Raphael's eyes and vision

The "C" in CHARGE - Coloboma (ocular)
The following are the details of what we know about Raphael's eyes and eyesight.

Medical Information
Raphael's notable eye conditions consist of the following:

1. Large right eye compared to his left eye (13/10/2006 - ophthalmologist).
2. Corneas (13/10/2006 - ophthalmologist) are measured as:
• 11.5 in the right eye (at the upper limit of the normal range);
• less than 9 in the left.
3. Intraocular pressures are:
• right 13/10/2006 (opthalmologist): 19mmHg
• left 13/10/2006 (opthalmologist): 14mmHg
• right 16/1/2007 (opthalmologist): 23mmHg (no evidence of glaucoma)
  
• right 17/4/2007 (opthalmologist): 21mmHg (no evidence of glaucoma)
• left 17/4/2007 (opthalmologist): 18mmHg
• right 18/4/2007 (opthalmologist - under GA): 15mmHg
  
4. Right eye is mildly hypermetropic (13/10/2006 - opthalmologist).
   
5. Left eye retinoscopy suggests some myopia (13/10/2006 - opthalmologist).
6. Dilated examination (13/10/2006 - opthalmologist) shows:
• Essentially normal right eye;
• Microphthalmic left eye with posterior staphyloma and excavated morning glory type disc. [the MRI report 18/12/2006 confirms this staphyloma]
7. The "left optic nerve appears smaller than the right, suggesting optic nerve hypoplasia" (MRI report 18/12/2006)
8. There is "also cupping of the optic disc / optic nerve head in the right globe also", "but much less severe than on the left" (MRI report 18/12/2006)
9. Right eye has an inferior chorioretinal coloboma at bottom of eye (5/6/2007 - opthalmologist, second opinion).

Explanation of the Medical Terms
The following is my simplified understanding of the terms and/or concepts listed above:

1. I suspect that Raphael's right eye is larger than his left becuase of the microphthalmic (genetic small eye) condition of his left eye (see point 6).
2. The cornea is the transparent covering over the pupil (black bit) and iris (coloured bit) of an eye. The coloured bit of Raphael's eye is larger than the coloured bit of his left eye.
   
3. intraocular pressure is a result of fluid in the eye. The normal range of this pressure is between 10mmHG and 20mmHg (mmHg is a measurement of pressure, see Torr). Raphael's right eye is at the upper limit of acceptable pressure. Under General anaesthetic another reading was taken that shows that there isn't a pressure problem. The readings that are taken under GA are much more reliable because normally the eye is squeezed to take the test which can give a higher reading than the actual pressure).
   
4. His right eye is mildly far sighted.
   
5. A retinoscopy is an objective method of examining some aspects of vision, it does not rely on a patient's response. a retinoscopy showed that the mechanics of his left eye have some myopia (short sightedness).
6. His left eye
• is small (microphthalmic) and underdeveloped;
• has a posterior staphyloma: bump on the back of the eye;
• has a morning glory disc: a large gouge where the optic disc is (in the internal part of the eye ball where the nerves converge). A morning glory disc is a specific type of optic disc coloboma. Colobomas are common CHARGE syndrome features. I don't have a photo of Raphael's morning glory disc but I have sketched what I think it might look like. With permission, I have also included a scan from the Australian CHARGE association handbook that describes the parts of an eye with a coloboma; and there are some great photos of them here if you want to see what they actually look like in other patients.
• . .
  
• . .
7. Raphael's left Optic nerve hypoplasia is the underdevelopment of the nerve that connects the left eye to the brain. I suspect that this is associated with the microphthalmia but I have no texts or professional advice to support this assertion.
8. The optic disc is the small portion of the back of the inside of the eye where the nerves converge and exit from the eye ball. The optic disc is a cup shape that is actually a blind spot in vision. "Optic disc cupping" refers to when this cup is enlarged thereby enlarging the blind spot and possibly indicating nerve damage. In Raphael's case the cupping noted on the MRI report is just a different way of different way of describing the morning glory disc.
9. There is also a coloboma (problem with the retina) down the bottom of his eye which is probably going to reduce his upper field of vision from his right eye.

