DISEASE OF CRYSTALLINE LENS, CATARACTpptx

These occur due to some disturbance in the normal growth of the lens.
When the disturbance occurs before birth, the child is born with a congenital cataract.
Developmental cataract may occur from infant to adult.
Congenital and developmental opacities are very common (same appearance).
These are detected with the beam of slit lamp under full mydriasis.

1. DISEASE OF CRYSTALLINE LENS BY – MS. MEGHNA VERMA ASSISSTANT PROFESSOR DEPARTMENT OF OPTOMETRY RAMA UNIVERSITY

2. CONTENTS Congenital malformations Cataract –congenital, developmental, senile, traumatic, complicated and secondary cataract. Dislocation of lens Surgical procedure for removal of lens Intra ocular lens implantation

3. CONGENITAL ANOMALIES Coloboma of the lens Congenital ectopia lentis Lenticonus Congenital cataract Microspherophakia

4. COLOBOMA OF THE LENS It is seen as a notch in the lower quadrant of the equator. It is usually unilateral and hereditary.

5. CONGENITAL ECTOPIA LENTIS It is seen in lens displacement .

6. LENTICONUS It refers to cone-shaped elevation of the anterior pole ( lenticonus anterior or posterior pole ( lenticonus posterior) of the lens.

7. MICRO- SPHEROPHAKIA In this condition, the lens is spherical in shape (instead of normal biconvex) and small in size. It occur due to Marfan’s syndrome.

8. CATARACT Opacification of lens .

9. DISLOCATION OF LENS The lens is a transparent, biconvex structure placed between iris and the vitreous in a saucer shaped depression (patellar fossa ). Displacement of the lens from its normal position (in patellar fossa ) results from partial or complete rupture of the lens zonules . A dislocated lens may be present into the pupil or in the anterior chamber, the vitreous, sub-retinal space, partially or completely.

10. Clinical features of anterior dislocation There are shallow anterior chamber and presence of lens in the anterior chamber. Clear lens looks like an oil drop in the aqueous. Clinical features of posterior dislocation These include: deep anterior chamber, aphakia in pupillary area, and iridodonesis . Ophthalmoscopic examination - lens in the vitreous cavity.

11. Complications It is associated with dislocated lens are uveitis and secondary glaucoma. Management A dislocated lens from the vitreous cavity should be removed only if it is causing uveitis or glaucoma. From the vitreous cavity lens can be removed after total vitrectomy .

12. CATARACT The crystalline lens is a transparent structure. Its transparency may be disturbed due to degenerative process leading to opacification of lens fibers. Development of an opacity in the lens is known as cataract . LENS CAPSULE ANTERIOR EPITHELIUM LENS FIBRES [NUCLEUS & CORNTEX] SUSPENSORY LIGAMENTS OF LENS

13. CONGENITAL CATARACT These occur due to some disturbance in the normal growth of the lens. When the disturbance occurs before birth, the child is born with a congenital cataract . Developmental cataract may occur from infant to adult. Congenital and developmental opacities are very common (same appearance). These are detected with the beam of slit lamp under full mydriasis . A  cataract  is a cloudy area in the  lens of the eye that leads to a decrease in vision of the eye. [ 1] [7 ] Congenital cataract an result in amblyopia if not treated in a timely manner. [15]

14. ETIOLOGY Exact etiology is not known. Some factors which have been associated with certain types of cataracts: Heredity Due to an anomaly in the chromosomal pattern. About one-third of all congenital cataracts are hereditary. II . Maternal factors - Malnutrition during pregnancy. Maternal infections like rubella, associated with cataract. Reported who have taken certain drugs during pregnancy. Maternal exposure to radiation during pregnancy.

15. III . Featal or Infantile factors Deficiency of oxygen (anoxia) due to placental haemorrhage. Metabolic disorders Other congenital anomalies e.g. Lowe's syndrome, myotonia dystrophy. Birth trauma. Malnutrition in early infancy - cause developmental cataract. IV . Idiopathic. About 50 percent cases are unknown etiology .

16. MANAGEMENT OF CONGENITAL AND DEVELOPMENTAL CATARACT INVESTIGATIVE WORK UP 1 . Ocular examination 2. Laboratory investigations 3. Surgical procedures 4. Correction of paediatric aphakia

17. ACQUIRED CATARACT In congenital and developmental cataracts, occur due to disturbance in the formation of the lens fibres , i.e . opaque lens fibres are produced. While, in acquired cataract, opacification occurs due to degeneration of the already formed normal fibres . Any factors [physical , chemical or biological] Disturbs the intra and extracellular equilibrium of water and electrolytes. OR, De-arranges the colloid system within the lens fibres . At the end of result, opacification of lens.

