Search PubMed⌕ Search

Biomedical subjects

M A Mainster

Publications and source records attributed to M A Mainster.

70 records · Page 4Linked to original sources
PubMed1978

Solar retinitis, photic maculopathy and the pseudophakic eye.

The pseudophakic retina is shown to be at greater risk than the normal retina to photochemical damage from solar observation because current polymethylmethacrylate intraocular lenses allow greater ultraviolet retinal irradiances and higher retinal temperature increases than crystalline lenses. The implications of this finding are presented in terms of mechanisms for photic retinal damage, and relationships between photic maculopathy and degenerative retinal diseases are discussed.

Humans↗
PubMedDate not supplied

Contemporary optics and ocular pathology.

A significant advantage of Fourier optics over classical optics is that it permits a differentiation between optical and retinal-neural causes of visual impairment. The basic methods of Fourier optics are introduced in a nonmathematical manner, as are their relationship to current clinical methods of measuring visual performance. Potential ophthalmic applications for Fourier optics in both clinical diagnosis and pre-operative ocular evaluation are discussed, and the importance of clinical measurement of visual performance at intermediate contrast states is emphasized.

Cataract↗
PubMedDate not supplied

Small computers in the private ophthalmic practice. Practical considerations.

The use of small computers in private ophthalmic practice is introduced in a manner requiring no mathematical or data processing background. What a small computer is and does, and what costs and problems should be expected with contemporary equipment are presented. Business, educational and medical applications for small computers in ophthalmic practice are described, and the need for standardizing the language and recording formats of medical data processing is emphasized.

Accounting↗
PubMedDate not supplied

Purchasing a medical office minicomputer system. Guidelines and considerations.

Medical office computer systems can increase practice efficiency, but adequate minicomputer systems are still expensive, and some technical knowledge is needed if potential pitfalls in system acquisition and operation are to be avoided. A general introduction both to the capabilities and costs of currently available medical office computer systems is presented, and considerations which should be examined before acquiring an office computer are discussed.

Computers↗
PubMedDate not supplied

Transpupillary thermotherapy for age-related macular degeneration: long-pulse photocoagulation, apoptosis, and heat shock proteins.

OBJECTIVE: To provide a biophysical foundation for using transpupillary thermotherapy (TTT) to manage choroidal neovascularization in age-related macular degeneration (ARMD). METHODS: Retinal temperature rise in laser therapy is proportional to retinal irradiance (laser power/area) for a particular spot size, exposure duration, and wavelength. TTT is a low irradiance, large spot size, prolonged exposure (long-pulse), infrared laser photocoagulation protocol. Results from an experimentally confirmed, finite element model of retinal light absorption and heat conduction are used to analyze laser parameter selection and its consequences. Results from apoptosis, heat shock protein and hyperthermia research are used to examine how chorioretinal damage from clinical procedures might be reduced. RESULTS: Chorioretinal thermal equilibration occurs during long-pulse TTT photocoagulation. Retinal temperature increases are similar in the RPE where laser radiation absorption is significant and in the adjacent neural retina where there is negligible radiation absorption. For parameters used to treat occult choroidal neovascularization in lightly-pigmented fundi (800-mW, 810-nm, 3-mm retinal spot diameter, 60-sec exposure duration), the maximum chorioretinal temperature elevation is calculated to be roughly 10 degrees C, significantly lower than the 20 degrees C temperature elevations measured in threshold, conventional short-pulse retinal photocoagulation. CONCLUSIONS: To achieve a preselected temperature rise, TTT laser power must be increased or decreased in proportion to the diameter rather than the area of the laser spot. Clinical power settings should be adjusted for fundus pigmentation and media clarity because both of these factors affect absorbed retinal irradiance and thus retinal temperature rise. Noninvasive thermal dosimetry currently is unavailable for clinical retinal photocoagulation, but potential thermometric techniques include MRI, liposomal-encapsulated dyes, multispectral imaging or reflectometry, and subretinal or episcleral thermometry. TTT may be useful not only as independent therapy, but also as an adjunct to PDT, antiangiogenic drugs and ionizing radiation therapy in the management of neovascular ARMD. Low temperature, long-pulse photocoagulation is a potential strategy for decreasing neural retinal damage in subsequent TTT or short-pulse photocoagulation and perhaps even for treating glaucoma or retinal degenerations.

Animals↗