Optimizing Suboptimal Results Following Cataract Surgery (eBook)

Refractive and Non-Refractive Management

Priya Narang, William B. Trattler (Autoren)

eBook Download: EPUB

2019 | 1. Auflage
Thieme Medical Publishers (Verlag)
9781638535690 (ISBN)

Infos

<p><strong><em>A concise review and comprehensive guide to improving cataract surgery outcomes</em></strong></p><p>Significant advances have been made in refractive surgery in the last decade. Eye surgeons today can leverage many cutting-edge intraocular lens (IOL) technologies such as multifocal, extended depth of field, toric, accommodating, and aspheric. Concurrent innovations including optics, phacoemulsification, superior keratometry and biometry, and posterior cornea evaluation have resulted in improved cataract surgery outcomes. Recent advances in the diagnosis and treatment of cataracts have dramatically improved patient satisfaction following cataract surgery, yet common and rare complications still occur such as dry eye, endophthalmitis, and retinal detachment. Furthermore, only 80% of cataract surgery procedures bring patients to within 0.5 diopters of their needed refraction.</p><p><cite>Optimizing Suboptimal Results Following Cataract Surgery: Refractive and Non-Refractive Management</cite> presents the latest techniques for achieving optimal results and overcoming complications in cataract surgery. Internationally renowned ophthalmic surgery pioneers Priya Narang and William Trattler have created an unparalleled guide to overcoming complex cases and residual refractive errors. The book starts with six chapters on suboptimal causes and considerations, followed by dedicated sections covering refractive and non-refractive enhancements. The fourth section features chapters on keratoconus, cystoid macular edema, endophthalmitis, toxic anterior segment syndrome, and vitritis, as well as intraoperative aberrometry, futuristic approaches and advancements, and telescopic IOLs.</p><p><strong>Key Highlights</strong><ul><li>Refractive enhancement procedures including corneal-based procedures such as astigmatic keratotomy, LASIK, PRK, and SMILE; IOL exchange; piggyback IOL; toric IOL; and premium IOLs and associated problems</li><li>Nonrefractive enhancement proced

Textauszug

1 Overview of the Causes of Suboptimal Outcomes Following Cataract Surgery: Role of Preoperative Screening and Adequate Counseling

Samir Narang and Priya Narang

Abstract

The causes of suboptimal outcomes following a cataract surgery can range from tear film abnormality to posterior segment disorder. Adequate preoperative screening and proper counseling help achieve an optimal result that eventually builds up the doctor–patient relationship to a satisfied and happy patient.

Keywords: preoperative screening, suboptimal outcomes, cataract screening, counseling, specular microscopy, informed consent

1.1 Overview of the Causes of Suboptimal Outcomes

There can be varied causes for suboptimal outcomes after cataract surgery that on a broad spectrum can range from the instability of tear film to corneal involvement and disorders, intraoperative inflammation, raised intraocular pressure (IOP) to vitreoretinal, and optic nerve involvement to a more serious condition such as endophthalmitis. On a lighter note, it can be an error of wrong intraocular lens (IOL) power calculation and insertion of a wrong IOL although the repercussions of this are quite serious as it leads to residual refractive error, and especially in the era of premium IOL surgeries, patients’ expectations are quite high and the surgeon has a constant challenge to meet these expectations. However, with the involvement of each layer or tissue of an eye in a detailed and multiple ways, the cause for suboptimal outcomes can be multiple. All the potential causes and preexisting ocular comorbidities should be diagnosed and evaluated, and the prospective outcomes should be discussed with the patient.

1.2 Preoperative Screening

Preoperative screening and examination although a routine is an essential prerequisite before surgical procedures that helps stratify risk, direct anesthetic choices, and guide the postoperative management. The preoperative screening is guided by the patient’s clinical history, comorbidities, and physical examination findings. This decision is multifactorial and involves consideration of visual status: individual patient’s vision requirements, patient motivation, ability of the eye to withstand surgical stresses, and the motivation or desire of the patient to proceed with a surgical option.

Although there is one treatment option for cataract, the complexity is multifold in a way from choosing the right IOL to the right IOL calculation formula, from preexisting retinal disorders to compromised endothelium, and from complexity of diagnostic tests to the risk of significant complications or comorbidities that may lead to suboptimal cataract surgery outcomes.

1.3 History Evaluation

1.3.1 Medical/Metabolic Illness

Proper medical history evaluation of the patient is essential, and leading questions from the surgeon asking for any systemic illness such as hypertension, diabetes ( Fig. 1.1), thyroid disorder, cardiac, or any other disorder for which the patient needs to take any medicine should be evaluated. In males above 50 years of age, leading question of any drug consumed for prostate enlargement should be asked for as it can lead to intraoperative floppy iris syndrome. Anticoagulants and blood-thinning agents should be stopped at least 3 to 4 days before the surgery is planned and can be resumed once the surgery is over.

Fig. 1.1 Fundus image of diabetic retinopathy.

Metabolic or genetic disorder history also carries a lot of weightage as it helps the surgeon to specifically look for the signs of the disorder. For example, for all cases of Marfan’s or Weil–Marchesani syndrome, the zonular integrity should be carefully assessed even though there is no major lenticular dislocation at the time of preoperative examination. This helps evade any unpleasant intraoperative surprise and apprises the surgeon of the correct ocular status.