18. SENILE CATARACT Also called as ‘ age-related cataract ’, most common type of acquired cataract affecting equally male & female, above the age of 50 years. At the age of 70 years, over 90% of the individuals develop senile cataract. The condition is usually bilateral, but almost always one eye is affected earlier than the other. Morphologically, the senile cataract occurs in two forms, the cortical (soft cataract) and the nuclear (hard cataract). The cortical senile cataract may start as cuneiform (more commonly) or cupuliform cataract.

19. ETIOLOGY The various factors implicated are as follows: Factors affecting age of onset, type and maturation of senile cataract Heredity, Ultraviolet radiation, Dietary factors, Dehydrational crisis (due to diarrhoea, cholera), Smoking. Causes of presenile cataract Heredity, Diabetes mellitus, Myotonic dystrophy & Atopic dermatitis is associated with posterior subcapsular type of presenile cataract.

20. C. Mechanism of loss of transparency In nuclear and cortical senile cataracts. Cortical senile cataract Decreased levels of proteins, amino acids & potassium → Increased sodium and hydration of the lens. End result, coagulation of proteins. The probable course of events leading to senile opacification of cortex . 2 . Nuclear senile cataract Age related nuclear sclerosis → dehydration and compaction of the nucleus resulting in a hard cataract .

21. STAGES OF MATURATION [A] Maturation of the cortical type of senile cataract Stage of lamellar separation In this stage, cortical fibers separated by fluid . It can be seen by slit-lamp examination only. Stage of incipient cataract In this stage, early detectable opacities between clear areas. Two distinct types of senile cortical cataracts - Cuneiform senile cortical cataract Cupuliform senile cortical cataract

22. 3 . Immature senile cataract (ISC) The cuneiform or cupuliform patterns can be recognized till the advanced stage of ISC when opacification becomes more diffuse and irregular. The lens appears greyish white but clear cortex and iris shadow is visible. At this stage, lens may become swollen due to continued hydration . This condition is called ‘ intumescent cataract ’. Due to swollen lens, anterior chamber becomes shallow . 4. Mature senile cataract (MSC) In this stage, opacification becomes complete, i.e., whole of the cortex is involved. Lens becomes pearly white in color. Such a cataract is also known as ‘ ripe cataract ’.

23. 5 . Hyper mature senile cataract (HMSC ) When the mature cataract is left , the stage of hyper maturity sets in. The hyper mature cataract may occur in any of the two forms: Morgagnian hyper mature cataract Sclerotic type hyper mature cataract Morgagnian hyper mature cataract : In some patients, after maturity the whole cortex liquefies and the lens is converted into a bag of milky fluid. The small brownish nucleus settles at the bottom , altering its position with change in the position of the head. Sometimes, calcium deposits may also be seen on the lens capsule .

24. (b) Sclerotic type hyper mature cataract : After the stage of maturity, the cortex becomes disintegrated and the lens becomes shrunken due to leakage of water . The anterior capsule is wrinkled and thickened due to proliferation of anterior cells and a dense white capsular cataract may be formed in the pupillary area. Due to shrinkage of lens , anterior chamber becomes deep and iris becomes tremulous ( iridodonesis ).

25. [B ] Maturation of nuclear senile cataract In it, the sclerotic process, the lens inelastic and hard , decreases its ability to accommodate and obstructs the light rays. These changes begin centrally and slowly spread peripherally up to the capsule when it becomes mature. The nucleus may become cloudy (greyish) or tinted (yellow to black) due to deposition of pigments. The nuclear cataracts are either amber, brown or black & rarely reddish in color .

26. CLINICAL FEATURES Symptoms Glare, Uniocular polyopia , Coloured halos, black spots in front of eyes, blurring, distortion & loss of vision . Signs Visual acuity testing - Depending upon the location and maturation of cataract, the visual acuity may range from 6/9 to just PL + . Oblique illumination examination - reveals color of the lens in pupillary area which varies in different types of cataracts. Test for iris shadow - When lens is completely transparent or completely opaque, no iris shadow is formed & presence of iris shadow is a sign of immature cataract.

27. On ophthalmoscopic examination - A reddish yellow fundus glow is observed in the absence of any opacity in the media. Partial cataractous lens shows black shadow against the red glow in the area of cataract. Complete cataractous lens does not even reveal red glow. Slit-lamp examination - reveals complete morphology of opacity (site, size, shape, color pattern and hardness of the nucleus). Colour and hardness of nucleus Grade I - Soft White or greenish yellow Grade II - Soft-medium Yellowish Grade III - Medium-hard Amber Grade IV - Hard Brownish Grade V - Ultrahard Blackish (rock-hard) COMPLICATIONS Phacoanaphylactic uveitis, Subluxation or dislocation of lens, Lens-induced glaucoma.

