Abstract
Proper use of ophthalmoscopic contact lenses for retinal photocoagulation requires knowledge of their comparative magnification, spot size, and field of view. We determined these parameters for four commonly used lenses, using data measured from optical components of the lenses and a commonly used photo-coagulator slit-lamp and spot size changer. A Krieger lens has 8% more working field of view and 29% less magnification than a Goldmann lens. A Panfundoscope lens has 84% more working field of view and 24% less magnification than a Goldmann lens. A Mainster lens has 58% more working field of view and 3% more magnification than a Goldmann lens. For Goldmann, Krieger, Panfundoscope, and Mainster lenses, respectively, retinal spot size is 8%, 53%, 41%, and 5% greater than photo-coagulator spot size settings. The field of view of each lens is increased in myopic and decreased in hyperopic patients. Anterior segment irradiance is higher than retinal irradiance for 1000 microns spot size settings with a Panfundoscope or Mainster lens, and this setting should be avoided, especially in patients with hazy ocular media.
Full text
PDF
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Birngruber R., Lorenz B., Weinberg W., Greite J. H., Gabel V. P. Komplikationen bei der Laserkoagulation durch das Panfunduskop. Fortschr Ophthalmol. 1983;79(5):434–437. [PubMed] [Google Scholar]
- Blankenship G. W. Panretinal laser photocoagulation with wide-angle fundus contact lens. Ann Ophthalmol. 1982 Apr;14(4):362–363. [PubMed] [Google Scholar]
- Lobes L. A., Jr, Benson W., Grand M. G. Panfunduscope contact lens for argon laser therapy. Ann Ophthalmol. 1981 Jun;13(6):713–714. [PubMed] [Google Scholar]
- Mainster M. A., White T. J., Tips J. H., Wilson P. W. Retinal-temperature increases produced by intense light sources. J Opt Soc Am. 1970 Feb;60(2):264–270. doi: 10.1364/josa.60.000264. [DOI] [PubMed] [Google Scholar]
- Pomerantzeff O., Pankratov M., Wang G. J., Dufault P. Wide-angle optical model of the eye. Am J Optom Physiol Opt. 1984 Mar;61(3):166–176. doi: 10.1097/00006324-198403000-00004. [DOI] [PubMed] [Google Scholar]
- Rol P., Fankhauser F., Kwasniewska S. New contact lens for observation and coagulation of the retina and choroid. Am J Ophthalmol. 1988 May 15;105(5):479–482. doi: 10.1016/0002-9394(88)90238-3. [DOI] [PubMed] [Google Scholar]
- Schlegel H. J. Eine einfache Weitwinkeloptik zur spaltlampenmikroskopischen Untersuchung des Augenhintergrundes (Panfundoskop) Doc Ophthalmol. 1969;26:300–308. doi: 10.1007/BF00943989. [DOI] [PubMed] [Google Scholar]
- Yannuzzi L. A., Slakter J. S. Macula photocoagulation lens. Am J Ophthalmol. 1986 May 15;101(5):619–620. doi: 10.1016/0002-9394(86)90963-3. [DOI] [PubMed] [Google Scholar]