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Biomedical subjects

M L Hotchkiss

Publications and source records attributed to M L Hotchkiss.

7 recordsLinked to original sources
PubMed1985

Creating smaller eyedrops by reducing eyedropper tip dimensions.

The risk of toxicity and adverse systemic effects from eyedrops is increased because of the large size of conventional eyedrops. Although the tear film normally contains only 7 to 10 microliters, commercial eyedrops are 50 to 70 microliters. Much of the excess is pumped into the nasolacrimal system where it is systemically absorbed and capable of causing toxicity. A smaller eyedrop can achieve a maximal tear film concentration with far less systemic absorption. We found that changes in the outer and inner diameters of an eyedropper tip can alter eyedrop volume markedly. By selecting appropriate tip dimensions we produced eyedrops of less than 25 microliters; in some cases they were as small as 11 microliters.

Administration, Topical↗
PubMed1985

A comparison of Peritest automated perimetry and Goldmann perimetry.

Both Peritest perimetry and Goldmann visual field testing were performed on three groups of eyes. Eighty-one eyes had glaucoma with elevated intraocular pressures and abnormal visual fields determined by Goldmann perimetry. There were 47 eyes with suspected glaucoma, based on elevated IOPs and normal Goldmann visual fields. Nineteen eyes were normal. All visual fields were evaluated in masked fashion, and the results were compared. The Peritest had a high sensitivity in both glaucomatous (98.8%) and normal (94.7%) eyes. One half of the eyes with suspected glaucoma had abnormal Peritest results but normal Goldmann visual fields. These eyes were examined prospectively with color stereo discs and monochromatic nerve fiber layer photographs. One half of the eyes with suspected glaucoma and abnormal Peritest results also had photographic evidence suggesting optic nerve damage. Thus, early field defects detected by the Peritest perimeter in eyes with suspected glaucoma are likely to be representative of glaucomatous damage.

Adult↗
PubMed1985

Neodymium:YAG laser iridotomy in the cynomolgus monkey.

The histologic effects of various Neodymium:YAG laser energy levels were evaluated after iridotomy formation in cynomolgus monkey eyes. Scanning election microscopy of the corneal endothelium above the treated areas revealed no significant cell loss or pleomorphism when compared to the adjacent untreated areas. Light and phase contrast microscopy demonstrated closure of the iridotomies in most cases by a bridge of iris pigment epithelium. In several specimens, stromal tissue and pigment laden cells were present over the attenuated iris pigment epithelium. There were four lens opacities with rupture of the anterior lens capsule and anterior epithelial cell hyperplasia in one. No damage was apparent in the trabecular meshwork or retina with light microscopy or fluorescein angiography.

Animals↗
PubMed1984

Nonsteroidal anti-inflammatory agents after argon laser trabeculoplasty. A trial with flurbiprofen and indomethacin.

Seventy glaucomatous eyes received argon laser trabeculoplasty (ALT) to 180 degrees of the trabecular meshwork. Thirty-six eyes were treated with topical .03% sodium flurbiprofen, a nonsteroidal anti-inflammatory agent; 34 eyes received placebo. Eighteen eyes received ALT to 360 degrees of the meshwork; nine of these eyes were treated with topical 1% indomethacin and nine eyes received placebo. Eyes treated with flurbiprofen and indomethacin showed significantly less conjunctival injection following ALT. However, these agents did not significantly alter the anterior chamber reaction after laser therapy compared to placebo. Flurbiprofen-treated eyes showed a significantly smaller percent (32.6%) decrease in intraocular pressure (IOP) one day after ALT as compared to eyes receiving placebo (43.8%). In addition, a higher percentage of placebo treated eyes had a fall in IOP of at least 10 mmHg up to five weeks after ALT. Within the indomethacin protocol, the percentage change in IOP was comparable for both indomethacin and placebo treated eyes. Mild ocular symptoms (itching, burning, foreign-body sensation) developed in 77.8% of flurbiprofen-treated eyes, in 55.6% of indomethacin-treated eyes, and in 20.9% of eyes receiving placebo.

Adult↗
PubMed1984

Use of the neodymium:YAG laser to create iridotomies in monkeys and humans.

In a prospective study the Nd:YAG laser was used to create iridotomies in cynomolgus monkeys, using various levels of energy and pulse-trains of 1 to 9. Although no change occurred in the endothelial cell count of the cornea, opacities of the corneal endothelium and lens did occur. In addition, one eye showed rupture of the anterior lens capsule immediately behind the iridotomy. Most of the iridotomies in these animals closed within 3 to 4 weeks. Attenuated pigment epithelium bridged the gap within 9 days and in many sections it appeared that the iridotomies closed by fibrous contraction or early stromal regeneration. A prospective short-term clinical study evaluated argon and Q-Nd:YAG laser iridotomies in 42 eyes of 21 patients with primary chronic angle-closure glaucoma. In each patient one eye was randomly treated with an argon laser iridotomy and the fellow eye with a Nd:YAG laser iridotomy. In every case a patent iridotomy was created in one session. A mean of 12 +/- 11 and 0.033 +/- 0.025 Joules was required to complete an iridotomy with the argon and Nd:YAG lasers, respectively. Thirty percent of the argon iridotomies became sufficiently closed with pigment to require retreatment; whereas none of the Nd:YAG iridotomies closed. A postoperative rise in IOP greater than 10 mm Hg was seen in 38% argon- and 29% Nd:YAG-treated eyes. Although bleeding around the iridotomy occurred in 48% of eyes, in no case was this of significant consequence. No acute lens damage was observed in the Nd:YAG-treated human eyes, while 43% of lenses in the argon group had focal opacities. Thirty-three percent of Nd:YAG- and 24% of argon-treated eyes had focal, nonprogressive corneal opacities above the iridotomy. Specular microscopy showed a significant central corneal epithelial cell loss in argon laser eyes only. The potential of creating a laser iridotomy with a single burst of energy is extremely attractive and worthy of further investigation.

Animals↗
PubMed1981

Pathologic myopia and choroidal neovascularization.

In 14 of 27 eyes with choroidal neovascular membranes associated with severe myopia, visual acuity deteriorated two or more lines on the Snellen chart. Twelve of the 27 eyes became legally blind. Final visual acuity may be related to the position of the neovascular membrane within the posterior pole. Four of the eight eyes with new vessels outside of the foveal avascular zone had follow-up visual acuities of 6/12 (20/40) or better. Only one of five eyes with new vessels extending to the edge of the avascular zone had a final visual acuity of 6/12 (20/40) or better. Three of 14 eyes with a neovascular membrane beneath the foveal avascular zone had visual acuities of 6/12 (20/40) or better. Neovascularization associated with severe myopia clearly jeopardizes central visual acuity. Laser photocoagulation therapy may be useful in treating neovascular membranes outside the foveal avascular zone or extending to the edge of the perifoveal capillary network. A larger prospective study is needed to determine the guidelines for and efficacy of such treatment for patients with severe myopia who develop choroidal neovascularization.

Adult↗