Retinoscopy as a Screening Tool for Keratoconus

Abstract

Purpose: To investigate the validity and reliability of retinoscopy in screening for keratoconus using the rotating Pentacam Scheimpflug camera as the gold standard comparison. Methods: Patients between the ages of 10 and 30 years who were referred to the outpatient clinic with keratoconus, keratoconus suspect, reduced vision, eye discomfort or frequent change of glasses, or for refraction or refractive surgery, were screened by two independent and masked retinoscopists for the presence of scissoring reflex. Patients then underwent vision testing, slit lamp examination, and Pentacam imaging. A diagnosis of keratoconus by Pentacam was made if the final D index in the Belin and Ambrósio Display was ≥2.69. The results of retinoscopy and Pentacam examinations were compared to assess the validity and reliability of the test. Results: A total of 123 patients (67 male patients and 45 female patients) with a mean age of 21 years ±5.6 (range 10–30 years) comprising 245 eyes were included. There were 87 eyes with keratoconus, and using the Amsler–Krumeich classification, 67.8%, 26.4%, 2.3%, and 3.4% of the eyes had stage I, II, III, and IV, respectively. Sensitivity, specificity, positive predictive value, and negative predictive value of retinoscopy were 97.7%, 79.9%, 70.8%, and 98.4%, respectively. The area under the curve was 0.88 (95% confidence interval, 0.83–0.92). There was excellent agreement between the 2 retinoscopists (Cohen's kappa value 0.84). Conclusions: Retinoscopy appears to be a very sensitive and reliable test for detecting keratoconus including early disease. Such a test may be implemented in population-based screening programs for keratoconus.

The Scope of Optometry Practice in Jordan

“…24 Nevertheless, retinoscopy has been shown to be a successful tool for the screening of keratoconus by observing the scissoring reflex produced because of the irregular astigmatism caused by keratoconus. 25 Retinoscopy is taught in university programs in Jordan, and the students are extensively trained to master the use of the retinoscope as a means to attain the objective refraction of patients. It is recommended that further training on screening for keratoconus using a retinoscope is needed.…”

Towards Automating Retinoscopy for Refractive Error Diagnosis

“…On the other hand, retinoscopy has been shown to be very sensitive and reliable for detecting keratoconus even in the early stages of the disease [2,36]. In keratoconus eyes, the retinal reflex, instead of being evenly distributed and moving in a single direction, shows two edges that move towards each other.…”

“…However, screenings are difficult in developing countries due to a combination of factors, such as poor access to eye care services, unavailability of affordable solutions, and lack of awareness. The conditions are further exacerbated in low-income regions like Central Africa, where less than six trained eye specialists 2 are available for a million people [8]. Therefore, tools to enable refractive error screening in a low-cost and portable manner, without the need of skilled practitioners, can help in democratizing such mass screening programs.…”

“…For children, periodic vision screening using retinoscopy helps in detecting amblyopia risk factors, as amblyopia generally develops from birth up to age 7 years [60]. Moreover, retinoscopy is used to detect scissors reflex for diagnosing keratoconus [2], a serious corneal disease.…”

Keratoconus: current aspects of diagnosis and classification

“…К другим признакам относятся утолщение нервных волокон роговицы и симптом Ризутти или коническое отражение на лимбе с носовой стороны при освещении фонариком с височной [29]. Появление эффекта ножниц при ретиноскопии обусловлено движением теней в разных направлениях [30]. Биомикроскопия позволяет также установить патологический рефлекс размытой «нефтяной капли» в пределах предполагаемой вершины кератоконуса [31], кольцо Флейшера в виде отложения железа в эпителии вокруг основания конуса, стрии Фогта или складки десцеметовой мембраны.…”