History of any previous refractive or ocular surgery should also be evaluated. In case of history of refractive surgery, proper preoperative evaluation is again needed as to the calculation of the IOL power by applying appropriate IOL power calculation formulas after taking all the aspects into consideration. In cases with higher or asymmetric refractive errors in both the eyes, amblyopia should be ruled out and possible causes and outcomes should be evaluated.

Detailed history about the visual status of the patient few years ago can go miles in explaining the preoperative status of the eye.

History of previous retinal surgery or an intravitreal injection should draw a cataract surgeon’s attention to the aspect of performing a cataract surgery in previtrectomized eyes and the possibility of an increase incidence of intraoperative posterior capsular rupture.1,2,3,4,5,6,7 Previous intravitreal injections have the probability of damaging the posterior capsule and a preoperative B-scan or, if possible, an optical coherence tomography (OCT) examination to assess the integrity of the posterior capsule should be performed.

1.4 Vision

Recording visual acuity helps evaluate the functional visual capacity of the patient who is to undergo a surgery. The fall in vision should be correlated to the degree of cataract in the eye, and in case the functional vision loss exceeds the degree of cataract, other causes must be evaluated for the relevant fall of visual capacity.

1.5 Ocular Motility and Alignment Analysis

Squint analysis should always be performed and microtropia should always be assessed as it directs an underlying cause of amblyopia that may be present in a cataractous eye. Assessment of ocular motility should always be done to rule out any paralytic component. In addition to this, cover–uncover test, assessment of head posture, detection of cyclotorsion, or any associated nystagmus should also be performed.

1.6 Specular Microscopy and Pachymetry

Specular microscope ( Fig. 1.2a) helps detect corneal endotheliopathy ( Fig. 1.2b; Fig. 1.3) and forms an essential component of preoperative screening before a cataract surgery. A normal cataract surgery leads to 4 to 10% of the endothelial cell density (ECD) loss following surgery. This loss can be more in cases with preexisting endotheliopathies with less ECD count. Additionally, constant use of contact lens wear along with previous intraocular surgery also has a detrimental effect on the corneal endothelium. Assessment of all these corneal conditions helps determine a treatment plan for cases with diseased endothelium. Low ECD counts ( Fig. 1.3) with distorted ECD morphology invoke the application of endothelium-saving strategies that prevent further cell loss.

Patients with diseases such as glaucoma, iridocyclitis, or diabetes, or with history of previous ocular surgery are at increased risk of ECD loss and its adverse effects on cornea postsurgery ( Fig. 1.4). In accordance with specular microscopy, pachymetry should also be performed to assess the corneal thickness in eyes with compromised corneas.

1.7 Intraocular Lens Power Calculation and Intraocular Lens Choices

Essential preoperative testing includes keratometry readings, ultrasound axial length of the eye (A-scan), corneal topographic scanning, and a calculation of implant power requirements using a modern implant formula. Optional testing also might include potential visual acuity testing and ophthalmic photography.

Fig. 1.2 Specular microscopy images. (a) Specular microscope denoting the normal endothelial cell count, shape, and morphology. (b) Scattered guttata seen, suggesting possibility of development of early Fuch’s syndrome. (These images are provided courtesy of Dr. Ashish Nagpal, Retina Foundation, Ahmedabad, India.)

Fig. 1.3 Fuchs’ dystrophy. (a) Moderate Fuch’s dystrophy. (b) Advanced Fuch’s dystrophy with endotheliopathy. (These images are provided courtesy of Dr. Ashish Nagpal, Retina Foundation, Ahmedabad, India.)

Patients who have undergone a silicon oil implantation may give erroneous readings while performing IOL power calculation. All measures should be taken to counteract this error by employing the conversion factor during IOL power calculation. The conversion factor of 0.71 corrects for an apparent increase in axial length induced by silicon oil of viscosity 1,300 cSt.8

While implanting IOLs in such cases, silicon IOL should be deferred and a lens with 360-degree square edge with large optic diameter of 6 to 6.5 mm should be preferred as it gives greater viewing area for fundus examination.

1.8 Pupillary Reflexes and Posterior Segment Examination

Pupillary reflexes should be elicited in all the cases as it gives a correct idea of the status of the optic nerve and its pathway. This is especially important in hard and brunescent cataracts where it is difficult to evaluate the fundus due to increased density of the nucleus. A relative pupillary afferent defect in such circumstances indicates pathology in the posterior segment and a B-scan should be impertinently performed to rule out the anomaly.

The goal of preoperative fundus examination is to recognize any finding of clinical significance with regard to correct choice of the surgical procedure. Any finding of clinical significance is recorded on a fundus chart in all cases ( Fig. 1.5, Fig. 1.6, Fig. 1.7)....

Produkt-Details

• Erscheint lt. Verlag: 23.1.2019
• Sprache: englisch
• Themenwelt: Medizin / Pharmazie ► Medizinische Fachgebiete ► Augenheilkunde
• Themenwelt: Medizin / Pharmazie ► Medizinische Fachgebiete ► Chirurgie
• Schlagworte: Cataract Surgery • Complications in cataract surgery • intraocular lens • Ophthalmic Surgery • Optics • Phacoemulsification • Refractive Surgery
• ISBN-13: 9781638535690 / 9781638535690