The Implications of These Conditions

1. I don't think that there is any inherent problem with Raphael having his right eye larger than his left eye, except in this case the smaller eye is microphthalmic (see point 6).
2. I am not aware of any implications of the retinas being different sizes (right larger than left).
   
3. High intraocular pressure (fluid pressure in the eye) is called ocular hypertension. The risk associated with ocular hypertension is that it can lead to glaucoma which is the loss of retinal ganglion cells (nerve cells). This can in turn can lead to blindness. Because Raphael's right eye ( his only good eye) is at the higher end of normal pressure range, it is important to get his eyes checked regularly in case the pressure builds up.
4. Far sightedness in his right eye can be corrected with glasses but isn't necessary at this stage.
   
5. The short sightedness of his left eye could be compensated for with corrective lenses.
   
6. Left Eye:
• Some potential issues of his left eye microphthalmia can be mitigated with "Lens correction for refractive errors, often tinted; lighting according to needs, to control glare" (source: spedex)
• Raphael's left eye staphyloma is the obvious external sign of the morning glory disk inside his eye. The staphyloma itself is not large enough to cause any mechanical problems; it is the internal component (coloboma) which has the implications.
• Raphael's the morning glory type disc (coloboma) is so large that it prevents vision in the upper/central and sides for his left eye (including his macula and fovea). Some simple experimentation while putting an eye patch over his right eye demonstrates that he can only see toys as they enter the lower central field of vision. Further testing at 26 months reveal that his left eye vision appears to be suppressed when his right eye is not patched. When his right eye is patched he has enough left eye vision to allow him to walk and manipulate medium sized objects with ease. Colobomas cause an increased risk of retinal detachment. Detachment is disastrous for vision and can only be detected by expert examination or changes in eyesight for the person affected.
  
7. I don't know if Raphael's vision is effected by his left eye optic nerve hypoplasia. http://www.blindbabies.org/factsheet_onh.htm describes the characteristics of optic nerve hypoplasia (ONH) as ranging from "normal visual acuity to no light perception. The effect on the visual field may range from generalized loss of detailed vision in both central and peripheral fields (depressed visual fields) to subtle peripheral field loss."
8. The cupping of the left optic disc noted in Raphael's MRI is the same as the morning glory disc. See point 6 with regards to the implications of the morning glory disc.
9. Nothing can be done to repair his right eye coloboma, some people have described that these types of colobomas are like wearing a cap that obscures the top part of vision.

Summary:
"he has very limited or no useful vision in his left eye" (2/2/2007 - opthalmologist). At this stage is appears that Raphael has little practical vision in his left eye and his right eye also may have vision problems in the upper field and is mildly far sighted.

We have been told that nothing can be done to correct the vision problems with his left eye, but there is a good chance that he will have reasonable vision out of his right eye with corrective lenses if necessary.

I have not given up all hope for his left eye yet because I know that he has at least some vision in that eye.

Practical Tests by Behaviour at about 1 year old
Annie and I have performed some practical tests on his eyesight by eye patching each eye in turn and trying to see what he can see by introducing interesting objects into his field of vision.

His right eye seems to have an excellent field of vision and it appears that he can spot toys in the centre, high, low, left and right. He also responds (smiles) to a person who smiles when they are five metres away.

His left eye is hopeless compared to his right. When his right eye is covered he pulls back as though he has been blinded and pulls at the eye patch to try to remove it. This is a very different reaction to when his other eye was covered. His left eye field of vision seems to be very poor. He can only sight toys as they enter the lower central field of vision. He does not respond to anything presented in the centre, top, left, or right of his vision.

When not eye patched and looking up his right eye tracks an object well, but his left eye rolls back and is clearly not even centred on the target at all.