Ibn al-Haitham, also known as Alhazen, was an 11th century Iraqi scientist who is considered the father of modern optics. He developed the scientific method and conducted experiments to test hypotheses. In his influential Book of Optics, he established optics as a scientific discipline and correctly explained the process of vision, rejecting previous emission and intromission theories. He also described the camera obscura and built the first pinhole camera. His work formed the basis of modern optics and influenced the development of eyeglasses, cameras, and other optical technologies.

2. Ibnal-Haitham,Fatherof Optics:
AnOptician, Optometristand
Ophthalmologist
Name :M.Danial, Fawad, Shaleem aijaz, kenneth David, Hamza qaisar , Danish
Semester :1st Semester fall-2019
Department :Mechanical (Eve)
Submitted to :Muhammad Osama
Subject :Islamiat

3. Anyone who hasever
used vision glassesor
contact lenses, taken
a picture with a
camera or watched
television has a
reason to bethankful
to the Father of
Optics,
Ibn-al-Haitham

4. Ibn al Haitham
Known in the West as Alhazen, Alhacen, or Alhazeni, Ibn al-Haitham
was the first person to test hypotheses with verifiable experiments,
developing the scientific method more than 200 years before
Europeanscholars learned of it—by reading hisbooks.
Ibn al-Haitham is regarded as the “father of modern optics” for his
influential Book of Optics (Kitâb al-Manâzir ) and his extensive
contribution in the field of optics.
Ibn-al-Haitham known was born in 965 CE in Basra (Iraq); also known
as Al-Basri. He received his education in Basra and Baghdad and later
traveled to Egypt and Spain and died in 1040 possibly in Cairo, Egypt.
He was also one of the most eminent physicist’s who ever lived. Along
with that he is also famous Mathematician, andastronomer.

5. In his massive study of light and vision,
Kitâb al-Manâzir (Book of Optics ), Ibn
al-Haitham submitted every hypothesis
to a physical test or mathematical proof.
Besides the Book of Optics, Ibn al-
Haitham wrote several other treatises on
optics.
His Risala fil-Daw’ (Treatise on Light) is
a supplement to his Kitab al-Manazir
(Book of Optics). The text contained
further investigations on the properties of
luminance and its radiant dispersion
through various transparent and
translucent media.
He also carried out further examinations
into anatomy of the eye and illusions in
visual perception.

6. Ibn al-Haitham also gave the first clear description and correct analysis of the
camera obscura and pinhole camera and built the world's first camera
obscura.
While Aristotle, Theon of Alexandria(335-405), Al-Kindi(801-873) and
Chinese philosopher Mozi(470-391 B.C.) had earlier described the effects of
a single light passing through a pinhole, none of them suggested that,what is
being projected onto the screen is an image of everything on the other side of
the aperture.
Ibn al-Haitham was the first to demonstrate this with his lamp experiment
where several different light sources are arranged across a large area. He was
thus the first to successfully project an entire image from outdoors onto a
screen indoors with the camera obscura.

7. Two major theories on vision prevailed in classical antiquity.
The first theory, the emission theory, was supported by such
thinkers as Euclid(323-283 B.C.) and Ptolemy(90-168), who
believed that sight worked by the eye emitting rays of light.
The second theory, the intromission theory supported by
Aristotle(384-322 B.C.) and his followers, had physical forms
entering the eye from an object.
Ibn al-Haitham argued that the process of vision occurs
neither by rays emitted from the eye, nor through physical
forms entering it.
He instead developed a highly successful theory which explained
the process of vision as rays of light proceeding to the eye from
each point on an object, which he proved through the use of
experimentation.

8. Lens(c.984)
Ibn al-Haitham’s treatise establishedoptical science.
The earlier lenses were made of circular
pieces of rock crystal or semiprecious stone,
such as beryl and quartz, which were ground
and polished so that they produced a
magnified image when looked through. The
oldest known lens artifact was one made of
rock crystal dating from around 640 B.C.E.
and excavated in Nineveh, near the modern
city of Mosul, Iraq. The most common form
was circular and thicker in the middle than
around the edge, and having both its front
and back surfaces the same shape.
The modern convex lens developed from
the ancient Greek burning glass. Here a
spherical vase of water would be used to
concentrate the rays of the sun onto a small
area, which heated up. The heat was used to
ignite fires in temples or to cauterized wounds.