28. MANAGEMENT OF CATARACT IN ADULTS Treatment of cataract consists of its surgical removal. Some non-surgical measures may be of help till surgery is taken up . Wearing sunglasses and a wide brimmed hat, eating leafy vegetables and fruits, and avoiding smoking may reduce the risk of developing cataracts, or slow the process. [1] [10] Non-surgical treatment Treatment of cause of cataract. Measures to improve vision in the presence of incipient and immature cataract

29. B . Surgical management Visual improvement . This is the most common indication. Medical indications - may be advised cataract surgery due to Lens induced glaucoma, endophthalmitis and Retinal diseases like diabetic retinopathy or retinal detachment, treatment of which is being hampered by the presence of lens opacities. Cosmetic indication .

30. PREOPERATIVE EVALUATION Once it has been decided to operate for cataract, a thorough preoperative evaluation should be carried out. General medical examination Diabetes mellitus, hypertension and cardiac problems, lung disorders & urinary tract infection. Ocular examination Done by slit lamp examination by overview of an eyeball. Search for local source of infection ( conjunctival infections, meibomitis, blepharitis and lacrimal sac infection). Anterior segment evaluation - Presence of keratic precipitates at the back of cornea, in a case of complicated cataract, uveitis. Preoperative evaluation is incomplete without the measurement of IOP.

31. PREOPERATIVE MEDICATIONS AND PREPARATIONS Topical antibiotics such as tobramycin/gentamicin/ciprofloxacin QID for 3 days just before surgery is advisable against endophthalmitis. Preparation of the eye to be operated. Eyelashes of upper lid should be trimmed at night and the eye to be operated should be marked. An informed and detailed consent should be obtained. Each patient should be instructed to have a scrub bath including face and hair wash with soap and water. Male patients must get their beard cleaned and hair trimmed. Female patients should comb their hair properly. To lower IOP, anti glaucoma drugs may be used before surgery .

32. SURGICAL PROCEDURE INTRA CAPSULAR CATARACT EXTRACTION [ICCE] EXTRA CAPSULAR CATARACT EXTRACTION [ECCE] SMALL INCISION CATARACT SURGERY [SICS] PHACOEMULSIFICATION

33. INTRA-OCULAR LENS IPLANTATION Presently, intraocular lens (IOL) implantation is the method of choice for correcting aphakia. The IOL implant history had its beginning on November 29, 1949, when Harold Ridley, a British ophthalmologist, performed his first case. Types of intraocular lenses The commonly used material for their manufacture is poly-methyl- methacrylate (PMMA). Anterior chamber IOL These lenses situated entirely in front of the iris and are supported in the angle of anterior chamber. ACIOL can be inserted after ICCE or ECCE. These are not very popular due to comparatively higher incidence of bullous keratopathy .

34. 2. Iris-supported lenses . These lenses are fixed on the iris with the help of sutures, loops or claws. These lenses are also not very popular due to a high incidence of postoperative complications. 3. Posterior chamber lenses PCIOLs rest entirely behind the iris. They may be supported by the ciliary muscles or the capsular bag. Depending on the material of manufacturing, three types of PC-IOLs are available : Rigid IOLs are made entirely from PMMA. Foldable IOLs, to be implanted through a small incision (3.2 mm) after phacoemulsification are made of silicone, acrylic, hydrogel and collamer . Rollable IOLs are made of hydrogel .

35. Calculation of IOL power (Biometry ) The most common method of determining IOL power uses a regression formula called ‘SRK (Sanders, Retzlaff and Kraff ) formula’. The formula is P = A – 2.5L – 0.9K, where: P is the power of IOL, A is a constant, L is the axial length of the eyeball, K is corneal curvature .

36. REFERENCES September 2009.  Archived  from the original on 24 May 2015. Retrieved 24 May 2015 . Mohammadpour M, Shaabani A, Sahraian A, Momenaei B, Tayebi F, Bayat R, et al. (June 2019).  "Updates on managements of pediatric cataract" .  Journal of Current Ophthalmology .  31  (2): 118–126.  doi : 10.1016/j.joco.2018.11.005 .  PMC   6611931 .  PMID   31317088   "Recognizing Cataracts" . NIH News in Health. 2017-05-30. Retrieved 2020-02-02. Try wearing sunglasses or a hat with a brim. Researchers also believe that good nutrition can help reduce the risk of age-related cataract. They recommend eating plenty of green leafy vegetables, fruits, nuts and other healthy foods.