursework.

WEEK 1
Students learn the earliest refractive techniques, such as those by Dutch physician Leendert Jan Lans, to the latest techniques, including corneal and intraocular techniques of the 21st century. Some lectures also discuss the value of incisional techniques, such as radial and astigmatic keratotomy in modern refractive surgery, as well as their use worldwide (Figure 1). Other topics include mini radial keratotomy and limbal relaxing incisions.

Views are also shared on why radial keratotmy has been progressively replaced by the excimer laser and where refractive surgery is heading in the next 10 years. Some students believe there will be developments and refinements, particularly intraocular refractive surgery developments, including accommodating IOLs due to the various disadvantages with current multifocal lenses, intracorneal lasers without the need for flap creation, and possible ways to prevent ametropia.

Jay Dermott, DOpt, of the United Kingdom, also delivers two lectures on the basics of refraction, refractive error, and how to successfully refract patients. Diagrams and figures help explain retinoscopy reflexes and ray diagrams. Complex refraction techniques for conditions such as keratoconus and the use of supplementary tests such as the duochrome are explained.

The main discussion emanating from these lectures was the use of cycloplegia in the prospective refractive surgery patient. Some favored tropicamide over cyclopentolate because of its shorter mode of action and no neurological side effects. Others argued that tropicamide provides less reliable cycloplegia and if not used, true cycloplegia was unknown. Target refractions and the use of contact lenses for prior adaptation trials were mentioned, especially in patients where the cycloplegic refraction is different to the dry refraction.

WEEK 2
Professor Leccisotti introduces the lecture with an overview of various corneal and intraocular surgeries and their indications (Figure 2). There is an accompanying MP3 audio file for download. Also in the second week, Mr. Dermott delivers two more lectures on (1) the principles of spectacle correction, introducing concepts such as ocular refraction, focal and far point, and how these terms relate to spectacle correction for ametropia, and (2) visual acuity measurement including discussions on the Snellen chart and fraction, minimum angle of resolution (MAR), and recognition acuity.

Debates started with comparison between the potential risks and complications of corneal and intraocular surgery. Many agreed that the exact risk of retinal detachment following refractive surgery was difficult to ascertain. The reported incidence of retinal detachment in myopes can range from 0.06% to 6% depending on risk factors such as the degree of myopia. Reported incidences following refractive surgery were compared to the group's anecdotal findings. Arevalo et al found the frequency of retinal detachment following LASIK to be 0.08%.1 The merits and drawbacks of treatment modalities for rhegmatogenous retinal detachment was also discussed. Other risks and complications of corneal and intraocular procedures were considered.

Treatment options for a presbyopic office clerk with a bilateral refraction of 3.50 D, such as LASIK (including monovision), multifocal IOLs, and accommodating IOLs, were discussed. A second case involving a 39-year-old taxi driver with high myopia was discussed also. The bulk of this discussion was based around the appropriate tests to perform to ascertain the best procedure. The final case discussed was a 21-year-old lawyer with high hyperopia and a shallow anterior chamber. Clear lens extraction and different types of IOLs available were discussed.

WEEK 3
Week 3 commences with Mr. Cummings' lecture on the rationale and indications for refractive surgery, providing an excellent resume of general options to treat any refractive patient, the base line investigations necessary for refractive surgery, and the limitations of different forms of refractive surgery (Figure 3).

A clinical case of a 30-year-old hyperopic secretary who had a discrepancy between her manifest and her cycloplegic refraction was presented. Consideration was given to whether the type of surgery, size of treatment, or other factors were more important in the causation of postoperative glare and haloes.

Students and tutors discussed whether it was more important to center a laser treatment on the visual or pupillary axis, and Colm McAlinden, BSc, an optometrist and refractive PhD student, provided a good summary on the definitions and relevance on optics, the pupillary axis, the optical zone, and the angle lambda.

Anatomical differences, the relevance of LASIK versus LASEK, and the value of retaining or discarding the epithelial flap post epi-LASIK or LASEK were also covered.