9. The Iraqi mathematician and optics engineer Ibn Sahl (c. 940-1000)
wrote the treatise On Burning Mirrors and Lenses (984) in which he set
out his understanding of how curved mirrors and lenses bend and focus
light, using what is now known as Snell’s law to calculate the shape of
lenses. But the Iraqi Ibn al Haitham (965-1039), also known as Alhazen,
is regarded as “the father of optics” for his treatise, the Book of Optics,
(1011-1021), in which he proved that rays of light travel in straight lines,
explained hoe the lens in the human eye forms an image on the retina,
and described experiments with a pin hole camera.
In the thirteen century convex lenses were used in spectacles to
correct farsightedness. The use of concave lenses, which disperse the
light as opposed to concentrating it, to correct for farsightedness, came
in the early fifteen century. DH
GLASS, TELESCOPE, MICROSCOPE, SPECTACLES,
BIFOLCALS, EYE TEST, SPECTROSCOPE, CONTACT LENSES.

10. Refractive Errors
Refractive errors often are the main reason a person seeks
the services of an optician ,optometrist or ophthalmologist.
But what does it really mean when we're told that our
vision is blurry because we have a refractive error?
We see the world around us because of the way our eyes
bend (refract) light. Refractive errors are optical
imperfections that prevent the eye from properly focusing
light, causing blurred vision. The primary refractive errors
are nearsightedness, farsightedness andastigmatism.
Refractive errors usually can
with eyeglasses or contact lenses, or
be "corrected"
they can be
permanently treated with LASIK and other vision correction
surgery (also called refractive surgery).

11. How Light Travels
Through the Eye
In order to see, we must have light. While we don't fully understand all the
different properties of light, we do have an idea of how light travels.
A light ray can be deflected, reflected, bent or absorbed, depending on the
different substancesit encounters.
When light travels through water or a lens, for example, its path is bent or
refracted. Certain eye structures have refractive properties similar to water
or lenses and can bend light rays into a precise point of focus essential for
sharp vision.
Most refraction in the eye occurs when light rays travel through the curved,
clear front surface of the eye (cornea). Theeye's natural (crystalline) lens also
bends light rays. Even the eye's tear film and internal fluids (aqueous humor
and vitreous) have refractive abilities.

12. Howthe EyeSees
The process of vision begins when light rays that reflect off
objects and travel through the eye's optical system are refracted
and focused into a point of sharp focus.
For good vision, this focus point must be on the retina. The
retina is the tissue that lines the inside of the back of the eye,
where light-sensitive cells (photoreceptors) capture images in
much the same way that film in a camera does when exposed to
light. These images then are transmitted through the eye's optic
nerve to the brain for interpretation.
Just as a camera's aperture (called the diaphragm) is used to
adjust the amount of light needed to expose film in just the right
way, the eye's pupil widens or constricts to control the amount of
light that reaches the retina.
In dark conditions, the pupil widens. In bright conditions, the
pupil constricts.

13. Causesof RefractiveErrors
The eye's ability to refract or focus light sharply on the retina primarily is based on
three eye anatomy features: 1) the overall length of the eye, 2) the curvature of the
cornea and 3) the curvature of the lens inside the eye.
•Eye length. If the eye is too long, light is focused before it reaches the retina,
causing nearsightedness. If the eye is too short, light is not focused by the time it
reaches the retina. This causes farsightedness or hyperopia.
•Curvature of the cornea. If the cornea is not perfectly spherical, then the image
is refracted or focused irregularly to create a condition called astigmatism. A
person can be nearsighted or farsighted with or without astigmatism.
•Curvature of the lens. If the lens is too steeply curved in relation to the length of
the eye and the curvature of the cornea, this causes nearsightedness. If the lens is
too flat, the result is farsightedness.
More obscure vision errors, known as higher-order aberrations, also are related to
flaws in the way light rays are refracted as they travel through the eye's optical
system.
These types of vision errors, which can create problems such as poor contrast
sensitivity, are detected through new technology known as wave front analysis.

14. Detection and Treatment of
Refractive Errors
Your eye doctor determines the type and degree of
refractive error you have by performing a test called a
refraction.
This can be done with a computerized instrument
(automated refraction) or with a mechanical instrument
called a phoropter that allows your eye doctor to show you
one lens at atime (manualrefraction).
Often, an automated refraction will be performed by a
member of the doctor's staff, and then the eye care
practitioner will refine and verify the results with a manual
refraction.
Your refraction may reveal that you have more thanone
type of refractiveerror.

15. For example, your blurred vision may be
due to both nearsighted andastigmatism.
Your eye doctor will usethe results of your
refraction to determine your eyeglasses
prescription. A refraction, however, does
not provide sufficient information to write
a contact lens prescription, which requires
acontact lens fitting.
Eyeglass lenses and contact lenses are
fabricated with precise curves to refract
Light to the degree necessary to
compensate for refractive errors and bring
light to asharp focus on theretina.
Vision correction surgeries such as LASIK
aim to correct refractive errors by changing
the shape of the cornea, so that light rays
are bent into a more accurate point of
focus.
An eye care practitioner
performs amanual refraction.
(Image: National EyeInstitute)

16. Conclusion
Histheory of vision is basis
of all optical requirement
Thanks to Ibn alhaitham