Noor Eye Training center - NETC

Acquired Myopia:
Acquired myopia can be divided into refractive and axial causes.
▪️Things that make the refractive power of the eye greater:
➖Lens nucleus or shape changes (increased curvature or increased refractive index):
¢ Cataract
¢ Diabetes
¢ ROP
¢ Lenticonus
➖Lens repositioning (increased effective lens power):
¢ Ciliary muscle shift:
© Toxemia of pregnancy
© Drugs (topiramate, chlorthalidone, sulfonamides, tetracycline, carbonic anhydrase inhibitors)
¢ Lens movement:
© Anterior lens dislocation
© Peripheral dislocation, bringing the relatively higher power of the lens periphery into the path of light
➖Ciliary muscle tone (increased lens curvature ):
¢ Antihistamines
¢ Miotics
¢ Excessive accommodation
¢ Improper refraction technique (inadequate fogging)
➖Corneal power increase (increased curvature)
¢ Keratoconus
▪️And things that make the eye longer:
➖Congenital or developmental glaucoma
➖Posterior staphyloma
➖Idiopathic progressive myopia
➖Scleral buckle

Meibomian Gland Dysfunction:
▪️Clinical features of MGD may be subtle to severe and often there is no correlation between symptoms and signs.
▪️The patients’ complaints are non-specific or include burning, redness, grittiness, watering and fluctuating vision.
▪️There is often discomfort after prolonged reading or working on computers.
▪️Thickening, hyperemia and irregularity of the posterior eyelid margin are common features of MGD.
▪️An early sign is pouting of the orifices, which are often capped with a solidified dome of oil.
▪️In health, the meibum is clear while in the diseased state, the consistency varies from cloudy to granular in the initial stages to a thick inspissated tooth-paste-like semisolid plug that is considered as hallmark of the disease.
▪️Another feature often noted is meibomian foam that results from the presence of soaps in the tear film.
▪️Clinical signs of the disease need to be differentiated from morphological changes brought about by age.
▪️The age-related signs are lid vascularity, hyperkeratinisation of the skin of the eyelids, lower lid telengiectasia, upper lid rounding, narrowing of orifices with pouting and decrease gland secretion.
▪️However, these changes are not associated with increased viscosity or opacification of the expressed lipid, which are markers for the disease.
▪️The meibomian glands are visualized through the tarsal conjunctiva on slit-lamp microscopy or with infrared photography (meibography).
▪️The features in meibography are gland dropouts, duct dilatation, hypotranslucent cysts and large hypertranslucent scars (chalazia).
▪️MGD is closely associated with keratoconjunctivitis sicca in 25-40% of cases and is the major cause of evaporative dry eye.
▪️Patients with meibomian gland dropout have been found to have a higher tear evaporation rate.
▪️Ocular discomfort, increased tear evaporation and epithelial changes as evidenced by fluorescein and Rose Bengal staining have been associated with gland dropout in obstructive MGD.
▪️Two other closely associated dermatological conditions are seborrheic dermatitis and rosacea.
▪️MGD is also associated with contact lens intolerance, giant papillary conjunctivitis, chalazia, floppy eyelid syndrome, recurrent corneal erosions and concretions.

The Pupil:
1- Rubeosis Iridis 2- Pseudoexfoliation
3- Iris Flocculus. 4- Posterior Synechiae