Color vision test (Ishihara)

Have you ever wondered how we perceive colors and if everyone sees them the same way? Let’s learn one of the easy and commonly used colour vision tests, which is the “Ishihara Test”. The Ishihara colour vision test is a fascinating tool to screen the presence of red-green colour vision defects, it is based on … Read more

Optometry Quiz Series 1

Optometry Quiz

Welcome to the Optometry Quiz, where you can put your eye care knowledge to the test! Whether you’re a seasoned optometrist, a budding eye care professional, or just someone curious about the fascinating world of vision and eye health, this quiz is designed to challenge and educate you.

Vertical prism dissociation method

binocular balancing test

The procedure makes use of prisms to break the fusion between two eyes. The vertical prisms of the same amount are used to maintain equal degradation of image quality which is caused by prism. Don’t use horizontal prisms, as a compensatory positive and negative fusion vergence will make it difficult to break fusion or very … Read more

Astigmatism Clock dial test

Astigmatism Clock dial test

It consists of a series of the number of lines of equal length from the center and pointing towards a number similar to the face of a clock. Gaps between two numbers are equal to 30 degrees. Before reading procedure read optics behind Astigmatism clock dial test  Astigmatism clock dial test Procedure: Vision with COLC … Read more


How to perform keratometer

The keratometer is a specialized instrument used by optometrists and ophthalmologists to measure the curvature of the cornea. This measurement is important because it helps optometrists/ophthalmologists diagnose and manage a variety of eye conditions, such as astigmatism and keratoconus. In this blog post, we will discuss what a keratometer is, how it works, and why … Read more


A lensometer is an optical instrument that is used to determine the refractive power and the prescription of eyeglasses or contact lenses. It is a crucial tool in the field of optometry. Mainly used for measuring the back vertex power and front vertex power Two types of lensometer are available Manual lensometer The lensometer working … Read more


Retinoscopy is an optical diagnostic test used by eye care professionals to determine the refractive error of a patient’s eyes. It is a quick and accurate method of measuring the amount of correction required to produce a clear vision. The test is performed using a device called a retinoscope, which is an instrument that shines … Read more

Jackson Cross Cylinder

Introduction of JCC Jackson crossed cylinder is a combination of two cylinders of equal strength but of an opposite sign placed with their axis at 90 degrees to each other and mounted in a handle. Also known as the flip cross technique Principle of Jackson cross cylinder When light rays passed through an optical system … Read more

Duochrome test principle

Duochorme Test Principle

Duochrome test is a manual procedure that is performed as part of the subjective refraction process. Duochrome test is performed using a distance visual acuity chart with black letters, and the chart is split equally into two identical halves. Left side of chart have letter on a red background and right side of chart have … Read more

Optometry Spotters

Optometry picture quiz

Q1. Hint: Patient is wearing RGP contact lens from past 1 year and has complaint of burning sensation, itching and dry eyes.a. Identify the condition?b. How will you manage? Click below to show answer Show answer a) 3 and 9 o clock stainingb) Fit with Larger TD or Consider refitting with mini-scleral lens or Soft … Read more

Pink eyes

pink eye

Conjunctivitis, sometimes known as “pink eye,” is an infection- or allergy-related inflammation of the conjunctiva (a thin, clear membrane that covers the inside of the eyelid and the white part of the eye). The pink eye comes in a variety of forms, some of which are extremely infectious and transmit quickly from person to person … Read more


Binocular vision

BINOCULAR VISION AND SPACE PERCEPTION Slide 1 Slide 2 Relative subjective visual direction Slide 3-5 Retinomotor values Slide 6-7 Common relative subjective visual direction Slide 8-11 Retinal correspondence Slide 12 Horopter Slide 13 Panum’s fusional space/ area Slide 14 Fixation disparity Slide 15-17 Diplopia Slide 18 Retinal rivalry Slide 19 Suppression Slide 20 Monocular vision … Read more

The Krimsky test

Krimsky test

The Krimsky test is a widely accepted method of assessing the angle of deviation in strabismic patients. The Krimsky test is a modified version of Hirschberg’s Test, based on the well-established principle of Hering’s law of equal innervation. Krimsky test procedure In the Modified Krimsky Test, the patient fixates on a penlight, and prisms are … Read more

Bell retinoscopy

Bell retinoscopy

This procedure involves the use of a shiny steel ball, typically gold or silver in color, which is attached to a stick. The examiner holds the stick along the midline, at a certain distance from the patient. This technique derives its name from a small bell that used to hang on a string and served … Read more

Nott retinoscopy:

Nott retinoscopy

Nott retinoscopy is a technique similar to MEM (Monocular Estimated Method). In Nott retinoscopy, a fixation card (typically 6/6 in size) is positioned 40 cm away from the patient’s eyes. The card can be held by the patient or mounted on a measurement scale. The subject is instructed to view the target binocularly using their … Read more

Monocular estimation method

Monocular estimation method

MEM is a dynamic retinoscopy technique involves the use of a retinoscope with a series of cards attached to its head using magnets, such as the Welch Allyn retinoscope. These cards have a central aperture that helps the examiner align their viewing axis with the subject’s visual axis. The cards contain targets, such as printed … Read more

Types of retinoscopy

Types of retinoscopy

Static Retinoscopy In static retinoscopy, the patient is instructed to focus on a distant target positioned 6 meters away, which is considered to be at optical infinity. The reason for using 6 meters as the standard distance for retinoscopy is that when light rays come from a source situated 6 meters away, they are typically … Read more