Author's Response: Prosthetic Rehabilitation after Orbital Exenteration: A case series

Dear Editor,

We are thankful to the authors of letter to the editor entitled “improving the outcome of prosthetic rehabilitation following orbital exenteration” for having read our article and expressed their opinion.[1,2]

Authors have recommended the use of heat temperature vulcanized (HTV) silicones due to its superior mechanical, esthetic and handling properties. Reference quoted by authors (Belgam et al.) nowhere states HTV silicones to be esthetic. On the contrary, literature mentions HTV silicones to have low edge strength, opaque with lifeless appearance and not adequately elastic in function.[3] Therefore, for facial prosthesis, where esthetics is a major concern, room temperature vulcanization (RTV) silicones are preferred. HTV silicones are preferred for limb prosthesis etc., because of better mechanical properties. Mahajan and Gupta have also mentioned that HTV silicones are designed for engineering applications because of higher tear resistance and they require more intense mechanical milling of solid HTV stock elastomers when compared with soft RTV silicones.[4] Fabrication of prosthesis in HTV silicones is difficult as the material requires special milling machines which are expensive and not commonly available.[5]

Moreover, the references quoted for the above statement should be Bell et al.,[6] Lewis and Castleberry[7] and Lontz[8] instead of Begum et al.

Second point raised by the authors is the allergic reactions because of adhesives or industrial grade silicones. Allergic reaction due to adhesives is an issue and has been already mentioned by us in our article. We have used best quality medical grade silicones (Factor II Inc., USA) for fabrication of our prostheses, not industrial grade silicones. Adhesives prescribed were also of the best quality (Dow Corning/Technovent medical adhesive) and none of our patients have reported with any allergic reaction so far.

Corrosion of magnets has already been mentioned as a disadvantage in the manuscript. Attachments used in our patients may be harmful if they come into direct contact with the skin. However, the contact was only between two prostheses in our patients. Moreover, the pin and socket used were made of brass which is less prone to rust.

“Photodynamic iris” uses a liquid crystal display in the prosthesis to vary the pupil size as a function of the ambient light. But, there are no clinical trials so far using this concept.[9] Use of tinted glasses, negative sphere lenses can be used but these methods mandate the use of spectacles for the patients even if the natural eye has normal power and also add to the cost. We had used these particular methods specifically because these patients had financial constraints. Prosthesis with built-in blinking mechanism are not currently available in our country. We are sorry to bring it to the notice of the editor that again the references mentioned are wrong.

Osseointegrated implants undoubtedly provide better retention as compared to other mechanical methods. But, there are certain limitations already been discussed in our article.

We accept evisceration and enucleation, usually followed by placement of ocular implants, are treatment of choice in painful or disfiguring blind eye instead of exenteration.