management of achromatopsia. prescribe or not: a case report presented by k.m. law, school of...

Management of achromatopsia. Prescribe or not: A case report

Presented by K.M. Law,

School of Optometry,The Hong Kong Polytechnic University,

Hong Kong, China

Background

• Achromatopsia is a congenital, inherited visual disorder in which cone function is either absent or reduced.

Clinical characteristics of achromatopsia

1. Reduce VA

2. Photophobia

3. Significant refractive error

4. Reduce or complete loss of colour discrimination

Case history

• A 34-year-old accountant diagnosed of achromatopsia since childhood.

• Subjective refraction

OD: -13.00 DS (VA: 10/100-)

OS: -14.50 / -1.50 X 180 (VA: 10/100-)• Abnormal colour vision• Reduced contrast sensitivity• Corning 527X filter was used to reduce light sen

sitivity currently

Fundus

OD OS

Contact lens fitting

OD (Flexcon Red Prosthetic) Fig. 3

OS (Opulens 42C)Fig. 4

BC / Dia /Power

8.80 / 14.5 /-11.50

8.90 / 14.5 /-12.00 / -1.75 x 180

Coverage / Centration

Full / Centre Full / Centre

Rotation N/A No rotation

Fitting Acceptable Acceptable

VA 10 / 80+ 10 / 80

Remarks: No significant improvement in colour vision , contrast sensitivity and VA but with increased visual comfort with red lens.

Contact lenses

OD with prosthetic red lens OS with clear lens

Discussions

• Photophobia is a common complain of people suffered from achromatopsia.

• Symptoms of photophobia in patients with achromatopsia may be relieved due to attenuate light reaching the retina with the use of tinted contact lens.

• Tinted contact lens may provide better visual comfort than tinted spectacle as it could limit periphery glare, eliminate back surface reflections and align visual axis better than spectacles.1

Conclusions

1. Tinted contact lenses should be considered if patient found significant improvement in visual comfort even though the improvement of visual acuity was minimal clinically.

2. Tinted zone of contact lenses should cover and well beyond the pupil margin under dim and bright conditions.

3. Extra care should be needed to minimize contact lens complications.

Reference

• Red contact lenses for alleviation of photophobia in patients with cone disorders. Park WL. Sunness JS. American Journal of Ophthalmology. 137(4):774-5, 2004 Apr.