11. DISORDERS AND /OR ADVERSE REACTIONS - EYE- OCULAR SYSTEM - SUMMARY

Ref - other information

Contents

1.Evidence Based Medicine

2.Facts on Finger Tips                                                                                                          i.Acute Bacterial Conjunctivits                                                                                          ii. Viral Conjuctivitis                                                                                                            iii. Retinal Detachment                                                                                                        iv. Sjogrens Syndrome

3.Disorders and/or Adverse Reactions                                                                               Items  1 to 7

FACTS ON FINGER TIPS

 2. VIRAL CONJUNUNCTIVITIS

  Salient features

FACTS ON FINGER TIPS (MIMS)

 3. RETINAL DETACHMENT                                                   

     Salient Features

Definition    

 1.   Separation of neuroretina from underlying retinal pigment epithelium

Causes

1. Idiopathic
2. Idiopathic secondary to conditions such as myopia, melanoma, trauma, diabetes, or other cataract surgery

Clinical features

1. Painless loss of vision
2. Often described as being like a curtain falling over the eye
3. Flashing lights and sensation of spots before the eyes may be warning symptoms
4. Visual field defects
5. Loss of red retinal reflex on ophthalmoscopy

Management

1. Urgent hospital admission is indicated
2. Treatment aims to secure retina. Options include laser coagulation and pneumatic retinopexy

Key Points

1. Up to 50% patients may have warning symptoms
2. A sudden unilateral shower of flashing lights is a dangerous sign- if it occurs, the patient should be sent to specialist forthwith
3. Macular detachment may also take place, resulting in permanent loss of central vision

11. DISORDERS AND /OR ADVERSE REACTIONS - EYE -OCULAR SYSTEM - SUMMARY
  
( Ref- Harrisons - Priniciples of Internal Medicine Ninth Edition )

1. Lens Opacities (103)
2. Corneal edema ( 388 )
3. Cataracts ( 388 )
4. Glaucoma (102)
5. Diabetic Retinopathy (1750)
6. Ischemic optic neuropathy (104)
7. Myopia and presbyopia (102)

1. Lens Opacities (103)

Opacities form in diabetes mellitus and galactosemia ( sugar cataracts) from sustained high level of blood glucose and galactose, which is changed to sorbitol or dulcitol ( the accumulation of which leads to high osmotic gradient within lens fibers), in hypoparathyroidism which by lowering the concentration of calcium in the aqueous humor opacities newly forming lens fibers, after prolonged high doses of chlorpramazine and corticosteroid therapy, which are believed to result in lenticular opacities and in myotonic dystrophy , which is associated with a special type of cataract

Corneal opacities ( 388 )
   Adverse reaction - drug
    1. Vitamin D
    2. Mepacrine
    3. Chloroquine
    4. Indomethicin

2. Corneal edema ( 388 )
 
   Adverse reaction - drug
    1. Oral contraceptives

3. Cataracts ( 388 )
 
   Adverse reaction - drug
    1. Phenothiazines
    2. Corticosteroids
    3. Busulfan
    4. Chlorambucil

4. Glaucoma (102)

The common problem is one of high pressure due to impediment of the outflow of aqueous fluid. This is termed as glaucoma. In 90% of the caes (of the wide angle type) the cause is unknown, in 5% of the angle between the pupil is dilated, and in the remaining 5% the condition to secondary to some disease process that blocks outflow channel (inflammatory debris of uveitis , or red blood cells from hemorrhage in the anterior chamber ie hypema)

Glaucoma occurs in 2% of all patients over the age of 40, it may be aysymptomatic and go
unrecognized for years before it progresses rapidly to loss of vision. Therfore the intraocular
pressure should be measured routinely using a Schiotz tonometer.

Glaucoma  ( 388 )
   Adverse reaction - drug
    1. Mydriatics
    2. Sympathomimetics

5. Diabetic Retinopathy (1750)

Diabetic retinopathy is  or soon will be the leading cause of blindness in the United States.
On the other hand diabetics never become blind. Retinopathic lesions are divided into 2 large catogories , simple ( black background) and proliferative . The earliest sign of retinal change is an increased capillary permeability that is evidenced by leakage of dye into the vitrous humor after fluoresin injection.

Oclusion of retinal capillaries follows, which subsequent formation of saccular and fusiform
aneurysms. Arteroenous shunts also occur.

Retinopathy ( 388 )
   Adverse reaction - drug
     1. Chloroquine
     2. Phenothiazine

6. Ischemic optic neuropathy (104)

Ischemic optic neuropathy is another well recongnized entity. The onset is abrupt, usually in an elderly person. it may be painful. vision may be abolished completely, or there may an altitudinal or segmental defect in one eye. Examination of the fundus may show no abnormality, but later the optic disk may become pale, rarely there is congestion, hemorrhage, and swelling of the disk.

Optic neuritis ( 388 )
     Adverse reaction - drug
      1. Chloroquine
      2. Chloramphenicol
      3. Streptomycin     
      4. Isoniazid
      5. Ethambutol
      6. Quinine
      7. Phenothiazine
      8. Penicillamine
      9. PAS
      10. Phenylbutazone

7. Myopia and presbyopia (102)

The impairment of eyesight may be unilateral or bilateral , sudden or gradual, episodic or enduring. The common causes vary with age. in the late childhood and adolescence increasing difficulty in focusing the eyes and in sensing clearly usually can be traced to myopia, though an optic nerve disorder or supersellar tumor must be excluded.

In the middle age presbyopia is almost invariable and requires refraction and eye glasses. Still later in life cataracts, glaucoma, and retinal hemorrhages and detachments are the most frequent causes of visual disturbances.