Download MBBS (Bachelor of Medicine, Bachelor of Surgery) Ophthalmology PPT 30 Diseases Of The Cornea 4 Lecture Notes
DISEASES OF THE CORNEA
Department of Ophthalmology
Xerophthalmia
n Deficiency of vitamin A(dietary def. or
defective absorption)
n Young malnourished children often in the
1st year of life
n Usually bilateral
n Absence of inflammation
n Precipitated by acute systemic illness
Xerophthalmia
n XN night blindness
n X1A conj. Xerosis
n X1B Bitots spots
n X2 Corneal xerosis
n X3A Keratomalacia<1/3
n X3B Keratomalacia>1/3
n XS Corneal scarring
n XF Xerophthalmia fundus
Bitot's spots (X 1B)
Corneal xerosis(X2)
Keratomalacia (X3B)
Treatment of xerophthalmia/ keratomalacia
n Local ocular therapy
n Vitamin A therapy - XN X3B
> 1 year 200,000 IU orally/100,000 IM
on day 0, 1, 2 weeks later
6-12 months or < 8kg half the dose
<6 mths 50,000 IU
Treatment of underlying condition
Prophylaxis against xerophthalmia
WHO recommendations
6-12 mths/ < 8kg 100,000 IU orally 3-6
monthly
>1yr <6yrs 200,000 IU orally 6
monthly
Lactating mothers 20,000 IU orally at
delivery
WHAT IS AN EYE DONATION
n It is donation of transparent
glass (Cornea) from donor to
recipient having Corneal opacity
with normal posterior segment
Magnitude Of The Problem in India
n 20% of blind population of the world
n 15 million total blind in India
n 6-7 million are corneal blind
n 1 million bilateral blind
(90% below age 45 yrs including 60% children
below 12 yrs)
Magnitude of The Problem
n Required collection ? 2,00,000( 50% utilization)
n Current Collection 2017? 52960
EBAI- 2017 Stats for INDIA(Unpublished data)
Magnitude of the Problem in India
nRequired transplant ? 1,00,000 cornea
n Current transplants (2017) ? 25153
EBAI- 2017 Stats for INDIA(Unpublished data)
n We have achieved 0.25% of all deaths
- 25 donation / 10,000 deaths
n Target is 1% of total deaths
- 100 donation /10,000 deaths
With a goal of 100,000 transplants and utilization
of 50%
Causes of Corneal
Blindness
Corneal Infections
Vasculrized Corneas with
thinning
Sloughing Cornea with
Perforation
Vitamin A Deficiency
Traumatic Corneal Opacities
Chemical Burns
Corneal Dystrophies &
Degenerations
Congenital Corneal
Opacities
Surgical Trauma
Demand Vs supply of cornea
n 1 lakh Cornea needed per year
n 30-40,000 new Corneal blind are
added every year
n 50,000 eyes collected in India every
year
n 8-9 million death occur every year in
India
n To clear the backlog we need at
least 277,000 corneas
Eye Bank
n Is an organization which deals with
- Collection
- Storage
- Distribution
For the purpose of corneal grafting and
research
Functions of Eye Bank
n To promote eye donation
n Registration of pledger for eye
donation
n Collection and processing of eyes as
per Eye Bank standards
n To evaluate the quality of tissue
before use
n Preservation of Tissue
n Distribution of tissue
n Research activities
Assessment of Donor Cornea
Preparing a Corneo-Scleral
Button
Placing Donor Cornea in
MK Medium for Preservation
Keratoplasty
Types of keratoplasty
n Lamellar SALK
DALK
DSEK
DMEK
n Penetrating
optical
therapeutic
tectonic
n Rotational autografts
Removing diseased host corneal button
Donor corneal button
Placement of graft over the recepient eyeball
Corneal Graft in place
Refractive corneal surgeries
n Substraction procedures
- Photorefractive keratectomy (PRK):
eximer laser is used in the center optical
zone.
n Laser assisted in situ keratomileusis
(LASIK):
- 130-160micron flap is raised
- mid stromal tissue is ablated by eximer laser
n Clear lens extraction
n Addition procedures
- Epikeratoplasty ? corneal surface
- Intracorneal lenses ? corneal stroma
- Intracorneal rings ? peripheral cornea
- ICL ? Implantable collamer lens
- Piggy bag lens
Epikeratoplasty
Intra corneal lenses
Intracorneal lens for presbyopia
Intracorneal rings
ICL
Piggy bag IOL
n Relaxation procedures
- Radial Keratotomy - peripheral
corneal stroma (6D)
- Astigmatic keratatotomy ? peripheral
corneal stroma
Radial keratotomy
n Coagulation ? compression procedures
- Thermokeratoplasty : peripheral cornea
(4D of hyperopia)
- Compression sutures : peripheral cornea
Thermokeratoplasty
Myopia
n PRK ? 6D
n LASEK- Laser epithelial keratomileusis
n LASIK ? Laser in situ keratomileusis(8-12
D)
n Clear lens extraction
n Phakic posterior chamber contact lenses-
ICL(Implantable Collamer surgery) - -3 to -
15D
Hypermetropia
n PRK
n LASEK
n LASIK ? 4D
n Conductive keratoplasty(CK)
n Intracorneal inlays
n ICL
Astigmatism
n Limbal relaxing incisions
n PRK ? 3D
n LASEK- 3D
n LASIK- 5D
n TORIC IOL
n Conductive keratoplasty- 3D
Presbyopia
n IOL- multifocal, bifocal or accomodating
n LASER induced monovision
n LASIK- corneal multifocality
n Intracorneal inlays
This post was last modified on 07 April 2022