WEEK 4
Following a lecture by Johnny E. Moore, FRCOphth, PhD, students and tutors discussed the use of NSAIDs in uncomplicated intraocular surgery. Despite the adequate control that these drugs provide in postoperative inflammation without an increase in intraocular pressure, NSAIDs only inhibit the cyclo-oxygenase pathway whereas steroids also inhibit prostaglandin synthesis. Hence, the antiinflammatory activity of NSAIDs can be less pronounced. It was therefore recognized that optimum postoperative management after refractive surgery should include a short steroid course followed or associated with a longer NSAID administration.

Professor Shah presents a thorough review of excimer laser procedures, in which LASIK and the various surface ablation technique are compared in terms of safety, costs, pain, and short- and long-term refractive results. It was agreed that (at least in myopia) long-term results are comparable, but patient discomfort is the main drawback of surface ablation. The management of pain after surface ablation was also addressed. Topical and oral NSAIDs are the mainstay of treatment.

SUMMARY
Twenty-one students from England, Greece, Northern Ireland, Republic of Ireland, Scotland, South Africa, United Arab Emirates, United States, Wales, and the West Indies registered and successfully completed the 4-week course during February 2008. Each week, a 12-question, multiple-choice examination was completed online. Seventeen students were ophthalmologists ranging from consultant ophthalmologists and specialist registrars to junior ophthalmologists. The student cohort also consisted of two nurse practitioners with extensive refractive surgery experience and two optometrists. Regardless of the level of knowledge, understanding and experience at entry, all students expressed satisfaction in the amount of learning acquired.

Antonio Leccisotti, MD, PhD, is a Visiting Professor at the School of Biomedical Sciences, University of Ulster, Coleraine, Northern Ireland, and Director of the Ophthalmic Department, Générale-de-Santé Toscana, Siena, Italy. Dr. Leccisotti states that he has no financial interest in the products or companies mentioned. He may be reached at tel: +39 335 8118324†; fax: +39 0577 578600†; or leccisotti@libero.it.

Colm McAlinden, BSc(Hons), MCOptom, is an optometrist and refractive surgery PhD Student, School of Biomedical Sciences, University of Ulster, Coleraine, Northern Ireland. Mr. McAlinden may be reached at colm.mcalinden@gmail.com.

Damien McConville, MSc, MBCS, FHEA, is a Learning Technologist at the Institute of Lifelong Learning, University of Ulster. Dr. McConville states that he has no financial interest in the products or companies mentioned. He may be reached at +44 0 2890368537l; d.mcconville@ulster.ac.uk.

Johnny E. Moore, FRCOphth, PhD, is a Visiting Professor at the School of Biomedical Sciences, University of Ulster, Coleraine, Northern Ireland, and Department of Ophthalmology, Mater Hospital, Belfast Hospital Trust Northern Ireland, and Director of Leeson Eye Institute, Dublin, Ireland. Dr. Moore states that he has no financial interest in the products or companies mentioned. He may be reached at +353 0 16674778; johnnymoorebal@gmail.com.

Tara Moore, PhD, NTF, is a Course Director and Senior Lecturer at the School of Biomedical Sciences, University of Ulster, Coleraine, Northern Ireland. Dr. Moore states that she has no financial interest in the products or companies mentioned. She may be contacted at Tel: +44 0 7793226873; t.moore@ulster.ac.uk.

Sunil Shah, FRCOphth, FRCSEd, FBCLA, is a Visiting Professor at the School of Biomedical Sciences, University of Ulster, Coleraine, UK, Visiting Professor at the School of Life & Health Sciences, Aston University, Birmingham, UK, Medical Director, Midland Eye Institute, Solihull, UK, Consultant Ophthalmic Surgeon, Heart of England Foundation Trust, Birmingham, UK, and Consultant Ophthalmic Surgeon, Birmingham & Midland Eye Centre, Birmingham, UK. Dr. Shah states that he has no financial interest in the products or companies mentioned. He may be reached at tel: +441217112020; fax: +441217114040; or sunilshah@doctors.net.uk.

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