The Wills Eye Handbook of Ocular Genetics, 1st Edition

Levin AV, Zanolli M, Capasso JE (eds.) Essential Mednotes–The Wills Eye Handbook of Ocular Genetics, 1st Edition. New York: Thieme; 2017 (308 pp). ISBN 9781626232938 (Print).

Genetic eye disease represents an important cause of visual impairment. However, the relative rarity of the associated ocular phenotypes makes it challenging for healthcare professionals to accrue enough experience to develop an effective and efficient diagnostic approach. Fortunately, the authors and editors of the Wills Eye Handbook of Ocular Genetics have undertaken the worthy task of addressing this prevalent problem. It draws upon the collective expertise established at the Wills Eye Hospital. The stated objective for developing this handbook was to “provide a basic, yet detailed, reference for a variety of ocular genetic conditions.”

The Wills Eye Handbook of Ocular Genetics is a 308-page reference organized into 33 chapters. The first four chapters address fundamental genetic concepts that provide the framework for a practical approach to the diagnosis of ocular genetic conditions. This includes a forward-thinking discussion of potential ethical issues. Each of the remaining 29 chapters addresses a specific ocular anomaly, syndrome, or set of syndromes with a recognizable pattern of distinctive findings. This includes discussions of specific ocular phenotypes associated with pathogenic variation of multiple genes (e.g., Stickler Syndrome), and of multiple ocular phenotypes associated with pathogenic variation of a specific gene (e.g., ABCA4). The chapters are both logically and consistently organized. Each one begins with an abstract of its contents and key points to consider. The practical diagnostic approach defined in each chapter is supplemented by an efficient and effective discussion of pertinent genetic concepts, clinical pearls, and common pitfalls. Additionally, a set of questions and answers are provided so that the readers may test their knowledge acquisition.

The handbook's weaknesses are few. For future editions, its utilization of outdated nomenclature (e.g., mutation instead of pathogenic variant) should be remedied which is true for most textbooks. Similarly, a few genetic concepts have become outdated by the time of its publication. For example, karyotype is no longer considered the standard-of-care for the initial evaluation of patient with a potential genetic condition. Instead, SNP-based chromosomal microarray analysis is now recommended in the absence of specific concern for aneuploidy or rearrangement.

The handbook's strengths are many. First and foremost, the overall organization and that of individual chapters is well-executed and consistent. Additionally, it remains principally practical without neglecting the complexities that are important to consider, including the discussion of family pedigree and more advanced concepts with potential implications for clinical practice (e.g., the influence of heteroplasmy on ocular genetic conditions with mitochondrial inheritance patterns). The typical and atypical presentations of genetic eye diseases are detailed, as are the ocular and nonocular features of these conditions (e.g., the slit-lamp findings of ectopia lentis but also the wrist and thumb signs of Marfan Syndrome). This typically includes high-quality images and well-formatted tables containing practical points (e.g., the stages of Best Vitelliform Macular Dystrophy and their anticipated associated findings). There is a valuable discussion of the genetic and nongenetic differential and the important features to consider to distinguish between the diagnostic possibilities.

The Wills Eye Handbook of Ocular Genetics is a valuable resource for healthcare professionals involved in the evaluation and management of patients with ocular genetic conditions. It is a well-organized resource that represents the combination of clinical experience and the evidence-base. Although it cannot replace the expertise gained through ophthalmic and genetic training, the Willis Eye Handbook of Ocular Genetics is an admirable resource that provides a practical framework for the assessment of genetic eye conditions.